Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Langmuir. 2021 Nov 9;37(44):13000-13011. doi: 10.1021/acs.langmuir.1c02062. Epub 2021 Nov 1.
Benefiting from the luxury functions of proteins, protein coatings have been extended to various applications, including tissue engineering scaffolds, drug delivery, antimicrobials, sensing and diagnostic equipment, food packaging, etc. Fast construction of protein coatings is always interesting to materials science and significant to industrialization. Here, we report a layer-by-layer (LbL) multilayer-constructed coating of tannic acid (TA) and lysozyme (Lyz), in which the secondary conformations of Lyz dominate the growth rate of the TA/Lyz coating. As well characterized by various techniques (quartz crystal microbalance with dissipation (QCM-D), circular dichroism (CD) spectra, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), contact angle, etc.), TA-induced conformational transition of Lyz to α-helices occurs at pH 8 from other secondary structures (β-sheets, β-turns, and random coils), which leads to the very fast growth of TA/Lyz with a number of deposited bilayers, with thicknesses of more than 90 nm for six bilayers. In contrast to the leading conformation of α-helices at pH 8, Lyz displayed multiple conformations (α-helices, β-sheets, β-turns, and random coils) at pH 6, which resulted in coating thicknesses of less than 30 nm for six bilayers. By the addition of NaCl, Tween 20, and urea, we further confirmed that the secondary conformations of Lyz relied greatly on the interactions between TA and Lyz and dominated the growth rate of the multilayers. We believe that these findings will help to understand the transformation of secondary conformations by TA or other polyphenols and inspire a new route to quickly build protein coatings.
得益于蛋白质的奢华功能，蛋白质涂层已经扩展到各种应用领域，包括组织工程支架、药物输送、抗菌、传感和诊断设备、食品包装等。快速构建蛋白质涂层一直是材料科学感兴趣的问题，对工业化也具有重要意义。在这里，我们报告了单宁酸（TA）和溶菌酶（Lyz）的层层（LbL）多层构建涂层，其中 Lyz 的二级构象主导 TA/Lyz 涂层的生长速率。通过各种技术（石英晶体微天平耗散（QCM-D）、圆二色性（CD）光谱、傅里叶变换红外（FTIR）光谱、原子力显微镜（AFM）、接触角等）进行了很好的表征，在 pH 8 时，TA 诱导 Lyz 发生从其他二级结构（β-折叠、β-转角和无规卷曲）到α-螺旋的构象转变，这导致 TA/Lyz 以非常快的速度生长，沉积的双层数量超过 90nm，共 6 层。与 pH 8 时的主导构象α-螺旋相比，Lyz 在 pH 6 时显示出多种构象（α-螺旋、β-折叠、β-转角和无规卷曲），导致 6 层的涂层厚度小于 30nm。通过添加 NaCl、吐温 20 和尿素，我们进一步证实了 Lyz 的二级构象很大程度上依赖于 TA 和 Lyz 之间的相互作用，并主导了多层的生长速率。我们相信这些发现将有助于理解 TA 或其他多酚引起的二级构象的转变，并为快速构建蛋白质涂层提供新的途径。
