Difference between revisions of "Team:SSTi-SZGD/Applied Design"

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<link rel="stylesheet" type="text/css" href="https://2018.igem.org/Team:SSTi-SZGD/css/Applied_Design?action=raw&ctype=text/css"/>
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<script src="https://2018.igem.org/Team:SSTi-SZGD/js/Applied_Design?action=raw&ctype=text/javascript" type="text/javascript" charset="utf-8"></script>
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<body>
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<!--Content-->
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<div class="container Content">
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<!--paragraph one-->
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<section class="col-xs-12 col-sm-10">
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<p class="title"><span>What's the problem & Our vision?<!--{cn}存在着什么问题和我们的解决方案？--></span></p>
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<div class="content">
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<p>
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After more than twenty years of rapid development, China's cosmetics market, known as "beauty economy", has become the world's second largest cosmetics market after the United States<!--{cn}经过20多年的迅猛发展，被称为“美丽经济”的中国美容化妆品市场已经成为仅次于美国的全球第二大化妆品消费国-->
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<sup>[1]</sup>
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. According to the "analysis of market size and development trend of China's cosmetics industry in 2017"<!--{cn}。据《2017年中国化妆品行业市场规模及发展趋势分析》-->
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<sup>[2]</sup>
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, CAGR (Annual compound growth rate) of China's cosmetics industry was 9.1% in the past five years, far higher than the global aver age CAGR of 4.1%. It is estimated that the market size of China's cosmetics industry could reach 490.6 billion in 2019.<!--{cn}统计，过去五年我国化妆品行业CAGR（年复合增长率）为9.1%，远高于全球平均CAGR的4.1%，预计2019年，我国化妆品行业市场规模可达4906亿元。-->
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<span>(see Fig.1)</span>
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From the current situation of the cosmetics industry, China's cosmetics market has a broad prospect.<!--{cn}从化妆品行业现状来看，中国化妆品市场有着广阔的前景。-->
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</p>
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<div class="img col-xs-12 col-sm-7">
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<img src="https://static.igem.org/mediawiki/2018/8/8b/T--SSTi-SZGD--applied_design_one.png"/>
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<p>
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Fig.1. Analysis chart of development trend of Chinese cosmetic market.<!--{cn}图1. 中国化妆品市场发展趋势分析图。-->
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</p>
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<div class="clearfix"></div>
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</div>
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<p>
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At present, as the living standard improves, demand for anti-aging products is growing, and the use of natural polymer ingredients in cosmetics to promote skin repair and wrinkle removal increases every year. Among the commonly used polymer ingredients, hyaluronic acid (HA), a type of macromolecular mucopolysaccharide, is extensively used in cosmetics due to its excellent permeability, moisturizing, and biocompatibility properties, so as to improve skin humidity and achieve the effects of skin rejuvenation.
 +
<!--{cn}目前，由于人们生活水平提高，消费者对延缓衰老的需求越来越多，化妆品中促进皮肤修复和除皱效果的天然聚合物成分的使用每年都在增加。在主要使用的高分子材料中，透明质酸是一种高分子黏多糖，因其具有优异的渗透性、生物相容性和良好的水溶性，广泛的应用于化妆品中，以提高皮肤的湿度达到皮肤修复和除皱的效果。-->
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</p>
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<p>
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The biological activity and water retention effects of hyaluronic acid is directly related to its relative molecular weight (Mr). High and middle molecular weight HA (Mr≥1-2×106 Da) with great viscoelasticity, lubrication, and moisturizing effects are widely used in cosmetics, while low molecular weight HA (Mr≤1×104 Da) has potential anti-tumor effects, and promotes wound healing and immune regulation
 +
<!--{cn}透明质酸的生物活性和使用效果与其相对分子量（Mr）直接相关：高中分子的透明质酸（Mr≥（1-2）×106）具有较好的粘弹性、保湿性以及抑制炎性反应等功能被广泛的用于化妆品中；Mr≤1×104的低分子量透明质酸具有抗肿瘤、促进创伤愈合以及免疫调节等作用-->
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<sup>[3]</sup>
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.<!--{cn}。-->
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</p>
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<p>
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HA has prominent effects on promoting tissue remodeling and reducing scar formation, thereby it is a star material in cosmetic products. Most products on the market containing HA and its derivative sodium hyaluronate are facial masks and cream formulations. Although these products make skin appear softer and smoother, due to the barrier effect of skin epidermis, it is difficult for active ingredients to efficiently penetrate through the stratum corneum and release into the deeper skin for a long-term effect, unless using surgical methods (i.e. injection). Surgical methods, on the other hand, usually result in facial bruising, skin necrosis and intense pain, which could seriously affect facial nerve system and result in rigid facial expressions. Injection may also trigger immune reactions, resulting to temporary swelling, headaches, mild nausea and minor numbness
 +
<!--{cn}透明质酸对促进组织重塑和减少疤痕形成有显著的影响，因此它在化妆品中是一个热门的材料。市面上含透明质酸及其衍生物透明质酸钠的化妆品主要为贴剂和乳膏剂。虽然这些产品使皮肤看起来更柔软、更光滑，但由于皮肤表皮的屏障作用，有效成分很难有效穿透角质层并释放到深层皮肤中以达到长期效果。除非使用手术方法或注射。另一方面，手术方法通常会导致面部损伤、皮肤坏死和剧烈疼痛，严重的可能影响面部神经系统导致面部表情僵硬。注射也可能引起免疫反应，导致暂时的肿胀、头痛、轻微的恶心和轻微的麻木-->
 +
<sup>[4]</sup>
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. Therefore, searching for an alternative method for effectively and safely delivering HA into skin dermis has become necessary.
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<!--{cn}。因此寻找一种有效且安全的方法使透明质酸进入皮肤是必要的。-->
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</p>
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<p>
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In addition, compare to high molecular weight HA, low molecular weight HA can be more efficiently absorbed across skin epidermis. However, its moisturizing and viscoelastic properties are far inferior to high molecular weight HA
 +
<!--{cn}另外，与高分子量的透明质酸相比，低分子量的透明质酸能更有效的被皮肤吸收，然而它的保湿性以及粘弹性远不及高分子量的透明质酸-->
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<sup>[5]</sup>
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.<!--{cn}。-->
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</p>
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<p>
 +
