Table 3.

Most common synthetic polymers used in tissue-engineered scaffolds in cell transplant therapies for the treatment of glaucoma

Polymers	Chemical structure	Bio-degradation	Features	Selected references
PLA		12–24 months–(depending on crystallinity)	PE backbone containing unsubstituted, unreactive methyl groups; displays a variable degree of crystallinity; chemically stable; mechanically robust; highly permiable; a radical scavenger; degrades via bulk erosion	[2, 44, 114, 115, 163]
PLGA		1–6 months	PE backbone similar to PLA containing extended co-polymer mixture (i.e., lactide and glycolide); degradation rate can be tailored depending on the molecular weight and co-polymer ratio(s); degrades via bulk erosion	[2, 45, 84, 108, 116, 117, 163]
PCL		Over 24 months	Simple unsubstituted PE backbone; a long 6-pento-methyline bridge offers an enhanced flexibility and an ability to be modified using various physico-chemical processing steps; partially crystalline; chemically stable and mechanically robust; degrades via bulk erosion	[84, 85, 108, 118, 120–123, 163, 164]
PGS		1–2 months	PE backbone, di-carbon acid and di-ethyl flexible chain offer similar to PCL processability, substituted glycerine moiety allows fine tuning of physical and chemical properties via -OR modification; highly customisable; degrades into glycerol and sebacic acid via surface erosion	[2, 124]