Preparation And Antibacterial Application Of Novel Metal-Organic Frameworks Composite Films

The increasing bacterial resistance caused by traditional antibiotic therapy has become a major threat to human health.Therefore,there is an urgent need to develop viable alternative methods to achieve effective antimicrobial activity without triggering any bacterial resistance.The physical antibacterial stragtegy has attracted extensive attentions since it has no risk of triggering drug resistance of bacteria.Metal-organic frameworks(MOFs)have become a potential platform for physical antibacterial applications due to their diverse types,functionality and biocompatibility.However,most MOFs materials exist in the form of the powder or block.Assembling MOFs particles on desired surfaces can further expand their application in antibacterial surfaces,thus the MOFs films are able to provide platforms for the implementation of novel antimicrobial strategies.Considering the inherent limitations of MOFs synthesis conditions,it is still a challenge to construct MOFs films on substrates.Therefore,aiming at the limitation of conventional antibacterial therapies that mostly rely on the release of bactericidal agents and easily lead to the emergence of drug-resistant pathogens,different MOFs films were prepared through a facile and highly effective method to enhance the antibacterial effect.Three main works are as follows:1.A simple and facile strategy was developed to fabricate uniform MOFs layers on desired substrates under visible light with the assistance of dopamine(DA).With the illumination of visible light,DA and MOFs created a synergistic condition,leading to the formation of a uniform and stable MOFs film.Uniquely,UiO-66 played an important role in helping generate a suitable amount of reactive oxygen species(ROS)under visible light to promote DA polymerization,which in turn significantly facilitated the MOFs film formation.By introducing rose Bengal into the MOFs film,excellent photodynamic antibacterial activities against Gram-positive Staphylococcus aureus(S.aureus)and Gram-negative Escherichia coli(E.coli)were achieved.This MOFs film was capable of inactivating both S.aureus and E.coli with at least 99%success after a mere 5 min photodynamic therapy(PDT)process.Overall,this study provides a straightforward strategy in preparing MOFs thin films on desired substrates,which may help expand the antibacterial application of functionalized MOFs.2.The uniform and stable assembly of MOFs particles on the surface of surgical mask(SM)fibrous membrane(Fe@UiO-66@TA/SM)was achieved by using biologically friendly tannic acid(TA)as the main component.In this paper,it is proposed for the first time that the “photosensitization effect” of MOFs material can potentially improve the surface photodynamic antibacterial effect.In particular,in this layer-by-layer assembling process,interactions between the iron ion and TA can not only assist the rapid immobilization of MOFs particles on the surface,but the dye sensitization of Fe@TA can enhance the absorption of UiO-66 in the visible region,thus providing the possibility of photodynamic antimicrobial activity.Similar to the daily wearing process of masks,Fe@UiO-66@TA/SM had appropriate photothermal conversion properties under the illumination of simulated sunlight.In view of possible surface bacterial contamination during the wearing and placing of surgical masks,under simulated sunlight irradiation,Fe@UiO-66@TA/SM showed bactericidal effect against S.aureus and Pseudomonas aeruginosa(P.aeruginosa).This work provided a convenient,efficient and universal surface modification method to design and prepared medical antimicrobial materials,which has potential application in various field.3.In order to further deal with the bacterial adhesion and biofilm formation on the material surface,a MOFs film-based slippery liquid infused porous surface(SLIPS)was designed and prepared.This is the first “repellency” and “killing” slippery surface that relies entirely on physical properties to achieve the antibacterial performance,avoiding the dependence on biochemical antimicrobials.Firstly,a secondary growth method was used to grow the MOFs film(ZIF-L)in situ on the flat surface and medical catheters.The unique hydrophobic property and porous structure of ZIF-L was not only used as a textured substrate for constructing the slippery surface,but also had the mechanical sterilization ability.By infusing lubricating oil on the ZIF-L,this obtained slippery surface(ZIF-L-based SLIPS,ZLS)can transformed from an anti-adhesive surface to a structured bactericidal surface,which can provide the double protection for inhibiting the formation of biofilms on the surface.Specifically,the ZLS demonstrated a 99% resistance to the adhesion of P.aeruginasa after 24 h incubation and can transform from an antibiofouling surface to a bactericidal surface.Different from a single bactericidal surface,the ZLS possessed both anti-adhesion and structural bactericidal performances,in which the “bacteria repellency” and “bactericidal” effects were purely from the physical interaction.As an application example,ZLS on medical catheter can be utilized in the antibacterial modification for implant and intervention materials.Therefore,the MOFs film-based slippery surfaces provide a new perspective to design multifunctional and purely physical antibacterial surfaces in practical applications.