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Steven Taniselass
Preferred name
Steven Taniselass
Official Name
Steven, Taniselass
Alternative Name
Taniselass, S.
Taniselas, S.
Taniselass, Steven
Main Affiliation
Scopus Author ID
36998664900
Researcher ID
EAA-5755-2022
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PublicationImpedimetric-based biosensor for Cardiac Troponin 1 detection: sensing strategy aided by Hybrid rGO and Gold Interdigitated ElectrodeCardiovascular diseases (CVD) are the number one cause of death among the noncommunicable diseases globally. CVD are referred to diseases that associated with the abnormalities of blood flow in heart and often related with ‘heart attack’ condition or in clinical term as an acute myocardial infarction (AMI). Cardiac Troponin I (cTnI) biomarker is widely accepted as gold standard for AMI recognition due to its high specificity. Hence, the need for portable and highly sensitive sensor with fast detection is utmost required to diagnose AMI for fast treatments. Herein, a label-free impedimetric-based cTnI immunosensors were fabricated and their analytical performances were assessed and reported in this thesis. Reduced graphene oxide (rGO) and gold interdigitated electrode (Au-IDE) were employed to develop the immunosensors. The research work is divided into two main sections; first is to obtain a uniform deposition of rGO through single-droplet drop-casting technique and second is to fabricate the cTnI immunosensor aided by rGO. The deposition results revealed the method-3 involving post-sonication technique produces a large and self-assembled of rGO nanoflakes through single-droplet drop-casting without the use of any chemical solvent. Furthermore, the rGO modified Au-IDE devices show an excellent electron mobility, whereby the electrical conductivity was enhanced approximately ~1000-fold compared to the bare devices. Thus, the as-prepared rGO suspension was used to fabricate the immunosensors. Four different surface modification strategies on respective bioelectrodes mediated by the as-prepared rGO suspension were investigated. Electrochemical impedance spectroscopy (EIS) was performed to characterize the immunosensors by sweeping frequencies from 0.1 - 500 kHz at a small AC voltage (25 mV). Results revealed that one of the four immunosensors developed through strategy-4 shows an excellent analytical performance for the cTnI antigen detection in spiked buffer and human serum. A potential surface functionalization mediated by rGO basal plane functional groups was postulated based on XPS and FTIR analyses. The as-fabricated immunosensor showed a wide linear range (10 ag/mL – 100 ng/mL) of cTnI antigen detection in human serum with a linear regression coefficient (R2) of 0.9716 and the lowest analytes detected was 10 ag/mL, whereby it shows highly selective and sensitive trait. The immunosensor also showed a fast-detection that only required 5 minutes for probe and targets binding and stable for nine days. The bioelectrodes were highly reproducible. Hence, such an electrode sensing surface modifications strategy can be further extrapolated for later applications in various biomarker mediated disease diagnoses.