Introduction

Fluorescent particles are prepared by incorporating selected fluorophores into monodisperse polystyrene particles through swelling process or copolymerizing styrene with various organic fluorescent dyes, which produce fluorophores labeled polystyrene particles with satisfactory properties. This series of fluorescent microspheres are obtained by encapsulating aggregation-induced emission (AIE) molecules in polystyrene. AIE molecules are embedded inside the microspheres, and owing to the characteristics of aggregation-induced emission, there is no fluorescence quenching effect during aggregation, which can significantly improve the fluorescence efficiency of AIE molecules. Meanwhile, after being encapsulated in polystyrene, AIE molecules are isolated from the influences of external environment, greatly improving their fluorescence stability and achieving durable as well as stable fluorescence effects. Functional groups or biological macromolecules (carboxyl, amino, hydroxyl, streptavidin, etc.) can be quantitatively modified on the surface of microsphere as linking groups for immunoanalysis, making AIE fluorescent polystyrene microspheres have a wide range of applications, including lateral chromatography, cell imaging, microfluidics and fluorescence enzyme-related immunosorbent assay. Fluorescent particles with single or multiple fluorophores are available in various sizes, emission spectra and combinations. Many are suitable for uses in flow cytometry, fluorescence microscopy, phagocytosis studies, and cell labeling[1-6].

Abvigen Inc. offers a wide range of AIE PS Fluorescent Particles, including Green AIE PS Fluorescent Particles, Yellow AIE PS Fluorescent Particles, Blue AIE PS Fluorescent Particles, Red AIE PS Fluorescent Particles and NIR-Ⅱ AIE PS Fluorescent Particles. The product size is adjustable in the range of 50 - 500 nm, and can be further flexibly adjusted according to customer requirements and use conditions to achieve customized supply.

Preparation Method

Miniemulsion polymerization[5]: Aggregation-induced emission (AIE) polymeric nanoparticles (PNPs) were efficiently synthesized by encapsulating a model AIE luminogen, tetraphenylethylene (TPE), within a polymeric matrix via miniemulsion polymerization.  The AIE PNPs with similar emission and particle properties were synthesized in a wide solid content range of 8 – 40 wt%.  The particle size and photoluminescence intensity of AIE PNPs could be flexibly tuned by synthetic parameters including the surfactant content and TPE content. Furthermore, the surface carboxyl- and amino-functionalization of AIE PNPs were conveniently achieved through copolymerization of styrene and functional monomers methacrylic acid and 2-aminoethyl methacrylate hydrochloride, respectively, in miniemulsions. The surface functionalization extent could be facilely tuned by the content of functional monomers. This miniemulsion polymerization based technique could be a feasible and efficient method to prepare AIE PNPs with versatile surface functionalization, tunable brightness, and controllable particle properties for the applications in biodetection, bioimaging, etc.

Combined swelling-diffusion technique[7]: A series of water-insoluble, biologically compatible dyes, meso-tetraphenylchlorin, meso tetraphenylporphyrin and chlorophyll-a, were successfully incorporated into beads composed of linear polystyrene (PS) via a tunable combined swelling-diffusion process. Dyed PS beads were prepared by the addition of a dye solution in tetrahydrofuran to an aqueous suspension of 10 lm PS beads in the presence of a poly((ethylene glycol)-b-(propylene glycol)-b-(ethylene glycol)) block copolymer surfactant. The presence of surfactant was found to be beneficial to prevent particle aggregation, especially at tetrahydrofuran contents above 30%. Dye loading was shown to be tunable by simple adjustments in dye composition.

Self-assembly of copolymers containing AIE moieties[8]: A cross-linkable aggregation induced emission (AIE) dye (named as R-E) with two vinyl end groups was facilely incorporated into polymer nanoparticles through reversible addition–fragmentation chain transfer polymerization. Thus obtained polymeric nanoparticles showed uniform size, high water dispersibility, strong red fluorescence and excellent biocompatibility, making them promising for cell imaging applications.

Co-nanoprecipitation[9]: Aggregation-induced emission (AIE)-active polymer prodrug nanoparticles were readily prepared by growing short, well-defined polymer chains from an AIE dye by nitroxide-mediated polymerization, followed by co-nanoprecipitation of the resulting conjugates with similarly constructed anticancer polymer prodrugs. The nanoparticles had sharp fluorescence signal offering excellent imaging ability in living cells and their intra cellular localization to be accurately monitored.

Emulsion polymerization[10]: A polymerizable AIE dye (named as PhE) with double bond end functional group as one of components was facilely incorporated into hydrophobic core of polymer nanoparticles. Thus obtained polymer nanoparticles (named as PhE-Pst NPs) emitted strong fluorescence and high water dispersibility owing to partial aggregation of PhE and surface covered with hydrophilic shell. More important, these FONs showed spherical morphology, uniform size (about 200 nm) and excellent biocompatibility, making them promising for bioimaging applications.

Application

Phagocytosis studies[3];

Cell imaging[8];

Tracking;

Calibration of flow cytometry;

Lateral chromatography;

Microfluidics;

Fluorescence enzyme-related immunosorbent assay;

Fluorescence microscopy

Advantages

Excellent application effect;

Aggregation induced luminescence characteristics, effectively prevent fluorescence quenching;

Good monodispersity, the microsphere particle size is highly uniform and evenly distributed;

Excellent fluorescence performance, Stokes shift is large, absolute quantum yield is high;

High density of surface functional groups, efficiently couple target proteins