Bhagwat Shweta, Sontakke Shraddha, K Deekshith, Parte Priyanka, Jadhav Sameer
Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Department of Gamete Immunobiology, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Parel, Mumbai 400012, India.
Biomicrofluidics. 2018 Mar 29;12(2):024112. doi: 10.1063/1.5023574. eCollection 2018 Mar.
Chemotaxis, as a mechanism for sperm guidance , is an enigma which has been difficult to demonstrate. To address this issue, various devices have been designed to study sperm chemotaxis . Limitations of traditional chemotaxis devices were related to the inability to maintain a stable concentration gradient as well as track single sperm over long times. Microfluidics technology, which provides superior control over fluid flow, has been recently used to generate stable concentration gradients for investigating the chemotactic behavior of several cell types including spermatozoa. However, the chemotactic behavior of sperm has not been unequivocally demonstrated even in these studies due to the inability to distinguish it from rheotaxis, thermotaxis, and chemokinesis. For instance, the presence of fluid flow in the microchannels not only destabilizes the concentration gradient but also elicits a rheotactic response from sperm. In this work, we have designed a microfluidic device which can be used to establish both, a uniform concentration and a uniform concentration gradient in a stationary fluid. By facilitating measurement of sperm response in ascending, descending ,and uniform chemoattractant concentration, the assay could isolate sperm chemotactic response from rheotaxis and chemokinesis. The device was validated using acetylcholine, a known chemoattractant and further tested with rat oviductal fluid from the estrus phase.
趋化作用作为精子导向的一种机制，是一个难以证实的谜题。为了解决这个问题，人们设计了各种装置来研究精子趋化作用。传统趋化作用装置的局限性在于无法维持稳定的浓度梯度以及长时间追踪单个精子。微流控技术能够对流体流动提供更好的控制，最近已被用于生成稳定的浓度梯度，以研究包括精子在内的几种细胞类型的趋化行为。然而，即使在这些研究中，由于无法将精子的趋化行为与向流性、趋温性和化学动力学区分开来，精子的趋化行为仍未得到明确证实。例如，微通道中流体的存在不仅会破坏浓度梯度的稳定性，还会引发精子的向流性反应。在这项工作中，我们设计了一种微流控装置，可用于在静止流体中建立均匀浓度和均匀浓度梯度。通过便于测量精子在趋化剂浓度上升、下降和均匀时的反应，该测定方法可以将精子的趋化反应与向流性和化学动力学区分开来。该装置使用已知的趋化剂乙酰胆碱进行了验证，并进一步用发情期大鼠输卵管液进行了测试。
