Emerging technologies for point-of-care CD4 T-lymphocyte counting

Abstract

A CD4 T-lymphocyte count determines eligibility for antiretroviral therapy (ART) with patients recently diagnosed with HIV and also monitors the efficacy of ART treatment thereafter. ART slows the progression of HIV to AIDS. In the developing world, CD4 tests are often performed in centralized laboratories, typically in urban areas. The expansion of ART programs into rural areas has created a need for rapid CD4 counting as logistical barriers can delay the timely dissemination of test results and affect patient care through delay in intervention or loss of follow-up care. CD4 measurement at the point-of-care (POC) in rural areas could help facilitating ART and monitoring of treatment. This review highlights recent technology developments with applications towards determining CD4 counts at the POC.

Handheld high-throughput plasmonic biosensor using computational on-chip imaging

“…Similarly, various point-of-care diagnostic devices have been developed and among them optical imaging and sensing techniques are highly advantageous as they can provide real-time, highresolution and highly sensitive quantitative information, potentially assisting rapid and accurate diagnosis. [30][31][32][33][34][35][36][37][38][39][40] To date, a number of optical techniques have been proposed for point-of-care diagnostics such as in vitro optical devices, [41][42][43][44][45][46][47][48][49][50][51][52][53] including portable optical imaging systems, optical microscopes integrated to cell phones or in vivo optical devices, [54][55][56][57][58][59][60][61][62][63] involving confocal microscopy, microendoscopy and optical coherence tomography techniques. Among these approaches, lens-free computational on-chip imaging 64 has been an emerging technique that can eliminate the need for bulky and costly optical components while also preserving (or even enhancing in certain cases) the image resolution, field of view and sensitivity.…”

Micro- and Nanotechnology for HIV/AIDS Diagnostics in Resource-Limited Settings

“…A semiquantitative immunochromatographic strip (ICS) being developed by The Burnet Institute compares the intensity of gold particles that are specifically attached to CD4+ T cells at a CD4 capture strip to a reference strip which has a similar intensity to a known concentration of CD4+ T cells [126]. Zyomyx has developed a device that uses the sedimentation of high-density CD4 antibody-conjugated beads to estimate the concentration of CD4+ T cells from whole blood samples [126], [127]. These beads specifically attach to the CD4+ T cells and are sedimented with the help of a manually powered centrifuge.…”

Centrifugo-Magnetophoretic Purification of CD4+ Cells from Whole Blood Toward Future HIV/AIDS Point-of-Care Applications

“…HIV diagnostic devices employing LOC strategies have seen medical and commercial success since 2009 and have been extensively reviewed recently. 8,9 A number of research groups have developed LOC techniques and devices enabling the purification of specific phenotypes from biological backgrounds. Many of these devices have made use of paramagnetic beads to bind cells in a mobile phase and subsequently relocate them to detectors or areas on a chip where they can be manually enumerated.…”