Self-assembling Peptide Hydrogels Research Articles

A novel peptide hydrogel of metal ion clusters for accelerating bone defect regeneration.

In the absence of adequate treatment, effective bone regeneration remains a great challenge. Exploring hydrogels with properties of excellent bioactivity, stability, non-immunogenicity, and commercialization is an important step to develop hydrogel-based bone regeneration materials. In this study, we engineered a self-assembled chelating peptide hydrogel loaded with an osteogenic metal ion cluster extracted from the processed pyritum decoction, including Fe2+, Cu2+, Zn2+, Mn2+, Mg2+, and Ca2+ ions, named processed pyritum hydrogel (PPH). We demonstrated that as a reservoir of beneficial metal ion clusters in bone regeneration, PPH has been shown to regulate a variety of genes in the process of bone regeneration. These genes are mainly involved in extracellular matrix synthesis, cell adhesion and migration, cytokine expression, antimicrobial and inflammation. Therefore, PPH accelerated the progress of various bone healing stages, and shortened the bone healing cycle by 4weeks. Our investigation outcomes showed that the engineered metal ion cluster hydrogel is a novel, simple, and commercializable bone-regenerating hydrogel with potential clinical use.

Nitric oxide-generating self-assembling peptide hydrogel coating for enhancing hemocompatibility of blood-contacting devices

Thrombosis is the major stumbling block to the clinical application of blood-contacting devices. Herein, a quick and easy surface engineering strategy of hydrogel coating with the therapeutic gas nitric oxide (NO) generation was reported to realize up-regulation of cyclic guanosine monophosphate (cGMP) and improve hemocompatibility for diverse metal materials. We first introduce the active centre selenocysteine of glutathione peroxidase (GPx) to the self-assembling peptide (RADA)4, obtaining a functionalized hydrogel. Then the hydrogel is directly coated on the 316L stainless steel (SS) for catalytically generating NO from endogenous s-nitrosothiols (RSNO). The generated NO endows the coated surface with regulation of platelet behavior and reduction of plasmatic coagulation activation and complement system activation, hence improving antithrombotic ability in vitro and ex vivo. Overall, our NO-generating hydrogel coating surface engineering strategy provides a novel solution to remove the obstacle about thrombosis of blood-contacting devices in clinic.

Remodeling Microenvironment for Endogenous Repair through Precise Modulation of Chondroitin Sulfate Proteoglycans Following Spinal Cord Injury.

The fluid-filled cystic cavity sealed by a dense scar developed following traumatic spinal cord injury (SCI) has been a major obstacle to neural regeneration and functional recovery. Here the transected lesion is bridged using a functional self-assembling peptide (F-SAP) hydrogel loaded with membrane-permeable intracellular sigma peptide (ISP) and intracellular LAR peptide (ILP), targeted at perturbing chondroitin sulfate proteoglycan (CSPG) inhibitory signaling. As compared to F-SAP hydrogel loaded with chondroitinase ABC, the F-SAP+ISP/ILP promotes a beneficial anti-inflammatory response via manipulation of microglia/macrophages infiltration and assembly of extracellular matrix (ECM) molecules into fibrotic matrix rather than scarring tissues. The remodeled ECM creates a permissive environment that supports axon regrowth and the formation of synaptic connections with neurons derived from endogenous neural stem cells. The remodeled networks contribute to functional recovery, as demonstrated by improved hind limb movements and electrophysiological properties. This work proposes a unique mechanism that ECM remodeling induced by CSPG-manipulation-based anti-inflammation can construct a permissive environment for neural regeneration, and shed light on the advancement of manipulation of cascading cellular and molecular events potential for endogenous repair of SCI.

Self-Assembled Peptide Hydrogel for Accelerated Wound Healing: Impact of N-Terminal and C-Terminal Modifications.

Wound dressings are required to provide a moist environment for wounds, protect against invading infections, expedite tissue regeneration, and improve wound healing efficiency. Developing biomaterials with all aforesaid properties is still a big challenge. However, peptide-based hydrogels have the potential to overcome these challenges as they are biocompatible, biodegradable as well as have the ability to mimic the extracellular matrix and provide an appropriate moist environment which is important for wound healing. With this in mind, we report the preparation and comparison of three hexapeptide-based hydrogels, LIVAGD, with the aim to understand the importance of the N-terminal protecting group as well as the C-terminal amino acid substitution on its various biological efficacies. Fmoc and acetyl groups were used for N-terminal peptide protection, while aspartic acid was substituted with lysine at the C-terminus. The resulting peptide-based hydrogels were compared. Fmoc peptide-based hydrogels exhibited efficient anti-inflammatory action along with improved biocompatibility while lysine provided enhanced antibacterial effect to the hydrogel. Additionally, in vivo efficacy was examined using a mouse model, and Fmoc hydrogels demonstrated an improved wound healing ability with ∼40 % faster healing rate in comparison to the reported acetylated peptide hydrogels.

