Construction Of Double-layer Structure Polymer Films Controlled Release Antibody On Fracture Stent Surface

Open fractures are diseases of trauma orthopedics.With the popularity of modern transport and people's pace of life accelerated,the number of patients with open fractures increased year by year and the treatment is of difficulties.It must be implanted through the surgical fixation stent for adjuvant therapy.Antibiotic administration is a key step for treating open fracture especially for tainted bone caused by contamination and implants.However,traditional oral and injectable antibiotics are prone to irreversible damage to vital organs of the human body.Long-term uninterrupted antibiotic administration also produces resistant superbugs,which poses a serious threat to human health and even life.It is an effective strategy to solve the above problems by locally delivering antibiotics on the surface of the implant.Therefore,it is important to prepare a fractured fixation implant for long-acting controlled release antibiotics.Via electrospraying technology,with high drug-loaded and excellent control release ability,the composite structure of polymer film and porous fiber was developed to prepare the internal implant of loaded antibiotics.The main content is sumMarized as the following two parts:1.Preparation of PVA-B Microgel Film via electrosprayPolyvinyl alcohol-borax(PVA-B)microgels were prepared in aqueous solution using borax as crosslinking agent.PVA-B microgel film was prepared via electrospraying PVA-B.The results show that when the concentration of PVA and borax is 25 mg.m L-1 and 3.0 mM,respectively,the microgels with uniform particle size of 712.4 nm are obtained.The weight of PVA-B microgel was linearly correlated with the deposition time,and the deposition rate was 0.187 mg.cm-2.h-1.After electraspray for 1 h,a microgel film with a thickness of 1.35 ?m was obtained.The microgel films were characterized by Fourier transform infrared(FTIR)and thermogravimetric analysis(TGA).The mechanical properties of microgel films were studied by stress-strain curve.The drug loading capacity of PVA-B microgel was studied by using quercetin as the drug model.The results show that PVA-B microgel film has high drug loading ability and has potential application value in drug delivery field.2.Controlled release of vancomycin hydrochloride from a compound structure of polymeric films and porous fibres on implantsVancomycin hydrochloride(VH)was added to PVA-B microgel solution,and VH@PVA-B film was prepared by electrostatic spraying technique.VH@PVA-B membrane was soaked in normal saline and VH fully released within 5 min.It could effectively slow the release of VH by electrospinning polyvinyl butyral(PVB)fiber mats on VH@PVA-B films.When the weight of PVB fiber mats is 1.036 mg.cm-2,the release of VH can sustain 4 days.To further slow down the rate of release of VH,PVB fiber mats were treated by ethanol vapor.With the prolonged treated time,the contact angle of the PVB fiber mats decreases and the PVB fiber mats gradually changes into a porous membrance.The hole amont and size of PVB fiber mats both decrease.When the PVB fiber mat(0.842 mg.cm-2)was treated with ethanol for 12 min,the release time of VH could sustain 35 days(to meet the clinical requirement).The release kinetics were fitted by Weibull model and correlation efficient R2 is up to 0.982.In addition,the results showed that it was effective for inhibiting Staphylococcus aureus by 0.5,1 and 2 d release in normal saline for the VH@PVA-B/PVB membrane treated with ethanol for 12 min.The composite structure and drug release model are expected to be used in the field of implanted implant coatings for topical controlled release therapy.