Shafi Hasham, Lora Andrea J, Aggarwal Saurabh, Infanger David W, Lawrence Brian D, Mansour Heidi M
Florida International University Center for Translational Science, Port St. Lucie, Florida 34987, United States.
Herbert Wertheim College of Medicine, Department of Cellular & Molecular Medicine, Florida International University, Miami, Florida 33199, United States.
ACS Omega. 2025 Jan 14;10(3):2762-2777. doi: 10.1021/acsomega.4c08514. eCollection 2025 Jan 28.
SDP-4 is a soluble silk fibroin-derived protein hydrolysate extracted from the silkworm cocoon and is a novel first-in-class biopolymer that is biodegradable, biocompatible, and shown to have regenerative properties. SDP-4 is currently used as a commercial wetting agent in topical eye drops, but it has also been shown to have anti-inflammatory properties that could be utilized in other biomedical applications. The purpose of this study was to comprehensively characterize the physicochemical properties that are necessary to design formulations and examine cell viability in response to varying doses of SDP-4 on different human cell types, with a particular attention toward respiratory applications. Lyophilized SDP-4 powder was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, differential scanning calorimetry (DSC), hot-stage microscopy (HSM), Karl Fisher (KF) coulometric titration, Raman spectrometry, confocal Raman microscopy (CRM), and Fourier transform infrared microscopy. The lyophilized powder exhibited a nonuniform, angular glassy flake morphology with uniform chemical composition and minimal moisture uptake when tested under varying humidity conditions. Crystalline character was evident through birefringence at ambient temperature which changed during phase transitions, as evidenced through qualitative and quantitative assessments. Dose ranging SDP-4 biocompatibility studies on different human lung cells, nasal cells, skin cells, and brain cells was assessed by the in vitro cell viability assay. Assay results showed that cell viability was maintained at the various doses studied for different human cell types. The transepithelial resistance (TEER) assay showed that SDP-4 leads to transient fluctuations in cell membrane integrity and barrier tightness, followed by a recovery phase as cells adapt or repair the junctions. These findings demonstrate that SDP-4 is biocompatible with different types of human cells and safe at all of the doses studied. The unique physicochemical properties of SDP-4 revealed in this study demonstrate its favorable formulating ability for a variety of potential therapeutic applications.
SDP - 4是一种从蚕茧中提取的可溶性丝素蛋白衍生蛋白水解物，是一种新型的一流生物聚合物，具有生物可降解性、生物相容性，并显示出具有再生特性。SDP - 4目前在局部滴眼剂中用作商业润湿剂，但也已显示出具有抗炎特性，可用于其他生物医学应用。本研究的目的是全面表征设计制剂所需的物理化学性质，并研究不同剂量的SDP - 4对不同人类细胞类型的细胞活力的影响，特别关注呼吸应用。通过扫描电子显微镜（SEM）、能量色散X射线（EDX）光谱、差示扫描量热法（DSC）、热台显微镜（HSM）、卡尔费休（KF）库仑滴定法、拉曼光谱法、共聚焦拉曼显微镜（CRM）和傅里叶变换红外显微镜对冻干的SDP - 4粉末进行了表征。冻干粉末呈现出不均匀的、有棱角的玻璃状薄片形态，在不同湿度条件下测试时化学成分均匀且吸湿最少。通过常温下的双折射可以明显看出结晶特性，在相变过程中双折射会发生变化，定性和定量评估都证明了这一点。通过体外细胞活力测定评估了不同剂量范围的SDP - 4对不同人类肺细胞、鼻细胞、皮肤细胞和脑细胞的生物相容性研究。测定结果表明，对于不同的人类细胞类型，在所研究的各种剂量下细胞活力均得以维持。跨上皮电阻（TEER）测定表明，SDP - 4会导致细胞膜完整性和屏障紧密性出现短暂波动，随后随着细胞适应或修复连接而进入恢复阶段。这些发现表明，SDP - 4与不同类型的人类细胞具有生物相容性，并且在所研究的所有剂量下都是安全的。本研究中揭示的SDP - 4独特的物理化学性质表明其在各种潜在治疗应用中具有良好的制剂形成能力。
