Table 1.

Classification of different scaffolds based on features, production techniques

Class of materials	Materials	Scaffold production	Advantages	Issues
Natural materials Similar properties to ECM, features can be modified by cross‐linking, biocompatibility and good cell attachment and proliferation	Collagen	Injectable, microbeads, sponges, hydrogels	ASC differentiation and vascularization; possible addition of growth factors, modifiable porosity	Fast degradation, low mechanical properties
	Hyaluronic acid derivatives	Hydrogels, sponges	Good differentiation of adipocytes	Expensive
	Silk	Hydrogels, disks, thin films, sponges, tubes	Good mechanical properties, low immunogenicity, possible expression of growth factors and angiogenic factors	Unknown characteristics of degradation products
	Gelatin	Hydrogels, bioprinting, sponges	Good incorporation in natural tissue, possible addition of growth factors, usable together with other scaffolds	Fast degradation, low mechanical properties
Synthetic materials Chemical and mechanical properties can be modified and have a good reproducibility	PLGA	3‐D printing, hydrogels, sponges, injectable spheres	Biodegradable	Inflammation due to degradation products; short degradation time
	PCL	3‐D printing, electrospun meshes, sponges	Suitable mechanical properties; angiogenesis in ASC‐seeded and ASC‐unseeded constructs	Degradation time not well controlled; limitation in mammary cell attachment because of hydrophobicity
	Polyurethane	Sponges	Elastic and possible good angiogenesis and adipogenesis	Issues with in vivo transplant
	Polypropylene	Meshes	Biocompatibility	Not well absorbed
	Polylactic acid	Sponges	Good mechanical properties	Degradation time too fast
	PEG	Hydrogels	Water degradable, promotion of adipose tissue regeneration	Low mechanical properties, need for cross‐linking
Biological materials Biological properties of ECM kept intact and decellularized adipose tissue leads to adipogenic differentiation without supplementation of differentiation factors	Adipose‐decellularized ECM	Bioprinting, hydrogels, injectable microparticles, 3‐D printing	ECM provides right microenvironment for cells; well‐maintained 3‐D architecture also after decellularization	Not mass‐producible; technique is difficult and time‐consuming

Note. The same production techniques can be used for more than one type of material. The pros and cons of each scaffold material are summarized (O'Halloran et al., 2017; O'Halloran et al., 2018).

Abbreviations: ASC, adipose stem cells; ECM, extracellular matrix; PCL, polycaprolactone; PEG, poly (ethylene)glycol; PLGA, polylactic‐co‐glycolic acid.