Self-assembling RADA16 peptide hydrogel supports hemostasis, synechiae reduction, and wound healing in a sheep model of endoscopic nasal surgery

ObjectivesComplications of endoscopic sinus/nasal turbinate surgery include postoperative hemorrhage, synechiae formation, and poor wound healing. Our primary objectives were to evaluate whether a topical hydrogel based on self-assembling RADA16 peptides: i) reduces bleeding and synechiae formation, and ii) supports wound healing, using a sheep nasal surgery model. MethodsThirty sheep received endoscopic surgery-created bilateral nasal mucosal injuries on the middle turbinate/opposing septum. Injuries were randomly assigned RADA16, Gelatin-thrombin, or no treatment. Outcomes included intra-operative hemostasis, scar tissue/synechiae formation and wound healing at 2 weeks and the 6-week study terminus, and histopathology. ResultsIntra-operative hemostasis time improved with RADA16 and Gelatin-thrombin versus Control wounds (139.7±56.2 s, 145.4±58.1 s, and 224.0±69.9 s, respectively; p < 0.0001 for both comparisons). Two-week synechiae scores (maximum 4 points) were similar in Controls (2.9±1.8 points) and Gelatin-thrombin (3.1±1.6 points) wounds (p > 0.05), but were reduced in RADA16 sites by 91% versus Controls and 92% versus Gelatin-thrombin treatment (0.3±0.6 points; p < 0.0001 for both comparisons). Six-week synechiae scores were similar in Control (1.1±1.7 points) and Gelatin-thrombin (1.7±2.0 points) wounds (p > 0.05), but reduced 100% in RADA16-treated wounds. Synechiae occurred in fewer RADA16-treated sites at 2 weeks (20%) versus Gelatin-thrombin (80%) and Controls (75%; p < 0.01) and at 6 weeks (0%, 50% and 35%, respectively; p < 0.01). RADA16 was associated with significantly lower 6-week histopathology scores, driven by reduced submucosal fibrosis and angiogenesis. ConclusionAlthough RADA16 and Gelatin-thrombin similarly accelerated hemostasis in this sheep endoscopic sinus surgery model, only RADA16 reduced postoperative synechiae formation at 2 weeks with an absence of synechiae at 6 weeks. Histology suggested RADA16 enhanced mucosal regeneration.

Research progress of self-assembling peptide hydrogels in repairing cartilage defects

Due to the lack of blood vessels, nerves and lymphatic vessels, the capacity of articular cartilage to heal is extremely limited. Once damaged, it is urgent for articular cartilage to repair the injury. In recent years, there has been an increase in cartilage tissue engineering studies. Self-assembling peptide hydrogel as a kind of hydrogels composed of peptides and water is widely used in cartilage tissue engineering. Under noncovalent interactions such as electrostatic interaction, hydrophobic interaction, hydrogen bonding and pi-pi stacking force, peptides self-assemble into three-dimensional (3D) structures that mimic the natural extracellular matrix and allow cells to grow, proliferate and differentiate. Because SAPHs have excellent biocompatibility and biodegradability, variable mechanical properties, low immunogenicity, injectability, and the ability to load cells and bioactive substances, many researchers utilized them to promote the repair and regeneration of articular cartilage after damage. Therefore, the purpose of this review is to sum up the composition, injury characteristics, and treatments of articular cartilage, as well as the action of SAPHs in repairing articular cartilage damage.

Click chemistry functionalization of self-assembling peptide hydrogels.

