Zhang Liting, Cao Xiaodan, Wang Lu, Zhao Xueyan, Zhang Songping, Wang Ping
Biomedical Nanotechnology Center, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
Analyst. 2015 Jun 21;140(12):4105-13. doi: 10.1039/c5an00054h. Epub 2015 Apr 20.
A paper-based colorimetric biosensor suitable for point-of-care bioassay of blood samples is developed using highly stable enzyme thin-film coatings confined within inkjet printed polymeric microwells. The microwells are developed through a simple one-step inkjet printing of hydrophobic polystyrene on paper, with walls formed by the polymer that fills the gaps inside the paper body. The microwells can also be patterned to be interlinked with printed microchannels for multiplex bioassays. Thin film enzyme coatings confined within the microwells are then constructed, thereby constituting biosensors that work like traditional microwell plates, yet allow easy colorimetric readouts with naked eyes or portable devices, such as smart phones. The efficiency of the paper-based sensor was demonstrated for colorimetric assays of glucose and lactate, both as individual analytes or mixed, as well as samples with red blood cells. Such sensors showed good sensitivities within the concentration ranges of the analytes in human blood (0.5-10 mM), with a visible sensitivity of <0.5 mM detectable by naked eyes for a sample size as small as 1 μL. More accurate digital readouts were shown to be feasible with computerized scanners or smartphones. The thin-film coating format affords the paper biosensors an extended lifetime, and they could retain 100% performance over 6 months of storage at room temperature, or up to one month heated at 50 °C, which promises refrigeration-free storage of the sensor. The simple preparation, high enzyme stability and ease-of-use of the paper-based sensor promise low-cost and reliable point-of-care multiplex bioassay for biomedical diagnostics.
一种适用于血液样本即时检测生物分析的纸质比色生物传感器被开发出来，它使用了限制在喷墨打印聚合物微孔内的高度稳定的酶薄膜涂层。这些微孔是通过在纸上简单地一步喷墨打印疏水性聚苯乙烯而形成的，其壁由填充在纸体内部间隙的聚合物构成。这些微孔还可以被图案化，以便与打印的微通道相互连接，用于多重生物分析。然后构建限制在微孔内的薄膜酶涂层，从而构成了类似传统微孔板工作的生物传感器，但可以通过肉眼或便携式设备（如智能手机）轻松进行比色读数。该纸质传感器在葡萄糖和乳酸的比色分析中得到了验证，无论是单独的分析物还是混合的，以及含有红细胞的样本。这种传感器在人体血液中分析物的浓度范围内（0.5 - 10 mM）表现出良好的灵敏度，对于小至1 μL的样本，肉眼可检测到的可见灵敏度<0.5 mM。使用计算机扫描仪或智能手机可以实现更准确的数字读数。薄膜涂层形式赋予纸质生物传感器更长的使用寿命，它们在室温下储存6个月或在50°C加热长达1个月的情况下可以保持100%的性能，这保证了传感器无需冷藏储存。这种纸质传感器的简单制备、高酶稳定性和易用性为生物医学诊断提供了低成本且可靠的即时多重生物分析。
