Dual-Functionalized Mesoporous Silica Nanoparticles for Celecoxib Delivery: Amine Grafting and Imidazolyl PEI Gatekeepers for Enhanced Loading and Controlled Release with Reduced Toxicity

The development of targeted drug delivery systems has been a pivotal area in nanomedicine, addressing challenges like low drug loading capacity, uncontrolled release, and systemic toxicity. This study aims to develop and evaluate dual-functionalized mesoporous silica nanoparticles (MSN) for targeted delivery of celecoxib, enhancing drug loading, achieving controlled release, and reducing systemic toxicity through amine grafting and imidazolyl polyethyleneimine (PEI) gatekeepers. MSN were synthesized using the sol–gel method and functionalized with (3-aminopropyl) triethoxysilane (APTES) to create amine-grafted MSN (MSN-NH₂). Celecoxib was loaded into MSN-NH₂, followed by conjugation of imidazole-functionalized PEI (IP) gatekeepers synthesized via carbodiimide coupling. Characterization was conducted using Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H-NMR). Drug loading capacity, entrapment efficiency, and in vitro drug release at pH 5.5 and 7.4 were evaluated. Cytotoxicity was assessed using the MTT assay on RAW 264.7 macrophages. The synthesized IP was confirmed by FTIR and ¹H-NMR. Amine-grafted MSN demonstrated a celecoxib loading capacity of 12.91 ± 2.02%, 2.1 times higher than non-functionalized MSN. In vitro release studies showed pH-responsive behavior with significantly higher celecoxib release from MSN-NH₂-celecoxib-IP at pH 5.5 compared to pH 7.4, achieving a 33% increase in release rate within 2 h. Cytotoxicity tests indicated significantly higher cell viability for IP-treated cells compared to PEI-treated cells, confirming reduced toxicity. The dual-functionalization of MSN with amine grafting and imidazolyl PEI gatekeepers enhances celecoxib loading and provides controlled pH-responsive drug release while reducing systemic toxicity. These findings highlight the potential of this advanced drug delivery system for targeted anti-inflammatory and anticancer therapies.