Table 2.
3D-printed microneedles for transdermal drug delivery.
| 3D Printing Technology | Needle Type | Shape | Geometric Features | Ref. |
|---|---|---|---|---|
| FDM | Hollow | Pyramid | Lengths: 800–3000 μm Base sizes: 500–1500 μm Opening diameters: 200–500 μm Spacings: 1500–3000 μm |
[119] |
| Solid | Tapered cone | Length: 4500 μm Base diameter: 1500 μm Tip diameter: 500 μm Spacings: 250–750 μm |
[117] | |
| Drug-loaded MN | Conical | Length: 800 μm Base diameter: 700 μm Spacing: 1100 μm |
[19] | |
| Solid | Cylindric | Lengths: 1450–2000 μm Widths: 465–600 μm |
[32] | |
| Drug-loaded MN | Cylindric | Lengths: 200–2500 μm Widths: 400–600 μm Tip diameters: 170–220 μm |
[26] | |
| SLA | Drug-loaded MN | Cross-shaped | Length: 1000 μm Width: 1000 μm Length of fins: 430 μm |
[96] |
| Drug-loaded MN | Pyramid and flat spear-shaped | Length: 1000 μm Base dimensions: 1000 × 1000 μm (pyramid), 80 × 1000 μm (spear) |
[126] | |
| Drug-loaded MN | Pyramid and cone | Length: 1000 μm Base dimensions: 1000 × 1000 μm (pyramid), ø 1000 μm (cone) |
[33] | |
| Hollow | Conical, pyramid, and syringe-shaped MNs | Lengths: 700–900 μm Base width: 800 μm Center bore: 600 μm |
[64] | |
| Drug-loaded MN | Cone MNs on a curved and flat patch | Length: 800 μm Base diameter: 400 μm Tip diameter: 100 μm Interspacing: 800 μm |
[125] | |
| Drug-loaded MN | Cone | Length: 900 μm Base diameter: 300 μm Interspacing: 1800 μm |
[45] | |
| DLP | Solid | Rectangular pyramid shapes | Lengths: 1000–1250 μm Base dimensions: 500 × 250 μm, 750 × 250 μm Tip dimensions: 90 μm × 30 μm |
[130] |
| Drug-loaded MN arrays | Tapered cone | Body: a cylindrical base with a length of 700 μm Tip: a conical tip with a length of 300 μm |
[124] | |
| Hydrogel MNs | Cone | Length: 700 μm | [137] | |
| LCD | Hollow | Cone, square pyramid, screw, and triangular pyramid | Length: 1000 μm Interspacing: 3000 μm |
[138] |
| CLIP | Coated | Square pyramidal | Length: 1000 μm Base wide: 333 μm Spacing: 1000 μm |
[140] |
| Drug-loaded MN | Arrowhead, tiered, and turret MNs | Lengths: 600–1000 μm Width: 400μm (tiered MNs) Length: 1000 μm Width: 500μm (turret MNs) |
[139] | |
| TPP | Hollow | Cone and cylinder | Length: 435 μm Base diameter: 100 μm Tip diameter: 35 μm |
[148] |
| Hollow | Beveled tip | Lengths: 200–400 μm Diameters: 80–120 μm |
[143] | |
| Hollow | Truncated cone-shaped MN arrays | Lengths: 250–300 μm Base radii: 100–187.5 μm Tip radii: 15–20 μm |
[144] | |
| Solid | Ultra-sharp cone MNs | Length: 200 μm Shank radius: 50 μm Tip radius: 0.5 μm |
[109] | |
| Coated MN | Cylindrical, conical, and pyramidal MNs | Length: 6 μm Tip diameter: 630 ± 15 nm |
[142] | |
| DMLS | Solid | Cone | Length: 1000 μm Base diameter: 250 μm Interspacing: 1500 μm |
[156] |
| SLM | Hollow | Cylindrical | Length: 1200 μm Tip diameter: 160 μm |
[158] |
FDM: Fused deposition modeling, SLA: Stereolithography, DLP: Digital light processing, LCD: Liquid crystal display, CLIP: Continuous liquid interface printing, TPP: Two-photon polymerization, DMLS: Direct metal laser sintering, SLM: Selective laser melting.