Thereby, we endeavor to develop a new cosmetic application method that combines the advantages of high and low molecular weight HA, as well as eliminating the tedious and potentially dangerous operation of injection and surgery, to achieve lasting effects of skin rejuvenation and wrinkle removal.
 +
<!--{cn}所以我们努力开发一种新型的美容应用方法，结合高分子量与低分子量的透明质酸的优点，消除繁琐且危险的注射以及手术操作，以达到修复肌肤和除皱的长期效果。-->
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</p>
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</div>
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</section>
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<!--paragraph two-->
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<section class="col-xs-12 col-sm-10">
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<p class="title"><span>Comparison of products in the market<!--{cn}与市面上的产品对比--></span></p>
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<div class="content">
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<p>
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Based on the understanding of the current cosmetic market, and refer to relevant resources, we came across a new method that has the potential to replace the traditional injection approach -- "microneedle delivery system", which represents a new stage of technology development in cosmetics industry. The main advantage of microneedle system is that it can pierce through the skin in a non-invasive and painless way, and help with the efficient delivery of macromolecular ingredients. It is safer than surgery or injections, while being more effective than ordinary moisturizing cream or masks.
 +
<!--{cn}通过了解目前的化妆品市场以及参考相关资源，我们发现了一种取代传统注射方式的新方法-“微针传输系统”，代表着化妆品行业中技术发展的新阶段。微针的主要优点是以一种非侵入性和无痛的方式进入皮肤，并能有效地输送大分子成分。这种方式比手术以及注射更加安全，同时也比普通的贴剂和乳膏剂更加有效。-->
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</p>
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<p>
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The current available microneedle delivery products are made of silicon wafer, metal materials or natural sugars
 +
<!--{cn}目前流行的微针产品通常采用硅晶片、金属材料或者天然糖类制备而成-->
 +
<sup>[6]</sup>
 +
. Silicon wafer based microneedles, fabricated using MEMS (micro-electromechanical system) microfabrication technology, are  sharper than those made of polymer, sugar or metal<!--{cn}。最初的硅微针的是利用MEMS（微电子机械系统）微制造技术以及深反应离子蚀刻术制成。硅晶片微针的最大优点在于，其尖端比聚合物、糖类和金属微针更尖锐-->
 +
<sup>[7]</sup>
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. It is conducive to penetrate through the skin epidermis and reducing discomfort. However, because silicon absorbs proteins, when use in deeper skin, white blood cells are drawn to the material to induce stress response on the affected area
 +
<!--{cn}，有利于刺入皮肤表皮。虽然尖而细的硅微针能减少人体不适感，但硅材料表面会吸附蛋白质，促使白血球和微针粘合，被刺入区域可能会产生应激性反应-->
 +
<sup>[7]</sup>
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. Microneedles made of silicon wafer
 +
<!--{cn}。同时硅微针-->
 +
<span>(see Fig.2)</span>
 +
also have drawbacks such as complex preparation procedures, high processing cost and requirements, and fragile proposition. The nature of the material can lead to easy breakage of the tips under the skin, combining with a low biocompatibility property, tip residues can result to skin infection
 +
<!--{cn}还有其他缺点，比如制备过程复杂、加工成本高，以及制备环境的洁净度要求等。此外，硅材料的生物相容性低，在皮肤上作用时有断裂的情况发生时，皮下的残余物可能会引发排斥反应和感染-->
 +
<sup>[8]</sup>
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.<!--{cn}。-->
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</p>
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<p>
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Metal based microneedles
 +
<!--{cn}金属微针-->
 +
<span>(see Fig.2)</span>
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, generally made of stainless steel, titanium, nickel, etc., are fabricated by laser cutting, laser etching and wet etching
 +
<!--{cn}的制备方法相对简单，多以不锈钢、钛、镍等金属或合金为原材料，采用激光切割、激光蚀刻法以及湿刻法制备-->
 +
<sup>[8]</sup>
 +
. Metal material, usually used in combination with serum, can cause painful sensation when use, and frequent use may cause pore enlargement. Also, because metal-based microneedles are usually re-used, it may lead to the contamination of blood-transferrable diseases, i.e. AIDS, hepatitis and so on
 +
<!--{cn}。而金属微针的最大劣势在于制备微针时的效率较低，不利于大规模生产。金属材质会造成明显的疼感，频繁使用会造成毛孔增大，如果共用可能会残留他人血液，易导致艾滋病、肝炎等得传播-->
 +
<sup>[8]</sup>
 +
. With regards to industrial production, metal based microneedle, with its relatively complex preparation requirement, is not prone to mass production. Sugar based microneedles are usually prepared from maltose, trehalose, sucrose, fructose, etc. These sugar materials require stringent preparation and storage conditions. If not stored properly, they can absorb moisture easily and result to reduced hardness
 +
<!--{cn}。糖类微针通常由麦芽糖、海藻糖、蔗糖、果糖等制备而成，但糖类的缺陷在于制备以及储存，使用过程中易吸潮，导致硬度降低或者药物变质等-->
 +
<sup>[9]</sup>
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<!--.{cn}。-->
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</p>
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<p>
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In recent years, the preparation of microneedles with natural and degradable polymer biomaterials has become a hot topic.
 +
<!--{cn}因此，近年来以天然可降解的高分子聚合物材料为主要原料制备的微针头成为研究热点。-->
 +
<span>(see Fig.2)</span>
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There have been a variety of raw materials, i.e. polyvinyl alcohol, polylactic acid, chitosan, carboxymethylcellulose, HA, silk protein, etc. being used in microneedle fabrication
 +
<!--{cn}用于制备微针的高分子材料比如聚乙烯醇、聚乳酸、壳聚糖、羧甲基纤维素、透明质酸、蚕丝蛋白等-->
 +
<sup>[9]</sup>
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. Among them, HA, with its excellent moisturizing property, biocompatibility, and relatively simple preparation method, has become a popular microneedle biomaterial.
 +
<!--{cn}。因透明质酸具有优异的保湿性能、良好的生物相容性和制备方法简单等，已成为一种流行的微针生物相容性材料。-->
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</p>
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<div class="img col-xs-12">
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<img src="https://static.igem.org/mediawiki/2018/8/8e/T--SSTi-SZGD--applied_design_two.png"/>
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<p>
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Fig.2.(A) silicon wafer microneedle, (B) metal microneedle, (C) macromolecule microneedle.
 +
<!--{cn}图2. （A）硅晶片微针，（B）金属微针，（C）高分子微针。-->
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</p>
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<div class="clearfix"></div>
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</div>
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<p>
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There are existing HA micro-needle eye patch products on the market, for example, Quanis(R) from Japan and Acropass(R) from South Korea.
 +
<!--{cn}市面上也有正在售卖的透明质酸微针眼贴，例如日本的Quanis和韩国的Acropass，-->
 +
<span>(see Fig.3)</span>
 +
The manufacturing process for these products is air blast stretching technology. In this way, microneedles are of uniform shape, but with weak mechanical strength and short in needle size, which hamper the efficient penetration into the skin. In addition, these products are used in combination with the water retention serum to assist the better absorption of the serum. In this regard, microneedle is only used for its auxiliary function, which greatly undermines its value and potential.
