Ghaeli Ima, de Moraes Mariana A, Beppu Marisa M, Lewandowska Katarzyna, Sionkowska Alina, Ferreira-da-Silva Frederico, Ferraz Maria P, Monteiro Fernando J
i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
INEB-Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
Molecules. 2017 Aug 18;22(8):1368. doi: 10.3390/molecules22081368.
Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.
对于生物聚合物共混物而言，混溶性是一个重要问题，它有助于通过检测相分离来分析聚合物对的行为，并改善共混物的机械和物理性能。本研究提出了一种胶原蛋白与再生丝素蛋白（RSF）的稳定单相混合物配方，通过使用盐离子诱导静电相互作用，使这两种大分子之间具有最高的混溶比。为此，基于对不同比例共混溶液相行为的观察，通过实验构建了混合物的三元相图。通过粘度测量定量证实了相图混溶区内共混溶液的混溶行为。评估共混溶液透析前后生物聚合物混合比例和盐离子的影响，揭示了离子特异性相互作用在形成含胶原蛋白和RSF共混物的凝聚层基材料中的重要性，这些材料可用于制药、药物递送和生物医学应用。此外，分别通过圆二色性（CD）和傅里叶变换红外光谱（FTIR）检测了丝素蛋白在溶液和最终固体薄膜中从无规卷曲到β折叠的构象变化。扫描电子显微镜（SEM）显示了不同比例生物复合薄膜的表面形态变化。表面接触角测量表明共混薄膜表面具有不同的疏水性能。差示扫描量热法（DSC）表明丝素蛋白β折叠结构的形成增强了最终共混薄膜的热稳定性。因此，本研究提出的新方法导致形成了生物复合薄膜，其物理化学性质可通过应用不同的组分混合比例，利用丝素蛋白的构象变化进行调节。
