Preparation Of Dialdehyde Cellulose And Evaluation Of Its Antibacterial Properties

Cellulose,which is the most abundant renewable resource in the world,possesses several properties such as large specific surface area,excellent biodegradability and biocompatibility.It has gained much attention for using as tissue engineering,wound dressing,packing material,and electronic materials.In this paper,dialdehyde cellulose with different aldehyde content was prepared and its antimicrobial properties were determined.Firstly,dialdehyde cellulose can be synthesized by using periodate sodium which can selectively oxidize the hydroxyl group into aldehyde group on the C2-C3 position of glucose unit.We optimized the reacting conditions by controlling reacting time and the concentration of sodium periodate,and obtained dialdehyde cellophane(DACP)and dialdehyde nanocrystalline cellulose(DANCC)with different content of aldehyde groups.The aldehyde contents of DACP increased with the increasing oxidation degree,and the highest aldehyde contents of DACP was 8.8 mmol/g.DACP showed better optical properties compared with cellophane,and the transmittance was above 90%.Secondly,we studied the effects of aldehyde content on the surface structure,mechanical properties,optical properties,thermal stability,crystallinity,and antimicrobial properties of DACP.The surface roughness and contact angle increased with increase aldehyde contents,and the mechanical properties and thermal stability decreased as increased aldehyde contents.The optical properties of DACP were improved through oxidization.DACP exhibited excellent antibacterial activity against four kind of Gram-positive bacteria include Staphylococcus aureus(S.a),Methicillin-resistant Staphylococcus aureus(MRSA),Staphylococcus epidermidis(S.e),and Streptococcus pneumoniae(S.p).DACP showed excellent antibacterial property towards 1?10~5-1?10~6CFU/mL of bacteria,and the effect could maintain at least 24 h.Finally,we studied the effects of aldehyde content on the morphology,Zeta potential,and antimicrobial properties of DANCC.The size and Zeta potential of DANCC decreased with the increasing aldehyde contents.DANCC showed strong antibacterial activity against S.a and MRSA.DANCC showed excellent antibacterial property towards1×10~7-1×10~8 CFU/mL of bacteria,and the effect could maintain at least 24 h.