 +
<!--{cn}他们制备微针的工艺是鼓风拉伸方式，这样制备出来的微针形态一致，但是机械强度较弱且尺寸较短，这阻碍了皮肤的有效渗透。除此之外，他们的使用方式需要结合精华液使用，以辅助精华液进行更好的吸收。在这方面，微针仅用于辅助功能，这大大降低了它的价值和潜力。-->
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</p>
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<div class="img col-xs-12">
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<div class="col-xs-12 col-sm-6 active">
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<img src="https://static.igem.org/mediawiki/2018/1/13/T--SSTi-SZGD--applied_design_two2.jpeg"/>
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</div>
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<div class="col-xs-12 col-sm-6 active">
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<img src="https://static.igem.org/mediawiki/2018/5/54/T--SSTi-SZGD--applied_design_two3.jpeg"/>
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</div>
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<p class="active">
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Figure.3. Various types of microneedles in current market
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<!--{cn}图3. 目前市场上各种类型的微针-->
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</p>
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</div>
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 +
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</div>
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</section>
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<!--paragraph three-->
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<section class="col-xs-12 col-sm-10">
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<p class="title"><span>How to change the situation?<!--{cn}如何改变现在的情况？--></span></p>
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<div class="content">
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<p>
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We would like to formulate a new type of HA based microneedle with both the penetration function and moisturizing ability, that is, these microneedles are made of HA material with sufficient strength to pierce through skin epidermis, then release HA molecules to exert the water retention effect.
 +
<!--{cn}我们想要建立一种新型的具有渗透和保湿能力的透明质酸微针，这些透明质酸微针具有足够的强度渗透皮肤表皮，然后释放透明质酸分子来发挥保湿作用。-->
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</p>
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<p>
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HA is one of the most functional macromolecules in nature. As an important part of the natural extracellular matrix, HA plays an important role in various biological processes. However, because of its easy degradation and poor mechanical properties, natural HA is not suitable for microneedle preparation. Compared with natural HA, chemical cross-linking of HA can efficiently enhance its stability, mechanical strength, in-situ swelling ability of the microneedle within skin, and decrease its biodegradability. Also, as cross-linking procedures result to a hydrogel like material with stable 3D structures
 +
<!--{cn}透明质酸是自然界中功能最多的大分子之一。作为天然细胞外基质的重要组成部分，透明质酸在各种生物过程中发挥重要作用。由于它的易于降解和较差的机械性能，天然的透明质酸不适合制备微针。与天然透明质酸相比，化学交联的透明质酸能有效地提高其稳定性、机械强度、原位膨胀能力并降低其生物降解性。此外，由于透明质酸经交联剂交联修饰得到的具有三维立体结构的高分子凝胶-->
 +
<span>(see Fig.4)</span>
 +
, it is better suitable for crafting microneedles.
 +
<!--{cn}，它更适合制作微针。-->
 +
</p>
 +
<div class="img col-xs-12 col-sm-7">
 +
<img src="https://static.igem.org/mediawiki/2018/d/d1/T--SSTi-SZGD--applied_design_three.jpeg"/>
 +
<p>
 +
Fig.4. Hyaluronic acid cross-linking
 +
<!--{cn}图4. 透明质酸交联-->
 +
</p>
 +
<div class="clearfix"></div>
 +
</div>
 +
<p>
 +
At present, the mainstream chemical cross-linking agents for HA are diethylsulfone (DVS) and 1, 4-butanediol diglycidyl ether (BDDE). DVS, although widely used in R&D, has high cytotoxicity. Not only this toxic substance is likely to be accumulated in the body after implantation, but also it may affect normal tissue growth due to calcification of the implant. In comparison, BDDE is considered to be the mostly commonly used cross-linking agent in preparation of cosmetic HA fillers. BDDE is biodegradable, much less toxic and more reactive than DVS, thereby safer for biomedical applications.
 +
<!--{cn}目前，透明质酸的主流化学交联剂为二乙烯基砜(DVS)和1，4-丁二醇二缩水甘油醚(BDDE)。DVS虽然在研发中被广泛使用，但它具有很强的细胞毒性。不仅这种有毒物质会在体内积累，而且植入后易产生钙化现象，在一定程度上影响正常组织生长。相比之下，BDDE在用于制备化妆品的透明质酸填充材料中被认为是最常用的交联剂。BDDE是可生物降解的并且相对DVS毒性小和反应性更强，因此对生物医学应用方面更安全。为了实现具有一定形态的微针，开发了一种将高分子透明质酸和透明质酸水凝胶固化成微针头贴片的模板，以便更好的应用在皮肤表面。-->
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</p>
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</div>
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</section>
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 +
<!--paragraph four-->
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<section class="col-xs-12 col-sm-10">
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<p class="title"><span>How to achieve it?<!--{cn}如何实现它？--></span></p>
 +
<div class="content">
 +
<p>
 +
<ol>
 +
<li>
 +
We engineered Bacillus subtilis bacteria to produce HA (HMW and LMW separately) by transgenic methods. Once the secreted raw HA are separated and purified by ethanol precipitation, HA molecules are freeze-dried to form powder as a starter material for the following cross-linking procedures.
 +
<!--{cn}我们通过转基因的方法构建了枯草芽孢杆菌生产高分子和低分子的透明质酸，生产后的透明质酸被乙醇沉淀分离纯化后，透明质酸就会被冻干形成粉末，作为后续的透明质酸交联的材料。-->
 +
</li>
 +
<li>
 +
We cross-linked LMW HA with less toxic and better reactive crosslinking agent, BDDE, to obtain a hydrogel form of HA. This hydrogel containing HA nanoparticles possesses stable structure, improved mechanical strength and would be less sensitive to enzymatic degradation.
 +
<!--{cn}我们将毒性较小且反应性好的BDDE交联剂与低分子透明质酸进行交联，以获得透明质酸水凝胶，这种透明质酸水凝胶具有稳定的结构，提高了机械强度并且不易被酶降解。-->
 +
</li>
 +
<li>
 +
Cross-linked HA and HMW HA molecules are blended in certain ratio to obtain a mixture, which is then poured into the a specially designed mould for microneedle fabrication. Our mould for microneedle fabrication is a 3D printed photosensitive resin, which is a high-strength and high-temperature proof material with features of energy saving, low pollution, fast curing speed and high production efficiency.
 +
<!--{cn}交联的透明质酸和高分子透明质酸以一定的比例混合，然后倒入专门设计的模具中。我们的模板是一种3D打印的光敏树脂，这是一种高强度、耐高温的防水材料，具有节约能源、污染小固化速度快、生产效率高等特点。-->
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</li>
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</ol>
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</p>
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</div>
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</section>
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 +
<!--paragraph five-->
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<section class="col-xs-12 col-sm-10">
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<p class="title"><span>Production formulation<!--{cn}生产规划--></span></p>
