Feasibility Study Of Graphene-based Accurate Photothermal Therapy Carrier For Anti-scarring In Glaucoma Surgery

Purpose:Glaucoma,the worldwide leading cause of irreversible blindness,will affect more than 111.8 million people in 2040.It is clear that the level of intraocular pressure(IOP)is related to the death of retinal ganglion cell(RGC).Until now,reducing IOP is the only proven therapy to delay the progression of optic neuropathy.Incisional surgery such as filtration surgery is required when the drug therapy cannot achieve satisfactory IOP reduction.Unfortunately,the excessive proliferation of fibroblast and remodeled collagen around the bleb could result in surgical failure as time grows.To prevent the fibrosis of bleb,antimetabolites are commonly used during filtration surgery,but large dose use of antimetabolite would inevitably increase the incidence of adverse effects Therefore,there is still a crucial challenge to develop a safer method to inhibit the proliferation of conjunctival fibroblast for the long-term.Photothermal therapy(PTT)is one of the emerging thermal therapies in recent years,which mainly relies on photothermal agents to absorb near infrared(NIR)light and convert into heat energy.The main purpose is to kill the surrounding cells and tissues.This work is to explore the anti-scarring effect of chemotherapy-photothermal therapy realized by graphene-based nanomaterials after glaucoma filtration,so as to provide a theoretical basis for its subsequent clinical application.Methods:Nano-silver-loaded reduced graphene oxide composite(r GO-Ag)was prepared by hydrothermal method,and then encapsulated with 5-Fu by polyvinyl alcohol hydrogel(PVA),and finally PVA@r GO-Ag/5-Fu was obtained.The antibacterial properties of PVA@r GO-Ag in Staphylococcus aureus and Escherichia coli were verified by dilution coating plate method and inhibition zone method.CCK-8 and live dead cell staining was used to verify the toxicity of PVA@r GO-Ag on RCF,HCECs,L929,HUVECs as well as the precise cell killing ability combined with 808 nm nearinfrared light.In the filtration surgery model,the anti-scarring effect of PVA@r GOAg/5-Fu was verified from the perspectives of filter bubble morphology,anterior chamber depth,intraocular pressure changes and histopathology.Results:Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy analysis and other characterization methods proved that r GO-Ag and PVA@r GO-Ag/5-Fu were successfully prepared.PVA@r GO-Ag has obvious antibacterial effect against Escherichia coli and Staphylococcus aureus.After 1,3,and 5 days of co-culture with PVA@r GO-Ag,the cell viability of each cell line was above 80%,and no dead cells were found;while after irradiation with 808 nm NIR,the cell viability of RCF decreased to 43.5 ± 0.08% as well as a large number of dead cells can be seen in the live-dead staining.In the filtration surgery model,the PVA@r GO-Ag/5-Fu group had a filter bleb survival time of 22.2 ± 2.5 days,and the intraocular pressure also remained at a lower level with a more stable change.Histopathological results showed that in the PVA@r GO-Ag/5-Fu group,there were obvious voids in the filtration area,the arrangement of connective tissues was looser,the deposition area of collagen fibers was smaller,and the number of α-SMA positive cells was significantly reduced.Conclusion:A multifunctional anti-scarring platform(PVA@r GO-Ag/5-Fu)integrated with the outstanding photothermal,antibacterial and drug delivery abilities is developed.PVA@r GO-Ag showed favorable biocompatibility as well as accurate regional photothermal killing ability on both conjunctival fibroblast and bacteria under 808 nm NIR irradiation.Furthermore,PVA@r GO-Ag/5-Fu improved bleb survival rates and resulted in the satisfying reduction of intraocular pressure by decreasing the fibrous reaction in vivo.In summary,PVA@r GO-Ag/5-Fu represents promising potential as an efficacious and safe anti-scarring agent for filtering surgery.