MARINBIO: Excellence in Cell Based Assays, FDA Compliant for Commercial Pharmaceuticals | LEARN MORE


Cell-based assays or bioassays for biological or biochemical activities are required for every lot of pharmaceutical drug or biopharmaceutical before release. Cell-based bioassays of small molecule pharmaceutical drugs or biologics are integral to and essential for the FDA drug approval process and commercialization.

MarinBio’s deep bioassay expertise includes:

  • Bioassays with primary cells or secondary immortalized/transformed cell lines
  • Commercially available immortalized/transformed cell lines (cell line clones)
  • Customized transfected cell lines (clones/sub-clones) to meet client requirements

Whether a client has already established a cell-based bioassay for transfer to MarinBio or is seeking to newly develop a customized bioassay, our specialized professional experience and bioassay expertise gleaned over 25 years enables highly efficient, rapid and cost-effective routes to successfully completing your cell-based assay-development, -qualification and/or -validation. MarinBio also performs bioassays for lot release,

We are expert at “MarinBio’s Art & Science of Cell Culture”. Scroll down for more information on some of the different assays MarinBio has successfully performed in client contracts.

Cell Morphology Changes With Drug Treatment

SHSY5Y cells are differentiated into neural cells with 7 days treatment with retinoic acid. The cells were treated with or without client drug for 1 additional day. Left Panel: Control (no drug); Right Panel: with client drug. The morphological changes shown are observed from drug treatment.

Drug Concentration Induces Cell Proliferation

CTLL-2 cells are cultured with increasing concentrations of client drug for 4 days. Cell proliferation is measured with Cell Titer Glo. Client drug causes cell proliferation and the 2 standards show precise and identical results.


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Cell-based assays (bioassays) measure functional effects establishing biological relevance and physiological importance. MarinBio contract research and development service professionals are expert in customized or standardized bioassays and measurements of interactions (including small molecules, biologics or device interactions) with cultured cells and primary cells. MarinBio’s Ph.D. scientists have successfully interfaced with the FDA on behalf of our clients, when requested.

Additionally, MarinBio specializes in in vitro cell-based bioassay testing services for clinical and pre-clinical studies, including method development, qualification, validation, transfer, lot release testing and potency testing according to guidelines from both FDA and ICH (International Council for Harmonization). MarinBio has extensive experience with cells and cell-banks (both research level non-GMP/-GLP and GMP/GLP level) of many tissue cell types, clones and develops customized cells, clones and sub-clones. We have developed over 200 different bioassays for our clients during the past 25 years. Some assays we perform are listed below:

Potency bioassays, lot release bioassays
Clinical studies, pre-clinical studies, Sample analyses

ADCC, Antibody-Dependent Cellular Cytotoxicity bioassays
CDC or CMC, Complement-Dependent Cytotoxicity or Complement-Mediated Cytotoxicity bioassays
CTL, Cytotoxic T-Lymphocyte Killing bioassays
ADA, Anti-Drug Antibody Inhibiting Drug Effectiveness (Neutralization bioassay)
FLOW Cytometry bioassays, Reporter and Protein Expression
FLOW Multiplex Cytokine Assays, FLOW High-Throughput bioassays
MLR, Mixed Lymphocyte Reaction bioassays

Cell Enzyme bioassays
Cell Proliferation bioassays
Cell Signaling at Cell Surfaces or Intracellular Signaling bioassays
Cell Toxicity, Apoptosis and Necrosis bioassays
Cell Transfection and Transient or Stable Gene Transcription and Protein Expression bioassays

Agonist/Antagonist bioassays
Drug Combination bioassays
Drug Delivery bioassays
Drug Metabolism bioassays
Drug Subcellular Fractionation and Localization bioassays
Drug Target Pathway and Phosphorylation bioassays

Gene activation, modification by transfection, expression bioassays
Mechanism of action bioassays
Receptor, Protein Binding and Turnover bioassays
Reporter bioassays

Exosome bioassays
Metabolic bioassays
Migration and Wound Healing bioassays


From the beginning and ongoing, your assay is a critical component of the life cycle of your current or eventual product. That is precisely why you want experience and expertise at the earliest possible stage of your development.

When you require an assay to prove your science and there is no commercial kit available, you need a custom assay. MarinBio’s extensive expertise enables rapid and methodical development of your assay for eventual validation. Typically, a custom assay can be developed from the inception to a completed bioassay in 5 or less experiments, while minimizing any effects of the matrix.

MarinBio expert at preparing and validating GMP/GLP or research level cell banks. The banks could include primary cells or cell lines for specific bioassays, as well as cell bank uses for production, isolation and characterization of genetically defined clonal cell populations and small-scale manufacturing of biologic products.

MarinBio professionals have vast experience with improving cell culture growth, freezing, serum-free culture, cloning for client bioassays, as well as transfection with DNA or RNA and/or liposomes (lipofection) for genetically variant cell lines as well as for gene or protein expression bioassays.

Our scientists have developed over 200 custom bioassays involving growth, toxicity, transfection, cell surface, cytokine or gene expression. We are your scientists; MarinBio will make your GMP potency lot release assay or drug screening assay.

Many companies planning an IND submission or in Phase I/II may only require a well-qualified assay, rather than a fully validated assay. You may or may not need GLP/GMP stringency and auditability. The expert MarinBio scientific team works with your scientists to qualify your assay for reproducibility, appropriate precision and accuracy, with validation in mind for the future.

To validate an assay, the precision, linearity, accuracy, robustness, system suitability and repeatability is measured to meet acceptance criteria. We in-source your assay or fully develop and validate an assay to meet the FDA GLP or GMP requirements.

When patient samples or drug product samples need analysis, MarinBio will map out a timeline and follow through with sample receipts, meeting your regulatory needs at all points. We perform your assay as a developed, qualified or validated bioassay, and promptly communicate the results and/or provide a Certificate of Testing for any or all of your pre-clinical or clinical phases.

Knowing the importance to the FDA of lot release potency testing data, our professional scientific team tests every manufactured lot with your assay and provides Certificates of Testing.

In order to determine shelf-life for a particular drug substance, stability tests are performed at pre-determined calendar intervals. MarinBio’s expert project coordinators communicate closely with you to anticipate the arrival of samples in order to be prepared for timely analysis and the submittal of data and Certificates of Testing.


The complexity of successful cell-based bioassay and bioanalysis demands advanced bioassay skills, cell culture expertise and knowledge of the bioassay parameters, as well as the FDA regulatory standards. The MarinBio senior Ph.D. scientific staff averages 15-25 or more years of professional experience in designing and developing cell-based bioassays, as well as interfacing on behalf of our clients with the FDA, when requested. We have developed and perfected a comprehensive, rapid, cost effective approach for successful cell-based bioassays, including client customized bioassays that are technically demanding and intricate.

MarinBio’s Art & Science of Cell Culture