Preparation of specific immunoglobulin Y-conjugated chitosan nanoparticles and study on in vitro antibacterial activity and stability

HU Wenyue; TAN Kai; XU Qi; HAN Shuaijuan; CHEN Baojiang

doi:10.13557/j.cnki.issn1002-2813.2025.12.015

Abstract：This study aimed to prepare the conjugate(IgY-CN)of specific immunoglobulinY(IgY)against drug resistant Escherichia coli(E.coli)and chitosan nanoparticles(CN),and to evaluate its antibacterial activity and stability in vitro.The IgY-CN conjugate was prepared using the chemical coupling method.The minimum agglutination concentration(MAC)of specific IgY and the minimum inhibitory concentration(MIC)of CN and IgY-CN were determined by the microbroth dilution method,the thermal stability,pH value stability and antibacterial activity and stability of IgY-CN in synthetic gastrointestinal digestive fluids(containing digestive enzymes)were measured.Transmission electron microscopy was used to observe the effect of IgY-CN on the morphology of E.coli.The results showed that the specific IgY conjugated with CN formed an amide bond.The titer of specific IgY was 1∶12 000 and the MAC of specific IgY against E.coli was 128 mg/L,and the MIC of both CN and IgY-CN against E.coli was 2 g/L.The antibacterial curve indicated that both CN and IgY-CN exhibit strong antibacterial activity.After IgY-CN was heated in a water bath at different temperatures(25,30,and 37 ℃)for 5,15,and 30 min and treated under different pH value(3,7,and 9)for two hours,the MIC against E.coli remained unchanged.IgY-CN still exhibited strong antibacterial activity under simulated gastrointestinal conditions,demonstrating acid resistance and resistance to enzymatic digestion.IgY-CN disrupted the integrity of the E.coli cell membrane,causing uneven distribution of cytoplasm and leakage of cell contents,and severely damaging the microscopic structure of the bacteria.The study indicates that IgY-CN has positive antibacterial activity and antibacterial stability,and has the potential to be used as a new antibacterial agent to prevent and treat animal pathogen infection.