Biosensors & Bioelectronics

Biography

Biography: Elisabete Fernandes

Abstract

Cancer, stroke and cardiovascular diseases are excellent examples of large public health problems requiring an early detection system that led scientific communities focus their interests on the biosensing area. Integrated spintronic biochip platforms are being developed for pointofcare (POC) diagnostic/prognostic applications. Here we report a biochip platform comprising 30 spin-valve (SV) sensors separated in six groups of 4 bioactive sensors plus a reference sensor. This platform join all the advantages of a magnetoresistive based biochip sensitivity, fast response, no signal interference with the possibility to perform an integrated sample pretreatment (separation, labelling and amplification) in a miniaturized, portable, lab on a chip electronically assisted platform. This work presents the potential of this technology on different bioanalytical applications reported in several publications (e.g. proteins, pathogens, DNA identification and polymorphism), emphasizing a multiplex detection system that has being performed to detect a panel of biomarkers present in human serum to predict brain ischemia. Our detection strategy is based on multiple “sandwich” immunoassays over the chip area. The biological targets are initially labelled in serum by using antibodyanchored magnetic nanoparticles (MNPs) of 250nm and loaded through microfluidics onto an array of SV sensors, where the specific probes (antibodies) are immobilized. Upon probe/target recognition, and a washing step to remove unspecifically bound biomolecules, the final immobilized target is quantified. The full assay takes around 45 minutes. Calibration curves are being established to define the detection limits for each of the six stroke’s biomarkers, and we have reached the minimum detection limit of 4 μg/mL for Fibronectin, which is in accordance with the cutoff value defined for stroke patients. Taking the advantages of the magnetic attraction that allows to concentrate the target over the probe sites, limits of detection in the nanogram range are further expected.