Synthesis of controllable carboxylated polystyrene microspheres and its application in the diffusion of in-vitro diagnostic chips

In order to develop the in-vitro diagnostic chips with dry chemical methods that have good diffusion performance, high accuracy of test results, and good reproducibility, the synthesis conditions of carboxylated polystyrene(PS) microspheres with uniform and controllable size, and strong surface reactivity is one of the key factors. By changing the solvent type, reaction temperature, and monomer concentration, we can control the particle size of PS microspheres. The effects of solvent type and acrylic acid concentration on the carboxyl content on the microsphere surfaces were investigated. The effect of surfactant (TX100) and stirring time on diffusion of the diffusion layer were proposed. The results showed that PS microspheres with uniform particle size were prepared with ethanol at the reaction temperature of 70°C and monomer concentration of 20 wt%. The effect of the solvent on the surface carboxyl content of PS microspheres was significant. With pentanol as the solvent, the carboxyl group content on the surface of the microspheres reached 33.9mg/g. When the stirring time is 50 min, TX100 is added as asurfactant, and the prepared diffusion layer has the best effect on diffusion.