 +
<div class="content">
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<p class="subtitle">HA crosslinking process<!--{cn}透明质酸交联工艺--></p>
 +
<p>
 +
Cross-linked HA (cHA) reagent solution was prepared by mixing 200μl of 1, 4-butanediol diglycidyl ether (BDDE) into 9.8ml of 0.25M NaOH (pH13). Approximately 1.0g of HA powder was added to the cHA reagent solution and mixed thoroughly at 40 ℃ for 2h. The prepared hydrogel was ground, squeezed out and screened with 170 mesh sieve to get smaller particles.
 +
<!--{cn}将200μL的1,4-丁二醇二缩水甘油醚（BDDE）混入9.8mL的0.25M NaOH（pH13）中制备交联透明质酸（cHA）试剂溶液。向cHA试剂溶液中加入约1克的透明质酸粉末，并在40°C下彻底混合2 h。将制备的水凝胶研磨，挤出并用170目筛筛分以获得更小的颗粒。-->
 +
</p>
 +
<p class="subtitle">Preparation of HA microneedle<!--{cn}制备透明质酸微针--></p>
 +
<p>
 +
HA molecules and crosslinked HA hydrogel are mixed and dissolved in ultra-pure water in different proportions, and the viscous polymer solution is mixed uniformly with magnetic agitator at room temperature. Apply the viscous solution to the mold under vacuum pressure and use the blade to peel off the remaining solution. After curing at room temperature overnight, the transparent microneedle patch is successfully prepared.
 +
<!--{cn}将不同比例的透明质酸和交联后的透明质酸水凝胶在超纯水中混合溶解。在室温下，粘性聚合物溶液在磁力搅拌器中混合均匀。并在真空压力下将粘稠溶液施加到模具上，并通过使用刀片将留在模具边缘上的残余溶液剥离。在室温下过夜固化后，成功制备固化的透明质酸微针贴片。-->
 +
<span>(see Fig.5)</span>
 +
</p>
 +
<div class="img col-xs-12">
 +
<img src="https://static.igem.org/mediawiki/2018/4/4e/T--SSTi-SZGD--applied_design_five.png"/>
 +
<p>
 +
Fig.5. Flow chart of preparation of microneedle
 +
<!--{cn}图5. 微针制备流程图-->
 +
</p>
 +
<div class="clearfix"></div>
 +
</div>
 +
<p class="subtitle">Characterization of microneedle<!--{cn}透明质酸微针的特性--></p>
 +
<p>
 +
In order to make HA more effectively absorbed by the skin, we crafted a mould with cone shaped needles. This particular shape is believed to provide the needles with sufficient mechanical strength and stability, which enables HA entering into the deeper skin efficiently.
 +
<!--{cn}为了使透明质酸更有效的被皮肤吸收，模具的微针结构是锥形的。这种特殊的形状被认为能提供微针具有足够的机械强度和稳定性，使透明质酸能够有效地进入深层皮肤。-->
 +
<span>(see HA-MN results)<!--{cn}（看透明质酸微针的结果）--></span>
 +
Given sufficient reaction time, eventually the entire patch would be absorbed completely by the skin with no waste produced. In case of shorter reaction time, the remaining patch can be disposed as ordinary kitchen garbage to undergo natural degradation.
 +
<!--{cn}由于透明质酸是可生物降解的，使用后的贴片可作为普通厨房垃圾处理，并经历自然降解。-->
 +
</p>
 +
<p>
 +
In the future, we plan to craft the HA microneedle patches into several shapes to accommodate different needs.
 +
<!--{cn}在未来，为了便于面部使用，我们将会把透明质酸微针头贴片设计成几种形状。-->
 +
</p>
 +
<div class="table-responsive">
 +
<table class="table table-bordered">
 +
<tr>
 +
<th>Shape<!--{cn}形状--></th>
 +
<th>Purpose<!--{cn}用途--></th>
 +
</tr>
 +
<tr>
 +
<td>Triangle<!--{cn}三角形<--></td>
 +
<td>Used for frown lines, crow's-feet<!--{cn}用于眉间纹和鱼尾纹--></td>
 +
</tr>
 +
<tr>
 +
<td>Crescent<!--{cn}月牙状--></td>
 +
<td>Used for nasolabial folds or surrounding eye area<!--{cn}用于法令纹和眼周--></td>
 +
</tr>
 +
<tr>
 +
<td>Rectangle<!--{cn}矩形--></td>
 +
<td>Used for forehead wrinkles<!--{cn}用于抬头纹--></td>
 +
</tr>
 +
</table>
 +
</div>
 +
<div class="img col-xs-12">
 +
<img src="https://static.igem.org/mediawiki/2018/d/d0/T--SSTi-SZGD--applied_design_five2.jpeg"/>
 +
<div class="clearfix"></div>
 +
</div>
 +
</div>
 +
</section>
 +
 +
<!--paragraph six-->
 +
<section class="col-xs-12 col-sm-10">
 +
<p class="title"><span>Product Design Considerations<!--{cn}产品设计考虑因素--></span></p>
 +
<div class="content">
 +
<p>
 +
We have three aspects to consider in the product design process: product safety, product material and product effectiveness.
 +
<!--{cn}我们有三个地方需要考虑，产品的安全，产品的成型以及产品的有效性。-->
 +
</p>
 +
<p>
 +
Firstly, product safety aspect is related to the source of HA. Most of HA material and its derivatives used in the market are of <!--{cn}第一，产品的安全也就是关于透明质酸的来源，市面上应用的透明质酸大多使用-->
 +
<i>Streptococcus origin<!--{cn}马疫链球菌--></i>
 +
. <!--{cn}生产透明质酸，这是种条件致病菌对生产相关人员和环境存在一定潜在风险。-->
 +
<i>Streptococcus<!--{cn}兽疫链球菌--></i>
 +
strain is a conditional pathogenic bacterium that poses potential human and environmental risks. Because of it endogenous endotoxin, its by-products, i.e. HA, are likely to carry the toxin. In the current project, we use food-grade <!--{cn}本身具有内毒素，发酵生产出来的透明质酸有携带毒素的可能性。在目前的项目中，我们使用了食品级的-->
 +
<i>B.subtilis<!--{cn}枯草芽孢杆菌--></i>
 +
  to produce HA. This bacterium strain is well studied with genome fully sequenced, has no endotoxin, and requires low nutrition to reduce production cost. Therefore the raw material for our product is of less biosafety concern. <!--{cn}来生产透明质酸。这种细菌菌株在基因组测序中得到了很好的研究，所需营养要求低降低了生产成本且无内毒素。因此，我们产品的原材料减少了生物安全的考虑。-->
 +
</p>
 +
<p>
 +
Secondly, product material refers to the cross-linking process of HA. Our HA microneedle using cross-linked low molecular weight (~17 kDa) HA to obtain a hydrogel. Because the high molecular weight (~1500 kDa) HA has longer polymer chain structure, which when cross-linked, results to more coiled structure formation and greater self-association. This somewhat “packed” structure is unstable and unable to form a homogeneous hydrogel. In contrast, low molecular weight HA, because of its shorter polymer chain structure, has a greater chance of forming inter-molecular bonds, so that hydrogel with stable 3-D structure is more likely to be formed[10].<!--{cn}第二，产品的成型指的是透明质酸的交联工艺，我们的透明质酸微针使用的是低分子量的透明质酸进行交联形成水凝胶。因为高分子量的透明质酸聚合物链长、螺旋结构和自缔合性更强，这可能会为高分子量透明质酸交联时提供了一种填充结构，交联过后不稳定并且成型效果差。然而，由于其较短的聚合物链结构，更有可能形成分子间的化学键，因此交联后更可能形成具有稳定的三维结构的水凝胶。-->
 +
<span>(see Fig.6)</span>
 +
</p>
 +
<div class="img col-xs-12">
 +
<img src="https://static.igem.org/mediawiki/2018/0/02/T--SSTi-SZGD--applied_design_six.png"/>
 +
<p>
 +
Fig.6. The cross-linking state of hyaluronic acid
 +
<!--{cn}图6. 透明质酸的交联状态-->
 +
</p>
 +
<div class="clearfix"></div>
 +
</div>
 +
<p>
 +
Thirdly, the product effectiveness is decided by microneedle fabrication technology. In order for the microneedle to enter the skin epidermis, needle shape are needed to be effectively produced to assist HA entering the skin. Currently we used resin material to craft the mould, although needles can reasonable mechanical strength, the film is difficult to demould due to impermeability. After consulting the industry experts and relevant resources, we found that a material called polydimethylsiloxane (PDMS), which is a polymer organosilicon compound, may facilitate a better demoulding process
 +
<!--{cn}第三，产品的有效性是指最后的一个步骤-微针模板铸造技术，为了确保透明质酸微针能真正的进入表皮层，我们需要使透明质酸水凝胶具有一定针状形态才能将透明质酸渗入进皮肤内。目前我们使用树脂材料制作我们的模具，在脱模过程中无法完全脱落并且有许多残留，与此同时机械强度还并没有达到能刺入皮肤的程度。通过与行业专家和相关资源的咨询，我们发现聚二甲基硅氧烷(PDMS)是一种高分子有机硅化合物。可以确保更好地形成针状结构并具有更好的机械强度（ref）。由于其弹性好，在脱模过程中可以很容易地与模具分离。此外，在固化贴片上的贴板可能有助于脱模-->
 +
<sup>[11]</sup>
 +
. Therefore, we plan to try the PDMS mould in the next round of product fabrication testing.<!--{cn}。因此，我们计划在下一轮产品制造测试中切换到PDMS模具。-->
 +
</p>
 +
</div>
 +
</section>
 +
 +
<!--paragraph seven-->
 +
<section class="col-xs-12 col-sm-10">
 +
<p class="title"><span>Evaluation of Impact<!--{cn}影响评估--></span></p>
 +
<div class="card_title">
 +
