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Bacterial adhesion infection caused by medical materials in clinical application has become a serious threat, and it urgently needs new strategies to deal with these clinical challenges. The purpose of this study is to explore the effectiveness of surface-decorated aryl (β-amino) ethyl ketones (AAEK), a promising sorting enzyme A (SrtA) inhibitor of Staphylococcus aureus , to improve the anti-adhesion ability of biomaterials. AAEK was covalently grafted onto cellulose films (CF) via copper-catalyzed azide-alkyne 1, 3-dipolar cycloaddition click reaction. The data of contact angle measurements, ATR-FTIR and XPS proved the successful covalent attachment of AAEK-CF, and the antimicrobial efficacy of AAEK coating was assessed by CFUs, crystal violet staining, scanning electron microscopy and Living/Dead bacteria staining assay. The results illustrated that AAEK-CF exhibited excellent anti-adhesion ability to Staphylococcus aureus , and significantly reduced the number of bacteria adhering to the film. More importantly, AAEK-CF could hinder the formation of bacterial biofilm. Furthermore, AAEK-CF indicated no cytotoxicity to mammalian cells, and the cells could grow normally on the modified surface. Hence, our present work demonstrated that the grafting of the SrtA inhibitor-AAEK onto cellulose films enabled to combat bacterial biofilm formation in biomedical applications. • AAEK attached on cellulose film as the novel anti-adhesion surface. • AAEK-functionalized cellulose film performed good anti-adhesion properties. • The modified film indicated no cytotoxicity to mammalian cells. [ABSTRACT FROM AUTHOR]

Highlights • LED 209 conjugated CS as the novel selective antimicrobial and anti-adhesion agent. • The conjugate exhibited higher selective antimicrobial on MDR- E. coli than CS. • The conjugate could reduce MDR- E. coli adhesion and prevent its biofilm formation. • The conjugate offered a potent antimicrobial for combating GNB infections. Graphical abstract Abstract The rapid emergence of antibiotic-resistant Gram-negative bacteria (GNB) is becoming a global healthcare concern, and it urgently needs novel strategies to match the clinical challenge. In this work, we conjugated chitosan (CS) with LED 209, a highly selective inhibitor of QseC of GNB, to create the novel selective antimicrobial agent CS/LED. The data of FT-IR, NMR and elemental analysis for CS/LED conjugates proved the successful conjugation of CS with LED 209. Interestingly, the fluorescence signal detected in MDR- E. coli of CS/LED-FITC was about 2 times than that of CS-FITC at 3 h. The results shown that compared with CS, CS/LED exhibited higher selective antimicrobial on MDR- E. coli. Moreover, CS/LED exhibited the lower selectivity and cytotoxicity to mammalian cell than CS. Additionally, an unexpected enhancement of anti-adhesion activity against MDR- E. coli was determined by cellulose membrane coating CS/LED. The results demonstrated that CS/LED could reduce the adhesion of bacteria to the cellulose membrane by about 67.8%, while CS only reduced by about 45.3%. The dressings coated with CS/LED possessed the stronger ability to prevent microbial adhesion compared to the CS-coated dressing. Our present work firstly demonstrated that CS/LED had a highly selective activity and anti-adhesion activity against MDR- E. coli , which offered a potent and selective antimicrobial for combating multidrug-resistant GNB infections. [ABSTRACT FROM AUTHOR]

• LED209 attached on cellulose membrane as the novel anti-adhesion surface. • LED209-functionalized cellulose membrane performed good anti-adhesion properties. • The modified membrane repressed the expression of bacterial virulence genes. • The modified membrane indicated no cytotoxicity to mammalian cells. Bacterial adhesion infection caused by medical materials in clinical application has become a serious threat, and it urgently needs new strategies to deal with these clinical challenges. In this work, LED209, a highly selective histidine sensor kinase inhibitor of Gram-negative bacteria, was covalently attached on cellulose membrane (CM) via click reaction. The data of contact angle measurements, ATR-FTIR and X-ray photoelectron spectroscopy confirmed the successful synthesis of LED-CM. In addition, the results of antibacterial activity of the membranes shown that LED-CM exhibited excellent anti-adhesion ability to Enterohemorrhagic Escherichia coli (EHEC), and significantly reduced the formation of bacterial biofilm. Importantly, LED-CM was able to repress the expression of virulence genes in EHEC. Furthermore, LED209-functionalized cellulose membrane indicated no cytotoxicity to mammalian cells. Hence, our present work demonstrated that CM modified with LED209 possessed markedly anti-adhesion activity against EHEC, which offered a potent antimicrobial material for combating bacterial infections. [ABSTRACT FROM AUTHOR]