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International Journal of Bioprinting Unique characteristics of 3D-printed microneedles

Table 2. Different 3D printing microneedle technologies
Technology Resolution Microneedle type Advantages Disadvantages
Extrusion (FDM) 50–200 μm 45 Solid (biocompatibility) 46 High speed, low cost, simple Low accuracy, poor printing quality 47
operation 45
Extrusion (DIW) 1–250 μm 48 Solid (biocompatibility) 49 Short time consumption, low cost, Low accuracy, currently unable to be used
simple operation 48 as a separate method 49
VP (SLA) 10 μm 45 Solid, hollow, coated 10 High precision, capable of Material limitations, time-consuming, and
manufacturing complex structures expensive 45,47
with good surface quality 45,47
VP (DLP) 25–100 μm 47 Solid, hollow, coated, High precision, fast speed, and Material limitations and unstable
hydrogel 10,50 low cost 47 structure 47
VP (TPP) 100 nm–5 μm 47 Solid, hollow, coated 51,52 High printing accuracy 53 Slow speed and expensive 54,55
VP (LCD) 50 μm 56 Solid, hollow, coated 56 High precision, low cost, high High component demand and small
speed 56 printing area 57
VP (CLIP) 50–100 μm 10 Solid, coated, hydrogel 10 Smooth surface 58 Low-viscosity resin is required 59
VP (SOPL) 100–300 μm 60 Solid, hollow, coated 61 Fast speed, good mechanical Requiring transparent materials 61
properties 60
PBF (SLS/SLM) 50–250 μm 47 Solid, hollow 62 High precision, high mechanical The price of equipment and materials is
performance, no support high, and the reusability of unsintered
required 47 powder is poor 9
Abbreviations: CLIP, continuous liquid interface production; DIW, direct ink writing; DLP, digital light processing; FDM, fused deposition molding;
LCD, liquid crystal display; SLA, stereolithography; SLM, selective laser melting; SLS, selective laser sintering; SOPL, static optical projection
lithography; TPP, two-photon polymerization; VP, vat photopolymerization.
Table 3. Properties of 3D printing microneedles
Technology Microneedle type Parameters Mechanical properties (fracture force) Ref.
FDM Solid Shape: Cylindric Fracture force: 0.23 N (after etching) 49
Heights: 200–2500 μm
Widths: 400–600 μm
Tip diameters: 170–220 μm
Solid Shape: Cylindric Fracture force: 10.5 ± 1.3 N (3 × 3) 64
Height: 1000 μm (after etching)
Base diameter: 700 µm
Tip diameters: 97 ± 21 μm
Solid Shape: Cylindric Fracture force: 36.0 ± 0.48 N (after 63
Height: 1500 µm etching)
Base diameter: 1000 µm
Tip diameter: 500 µm
DIW Solid Shape: Conical Penetrate the skin of mice 65
Lengths: 800 μm
Base diameter: 700 μm
Spacing: 1100 μm
SLA Solid Shape: Cross-shaped Penetration force: 2.2545 N 75
Height: 1000 µm (displacement: 1.8 mm)
Lengths of four fins: 430 µm
Solid Shape: Spear and pyramid Fracture force (spear): 175 N 78
Height: 1000 μm Fracture force (pyramid): 457 N
Base dimensions (Spear): 0.08 × 1 mm (6 × 8)
Base dimensions (Pyramid): 1 × 1 mm
Hollow Shape: Conical Fracture force: 350–400 N 67
Height: 1150 μm (7 × 7)
Base diameter: 950 μm
Inner diameter: 560 μm
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Volume 10 Issue 4 (2024) 65 doi: 10.36922/ijb.1896