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Linear Diagnostics Developing Microfluidic Cartridge to Detect Bacteria, Antibiotic Resistance


NEW YORK (GenomeWeb) – Linear Diagnostics, a recent spinout of the University of Birmingham in the UK, is developing a microfluidic cartridge-based platform to detect multi-drug-resistant bacteria in hospitals.  

Founded in 2011 as part of a joint venture between Abingdon Health the University of Birmingham, Linear Dx aims to commercialize bio-nanoparticle optical detection technology developed by Matthew Hicks, a cofounder and chief technical officer of the company, and Tim Dafforn, a professor at the University of Birmingham and a cofounder and director of the company. Although the firm initially focused on agricultural applications, the team saw that its technology could be used for medical applications.

Hicks explained in an interview and via email that Linear Diagnostics' technology is based on the arrangement of long, thin nanometer-sized molecules in a microfluidic chamber inside the company's test cartridge,which is self-contained, sterile, and holds all the reagents needed to perform a test. Using a handheld external optical reader, researchers detect the molecules' alignment in the chamber by shining polarized light from different angles into the cartridge.

Researchers can modify the molecules with detection probes that bind to targets in solution. If bacteria are present in the sample, the  probes bind to various bacterial targets, changing the alignment of the attached molecules in the microfluidic flow.

The attached probes can be antibodies that can recognize specific bacterial cell surface markers, for instance, or short bits of DNA including genetic sequences that recognize specific bacterial transcripts or genes that code for antibiotic resistance.

According to the company's website, the cartridge is capable of analyzing multiple biomarkers simultaneously. However, Hicks noted that the company is initially focusing on smaller tests with just a few targets.

"When we first started, we thought we should look at a range of different antibiotic resistance genes," he said. "Primary care [clinicians] however, wanted the answer to two questions: Are there bacteria present above a certain threshold in the sample, and is there evidence for antibiotic resistance to what we normally prescribe?"  

Linear Dx's tests can be used with urine and whole blood samples, since they do not require previous sample preparation, although Hicks emphasized that his firm will initially focus on urinary tract infections (UTIs).   

According to Hicks, Linear Dx's platform is currently in the alpha development stage, with an estimated product release in early 2019.

Hicks said that the company will use various sub-contracting partners for the external reader. "But since we're in early developmental phase, we're still working with industrial design companies," he added.

Hicks estimates the  to run one of Linear Dx's tests on its platform will be around £15 (US $20). He emphasized that the firm will "supply the reader at either low or zero cost, with a contract for a certain number of cartridges," establishing "a consumable-based business model."

Hicks explained that while technology such as easy, rapid dipstick tests can provide an indication of bacterial presence, they lack the information on antibiotic resistance that Linear Dx's technology can provide.

Many companies and academic groups are developing microfluidic-based approaches to quickly and inexpensively detect bacterial infections and drug resistance.

However, "other molecular binding techniques need multiple processing steps like washing," said Hicks. "In contrast, our platform is a single-step process, and can be adapted to a wide range of other applications in the future, including STIs and tropical diseases."

Supported by the UK's National Health Service, Linear Dx will begin initial trials for the test at hospitals and general practice surgeries as a detector for antimicrobial-resistant UTIs in 2018. These first trials will involve validating the firm's technology against current gold standard procedures.

Hick said that Linear Dx will initially concentrate on the infectious disease detection market, where the firm has developed a growth strategy for the US, Europe, and Southeast Asia.

While the firm's technology involves a simple, single channel with an optical detector, Hicks admits that his team could develop an instrument with higher specificity. An improved specificity however, he said, will increase the product's cost to the end user.

"The reagents that we have developed (and form the core of our IP) enable us to use relatively low-cost hardware to give sufficient performance for the assays that we are developing," he added.  

Linear Dx has raised around £1million of funding through convertible loans since it spun out of the University of Birmingham in 2011. In addition to continual support from the University of Birmingham, Hicks said that Linear Dx will initiate a Series A funding round of £2 million in early 2018.

Linear Dx has been issued patents for the technology underlying its microfluidic cartridges. The company has also filed an application to compete for the Longitude Prize, a £10 million prize fund developed by Nesta, the UK's innovation foundation. That prize will go to a competitor that can develop a diagnostic test to help solve the problem of antibiotic resistance. Entries for the prize have to meet certain criteria for affordability, accuracy, speed, and ease of use at the point of care.