Self-assembling peptide (SAP) hydrogels provide a fibrous microenvironment to cells while also giving users control of biochemical and mechanical cues. Previously, biochemical cues were introduced by physically mixing them with SAPs prior to hydrogel assembly, or by incorporating them into the SAP sequence during peptide synthesis, which limited flexibility and increased costs. To circumvent these limitations, we developed "Click SAPs," a novel formulation that can be easily functionalized via click chemistry thiol-ene reaction. Due to its high cytocompatibility, the thiol-ene click reaction is currently used to crosslink and functionalize other types of polymeric hydrogels. In this study, we developed a click chemistry compatible SAP platform by addition of a modified lysine (lysine-alloc) to the SAP sequence, enabling effective coupling of thiol-containing molecules to the SAP hydrogel network. We demonstrate the flexibility of this approach by incorporating a fluorescent dye, a cellular adhesion peptide, and a matrix metalloproteinase-sensitive biosensor using the thiol-ene reaction in 3D Click SAPs. Using atomic force microscopy, we demonstrate that Click SAPs retain the ability to self-assemble into fibers, similar to previous systems. Additionally, a range of physiologically relevant stiffnesses can be achieved by adjusting SAP concentration. Encapsulated cells maintain high viability in Click SAPs and can interact with adhesion peptides and a matrix metalloproteinase biosensor, demonstrating that incorporated molecules retain their biological activity. The Click SAP platform supports easier functionalization with a wider array of bioactive molecules and enables new investigations with temporal and spatial control of the cellular microenvironment.

Enhanced Proliferation of Human Mesenchymal Stem Cells by Self-Assembled Peptide Hydrogel Modified with Heparin Mimetic Peptide

The development of three-dimensional (3D) microenvironments that mimic the role of native extracellular matrix (ECM) components is very crucial. Self-assembling peptide (SAP) hydrogels have been utilized as scaffolds for encapsulation, 3D culture, proliferation, and differentiation of cells and also for repairing defects in cartilage tissue. SAPs can be biofunctionalized with short peptide epitopes to form biomimetic scaffolds. Herein, KLD (KLDLKLDLKLDL) SAP was functionalized with a short bioactive motif, EGDK, to fabricate KLD-HM (KLDLKLDLKLDL-EGDK) SAP hydrogel and self-assembled. In this study, it was aimed to investigate the effect of developed KLD-HM SAP hydrogels on the viability and proliferation of human mesenchymal stem cells (hMSCs). For ensuring the stability of SAPs, the rheological properties and degradation profile of produced SAP hydrogels were assessed. After the encapsulation of hMSCs in SAP hydrogels, MTT assay and Live and Dead staining assay were conducted. We showed that these biomimetic peptide hydrogel scaffolds provided a proper microenvironment for encapsulated hMSCs and the developed SAP hydrogels promoted the adhesion, viability, and proliferation of hMSCs. Our results suggest that designed bioactive SAP hydrogel scaffolds might be useful for promoting the regeneration of cartilage tissue.

Growth and differentiation of human induced pluripotent stem cell (hiPSC)-derived kidney organoids using fully synthetic peptide hydrogels

Human induced pluripotent stem cell (hiPSC)-derived kidney organoids have prospective applications ranging from basic disease modelling to personalised medicine. However, there remains a necessity to refine the biophysical and biochemical parameters that govern kidney organoid formation. Differentiation within fully-controllable and physiologically relevant 3D growth environments will be critical to improving organoid reproducibility and maturation. Here, we matured hiPSC-derived kidney organoids within fully synthetic self-assembling peptide hydrogels (SAPHs) of variable stiffness (storage modulus, G′). The resulting organoids contained complex structures comparable to those differentiated within the animal-derived matrix, Matrigel. Single-cell RNA sequencing (scRNA-seq) was then used to compare organoids matured within SAPHs to those grown within Matrigel or at the air-liquid interface. A total of 13,179 cells were analysed, revealing 14 distinct clusters. Organoid compositional analysis revealed a larger proportion of nephron cell types within Transwell-derived organoids, while SAPH-derived organoids were enriched for stromal-associated cell populations. Notably, differentiation within a higher G’ SAPH generated podocytes with more mature gene expression profiles. Additionally, maturation within a 3D microenvironment significantly reduced the derivation of off-target cell types, which are a known limitation of current kidney organoid protocols. This work demonstrates the utility of synthetic peptide-based hydrogels with a defined stiffness, as a minimally complex microenvironment for the selected differentiation of kidney organoids.