<div class="col-xs-4 active">
 +
<span>Areas for Improvement<!--{cn}需要改进的地方--></span>
 +
</div>
 +
<div class="col-xs-4">
 +
<span>Environmental Impact<!--{cn}环境影响--></span>
 +
</div>
 +
<div class="col-xs-4">
 +
<span>Biosafety Impact<!--{cn}生物安全影响--></span>
 +
</div>
 +
<div class="clearfix"></div>
 +
</div>
 +
<div class="content card_content">
 +
<p>
 +
Microneedle technology provides a way to deliver active ingredients into deeper skin in a non-invasive and painless way. Currently, there are some challenges in the design and preparation of macromolecular microneedles. Because of the elastic characteristics of the skin, the latter will first deform and "surround" the microneedle when the microneedle pierces the skin, so the force applied to the microneedle may be greater than the force required to pierce the microneedle itself. In addition to skin characteristics, the geometrical shape, length, density and sharpness of microneedles influence the puncture performance of microneedles. And how to ensure the safety of the use of microneedles and how to improve the drug load and the efficiency of drug delivery.
 +
<!--{cn}微针以一种非侵入性和无痛的方式将活性成分注入更深的皮肤。目前，高分子微针的设计和制备方面存在着一些挑战。由于皮肤的弹性特征，微针在刺向皮肤时后者会先发生形变将微针“包围”，因此施加到微针的力可能大于本身需要刺穿微针的力。除了皮肤的特性，微针的几何形状、长度以及微针密度和锐度都会影响微针的穿刺性能。以及如何确保使用微针的安全性和如何提高药物的使用效率和提高药物的使用效率。-->
 +
</p>
 +
<p>
 +
Because HA is a natural polymer material that is highly biocompatible, its products can be degraded by a variety of microorganisms in the soil or humid environment after being abandoned. Therefore, it is an environmental friendly material, and its degradation products can form a benign cycle of nature after being returned to the nature, which is conducive to environmental protection. HA macromolecules are prone to degradation. Studies have shown that degradation is mainly caused by hydrolysis and reactive oxygen species on hydroxyl. Ultraviolet, ultrasonic, Co60 ray and some metal ions can degrade HA
 +
<!--{cn}由于透明质酸是一种具有高度生物相容性的天然高分子材料，它的产品被遗弃后，可以被土壤中的各种微生物降解或在潮湿环境中降解。因此，它是一种环境友好性的材料，它的降解产物可以在回归自然后形成良性循环，这有利于环境保护。透明质酸大分子易降解。研究表明，降解主要是由羟基的水解和活性氧引起的。紫外线、超声波、Co60射线和一些金属离子可以降解透明质酸-->
 +
<sup>[12]</sup>
 +
.<!--{cn}。-->
 +
</p>
 +
<p>
 +
In our final product, there is no bacteria at all. Although we use
 +
<!--{cn}在我们的最终产品中，根本就没有细菌。虽然我们使用-->
 +
<i>B.subtilis<!--{cn}枯草芽孢杆菌--></i>
 +
to manufacture HA, <!--{cn}来制造透明质酸，但-->
 +
<i>B.subtilis<!--{cn}枯草芽孢杆菌--></i>
 +
itself is a food-grade safe strain and HA is expressed extracellularly. After expression, we carry out the steps such as separation and purification of HA through ethanol precipitation to remove the impurities, including the remaining bacterial cells, from the cultural media, which is then heat inactivated (or autoclaved) to ensure the full elimination of live bacteria (refer to our
 +
<!--{cn}本身是一种食品级安全菌株并且透明质酸被表达在胞外。在表达后，我们将通过乙醇沉淀分离和纯化透明质酸，用于去除杂质，包括剩余的细菌细胞，然后是高温灭菌（或高压蒸汽灭菌处理），以确保完全消灭活细菌（参考我们的-->
 +
<a href="https://2018.igem.org/Team:SSTi-SZGD/Human_Practices">Integrated HP<!--{cn}综合HP--></a>
 +
). Before releasing to the market, the final product, HA microneedle, will also undergo a series of safety testing processes by cosmetic authorities. These tests include microbial contamination testing, new material testing, chemical and physical testing, etc. to ensure that our product is safe enough to be used by customers. Therefore, GMO application in our project is for manufacturing purpose only, it is very unlikely that the final product would incur any GMO concerns.
 +
<!--{cn}）。在向市场投放市场之前，最终产品透明质酸微针也将接受化妆品部门的一系列安全测试。这些测试包括微生物污染测试、新材料测试、化学和物理测试等，以确保我们的产品足够安全，供客户使用。因此，我们项目中的转基因的成果仅用于制造目的，最终产品不太可能引起任何转基因问题。-->
 +
</p>
 +
</div>
 +
</section>
 +
 +
<!--paragraph eight-->
 +
<section class="col-xs-12 col-sm-10">
 +
<p class="title"><span>Social Value<!--{cn}社会价值--></span></p>
 +
<div class="content">
 +
<p>
 +
In general, beauty needs are relatively concentrated, and for the middle-age population, effective beauty products can be used to delay aging. It may give people younger looking appearance therefor give them more confidence and security. On the other hand, for younger generation, a more vibrate skin condition may help improving their physical and mental well-being, in turn may also help with their career development thus social status. Overall speaking, cosmetics and skin care products may have a positive influence on social and economic development.<!--{cn}一般来说，美容需要相对集中，对于中年人来说，有效的美容产品可以用来延缓衰老。它可能会让看起来更年轻的人给他们更多的自信和安全感。另一方面，对于年轻的一代来说，可改善的皮肤状况可能有助于改善他们的身体和心理健康，反过来也可能有助于他们的职业发展从而获得社会地位。总的来说，化妆品和护肤品可能对社会和经济发展产生积极影响。-->
 +
</p>
 +
</div>
 +
</section>
 +
 +
<!--Reference-->
 +
<section class="Reference col-xs-12 col-sm-10">
 +
<p>
 +
<span class="col-xs-4 col-lg-5"></span>
 +
<span class="col-xs-4 col-lg-2">Reference</span>
 +
<span class="col-xs-4 col-lg-5"></span>
 +
<span class="clearfix"></span>
 +
</p>
 +
<p>
 +
<span>[1] </span>
 +
Yansi Li. Development status and strategy analysis of Chinese cosmetics industry[J].Modern Economic information,2015(04):394-396.
 +
</p>
 +
<p>
 +
<span>[2] </span>
 +
The next explosion in the beauty and cosmetics industry [DB/OL]. http://biz.jrj.com.cn/2018/08/28174825014773.shtml.
 +
</p>
 +
<p>
 +
<span>[3] </span>
 +
Yueshan Huang, Jing Xue. Research on the function and application of hyaluronic acid with different molecular weights[J]. Chinese Journal of Dialysis and Artificia | Organs,2011(02):10-13.
 +
</p>
 +
<p>
 +
<span>[4] </span>
 +
What are the risks of wrinkle removal by injection? [DB/OL]. https://jingyan.baidu.com/article/0964eca2d5f7f58284f53676.html.
 +
</p>
 +
<p>
 +
<span>[5] </span>
 +
Jing Xue, Shanyue Huang. Study on the function and application of different relative molecular weight hyaluronic acid[J]. Chinese Journal of Dialysis and Artificia,2010,04:22-25.
 +
</p>
 +
<p>
 +
<span>[6] </span>
 +
Kim Y C, Park J H,Prausnitz M R. Microneedles for drug and vaccine delivery[J].Pharmaceutics,2015,7(3):90-105.
 +
</p>
 +
<p>
 +
<span>[7] </span>
 +
Koen van der Maaden, Wim Jiskoot. Microneedle technologies for (trans)dermal drug and vaccine delivery[J]. Journal of Controlled Release,2012,161(02):645-655.
 +
</p>
 +
<p>
 +
<span>[8] </span>
 +
Dongyin Shi. Innovative development of medical microneedle[R]. Beijing: Beijing Yanjing electronics co. LTD, 2016:1-3.
 +
</p>
 +
<p>
 +
<span>[9] </span>
 +
Leiqi Wang. Design, developing and microstructure control of polymer microneedle[D].Beijing: Beijing University of Chemical Technology,2017:1-6.
 +
</p>
 +
<p>
 +
<span>[10] </span>
 +
Jie Zhang, Senfeng Ma. Matrix Materials and Their Composites for Dissolvable Microneedle Construction: a Review[J]. Material review,2017,31(19):129-134.
 +
</p>
 +
<p>
 +
<span>[11] </span>
 +
Qilei Wang, Dandan Zhu, Yang Chen. A fabrication method of microneedle molds with controlled microstructures[J]. Materials science,2016:135-142.
 +
</p>
 +
<p>
 +
<span>[12] </span>
 +
Yun He. Degradation of hyaluronic acid[D]. Nanjing, Nanjing university of science and technology, 2010.1-8.
 +
</p>
 +
</section>
 +
 +
</div>
 +
 +
</div>
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Latest revision as of 02:40, 16 November 2018

