Yuhang Huang, Eugenia Kumacheva
Hydrogels with multiple characteristic pore dimensions (HMPs) have emerged as a powerful class of soft materials inspired by biological systems. By incorporating distinct average pore sizes into a single network, simultaneous control over competing hydrogel transport properties can be achieved, including throughput and selectivity, both of which are important in drug delivery, tissue engineering, catalysis, sensing, and water remediation hydrogel applications. This review highlights recent advances in the design, synthesis, characterization, and applications of HMPs. It highlights the fundamental principles of transport in these hydrogels, including the role of spatial arrangement of regions with different pore dimensions in probe mobility and fluid flow. Experimental and theoretical characterization of distinct pore dimensions in HMPs is followed by the discussion of the contribution of multiple pore dimensions to HMP functionality. The review provides the summary of the strategies for fabricating HMPs and their applications. An outlook highlights key challenges and future opportunities in this field to advance HMPs as the new generation of hydrogel-based materials for diverse applications.