Construction Of A Nano-deliver System Based-poly (Mandelic Acid Ester) For Enhanced Tumor Therapy

Recently,polyesters have been shown to play an increasingly vital role in biopharmaceutical applications because of their excellent characteristics.The polyesters-mediated nanoparticles?NPs?drug delivery system excellent properties of biosafety and optimal drug loading capacity.However,they do not directly provide any extra therapeutic effect.Meanwhile,cancer chemotherapy can be enhanced by exploring novel polyesters,which can deliver therapeutic doses to the active sites and have some bioactivity,and this polyesters promotes its applications in drug deliever field.In this study,a bioactive poly?mandelic acid ester,noted as PMA?was rapidly synthesized by one-step polycondensation method under economical and convenient conditions from mandelic acid?MA?.For the first time,we investigated PMA which was a biotherapeutic nanocarrier for delivery of chemotherapy drugs,and we evaluated the in vitro and in vivo performance.This strategy broke the limit of traditional MA application in organic synthesis intermediates,antibacterial agents,fine cosmetics and other fields.The advantages of the novel PMA NPs platform are as follows?i?polymer is easy-to-synthesize and bioactive;?ii?NPs had small size and excellent stability;?iii?the nano-system had specifc passive tumor cell targeting ability;?iv?the system has good therapeutic effects in vitro and in vivo.The main conclusions of the study in vitro and in vivo are as follows:1.Synthesis of PMA.The PMA was synthesized by solution polycondensation.The ¹H NMR indicated that the resonance signals from the methylene protons of PMA??=6.21 ppm,d?were assigned to the formation of the ester linkage,while carboxyl and hydroxyl characteristic peaks of MA??=12.621 and?=5.02?basically disappeared.The FT-IR of products showed a new signal at 1754 cm^-1 related to the C=O bond stretching vibrations of the ester functional group,while-COOH group and-OH group of MA(3568 and 1722 cm^-1)basically disappeared.These resultes indicated that PMA was successful synthesized.The prepared polymer was confirmed to be PMA by ¹H NMR,FT-IR and TOF et,al.2.Preparation of PMA nanoparticles.The PMA NPs@PTX were successfully prepared by nano-precipitation,which includes following steps:firstly polymerization products was selected,then used DSPE-PEG3000,PTX and PMA?screened?was mixed as organic phase?DMSO,solvent?,finally prepared NPs with ultrapure water as the aqueous phase.The results of hydrated particle showed that the average size PMA NPs@PTX?2:1?was approximately67±5 nm.All PMA NPs@PTX samples were negatively charged?-25 mV?on the surface.TEM and SEM images of the samples confirmed the uniform spherical morphology.PMA NPs@PTX were incubated in PBS?pH 7.4?or 10%FBS up to a week,no precipitation or significant changes in diameter were observed implying excellent aqueous stability of PMA NPs@PTX.In vitro drug release was cumulated and reached 25%?pH 7.4?,40%?pH 6.8?and80%?pH 5.0?after 72 h.It should be noted that at pH 5.0,cumulative released of PTX was higher than that at pH 6.8 and pH 7.4.The above results proved that we have successfully prepared PMA nano-carrier,and the nano-carrier had good stability and tumor acid micro-environmental responsiveness.3.In vitro cell assay evaluation of PMA nanoparticles.The MTT cytotoxicity study of drug-free carrier demonstrated that it did not have significantly impair to 3T3?noncancerous line?cells and CT26?colorectal cancer line?cells.MTT test,live/dead,apoptosis,and invasion inhibition studies of PMA NPs@PTX showed that it significantly inhibited the proliferation of CT26 cells.In addition,we investigated in vitro cellular uptake and intracellular distribution of these formulations in CT26 cells by flow cytometry and laser confocal microscopy.It was found that CT26 cells had a significant time-dependent on the uptake of PMA nanocarrers.4.In vivo experimental evaluation of PMA nanocarrers.The in vivo biodistribution explore of the PMA NPs@DiR and PMA NPs@PTX/DiR nanoparticles showed that specific PEG-mediated PMA samples can successfully co-delivered PTX into the tumor tissue and could excellently passive targeting of the tumor site in vivo,which was highly beneficial for efficient drug delivery.More importantly,the PMA NPs@PTX had higher tumor inhibition which is possibly due to certain antitumor activity of the PMA nanocarriers and the PTX combination.These results clearly indicated that PMA had excellent bioactive properties which could considerably improve therapeutic antitumor efficacy.