Department Functional Colloidal Materials, Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069 Dresden, Germany.
Department Chemistry and Food Chemistry, TUD Dresden University of Technology, 01062 Dresden, Germany.
Langmuir. 2024 Aug 13;40(32):16731-16742. doi: 10.1021/acs.langmuir.4c00920. Epub 2024 Jul 29.
Dynamic attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy at both solutions and coatings of a semicrystalline silk material derived from was applied to monitor the β-sheet conformation, which is known to correlate with silk protein crystallinity. The secondary structure-sensitive Amide I band was analyzed. Two silk protein samples were studied: native-based silk buffer fibroin (NSF) was extracted from silk glands and regenerated silk fibroin (RSF) was extracted from degummed cocoons. Solutions of both NSF and RSF at 2 mg/mL featured low initial β-sheet contents of 5-12%, which further increased to 47-53% after 24 h. RSF and NSF solutions at 23 mg/mL also featured low initial β-sheet contents of 9-10%, which yet only slightly increased to 16-17% after 24 h. Coatings deposited from RSF solutions showed high surface integrity ( > 99%) after rinsing in mineralized water, enabling interfacial drug delivery applications. RSF coatings were post-treated with either formic acid (FA) or pure methanol (MeOH) vapor to showcase inducibility of crystalline domains in RSF coatings. Such coatings were loaded with the model antibiotic drugs tetracycline (TCL) and streptomycin (STRP), and the sustained release of TCL was followed in contact with (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (HEPES) buffer. RSF/TCL coatings post-treated with formic acid (FA) vapor followed by methanol (MeOH) vapor showed a significantly lower (52%) initial burst of rather hydrophobic TCL compared to untreated RSF/TCL coatings (72%), while no such significant release difference was observed for hydrophilic STRP. This was rationalized by a specific interaction between nonpolar TCL and hydrophobic crystalline RSF domains.
采用动态衰减全反射-傅里叶变换红外（ATR-FTIR）光谱法对来源于家蚕丝腺的半结晶丝材料的溶液和涂层进行研究，以监测已知与丝蛋白结晶度相关的β-折叠构象。分析了对二级结构敏感的酰胺 I 带。研究了两种丝蛋白样品：从丝腺中提取的天然基丝缓冲丝素（NSF）和从脱胶茧中提取的再生丝素（RSF）。2mg/mL 的 NSF 和 RSF 溶液的初始β-折叠含量较低，为 5-12%，24 小时后增加到 47-53%。23mg/mL 的 RSF 和 NSF 溶液的初始β-折叠含量也较低，为 9-10%，但 24 小时后仅略有增加到 16-17%。从 RSF 溶液中沉积的涂层在矿化水中冲洗后具有很高的表面完整性（>99%），可用于界面药物输送应用。RSF 涂层用甲酸（FA）或纯甲醇（MeOH）蒸气进行后处理，以展示 RSF 涂层中晶区的诱导能力。用模型抗生素药物四环素（TCL）和链霉素（STRP）对这些涂层进行负载，并在接触（4-（2-羟乙基）-1-哌嗪乙磺酸）（HEPES）缓冲液中跟踪 TCL 的持续释放。用甲酸（FA）蒸气后处理再用甲醇（MeOH）蒸气处理的 RSF/TCL 涂层与未处理的 RSF/TCL 涂层相比，疏水性 TCL 的初始突释（52%）明显降低（72%），而亲水性 STRP 则没有观察到明显的释放差异。这可以通过非极性 TCL 与疏水性结晶 RSF 域之间的特定相互作用来解释。
