A click chemistry-mediated all-peptide cell printing hydrogel platform for diabetic wound healing

Article https://doi.org/10.1038/s41467-023-43364-2 A click chemistry-mediated all-peptide cell printing hydrogel platform for diabetic wound healing Received: 2 April 2023 Check for updates 1234567890():,; 1234567890():,; Accepted: 8 November 2023 Jinjian Huang1,7, Rong Yang2,3,7, Jiao Jiao4,7, Ze Li1, Penghui Wang2, Ye Liu5, Sicheng Li1, Canwen Chen1, Zongan Li6, Guiwen Qu5, Kang Chen1, Xiuwen Wu 1 , Bo Chi 2 & Jianan Ren 1 High glucose-induced vascular endothelial injury is a major pathological factor involved in non-healing diabetic wounds. To interrupt this pathological process, we design an all-peptide printable hydrogel platform based on highly efficient and precise one-step click chemistry of thiolated γ-polyglutamic acid, glycidyl methacrylate-conjugated γ-polyglutamic acid, and thiolated arginineglycine-aspartate sequences. Vascular endothelial growth factor 165overexpressed human umbilical vein endothelial cells are printed using this platform, hence fabricating a living material with high cell viability and precise cell spatial distribution control. This cell-laden hydrogel platform accelerates the diabetic wound healing of rats based on the unabated vascular endothelial growth factor 165 release, which promotes angiogenesis and alleviates damages on vascular endothelial mitochondria, thereby reducing tissue hypoxia, downregulating inflammation, and facilitating extracellular matrix remodeling. Together, this study offers a promising strategy for fabricating tissue-friendly, high-efficient, and accurate 3D printed all-peptide hydrogel platform for cell delivery and self-renewable growth factor therapy. Diabetes mellitus (DM) is a chronic metabolic disorder that affects almost 463 million adults worldwide. Its incidence is continuously growing due to increasing population age1. Approximately a quarter of DM patients develop diabetic foot ulcers (DFUs), with a five-year mortality rate of 30.5%, which is similar to that of cancer (31%)2. DFUs are associated with chronic pain, decreased self-care abilities, prolonged infections, high risk of foot amputation, and heavy economic burdens of roughly US$ 8.5 billion globally3. Conservative medical treatments, such as off-loading therapy, negative pressure therapy, surgical debridement, and antibiotics, often do not achieve satisfactory outcomes and are associated with adverse effects4,5. Therefore, efforts to develop new therapies for such complicated and chronic wounds are required. The process of wound healing includes three overlapping and dynamic phases of inflammation, proliferation, and tissue remodeling6. Throughout the entire process, angiogenesis plays fundamental roles by facilitating immune cell migration, increasing nutrition and oxygen supply, and modulating scar formation7,8. Unlike non-diabetic wounds, the initiation of angiogenesis is impaired in diabetic wounds due to high glucose (HG)-induced endothelial cell 1 Research Institute of General Surgery, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210093, China. 2State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China. 3Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai 200032, China. 4 Department of Rehabilitation, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China. 5School of Medicine, Southeast University, Nanjing 210009, China. 6Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, NARI School of Electrical and Automation Engineering, Nanjing e-mail: ; Normal University, Nanjing 210042, China. 7These authors contributed equally: Jinjian Huang, Rong Yang, Jiao Jiao. ; Nature Communications | (2023)14:7856 1 Article damage and organelle dysfunction9–11. The resultant poor vascularization of wounds leads to tissue hypoxia and triggers the activation of hypoxia-elicited inflammation cascade12,13, consequently impeding the wound-healing process. Thus, the angiogenic function is a major target of new therapies for diabetic wound healing. In recent years, growth factors, such as vascular endothelial growth factor (VEGF), have shown promising results regarding improving diabetic wound healing14. VEGF has different actions depending on the VEGF receptor (VEGFR) that is stimulated. VEGFR-1 mainly promotes inflammation, while VEGFR-2 contributes to angiogenesis15. A higher expression of VEGF is associated with improved outcomes of DFUs16. However, a meta-analysis on clinical trials of growth factors revealed that the efficacy of growth factors for diabetic wound healing remains questionable and varies with their category, usage, and frequency17. This is partially due to the inability of growth factors to stimulate wound healing because they are diluted and flushed away by wound exudation or inactivated with time due to hydrolysis by tissue proteases18,19. Moreover, diabetic wound care consumes longer time and is a great nursing load to appropriately care for the dressings that contain growth factors20. These dressings supplement the wounds with the required growth factors. Several previous studies have reported on different growth factor delivery systems that can prolong the release time21,22, have smart releasing profiles23, or increase protein stability24. These systems were based on intelligent hydrogels, polymeric fibers, microspheres, microbubbles, diverse nanoparticles, liposomes, and other hybrid materials25–27, which have enhanced therapeutic effects on tissue repair. However, concerns still exist regarding the dose attenuation or inactivation of growth factors during prolonged periods of diabetic wound healing since the growth factors are not self-supplemented. The use of cellular vehicles to release therapeutic agents has recently offered the prospect of biocompatibility, large-loading capacity, and long in vivo lifespan28. Still, to replenish diabetic wounds with continuous and self-renewable VEGF was rarely explored and challenging. Moreover, in case of urgent needs for complicated wounds, the majority of drug carriers are not able to present customized shapes29, thus creating gaps between bench and bedside. Hence, it is critical to develop delivery systems that can achieve shape-adaptation promptly and produce growth factors continuously for wounds to accelerate healing. Digital light processing (DLP) printing is a high-resolution fastspeed additive manufacturing technology that forms desirable 3D structures through photopolymerization reaction to solidify hydrogels30, which has been considered a type of promising biomaterial effective for wound healing31–34. Some traditional peptide-based hydrogel bioinks have been developed for cell-based photocuring printing such as methacrylate gelatin35, methacrylate silk36, and methacrylate decellularized extracellular matrix37. The photoc (...truncated)