Polystyrene Core–Silica Shell Particles with Defined Nanoarchitectures as a Versatile Platform for Suspension Array Technology

Abstract

The need for rapid and high-throughput screening in analytical laboratories has led to significant growth in interest in suspension array technologies (SATs), especially with regard to cytometric assays targeting a low to medium number of analytes. Such SAT or bead-based assays rely on spherical objects that constitute the analytical platform. Usually, functionalized polymer or silica (SiO2) microbeads are used which each have distinct advantages and drawbacks. In this paper, we present a straightforward synthetic route to highly monodisperse SiO2-coated polystyrene core-shell (CS) beads for SAT with controllable architectures from smooth to raspberry- and multilayer-like shells by varying the molecular weight of poly(vinylpyrrolidone) (PVP), which was used as the stabilizer of the cores. The combination of both organic polymer core and a structurally controlled inorganic SiO2 shell in one hybrid particle holds great promises for flexible next-generation design of the spherical platform. The particles were characterized by electron microscopy (SEM, T-SEM, and TEM), thermogravimetry, flow cytometry, and nitrogen adsorption/desorption, offering comprehensive information on the composition, size, structure, and surface area. All particles show ideal cytometric detection patterns and facile handling due to the hybrid structure. The beads are endowed with straightforward modification possibilities through the defined SiO2 shells. We successfully implemented the particles in fluorometric SAT model assays, illustrating the benefits of tailored surface area which is readily available for small-molecule anchoring. Very promising assay performance was shown for DNA hybridization assays with quantification limits down to 8 fmol.

Microfluidic preparation of monodisperse polymeric microspheres coated with silica nanoparticles

“…For example, layer-by-layer (LBL) assembly through sequential adsorption of polyelectrolytes (PELs) has been utilized to generate electrostatic attraction 31 – 33 . Surface modification based on the treatment of the amphiphilic coupling agent with preformed polymer particles are demonstrated to increase chemical affinity through van der Waals force, hydrogen bonding and dipole-dipole interaction 34 – 36 . Additionally, the synthetic procedures commonly require significant affinity between the inorganic silica particles and polymers to circumvent their inherent incompatibility.…”

Improving Continuous Flow Singlet Oxygen Photooxygenation Reactions with Functionalized Mesoporous Silica Nanoparticles

“…This reduction indicates that RB occupies the mesoporous channels of RB@MSNs, thus decreasing the total pore volume without complete clogging of the pores. The percentage of RB grafted to MSNs was estimated by thermogravimetric analysis (see Supporting Information, Figure S9b) after thorough washing sequences to remove any non‐grafted RB (Soxhlet). RB@MSNs samples were preheated at 350 °C, and the mass loss was measured between 400 °C and 800 °C.…”

Further insight into the mechanism of poly(styrene-co-methyl methacrylate) microsphere formation

“…MgSO 4 and KPS were used as received. Molar concentrations used for MgSO 4 and KPS (0.0051 M and 0.0005 M, respectively) were investigated prior to conducting mechanistic studies to achieve a desired particle size of 1 lm (results not reported here). The relative monomer composition and addition times in hours for each monomer are listed in Table 1.…”

“…INTRODUCTION Polystyrene latex microspheres (PSLs) are used in applications ranging from high-performance chromatography column packing materials to seeding materials for airflow velocity measurements in wind tunnels, as well as in drug-delivery and for other biomedical purposes. [1][2][3][4][5][6] NASA has particular interest in these meso-scaled materials due to their ubiquitous use, low production cost and complexity, and the large number of nearly geometrically identical particles that can be produced. The broad range of applications of polymeric microspheres has led to an extensive investigation of their synthesis, characterization, and properties for diverse uses.…”