Table 1.

Types of commonly employed biodegradable polymers for the fabrication of scaffolds, their characteristics, and recent biomedical applications.

Biopolymer type	Biopolymer	Sustainability credentials for biomedical applications	AM technique	Advantages	Disadvantages	Degradation time	Suggested polymers and bio-ceramics to develop composites	Formulations	Biomedical applications	Ref.
Natural	Chitosan	Biodegradable Low carbon footprint	Extrusion, SLA	Non-immunogenicity, easily metabolized, antibacterial activity, and biocompatibility	Low mechanical strength, brittle, stiff	>20 weeks	HAp, BG, alginate, or collagen	Sponge, hydrogels, composite scaffolds	Gene delivery, wound dressing, bone, nervous, skin, liver, cardiovascular, and cartilage TE	[65], [66], [67]
	Alginate	Lower carbon footprint Biodegradable	Extrusion	Non-immunogenicity, bioactivity, biocompatibility, and non-antigenicity	Limited toughness and mechanical strength	80 d	BG, HAp, chitosan, or PLA	Micro/nanosphere, hydrogels	Hollow vascular channels, bone, cartilage, neural, skin regeneration, and wound healing	[68], [69], [70]
	Cellulose	Excellent biodegradability Low carbon footprint	DIW, FDM, IJP	Bioactivity, excellent mechanical characteristics, and biocompatibility	Limited cell adhesion	Weeks to months	HAp, CNTs, chitosan, PLA, or PBS	Composite scaffolds	Neural, skin, tendons, muscle, cardiac, cartilage, and bone regeneration	[71], [72], [73], [74]
	Collagen	Biodegradable Low embodied energy level and carbon footprint	Extrusion, IJP	High porosity, bioactivity, excellent mechanical characteristics, biocompatibility, and poor immunogenicity	Low antigenicity, low mechanical strength, and low stiffness	12 h	HA, PLGA, BG, or HAp	Scaffolds	Drug delivery, vascular, dental, cornea, bone, cartilage, and artificial skin regeneration	[75], [76], [77]
	SF	Excellent biodegradability Low carbon footprint	Micro-extrusion, SLA, IJP	Biocompatibility, excellent mechanical characteristics, high tensile strength, bioactivity, high flexibility, and low immunogenicity	Brittle, rapidly degrade	6 weeks	Collagen, HAp, PLA, or calcium phosphate	Scaffolds	Gene delivery, wound healing, hepatic, vascular, cornea, neural, tendon, bone, cartilage, and skin regeneration	[78], [79], [80], [81]
	Gelatin	Biodegradable Low embodied energy level	Extrusion, SLA	Biocompatibility, bioactivity, ECM mimicked, poor immunogenicity, and better solubility	Rapid degradation, low mechanical strength, limited solubility in concentrated solutions	10 d	Chitosan, HAp, PLA, or PCL	Micro/nanosphere, hydrogels	Aortic valves, neovascularization, cartilage, neural, bone, and skin regeneration	[82], [83], [84]
	Starch	Excellent biodegradability Low carbon footprint	Extrusion	Non-toxicity and biocompatibility	Brittle and less surface area	Several weeks	GO, BG, or PCL	Composite scaffolds	bone, skin regeneration, and drug delivery systems	[85], [86], [87], [88]
	HA	Biodegradable Low embodied energy level	Extrusion	Non-toxicity, easily modified through chemical reaction, and biocompatibility	Fast degradation rate and low mechanical characteristics	4 months	PEG, PLA, PLGA, collagen, or chitosan	Scaffolds, hydrogels	Skin and neural regeneration	[89], [90], [91]
Synthetic	PLA	PLA degradation within the human body PLA copolymers, which can help in the adjustment of degradation	Extrusion, SLA, IJP	Highly flexible and biocompatible	Highly inflammable, low cellular adhesion, porosity and bioactivity, poor rate of degradation	20 months	HA, alginate, chitosan, PCL, HAp, or BG	Hydrogels, composite scaffolds	Suture, neural, bone, skin cartilage, cardiovascular, ligament regeneration, and drug delivery applications	[92], [93], [94]
	PCL	Slow degradation rate Water, solvent, oil, and chlorine resistant	Extrusion, SLA, IJP	Highly flexible, excellent mechanical characteristics, degradation and solubility, biocompatible, and minimal inflammability	Limited degradation and low cell adhesion	6–28 months	Chitosan, PLA, BG, or HAp	Composite scaffolds, hydrogels	Dentistry, vascular, bone, retina, skin regeneration, and pharmaceutical applications	[95], [96], [97]
	PGA	Insoluble in water Biodegradable	Extrusion, SLA, IJP	Excellent tensile strength, bioresorbable, and biocompatible	Limited solubility and rapid degradation	5 months	PLA, PEG, PLGA, collagen, or chitosan	Composite scaffolds, hydrogels	Surgical sutures, bone, ligament, and cartilage reconstruction	[98], [99], [100], [101]
	PHB	Biodegradable	Extrusion, IJP	Excellent mechanical, barrier properties, piezoelectricity, and optical activity	Limited solubility, and low cell adhesion	6–10 months	Chitosan or alginate	Composite scaffolds, hydrogels	Surgical implants, biomedical devices, bone, skin, cartilage regeneration, or breast augmentation	[102], [103], [104]
	PVA	Biodegradable Low carbon footprint	Extrusion, IJP	Biocompatibility, non-toxicity, self-healing property, and hydrophilicity	Low cell adhesion	16–25 d	Gelatin, chitosan, PLA, or PGA	Hydrogels, composite scaffolds	Drug delivery, wound dressing, bone, cartilage, and skin regeneration	[105], [106], [107]