Bilayered nanosheets used for complex topography wound anti‑infection

There is a consensus that the prevention of wound infection should be achieved in the following ways:(1)closing the wound to protect it from extra infection;(2)an antibacterial agent that could kill endogenous bacteria.However,existing bulk two-dimensional antibacterial materials show inefficient adhesion to wounds with complex morphology and thus cause the prevention of wound closure.Reducing the thickness of bulk two-dimensional materials to less than 100 nanometres endows them with great flexibility,which could allow them to adhere to wounds with complex morphology by only physical adhesion.Herein,a broad-spectrum and efficient antimicrobial peptide(AMP)was introduced to biocompatible methacrylated gelatine(GelMA)with multiple modification sites,which served as an inner antibacterial layer.After being combined with a biodegradable and good mechanical poly-l-lactide(PLLA)outer layer through plasma-treatment-assisted spin coating,we finally constructed bilayered antibacterial nanosheets with a thickness of approximately 80 nm.These bilayered nanosheets possess good adhesion to surfaces with complex topography and thus achieve better wound closure than other bulk two-dimensional materials.Moreover,this AMP-grafted conjugation shows minimal cytotoxicity compared with Ag^+antibacterial agents,and the antibacterial rate of nanosheets is dependent on the graft rate of AMP.We suggest that this bilayered antibacterial nanosheet might be an advanced anti-infection dressing for wound treatment in clinical settings.

Generation of microfluidic gradients and their effects on cells behaviours

Introduction The concept of“gradients”has been widely demonstrated and applicated in biology.For example,concentration gradients and potential gradients in the body can regulate the homeostasis as well as the balance of physiological environment;oxygen gradients play a vital role in cellular gene expression and migration.

A sandwiched patch toward leakage-free and anti-postoperative tissue adhesion sealing of intestinal injuries

Ideal repair of intestinal injury requires a combination of leakage-free sealing and postoperative antiadhesion.However,neither conventional hand-sewn closures nor existing bioglues/patches can achieve such a combination.To this end,we develop a sandwiched patch composed of an inner adhesive and an outer antiadhesive layer that are topologically linked together through a reinforced interlayer.The inner adhesive layer tightly and instantly adheres to the wound sites via-NHS chemistry;the outer antiadhesive layer can inhibit cell and protein fouling based on the zwitterion structure;and the interlayer enhances the bulk resilience of the patch under excessive deformation.This complementary trilayer patch(TLP)possesses a unique combination of instant wet adhesion,high mechanical strength,and biological inertness.Both rat and pig models demonstrate that the sandwiched TLP can effectively seal intestinal injuries and inhibit undesired postoperative tissue adhesion.The study provides valuable insight into the design of multifunctional bioadhesives to enhance the treatment efficacy of intestinal injuries.