Nano/micro-materials For Skin Protection,Diagnosis And Treatment

Nano/micro-materials with nanometer and micron sizes have unique properties in surface effect,quantum size effect and volume effect,which make them widely used in optical,electrical,mechanical and magnetic fields.Skin is the organ with the largest exposed area of the human body.It is the first line of defense for the human body to resist external injury.It is closely related to the physical and psychological condition of the individual.Therefore,effective protection,diagnosis and treatment of skin diseases is of great significance for maintaining people’s physical and mental health.In this paper,we design and prepare three nano/micro-materials and apply them to the protection,detection and treatment of skin diseases based on the protection,detection and treatment system of skin diseases.Firstly,a kind of nanoparticles with ultraviolet(UV)shielding function was synthesized.The UV protection effect and scavenging effect of reactive oxygen species(ROS)on skin were investigated and compared with commercial sunscreen.In addition,two MNs for the diagnosis and treatment of skin diseases have been developed by combining two-dimensional nanomaterials and micromaterials with microneedles(MNs),and their detection and treatment in vitro and in vivo have been explored.The main contents contain three aspects as follows:(1)A multifunctional dendritic silicon dioxide nanoparticle(BS/BTO-DSM)with the properties of both inorganic and organic sunscreens was prepared and the ROS produced by sunscreens under UV could be removed in time.The nanoparticles were modified with the organic sunscreen(SM)by chemical bonding,which broadens the UV protection range of inorganic sunscreen and prevents the direct contact between organic sunscreen and skin epidermis,thus reducing the infiltration behavior of organic sunscreen into the skin.In addition,baicalin,a ROS scavenger,was coated on the nanoparticles,so that the ROS produced by the sunscreen under UV could be removed in time,effectively protecting the service life of the sunscreen and reducing the ROS damage to human skin.The nanoparticles designed in this work not only showed excellent UV resistance in vitro,but also proved to prevent UV-induced epidermal hyperplasia and keratinocytes apoptosis in vivo.(2)GO-GelMA MNs was prepared for simultaneous detection of three psoriasis-associated miRNAs in situ or in reaction fluid.GO-GelMA MNs used for extracting skin interstitial fluid(ISF)was prepared with methyl acrylamide gelatin(GelMA)and graphene oxide(GO)by optimizing the concentration of GelMA and GO and the time of UV crosslinking.GO-GelMA MNs showed good mechanical strength to penetrate the stratum corneum(SC).In addition,23.4 μL of ISF could be extracted in 30 min after skin insertion,providing a good basis for more accurate analysis of miRNAs in ISF.The design of GO-GelMA MNs makes full use of the two-dimensional nanomaterial GO,which has good adsorption properties on single strand DNA/RNA.The combination of GO and isothermal catalytic hairpin assembly signal amplification(CHA)enabled the enrichment and signal amplification detection of three low-abundance miRNAs in psoriasis ISF.The safety of the GO-GelMA MNs applied to mouse skin was also studied,and the results showed that the mouse skin could return to normal state half an hour after GO-GelMA MNs insertion.Finally,the microneedles were applied to the skin of normal mice and psoriatic mice,and the results showed that the microneedles could distinguish the two kinds of mice well.This work preliminarily enables simultaneous detection of three psoriasis-associated miRNAs in MNs in situ or in solution,providing significant impetus for monitoring ISF biomarkers.(3)An acid-responsive MNs(MnO2-Ag@GOx AMNs)that can be used to eliminate biofilms was prepared.A sea urchin-shaped MnO2-Ag particle was firstly synthesized,and glucose oxidase(GOx)was modified on the surface of the particle by electrostatic adsorption to obtain micron MnO2-Ag@GOx particles.GOx on the surface of MnO2-Ag@GOx can react with glucose in ISF to generate H2O2,which can react with MnO2-Ag nanoparticles to generate Ag+and ROS for sterilization.In vitro antibacterial and biofilm removal experiments proved that the particles have excellent antibacterial and biofilm removal performance.MnO2-Ag@GOx AMNs was prepared by combining MnO2-Ag@GOx,GelMA and NaHCO3,and MnO2Ag@GOx AMNs could release MnO2-Ag@GOx in response to the acidic environment of the biofilm.The results show that the MNs drug delivery system has a faster healing rate in the biofilm wounds of rats,indicating a good effect of biofilm removal.In this work,MNs is used as the delivery tool for epidermal drugs,which gives full play to the size advantage of MNs,and provides a comfortable and effective scheme for the treatment of stubborn biofilm diseases.