Department of Biological Chemistry, Indian Association of Cultivation of Science, Jadavpur, Kolkata-700032, India.
J Phys Chem B. 2012 Oct 11;116(40):12235-44. doi: 10.1021/jp306262t. Epub 2012 Sep 28.
An N-terminally Boc (tert-butyloxycarbonyl) group-protected synthetic tripeptide (Boc-Phe-Phe-Ala-OH) has been found to form a translucent hydrogel in basic aqueous medium. This hydrogel material has been characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy, differential scanning calorimetric, X-ray diffraction (XRD), and rheological studies. FE-SEM and TEM studies have revealed the formation of a nanofibrillar network structure upon gelation. Thiol (-SH) containing ligands (amino acid/peptide) have been used to stabilize small silver nanoparticles (AgNPs), and these thiol-capped silver nanoparticles have been incorporated into this hydrogel to prepare hybrid hydrogels. Morphological study of silver nanoparticles containing a hybrid hydrogel (using TEM experiments) has indicated the nice fabrication of AgNPs along the gel nanofibers. Fabrication of nanoparticles upon the gel nanofibers is due to noncovalent interactions between the capping ligands of the nanoparticles and the peptide-based hydrogel nanofibers. Rheological investigations of these hybrid hydrogels have shown the weakening of the mechanical strength of the hydrogel after incorporation of AgNPs within the native hydrogel system. Our studies have vividly shown the dependence of the elastic modulus (G') and yield stress (σ(y)) on three factors: (a) the nature of the stabilizing ligands used for AgNPs, (b) the size of the AgNPs, and (c) the amount of AgNPs used for the preparation of hybrid hydrogel systems. Modulation of the mechanical strength of the hybrid hydrogel can be successfully achieved by varying these above-mentioned factors. This modulation of the mechanical properties keeps a future promise to make tunable soft materials with interesting properties.
一种 N 端 Boc(叔丁氧羰基)保护的合成三肽(Boc-Phe-Phe-Ala-OH)在碱性水介质中被发现形成半透明水凝胶。使用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱、差示扫描量热法、X 射线衍射(XRD)和流变学研究对这种水凝胶材料进行了表征。FE-SEM 和 TEM 研究表明,凝胶化后形成了纳米纤维网络结构。含巯基(-SH)的配体(氨基酸/肽)已被用于稳定小银纳米颗粒(AgNPs),并将这些巯基封端的银纳米颗粒掺入这种水凝胶中以制备杂化水凝胶。含杂化水凝胶的银纳米颗粒的形态研究(使用 TEM 实验)表明 AgNPs 沿着凝胶纳米纤维很好地制备。纳米颗粒在凝胶纳米纤维上的制备归因于纳米颗粒的封端配体与基于肽的水凝胶纳米纤维之间的非共价相互作用。这些杂化水凝胶的流变学研究表明,在天然水凝胶系统中掺入 AgNPs 后,水凝胶的机械强度减弱。我们的研究生动地表明,弹性模量(G')和屈服应力(σ(y))取决于三个因素:(a)用于 AgNPs 的稳定配体的性质,(b)AgNPs 的尺寸,和(c)用于制备杂化水凝胶系统的 AgNPs 的量。通过改变上述因素,可以成功调节杂化水凝胶的机械强度。这种对机械性能的调节为制造具有有趣性能的可调软材料提供了未来的承诺。