What's the problem & Our vision?

After more than twenty years of rapid development, China's cosmetics market, known as "beauty economy", has become the world's second largest cosmetics market after the United States [1] . According to the "analysis of market size and development trend of China's cosmetics industry in 2017" [2] , CAGR (Annual compound growth rate) of China's cosmetics industry was 9.1% in the past five years, far higher than the global aver age CAGR of 4.1%. It is estimated that the market size of China's cosmetics industry could reach 490.6 billion in 2019. (see Fig.1) From the current situation of the cosmetics industry, China's cosmetics market has a broad prospect.

Fig.1. Analysis chart of development trend of Chinese cosmetic market.

At present, as the living standard improves, demand for anti-aging products is growing, and the use of natural polymer ingredients in cosmetics to promote skin repair and wrinkle removal increases every year. Among the commonly used polymer ingredients, hyaluronic acid (HA), a type of macromolecular mucopolysaccharide, is extensively used in cosmetics due to its excellent permeability, moisturizing, and biocompatibility properties, so as to improve skin humidity and achieve the effects of skin rejuvenation.

The biological activity and water retention effects of hyaluronic acid is directly related to its relative molecular weight (Mr). High and middle molecular weight HA (Mr≥1-2×106 Da) with great viscoelasticity, lubrication, and moisturizing effects are widely used in cosmetics, while low molecular weight HA (Mr≤1×104 Da) has potential anti-tumor effects, and promotes wound healing and immune regulation [3] .

