A power-free microfluidic device for the detection of hepatitis B virus in resource-limited settings

Rapid on-site nucleic acid testing plays a critical role in the prevention, diagnosis, and treatment of infectious diseases. Although real-time fluorescence polymerase chain reaction (PCR) technique, as the gold standard method, is widely used for nucleic acid quantification, its reliance on complex instrumentation and trained personnel in centralized laboratories presents significant challenges in applications such as rapid home-based self-testing or screening in remote areas. Therefore, there is an urgent need to develop miniaturized, low-cost, user-friendly, and high-performance point-of-care testing (POCT) devices for nucleic acid detection to meet the demands of infectious pathogen screening in resource-limited settings.

In this study, a low-cost and power-free microfluidic device (PFMD), which realized contamination-free analysis with 'sample-in-visual-result-out' capability, was developed. The proposed system integrated rapid extraction and enrichment of nucleic acid from serum samples, isothermal nucleic acid amplification, and visual readout of lateral flow test strips. The entire detection process was completed within 40 min. Power-free isothermal amplification was enabled by a disposable warm patch. The detection performance of the PFMD was evaluated using nucleic acid standards of hepatitis B virus (HBV) and other pathogens, as well as clinical serum samples from suspected hepatitis B cases. The PFMD successfully accomplished rapid magnetic bead-based nucleic acid extraction and achieved a lower limit of detection of 3.04 copies/μL. The clinical experimental results of the device were consistent with those obtained by quantitative PCR and real-time fluorescent loop-mediated isothermal amplification (LAMP) methods, with 100 % diagnostic sensitivity and 100 % diagnostic specificity.

This work presents an integrated, portable, low-cost, and power-free POCT method for nucleic acid detection, which demonstrates rapid diagnostic capabilities for complex clinical samples and exhibits outstanding sensitivity and specificity. Clinical validation confirms that the proposed method and device are well-suited for on-site rapid screening of infectious diseases such as hepatitis B, particularly in resource-constrained settings without access to electricity or trained professionals.