pH-responsive Nanomedicine Delivery Platform Based on Silicon Nanoparticles for Imaging and Photodynamic Therapy of Tumor Cells.

Abstract

Introduction: Fluorescent silicon nanoparticles (Si NPs) are attractive bioimaging probes, but their emission is mainly confined to the blue-green region, resulting in poor penetration into tissues and strong autofluorescence interference. Moreover, most systems based on Si NPs are designed for single-function imaging or sensing, which limits their use in the delivery and treatment of tumortargeted drugs.

Methods: Long wavelength fluorescent Si NPs with high physicochemical stability have been synthesised and incorporated into mesoporous silica nanoparticles (MSNs) for drug delivery. Chlorine e6 (Ce6) has been encapsulated as a photosensitizer. The resulting nanocomposites were coated with polydopamine (PDA) and functionalised with folic acid (FA) to realize active tumor-targeting capability.

Results: The synthesized Si NPs showed stable long-wavelength fluorescence suitable for biological imaging. The FA-Si NPs-MSNs-PDA@Ce6 nanocomposite benefited from the FA-mediated targeting, increased permeability and retention effects and demonstrated increased tumor accumulation and cellular uptake. This strategy achieved tumor-specific fluorescence imaging, permitted real-time tracking of tumor cells, and boosted intracellular Ce6 delivery, thereby significantly elevating the photodynamic therapy (PDT) efficiency Discussion: This study presents a multifunctional nanoplatform that combines long-wave fluorescence imaging and pH-sensitive photodynamic therapy, thereby overcoming the significant limitations of traditional silicon nanoparticle-based systems. Targeted delivery and controlled release of drugs improve the accuracy of therapy and the effectiveness of imaging, and offer a promising strategy for tumor theranostics.

Conclusion: A multifunctional drug delivery nanoplatform based on Si NPs integrating targeted fluorescence imaging and photodynamic therapy has been successfully developed. This system holds great promise for tumor-targeted drug delivery and integrated theranostic applications.