Study On Preparation Of Sodium Alginate/Chitosan/ZnO Composite Material And Their Application In Drug Sustained Release And Food Perservation

Sodium alginate?SA?,a natural polysaccharide,has been widely appied in medical field and food industry owing to various advantages,such as nontoxity,excellent biocompatibility,biodegradability,inexpensiveness,abundance,pH-sensitivity,and ease to form gels with multivalent cations.However,working as drug carrier and food preservative film,SA shows some drawbacks including poor mechanical properties and high swelling ratio,which limits its further application in food and pharmaceuticals.Nanoparticles serving as crosslinker are available method to improve mechanical properties of SA and broaden the scope of application.To verify its validity,ZnO nanoparticles?ZnO NPs?were fabricated by direct precipitation,then added into SA hydrogel beads to evaluate the effect on swelling and release performances,finally added into SA films to investigate the influence on mechanical properties and perservative performances.Zn?OH?₂ was firstly prepared by the zinc source?Zn?NO₃?₂·6H₂O?and precipitant?NaOH?with carboxymethyl chitosan?CMCS?acting as dispersant and stabilizer.The obtained Zn?OH?₂ was dehydrated and dried to form ZnO nanoparticles?CMCS-ZnO NPs?.CMCS-ZnO NPs were characterized by X-ray diffraction?XRD?,transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,Fourier transform infrared spectroscopy?FTIR?and UV-vis spectroscopy.CMCS-ZnO NPs were added into SA hydrogel beads to prepare SA/CMCS-ZnO hydrogel beads.The swelling and release performances of the hydrogel beads were charaterized by swelling and release assays both in vivro and in vivo.CMCS-ZnO NPs were introduced into SA films to evaluate the effect on mechanical properties,water vapor permeability,water solubility,antibacterial properties,and perservative performances.The main conclusions are as follows:?1?As-prepared CMCS-ZnO NPs appeared a nearly spherical and irregular morphology with an average diameter of 100 nm.As-prepared CMCS-ZnO NPs showed low cytotoxicity to MC3T3-E1 cells when the concentration was below 0.1 mmol/L,and exhibited distinctive antibacterial activity against S.aureus and E.coli.?2?SA/CMCS-ZnO hydrogel beads showed negligible cytotoxicity at test concentration.The addition of CMCS-ZnO NPs effectively decreased swelling ratio and improved release performances of SA hydrogel beads.SA/CMCS-ZnO hydrogel beads improved the stability of curcumin under UV irradiation,showed pH-sensitive release and higher bioavailability.?3?The addition of CMCS-ZnO NPs into SA films led to enhanced tensile strength,better water vapor resistance and decreased elongation at break.The addition of CMCS-ZnO films improved water vapor resistence,decreased transmittance in the UV region,improved antibacterial activity against S.aureus and E.coli and showed better perservative performances,which could promote the practical application of sodium alginate films in food perservation.