Preparation of nematic liquid crystal microspheres via microfluidic approach for detection of phospholipase A1: a biomarker of Alzheimer’s disease

In this study, we present a biosensor that employs a microfluidic approach to fabricate nematic liquid crystal (NLC) microspheres for the detection of phospholipase A1 (PLA1), a biomarker linked to Alzheimer’s disease (AD). We created uniform-diameter NLC microspheres utilizing a custom-designed microfluidic chip and functionalized them with phosphatidylcholine, which facilitates a radial arrangement. Following this, the NLC microspheres underwent a transition from a radial to a bipolar arrangement due to the hydrolysis of PC by PLA1. This method allows for direct observation of the detection process using a polarizing microscope. Image binarization is subsequently applied to enhance detection sensitivity, achieving a detection limit for PLA1 of 400 pg/μL. Furthermore, the detection time is reduced by more than twelve-fold compared with traditional methods. The rapid response capability of NLC microspheres demonstrates significant potential for the detection of various diseases and biomarkers. Our research establishes a foundation for the further development of a detection platform for the AD marker PLA1, paving the way for the creation of a low-cost, rapid, and portable diagnostic tool.