Fabrication of UV responsive micelles-containing multilayers and their influence on cell adhesion

A versatile pH-responsive peptide based dynamic biointerface for tracking bacteria killing and infection resistance

Herein we reported a versatile dynamic biointerface based on pH-responsive peptide self-assembly and disassembly to capture the bacteria to avoid bacteria further infected tissue around that can release peptides from the surface in a slightly acidic environment to kill the bacteria with the specificity. The exposed biointerface still presented infection resistance.

UV-Responsive Multilayers with Multiple Functions for Biofilm Destruction and Tissue Regeneration

The increasing demands of surgical implantation highlight the significance of anti-infection of medical devices, especially antibiofilm contamination on the surface of implants. The biofilms developed by colonized microbes will largely hinder the adhesion of host cells, leading to failure in long-term applications. In this work, UV-responsive multilayers were fabricated by stepwise assembly of poly(pyrenemethyl acrylate- co-acrylic acid) (P(PA- co-AA)) micelles and chitosan on different types of substrates. Under UV irradiation, the cleavage of pyrene ester bonds in the P(PA- co-AA) molecules resulted in the increase of roughness and hydrophilicity of the multilayers. During this process, reactive oxygen species were generated in situ within 10 s, which destroyed the biofilms of Staphylococcus aureus, leading to the degradation of the bacterial matrix. The antibacterial rate was above 99.999%. The UV-irradiated multilayers allowed the attachment and proliferation of fibroblasts, endothelial cells, and smooth muscle cells, benefiting tissue integration of the implants. When poly(dimethylsiloxane) slices with the multilayers were implanted in vivo and irradiated by UV, the density of bacteria and the inflammatory level (judging from the number of neutrophils) decreased significantly. Moreover, formation of neo blood vessels surrounding the implants was observed after implantation for 7 days. These results reveal that the photoresponsive multilayers endow the implants with multifunctions of simultaneous antibiofilm and tissue integration, shedding light for applications in surface modification of implants in particular for long-term use.

Series of In Situ Photoinduced Polymer Graftings for Sensitive Detection of Protein Biomarkers via Cascade Amplification of Liquid Crystal Signals

Developing of new polymeric materials for the sensitive and rapid detection of trace protein biomarkers has attracted increasing attention in biomedical fields. Herein, series of in situ photoinduced polymer graftings were developed for sensitive detection of protein biomarkers by using featured cascade amplification of liquid crystal (LC) signals. The limit-of-detection (LOD) for native bovine serum albumin (BSA) molecules is around 10 μg/mL in a LC biosensor before signal amplification. Upon the cascade amplification using surface-grafted polymers, poly[poly(ethylene glycol) methacrylate] grafting ( s-P(PEGMA)) exhibits superior amplification ability (10⁴-fold lower than native BSA) than the other two graftings of poly(2-hydroxyethyl methacrylate) ( s-PHEMA) and poly(methacrylic acid) ( s-PMAA; 10²-fold lower than native BSA). The contact angles of water and LC on the s-P(PEGMA) grafting show significant difference in comparison with s-PHEMA and s-PMAA graftings ( p < 0.05), implying interfacial energies of the grafted polymers may dictate the orientational transition of LCs. The clinical urine samples collected from the patients with proteinuria were also used to confirm the feasibility of the polymer-amplified LC sensors for practical protein assays. The present work reveals that in situ photoinduced polymer grafting is one promising method to amplify the signals of LC biosensors for the rapid and sensitive detection of trace protein biomarkers.