Table 1.

The most popular polymers for scaffolds fabrication, their main advantages and limitations and current potential application in different tissue engineering fields.

POLYMER	TYPE	EXAMPLE	ADVANTAGES	LIMITATIONS	PROMISING IN	REF.
Natural	polysaccharides	chitosan	biocompatibility, hemostatic activity, biodegradability, antibacterial activity, easily metabolized	stiff, brittle, low mechanical resistance	skin, nervous, bone, cartilage, cardiac, liver, and muscle tissue engineering	[[17], [18], [19], [20], [21], [22], [23]]
		cellulose	biocompatibility, bioactivity, good mechanical properties depending on the source	non-biodegradable	skin, neural, bone, cardiovascular, muscle, tendons, cartilage regeneration	[[24], [25], [26], [27], [28]]
		alginate	biocompatibility, non-immunogenicity, biodegradability, non-antigenicity, bioactivity	limited strength, toughness, difficulty in controlled gelation	skin, cartilage, bone, neural regeneration	[20,[29], [30], [31], [32], [33], [34]]
		hyaluronic acid	biocompatibility, biodegradability, easy chemical modification, bioactivity	poor mechanical properties, rapid degradation	neural, skin, regeneration	[[35], [36], [37], [38], [39], [40], [41], [42]]
	proteins	collagen	biocompatible, biodegradable, ECM mimicking, poorly immunogenic, bioactive	poor mechanical properties,	skin, cornea, dental, vascular, cartilage, bone regeneration	[41,[43], [44], [45], [46], [47], [48]]
		gelatin	biocompatible, biodegradable, ECM mimicking, low immunogenic, inexpensive, water-soluble, bioactive	poor mechanical properties, fast enzymatic degradation, low solubility in concentrated aqueous media	skin, bone, cartilage, adipose neural, regeneration	[[49], [50], [51], [52], [53], [54]]
		fibrin	biocompatible, biodegradable, ECM mimicking, low immunogenic	rapid degradation rate, poor mechanical properties, expensive, risk of contamination	liver, retina, cartilage, vascular, neural regeneration	[[55], [56], [57], [58], [59]]
		silk fibroin	biocompatibility, biodegradability, bioactivity, low immunogenic, high tensile strength, excellent mechanical properties, water-based processing, low cost	Weak, brittle as scaffolds.	skin, vascular, bone, cartilage, tendon, cornea, hepatic, Neural regenration	[[60], [61], [62], [63], [64], [65]]
		elastin	biocompatibility, bioactivity, good biophysical and biomechanical properties	Water-insoluble, difficult to manipulate in vitro, risk of contamination, risk of inflammation, difficulties in sourcing	skin, cartilage, cardiovascular, tendon, skin, liver regeneration	[[66], [67], [68], [69], [70], [71], [72]]
Synthetic	Biodegradable	PCL	biocompatible, easy to modificate and fabricate, good organic solvent solubility, controllable degradation rate, inexpensive, good mechanical properties, thermoplastic	poor cellular adhesion due to hydrophobicity, relatively slow degradation rate (2–4 years),	skin, bone, vascular	[[73], [74], [75], [76], [77], [78]]
		PLA	biocompatibility, easy to modificate and fabricate, obtained from renewable sources,	lack of bioactivity, low cell adhesion, biological inertness, acid degradation by-products, risk of inflammation, low porosity, low degradation rate (but faster than PCL)	skin, bone, cardiovascular, cartilage, ligament, neural regeneration	[[79], [80], [81], [82], [83], [84], [85]]
		PGA	biocompatible, bioresorbability, high tensile strength,	fast degradation rate, acidic degradation products, low solubility	bone, cartilage, ligament regeneration	[[86], [87], [88], [89], [90], [91]]
	Non-biodegradable	PDMS	biocompatibility, easy to fabricate, flexible, thermo-tolerant, tunable hardness, good biostability, the high solubility of oxygen in PDMS,	non-bioactivity due to hydrophobicity, non-biodegradable	skin, bone, neural regeneration	[[92], [93], [94], [95], [96]]
		PPy	electrical conductivity, easy to synthesized, environmental stability, low inflammatory response,	non-biodegradable, not easy to modify, non-thermoplastic, water insoluble, mechanically rigid, brittle, possible long-term toxicity, non-biodegradable	neural cardiovascular, liver regeneration	[[97], [98], [99], [100], [101], [102], [103], [104]]
		PVDF	piezoelectric properties, high flexibility, non-toxicity, chemical and physical resistance	hydrophobicity, insufficient biocompatibility, non-bioactive, non-biodegradable	bone, neural, bladder, skeletal muscle regeneration	[[105], [106], [107], [108], [109], [110]]