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GBS Developing Organic Thin-Film Transistor Tech to Detect SARS-CoV-2 Antibodies, Monitor Glucose


NEW YORK ─ Sydney-based point-of-care diagnostic testing company GBS is developing a disposable biosensor platform to enable testing at the point of care for a range of medical conditions including SARS-CoV-2 past infection and diabetes.

The biosensor platform, which leverages organic thin-film transistor technology originally developed for solar panels, has the potential to enable high-volume test manufacturing at low cost, Daniel Pointing, biosensor development manager at GBS, said in an interview.

The biosensors use inexpensive electronic inks to conduct electric current and transmit diagnostic testing signals in response to the presence of a range of disease analytes, Pointing said.

Later this year, GBS — a portfolio company of Australian private equity company iQ Group Global — expects to launch its first assay, which combines its organic thin-film transistor technology with an electrochemical biosensor technology, called eRapid, being developed by Harvard University's Wyss Institute. The technologies are being integrated with the aim of producing a highly sensitive and specific multiplex antibody test for SARS-CoV-2 that operates from blood samples.

GBS will seek US Food and Drug Administration Emergency Use Authorization for the antibody test and aims to collaborate with US distributors to begin marketing later this year. The firm will target clinicians seeking to detect specific antibodies against SARS-CoV-2 in patients and to evaluate immune response after infection or vaccination, Pointing said.

Before it began working with the Wyss Institute, GBS had been developing its biosensor technology for a disposable assay for diabetes patients that provides a measurement of glucose concentration upon contact with saliva and provides results through a smartphone. The company aims to market the glucose biosensor as an alternative to "painful, invasive, and inconvenient" fingerstick testing, Pointing said, adding that it expects to apply to the FDA for de novo classification of the test early next year.

The firm further intends to seek regulatory approvals to market the glucose test in Europe and the Asia Pacific region, and it will eventually seek reimbursement on the back of future studies and anticipated regulatory clearances, Pointing added.

In February, GBS announced a research agreement with Johns Hopkins Bloomberg School of Public Health to accelerate the development of its saliva-based diagnostic tests. The program aims to support the development of its glucose test and a saliva-based version of the SARS-CoV-2 antibody test it is developing with the Wyss.

Pointing said that with slight modifications the organic thin-film transistor technology is amenable to a number of different medical indications including in oncology, immunology, and endocrinology. "Our aim is to bring these two initial tests to market and take them through regulatory pathways as we also set the stage for developing future tests to address these other conditions," he added.

Its use of reel-to-reel fabrication, which leverages inkjets to print thousands of biosensors per run on flexible plastic sheets, sets it apart from other diagnostic test manufacturing processes, Pointing said. For manufacturing, the firm uses the Australian National Fabrication Facility, which is based at the University of Newcastle in New South Wales, where the organic thin-film transistor technology was invented.

Research into the technology underpinning GBS' biosensing platform began in 1997 when a group led by Paul Dastoor, founder and director of the Center for Organic Electronics at the University of Newcastle, began adapting technology it was using for solar cells to develop biosensors. The group published a study in 2014 in the journal Electronics, describing the development of an organic thin-film transistor technology for biosensors. A second study in 2015, published in Applied Physics Letters, described the development of the transistors for glucose detection and use of inkjet-printing to fabricate the enzyme-based recognition element.

IQ Group Global acquired the organic thin-film transistor technology through a license agreement with the University of Newcastle in 2016, and GBS subsequently announced an expansion of R&D to begin developing its biosensor for medical indications other than glucose monitoring. In 2019, Pointing and his colleagues contacted the Wyss Institute after reading a study in Nature Nanotechnology about the Wyss' development of eRapid electrochemical biosensing technology. "We noticed that eRapid technology consists of a printable gel that generates electrons in response to an analyte, which is similar to the technology we are using in the saliva-based glucose biosensor project," Pointing said.

For SARS-CoV-2 antibody testing, GBS replaced a glucose oxidase layer that enables the detection of glucose concentrations in its diabetes test with an eRapid biosensor layer. "The reaction between target biomarkers and eRapid's antibody recognition elements generates electrons that we measure using the thin-film transistors," Pointing said.

GBS and the Wyss Institute have launched a validation study for the antibody test using clinical plasma samples from SARS-CoV-2 patients. Brigham and Women’s Hospital, Massachusetts General Hospital, and Beth Israel Deaconess Hospital are providing serum and saliva samples including at least 35 positive samples from patients with past SARS-CoV-2 infection and 35 negative samples.

In the biosensor, eRapid's surface antigens detect antibodies against the virus' nucleocapsid and spike proteins, and the receptor binding domain, said Pawan Jolly, a lead developer of eRapid at the Wyss Institute.

The antigens are embedded in a surface layer that enables highly sensitive and specific detection of targets in complex matrices, including plasma and whole blood, without the need for sample preparation, he said.

The study investigators are looking to establish sensitivity and specificity data for the biosensor, Jolly said, adding that with eRapid technology alone, the Wyss has obtained single-digit picogram-per-milliliter sensitivity with unprocessed samples.

The developers anticipate that combining the Wyss and GBS technologies will lead to a test that consumers can use to quickly measure levels of specific SARS-CoV-2 antibodies, Jolly added. Further, GBS' collaboration with Johns Hopkins could lead to a multiplexed saliva-based platform to detect SARS-CoV-2 antibodies, and enable broader use of the antibody test because saliva is a less invasive sample than blood, he said.

Whether a large market for SARS-CoV-2 antibody testing will emerge remains to be seen. "People are still figuring out the best use case for antibody testing, but we believe it will be useful for monitoring patients who are receiving COVID-19 treatments and have received vaccines, and for new vaccines development," Jolly said.

Like GBS, the Wyss Institute is developing its testing technology for a few medical indications. In April, Jolly and his colleagues published a study in Advanced Functional Materials about the application of eRapid's antifouling conductive coating to enable the sensitive and selective multiplexed detection of sepsis biomarkers in whole blood. In November 2019, the group published a study in Nature Nanotechnology to demonstrate the potential of eRapid for the detection of the inflammatory cytokine IL-6 and hormones in unprocessed human plasma.

The biosensor validation study with GBS represents a milestone for the Wyss, which "shows that eRapid is versatile and can be easily repurposed for many indications," which further demonstrates its compatibility with the Australian company's biosensor technology, Jolly said.

GBS is not disclosing the anticipated price of its biosensor tests. However, as an indication of biosensor component costs, the Wyss Institute researchers reported in a recent study that the nanocomposite reagents costs for eRapid were $.08 per test and could further decrease with manufacturing at scale.