Preparation, stimuli-response performance of HPC-PMAA/PpIX nanogels and their application in photodynamic therapy

In the present study, a novel nanogel of HPC-PMAA/PpIX with thermo- and pH sensitive performance and its application in cancer photodynamic therapy is reported. HPC-PMAA/PpIX nanogels were prepared by free radical polymerization method with HPC as template, hydroxypropyl cellulose (HPC), methyl acrylic acid (MAA), protoporphyrin IX (PpIX) and N,N'-methylene bisacrylamide (BIS) as raw materials. The as-prepared nanogels were characterized by Fourier transform infrared (FTIR), photoluminescence (PL) and UV-visible spectrophotometer (UV-vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM). PL and UV-vis spectra demonstrate that PpIX is incorporated into HPC-PMAA by covalent bonds, and its aggregation is prevented. Moreover, the as-prepared nanogels can be dispersed in water over 1 week, significant singlet oxygen can be produced under irradiation of laser. With tumor cell of HepG2 as model cell, the nanogels are biocompatible with cell viability of >85% even at high concentrations of the PpIX in vitro. In addition, the HPC-PMAA/PpIX nanogels show photo-dependent toxicity in the concentration range of 10 µg/mL of PpIX, suggesting that HPC-PMAA/PpIX nanogels have potential for the treatment of photodynamic therapy (PDT).