Table 2 Summary of gelatin/GelMA-based nanobioinks used to fabricate various in vitro tissue types

Gelatin or GelMA

Dialdehyde cellulose (DAC) nanocrystal

Natural cross-linker to enhance the mechanical properties of gelatin hydrogel

* Porous scaffold in different shapes (circle, regular hexagon, square)

Tissue repair (not specific)

[184]

TEMPO-oxidized cellulose nanofibrils (CNFs)

Viscosity regulator and facilitator for the cross-linking of GelMA

Porous lattice and simple disc structure

Wound-healing scaffold

[185]

nHAp

Osteoconductive factor

Mechanical reinforcer

* Tri-layered hierarchical scaffold

Bone and cartilage

Osteochondral tissue

[161]

* Porous lattice scaffold

Bone tissue

[162]

Nanosilicate

Printability enhancer

Osteoinductive cues

Potential vehicle for drug retention and delivery

Porous lattice structure

Angiogenic bone tissue

[69]

Osteoinductive cues

Pyramidal constructs containing a perfusable vasculature inside

Vascularized bone tissue

[182]

Graphene nanoplatelets

Mechanical reinforcer

Neuronal differentiation cues

Porous lattice structure (stereolithography-based printing)

Electro-active tissues

Neural tissue

[186]

GNRs

Electrically conductive bridges connecting electroactive cardiomyocytes

30-layered constructs with inner grids (direct printing) and spiral constructs (embedded printing)

Cardiac tissue

[183]

Gold nanoparticles (AuNPs)

Printability enhancer

Electrically conductive bridges connecting electroactive myoblast

Dot shape

Skeletal muscle tissue construct

[187]

Limitations of gelatin-based systems

Despite its extensive utilization across various biomedical fields, its relatively weak mechanical properties limit its application in specific applications (i.e. load-bearing tissues)