| Antibacterial composites are of great significance as new products on the basis of modern medicine and biological engineering,new materials,nano science and technology.Development and optimization of novel antibacterial materials are significant and hot in current researches,which can effectively avoid the defect of single component and show promising applications in clinical medical treatment,health care,food packaging,etc.Thus,the construction of organic/inorganic,inorganic/inorganic and bioactive/non-bioactive composite materials is a new approach to obtain a new generation of antibacterial nanocomposite materials with excellent properties.Zn O nanoparticles?NPs?have been widely used in the fields of antibacterial materials,UV shielding,chemical electronics and others due to the changes on surface structure and crystal structure.However,Zn O NPs possess unsatisfied antibacterial activity when the dosage is low.N-halamine compounds have attracted much attention attributing to their high-efficiency,broad-spectrum and reproducible antibacterial functions.In this work,it's proposed that N-halamine polymers were used as quick antibacterial agents and attached onto the surface of Zn O NPs,which realized the effective loading of organic antibacterial agent and filled in gaps of nano-antibacterial materials with excellent performance.Meanwhile,the interaction between two components was revealed.The structure and attachment form of the hybrids were optimized,and the proposed composites were used in different biomass polysaccharide structures to explore their applications in medical hemostasis dressings,food packaging films,textiles,etc.The bonding form between antibacterial materials and substrates was optimized to improve the antibacterial efficiency and stability in practical applications.In order to simplify the preparation procedure of Zn O matrix and reduce the organic solvent during the preparation process of composites,herein,zinc based composites were prepared by using a microwave approach.It not only optimized its biological antibacterial application,but also expanded its application to the field of biosensors.?1?It's proposed that Zn O NPs were used as the carriers and vinylbenzyl N-halamine based Zn O hybrids?Zn O-PVBDMH?nanoparticles were successfully prepared through atom transfer radical polymerization?ATRP?reaction using 2-bromoisobutyryl bromide and silane coupling agents.The stability test could be generalized as:On one hand,the introduction of zinc oxide nanoparticles significantly reduced the chlorine loss of the N-halamine compounds under ultraviolet light?UV?.After 24 h of UV irradiation,it can be restored up to 91%of initial loadings after rechlorination;On the other hand,the chlorinated nanoparticles were stable when kept in room temperature.According to antibacterial test,pure Zn O could kill49.53%of Staphylococcus aureus and 57.31%of Escherichia coli within 60 min.By contrast,the fabricated Zn O-PVBDMH-Cl NPs showed powerful bactericidal performance against both strains,and could inactivate 100.00%Gram-positive Staphylococcus aureus and100.00%Gram-negative Escherichia coli within 60 min.The antibacterial property of Zn O-PVBDMH-Cl NPs was much higher than that of Zn O.It can be seen from the cytotoxicity test that the prepared nanoparticles had good biocompatibility.The analysis of the degradation of methylene blue solution by Zn O-PVBDMH-Cl NPs showed that the prepared nanoparticles had excellent photocatalytic performance.?2?In the above-mentioned Zn O/vinylbenzyl N-halamine system,it is fully proved that the hybrid nanoparticles have stronger antibacterial efficiency.But,the preparation steps were complicated and there was the problem of copper ion residue.On the basis of preserving the structure of hydantoin,the siloxane N-halamine compound with stronger reactivity was selected and the surface of nano-Zn O was directly modified by PSPH via a one-step refluxing method.Compared with Zn O-PVBDMH-Cl NPs,the dosage of PSPH is lower with similar chlorine content,and the preparation process of Zn O-PSPH-Cl is simpler.In order to expand the application of nanomaterials,novel chitosan dressings?CS/Zn O-PSPH-Cl?impregnated with Zn O-PSPH-Cl hybrid nanoparticles were developed combining with freeze-drying and ultrasonic treatments.The prepared CS/Zn O-PSPH-Cl antibacterial dressing had good UV and storage stabilities.The prepared composite dressing after being stored for a month was sufficient to kill 99.93%of Staphylococcus aureus and 88.01%of Escherichia coli within 30min.The antibacterial dressing assembled much more platelets and red blood cells as compared