Fig. 9

Representative examples of hydrogel-mediated delivery systems for small molecules (a), peptides (b–d), and proteins (e–g). a Schematic of a hydrogel crosslinked through multiple hydrogen bonds, presenting fast shape memory to facilitate minimally invasive implantation and release of small molecule drugs for homing endogenous BMSCs to promote cartilage regeneration. Reproduced from ref. ⁵³⁵ b Schematic of a glucose-sensitive hydrogel designed for functional insulin delivery. c Insulin release profile from the gel, demonstrating a pulsatile release pattern. d Blood glucose levels of diabetic rats after subcutaneous administration. b–d reproduced from ref. ⁵⁴⁹ e Schematic of a CS hydrogel enhanced with LDH nanosheets to improve its mechanical properties and support a controlled sequential release of growth factors, promoting bone regeneration. f Release profiles of PDGF-BB and BMP-2 from the hydrogel. g Micro-computed tomography (Micro-CT) images showing skull defect repair induced by the hydrogel. e–g reproduced with permission from ref. ⁵⁷² Copyright 2022, John Wiley and Sons. Adobe Illustrator was used to generate this figure