Graphene Biosensors for the Early Detection of RNA Viruses Inayat Bajwa

Format:

Book

Thesis/Dissertation

Author/Creator:

Bajwa, Inayat, author.

Contributor:

University of Pennsylvania. Bioengineering., degree granting institution.

Language:

English

Subjects (All):

0202.

0652.

0786.

Local Subjects:

0202.

0652.

0786.

Physical Description:

1 electronic resource (119 pages)

Contained In:

Dissertations Abstracts International 87-07B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2025

Language Note:

English

Summary:

RNA viruses pose a great pandemic risk due to their high mutation and substitution rates, creating an urgent need for inexpensive, rapid, and reliable nucleic acid tests that enable early detection at point-of-care or over-the-counter settings with sensitivity and specificity comparable to the gold standard RT-qPCR tests. This dissertation presents graphene field-effect transistors (GFETs) as candidates for the rapid, ultrasensitive, label-free and amplification-free detection of RNA genomes at the few-copy level. GFETs are customized to detect two RNA viruses, HIV-1 type B and SARS-CoV-2, through functionalization of the graphene channels with DNA probes specific to highly conserved regions of the viral RNA, ensuring high target specificity and minimal response to non-specific viral RNA sequences. Scalable fabrication methods produce 572 GFETs in a single batch, arranged into arrays of 52 devices each. GFET arrays enable multiplexed detection, achieving rapid response times of 30 - 60 minutes and a low limit of detection (LOD) of 0.1 aM (~ 60 copies/ml) for HIV-1 and SARS-CoV-2 in RNase-free water, as well as for HIV-1 in Qiazol, a lysis reagent. GFETs demonstrate sensitivity comparable to RT-qPCR (LOD: 10 -100 copies/ml) while offering a significantly faster response time than RT-qPCR tests, which typically require 2 - 3 hours. Portability is achieved by transitioning from a back-gated GFET architecture with a thick low-k dielectric film to a buried-gate architecture with a thin high-k dielectric film, increasing the gate capacitance from 1.2 x 10-8 F/m2 to 3.27 x 10-7 F/m2, and reducing the gate voltage from ± 130V to ± 5 - 6 V. Lower operating voltage enables the successful integration of GFETs with microelectronics to assemble a portable sensing platform. GFET arrays for the portable sensor are redesigned to increase array density per wafer, improving scalability by producing 34.27% more GFETs per fabrication batch. These results establish GFETs as a strong candidate for advancing point-of-care and over-the-counter diagnostics for early detection of RNA viruses

Notes:

Advisors: Johnson, A. T. Charlie Committee members: Ko, Jina; Drndić, Marija; Jiang, Yuanwen

Source: Dissertations Abstracts International, Volume: 87-07, Section: B.

Ph.D. University of Pennsylvania 2025

Vendor supplied data

Local Notes:

School code: 0175

ISBN:

9798276001982

Access Restriction:

Restricted for use by site license