NOVEL MICROSPHERES FOR PROLONGED CELL SURVIVAL - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 641

Table32.1. Basicaspectsinvolvedinandconsidereddur-
ing thedevelopment of ORMs.
Process involvedin developing ORMs
1. Identification of asuitable oxygen-generating source
2. Selection of materials that can beused as building blocksfor ORMs
3. Selection of a suitable techniquefor encapsulating theoxygen source
4. Thestudy of oxygen-releasing profiles.
5. Incorporation of a suitable agent todecompose thesource (if required)
6. Storageand integration of ORMs into applications
case as the encapsulation of the gas is often di cult and gives low
loading e ciency. If the gas is to be compressed in achieving higher
concentration for encapsulation, a shell of ultra strength is required
to sustain the pressure and is often unachievable by the commonly
used biodegradable matrices. Having the oxygen source identified,
the next factor to be considered is the materials that can be used
to form the shell of the microspheres. Whether synthetic or natural,
the material chosen should be biocompatible, pose no interference
reaction with the other ingredients, and be preferably biodegrad-
able. The utilization of hybrid materials having high suitability for
tissue engineering tasks, formed from the homogenous blending of
different matrices, is also a good option. In addition, microspheres
can be formed via combination of different materials as long as the
layers are attaching to each other. Upon having all the ingredients,
a suitable method can be chosen based on the capability of forming
microspheresandatthesametimeencapsulatingtheoxygensource.
E cient encapsulation should be achieved without decomposing
the source during the process. There are many techniques reported
fortheencapsulationofcompoundsintomicrospheres,especiallyin
drug delivery systems that can be readily modified or improved. 3 , 45
An ideal technique should be simple and highly reproducible, use
nontoxic materials, involve no sophisticated instrumentations, and
have a short processing time. The microspheres produced require
evaluation for their oxygen-releasing profile, and if necessary, an
activating mechanism to transform the source into oxygen will be
integrated.Theactivationmaybeinducedbymechanicalforce,ther-
mal heat, electromagnetic radiation, catalyst, etc. In having a more