Haider Md Kaiser, Ullah Azeem, Sarwar Muhammad Nauman, Yamaguchi Takumi, Wang Qianyu, Ullah Sana, Park Soyoung, Kim Ick Soo
Nano Fusion Technology Research Group, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, Tokida 3-15-1, Ueda, Nagano 386-8567, Japan.
Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
Polymers (Basel). 2021 Feb 28;13(5):748. doi: 10.3390/polym13050748.
Concerning the environmental hazards owing to the chemical-based synthesis of silver nanoparticles (AgNPs), this study aimed to investigate the possibility of synthesizing AgNPs on the surface polyacrylonitrile (PAN) nanofibers utilizing biomacromolecule lignin. SEM observations revealed that the average diameters of the produced nanofibers were slightly increased from ~512 nm to ~673 nm due to several factors like-swellings that happened during the salt treatment process, surface-bound lignin, and the presence of AgNPs. The presence of AgNPs was validated by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The amount of synthesized AgNPs on PAN nanofibers was found to be dependent on both precursor silver salt and reductant lignin concentration. Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectra confirm the presence of lignin on PAN nanofibers. Although the X-ray diffraction pattern did not show any AgNPs band, the reduced intensity of the stabilized PAN characteristics bands at 2θ = 17.28° and 29.38° demonstrated some misalignment of PAN polymeric chains. The water contact angle (WCA) of hydrophobic PAN nanofibers was reduced from 112.6 ± 4.16° to 21.4 ± 5.03° for the maximum AgNPs coated specimen. The prepared membranes exhibited low thermal stability and good swelling capacity up to 20.1 ± 0.92 g/g and 18.05 ± 0.68 g/g in distilled water and 0.9 wt% NaCl solution, respectively. Coated lignin imparts antioxidant activity up to 78.37 ± 0.12% at 12 h of incubation. The resultant nanofibrous membranes showed a proportional increase in antibacterial efficacy with the rise in AgNPs loading against both Gram-positive and Gram-negative bacterial strains by disc diffusion test (AATCC 147-1998). Halos for maximum AgNPs loading was calculated to 18.89 ± 0.15 mm for and 21.38 ± 0.17 mm for . An initial burst release of silver elements within 24 h was observed in the inductively coupled plasma-atomic emission spectrometry (ICP-AES) test, and the release amounts were proportionally expansive with the increase in Ag contents. Our results demonstrated that such types of composite nanofibers have a strong potential to be used in biomedicine.
鉴于基于化学合成银纳米颗粒（AgNPs）所带来的环境危害，本研究旨在探讨利用生物大分子木质素在聚丙烯腈（PAN）纳米纤维表面合成AgNPs的可能性。扫描电子显微镜（SEM）观察结果显示，由于盐处理过程中发生的溶胀、表面结合的木质素以及AgNPs的存在等多种因素，所制备纳米纤维的平均直径从约512 nm略有增加至约673 nm。通过透射电子显微镜（TEM）和X射线光电子能谱（XPS）分析验证了AgNPs的存在。发现PAN纳米纤维上合成的AgNPs的量取决于前体银盐和还原剂木质素的浓度。傅里叶变换红外衰减全反射（FTIR-ATR）光谱证实了PAN纳米纤维上木质素的存在。尽管X射线衍射图谱未显示任何AgNPs谱带，但在2θ = 17.28°和29.38°处稳定的PAN特征谱带强度降低表明PAN聚合物链存在一定程度的错位。对于最大AgNPs包覆的样品，疏水性PAN纳米纤维的水接触角（WCA）从112.6±4.16°降至21.4±5.03°。所制备的膜表现出较低的热稳定性，在蒸馏水和0.9 wt% NaCl溶液中的溶胀能力分别高达20.1±0.92 g/g和18.05±0.68 g/g。包覆的木质素在孵育12 h时具有高达78.37±0.12%的抗氧化活性。通过纸片扩散法（AATCC 147 - 1998）测试，所得纳米纤维膜对革兰氏阳性和革兰氏阴性细菌菌株的抗菌效果随AgNPs负载量的增加呈比例增加。对于最大AgNPs负载量，金黄色葡萄球菌的抑菌圈计算为18.89±0.15 mm，大肠杆菌的抑菌圈计算为21.38±0.17 mm。在电感耦合等离子体原子发射光谱（ICP-AES）测试中观察到银元素在24 h内有初始的突发释放，释放量随Ag含量的增加呈比例增加。我们的结果表明，这类复合纳米纤维在生物医学领域具有很强的应用潜力。
