An overview and future perspectives of user-friendly microfluidic devices have been reported in terms of practical sample preparation in point-of-care testing.

Molecular diagnostics can provide a powerful diagnostic tool since it can detect pathogens with high sensitivity, but complicated sample preparation procedures limit its widespread use as an on-site detection tool that relies on the skilled person and external equipment. To resolve these limitations, we report a solid-phase nucleic acid purification using a finger-actuated microfluidic device, which can control a set amount of flow regardless of differences in end-users. To increase the recovery rate, a finger-actuated reciprocator was newly developed and integrated into the microfluidic device that can efficiently react with silica microbeads and reagents. After verifying the finger-actuated microfluidic reciprocator, the effect of the reciprocating flow on the recovery rate was assessed to purify the standard DNA of the hepatitis B virus (HBV). The recovery rate was increased up to ∼50% and 955 to 955 000 IU mL⁻¹ of HBV standard DNA was successfully purified and detected by a real-time polymerase chain reaction. Furthermore, the proposed microfluidic device was exploited to purify the HBV DNA from the patient's blood plasma samples.

Although numerous studies have been conducted to realize ideal point-of-care testing (POCT), the development of a user-friendly and user-independent power-free microfluidic platform is still a challenge. Among various methods, the finger-actuation method shows a promising technique that provides a user-friendly and equipment-free way of delivering fluid in a designated manner. However, the design criteria and elaborate evaluation of the fluid behavior of a pushbutton-activated microfluidic device (PAMD) remain a critical bottleneck to be widely adopted in various applications. In this study, we have evaluated the fluid behavior of the PAMD based on various parameters, such as pressing velocity and depth assisted by a press machine. We have further developed a user-friendly and portable pressing block that reduces user variation in fluid behavior based on the evaluation.

In this paper, we have developed a novel cell-free biosensor based on a multiplexed pushbutton-activated microfluidic device (mPAMD) that enables simultaneous detection of multiple 16S rRNAs of pathogens in a single device. The multi-step target-responsive cell-free protein synthesis process was seamlessly integrated into a single microfluidic device with an intuitive finger-pumping mechanism, allowing simultaneous mixing, aliquoting, and detection of 16S rRNAs through the production of reporter proteins. The mPAMD incorporates multiplexed detection zones with pathogen-specific probes to enable the identification of multiple 16S rRNAs that allow a simple and intuitive diagnostic platform for cell-free biosensors. Microchannels were designed and optimized to achieve efficient sample mixing and even distribution of common reagents, ensuring uniform reaction conditions across all reaction channels. The developed system achieved a detection limit for 16S rRNA ranging from 1.69 to 7.39 pM, corresponding to approximately 10⁴ to 10⁵ CFU/mL of pathogens. These results address the growing demand for an accessible multiplexed diagnostic system while ensuring high sensitivity and specificity.