Co-assembly Of Peptide And Drug To Construct A Redox-responsive Nanocarrier

Peptides have attracted significant interest in recent years as part of a promising platform for fabricating drug carriers due to their low cytotoxicity,favorable biodegradability,easily introduced functional groups and self-assembled property.Therefore,a tumor-responsive,peptide-based drug carrier was developed by co-assembly of a pure peptide with a hydrophobic drug,curcumin(CCM)in this study.A disulfide bond,which is cleavable by glutathione(GSH),was included by design in this redox-responsive peptide(RRP),considering the GSH overexpression in tumor microenvironments.CCM@RRP had specific components,safe and green preparation process and importantly it had an obvious effect on antitumor.The main contents are as follows:(1)Preparation and characterization of drug delivery system: a pure peptide with disulfide bonds was designed as a drug carrier and its sequence was Ac-ATKTAC(S-S)CATKTA-Ac.By the way to adjust the additional mass of CCM and assembly time,proper conditions to prepared CCM@RRP was determined as follows: 0.5 mg/mL RRP and 0.3 mg/mL CCM mixed in PB(pH 5.5)and self-assembled under 16 ? for 1 h,shading and without any disturbance.Then,the solution containing CCM@RRP nanoparticles was obtained by centrifugating in 6000 rpm for 3 min under room temperature.The size of these nanoparticles was about 250 nm and the drug entrapment efficiency was 63.44%.CCM@RRP nanoparticle has a certain stability.Lyophilization and redissolved process had no obvious influence on its diameter distribution.And it could maintain its original structure in 24 h under solution state.Furthermore,CCM@RRP could be stable in the environment containing 20% serum,which could meet the requirements of the long circulation.In an environment containing 8 mM GSH,RRP ruptured in response to GSH,and nanospheres crashed,which indicated that CCM@RRP had obvious GSH redox responsiveness.(2)Evaluation to the responsive-released effect of drug system: in vitro release experiment,CCM@RRP could be stable under normal pH value of human condition.With the adding of GSH concentration,the rate of CCM@RRP to release CCM gradually increased.When the concentration of GSH in the solution reached 8 mM,the drug release ratio in 4 h was above 90%.Through cell uptake experiments and cytotoxicity tests,the results proved that CCM@RRP could be easily absorbed by cells,which effectively improved the water solubility and bioavailability of CCM.Also,the experimental results showed that RRP had low cytotoxicity and high biocompatibility.When the concentration of CCM was 50 ?g/mL in CCM@RRP,the lethality rate of HeLa cells was 88.03%,which was 4.26 times to that of free CCM,and the lethality rate for MAD-MB-231 cells was 98.90%,which was 1.3 times to that of free CCM.In vivo,the inhibitory rate of CCM@RRP on MAD-MB-231 breast cancer was 61.88% and the inhibition rate of HeLa cervical cancer was 69.12%.All of them showed CCM@RRP had a significant tumor inhibition effect.Histopathological analysis showed that CCM@RRP had smaller toxic and side effects on healthy cells under an effective concentration.TUNEL immunohistochemical analysis showed that CCM@RRP could cause tumor cells to be apoptosis.