NIST selects VitroGel® as material to generate the ASTM standard for measuring cell viability in scaffolds.

The National Institute of Standards and Technology (NIST) aims to establish a standard for measuring cell viability in scaffolds. NIST selected VitroGel®, an advanced hydrogel system known for its xeno-free composition, biocompatibility, transparency, and ease of use. VitroGel®’s unique formulation supports cell growth and differentiation, making it an ideal choice for creating a reliable and reproducible environment for assessing cell viability within three-dimensional scaffolds.  

This selection emphasizes VitroGel®‘s potential to facilitate significant advancements in scaffold-based cell culture studies. 

VitroGel® is the next generation of xeno-free functional hydrogels that closely mimic the natural ECM bridging in vitro and in vivo studies through 3D cell culture. 

  • Xeno-free, biological functional hydrogel
  • Ready to use at room temperature 
  • Supports a wide range of cell types and applications 
  • Easy, efficient, and enzyme-free cell harvesting in 20 min 
  • Batch-to-batch consistency to ensure reproducible results

LEARN MORE ABOUT VITROGEL® HYDROGELS​ >

About NIST

The National Institute of Standards and Technology (NIST) is a U.S. federal agency that promotes innovation and industrial competitiveness by advancing measurement science, standards, and technology to enhance economic security and improve the quality of life. 

Project Scope

The standard for measuring cell viability in scaffolds aims to advance measurements of cell viability in manufactured tissues and the following:  

  • Establish a working group of industry stakeholders to guide work.
  • Develop model scaffold-cell-assay system for measuring cell viability in scaffolds. 
  • Validate measurement system by orthogonal test methods. 
  • Assess reproducibility of measurement system by conducting an inter-laboratory test. 
  • Write ASTM standard test method for measuring cell viability in scaffolds, supported by results from work described above. 
  • Use model scaffold-cell-assay system to assess advanced methods for measuring cell viability in scaffolds (especially non-invasive imaging methods).

Motivation

The motivation behind this project stems from the critical role that cell viability plays in the effectiveness of tissue-engineered medical products, which typically consist of cells seeded onto a scaffold. Cell viability is often measured as a quality attribute, as live cells are essential for regenerating tissue or secreting factors that induce regeneration. However, scaffolds can interfere with viability tests in various unknown ways, such as slowing the diffusion of assay components or interacting with these components to skew results. This project aims to address these challenges, ensuring accurate and reliable measurement of cell viability in scaffold-based products. 

Project Details 

A. MATERIALS

Scaffold: Glucose-based polysaccharide Gel 

  • Hydrogel represents the “worst-case scenario” for interfering with bioassays (slowing diffusion of assay components) 
  • Shear thinning gel which can be disassembled by pipetting action: this is key for releasing cells from gel to confirm in situ-results 
  • Source: VitroGel® (TheWell Bioscience)

Assay: ATP/DNA 

ATP Luminescence Assay 

  • Bioluminescence assay for quantitative determination of ATP (moles) 
  • Used for release of haematopoetic stem cells for clinical use 
  • Source: CellTiterGlo-3D Luciferase Assay (Promega) 

Fluorescence DNA assay 

  • Fluorescence assay for quantitative determination of ATP (grams) 
  • Source: PicoGreen dsDNA Assay Kit (ThermoFisher) 

Cells: Jurkat 

  • Human T lymphocytes 
  • Non-adherent cells should not undegro anoikis in polysaccharide hydrogel that lacks cell adhesion sites 
  • Source: Jurkat, Clone E6-1, ATCC TIB-152 

B. VALIDATION SCHEME 

This is a high-level overview of the types of tests being conducted to develop the validated test method 

  • Luminescence ATP assay 
    • ATP spike-into hydrogel
    • ATP spike-into hydrogel then disassembly via shear-thinning 
    • Jurkat Cells in hydrogel 
    • Jurkat Cells in hydrogel then disassembly via shear-thinning 
  • Fluorescence DNA assay 
    • DNA spike-into hydrogel
    • DNA spike-into hydrogel then disassembly via shear-thinning 
    • Jurkat Cells in hydrogel 
    • Jurkat Cells in hydrogel then disassembly via shear-thinning 

Value 

The test system, protocols, and ASTM standard intend to provide a guide for researchers to develop strategies for validating measurements of cell viability in scaffolds. Additionally, the standard will serve as an essential training tool for scientists new to this work process. The model scaffold-cell-assay system can also be used as a test bed to evaluate advanced measurements of cell viability in scaffolds, especially less invasive or 3D imaging techniques (EPROI, photonic sensing, photoacoustic imaging, fluorescence lifetime, optical coherence tomography).  

ASTM Work Item

WK62115: Standard Test Method for Measuring Cell Viability in a Scaffold 

For more information on the project, visit https://www.nist.gov/mml/bbd/biomaterials/measuring-cell-viability-scaffolds