秀麗隱桿線蟲(Caenorhabditis elegans)是目前已知最小的多細胞無脊椎動物之一。自40年前由Sydney Brenner博士[1]發現後，即成為基因工程、神經科學、遺傳學與製藥領域最有效的一種動物模型。相較於其他更高等複雜的動物模型，線蟲的優勢在於體型小(~1 mm)、透明、基因完全定序、具備少量神經元(302)、生命週期短(~2.5天)且飼養繁殖容易。雖然線蟲對於外在環境的變化非常敏感，然而相關其運動力學的研究仍相當缺乏且不易達成。因此本研究藉由一套簡易的微液滴系統評估線蟲與外在環境的關係，最終希望能提供線蟲相關研究量化之生物力學數據。在本研究中為了定義線蟲游動環境的黏度，利用微觀粒子影像流速儀(μPIV)的原理配合布朗運動(Brownian motion)發展出一套微量樣品的黏度量測技術，大幅改善目前市面上傳統黏度計的缺點，例如微量化樣品(<1μL)、可拋棄式載具、大範圍黏度(1cp~1664cp)、價格便宜、非侵入式測量等。在此研究中線蟲的生物力學分析，其是將線蟲挑入矩陣狀的模穴中，利用矩陣狀的模穴得到了多隻線蟲游動影像，此法之優點為節省實驗時間、勞動人力、節省實驗花費、限制線蟲於單一模穴中避免影像重疊、可大量平行量測，定義線蟲在不同粘度下的游動參數如蟲體曲率分佈、頻率、攻角。與分析線蟲於佈滿粒子之線蟲生長基中之游動影像，建立其在此環境中的模型，利用粒子影像流速儀的原理分析造成之流場變化，可得隨著時間產生之推進力以及運動能量輸出的變化。以上這些分析可用來評估各種實驗過的線蟲體內的肌肉以及神經是否有造成改變，亦或量化比較這些參數在不同線蟲株之間的關係以做為未來在神經學、基因工程與藥物開發之參考依據。

Caenorhabditis (C.) elegans is known as one of smallest invertebrate animals. The round worm C. elegans has been proven to be a powerful model genetic system[1] for a wide variety of neurobiological purposes. In contrast to the lab mice, C. elegans is an important animal model in genetics, neurobiology, and drug screening due to fast reproduction, handful neurons (302), short body length (~1 mm), a short life cycle (2.5 days), an explicitly-defined neural network[2], fully sequenced genome, and optical transparency. The nematode C. elegans is sensitive to environmental stimulation. However, interactions between biomechanical responses of the nematode and different environmental stimuli are difficult to reach. In this thesis, a simple micro-droplet system was employed as a research tool to study the locomotive behaviors of C. elegans in response to environmental stimuli. The system featured confined space with minimum interference, low cost, simple microfabrication, massively parallel measurement and prevent image overlapping. In this research, μPIV diffusometry was used to assist the measurements of liquid viscosity by Brownian motion. The technique was also used to correlate the viscosity change of dextran solutions and the kinematics of the micro-swimmer, C. elegans. The advantages of this technique include small volume (< 1μL), noninvasiveness, ease of use, and low cost. The good agreement between the data measured from the μPIV system and a commercial viscometer validated the practicability of the approach. A broad range of viscosity measurements( >〖10〗^3 mPa∙s) were investigated. The demonstration confirms the possible use of the technique in other biological applications that requires broad-range and small-volume measurement capabilities for viscosity. In this research, biomechanical analyses out of the worm undulatory kinematics were also achieved based on the same micro-droplet system. Spatio-temporal contour of body curvature, bending frequency, and angle of attack were measured successfully. The droplet system combined with μPIV provided a unique measure to assess the propulsive force and power of C. elegans. Biomechanical properties of the nematode C. elegans can be eventually used to quantify the phenotypes of normal nematodes and mutants carrying neural and muscular disease. The results will benefit pharmacology, neurology, and genetics and provide useful information for future applications.

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