An organic substrate based magnetoresistive sensor for rapid bacteria detection

A point-of-care diagnostic system has been developed to detect pathogenic bacteria rapidly, of which system contains a magnetoresistive (MR) sensor in cooperation with a magnetic bead coated by specific antibody against bacteria. MR sensor with Teflon passivation layer has been fabricated on organic substrate, being flexible and low cost material, and passivated by Teflon layer for maintaining flexibility. The performance of the MR sensor is demonstrated using Magnetospirillum magneticum AMB-1 and its detection limit was found to be 1.3×10⁸cells/ml. Further, Escherichia coli is captured by immobilised anti-E. coli antibodies on the surface of the sensor and detected using magnetic bead labelled with anti-E. coli antibody. The detection limit of E. coli was found to be 1.2×10³cells/ml. The technique is simple, rapid, sensitive and does not require pre-treatment of the sample and can detect a variety of microorganisms. The high performance of sensor fabricated on flexible organic substrate may allow its future use for bio-applications in implantable types of devices.