A Novel Magnetoelastic Biosensor With Flexible TbDyFe Film as Sensing Materials for Osteoarthritis Marker MMP-3 Detection

A new design of flexible magnetoelastic (ME) biosensor based on TbDyFe/polystyrene-poly (ethylene-butylene)-polystyrene block copolymer (SEBS) film for the osteoarthritis (OA) marker matrix metalloproteinase 3 (MMP-3) detection is presented. This article studied a novel flexible ME film to replace the traditional rigid substrate for biosensors. The magnetostrictive material of TbDyFe was mixed homogeneously with paraffin solution to fabricate TbDyFe fluid, which was reacted at high temperature with SEBS in a certain ratio to prepare the film. TbDyFe/SEBS films were used as substrates for the immobilization of MMP-3 antibodies. Specific binding of antibodies to MMP-3 antigens generated compressive stress on the substrate surface, which in turn led to changes in magnetic permeability and impedance. To improve the sensitivity of the biosensor, the TbDyFe doping concentration was optimized and the magnetic response performance of the TbDyFe/SEBS composite film was measured. The results show that this assay is capable of detecting concentrations of MMP-3 between 0.76 and 10000 ng $\cdot $ mL−1 with a detection limit of 0.76 ng $\cdot $ mL−1, covering the range of clinical tests required for the diagnosis of OA. This novel flexible ME biosensor provides a viable method for the diagnosis and monitoring of OA.