Color-Tunable Microfluidic Synthesis of FITC/RITC-Functionalized POSS Hybrid Nanoparticles and in Vitro Biocompatibility Assessment

Abstract

Fluorescent nanomaterials are powerful tools for imaging and diagnostics, yet their performance depends critically on the control of particle morphology, stability, and emission characteristics. Polyhedral oligomeric silsesquioxane (POSS) offers a versatile platform for designing a stable and functional organosilica framework. In this study, we introduce a one-step microfluidic approach to synthesize fluorescent POSS nanoparticles labeled with FITC or RITC. A custom-designed PDMS microfluidic reactor enabled in situ emulsion formation, controlled droplet formation and UV-induced polymerization, producing highly uniform submicron spherical nanoparticles with strong and tunable fluorescence in one-step. Structural and chemical characterization (SEM, DLS, FTIR, and fluorescence microscopy) confirmed successful synthesis and fluorophore integration. Cytotoxicity and cellular responses were assessed in HepG2 cells via MTT viability, AO/PI staining, and wound-healing. Both FITC@POSS and RITC@POSS nanoparticles showed high biocompatibility and high cell viability (480%) across concentrations up to 200 mgmL 1, with minimal membrane damage, while higher doses modestly reduced cell migration. These results demonstrate that microfluidic processing provides a fast, scalable, and reproducible platform for creating biocompatible tunable fluorescent POSS nanoparticles with strong potential for multiplex bioimaging and theranostic applications.