Multifunctional Polystyrene Core/Silica Shell Microparticles with Antifouling Properties for Bead-Based Multiplexed...

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Commercial bead-based assays often use polystyrene particles, which have limitations like hydrophobic surfaces causing nonspecific adsorption.
• Existing functionalization methods for polystyrene beads are restricted by the reactivity of incorporated groups, limiting surface modification.
• Nonspecific binding necessitates multiple washing steps and additives in bioanalytical assays, increasing complexity and cost.

Purpose of the Study:

• To overcome limitations of traditional polystyrene beads by developing novel hybrid core/shell particles.
• To create multifunctional microparticles for improved bead-based assays with reduced nonspecific binding and simplified protocols.
• To demonstrate a wash-free competitive fluorescence immunoassay for caffeine detection using the developed hybrid particles.

Main Methods:

• Synthesized monodisperse polystyrene (PS) core/silica (SiO2) shell particles (SiO2@PS) with encapsulated BODIPY dyes for multiplexing.
• Functionalized the silica shell with an aminopropyltriethoxysilane (APTES) and polyethylene glycol silane (PEGS) blend in a single step.
• Coupled a caffeine derivative (hapten) to the amino groups on the silica shell and utilized PEG for antifouling properties.

Main Results:

• Created 5-plex arrays using different concentrations of BODIPY dyes within the PS core, detectable in two cytometer channels.
• The PEG moiety on the silica shell effectively suppressed nonspecific antibody binding, imparting antifouling characteristics.
• Developed a selective, wash-free competitive fluorescence immunoassay for caffeine detection in beverages, demonstrating proof of concept.

Conclusions:

• Silica-shelled polystyrene (SiO2@PS) hybrid particles offer a versatile platform overcoming limitations of conventional polystyrene beads.
• The single-step functionalization strategy provides multifunctional surfaces with both antigen attachment sites and antifouling properties.
• The developed wash-free immunoassay demonstrates the potential of these hybrid particles for simplified and efficient bioanalytical applications.