β‐Cyclodextrin–Coated Paclitaxel‐Loaded Mesoporous Silica Nanocarriers: Mechanistic Insights Into Sustained Release, Enhanced Cellular Uptake, and Apoptosis in MCF‐7 Breast Cancer Cells

The present study aimed to develop and evaluate β-cyclodextrin (β-CD)-coated mesoporous silica nanoparticles (MSNs) for the controlled delivery of paclitaxel (PTX) to improve its aqueous solubility, stability, and anticancer efficacy. MSNs were synthesized by a sol-gel method using cetyltrimethylammonium bromide as a structure-directing agent and tetraethyl orthosilicate as a silica precursor, followed by PTX loading via solvent-evaporation and β-CD surface modification through physical adsorption. The synthesized nanocarriers were characterized by DLS, SEM, TEM, XRD, FTIR, BET, TGA, and DSC analyses to confirm morphology, particle size, crystallinity, porosity, and chemical interactions. β-CD-coated PTX-MSNs exhibited an average particle size of ∼137 nm with a narrow polydispersity index (0.189) and near-neutral zeta potential (-17.2 mV), indicating colloidal stability and successful surface functionalization. BET and DSC analyses confirmed drug encapsulation and amorphization within the silica matrix. In vitro drug-release studies revealed sustained release (≈69% over 72 h) governed by diffusion-controlled kinetics (Higuchi model, R² = 0.991). MTT assays on MCF-7 breast-cancer cells demonstrated markedly enhanced cytotoxicity of β-CD-PTX-MSN (IC₅₀ = 2.48 µg/mL, 48 h) compared with uncoated PTX-MSN and free PTX, attributed to improved cellular uptake (≈2.3-fold) and apoptosis induction. Furthermore, the formulation displayed negligible hemolysis (< 5%), confirming excellent hemocompatibility. Overall, β-CD-functionalized MSNs provide a promising nanoplatform for safe and sustained PTX delivery in breast-cancer chemotherapy.