Comparison of PuraStat self-assembling peptide hydrogel versus mineral-based Hemospray for endoscopic hemostasis of upper and lower gastrointestinal lesions in pigs

ObjectiveTo compare a RADA16-based self-assembling peptide hydrogel versus an inorganic powder-based spray device for controlling postoperative bleeding in upper and lower GI mucosal lesions in pigs.MethodsMultiple mucosal lesions were endoscopically-created in the stomachs and lower colons of six Yorkshire swine on Day 0. Three animals’ wounds were treated with 2.5% RADA16 solution (PuraStat®), two animals were treated with an aerosolized mineral powder (Hemospray®), and one animal was an untreated control. Primary outcomes were test article applications required to control initial bleeding, time-to-hemostasis, and rebleeding incidence. Secondary outcomes included animal recovery, and clinical pathology at weekly endoscopic evaluations and the 4-week study terminus.ResultsNumber of material administrations required and time-to-hemostasis was comparable between PuraStat and Hemospray groups. Rebleeding rates were comparable between treatments. Two of 12 (17%) Hemospray and none of 18 (0%) PuraStat stomach sites experienced rebleeding during the final 4 min of the 10-min observation period. No delayed bleeding was observed during weekly endoscopic follow-ups. Hematology and serology values remained normal in all animals. Histology showed expected healing responses at all PuraStat- and Hemospray-treated defects, with less inflammation than untreated sites. Histomorphological observations were comparable between different groups for both the stomach and colon for test and control materials, with lower inflammation scores than untreated sites. Performance and usability responses were generally good with both systems, although the Ability to Treat Intended Site score was significantly better with PuraStat in upper GI lesions.ConclusionsPuraStat and Hemospray were effective topical hemostats for mild-to-moderate bleeding in upper and lower GI wounds. Rebleeding was observed in two of 12 Hemospray-treated sites and none of 18 PuraStat-treated sites. PuraStat and Hemospray were associated with better wound healing than untreated controls. The ability to treat upper GI lesions was easier with the PuraStat versus Hemospray system.

The RGD-modified self-assembling D-form peptide hydrogel enhances the therapeutic effects of mesenchymal stem cells (MSC) for hindlimb ischemia by promoting angiogenesis

Mesenchymal stem cell (MSC)-based therapy was an ideal strategy for therapeutic angiogenesis in ischemic tissues. However, limitations such as heterogeneous proangiogenic nature and low cell survival following transplantation is a key challenge for clinical applications. Biofunctional materials such as extracellular matrix (ECM) and hydrogels are considered with great promise for improved therapeutics by constructing a supportable 3D microenvironment niche for transplanted cells. Here, we employ the RGD (Arg-Gly-Asp)-modified self-assembling D-form peptide hydrogel (Nap-DFDFKGRGD) to serve as the co-transplantation platform for human placental MSCs (hP-MSCs). Our data showed that this D-form hydrogel possessed excellent biocompatibility and biostability, exerting an anti-apoptosis capacity and improved cell viability in vitro. Furthermore, we found that the self-assembled hydrogel improved cell survival, as well as promoted collateral vessel revascularization by bioluminescence imaging (BLI) and micro-CT imaging analysis. Further study confirmed significant up-regulation of proangiogenic cytokines of hP-MSCs in vivo. These results demonstrated the improvements of therapeutic efficacy of hP-MSCs in terms of tissue regeneration and functional recovery in the murine hindlimb ischemia (HLI) model. In conclusion, the strategy provided a promising option for ischemia diseases by improving the proangiogenic effects of MSCs and further for enhancing the therapeutic efficiency of MSCs with the RGD motif and the D-form peptide hydrogel.

Use of a novel self-assembling hemostatic gel as a complementary therapeutic tool for endoscopic sphincterotomy-related bleeding.

PuraStat is a novel self-assembling peptide hydrogel developed as a hemostatic agent for endoscopic and surgical procedures which can be applied to bleeding from various lesions of the gastrointestinal tract. Yamamoto and colleagues present a video showing the actual endoscopic hemostasis using PuraStat for endoscopic sphincterotomy-related bleeding.

Polyaniline Functionalized Peptide Self-Assembled Conductive Hydrogel for 3D Cell Culture.

The functionalization of self-assembled peptide hydrogel is of great importance to broaden its applications in the field of biomedicine. In this work, conductive hydrogel is fabricated by introducing conductive polymer polyaniline into peptide self-assembled hydrogel. Compared with pure peptide formed hydrogel, the conductive hydrogel exhibits enhanced conductivity, mechanical property and stability. In addition, the hydrogel is tested to be of great injectability and 3D bio-printability and could support the viability of encapsulated cells that are sensitive to electrical signals. It should have great application prospects in the preparation of tissue engineering scaffolds.

Sequence-Selected C13-Dipeptide Self-Assembled Hydrogels for Encapsulation of Lemon Essential Oil with Antibacterial Activity.

