Key biomaterial types and their roles in ECM mimicry.
| Biomaterial category | Specific examples | Key properties(biocompatibility, degradability, mechanical tunability, cell adhesion motifs) | Contribution to ECM mimicry(compositional, structural, mechanical, biochemical cues) | Advantages of in vitro models | Associated challenges |
|---|---|---|---|---|---|
| Natural polymers | Collagen, fibrin, hyaluronic acid (HA), gelatin, alginate, chitosan, silk fibroin | High biocompatibility [83], low immunogenicity [84], inherent cell adhesion sites (e.g., RGD) [67], enzymatic degradability [66]. | Compositional: mimic native ECM proteins/polysaccharides [63].Structural: form hydrogels, fibrous networks [64].Biochemical: present cell-binding motifs, sequester growth factors [76]. | Excellent biological relevance, support cell growth/differentiation, tunable properties [66]. | Variable batch-to-batch consistency, potential for immunogenicity (though low) [84], limited mechanical strength for some [85]. |
| Synthetic polymers | Polyethylene glycol (PEG), polyisocyanide (PIC), polyacrylamide (PAAm), polyvinyl alcohol (PVA) | High tunability in physical/chemical properties, controllable degradation, low immunogenicity, resistance to non-specific protein adsorption [68, 69]. | Structural: precise control over architecture, porosity.Mechanical: tunable stiffness/elasticity [73].Biochemical: functionalizable with specific cues [30]. | Greater control over properties, reduced variability, avoids animal-derived components, can be stimuli-responsive [79]. | Often lack intrinsic bioactivity/cell adhesion, may require functionalization, potential cytotoxicity from residues [86]. |
| Composite (semi-synthetic) biomaterials | Gelatin methacryloyl (GelMA), HA-PEG composites | Combines bioactivity of natural polymers with tunability/stability of synthetics; photopolymerizable, customizable mechanical properties [62, 87]. | Comprehensive mimicry (compositional, structural, mechanical, biochemical) by integrating the best features of both categories [88]. | Broad range of adjustable properties, enhanced physiological relevance, improved printability for bioprinting [89]. | Balancing properties can be complex, potential for residual toxicity from crosslinking agents, regulatory hurdles for novel combinations [70]. |
| Bioinks (specialized for 3D bioprinting) | GelMA, HAMA, alginate, recombinant spider silk proteins, cell aggregates | Tunable rheological properties (shear-thinning) [90], rapid gelation post-printing, biocompatibility, cell encapsulation capability [78]. | Enables precise spatial patterning of cells and ECM components, vascularized channels, biochemical gradients, tissue-mimetic stiffness [77, 91]. | Allows for complex, high-resolution 3D tissue constructs, high reproducibility, scalability for HTS [77]. | Cytotoxicity due to UV light/free radicals (for photopolymerizable), oxygen inhibition, long printing times, need for more relevant ECM mimics [78]. |