Self-assembly Targeted Carrier-free Nanodrug For Near-infrared Synergistic Cancer Theranostics

Cancer incidence and subsequent mortality are increasing rapidly worldwide in recent years.To address these issues,various multifunctional nanoparticles integrated with different diagnostic techniques and therapeutic methods have been fabricated,towards cancer diagnosis and treatment.Motivated by these considerations,herein,we report an alternative avenue to fabricate carrier-free,nanodrug formulation via self-assembly for targeting multimodal imaging-guided chemo-photo combination therapy.Initially,the hybrid nanoparticles were successfully fabricated and various physicochemical attributes were confirmed systematically using various characterization techniques.Gambogic Acid(GA)is a bioactive natural product with biological functionalities.GA and the near-infrared(NIR)dye indocyanine green(ICG)were anticipated to self-assemble into small molecule nanoparticles(GA-ICG nanoparticles,GI NPs)based on the molecular structures of precursor molecules.Then,the trace amount of FA-PEG-NH2 were used for surface functionalization to ensure the function of tumor targeting(GIF NPs).SEM images revealed that this self-assembly approach has resulted in highly uniform,spherical-shaped nanosized particles of GIF NPs with an average diameter of(100.05 ± 21.05)nm.The zeta potential of GIF NPs in the aqueous solution was(-24.45 ± 0.21)mV.FTIR,UV-vis and FL analyses have indicated that GA,ICG and FA-PEG-NH2 interacted with each other.The stability test showed that these GIF composites possessed excellent colloidal stability after 30 days of storage.In addition,GIF NPs exhibited significantly enhanced photostability and photothermal conversion compared to free ICG,which was consistent with FL analysis.The experimental results based on in vitro drug release implied that 808 nm laser irradiation could accelerate the release of GA from GIF NPs,which would benefit the drug release at the tumor sites.Secondly,to consider the superior properties of GIF NPs,we further explored their cellular uptake,cytotoxicity,and apoptosis towards MDA-MB-231 and 4T1 breast cancer cells.These results confirmed that the cellular uptake of GIF NPs was easier owing to their targeting efficiency.In vitro cytotoxicity experiment,remarkable cell killing efficacy of nanoparticles have been observed attributing to the improved solubility of GA.In addition,fluorescence staining of cancer cells using AO/EB staining kit simultaneously proved the excellent photothermal effect of GIF NPs under 808 nm laser.Moreover,the improved synergistic cell killing ability by combinatorial chemo-PTT-based GIF NPs as theranostic nanoplatform was clearly demonstrated.Finally,subcutaneous 4T1 tumor-bearing mice were selected as in vivo tumor model to evaluate the biodistribution,anti-tumor efficiency and biosafety of GIF NPs.The results of in vivo NIRF/PA dual-modal imaging showed that the blood circulation time of GIF NPs was significantly prolonged and NPs efficiently accumulated in the tumor at 12 h post-injection.To monitor the photothermal effect in vivo,the infrared thermal imaging and temperature changes of tumor were simultaneously recorded.As expected,the tumor temperature of mice treated with GIF NPs/laser reached 45.8 ?,which was sufficient to induce hyperthermia.After that,the results of immunofluorescence staining demonstrated that the GA as an HSP90 inhibitor resulted in the reduced thermoresistance of cancer cells and provided effective PTT at a mild temperature towards synergistic chemo-photothermal therapy.The combinational chemo-PTT using GIF NPs plus laser irradiation had almost reduced the tumor growth completely(the tumor growth inhibition rate was 100 %),showing remarkably higher inhibition efficiency of tumor growth compared with other control groups.Furthermore,the histological analysis of mice treated with GIF NPs/laser showed no significant off-target damage to normal tissues,attributing to their biocompatibility.Together,we developed a new carrier-free theranostic nanodrug via self-assembly for synergistic mild-temperature PTT and chemotherapy under the guidance of dual-modal imaging.