Supramolecular self-assembling peptide hydrogels are attracting attention. The switching of even one amino acid may lead to differences in structure and functions of peptide hydrogels. Herein, we investigate the effect of substitution of a single amino acid residue on the gelation properties of C13-dipeptide hydrogels. We show that four C13-R1Y (C13-VY, C13-FY, C13-WY, and C13-YY) can form hydrogels with drastically tunable rigidity (the G' values were 5.74, 0.16, 27.74, and 67.90 KPa, respectively). Moreover, C13-WY and C13-YY hydrogels with high stability and excellent mechanical properties formed β-sheet nanofiber cross-linked networks. Furthermore, we applied four hydrogels into encapsulation of lemon essential oil (LEO). The peptide hydrogels had a high encapsulation rate and slowly released the LEO. Importantly, the LEO-loaded hydrogels showed enhanced antibacterial activity than free LEO. Our results clearly demonstrate the significance of side-chain interactions in determining hydrogel properties and their potential application in encapsulation for nutrition agents and hydrophobic drugs.

Advantages of Self-assembled Nano Peptide Hydrogels in Biological Tissue Engineering.

With the development of tissue engineering research, biological scaffolds have been widely studied and applied in the field of regenerative medicine. Self-assembling nanopeptide hydrogels have good biocompatibility, and their seed cells can be used for their biological activities and have no toxic side effects. The products can be absorbed and degraded by the organism and have great advantages in tissue engineering and regenerative medicine. Studies have shown that the self-assembled nano peptide hydrogel and adipose-derived mesenchymal stem cells (ADMSCs) mixed solution are "biological ink". 3D related biological printing technology can be used to print related tissue models and induce ADMSCs to differentiate into blood vessels. It is further illustrated that the use of self-assembled nano peptide hydrogel scaffolds to load stem cells has a good application prospect in stem cell transplantation and 3D biological printing.

Growth and differentiation of human induced pluripotent stem cell (hiPSC) derived kidney organoids using fully synthetic peptide hydrogels

Human induced pluripotent stem cell (hiPSC)‐derived kidney organoids have prospective applications ranging from basic disease modelling to personalised medicine. However, there remains a necessity to refine the biophysical and biochemical parameters that govern kidney organoid formation. Differentiation within fully‐controllable and physiologically relevant 3D growth environments will be critical to improving organoid reproducibility and maturation. Here, we matured hiPSC‐derived kidney organoids within fully synthetic self‐assembling peptide hydrogels (SAPHs) of variable stiffness (storage modulus, G′). The resulting organoids contained complex structures comparable to those differentiated within the animal‐derived matrix, Matrigel. Single‐cell RNA sequencing (scRNA‐seq) was then used to compare organoids matured within SAPHs to those grown within Matrigel or at the air‐liquid interface. A total of 13,179 cells were analysed, revealing 14 distinct clusters. Organoid compositional analysis revealed a larger proportion of nephron cell types within Transwell‐derived organoids, while SAPH derived organoids were enriched for stromal‐associated cell populations. Notably, differentiation within a higher G’ SAPH generated podocytes with more mature gene expression profiles. Additionally, maturation within a 3D microenvironment significantly reduced the derivation of offtarget cell types, which are a known limitation of current kidney organoid protocols. This work demonstrates the utility of synthetic peptide‐based hydrogels with a defined stiffness, as a minimally complex microenvironment for the selected differentiation of kidney organoids.

Extracellular Matrix Biomimetic Hydrogels, Encapsulated with Stromal Cell-Derived Factor 1, Improve the Composition of Foetal Tissue Grafts in a Rodent Model of Parkinson's Disease.

Clinical studies have provided evidence for dopamine (DA) cell replacement therapy in Parkinson’s Disease. However, grafts derived from foetal tissue or pluripotent stem cells (PSCs) remain heterogeneous, with a high proportion of non-dopaminergic cells, and display subthreshold reinnervation of target tissues, thereby highlighting the need to identify new strategies to improve graft outcomes. In recent work, Stromal Cell-Derived Factor-1 (SDF1), secreted from meninges, has been shown to exert many roles during ventral midbrain DA development and DA-directed differentiation of PSCs. Related, co-implantation of meningeal cells has been shown to improve neural graft outcomes, however, no direct evidence for the role of SDF1 in neural grafting has been shown. Due to the rapid degradation of SDF1 protein, here, we utilised a hydrogel to entrap the protein and sustain its delivery at the transplant site to assess the impact on DA progenitor differentiation, survival and plasticity. Hydrogels were fabricated from self-assembling peptides (SAP), presenting an epitope for laminin, the brain’s main extracellular matrix protein, thereby providing cell adhesive support for the grafts and additional laminin–integrin signalling to influence cell fate. We show that SDF1 functionalised SAP hydrogels resulted in larger grafts, containing more DA neurons, increased A9 DA specification (the subpopulation of DA neurons responsible for motor function) and enhanced innervation. These findings demonstrate the capacity for functionalised, tissue-specific hydrogels to improve the composition of grafts targeted for neural repair.

