Oriented suspension mechanics with application to improving flow linear dichroism spectroscopy.
Oriented suspension mechanics with application to improving flow linear dichroism spectroscopy.
复制标题
定向悬浮力学应用于改进流动线性二色性光谱。
DOI：
10.1098/rspa.2019.0184
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Cupples G
中科院分区：
文献类型：
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作者：
Cupples G
流动线性二色性是一种生物物理光谱技术，其利用悬浮液中细长颗粒的剪切诱导排列。出于优化这种技术的灵敏度的广泛目标，更具体地说，由一个手持的合成生物技术原型的水虱病原体检测，稳定和振荡的压力驱动的通道流动和取向动力学的细长的微观纤维悬浮液的模型开发。该模型耦合的Fokker-Planck方程的布朗悬浮液与窄通道流方程，后者修改，以纳入机械各向异性引起的颗粒。线性二向色性信号通过将分布函数的垂直分量经由适当的公式积分来估计，该公式考虑了取向的双轴性质。对于通过结合M13噬菌体进行病原体检测的具体应用，发现通道深度的增加在改善线性二色性信号方面比通道宽度的增加更显著。将通道深度增加到2 mm，压力梯度增加到5 × 104 Pa m− 1，基本上可以最大限度地提高对齐。在适当的频率下，振荡流可以产生与定常流几乎相等的取向，这在小样品体积的分析中具有重要的潜在实用价值。
Flow linear dichroism is a biophysical spectroscopic technique that exploits the shear-induced alignment of elongated particles in suspension. Motivated by the broad aim of optimizing the sensitivity of this technique, and more specifically by a hand-held synthetic biotechnology prototype for waterborne-pathogen detection, a model of steady and oscillating pressure-driven channel flow and orientation dynamics of a suspension of slender microscopic fibres is developed. The model couples the Fokker–Planck equation for Brownian suspensions with the narrow channel flow equations, the latter modified to incorporate mechanical anisotropy induced by the particles. The linear dichroism signal is estimated through integrating the perpendicular components of the distribution function via an appropriate formula which takes the biaxial nature of the orientation into account. For the specific application of pathogen detection via binding of M13 bacteriophage, it is found that increases in the channel depth are more significant in improving the linear dichroism signal than increases in the channel width. Increasing the channel depth to 2 mm and pressure gradient to 5 × 104Pa m−1essentially maximizes the alignment. Oscillating flow can produce nearly equal alignment to steady flow at appropriate frequencies, which has significant potential practical value in the analysis of small sample volumes.