Table 1.

Typical polymers—general properties and fabrication of polymeric MNs.

Material	Advantages	Limitations	Fabrication Techniques	References
1. PVA	Low material costs Good plasticity Dissolvability and nontoxicity	Greater rate of absorbency	Molding fused deposition method (FDM)	[23,24]
2. PLGA	Preparation of dissolving microneedles (MNs)	Material costs are high	Molding, hot embossing	[25,26]
3. HA	Faster rate of dissolving	Chances of skin irritability	Micro-molding	[27]
4. PCL	Good thermal stability High rate of permeability	Process of slow degradation	3D printing, micro-molding	[28,29]
5. PEGDA	Can penetrate easily into molecular spaces	High material cost	Photolithography	[30]
6. PGA	Faster rate of degradation Exceptional mechanical strength	High material cost	Injection molding technique lithography	[31,32]
7. PLA	Higher rates of tensile strength Excellent physical and mechanical rigidity	Costly material Slower rate of degradation	Molding	[33,34,35]
8. PVP	Good plasticity and dissolvability	Difficulty in fabrication	Molding and photo polymerization	[36]
9. PDMS	Good biocompatibility and flexibility	Less penetrability	Micro-molding, curing	[37]
10. Poly (Ethylene Glycol-co-methacrylic-acid)	Good biocompatibility	Good drug transport mechanism	Bulk polymerization	[37]
11. Cellulose acetate	Good base material	Bio fluid extractions/insulin delivery	Mold casting method	[37]
12. PGMA	Good penetration efficiency	Drug delivery/ISF sampling	photopolymerization	[37]

Abbreviations: PVA: polyvinyl alcohol, PLGA: poly lactic-co-glycolic acid, HA: hyaluronic acid, PEGDA: poly (ethylene glycol) diacrylate, PGA: polyglycolide; PLA: poly (lactic acid), PVP: polyvinylpyrrolidone, PDMS, Poly (Ethylene glycol-co-methacrylic-acid), PGMA: Poly Glycidyl methacrylate.