DNA-Engineered Micromotors Enable Cellphone Detection of HIV

By Will Boggs MD

November 20, 2018

NEW YORK (Reuters Health) - A novel cellphone-based system uses DNA-engineered micromotors powered by metal nanoparticles to detect HIV in blood with high sensitivity and specificity, researchers report.

"We demonstrated the feasibility of integrating cellphones, nano-, and micro-technology for accurate HIV detection," Dr. Hadi Shafiee from Brigham and Women's Hospital and Harvard Medical School, in Boston, told Reuters Health by email. "A fully automated version of our system can be used for HIV-treatment monitoring at the point of care in resource-limited settings or at a clinic to get the important HIV testing results on-site."

Self-propelling nanoparticle motor systems have been reported for DNA and protein sensing and diagnosis of different pathogens and diseases.

Dr. Shafiee's team developed a cellphone-based assay for HIV-1 molecular detection that senses the change in motion of DNA-engineered micromotors powered by metal nanoparticles.

Their "CALM" system detected HIV in serum samples spiked with HIV-1 and in patient plasma samples with 94.6% sensitivity and 99.1% specificity, for an overall accuracy (AUC) of 98.4%, using real-time PCR as the standard.

Similarly, the system correctly classified 100% of spiked samples as positive and 90% of samples as negative, the team reports in Nature Communications, online November 9.

The velocity of the micromotors decreased in the presence of HIV-1, but the velocity was not altered in the presence of other viruses.

The CALM system was also 100% concordant with a quantitative real-time PCR assay that targets a highly conserved region of integrase in the HIV-1 pol gene in classifying patient samples as positive (1,000 or more virus particles/mL) or negative (<1000 virus particles/mL).

"HIV/AIDS is still a major clinical worldwide problem with more than 36 million HIV-infected individuals globally," Dr. Shafiee said. "Unfortunately, more than 70% of these individuals live in the developing countries, particularly African countries where we have limited laboratory infrastructure and trained staff."

"One of the main challenges in HIV management in such regions is identifying the infected individuals and keeping them on an effective antiretroviral therapy (ART)," he said. "To do that, we need low-cost, rapid, and portable diagnostics that can be deployed in such poor settings, as the currently available diagnostic tools in the developed world are lab-based, complex, time-consuming, and expensive."

"In this work, we showed the ability of a low-cost (<$5 material costs) cellphone system for HIV detection in complex biological samples," Dr. Shafiee said. "A fully automated version of our developed technology can be used for ART monitoring on-site that can be operated by a health worker or physician without the need for sophisticated, expensive, and lab-based systems for HIV viral load testing."

"Further testing using the standard laboratory-based methods will be needed to confirm positive results generated by the presented cellphone system before initiating any treatment," the researchers note. "The proposed system has a great potential for broad applications in infectious diseases control and management."

SOURCE: https://bit.ly/2qNbbjo

Nat Commun 2018.