HA has prominent effects on promoting tissue remodeling and reducing scar formation, thereby it is a star material in cosmetic products. Most products on the market containing HA and its derivative sodium hyaluronate are facial masks and cream formulations. Although these products make skin appear softer and smoother, due to the barrier effect of skin epidermis, it is difficult for active ingredients to efficiently penetrate through the stratum corneum and release into the deeper skin for a long-term effect, unless using surgical methods (i.e. injection). Surgical methods, on the other hand, usually result in facial bruising, skin necrosis and intense pain, which could seriously affect facial nerve system and result in rigid facial expressions. Injection may also trigger immune reactions, resulting to temporary swelling, headaches, mild nausea and minor numbness [4] . Therefore, searching for an alternative method for effectively and safely delivering HA into skin dermis has become necessary.

In addition, compare to high molecular weight HA, low molecular weight HA can be more efficiently absorbed across skin epidermis. However, its moisturizing and viscoelastic properties are far inferior to high molecular weight HA [5] .

Thereby, we endeavor to develop a new cosmetic application method that combines the advantages of high and low molecular weight HA, as well as eliminating the tedious and potentially dangerous operation of injection and surgery, to achieve lasting effects of skin rejuvenation and wrinkle removal.

Comparison of products in the market

Based on the understanding of the current cosmetic market, and refer to relevant resources, we came across a new method that has the potential to replace the traditional injection approach -- "microneedle delivery system", which represents a new stage of technology development in cosmetics industry. The main advantage of microneedle system is that it can pierce through the skin in a non-invasive and painless way, and help with the efficient delivery of macromolecular ingredients. It is safer than surgery or injections, while being more effective than ordinary moisturizing cream or masks.

The current available microneedle delivery products are made of silicon wafer, metal materials or natural sugars [6] . Silicon wafer based microneedles, fabricated using MEMS (micro-electromechanical system) microfabrication technology, are sharper than those made of polymer, sugar or metal [7] . It is conducive to penetrate through the skin epidermis and reducing discomfort. However, because silicon absorbs proteins, when use in deeper skin, white blood cells are drawn to the material to induce stress response on the affected area [7] . Microneedles made of silicon wafer (see Fig.2) also have drawbacks such as complex preparation procedures, high processing cost and requirements, and fragile proposition. The nature of the material can lead to easy breakage of the tips under the skin, combining with a low biocompatibility property, tip residues can result to skin infection [8] .

Metal based microneedles (see Fig.2) , generally made of stainless steel, titanium, nickel, etc., are fabricated by laser cutting, laser etching and wet etching [8] . Metal material, usually used in combination with serum, can cause painful sensation when use, and frequent use may cause pore enlargement. Also, because metal-based microneedles are usually re-used, it may lead to the contamination of blood-transferrable diseases, i.e. AIDS, hepatitis and so on [8] . With regards to industrial production, metal based microneedle, with its relatively complex preparation requirement, is not prone to mass production. Sugar based microneedles are usually prepared from maltose, trehalose, sucrose, fructose, etc. These sugar materials require stringent preparation and storage conditions. If not stored properly, they can absorb moisture easily and result to reduced hardness [9]

In recent years, the preparation of microneedles with natural and degradable polymer biomaterials has become a hot topic. (see Fig.2) There have been a variety of raw materials, i.e. polyvinyl alcohol, polylactic acid, chitosan, carboxymethylcellulose, HA, silk protein, etc. being used in microneedle fabrication [9] . Among them, HA, with its excellent moisturizing property, biocompatibility, and relatively simple preparation method, has become a popular microneedle biomaterial.

Fig.2.(A) silicon wafer microneedle, (B) metal microneedle, (C) macromolecule microneedle.

There are existing HA micro-needle eye patch products on the market, for example, Quanis(R) from Japan and Acropass(R) from South Korea. (see Fig.3) The manufacturing process for these products is air blast stretching technology. In this way, microneedles are of uniform shape, but with weak mechanical strength and short in needle size, which hamper the efficient penetration into the skin. In addition, these products are used in combination with the water retention serum to assist the better absorption of the serum. In this regard, microneedle is only used for its auxiliary function, which greatly undermines its value and potential.

Figure.3. Various types of microneedles in current market

How to change the situation?

We would like to formulate a new type of HA based microneedle with both the penetration function and moisturizing ability, that is, these microneedles are made of HA material with sufficient strength to pierce through skin epidermis, then release HA molecules to exert the water retention effect.

HA is one of the most functional macromolecules in nature. As an important part of the natural extracellular matrix, HA plays an important role in various biological processes. However, because of its easy degradation and poor mechanical properties, natural HA is not suitable for microneedle preparation. Compared with natural HA, chemical cross-linking of HA can efficiently enhance its stability, mechanical strength, in-situ swelling ability of the microneedle within skin, and decrease its biodegradability. Also, as cross-linking procedures result to a hydrogel like material with stable 3D structures (see Fig.4) , it is better suitable for crafting microneedles.

Fig.4. Hyaluronic acid cross-linking

At present, the mainstream chemical cross-linking agents for HA are diethylsulfone (DVS) and 1, 4-butanediol diglycidyl ether (BDDE). DVS, although widely used in R&D, has high cytotoxicity. Not only this toxic substance is likely to be accumulated in the body after implantation, but also it may affect normal tissue growth due to calcification of the implant. In comparison, BDDE is considered to be the mostly commonly used cross-linking agent in preparation of cosmetic HA fillers. BDDE is biodegradable, much less toxic and more reactive than DVS, thereby safer for biomedical applications.

How to achieve it?

  1. We engineered Bacillus subtilis bacteria to produce HA (HMW and LMW separately) by transgenic methods. Once the secreted raw HA are separated and purified by ethanol precipitation, HA molecules are freeze-dried to form powder as a starter material for the following cross-linking procedures.
  2. We cross-linked LMW HA with less toxic and better reactive crosslinking agent, BDDE, to obtain a hydrogel form of HA. This hydrogel containing HA nanoparticles possesses stable structure, improved mechanical strength and would be less sensitive to enzymatic degradation.
  3. Cross-linked HA and HMW HA molecules are blended in certain ratio to obtain a mixture, which is then poured into the a specially designed mould for microneedle fabrication. Our mould for microneedle fabrication is a 3D printed photosensitive resin, which is a high-strength and high-temperature proof material with features of energy saving, low pollution, fast curing speed and high production efficiency.

Production formulation

HA crosslinking process

Cross-linked HA (cHA) reagent solution was prepared by mixing 200μl of 1, 4-butanediol diglycidyl ether (BDDE) into 9.8ml of 0.25M NaOH (pH13). Approximately 1.0g of HA powder was added to the cHA reagent solution and mixed thoroughly at 40 ℃ for 2h. The prepared hydrogel was ground, squeezed out and screened with 170 mesh sieve to get smaller particles.

