Table 2 Representative fabrication methods for building blocks

3D cell culture

Organ buds from endothelial cells and MSCs cultured with tissue-specific progenitors or relevant tissue samples

[28]

Generative potential

Promote vascularization

Limited productivity

Strict culture condition

Mouse or human ISC-derived organoids in PEG hydrogels

[29]

Printed hMSCs cultured in alginate microgel

[30]

HiPSCs aggregates suspended in ECM solution to form embryoid bodies

[31]

Emulsification

Hollow spherical cell aggregates in gelatin microbeads generated by emulsification in oil bath

[32]

Easy to operate

Moderate condition

Little control over size

Microtissues of MSCs in chitosan-collagen matrix suspended in oil

[33]

Microfluidics

PEGDA microgel containing single MSC or chondrocyte produced by emulsification in microfluidic device

[34]

Consistency

Control the size of droplets

Low throughput

Require rapid crosslinking materials

Alginate microgel containing single MSC or pre-adipocyte cell

[35]

GelMA microparticles containing fibroblasts produced by emulsification in microfluidic device

[36]

Cell electrospinning

Fibers of Matrigel containing mouse neuroblastoma cell produced by electrospinning

[37]

Guide cell aligned

Efficient and fast nutrient exchange

Inhomogeneous cell density

Low mechanical strength

Fibers of alginate containing myoblast cells produced by cell electrospinning

[21]

Micromolding

ECM with micro vasculature structure molded by PDMS chips

[38]

Fabricate complex structure

High precision

Require precise template

Laborious

Vasculature network on 3D PDMS chips

[39]

PLGA 3D microparticles assembled in a layer-by-layer sinister process

[40]

Bioprinting

Nanofibers of peptide amphiphiles containing fibroblasts and ADCSs

[41]

Automated

Controllability

High fidelity

Damage to cells

Require printable biomaterials

Vascular conduits of gelatin and alginate produced by microfluidic bioprinting

[42]

GelMA embedded with designed vascular network of HUVECs and fibroblasts

[24]

GelMA microgels with customized size and shape

[43]

Liver models of GelMA containing hepatocytes and human stellate cells with micro channels

[44]