Study On Lactoferrin Modified Doxycycline Liposome Against Bacterial Biofilm

Bacterial biofilm is one of the main causes of human illness and infection,and most of the infections in hospitals are caused by biofilm.Biofilms are highly resistant to many antibiotics.By improving the administration of antibiotics,the dosage of antibiotics can be reduced,the effect of drugs can be improved,and a better solution can be provided for the treatment of bacterial biofilm infections.In this paper,positively charged lactoferrin was used to modify negatively charged liposomes to improve the stability of liposomes,increase their affinity for bacterial biofilms,and enhance the effect of doxycycline on bacterial biofilms.The specific research results are as follows:1.Doxycycline liposome(LD)was prepared by thin film dispersion method,and standard doxycycline curve was established by ultraviolet spectrophotometer.With particle size,surface potential and encapsulation rate as indexes,LD was optimized with the prescription of soybean lecithin 20 mg,doxycycline 8 mg and cholesterol 4 mg.And DSPE-PEG-2000 2mg,the preparation temperature is 50 ℃,the encapsulation efficiency is 55.77%2.Lactoferrin modified doxycycline liposome(LLD)was prepared by adsorption of positively charged lactoferrin onto negatively charged liposomes.The lipid particle size of doxycycline was 99 nm,and the Zeta potential was-49.47 m V.The hydrated particle size of lactoferrin modified doxycycline liposome was 99 nm,and the Zeta potential was 37.43 m V.3.The particle size changes of doxycycline liposomes and LLD within 48 h were detected by nano-laser particle size analyzer,and it was found that the introduction of doxycycline could stabilize the liposomes.Ultraviolet spectrophotometer was used to monitor the in vitro release of doxycycline in LD and LLD within 72 h.It was found that the release of doxycycline in LD was more than 50% in the first 48 h,and the release of drug was more than 75% at 72 h.At 72 h of LLD,only 13% of the drug was released.It was proved that lactoferrin was adsorbed on the surface of doxycycline liposome and its stability was enhanced.4.Two kinds of representative bacteria were selected;Bacterial biofilms were constructed by Pseudomonas aeruginosa and Staphyloccocus aureus in vitro.The effects of LLD on biofilm formation and biofilm formation were evaluated by crystal violet staining and MTT assay.The biofilm was observed by fluorescence microscopy and scanning electron microscopy.LLD was found to be more effective against bacterial biofilms than doxycycline or lactoferrin alone.In other words,LLD can not only effectively destroy the mature bacterial biofilm barrier,but also inhibit the formation of bacterial biofilm.In conclusion,the method of lactoferrin stabilizing liposomes is feasible.Lactoferrin modifying doxycycline liposomes can reduce antibiotic use to a certain extent and delay the formation of drug-resistant strains.This experimental scheme provides a new idea for the treatment of intractable infection caused by bacterial biofilm.