Preparation of HA microneedle

HA molecules and crosslinked HA hydrogel are mixed and dissolved in ultra-pure water in different proportions, and the viscous polymer solution is mixed uniformly with magnetic agitator at room temperature. Apply the viscous solution to the mold under vacuum pressure and use the blade to peel off the remaining solution. After curing at room temperature overnight, the transparent microneedle patch is successfully prepared. (see Fig.5)

Fig.5. Flow chart of preparation of microneedle

Characterization of microneedle

In order to make HA more effectively absorbed by the skin, we crafted a mould with cone shaped needles. This particular shape is believed to provide the needles with sufficient mechanical strength and stability, which enables HA entering into the deeper skin efficiently. (see HA-MN results) Given sufficient reaction time, eventually the entire patch would be absorbed completely by the skin with no waste produced. In case of shorter reaction time, the remaining patch can be disposed as ordinary kitchen garbage to undergo natural degradation.

In the future, we plan to craft the HA microneedle patches into several shapes to accommodate different needs.

Shape Purpose
Triangle Used for frown lines, crow's-feet
Crescent Used for nasolabial folds or surrounding eye area
Rectangle Used for forehead wrinkles

Product Design Considerations

We have three aspects to consider in the product design process: product safety, product material and product effectiveness.

Firstly, product safety aspect is related to the source of HA. Most of HA material and its derivatives used in the market are of Streptococcus origin . Streptococcus strain is a conditional pathogenic bacterium that poses potential human and environmental risks. Because of it endogenous endotoxin, its by-products, i.e. HA, are likely to carry the toxin. In the current project, we use food-grade B.subtilis to produce HA. This bacterium strain is well studied with genome fully sequenced, has no endotoxin, and requires low nutrition to reduce production cost. Therefore the raw material for our product is of less biosafety concern.

Secondly, product material refers to the cross-linking process of HA. Our HA microneedle using cross-linked low molecular weight (~17 kDa) HA to obtain a hydrogel. Because the high molecular weight (~1500 kDa) HA has longer polymer chain structure, which when cross-linked, results to more coiled structure formation and greater self-association. This somewhat “packed” structure is unstable and unable to form a homogeneous hydrogel. In contrast, low molecular weight HA, because of its shorter polymer chain structure, has a greater chance of forming inter-molecular bonds, so that hydrogel with stable 3-D structure is more likely to be formed[10]. (see Fig.6)

Fig.6. The cross-linking state of hyaluronic acid

Thirdly, the product effectiveness is decided by microneedle fabrication technology. In order for the microneedle to enter the skin epidermis, needle shape are needed to be effectively produced to assist HA entering the skin. Currently we used resin material to craft the mould, although needles can reasonable mechanical strength, the film is difficult to demould due to impermeability. After consulting the industry experts and relevant resources, we found that a material called polydimethylsiloxane (PDMS), which is a polymer organosilicon compound, may facilitate a better demoulding process [11] . Therefore, we plan to try the PDMS mould in the next round of product fabrication testing.

Evaluation of Impact

Areas for Improvement
Environmental Impact
Biosafety Impact

Microneedle technology provides a way to deliver active ingredients into deeper skin in a non-invasive and painless way. Currently, there are some challenges in the design and preparation of macromolecular microneedles. Because of the elastic characteristics of the skin, the latter will first deform and "surround" the microneedle when the microneedle pierces the skin, so the force applied to the microneedle may be greater than the force required to pierce the microneedle itself. In addition to skin characteristics, the geometrical shape, length, density and sharpness of microneedles influence the puncture performance of microneedles. And how to ensure the safety of the use of microneedles and how to improve the drug load and the efficiency of drug delivery.

Because HA is a natural polymer material that is highly biocompatible, its products can be degraded by a variety of microorganisms in the soil or humid environment after being abandoned. Therefore, it is an environmental friendly material, and its degradation products can form a benign cycle of nature after being returned to the nature, which is conducive to environmental protection. HA macromolecules are prone to degradation. Studies have shown that degradation is mainly caused by hydrolysis and reactive oxygen species on hydroxyl. Ultraviolet, ultrasonic, Co60 ray and some metal ions can degrade HA [12] .

In our final product, there is no bacteria at all. Although we use B.subtilis to manufacture HA, B.subtilis itself is a food-grade safe strain and HA is expressed extracellularly. After expression, we carry out the steps such as separation and purification of HA through ethanol precipitation to remove the impurities, including the remaining bacterial cells, from the cultural media, which is then heat inactivated (or autoclaved) to ensure the full elimination of live bacteria (refer to our Integrated HP ). Before releasing to the market, the final product, HA microneedle, will also undergo a series of safety testing processes by cosmetic authorities. These tests include microbial contamination testing, new material testing, chemical and physical testing, etc. to ensure that our product is safe enough to be used by customers. Therefore, GMO application in our project is for manufacturing purpose only, it is very unlikely that the final product would incur any GMO concerns.

Social Value

In general, beauty needs are relatively concentrated, and for the middle-age population, effective beauty products can be used to delay aging. It may give people younger looking appearance therefor give them more confidence and security. On the other hand, for younger generation, a more vibrate skin condition may help improving their physical and mental well-being, in turn may also help with their career development thus social status. Overall speaking, cosmetics and skin care products may have a positive influence on social and economic development.

Reference

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[2] The next explosion in the beauty and cosmetics industry [DB/OL]. http://biz.jrj.com.cn/2018/08/28174825014773.shtml.

[3] Yueshan Huang, Jing Xue. Research on the function and application of hyaluronic acid with different molecular weights[J]. Chinese Journal of Dialysis and Artificia | Organs,2011(02):10-13.

[4] What are the risks of wrinkle removal by injection? [DB/OL]. https://jingyan.baidu.com/article/0964eca2d5f7f58284f53676.html.

[5] Jing Xue, Shanyue Huang. Study on the function and application of different relative molecular weight hyaluronic acid[J]. Chinese Journal of Dialysis and Artificia,2010,04:22-25.

[6] Kim Y C, Park J H,Prausnitz M R. Microneedles for drug and vaccine delivery[J].Pharmaceutics,2015,7(3):90-105.

[7] Koen van der Maaden, Wim Jiskoot. Microneedle technologies for (trans)dermal drug and vaccine delivery[J]. Journal of Controlled Release,2012,161(02):645-655.

[8] Dongyin Shi. Innovative development of medical microneedle[R]. Beijing: Beijing Yanjing electronics co. LTD, 2016:1-3.

[9] Leiqi Wang. Design, developing and microstructure control of polymer microneedle[D].Beijing: Beijing University of Chemical Technology,2017:1-6.

[10] Jie Zhang, Senfeng Ma. Matrix Materials and Their Composites for Dissolvable Microneedle Construction: a Review[J]. Material review,2017,31(19):129-134.

[11] Qilei Wang, Dandan Zhu, Yang Chen. A fabrication method of microneedle molds with controlled microstructures[J]. Materials science,2016:135-142.

[12] Yun He. Degradation of hyaluronic acid[D]. Nanjing, Nanjing university of science and technology, 2010.1-8.

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Copyright © 2018 SSTi-SZGD All Rights Reserved.