Biological scaffold as potential platforms for stem cells: Current development and applications in wound healing

Table 1 Characteristics of biopolymers and their biological role in healing process

Biopolymer	Sources	Function and characteristics in wound healing	Merits	Demerits	Ref.
Cellulose	Specific bacterial strains	Keep a moist environment. Absorb the exudates. Blocking bacterial infiltration	High purity. Good mechanical properties. Porous structure. High hydrophilic properties	No antimicrobial. Slow biodegradability	[26-31]
	Plants (main sources: Cotton and woods)	Support tissue regeneration. Enhances cell attachment and proliferation	Good mechanical properties. Porous structure	Impurities available. Low solubility. No antimicrobial. Slow biodegradability	[22-26]
Alginates	Brown marine algae and bacteria	Keep a moist environment. Absorb the exudates. Converted into a gel to cover the wound surface	Haemostatic. Form a hydrogel network on the surface of the wound	Poor mechanical properties. Tendency to swell. Not suitable for dry wounds	[37-42]
Hyaluronic acid	Animal origin	Good biocompatibility. Promote keratinocyte migration. Promote fibroblasts proliferation. Promote angiogenesis	Flexible. Highly biocompatible	Low mechanical strength. Low solubility	[45-48]
Chitosan	Exoskeleton of crabs, insects, fungal cell wall	Antibacterial properties. Hemostasis effect	Antimicrobial. Haemostatic	Low strength and toughness. Low solubility in aqueous solutions	[49-55]
Collagen	Bovine, porcine etc.	Keep a moist environment. Promote cell migration, proliferation, differentiation and angiogenesis. Regulate growth factors and cytokines	Cost effective. High water holding capacity	Has a risk of allergies. Exhibits restricted solubility in water	[58-65]
Gelatin	Extracted from the collagen	Keep a moist environment. Promote cell adhesion	Cost effective. High water holding capacity	Has a risk of allergies. Exhibits low solubility in cold water. Susceptible to losing structural stability at elevated temperatures	[66-72]
Silk fibroin	Silkworm cocoons	Excellent mechanical strength and flexibility. Enhances cell adhesion, migration, and proliferation	Good mechanical strength and flexibility. Good biocompatibility	Complex extraction and processing	[73-78]
Fibrous protein	Plasma	Keep a moist environment. Promotes cell growth and adhesion	Can be injected and polymerizes in situ. Can be functionalized into the fibrinogen or thrombin component in the fibrin formulation	Complex extraction and processing	[79-85]

Table 2 Mesenchymal stem cells and their application in wound healing

MSCs	Sources	Application in wound healing
ADSCs	Adipose	Zhou et al[115] demonstrated the systemic administration of ADSCs and ADSC-exosomes effectively stimulated cell proliferation, suppressed cell apoptosis and inflammation, and improved skin elasticity and barrier integrity. Zheng et al[116] unveiled the protective effects of ADSC-exosomes on cells against oxidative damage. These exosomes enhanced cell proliferation and migration while reducing apoptosis
BMSCs	Bone marrow	Ding et al[119] preconditioned BMSC-exosomes with deferoxamine exhibited heightened proangiogenic. Gondaliya et al[120] explored the combination of a miR-155 inhibitor with BMSC-exosomes, showcased augmented keratinocyte migration, restoration of FGF-7 levels, and decreased inflammation
hUC-MSCs	Umbilical cord tissue	Zhang et al[122] devised a scaffold to generate tissue sheets using hUC-MSCs which significantly expedited wound healing. Xue et al[123] engineered spherical hUC-MSCs, which were subsequently integrated into self-assembling hydrogels
EPSCs	Epidermis	Pan et al[125] devised an electrospun micro/nanofiber scaffold to culture and transplant EPSCs with the aim of preserving their stemness and preventing differentiation
FD-MSCs	Fetal dermal	Costa et al[127] found out the exosomes from FD-MSCs effectively stimulated adult dermal fibroblasts’ proliferation, migration and secretion
hAFSCs	Human amniotic fluid	Zhang et al[129] showed that hAFSC-exosomes expedited wound healing, promoting hair follicle, nerve, and vessel regeneration

ADSCs: Adipose-derived mesenchymal stem cells; BMSCs: Bone marrow-derived mesenchymal stem cells; hUC-MSCs: Human umbilical cord-derived mesenchymal stem cells; EPSCs: Epidermal stem cells; FD-MSCs: Fetal dermal mesenchymal stem cells; hAFSCs: Human amniotic fluid-derived stem cells; FGF: Fibroblast growth factor.