Huang Zheng-Hao, Peng Shi-Wei, Hsieh Shu-Ling, Kirankumar Rajendranath, Huang Po-Feng, Chang Tsao-Ming, Dwivedi Atul Kumar, Chen Nan-Fu, Wu Hao-Ming, Hsieh Shuchen
Department of Rheumatology Immunology, Kaohsiung Armed Forced General Hospital, 2 Zhongzheng 1st Rd., Kaohsiung 80284, Taiwan.
Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
Materials (Basel). 2021 Feb 1;14(3):671. doi: 10.3390/ma14030671.
The development of polydopamine (PDA) coatings with a nanometer-scale thickness on surfaces is highly desirable for exploiting the novel features arising from the specific structure on the molecular level. Exploring the mechanisms of thin-film growth is helpful for attaining desirable control over the useful properties of materials. We present a systematic study demonstrating the growth of a PDA thin film on the surface of mica in consecutive short deposition time intervals. Film growth at each deposition time was monitored through instrumental techniques such as atomic force microscopy (AFM), water contact angle (WCA) analysis, and X-ray photoelectron spectroscopy (XPS). Film growth was initiated by adsorption of the PDA molecules on mica, with subsequent island-like aggregation, and finally, a complete molecular level PDA film was formed on the surface due to further molecular adsorption. A duration of 60-300 s was sufficient for complete formation of the PDA layer within the thickness range of 0.5-1.1 nm. An outstanding feature of PDA ultrathin films is their ability to act as a molecular adhesive, providing a foundation for constructing functional surfaces. We also explored antimicrobial applications by incorporating Ag nanoparticles into a PDA film. The Ag NPs/PDA film was formed on a surgical blade and then characterized and confirmed by SEM-EDS and XPS. The modified film inhibited bacterial growth by up to 42% on the blade after cutting through a pork meat sample.
在表面制备具有纳米级厚度的聚多巴胺（PDA）涂层对于利用分子水平上特定结构产生的新特性非常有必要。探索薄膜生长机制有助于实现对材料有用性能的理想控制。我们进行了一项系统研究，展示了在连续短沉积时间间隔内PDA薄膜在云母表面的生长情况。通过原子力显微镜（AFM）、水接触角（WCA）分析和X射线光电子能谱（XPS）等仪器技术监测每次沉积时间的薄膜生长情况。PDA分子吸附在云母上引发薄膜生长，随后形成岛状聚集，最后由于进一步的分子吸附，在表面形成完整的分子水平PDA薄膜。在0.5 - 1.1 nm的厚度范围内，60 - 300 s的时间足以使PDA层完全形成。PDA超薄膜的一个突出特点是它们能够作为分子粘合剂，为构建功能表面提供基础。我们还通过将银纳米颗粒掺入PDA薄膜中探索了抗菌应用。在手术刀刀片上形成Ag NPs/PDA薄膜，然后通过扫描电子显微镜 - 能谱仪（SEM - EDS）和XPS对其进行表征和确认。在切割猪肉样品后，改性薄膜在刀片上对细菌生长的抑制率高达42%。
