Preparation and performance of pH-responsive nanocarriers for mucus penetration / 国际生物医学工程杂志

ABSTRACT

Objective To prepare pH-responsive osmotic nanocarriers (pMPPs),observe their distribution in the genital tract mucosa in mice,and evaluate their radiosensitizing effects in tumor cells.Methods Amphiphilic polymers containing pH-sensitive hydrazone bonds were synthesized and pMPPs were prepared by ultrasonic emulsification.At the same time,the hydrophobic polymer polylactic acid-glycolic acid copolymer (PLGA) and the amphiphilic polymer PLGA-polyethylene glycol without hydrazine bond were selected,and the mucoadhesive nanoparticles(MPs) and mucus-penetrating particles (MPPs) were prepared in the same way.Fluorescence microscopy was used to observe the distribution of three kinds of nanocarriers labeled with fluorescent dye Cy5.5 in the genital tract mucosa.The toxicity of nanocarriers to human cervical cancer cell line HeLa was tested by thiazolyl blue assay.The amphiphilic polymer containing pH-sensitive hydrazone bond was combined with oil-soluble gold nanoparticles to form a multi-encapsulated nanocarrier,and its radiotherapy sensitization effect in HeLa cells was evaluated by thiazole blue assay.Results The pMPPs were successfully prepared with relatively uniform particle size and good dispersion.Fluorescence microscopy showed that pMPPs not only had good mucus permeability,but also could improve the endocytosis efficiency of the nanocarriers in reproductive tract mucosa.The results of thiazolyl blue test showed that when the concentration of the carrier reached to 0.80 mg/ml,the survival rate of HeLa cells in the pMPPs group was higher than 90％ which was higher than that in the MPs and the MPPs groups,indicating that pMPPs had good biosafety.The HeLa cell survival rate of the CMNa group (0.80 mg/ml) was higher than that of the multi-package nanocarrier group under different doses of X-ray irradiation (4 Gy82.90％ vs.61.79％;8 Gy64.75 ％ vs.42.36％).This result indicated that compared with the CMNa,a commonly used clinical radiotherapy sensitizer,the multi-encapsulated nanocarriers can more effectively enhance the sensitivity of tumor cells to radiation therapy,thereby improving the lethality of radiation therapy on tumor cells.Conclusion This study solved the conflict between mucus permeation and endocytosis design of nanocarriers in mucosal tissue application,and provided new insight for the treatment of mucosal tissue diseases.