Polydopamine coated hollow mesoporous silica nanoparticles as pH-sensitive nanocarriers for overcoming multidrug resistance

A nanocarrier system of methoxypolyethylene glycol amine (mPEG-NH2) functionalized polydopamine (PDA) coated hollow mesoporous silica nanoparticles (HMSNs-PDA-PEG) was developed with pH-responsive, which combined doxorubicin hydrochloride (DOX) and quercetin (QUR) to reverse multidrug resistance (MDR) and improved anticancer effects on taxol (TAX) and DOX double resistant human colorectal cancer cell line HCT-8 (HCT-8/TAX cells). Well-dispersed nanoparticles (HMSNs-PDA-PEG) were prepared with a dimension of around 170 nm. The surface morphology and chemical properties of HMSNs-PDA-PEG were also successfully characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, Fourier transform infrared spectroscopy (FT-IR) and dynamic light scattering (DLS). Drug release experiments results indicated that DOX and QUR (QD) loaded nanoparticles (HMSNs-PDA-PEG@QD) had similar release kinetic profiles of each drug, which all exhibited highly sensitive to pH value due to the surface PDA coating. Additionally, the HCT-8 cells or HCT-8/TAX cells were employed to assess the cellular uptake and cytotoxicity of various drug-free or drug-loaded HMSNs samples. Meanwhile, a series of biological evaluations demonstrated that the HMSNs-PDA-PEG@QD exhibited remarkable ability to overcome MDR compared with free DOX and HMSNs-PDA-PEG@DOX. Taken together, these results revealed that HMSNs-PDA-PEG@QD was suitable as a prospective and efficient drug delivery nanosystem for overcoming multidrug resistance.