The Polyhedrin Delivery System (PODS™) from Cell Guidance Systems ensures a continuous release of active growth factors over extended periods, ranging from days to months. This makes them highly suitable for organoid and spheroid cultures, enhancing cell health and phenotypes through the sustained presence of active growth factors in the culture environment.


PODS structure

PODS growth factors are composed of two proteins: an active protein, such as a growth factor, encased within a polyhedrin microcrystal actually inside the insect expression cell to form a co-crystal. This polyhedrin shell protects the active protein during the purification process, ensuring it remains undamaged, properly folded, and functional.


Benefits of using PODS growth factors

  • Continuous protein release for extended durations (days, weeks, months)
  • Decreased need for frequent cell culture media changes
  • Development of physiologically relevant concentration gradients for patterning
  • Enhanced stabilization of growth factor concentrations in the media, leading to more consistent cell behaviour


Generation of PODS growth factors

PODS crystals are produced in cells where the polyhedrin protein is expressed at high levels under the regulation of the polyhedrin promoter. PODS crystals are formed when a second protein, also under the control of a polyhedrin promoter, is coexpressed. This second protein is known as the active or cargo protein. The active protein is tagged with a short peptide sequence that allows it to bind to the developing polyhedrin crystal. As the cubic crystal grows, the active protein becomes encased.


PODS growth factors sustained release formula maintains cells in the optimal growth factor zone



  • Formation of stable physiological gradients
  • 3D cultures, such as organoids
  • Functionalization of scaffolds
  • Microfluidics (lab-on-a-chip systems)
  • In vivo survival agent for implanted cells
  • Therapeutic protein delivery



Download Literature:
PODS user guide
PODS brochure
PODS in vivo applications
Use of PeptiGels® functionalized with PODS® for complex 3D in vitro culture
PODS® sustained release technology for use in therapeutic protein delivery
Growth factor release from PODS® crystals in serum-free medium