SERS Based Biosensor to Detect Cardiac Biomarkers
Myocardial infarction (MI) is one of the most common causes of death in the world. The measurement of cardiac biomarkers plays a key role in the diagnosis process, and improvements in this field could have a significant positive impact in the health of patients. Therefore, the development of fast, sensitive, and precise technologies to measure cardiac biomarkers is of great interest.
Research Goal
This project focuses in the development of a surface enhanced Raman spectroscopy (SERS)-based assay to detect cardiac biomarkers such as cardiac troponin I, FABP, and myoglobin. Several SERS active nanoparticles are synthesized and functionalized to use them in assays. In addition, different platforms to implement the assay at the point of care are designed and tested. The factors that affect the assay performance are optimized to obtain the necessary requirements for diagnosis.
SERS Based Biosensor to Detect Cardiac Stress
Research Goal
The aim of the project is to develop a platform for detecting congestive heart failure diseases. The ventricular walls of the heart produces B-type Natriuretic Peptide (BNP) in response to an increased heart stress. Therefore, measuring BNP levels in the blood can be a good indicator of cardiac stress. The project involves the development and optimization of Surface Enhanced Raman Scattering (SERS) based assays for BNP detection.
SERS Based Biosensor to Detect Blood Toxins
BPA & DEHP Biomarker
Because of the widespread use of plastics in daily life, humans are frequently exposed to different types of additives exists in plastic products. Bisphenol A (BPA) is the monomer of an epoxy resin commonly used in plastic food and beverage packaging, and can be toxic to the endocrine system when exposed to humans. Bis(2-ethylhexyl) phthalate, another popularly used plastic additives, mainly exists in PVC product. DEHP was reported to cause Premature breast development, asthma, and reduced quality of human semen. Thus, developing a sensitive method to reliably monitor levels of those bio-toxins in human body can help determine the body’s burden with the toxin, and the metabolism of the toxin in human body.
Research Goal
In our lab, surface enhanced Raman spectroscopy (SERS) is used to realize the sensitive detection of those environmental toxins. Aptamers that specifically bind with target toxin molecules are designed, and then utilized as the recognition element in the assay. Different nanoparticles are explored to get optimal SERS signal. Raman reporter molecules (RRM) are conjugated on the surface of the nanoparticle to provide SERS signal with specific peaks and strong intensity. To sensitively detect BPA, we have designed an assay using a functional SERS nanoprobe with specific affinity to the BPA aptamer, and another assay using the formation of assemblies of plasmonic nanoparticles and magnetic nanoparticle. And for sensitive detection of DEHP, we have designed an assay using formation of assemblies of two plasmonic nanoparticles, and an improved assay using silica encapsulated nanoprobe with specific affinity to the BPA aptamer. We will continue to explore detection of other biomarkers and environmental toxins, and develop an integrated platform for multiple analytes detection.
SERS Based Biosensor to Detect Oral Cancer
Research Goal
Our research group focus on the design of a non-invasive, early detection technology for oral cancer. S100 calcium binding protein P (S100P) mRNA found in whole saliva is a potential biomarker for detection of oral cancer. A Surface enhanced Raman spectroscopy (SERS) based assay for the sensitive and rapid detection of S100P was designed and developed. Gold nanoparticles (AuNPs) were conjugated with two unique oligomers which would bind to different moieties of the target mRNA. A Raman reporter molecule, malachite green isothiocyanate (MGITC), is conjugated to one of the oligomer-conjugated-AuNPs. The hybridization of S100P target to oligomer-conjugated AuNPs forms a sandwich-assay which results in a signification enhancement of the MGITC Raman signal. This project is in collaboration with Dr. Yi-Shing Cheng at Texas A&M University – Baylor College of Dentistry.
SERS Based Biosensor to Detect Disease of the Gut
Research Goal
The amino acid, L- Citrulline, has been reported as a potential biomarker of gut function. Our research focus on using paper fluidics to quantify the concentration of citrulline in blood samples. The assay developed by our research group utilizes a fluorescently labelled aptamer, with a binding affinity to citrulline, conjugated on the surface of gold nanoparticles. In the presence of varying concentrations of citrulline, the aptamer changes its conformation allowing for the distance between the fluorescent dye (also a Raman reporter molecule) and the metal surface to change. A Surface enhanced Raman spectroscopy (SERS) and Fluorescence spectroscopy can then be used to monitoring changes in signal based on changes in concentration of the blood biomarker.