Construction Of Supramolecular Nanosystem Based On Carbohydrate Functionalized Pillar[5] Arene And Its Application In Drug Monitoring And Targeted Delivery

In the treatment of cancer,the chemotherapy method has low anti-cancer efficiency and side effects.However,the construction and application of the nano drug delivery system provides a new way to solve above problem.Using the difference in tumor microenvironment,constructing multifunctional nano drug delivery system with target and stimulating responses has become a research focus in the field of biomedicine.In supramolecular chemistry,the construction of nano drug delivery systems by means of the host-guest chemistry of macrocyclic molecules has attracted more and more attention.Using the excellent properties of pillar[n]arene to construct supramolecular nano drug delivery systems has become a powerful tool.Based on this,this paper introduces the near-infrared probe（DCM-NH₂）with dicyanomethylene-4H-pyran structure into the construction of supramolecular nano drug delivery system,and functionalized aromatic hydrocarbon（Man P5）with mannose.The amphiphilic molecule was formed by the chemistry of host and guest,and the vesicles were self-assembled by the hydrophobic interaction in water.After loading the drug of gemcitabine,a multifunctional supramolecular nano drug carrier with target transportation,controlled release and fluorescent monitor was formed.The construction of multi-functional nanomaterial with targeted delivery,stimulatory response and fluorescence localization by pillar[5]arenes is essential for solving problems such as low anti-cancer efficiency in cancer chemotherapy,high side effects on normal cells,and inability to monitor the release process of drugs in real time.Based on this,this paper introduces the near-infrared probe（DCM-NH₂）with dicyanomethylene-4H-pyran structure into the construction of supramolecular nanoparticle drug delivery system,and constructs a supramolecular nanoparticle drug delivery system with targeted transport,controlled release and fluorescence tracer by using mannose functionalized pillar[5]arenes（Man P5）.The main research contents of this paper include:（1）Preparation and characterization of nanoparticle drug delivery system:mannose-modified pillar[5]arene and DCM-NH₂ modified target guest molecule were complexed by host-guest interaction to form nanostructure.The nuclear magnetic data,UV absorption spectra and the Job curves of the host and guest at different concentration ratios verified that the carrier had a host-guest effect.The pictures of scanning electron microscopy and transmission electron microscopy showed that the nanocarrier had a vesicle structure with a particle size between 100 nm and 200 nm.The particle size distribution showed that the vesicles had a wide particle size distribution and the average particle size was 220 nm.And most of them were concentrated in below 200 nm.The Zeta potential at this time was33.5 m V.All of the results show that the nanovesicles have good size and fine stability.After loading gemcitabine（GEM）,the structure of the nanovesicles on the SEM images became irregular and the particle size increased.The average particle size of the nanomaterial was299 nm and the Zeta potential was-13 m V measured by laser particle size distribution analyzer.These results suggest that the vesicle loaded the drug successfully.（2）GSH stimulation responsiveness study:The vitro simulated release experiment was carried out,then the drug loading rate of the nanoparticle drug-loading system measured was60%.As the GSH concentration increased in the system,the drug release rate increased continuously to 78%after 24 hours in 2 m M GSH.When the concentration of GSH improved to 5 m M,the drug release rate reached more than 90%.In addition,the UV absorption and fluorescence emission recovered from 450 nm and 560 nm to 490 nm and650 nm respectively after adding 2 m M GSH to the guest molecule alone,which was consistent with the wavelength of near-infrared probe,further illustrating the vesicles are GSH stimulus-responsive.（3）Targeting study:MCF-7 cells pretreated with or without mannose were both co-cultured with vesicles,and then the near-infrared fluorescence intensity in the cells was observed by laser confocal.As a result,the fluorescence of the MCF-7 cells pretreated with mannose was stronger,instructing the targeting effects of the vesicles.It also proved that vesicles are responsive to GSH stimulation.The results are consistent with those obtained by flow cytometry analysis.（4）Cell uptake and cytotoxicity studies:the vesicles loaded the simulated drug sodium fluorescein and co-cultured with MCF-7 cells.As the culture time increasing,the near-infrared fluorescence and the green fluorescence of sodium fluorescein effectively overlapped.It showed that cells can effectively ingest vesicles and also the nanomaterial can realize real-time monitoring of drugs.In addition,cytotoxicity experiments were performed by MTT assays.It showed that the materials are essentially non-toxic to normal cells.After the vesicles were co-cultured with 293T and MCF-7 cells respectively,the nano drug-loading system had weaker toxic side effects on normal cells and stronger killing ability against cancer cells than pure drugs.In summary,this paper constructs a novel multifunctional supramolecular nano drug delivery system with sugar targeting,GSH stimulating responsiveness and real-time monitoring effect by virtue of the host-guest interaction of pillar[5]arenes and the activatable fluorescence localization of near infrared probes.We explored a new supramolecular drug-loading system with fluorescent tracer function by using a near infrared probe.It is hoped that this research work can provide a new idea for the application of pillar[n]arenes in nanoparticle drug delivery system.