Porosity parameters are one of the structural properties of the extracellular microenvironment that have been shown to have a great impact on the cellular phenotype and various biological activities such as diffusion of fluid,initial protein adsorption,permeability,cell penetration and migration,ECM deposition,angiogenesis,and rate and pattern of new tissue formation.The heterogeneity of the study protocols and research methodologies do not allow reliable meta-analysis for definite findings.As such,despite the huge available literature,no generally accepted consensus is defined for the porosity requirements of specific tissue engineering applications.However,based on the biomimetic approach,the biological substitutes should replicate the 3D local micro-environment of the recipient site with matching porosity parameters to best support local cells during tissue regeneration.Ideally,the porosity of biomaterials should mimic the porosity of the substituting natural tissue and match the clinical requirements.Careful analysis of the impact of architectures (i.e.,porosity) on biophysical,biochemical,and biological behaviors will support designing smart biomaterials with customized architectural and functional properties that are patient and defect site-specific.