A Smart Antibacterial Surface for the On-Demand Killing and Releasing of Bacteria

Significance Statement

A novel smart antibacterial surface with on-demand switchable functionalities was developed by exploring the synergistic effects of combining stimuli-responsive polymers and nanomaterials with unique topographies. This surface is based on silicon nanowire arrays modified with a pH-responsive polymer, poly(methacrylic acid) (SiNWAs-PMAA). The SiNWAs-PMAA surface could be regarded as an effective dynamic antibacterial reservoir that not only exhibited a remarkably high capacity for binding lysozyme at an acidic pH (pH 4) but also could release a majority of the adsorbed lysozyme when the pH was increased to a neutral value (pH 7). The released lysozyme molecules maintained their enzymatic activity and thus served as biocides to kill bacteria both suspended in solution and attached to the surface. More importantly, after the killing process, the dead bacteria and debris attached to the SiNWAs-PMAA surface could be readily removed by further increasing the pH to a basic value (pH 10); the “cleaned” surface could then be used to load new lysozyme for repeated applications. Specifically, the functionality of the surface (loading biocides, killing bacteria, releasing bacteria) could be simply switched via step-wise modification of the environmental pH and could be effectively maintained after several kill-release cycles.

Considering that bacterial contamination is one of the main underlying causes of tissue infections and inflammation as well as device failure and endowing surfaces with antibacterial properties have attracted great research interests, it is believed that this work contributes remarkably to this subject area by providing a new strategy to engineer multifunctional surfaces with advanced antibacterial capability of both maintaining long-term antibacterial effects and keeping the surfaces free of the accumulation of dead bacteria and debris. Moreover, this approach constitutes a design platform, not limited to the silicon nanowire arrays and poly(methacrylic acid) pair, but applicable to other combinations of porous nanomaterials and stimuli-responsive polymers.

About the author

Qian Yu is an associate professor at the College of Chemistry, Chemical Engineering and Materials Science at Soochow University, Suzhou, China. He received his PhD degree in Materials Science from Wuhan University of Technology in 2011, and then worked in the Department of Biomedical Engineering in Duke University, as a postdoctoral associate (2011-2014). In 2014, he joined Soochow University and was appointed as an associate professor. His research interests include development of stimuli-responsive polymers for applications in biomedical and biotechnology fields, nanostructural biointerfaces, and anti-biofouling surfaces. He has published published more than 40 research articles in various peer reviewed journals with a total citiaton of more than 750 times (please refer to google scholar: https://scholar.google.com/citations?user=zGxmNdIAAAAJ&hl=en).

About the author

Hong Chen is a professor at the College of Chemistry, Chemical Engineering and Materials Science at Soochow University, Suzhou, China. She earned her Ph.D. degree from Nanjing University in 2001 and worked as a postdoctral fellow at McMaster University (2001-2004). After returning back to China, she held a full professor position at Wuhan University of Technology from 2004 to 2009. In 2010, her research group moved to Soochow University, where she established Macromolecules and Biointerface Laboratory (MacBio) of Soochow University. She has been the PI of more than 10 national research projects funded by the Ministry of Science and Technology of China, the Ministry of Education of China and the National Natural Science Foundation of China, including a Major International Joint Research Project. She is the winner of National Science Fund for Distinguished Young Scholars (2011). She has been admitted as a Fellow of the Royal Society of Chemistry (FRSC) in 2014. She was a guest editor for the special issue: “Biointerfaces in China” published in 2011 and became an editor of Colloids and Surface B: Biointerfaces since 2013, after three years she became the associate editor of Polymer Chemistry. Her research interests include: surface modification and functionalization of biomaterials, interaction of protein/cell and biomaterials, hemocompatibility of biomaterials, and biological detection. She has published more than 100 research articles in various peer reviewed journals. For more detailed information, please refer to her website: macbio.suda.edu.cn.

Journal Reference

Adv Healthc Mater. 2016 Feb;5(4):449-56.

Wei T¹, Yu Q¹, Zhan W¹, Chen H¹.

College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China.

Abstract

For various human healthcare and industrial applications, endowing surfaces with the capability to not only efficiently kill bacteria but also release dead bacteria in a rapid and repeatable fashion is a promising but challenging effort. In this work, the synergistic effects of combining stimuli-responsive polymers and nanomaterials with unique topographies to achieve smart antibacterial surfaces with on-demand switchable functionalities are explored. Silicon nanowire arrays are modified with a pH-responsive polymer, poly(methacrylic acid), which serves as both a dynamic reservoir for the controllable loading and release of a natural antimicrobial lysozyme and a self-cleaning platform for the release of dead bacteria and the reloading of new lysozyme for repeatable applications. The functionality of the surface can be simply switched via step-wise modification of the environmental pH and can be effectively maintained after several kill-release cycles. These results offer a new methodology for the engineering of surfaces with switchable functionalities for a variety of practical applications in the biomedical and biotechnology fields.

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