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    Device Technologies and Biomedical Robotics

    (J-387) Development of a Rapid HIV RNA Magnetic Bead Extraction Method from Whole Blood for Smartphone-Based Detection

    Saturday, October 14, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row J - Poster # 387

      Presenting Author(s)

    • WN

      Winston Ngo (he/him/his)

      Undergraduate Research Assistant
      Purdue University
      West Lafayette, Indiana, United States

      • Co-Author(s)

    • Mia T. Nair

      Undergraduate Research Assistant
      Purdue University
      West Lafayette, Indiana, United States

    • Emeka Nwanochie

      Research Assistant (PhD Candidate)
      Purdue University
      WEST LAFAYETTE, Indiana, United States

      • Primary Investigator(s)

    • JL

      Jacqueline C. Linnes, PhD (she/her/hers)

      Marta E. Gross Associate Professor
      Purdue University
      West Lafayette, Indiana, United States

    Introduction:: INTRODUCTION
    The HIV/AIDS global epidemic continues to be a major problem, especially in the Sub-Saharan African region     1. In 2022, an estimated 39.0 million people were living with HIV globally 2.  Antiretroviral therapy (ART) is currently being used as an effective HIV treatment option to prevent the onset of AIDS via the reduction of patients’ viral load to undetectable levels. Furthermore, an undetectable viral load significantly reduces the risk of HIV transmission. Despite the availability of ART, 24% of those living with HIV in 2022 have yet to obtain treatment 1. Current viral load monitoring requires multiple visits to centralized testing facilities and presents a significant barrier to HIV treatment. Thus, there exists a need for the development of an inexpensive self-test platform for rapid viral load monitoring with the goal of keeping patients in continued care. A smartphone-based, point-of-care HIV test in blood has already been developed, but sample preparation will reduce the limit of detection for practical implementation. Purified HIV RNA will be used in downstream on-chip reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) and detected by the existing smartphone-based HIV test. Presented here is a method utilizing magnetic beads and air surface tension valves to effectively purify HIV RNA from whole blood.

    Materials and Methods:: MATERIALS AND METHODS
    Magnetic beads, lysis buffer, wash, and elution reagents from commercial kits (#    AM1939, MagMax Viral RNA Isolation Kit) are used within the device. Reagents are pre-packaged within 1/16 in. ID silicone tubing, and air surface tension valves separate each reagent. Two cylindrical magnets (#D48DIA, K&J Magnetics, Pipersville, PA) draw the magnetic beads through the tubing starting in the lysis/binding solution, through two wash steps, and ending in an elution buffer. The tube-extracted RNA is then amplified via an RT-LAMP reaction.

    Results, Conclusions, and Discussions::

    RESULTS AND DISCUSSION


    HIV RNA was successfully purified from HIV-spiked human whole blood samples with a limit of detection from RT-LAMP of 1000 virion copies/uL. Mineral oil valves were considered as an alternative to air valves, but the advantages in reproducibility and reagent loading simplicity made air valves a more feasible choice. Additional modifications can be made to the device to improve usability and integrate all sample preparation steps within the tubing. Further changes to the extraction process or sample matrix may be required to improve the sensitivity.




    CONCLUSION


    We have demonstrated a rapid magnetic bead HIV RNA extraction that enables RT-LAMP at a limit of detection of 1000 virons/uL in a simple-to-use format for point-of-care implementation. Comparison to other extraction methods in terms of feasibility for integration into smartphone PD detection and quantification using PCR will both be investigated as future work. Additionally, further work will be carried out to ensure the device is ready for field trials in Kenya.



    Acknowledgements (Optional): :

    References (Optional): :

    REFERENCES




    1. Global HIV & AIDS statistics - fact sheet. UNAIDS. (n.d.). https://www.unaids.org/en/resources/fact-sheet 




    2. World Health Organization. (n.d.-a). HIV and AIDS. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/hiv-aids