Incorporation of Natural and Recombinant Collagen Proteins within Fmoc-Based Self-Assembling Peptide Hydrogels.

Hydrogel biomaterials mimic the natural extracellular matrix through their nanofibrous ultrastructure and composition and provide an appropriate environment for cell–matrix and cell–cell interactions within their polymeric network. Hydrogels can be modified with different proteins, cytokines, or cell-adhesion motifs to control cell behavior and cell differentiation. Collagens are desirable and versatile proteins for hydrogel modification due to their abundance in the vertebrate extracellular matrix and their interactions with cell-surface receptors. Here, we report a quick, inexpensive and effective protocol for incorporation of natural, synthetic and recombinant collagens into Fmoc-based self-assembling peptide hydrogels. The hydrogels are modified through a diffusion protocol in which collagen molecules of different molecular sizes are successfully incorporated and retained over time. Characterization studies show that these collagens interact with the hydrogel fibers without affecting the overall mechanical properties of the composite hydrogels. Furthermore, the collagen molecules incorporated into the hydrogels are still biologically active and provide sites for adhesion and spreading of human fibrosarcoma cells through interaction with the α2β1 integrin. Our protocol can be used to incorporate different types of collagen molecules into peptide-based hydrogels without any prior chemical modification. These modified hydrogels could be used in studies where collagen-based substrates are required to differentiate and control the cell behavior. Our protocol can be easily adapted to the incorporation of other bioactive proteins and peptides into peptide-based hydrogels to modulate their characteristics and their interaction with different cell types.

An amelogenin-based peptide hydrogel promoted the odontogenic differentiation of human dental pulp cells

Amelogenin can induce odontogenic differentiation of human dental pulp cells (HDPCs), which has great potential and advantages in dentine-pulp complex regeneration. However, the unstability of amelogenin limits its further application. This study constructed amelogenin self-assembling peptide hydrogels (L-gel or D-gel) by heating-cooling technique, investigated the effects of these hydrogels on the odontogenic differentiation of HDPCs and explored the underneath mechanism. The critical aggregation concentration, conformation, morphology, mechanical property and biological stability of the hydrogels were characterized, respectively. The effects of the hydrogels on the odontogenic differentiation of HDPCs were evaluated via alkaline phosphatase activity measurement, quantitative reverse transcription polymerase chain reaction, western blot, Alizarin red staining and scanning electron microscope. The mechanism was explored via signaling pathway experiments. Results showed that both the L-gel and D-gel stimulated the odontogenic differentiation of HDPCs on both Day 7 and Day 14, while the D-gel showed the highest enhancement effects. Meanwhile, the D-gel promoted calcium accumulation and mineralized matrix deposition on Day 21. The D-gel activated MAPK-ERK1/2 pathways in HDPCs and induced the odontogenic differentiation via ERK1/2 and transforming growth factor/smad pathways. Overall, our study demonstrated that the amelogenin peptide hydrogel stimulated the odontogenic differentiation and enhanced mineralization, which held big potential in the dentine-pulp complex regeneration.

A Hydrogel as a Bespoke Delivery Platform for Stromal Cell-Derived Factor-1.

The defined self-assembly of peptides (SAPs) into nanostructured bioactive hydrogels has great potential for repairing traumatic brain injuries, as they maintain a stable, homeostatic environment at an injury site, preventing further degeneration. They also present a bespoke platform to restore function via the naturalistic presentation of therapeutic proteins, such as stromal-cell-derived factor 1 (SDF-1), expressed by meningeal cells. A key challenge to the use of the SDF protein, however, is its rapid diffusion and degradation. Here, we engineered a homeostatic hydrogel produced by incorporating recombinant SDF-1 protein within a self-assembled peptide hydrogel to create a supportive milieu for transplanted cells. Our hydrogel can concomitantly deliver viable primary neural progenitor cells and sustained active SDF-1 to support the nascent graft, resulting in increased neuronal differentiation. Moreover, this homeostatic hydrogel can ensure a healthy and larger graft core without impeding neuronal fiber growth and innervation. These findings demonstrate the regenerative potential of these hydrogels to improve the integration of grafted cells to treat neural injuries and diseases.