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  1. Bacterial meningitis, an infection of the membranes (meninges) and cerebrospinal fluid (CSF) surrounding the brain and spinal cord, is one of the major causes of death and disability worldwide. Higher case-fatality rates and short survival times have been reported in developing countries. Hence, a quick, straightforward, and low-cost approach is in great demand for the diagnosis of meningitis. In this research, a microfluidic fully paper-based analytical device (μFPAD) integrated with loop-mediated isothermal amplification (LAMP) and ssDNA-functionalized graphene oxide (GO) nano-biosensors was developed for the first time for a simple, rapid, low-cost, and quantitative detection of the main meningitis-causing bacteria, Neisseria meningitidis ( N. meningitidis ). The results can be successfully read within 1 hour with the limit of detection (LOD) of 6 DNA copies per detection zone. This paper device also offers versatile functions by providing a qualitative diagnostic analysis ( i.e. , a yes or no answer), confirmatory testing, and quantitative analysis. These features make the presented μFPAD capable of a simple, highly sensitive, and specific diagnosis of N. meningitis . Furthermore, this microfluidic approach has great potential in the rapid detection of a wide variety of different other pathogens in low-resource settings. 
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  2. Hybrid microfluidic systems that are composed of multiple different types of substrates have been recognized as a versatile and superior platform, which can draw benefits from different substrates while avoiding their limitations. This review article introduces the recent innovations of different types of low-cost hybrid microfluidic devices, particularly focusing on cost-effective polymer- and paper-based hybrid microfluidic devices. In this article, the fabrication of these hybrid microfluidic devices is briefly described and summarized. We then highlight various hybrid microfluidic systems, including polydimethylsiloxane (PDMS)-based, thermoplastic-based, paper/polymer hybrid systems, as well as other emerging hybrid systems (such as thread-based). The special benefits of using these hybrid systems have been summarized accordingly. A broad range of biological and biomedical applications using these hybrid microfluidic devices are discussed in detail, including nucleic acid analysis, protein analysis, cellular analysis, 3D cell culture, organ-on-a-chip, and tissue engineering. The perspective trends of hybrid microfluidic systems involving the improvement of fabrication techniques and broader applications are also discussed at the end of the review. 
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    A low-cost, sensitive, and disposable paper-based immunosensor for instrument-free colorimetric detection of pancreatic cancer biomarker PEAK1 was reported for the first time by capitalizing the catalytic properties of gold nanoparticles in colour dye degradation. This simple signal amplification method enhances the detection sensitivity by about 10 fold. 
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    The requirement of on-demand microfluidic pumps and instrument-free readout methods remains a major challenge for the development of microfluidics. Herein, a new type of microfluidic platform, an on-demand photothermal microfluidic pumping platform, has been developed using an on-chip nanomaterial-mediated photothermal effect as novel and remotely tunable microfluidic driving force. The photothermal microfluidic pumping performance can be adjusted remotely by tuning the irradiation parameters, without changing on-chip parameters or replacing enzymes or other reagents. In contrast to graphene oxide, Prussian blue nanoparticles with higher photothermal conversion efficiency were used as the model photothermal agent to demonstrate the proof of concept. The on-chip pumping distance is linearly correlated with both the irradiation time and the nanomaterial concentration. The applications of photothermal microfluidic pumping have been demonstrated in multiplexed on-chip transport of substances, such as gold nanoparticles, and visual quantitative bar-chart detection of cancer biomarkers without using specialized instruments. Upon contact-free irradiation using a laser pointer, a strong on-chip nanomaterial-mediated photothermal effect can serve as a robust and remotely tunable microfluidic pump in a PMMA/PDMS hybrid bar-chart chip to drive ink bars in a visual quantitative readout fashion. This is the first report on a photothermal microfluidic pumping platform, which has great potential for various microfluidic applications. 
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