Advances in developing HIV-1 viral load assays for resource-limited settings

Abstract

Commercial HIV-1 RNA viral load assays have been routinely used in developed countries to monitor antiretroviral treatment (ART). However, these assays require expensive equipment and reagents, well-trained operators, and established laboratory infrastructure. These requirements restrict their use in resource-limited settings where people are most afflicted with the HIV-1 epidemic. Inexpensive alternatives such as the Ultrasensitive p24 assay, the Reverse Transcriptase (RT) assay and in-house reverse transcription quantitative polymerase chain reaction (RT-qPCR) have been developed. However, they are still time-consuming, technologically complex and inappropriate for decentralized laboratories as point-of-care (POC) tests. Recent advances in microfluidics and nanotechnology offer new strategies to develop low-cost, rapid, robust and simple HIV-1 viral load monitoring systems. We review state-of-the-art technologies used for HIV-1 viral load monitoring in both developed and developing settings. Emerging approaches based on microfluidics and nanotechnology, which have potential to be integrated into POC HIV-1 viral load assays, are also discussed.

Simple filter microchip for rapid separation of plasma and viruses from whole blood

“…In a clinical laboratory setting, plasma separation can simply be performed by centrifugation, whereas it remains a challenge at the POC, especially in resource-constrained settings due to lack of laboratory infrastructure. [18][19][20] Hence, simple, inexpensive, and rapid plasma separation on-chip is urgently needed to facilitate POC diagnosis.…”

Portable microfluidic chip for detection of Escherichia coli in produce and blood

“…13 Although polymerase chain reaction (PCR) has high sensitivity and specificity, 14 the need for a thermal cycler makes it unsuitable for point-of-care (POC) testing. 15 Therein lies the niche for which microfluidic technologies are ideal; they have been employed to develop POC testing devices because of low manufacturing cost, reduced consumption of samples and reagents, and shortened assay time. [15][16][17][18][19][20] However, existing microfluidic devices for bacterial detection, either based on PCR 21 or enzyme-linked immunosorbent assay (ELISA), require multiple sample processing steps prior to detection.…”

“…15 Therein lies the niche for which microfluidic technologies are ideal; they have been employed to develop POC testing devices because of low manufacturing cost, reduced consumption of samples and reagents, and shortened assay time. [15][16][17][18][19][20] However, existing microfluidic devices for bacterial detection, either based on PCR 21 or enzyme-linked immunosorbent assay (ELISA), require multiple sample processing steps prior to detection. 22,23 All of these methods suffer from challenges The sample is sub-cultured into a nutrient-rich agar plate for the identification of the species and to determine the bacterial concentration.…”

Single Real-Time Reverse Transcription-PCR Assay for Detection and Quantification of Genetically Diverse HIV-1, SIVcpz, and SIVgor Strains

“…If HIV quantification assays are rarely present or only in reference laboratories of resource-limited countries, it is mainly due to their high cost which can reach 50 to 100 dollars per sample (i.e., higher than the cost of ART) and their need for specific instruments and trained staff (2). Two cheaper alternatives to classical molecular methods, heat-dissociated HIV-1 p24 antigen enzyme-linked immunosorbent assay (ELISA) (3,4) and the Cavidi ExaVir reverse transcriptase activity assay (5,6), have been proposed but have demonstrated inconclusive results for the first and need further improvement and evaluation for the second (7)(8)(9).…”

“…Two cheaper alternatives to classical molecular methods, heat-dissociated HIV-1 p24 antigen enzyme-linked immunosorbent assay (ELISA) (3,4) and the Cavidi ExaVir reverse transcriptase activity assay (5,6), have been proposed but have demonstrated inconclusive results for the first and need further improvement and evaluation for the second (7)(8)(9). Dipstick and chip technologies are still in development (2,10,11). Therefore, recent "in-house" or generic real-time RT-PCR assays have shown diverse advantages and are relatively inexpensive (the real-time technology is widely used in HIV and other viral infection detections) (12)(13)(14).…”