Tag Archives: Adam R Hall

Nanoscale measurements for osteoarthritis biomarker

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There’s a new technique for measuring hyaluronic acid (HA), which appears to be associated with osteoarthritis. A March 12, 2018 news item on ScienceDaily makes the announcement,

For the first time, scientists at Wake Forest Baptist Medical Center have been able to measure a specific molecule indicative of osteoarthritis and a number of other inflammatory diseases using a newly developed technology.

This preclinical [emphasis mine] study used a solid-state nanopore sensor as a tool for the analysis of hyaluronic acid (HA).

I looked at the abstract for the paper (citation and link follow at end of this post) and found that it has been tested on ‘equine models’. Presumably they mean horses or, more accurately, members of the horse family. The next step is likely to be testing on humans, i.e., clinical trials.

A March 12, 2018 Wake Forest Baptist Medical Center news release (also on EurekAlert), which originated the news item, provides more details,

HA is a naturally occurring molecule that is involved in tissue hydration, inflammation and joint lubrication in the body. The abundance and size distribution of HA in biological fluids is recognized as an indicator of inflammation, leading to osteoarthritis and other chronic inflammatory diseases. It can also serve as an indicator of how far the disease has progressed.

“Our results established a new, quantitative method for the assessment of a significant molecular biomarker that bridges a gap in the conventional technology,” said lead author Adam R. Hall, Ph.D., assistant professor of biomedical engineering at Wake Forest School of Medicine, part of Wake Forest Baptist.

“The sensitivity, speed and small sample requirements of this approach make it attractive as the basis for a powerful analytic tool with distinct advantages over current assessment technologies.”

The most widely used method is gel electrophoresis, which is slow, messy, semi-quantitative, and requires a lot of starting material, Hall said. Other technologies include mass spectrometry and size-exclusion chromatography, which are expensive and limited in range, and multi-angle light scattering, which is non-quantitative and has limited precision.

The study, which is published in the current issue of Nature Communications, was led by Hall and Elaheh Rahbar, Ph.D., of Wake Forest Baptist, and conducted in collaboration with scientists at Cornell University and the University of Oklahoma.

In the study, Hall, Rahbar and their team first employed synthetic HA polymers to validate the measurement approach. They then used the platform to determine the size distribution of as little as 10 nanograms (one-billionth of a gram) of HA extracted from the synovial fluid of a horse model of osteoarthritis.

The measurement approach consists of a microchip with a single hole or pore in it that is a few nanometers wide – about 5,000 times smaller than a human hair. This is small enough that only individual molecules can pass through the opening, and as they do, each can be detected and analyzed. By applying the approach to HA molecules, the researchers were able to determine their size one-by-one. HA size distribution changes over time in osteoarthritis, so this technology could help better assess disease progression, Hall said.

“By using a minimally invasive procedure to extract a tiny amount of fluid – in this case synovial fluid from the knee – we may be able to identify the disease or determine how far it has progressed, which is valuable information for doctors in determining appropriate treatments,” he said.

Hall, Rahbar and their team hope to conduct their next study in humans, and then extend the technology with other diseases where HA and similar molecules play a role, including traumatic injuries and cancer.

Here’s a link to and a citation for the paper,

Label-free analysis of physiological hyaluronan size distribution with a solid-state nanopore sensor by Felipe Rivas, Osama K. Zahid, Heidi L. Reesink, Bridgette T. Peal, Alan J. Nixon, Paul L. DeAngelis, Aleksander Skardal, Elaheh Rahbar, & Adam R. Hall. Nature Communications volume 9, Article number: 1037 (2018) doi:10.1038/s41467-018-03439-x
Published online: 12 March 2018

This paper is open access.

Faster, cheaper, pseudo-organs (also known as organoids)

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There’ve been any number of ‘organoid’ stories recently, here and elsewhere. This one is special due to a quasi extra-cellular matrix (cells have a type of skeletal structure known as an extra-cellular matrix or ECM). From a Sept. 11, 2015 news item on Azonano,

Scientists have developed a new technique that produces a user friendly, low cost, tissue-engineered pseudo-organ. The chip-based model produces a faithful mimic of the in vivo liver inside a scalable fluid-handling device, demonstrating proof of principle for toxicology tests and opening up potential use in drug testing and personalised medicine.

…

The work was done by researchers based at the Wake Forest Institute for Regenerative Medicine and the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences. They created a device architecture within which were a series of 3D liver cell constructs enclosed in a biopolymer that closely mimics the extra-cellular matrix (ECM). Surrounding the printed cells with this ECM – which the body uses to support cells in the liver – makes this model a more realistic model of the cells in vivo.

A Sept. 10, 2015 Institute of Physics (IOP) press release, which originated the news item, provides more details about the technology,

The technique uses photopatterning to produce defined 3D constructs in a microfluidic system to probe the construct quickly. “It’s basically scaled-down pluming” explains Adam Hall, an author on the paper. “This paper describes fairly hefty devices – a few mm – but we’re working to scale this down considerably.”

Collaboration proved to be the key to success; “The challenges were not too significant once Adam and I merged our areas of expertise.” adds Aleksander Skardal, another author on the paper. “With his background in devices and microfabrication, and my background in biomaterials and biofabrication, the two technologies integrated rather well.”

The 3D construct device offers a new tool in the development of drug treatments. At present, 2D testing in vitro doesn’t replicate the activity of the cells, and until now 3D systems have not provided adequate interactions of cells with the ECM, or offered particularly high-throughput testing.

This is where the combination of technologies has proven vital. “3D constructs are less effective if you can’t probe them quickly” continues Hall. “And without some important task, microfluidics are just a fun party trick.”

The researchers were also happy how quickly the techniques fell into place.

“The first time we attempted to perform the in situ photopatterning – it just worked” says Skardal. “Science isn’t always that easy, so we knew we might be onto something.”

“Yes – this was one of those rare occasions where things seemed to fall into place” adds Hall.

The researchers are now working to reduce the size of the system allowing for multiple constructs that could be tested individually. This would open potential usage in drug testing and personalised medicine.

“Imagine being able to put, for example, tumor cells from a patient on a chip and test different drug cocktails on them” they conclude. “You could determine the effectiveness and side effects of different treatments on an individual basis without endangering the patient.”

Here’s a link to and a citation for the paper,

In situ patterned micro 3D liver constructs for parallel toxicology testing in a fluidic device by Aleksander Skardal, Mahesh Devarasetty, Shay Soker, and Adam R Hall. Biofabrication, Volume 7, Number 3 DOI: 10.1088/1758-5090/7/3/032001 Published 11 September 2015

© 2015 IOP Publishing Ltd

This is an open access paper.