Spanish 
Chinese 
Russian 
German 
French 
Japanese 
Portuguese 
Hindi A magnetoresistive biochip platform and its bioanalytical applications
Fernandes E, Martins V C, Dias T, Germano J, Cardoso F A, Sobrino T, Cardoso S and Freitas P P
1International Iberian Nanotechnology Laboratory, Portugal 2INESC-MN, Portugal 3University of Santiago de Compostela, Spain
: J Electr Eng Electron Technol
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 point of care (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 antibody anchored magnetic nanoparticles (MNPs) of 250 nm 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 concentrating the target over the probe sites, limits of detection in the nanogram range are further expected
Biography
