Fiber optic surface plasmon resonance sensor for high-sensitivity detection of MMP10, a diagnostic target for Alzheimer's disease.

The existing in vivo detection methods for Alzheimer's disease (AD) diagnostic targets have two problems of inability to detect in real time and poor recognition of ligand biocompatibility, making it difficult to effectively achieve early and rapid screening for AD. This article proposes a fiber optic surface plasmon resonance (SPR) sensor with a surface-modified quercetin ligand, which successfully detects what we believe to be a novel early AD diagnostic target matrix metalloproteinase-10 (MMP10) in artificial cerebrospinal fluid. It has the characteristics of real-time detection and good biocompatibility. By using molecular docking technology to simulate the molecular binding mechanism between quercetin and MMP10, it was confirmed that the binding free energy of the two was as high as -9.0 kcal/mol. A reflective SPR sensor functionalized with quercetin was constructed using a plastic-coated step-index multimode fiber, which was inserted into a medical needle to achieve concentration detection of MMP10 in a simulated cerebrospinal fluid environment in the subarachnoid space. Experimental data indicate that the detection sensitivity of the sensor is 7.06 nm/lg (pg/mL), with a detection limit of 1.41 pg/mL, which meets the clinical detection standards, and the recognition ligand is harmless to the human body. This is expected to be used for real-time detection of early AD diagnostic targets in vivo, providing new ideas for early and rapid screening of AD.