中国生物工程杂志

Objective: To obtain hepatitis B core virus-like particles containing RGD targeting peptide and provide a new carrier for drug targeting nanometer delivery system. Methods: RGD-modified recombinant plasmid of hepatitis B virus was transformed into E. coli BL21 (DE3), and the optimal expression conditions of recombinant protein were investigated by single factor analysis and orthogonal test. Under the optimum expression conditions, the bacteria were cultured, collected after ultrasonic crushing, centrifuged, purified by Gel filtration chromatography, ion exchange and sucrose density gradient centrifugation, and the morphology and stability of RGD-HBc VLPs were identified by transmission electron microscopy.The purified RGD-HBc VLPs loaded the photosensitizer ICG into the inner part of the particle and injected it intravenously into 4T1 tumor-bearing mice of breast cancer to explore the targeting of recombinant RGD-HBc VLPs as a nano-delivery system. Results: RGD-HBc VLPs was efficiently expressed in the form of soluble protein at 32℃ and IPTG at 0.5mmol/L for 4h.After centrifugation with sucrose density gradient, the purity reached above 95%.The purified RGD-HBc VLPs were observed under transmission electron microscopy in uniform shape and size, with a diameter of about 32nm. Near-infrared fluorescence in vivo imaging confirmed the targeting of RGD-HBc VLPs as a nano-carrier. Conclusion: After expression and purification, RGD-HBc VLPs has a high expression level and uniform appearance, and near-infrared fluorescence in vivo imaging has a good targeting property, which not only provides a fast, accurate and convenient method for the visual diagnosis of tumor, but also provides a new carrier for future targeted immunotherapy.