New nucleic acid testing devices to diagnose infectious diseases in resource-limited settings

Abstract

Point-of-care diagnosis based on nucleic acid testing aims to incorporate all the analytical steps, from sample preparation to nucleic acid amplification and detection, in a single device. This device needs to provide a low-cost, robust, sensitive, specific, and easily readable analysis. Microfluidics has great potential for handling small volumes of fluids on a single platform. Microfluidic technology has recently been applied to paper, which is already used in low-cost lateral flow tests. Nucleic acid extraction from a biological specimen usually requires cell filtration and lysis on specific membranes, while affinity matrices, such as chitosan or polydiacetylene, are well suited to concentrating nucleic acids for subsequent amplification. Access to electricity is often difficult in resource-limited areas, so the amplification step needs to be equipment-free. Consequently, the reaction has to be isothermal to alleviate the need for a thermocycler. LAMP, NASBA, HDA, and RPA are examples of the technologies available. Nucleic acid detection techniques are currently based on fluorescence, colorimetry, or chemiluminescence. For point-of-care diagnostics, the results should be readable with the naked eye. Nowadays, interpretation and communication of results to health professionals could rely on a smartphone, used as a telemedicine device. The major challenge of creating an "all-in-one" diagnostic test involves the design of an optimal solution and a sequence for each analytical step, as well as combining the execution of all these steps on a single device. This review provides an overview of available materials and technologies which seem to be adapted to point-of-care nucleic acid-based diagnosis, in low-resource areas.

Serological and molecular rapid diagnostic tests for Toxoplasma infection in humans and animals

“…Also, advances in nanotechnology, microfluidics, biosensors, and synthetic biology have given rise to the generation of miniature-sized laboratory systems known as "lab-on-chip" devices [129]. It can also address the demand of nucleic acid testing at the POC level that integrates all the steps from sample preparation to nucleic acid amplification and detection in a single device [130]. The advantages of multifunction microfluidic lab-on-chip technology include robustness, small sample volume, enhanced reproducibility, fast analysis, accurate quantification and automation of all steps from sample preparation to signal generation and detection.…”

Nucleic acid aptamer-based methods for diagnosis of infections

“…1) (Mok and Li, 2008;Li and Ho, 2008;Lautner et al, 2010;Qi et al, 2017;Beiranvand et al, 2017;Darbandi et al, 2017;Zhang et al, 2011). Furthermore, because nucleic acid aptamers are comprised of nucleic acids, they can be easily manipulated using isothermal nucleic acid amplification methods to enhance their sensitivities for detection of target pathogens (Magro et al, 2017;Maffert et al, 2017;Bi et al, 2017). Furthermore, because nucleic acid aptamers are comprised of nucleic acids, they can be easily manipulated using isothermal nucleic acid amplification methods to enhance their sensitivities for detection of target pathogens (Magro et al, 2017;Maffert et al, 2017;Bi et al, 2017).…”

Pooled analysis of nuclear acid sequence‐based amplification for rapid diagnosis of Mycoplasma pneumoniae infection

“…The nucleic acid detection methods that have been reported include traditional PCR, NASBA, LAMP, and others . PCR technology has been used to detect M pneumoniae infections for approximately 20 years with quite a few limitations, such as the fact that the PCR inhibitors in samples may result in false‐negative results; contamination can easily lead to false positives; it is relative difficult to obtain high quality samples; and the time point for sampling impacts results.…”

“…For instance, to reach 10 6 amplification, PCR requires 20 cycles, while only 4‐5 cycles are needed for NASBA. Moreover, the mismatching rate is low and the cycle is shorter for NASBA than RT‐PCR . Therefore, it is worth exploring the diagnostic value of NASBA for M pneumoniae infections.…”