Building an optical filtration function into a microfluidic chip is a promising way of simplifying the optical detection system of a microfluidic device. In this paper, a PDMS microfluidic chip filter that is capable of transmitting chlorophyll fluorescence and blocking interfering light in the visible wavelength range was developed for living algae detection with a smartphone. The chip was fabricated by sealing a layer of crystal violet solution in a PDMS layer on the top of the Sudan II-doped PDMS slab, which has a straight microchannel. Optimum dye concentrations and thicknesses for the crystal violet solution layer and Sudan II-doped PDMS slab were investigated and determined by spectrum measurements. It was found that the cut-on range of this integrated microfluidic chip is extended to about 625 nm and the transmittance in the chlorophyll fluorescence range (650 nm to 710 nm) is as high as 95%, when 25 mg L⁻¹ Sudan II-doped PDMS slab (with a 3 mm thickness) and 2 mg L⁻¹ crystal violet solution (with a 0.3 mm thickness) were used. Living algae detection using this chlorophyll-fluorescence-filtering PDMS microfluidic chip and a smartphone-based imaging platform was achieved, and the results compared favorably with those using a commercial filter.

中文翻译：

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使用 PDMS 液体叶绿素荧光微流控芯片过滤器和智能手机进行活藻检测

在微流控芯片中构建光学过滤功能是一种简化微流控设备光学检测系统的有前途的方法。在本文中，开发了一种能够传输叶绿素荧光并阻挡可见波长范围内的干扰光的 PDMS 微流控芯片滤光片，用于通过智能手机进行活体藻类检测。该芯片是通过在苏丹 II 掺杂的 PDMS 板顶部的 PDMS 层中密封一层结晶紫溶液制成的，该板具有直的微通道。通过光谱测量研究和确定结晶紫溶液层和苏丹 II 掺杂 PDMS 板的最佳染料浓度和厚度。^使用了-1苏丹 II 掺杂的 PDMS 板（厚度为 3 mm）和 2 mg L ^-1结晶紫溶液（厚度为 0.3 mm）。使用这种叶绿素荧光过滤 PDMS 微流控芯片和基于智能手机的成像平台实现了活藻检测，结果与使用商业过滤器的结果相比具有优势。