Scaffolds for Growth Factor Delivery as Applied to Bone Tissue Engineering
Table 4
Current strategies for growth factor delivery in bone tissue engineering and the associated advantages and drawbacks.
Delivery system
Release characteristics
Advantages
Drawbacks
Supercritical CO2
Sustained release
Good encapsulation efficiency Very high bioactivity retention Solvent less formation
Limited available scaffold conformations suitable for bone tissue engineering Complex equipment requirement for manufacture
Electrospinning
Varying release
Rapid fabrication of scaffold Large number of polymers available for electrospinning
Limited available scaffold conformations suitable for bone tissue engineering Requires organic solvents which can denature GFs and reduce bioactivity Limited information on encapsulation efficiency Limited information on release characteristics
Nano/microspheres
Initial burst then slow sustain
Several techniques available for fabrication Easy to combine with other scaffold fabrication techniques
Limited available scaffold conformations suitable for bone tissue engineering Requires organic solvents which can denature GFs and reduce bioactivity Classical formation techniques have poor encapsulation efficiency
Hydrogels
Short-term release
Can be injected into wound sites (in situ formation) Good encapsulation efficiency Solvent less formation Easy to combine with other techniques
Rapid degradation of most commonly used hydrogels Unsuitable mechanical characteristics for bone tissue engineering
Functionalisation of surfaces, for example, polyelectrolyte systems nanocoating, and so forth.
Short-term release
Can be applied to scaffolds with good mechanical properties High bioactivity retention
Technique is time intensive Alters existing surface chemistry