Madison, Wisc.-based nanotech shop Platypus Technologies plans to launch its first cell-based assay — the Oris cell migration assay, which it claims is easier to use and more reproducible than current methods — within the week, a company official told CBA News this week.
Development of the assay was primarily funded by a $450,000 Phase I Small Business Innovation Research grant that the National Institutes of General Medical Sciences awarded last September.
The primary advantage of the Platypus product is its ease of use and reproducibility compared to current cell migration assays, said Jeff Williams, the president and CEO of Platypus. He added that the main challenge in typical cell migratory assays is the high degree of variability in the results, and researchers currently have to do many replications in order to get data that they feel comfortable with.
“We feel that the simplicity of our approach has allowed the Platypus assay, at least in our hands and the hands of our beta testers, to give very reproducible results,” Williams said.
The assay comes in a 96-well plate format. Inserts made of medical-grade silicon are placed into the center of each well to create a restricted, 2-millimeter diameter area. Researchers can then seed the outer region of the well, while the insert prevents the cells from seeding in the center.
Once the cells attach to the sides of the well, the insert is removed and the cells migrate into the center where they can be quantified using a fluorescence plate reader or viewed directly through a microscope using fluorometric or colorimetric labels.
Williams said the assay can use any fluorescent dye, but that the company is currently using Invitrogen’s Celltracker Green CMFDA and BD Biosciences’ Calsein AM, although it has tried several others.
Initially, the assay will be launched in the US only and distributed directly by Platypus, said Williams. The company plans to have foreign distributors in place by the end of the year.
He said that the most appropriate applications for the assay will probably be in the areas of oncology and wound healing. The assay mimics cancer metastases and could help researchers better understand why, for example, prostate cancer cells often metastasize to the bone marrow and breast cancer cells tend to metastasize to the liver and lungs.
Cell migration is also important in angiogenesis, cardiac research, and a host of other functions, Williams said. “Understanding how and why cells move is crucial to understanding basic bodily mechanisms, and is also important for the development of drugs to either increase or decrease this movement,” he said.
Platypus’ initial market focus will be on laboratories at academic and research institutions, said Williams, though he said that company has also received interest from pharmaceutical companies.
He said that the company plans to work with pharmaceutical customers to see if any changes are necessary to make the assay fit their needs.
Williams said that the beta-testing sites that Platypus has been working with are Harvard Medical School, the University of Vermont, Memorial Sloan-Kettering Cancer Center, the University of Connecticut, and the University of Wisconsin.
Williams reported that beta-testing has gone very well, and that the feedback from these sites been very positive.
“We really have not made any changes to the product, although we have discovered that we need to provide more detail in the protocol,” he said.
For example, the company must help its customers understand that when they seed the plate, they must be certain to get a homogenous layer of cells. Williams pointed out that the cells tend to collect on one side of the well or the other if the researcher does not give the well a gentle tap.
The company has also found that it’s important to use a cell-staining method that gives a very homogeneous stain throughout, he said.
Although a number of “home-brew” assays for studying two-dimensional cell migration are available, Williams said that Platypus sees the BD Biosciences BioCoat and Falcon FluoroBlok family of products as its closest competitors.
However, Marshall Kosovsky, technical support manager for BD Biosciences Discovery Labware said that the company’s cell migration assay products are quite different from those of Platypus.
BD’s cell culture inserts have a porous membrane that, when fitted into a well in a cell culture plate, essentially forms a two-compartment system, said Kosovsky. This two-compartment system forms a “dynamic environment” where a chemical gradient can easily be established, he said.
Kosovsky explained that the Platypus system uses one compartment only and does not incorporate a porous membrane. The purpose of the Platypus insert is to block a portion of the well floor, which prevents cells from seeding in that region at the beginning of the assay. After the insert is removed, the cells can migrate two-dimensionally into the space that was created by the insert
With BD cell culture inserts, a chemical gradient can be established because the porous membrane effectively divides the culture environment into two compartments, Kosovsky said. A gradient can form across the membrane by initially adding a chemical such as a growth factor to one compartment only. Over time, the chemical will diffuse across the membrane into the second compartment to form the gradient.
“Understanding how and why cells move is crucial to understanding basic bodily mechanisms, and is also important for the development of drugs to either increase or decrease this movement.”
Kosovsky said that the BD Falcon and BD BioCoat inserts that incorporate the FluoroBlok microporous membrane are especially useful for cell migration assays that are analyzed using a bottom-reading fluorescence plate reader because the reader will only detect fluorescently-labeled cells that have migrated to the underside of the FluoroBlok membrane, which blocks fluorescent light between 490 nm and 700 nm. Any fluorescently-labeled cells that remain on top of the membrane will not be detected by the plate reader.
The BD FluoroBlok membrane gives researchers an accurate measure of the cells that have migrated in response to a chemical gradient, said Kosovsky. Those that have not migrated are excluded from the results.
Platypus was founded in 2000 by three professors at the University of Wisconsin — Nicolas Abbott, Christopher Murphy, and Barbara Israel — with the goal of developing assay products in the analytical and life sciences.
The company’s moniker arises from the ability of the duck-billed platypus to detect specific prey in complex and muddied environments using a surface within its bill that is studded with chemical receptors. Like its namesake, Platypus Technologies develops devices to rapidly identify a wide range of target molecules present in complex samples through specific interactions with nanostructured surfaces, according to its web site.
Platypus currently has 21 employees and is housed in an 8,000-square-foot facility. Williams said that the company is looking to hire a chief technology officer and a business development manager and is currently reviewing resumes for those spots.
In addition, Platypus will probably expand its sales and marketing staff by at least three or four people at the product manager level early next year, said Williams.
Platypus has currently received about $3 million in angel funding. Williams declined to further discuss financing issues, however.
The company plans to quickly follow the launch of its cell migration assay with follow-on products such as coated plates, including collagen- and fibronectin-coated plates, said Williams. Platypus is also developing an invasion assay.
Williams said the company hopes to launch some of the coated plates before the end of the year.