Browsing by Author "Rodriguez-Mateos, Pablo"

Now showing 1 - 2 of 2
  • Thumbnail Image
    PublicationOpen Access
    An integrated lab-on-a-chip device for RNA extraction, amplification and CRISPR-Cas12a-assisteddetection for COVID-19 screening in resource-limited settings
    (MedRXiv, 2022-01-06) Ngamsom, Bongkot; Iles, Alexander; Kamita, Moses; Kimani, Racheal; Rodriguez-Mateos, Pablo; Mungai, Mary; Dyer,Charlotte; Walter, Cheryl; Pamme, Nicole; Gitaka, Jesse
    n response to the ongoing COVID-19 pandemic and disparities of vaccination coverage in low-and middle-incomecountries, it is vital to adopt a widespread testing and screening programme, combined with contact tracing, to monitor and effectively control the infection dispersion in areas where medical resources are limited.This work presents a lab-on-a-chip platform, namely“IFAST-CRISPR”, as an affordable, rapid and high-precision molecular diagnostic means for SARS-CoV-2 detection. The herein proposed “sample-to-answer”platform integratesRNA extraction, amplification and CRISPR-Cas-based detection with lateral flow readout in one device. The microscale dimensions of the device containing immiscible liquids, coupled with the use of silica paramagnetic beads and GuHCl, streamline sample preparation, including RNA concentration, extraction and purification, in15 min with minimal hands-on steps. By combining RT-LAMP with CRISPR-Cas12 assays targeting the nucleoprotein (N) gene, visual identification of ≥470 copies mL-1genomic SARS-CoV-2 sampleswas achieved in 45 min, with no cross-reactivity towards HCoV-OC43 nor H1N1. On-chip assays showed the ability to isolate and detect SARS-CoV-2 from 1,000 genome copies mL-1of replication-deficient viral particles in 1 h. This simple, affordable and integrated platform demonstrated a visual, faster, and yet specificity and sensitivity-comparable alternative to the costly gold-standard RT-PCR assay, requiring only a simple heating source. Further investigations on multiplexing and direct interfacing of the accessible Swan-brand cigarette filter for saliva sample collectioncould providea complete work flow for COVID-19 diagnostics from saliva samples suitable for low-resource settings.
  • Thumbnail Image
    PublicationOpen Access
    Integrated microscale immiscible phase extraction and isothermal amplification for colorimetric detection of Neisseria gonorrhoeae
    (SPRINGER LINK, 2023-05-18) Pamme, Nicole; Rodriguez-Mateos, Pablo; Ngamsom, Bongkot; Ameyo, Daglus; Wakaba, Patrick; Shiluli, Clement; Iles,Alexander; Gitaka, Jesse
    Gonorrhea is the second most common sexually transmitted infection (STI) with around 87 million cases worldwide estimated in 2016 by the World Health Organization. With over half of the cases being asymptomatic, potential life-threatening complications and increasing numbers of drug-resistant strains, routine monitoring of prevalence and incidence of infections are key preventive measures. Whilst gold standard qPCR tests have excellent accuracy, they are neither affordable nor accessible in low-resource settings. In this study, we developed a lab-on-a-chip platform based on microscale immiscible filtration to extract, concentrate and purify Neisseria gonorrhoeae DNA with an integrated detection assay based on colorimetric isothermal amplification. The platform was capable of detecting as low as 500 copies/mL from spiked synthetic urine and showed no cross-reactivity when challenged with DNAs from other common STIs. The credit card–size device allows DNA extraction and purification without power or centrifuges, and the detection reaction only needs a low-tech block heater, providing a straightforward and visual positive/negative result within 1 h. These advantages offer great potential for accurate, affordable and accessible monitoring of gonorrhea infection in resource-poor settings.