Table 2.

Summarized details of vascularization strategies in 3D cell culture models, starting from simplistic approaches using spheroid-based models to increasing complexities involving bioprinting-based models, to lastly, complex models utilizing microfluidic devices to recapitulate the native tissue microenvironment.

Three-Dimensional Cell Culture Model	Vascularization Approach	Highlights	References
Spheroid-based	Incorporation of collagen/fibrin hydrogels with MSC/HUVEC spheroids	Enhanced functionality due to the presence of vascularized networks	[79]
	Culturing SVF-derived cells in EGM2 using forced floating cell culture method	Presence of dense and highly organized vascular networks, showcasing morphology similar to that of in vivo vasculature	[81]
	Co-culturing β cells and ECs using magnetic levitation method	Heterogeneous distribution of cells, distinguishable CD31 expression, and significant stimulation of basal insulin secretion	[83]
	Seeding HUVECs, hTMSCs, and ADSCs on a micro-patterned hydrogel surface	Six-fold increase in CD31 expression for harvested spheroids, allowing them to be used as building blocks for constructing complex 3D microtissues	[84]
	Incorporating 2D cell monolayer of HUVECs with MG-63 spheroids cultured using hanging drop technique	Enhanced vascularization from increased VEGF expression	[85]
Bioprinting-based	Seeding MCTSs on bioprinted blood vessel layer using a cell-ladened bioink with HUVECs and LFs in GAF hydrogel	Significant vascularization and accurate anti-cancer drug treatment results; coherent with results in mice cells	[86]
	Fusing stem cells and organoids through bioprinting constraints, making them self-organizing building blocks	Ability to showcase multicellular self-organization and control over printing parameters to replicate native ECM	[87]
	Dual extrusion head bioprinter, utilizing two bioinks: parenchymal bioink 1 and non-parenchymal bioink 2	Exhibited similar physiological and metabolic properties, as well as highlighted the need of using primary cell lines for accurate modelling	[88]
	Preset extrusion bioprinting, where preset cartridge mimics the structure of a human hepatic lobule	Increased drug resistance and higher levels of albumin, MPR2, and CD31 relative to non-engineered models	[89]
	Dynamic flow-based 3D vascularized tumor model consisting of central vasculature and perfusion chamber	Significant angiogenesis and successful perfusion for a physiologically relevant drug and immunotherapy screening platform	[90]
Microfluidic-device-based	Multicellular spheroids using ECs and LFs seeded into fibrin–collagen hydrogel embedded within a microfluidic device	Showcased increased cellular migration, allowing accurate modeling and the studying of cancer metastasis to be performed	[91]
	Kidney organoid on-a-chip system involving a PDMS chip and organoids cultured in microwells under dynamic flow conditions	Cultured organoids showed increased vascularization and maturation	[92]
	Retina on-a-chip system involving a layered microfluidic chip and perfusion through connections via microchannels	First in vitro system to replicate key in vivo physiological features by showcasing interactions between photoreceptors and retinal pigment epithelium	[93]
	Bi-compartmental, monolithic heart-on-a-chip device capable of 3D carbon electrodes integration for electrical pacing	Accurate recapitulation of native cardiac tissue via electromechanical stimulations, endothelial monolayer, and selective perfusion	[94]
	Mimicking native ECM utilizing a decellularized liver ECM hydrogel in a microfluidic device	Increased drug sensitivity, and mature and functional hepatic state; high-throughput drug screening platform, and capable of multiorgan model studies	[95]