Table 1.

Common types materials used in 3D cultures, and their advantages and disadvantages.

Type of 3D Culture	Cultivation Technique/Coating Material	Production Technique	Advantages	Disadvantages	Ref.
Hydrogel based Scaffold	Collagen Sandwich, Collagen Gel/Isolated from rat tails	Gel formation by crosslinking of the water-soaked collagen–fibers	a) Containing collagen type I b) Maintenance of hepatocytes polarity including transporter activity	a) Reduced exchange of nutrients and waste products between cells and medium b) Dead cells were not removed within the matrix C) Disruption of living cells by proteases released from dead cells	[41]
	Matrigel/ECM proteins extracted from mice Englebreth-Holm-Swarm tumors	Cold Matrigel is mixed with medium and plated between 2 and 6 °C as fluid solution. Temperatures ≥ 10 °C results in a solid gel formation	a) Cell polarity preserved b) Containing various ECM proteins and growth factors c) Promotion of cell differentiation	a) The same disadvantages as described for collagen b) The components of the Matrigel are not well defined	[42,43]
Scaffold	Decellularized Human Liver as a Natural Scaffold	Tissue was decellularized, remaining ECM was used as scaffold for culture	a) Perfectly represents the structural features as well as the biochemical components of the human liver matrix	a) Elaborate production b) Limited availability of donor tissue	[44]
	Cryogel/PHEMA, Bis-Acrylamide, Alginate, Gelatin, Collagen	Monomers are frozen in aqueous solution with crosslinking agents. Ice crystals form, which remains after polymerization and thawing as pores in the scaffold matrix	a) Simple preparation b) Create various pore sizes and stiffness	a) Difficult standardization of the manufacturing process b) Variation in scaffold parameters possible only in certain range	[27,29]
	Electrospinning/Natural or synthetic polymer solutions	electrostatic fiber formation which utilizes electrical forces to produce polymer fibers	a) Relatively high standardizable b) Using different materials c) Using different fiber strengths and degrees of intertwining adjustable	a) Generating solid tissue structure during electrospinning intertwined fibers	[28,45]
	3D printing/Natural products like gelatin and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) for crosslinking	Scaffold was printed by using a 3D printer	a) Uniform and reproducible b) Reduction of user error c) Precisely adjustable scaffold pore size d) interconnectivity and controlled geometry	a) Requires elaborated equipment b) High standardization results in lacking of representation of the biological variability c) Generating pores with many different sizes is difficult	[46]

ECM: extracellular matrix. PHEMA: Poly 2-hydroxyethyl methacrylate.