Giant magnetoresistive-based biosensing probe station system for multiplex protein assays.

In this study, a sensitive immune-biosensing system capable of multiplexed, real-time electrical readout was developed based on giant magnetoresistive (GMR) sensor array to detect a panel of protein biomarkers simultaneously. PAPP-A, PCSK9, and ST2 have been regarded as promising candidate biomarkers for cardiovascular diseases. Early detection of multiple biomarkers for a disease could enable accurate prediction of a disease risk. 64 nano-size GMR sensors were assembled onto one 16 mm × 16 mm chip with a reaction well, and they could work independently and be monitored simultaneously. A detect limit of 40 pg/mL for ST2 antigen had been achieved, and the dynamic ranges for the three proteins detection were up to four orders of magnitude. The GMR sensing platform was also selective enough to be directly used in serum samples. In addition, a lab-based probe station has been designed to implement quick lab-on-a-chip experiments instead of wire bonding. It has a potential application in clinical biomarkers identification and screening, and can be extended to fit other biosensing schemes.