FBK-Fondazione Bruno Kessler, Center for Sensors and Devices, via Sommarive, 18, I-38123, Trento, Italy; Consiglio Nazionale delle Ricerche, Istituto di Biofisica, via alla Cascata 56/C, I-38123, Trento, Italy.
FBK-Fondazione Bruno Kessler, Center for Sensors and Devices, via Sommarive, 18, I-38123, Trento, Italy.
Colloids Surf B Biointerfaces. 2024 Jan;233:113627. doi: 10.1016/j.colsurfb.2023.113627. Epub 2023 Oct 31.
Exosomes are small extracellular vesicles well-studied both as cell signaling elements and as source of highly informative biomarkers, in particular microRNAs. Standard techniques for exosome isolation are in general scarcely efficient and give low purity vesicles. New techniques combining microfluidics with suitable functionalized surfaces could overcome these disadvantages. Here, different functional surfaces aimed at exosomes capture are developed thank to the functionalization of silicon oxide substrates. Charged surfaces, both positive and negative, neutral and immunoaffinity surfaces are characterized and tested in functional assays with both exosome mimicking vesicles and exosomes purified from cell supernatants. The different surfaces showed promising properties, in particular the negatively-charged surface could capture more than 4 × 10 exosomes per square centimeter. The captured exosomes could be recovered and their biomarker cargo analyzed. Exosomal microRNAs were successfully analyzed with RT-PCR, confirming the good performances of the negatively-charged surface. The best-performing functionalization could be easily moved to microdevice surfaces for developing modular microfluidic systems for on-chip isolation of exosomes, to be integrated in simple and fast biosensors aimed at biomarker analysis both in clinical settings and in research.
外泌体是一种小型细胞外囊泡，作为细胞信号分子和高信息量生物标志物（特别是 microRNAs）的来源，已经得到了广泛的研究。外泌体分离的标准技术通常效率不高，得到的囊泡纯度低。将微流控技术与合适的功能化表面结合的新技术可以克服这些缺点。在这里，通过对氧化硅基底进行功能化，开发了不同的用于捕获外泌体的功能化表面。对带正电荷和负电荷的表面、中性表面和免疫亲和性表面进行了特性描述和功能测试，分别用外泌体模拟囊泡和细胞上清液中纯化的外泌体进行了测试。不同的表面显示出有前景的特性，特别是负电荷表面可以每平方厘米捕获超过 4×10 个外泌体。捕获的外泌体可以被回收，并对其生物标志物进行分析。通过 RT-PCR 成功分析了外泌体中的 microRNAs，证实了负电荷表面的良好性能。表现最好的功能化可以很容易地转移到微器件表面，用于开发用于外泌体芯片分离的模块化微流控系统，以集成在简单快速的生物传感器中，用于临床和研究中的生物标志物分析。
