Summary of Description

Necessity of Quick & Simple Diagnosis of Heart Failure

Heart failure is a major public health problem, with more than 5.8 million patients in the United States and 40 million worldwide. Common causes of heart failure include heart attack, hypertension, atrial fibrillation, excessive alcohol use, infection, and myocardial infarction. Early diagnosis of heart failure is essential for successful treatment of the disease. However, current diagnosis of heart failure patients takes considerable time from initial sampling to detection results due to sample transportation time and operating costs. Also, there is no convenient and affordable service system for continuous monitoring of patient status.

Why Biosensor for Diagnosis?

Portable biosensors that enable on-site analysis of samples are very useful for effective diagnosis and monitoring of heart failure patients. Among them, electrochemical immunosensors have several advantages of simplicity, inexpensive cost, accuracy, and high sensitivity.

Our Strategy

It is necessary to produce effective, high sensitivity, and low-cost immunosensors. The efficient immobilization of antibodies on a sensor is important for designing immunosensors. Self-assembled monolayers (SAMs) method is widely used to immobilize antibodies on gold surfaces, but the chemical method is very complex and it takes a long time. Therefore, a simpler method of immobilizing antibodies the gold surfaces is necessary.

To overcome this problem, we used synthetic biology method to produce a novel fusion protein of gold binding polypeptides (GBP)–protein G (ProG) as a crosslinker for effective immobilization of antibodies the gold surfaces. The following are the procedures:

1. Recombinant Plasmid Containing GBP-ProG Gene to Produce GBP-ProG Fusion Protein

2. Fabrication of Interdigitated Array (IDA) Gold Electrode to Create an Electrochemical Microfluidic Chip

3. GBP-ProG Fusion Protein Self-Immobilization to IDA Electrode

The resulting GBP-ProG fusion protein will be self-immobilized directly on the gold surface through GBP portion. Fc region region of the antibodies will be bound to the ProG domain.

This will be developed for the detection of human N-terminal prohormone of brain natriuretic peptide (NTproBNP) in the early diagnosis of heart failure.

As a result, we expect that the GBP-ProG protein to be a crosslinker for effective immobilization of antibodies onto the gold surfaces without any surface chemical modification.

Application

This electrochemical immunosensor can efficiently diagnose and monitor heart failure cases, which have increased worldwide, to reduce the time loss and mortality rates of individuals.