KS-Detect – Validation of Solar Thermal PCR for the Diagnosis of Kaposi’s Sarcoma Using Pseudo-Biopsy Samples

Abstract

Resource-limited settings present unique engineering challenges for medical diagnostics. Diagnosis is often needed for those unable to reach central healthcare systems, making portability and independence from traditional energy infrastructure essential device parameters. In 2014, our group presented a microfluidic device that performed a solar-powered variant of the polymerase chain reaction, which we called solar thermal PCR. In this work, we expand on our previous effort by presenting an integrated, portable, solar thermal PCR system targeted towards the diagnosis of Kaposi’s sarcoma. We call this system KS-Detect, and we now report the system’s performance as a diagnostic tool using pseudo-biopsy samples made from varying concentrations of human lymphoma cell lines positive for the KS herpesvirus (KSHV). KS-Detect achieved 83% sensitivity and 70% specificity at high (≥10%) KSHV+ cell concentrations when diagnosing pseudo-biopsy samples by smartphone image. Using histology, we confirm that our prepared pseudo-biopsies contain similar KSHV+ cell concentrations as human biopsies positive for KS. Through our testing of samples derived from human cell lines, we validate KS-Detect as a viable, portable KS diagnostic tool, and we identify critical engineering considerations for future solar-thermal PCR devices.

Diagnosis and Treatment of Kaposi Sarcoma

“…In such cases, LANA-stained sections should be carefully re-assessed for subtle granular staining in KS cell nuclei [76]. PCR has been shown to reliably detect HHV-8 in KS lesions even in the absence of LANA expression [77, 78]. However, recent studies highlighted potential contamination of KS biopsies with subsequent false positive PCR results for HHV-8 [79].…”

The Role of Affordable, Point-of-Care Technologies for Cancer Care in Low- and Middle-Income Countries: A Review and Commentary

“…The portable system amplifies target DNA by cycling samples through three temperature zones and performs subsequent analysis of amplified DNA at the POC [74] . Reduced power consumption allows an iPhone battery or solar energy to provide necessary energy for 70+ hours of use, making the device a novel solution for PCR in settings with limited access to reliable power [74] , [98] . The device case includes all material to conduct sample preparation and analysis, and it can be carried in one hand [98] .…”

“…Reduced power consumption allows an iPhone battery or solar energy to provide necessary energy for 70+ hours of use, making the device a novel solution for PCR in settings with limited access to reliable power [74] , [98] . The device case includes all material to conduct sample preparation and analysis, and it can be carried in one hand [98] . While the device is currently targeted to detect Kaposi’s sarcoma herpesvirus, use of primers for other oncogenic viruses could make the system useful for POC diagnosis across a range of molecular targets [98] .…”

“…The device case includes all material to conduct sample preparation and analysis, and it can be carried in one hand [98] . While the device is currently targeted to detect Kaposi’s sarcoma herpesvirus, use of primers for other oncogenic viruses could make the system useful for POC diagnosis across a range of molecular targets [98] .

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Improving the Sensitivity and Functionality of Mobile Webcam-Based Fluorescence Detectors for Point-of-Care Diagnostics in Global Health

“…A smartphone with a CMOS detector has been used as a portable ELISA detector [ 76 ], utilizing the integrated phone camera as a spectrometer for detection of IL-6, a protein used diagnostically for several types of cancer, as well as the Ara h 1 protein, one of the principle peanut allergens. More recently, a portable solar thermal PCR was developed that analyzes fluorescence levels imaged by a smartphone or tablet [ 123 ] and was used for the diagnosis of Kaposi’s sarcoma [ 124 ].…”