低真空驅動微流體晶片之原理與應用

Low-Vacuum-Driven Microfluidic Chips: Principles and Applications

微流體晶片已廣泛應用於生醫檢測、單細胞分析與現場快速檢驗，但傳統系統多仰賴體積龐大且價格高昂的外接幫浦與管路，限制了其攜帶性與在資源受限場域的應用。近年提出的低真空驅動（low-vacuum-driven）微流體技術，利用預先抽氣的真空腔體、真空袋或PDMS材料之氣體溶解與滲透特性，在晶片上產生穩定且可預測的負壓作為驅動力，得以實現無電源或低功耗的自驅動流體控制。本研究首先整理低真空驅動微流體之基礎理論，包括壓力驅動流體力學、PDMS除氣機制與真空釋放動態，並對比傳統注射幫浦與毛細力驅動系統之差異。接著，針對代表性應用案例進行分析，包括真空袋微流體系統於薄膜混合與現場檢測之應用、注射器輔助真空驅動微幫浦在定流量輸送上的表現，以及利用暫態真空進行細胞無剪應力載入與圖樣化培養等技術。綜合比較可知，低真空驅動架構具有系統簡化、成本降低、可攜性佳與易於整合一次性耗材等優點，但在真空保持時間、流量長時間穩定性與定量控制精度方面仍具挑戰。本研究最後提出在生醫檢測與現場診斷情境下導入低真空驅動微流體晶片之設計建議與未來研究方向，以供後續元件開發與系統整合之參考。

Microfluidic chip technology has been widely employed in biomedical diagnostics, single-cell analysis, and on-site testing; however, conventional systems typically rely on bulky and expensive external pumps and tubing, which limit portability and deployment in resource-limited settings. Recently, low-vacuum-driven microfluidics has emerged as a promising approach that exploits pre-evacuated chambers or vacuum pouches, as well as the gas solubility and permeability of polydimethylsiloxane (PDMS), to generate a stable and predictable negative pressure as the driving force, thereby enabling power-free or low-power fluidic control. In this study, we first review the fundamental principles of low-vacuum-driven microfluidic systems, including pressure-driven laminar flow, degassing mechanisms in PDMS, and the dynamics of vacuum release, and we compare them with conventional syringe-pump-based and capillary-driven systems. We then analyze representative application examples, such as the vacuum pouch microfluidic system for thin-film micromixers and on-site detection, syringe-assisted vacuum-driven micropumps providing constant flow rates, and transient on-chip vacuum for shear-free mammalian cell loading and patterning. These case studies demonstrate that low-vacuum-driven architectures offer advantages in system simplification, cost reduction, portability, and ease of integration with disposable cartridges, while challenges remain in terms of vacuum retention time, long-term flow stability, and precise quantitative control. Finally, we discuss design guidelines and future perspectives for implementing low-vacuum-driven microfluidic chips in biomedical assays and point-of-care diagnostics, aiming to support subsequent device development and system integration efforts.