Sustained release growth factors: PODS

The Polyhedrin Delivery System (PODS™) from Cell Guidance Systems release a steady stream of active growth factors over days, weeks or months, making them ideal for organoid and spheroid cultures by improving cell health and phenotypes by the prolonged presence of active growth factors in the culture environment.

PODS structure
PODS growth factors consist of two proteins: An active protein (e.g. a growth factor) is encased within a polyhedrin microcrystal actually inside the insect expression cell to form a co-crystal. This polyhedrin casing protects the active protein during the purification of the growth factor ensuring the growth factor is not denatured and is correctly folded and functional.

Benefits of using the PODS growth factors
• Sustained protein release for days, weeks and months
• Reduced frequency of cell culture media changes
• Development of physiologically relevant concentration gradients for patterning
• Significantly stabilises growth factor concentrations available in media for more predictable cell behaviour

PODS growth factors generation

PODS crystals are generated in cells in which the polyhedrin protein is expressed at high levels under the control 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 termed the active, or cargo, protein. The active protein is tagged with a short peptide sequence which causes enables the active protein to bind to the growing polyhedrin crystal. As the cubic crystal continues to grow, the active protein becomes encased.

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

Applications
• Physiological, stable gradient formation
• 3D culture including organoids
• Functionalising scaffolds
• Microfluidics (lab on a chip)
• In vivo survival agent for implanted cells
• Therapeutic protein delivery

PODS citations

Material avaible for download
PODS user guide
Application note: Generating growth factor gradients with PODS crystals
Application note: Modulating protein release rates from PODS crystals
Application note: Creating PODS crystal monolayers on multi-well tissue culture plates
PODS brochure

Below is a small selection of PODS available. To find the product you need, contact our Cell Guidance Systems specialist.