Bioassays & Potency Testing

iFyber specializes in evaluating the effects of new biomaterials, medical devices, and investigational compounds on mammalian biological systems. We are focused on implementing high throughput, repeatable, relevant, and quantitative in vitro assays that provide clients with robust data from which to plan future product development and verification efforts.

Medical technologies employ a diverse range of functional materials, from synthetic polymers to recellularized ECM scaffolds. This diversity can lead to variable chemical and biological interactions occurring at the cell or tissue interface. Whether you are looking to transfer or optimize an existing assay for use with your technology or develop one from scratch, our cross-functional expertise in cell biology and interfacial chemistry ensures a swift path to completed assay development and reliable, actionable results.

iFyber offers a variety of standardized and custom functional bioassays for evaluating the effects of a technology on biological responses at the cellular and tissue levels, including:

  • In vitro biocompatibility testing
  • Cell attachment assays
  • Cell viability and growth assays
  • Cytotoxicity assays
  • Cytokine analysis
  • Morphological measurements of neuronal growth
  • Tissue barrier function testing
  • Cell-based potency assays
  • Protease activity
  • Protein analysis
  • Histology and IHC
  • Flow Cytometry/Fluorescence-activated cell sorting (FACS)

In addition to custom testing solutions, iFyber offers GLP-compliant testing services. Contact our scientists to design a cell- or tissue-based bioassay for your technology.

MTT ASSAY
ISO 10993-5 BIOLOGICAL EVALUATION OF MEDICAL DEVICES—TESTS FOR IN VITRO CYTOTOXICITY

WHAT IS IT?
The MTT assay provides a quantitative assessment of cell proliferation by measuring the activity of mitochondrial enzymes that reduce the tetrazolium salt, MTT, to formazan crystals that are solubilized with acidified isopropyl alcohol. The resulting purple solution is quantified spectrophotometrically at 570 nm. Standard intra-assay controls include vehicle-only (usually cell media) and a relevant mammalian cell toxin to demonstrate appropriate test system response.

WHY USE IT?
MTT is widely regarded as the go-to assay for in vitro cytotoxicity testing and is used regularly in industrial and academic R&D laboratories. The MTT assay has been demonstrated to be a relevant predictor of in vivo biocompatibility performance, highlighting its usefulness as a screening assay for new biomaterials or investigational compounds. Using ISO as a guideline, a material is considered cytotoxic if cell viability falls below 70% of untreated control cells.

LIVE/DEAD STAINING

WHAT IS IT?
The LIVE/DEAD assay is used to determine both cellular membrane integrity and cytosolic enzymatic function in response to a test article. Assay functionality is based on the ability of healthy cells to exclude ethidium homodimer-1, and at the same time cleave the membrane permeable, non-fluorescent calcein AM to calcein through functional cytosolic esterase activity, yielding green cytoplasmic fluorescence. Membrane-compromised cells are permeable to ethidium homodimer-1, which binds to nucleic acids resulting in nuclear-localized red fluorescence.

WHY USE IT?
Unlike most standard cytotoxicity assays, the LIVE/DEAD assay enables concurrent determination of two key aspects of cellular health: membrane permeability and enzymatic function. Healthy cells show green fluorescence, whereas dying or dead cells appear red. Quantification can be carried out by analyzing images that are captured using fluorescence microscopy methods or by using a fluorescence plate reader for high throughput purposes. As such, it provides more detail to the client and can help guide further focused testing.

TUNEL ASSAY

WHAT IS IT?
Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) is used to identify DNA fragmentation, a terminal hallmark of both apoptotic and necrotic cells. Modified dUTPs are incorporated by the enzyme TdT at the 3’-OH ends of fragmented DNA. The modified dUTPs can be fluorescently labeled allowing quantification of apoptotic/necrotic cell number. This assay utilizes a double staining approach where total DNA appears blue and fragmented DNA appears red.

WHY USE IT?
If a test article demonstrates cytotoxicity as determined by MTT or NRU assays, for example, the TUNEL assay is a common approach used to determine whether a cytotoxic response is due to the induction of necrotic or apoptotic mechanisms. Specifically, the TUNEL assay probes for the presence of fragmented DNA, a terminal indicator of imminent cell death.

BRDU ASSAY

WHAT IS IT?
The BrdU assay is based on the fluorometric detection of the thymidine analog BrdU (bromodeoxyuridine), upon its incorporation into genomic DNA during cell proliferation. BrdU may then be detected using anti-BrdU antibodies, allowing assessment of the population of cells that are synthesizing DNA. This provides an indication of cell proliferation rate and a measurement of the number of cells in S phase of the cell cycle.

WHY USE IT?
If a test article demonstrates cytotoxicity as determined by MTT or NRU assays, the client may want to know more. One of the first aspects of cellular function to investigate is DNA replication. The
BrdU assay enables direct comparison between the proliferative status of cells treated with the test article and control cells. A reduction in BrdU uptake by treated cells indicates that DNA replication, and thus cell proliferation, is being negatively impacted.