Well-defined drug-conjugated biodegradable nanoparticles by azide-alkyne click crosslinking in miniemulsion

A new type of biodegradable polymer-drug nanoconjugate was fabricated via the combination of oil-in-water miniemulsion and Huisgen azide-alkyne click chemistry. Diazide-functionalized paclitaxel (PTXL) were prepared through functional group transformation on the C-2′ and C-7 positions of PTXL and served as both drug carrier and crosslinker. Acetylene-functionalized polylactide (PLA) was used as the base polymer. Oil-in-water miniemulsion technique was used to create nanodroplets with diameters of round 50 nm, which were used as nanoreactors to control the size and morphology of the drug conjugates. Using sodium ascorbate/CuSO₄·5H₂O as catalysts, click reaction was performed within the nanodroplets between the azide functionalities of the PTXL-based crosslinker and the pendant acetylene groups of the functional PLA. High extent of reaction was confirmed by FTIR analysis and the resulting drug-conjugated nanoparticles were characterized by dynamic light scattering, transmission electron microscopy, and atomic force microscopy measurements. These NPs exhibited considerable degradation in proteinase K solution within 1 week.