Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201, USA.
Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR 97201, USA.
Biosensors (Basel). 2024 Sep 25;14(10):456. doi: 10.3390/bios14100456.
Bacterial membrane vesicle (BMV) nanoparticles are secreted naturally by bacteria throughout their lifecycle and are a rich source of biomarkers from the parent bacteria, but they are currently underutilized for clinical diagnostic applications, such as pathogen identification, due to the time-consuming and low-yield nature of traditional recovery methods required for analysis. The recovery of BMVs is particularly difficult from complex biological fluids. Here, we demonstrate a recovery method that uses dielectrophoretic (DEP) forces generated on electrokinetic microfluidic chips to isolate and analyze BMVs from human plasma. DEP takes advantage of the natural difference in dielectric properties between the BMVs and the surrounding plasma fluid to quickly and consistently collect these particles from as little as 25 µL of plasma. Using DEP and immunofluorescence staining of the LPS biomarker carried on BMVs, we have demonstrated a lower limit of detection of 4.31 × 10 BMVs/mL. The successful isolation of BMVs from human plasma using DEP, and subsequent on-chip immunostaining for biomarkers, enables the development of future assays to identify the presence of specific bacterial species by analyzing BMVs from small amounts of complex body fluid.
细菌膜泡 (BMV) 纳米颗粒是细菌在整个生命周期中自然分泌的，是母体细菌生物标志物的丰富来源，但由于传统分析方法需要耗时且产量低，因此它们在临床诊断应用（如病原体鉴定）中尚未得到充分利用。从复杂的生物流体中回收 BMV 尤其困难。在这里，我们展示了一种使用电泳（DEP）力从人血浆中分离和分析 BMV 的方法，该方法在电动微流控芯片上产生。DEP 利用 BMV 和周围血浆流体之间天然的介电性质差异，从少至 25µL 的血浆中快速、一致地收集这些颗粒。通过使用 DEP 和 BMV 上携带的 LPS 生物标志物的免疫荧光染色，我们已经证明了检测下限为 4.31×10 BMVs/mL。DEP 成功地从人血浆中分离出 BMV，随后在芯片上对生物标志物进行免疫染色，这使得能够开发未来的检测方法，通过分析来自少量复杂体液的 BMV 来鉴定特定细菌种类的存在。
