Biomedical Engineering Research Center , Medical School of Ningbo University , Ningbo 315211 , Zhejiang , P. R. China.
The Affiliated Hospital of Medical School of Ningbo University , Ningbo 315020 , Zhejiang , P. R. China.
ACS Sens. 2019 Sep 27;4(9):2481-2490. doi: 10.1021/acssensors.9b01109. Epub 2019 Sep 6.
Intelligent contactless microfluidic pumping strategies have been increasingly desirable for operation of lab-on-a-chip devices. Herein, we present a photothermal microfluidic pumping strategy for on-chip multiplexed cargo transport in a contactless and spatiotemporally controllable fashion based on the application of near-infrared laser-driven photothermal effect in microfluidic paper-based devices (μPDs). Graphene oxide (GO)-doped thermoresponsive poly(-isopropylacrylamide)-acrylamide hydrogels served as the photothermally responsive cargo reservoirs on the μPDs. In response to remote contactless irradiation by an 808 nm laser, on-chip phase transition of the composite hydrogels was actuated in a switchlike manner as a result of the photothermal effect of GO, enabling robust on-chip pumping of cargoes from the hydrogels to predefined arrays of reaction zones. The thermal imaging technique was employed to monitor the on-chip photothermal pumping process. The microfluidic pumping performance can be spatiotemporally controlled in a quantitative way by remotely tuning the laser power, irradiation time, and GO concentration. The pumping strategy was exemplified by FeCl and horseradish peroxidase as the model cargoes to implement on-chip Prussian blue- and 3,3',5,5'-tetramethylbenzidine-based colorimetric reactions, respectively. Furthermore, multiplexed on-demand microfluidic pumping was achieved by flexibly adjusting the irradiation pathway and the microfluidic pattern. The new microfluidic pumping strategy shows great promise for diverse microfluidic applications due to its flexibility, high integratability into lab-on-a-chip devices, and contactless and spatiotemporal controllability.
智能非接触微流控泵送策略越来越受到人们的青睐，用于操作芯片实验室设备。在此，我们提出了一种基于近红外激光驱动微流控纸基器件（μPDs）中的光热效应的非接触式和时空可控的光热微流控泵送策略，用于在芯片上进行多路货物运输。氧化石墨烯（GO）掺杂的温敏聚（异丙基丙烯酰胺）-丙烯酰胺水凝胶作为μPDs上的光热响应货物储存库。在 808nm 激光的远程非接触照射下，由于 GO 的光热效应，复合水凝胶的芯片上相转变以开关方式触发，从而能够将货物从水凝胶中强力泵送至预定的反应区阵列中。采用热成像技术来监测芯片上的光热泵送过程。通过远程调节激光功率、辐照时间和 GO 浓度，可以定量地对微流控泵送性能进行时空控制。该泵送策略以 FeCl 和辣根过氧化物酶作为模型货物为例，分别实现了芯片上普鲁士蓝和 3,3',5,5'-四甲基联苯胺的比色反应。此外，通过灵活调整辐照路径和微流控图案，可以实现多路按需微流控泵送。由于其灵活性、高度集成到芯片实验室设备中的能力以及非接触式和时空可控性，这种新的微流控泵送策略在各种微流控应用中具有广阔的应用前景。
