A Facile Nanocarrier for Paclitaxel Delivery Based on Carboxymethyl Chitosan Encapsulated 6-Deoxy-6-Mercapto-β-Cyclodextrin Grafted Concave Cubic Gold

Paclitaxel is a first-line anticancer drug, but its low water solubility impedes bioavailability. The purpose of this study is to estalish a delivery strategy via carboxymethyl chitosan (CMCS)-encapsulated 6-deoxy-6-mercapto-β-cyclodextrins (dmβCDs)-modified concave cubic gold (CCGs) to achieve PTX release. CCGs were initially synthesized by the one-pot method and further modified by dmβCDs, the dmβCDs can effectively capture PTX molecules, followed by encapsulation with CMCS, and then prepare pH-responsive CMCS/dmβCDs/CCGs nanocarriers after lyophilization. Results indicated that desirable hexagonal CCGs with 50 ± 5 nm size can be obtained by adjusting H₂O₂ and HClO concentration. FT-IR, Raman and XRD spectra had confirmed dmβCDs successfully grafted to the surface of CCGs. Drug loading experiments demonstrated that the nanocarrier encapsulated PTX in amorphous powder or molecular form have a capacity of 55.05 µg/mL. Drug release experiments revealed PTX release from CMCS/dmβCDs/CCGs nanocarriers carrying a typical pH-responsive profile and indicating earlier release in an acidic environment than in a neutral or alkaline environment. The proposed method can be utilized to effectually achieve high-efficiency solubilization and targeted release inside tumor cells of PTX.