with pure chitosan control.Moreover,the lower blooding clotting index value provided the evidence that these composites could control hemorrhaging and reduce the probability of wound infection.No potential skin irritation and toxicity were detected using in vitro cytocompatibility and skin stimulation tests.?3?Due to the presence of characteristic amino groups,chitosan can not only be used as a substrate,but also as a precursor of natural N-halamine compound.In order to expand the application of acyclic N-halamine compounds,combining with the characteristics of chitosan functional groups,Zn O-CS hybrids were prepared through a co-precipitation method.And then novel CNF/Zn O-CS films have been fabricated through the incorporation of Zn O-CS hybrids into CNF suspension.The stability and antibacterial performance were tested and the effect of CNF/Zn O-CS-Cl on the bacterial biofilm was explored.The chlorine content of the composite films could be restored to 75%of the initial loadings after 24 h of UV irradiation;Meanwhile,the active chlorine content in samples decreased from 0.35%to 0.30%during storage,showing good stability.The prepared antibacterial CNF/Zn O-CS-Cl films could kill99.92%of Staphylococcus aureus and 98.37%of Escherichia coli within 30 min of contact.The biofilm test showed that CNF/Zn O-CS-Cl had a slight inhibitory effect on the formation of bacterial biofilm compared with the control samples CNF and CNF/Zn O-CS,and cytotoxicity evaluations revealed the feasibility of the films for in vitro applications.?4?The introduction of Zn O/N-halamine compound nanoparticles has a positive effect on the antibacterial property of the composites,but the antibacterial efficiency of the composites prepared by the filling method is low.Compared with the blending method,preparing antibacterial composite materials with substrate carriers loaded with antibacterial agents are considered to be an ideal way.In order to expand the application of Zn O and N-halamine compounds,further improve the stability and antibacterial efficiency of the composites,multifunctional cotton fabrics were prepared with the coatings of Zn O,PSPH,and PHDTMS by the traditional dip-pad-cure technique.The stability test showed that after 25 washings,the chlorine content of Cotton/PHDTMS-Zn O-PSPH-Cl samples retained?0.23±0.02?%.After24 h of UV irradiation,90%of the initial chlorine content was restored.Compared with Cotton/PHDTMS-PSPH-Cl,Cotton/PHDTMS-Zn O-PSPH-Cl showed a faster sterilization speed,and could kill all inoculated Staphylococcus aureus and Escherichia coli within 10 min.Clearly,the advantage of high antibacterial efficiency of nano-based composites was not changed.The biofilm test results showed that the Cotton/PHDTMS-Zn O-PSPH-Cl could effectively inhibit the growth of bacterial biofilm.Furthermore,the antibacterial cotton fabric had excellent compatibility with mouse cells.?5?In the previous chapter,fibers were used as the antibacterial agent carrier and substrate to prepare composite materials with excellent antibacterial efficiency and stability.In order to further realize the covalent bonding among nanoparticles,antibacterial agents and cellulose nanofibrils,further reduce the consumption of organic solvents during the preparation of Zn O and the composites,we prepared zinc based nanoparticles?MWPPy-Zn O?by using an ultrafast?60 s?microwave approach.The prepared nanoparticles were blended with a water-soluble siloxane N-halamine antibacterial agent precursor PGHAPA,followed by adding to the cellulose nanofibrils suspension to produce antibacterial composite films CNF/MWPPy-Zn O-PGHAPA.The stability test showed that after 24 h of UV irradiation,about 80%of the lost chlorine could be regained after rechlorination.CNF/MWPPy-Zn O-PGHAPA-Cl provided 100.00%bacteria reduction against Staphylococcus aureus and Escherichia coli within 5 min of contact time.Also,the antibacterial composite films could effectively inhibit and remove biofilms produced by bacteria,revealing that the modified films posessed excellent antibacterial efficiency and stability.Biocompatibility test showed that CNF/MWPPy-Zn O-PGHAPA-Cl films were safe.In addition to showing antibacterial property and improving the UV light stability of N-halamines,the unique selection of nanostructure could broaden the application of the MWPPy-Zn O NPs to biosensor fields according to the structure and surface characteristics of the components.Experimental results revealed that the prepared GCE/MWPPy-Zn O sensor showed a linear range of 1.0×10-10-1.0×10-13 M and reliable determination of mismatched DNA molecules. |
PDF Full Text Request