Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: The IBU-CS-GP hydrogel was synthesized by chemically modifying chitosan with ibuprofen and subsequently using genipin as a natural crosslinker to obtain a neutral, chitosan-based injectable hydrogel. Upon minimally invasive local injection, the precursor solution undergoes in situ gelation at the injury site, modulates the local post-injury inflammatory microenvironment, and thereby promotes peripheral nerve repair. Created in https://BioRender.com . IBU, ibuprofen; CS; chitosan; GP, genipin; EDC, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; NHS, N-hydroxysuccinimide.

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Synthesized, Injection, In Situ

Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: Physicochemical properties of hydrogels. Macroscopic photos of CS–MA, CS-GP and IBU-CS-GP injectable hydrogel (A). SEM images of the cross sections of injectable hydrogels (B). Pore size (C), and porosity (D), typical compressive stress–strain curves (E) with peak compression strength (F), compressive modulus (G), and breaking strains (H), water absorption (I), in vitro degradation (J), and drug release profile (K). Unpaired two-tailed student's t -test n = 27 for C, n = 3 for D and F-K; ∗p < 0.05, n.s. CS, chitosan; IBU, ibuprofen; GP, genipin; MA, methacrylic anhydride; n.s., not significant; SEM, scanning electron microscopy.

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Pore Size, In Vitro, Two Tailed Test, Electron Microscopy

Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: Anti-inflammatory and antioxidative capacity of hydrogels. Flow cytometry (A) reveals that IBU-CS-GP hydrogel significantly promote M2 polarization of LPS-stimulated RAW264.7 macrophages (B) RT-PCR analysis suggests that IBU-CS-GP downregulates pro-inflammatory gene TNF-α (C) and upregulates anti-inflammatory genes of IL-4 (D) in comparison to CS-MA and CS-GP. IBU-CS-GP markedly attenuates ROS and NO production in LPS-stimulated macrophages, as indicated by DCFH staining (H), flow cytometry analysis (G), and ROS & NO quantification (E–F). One-way ANOVA with Tukey's post hoc test and n = 3 for B-F; ∗∗p < 0.01, ∗∗∗p < 0.001, n.s. ANOVA, analysis of variance; CS, chitosan; IBU, ibuprofen; GP, genipin; MA, methacrylic anhydride; LPS, lipopolysaccharides; n.s., not significant; NO, nitric oxide; PCR, polymerase chain reaction; ROS, reactive oxygen species; DCFH, 2′,7′-Dichlorodihydrofluorescein; DAPI, 4′,6-diamidino-2-phenylindole.

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Flow Cytometry, Reverse Transcription Polymerase Chain Reaction, Comparison, Staining, Polymerase Chain Reaction

Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: Pro-angiogenic and pro-migratory effects of hydrogels. Immunofluorescence staining shows blood vessel formation of HUVECs in LPS-macrophage condition medium (A). Scratch assays and Transwell migration assays of HUVECs (B) and L929 cells (C). Quantification of junctions (D), branches (E), wound closure percentage (F–G) and migrated cells (H–I). One-way ANOVA with Tukey's post hoc test and n = 3 for D-I; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, n.s. ANOVA, analysis of variance; CS, chitosan; IBU, ibuprofen; GP, genipin; MA, methacrylic anhydride; LPS, lipopolysaccharides; HUVEC, human umbilical vein endothelial cell; n.s., not significant.

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Immunofluorescence, Staining, Migration

Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: Functional assessment in rats after sciatic nerve crush injury. Representative hind paw footprints at different postoperative time points (A), with SFI calculated from footprint parameters (B). Electrophysiological evaluation of the sciatic nerve was performed at post-operation day 28 (C), NCV and recovery indices of CMAP were quantified (D–E). Bilateral gastrocnemius muscles were harvested and weighed at three postoperative time points (F), and the gastrocnemius wet weight ratio was calculated (G). One-way ANOVA with Tukey's post hoc test and n = 3 for B, D, E and G; ∗p < 0.05, ∗∗p < 0.01. ANOVA, analysis of variance; CS, chitosan; IBU, ibuprofen; GP, genipin; MA, methacrylic anhydride; SFI, sciatic functional index; PL, print length; TS, toe spread; IT, intermediary toe spread; NCV, nerve conduction velocity; CMAP, compound muscle action potential.

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Functional Assay, Muscles

Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: Histological evaluation of sciatic nerve and gastrocnemius muscle sections at post-operation day 28. Double immunofluorescence staining for S100β and NF200 in sciatic nerve sections (A). Double immunofluorescence staining for MBP and TUBB3 in sciatic nerve sections (B). H&E staining and TB staining of the sciatic nerve (C). Immunohistochemical staining for NF200 in the injured sciatic nerve (D). Masson's trichrome staining of gastrocnemius muscle sections(E). Quantitative analysis of the collagen fiber area fraction in the gastrocnemius muscle (F). One-way ANOVA with Tukey's post hoc test and n = 3 for F; ∗p < 0.05, ∗∗p < 0.01. ANOVA, analysis of variance; CS, chitosan; IBU, ibuprofen; GP, genipin; MA, methacrylic anhydride; S100β, a Schwann cell marker; NF200, neurofilament protein NF200; MBP, myelin basic protein; TUBB3, β3-Tubulin; H&E, hematoxylin and eosin; TB, toluidine blue. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Double Immunofluorescence Staining, Staining, Immunohistochemical staining, Marker

Journal: Materials Today Bio

Article Title: Injectable chitosan-based hydrogel via in situ gelation modulates the inflammatory microenvironment and facilitates minimally invasive repair of peripheral nerve injury

doi: 10.1016/j.mtbio.2026.102814

Figure Lengend Snippet: Transmission electron micrographs of regenerated sciatic nerves at post-operation day 28 (A). Quantitative analysis of myelin sheath thickness of regenerated myelinated fibers in each group (B). Calculated g-ratio of regenerated myelinated fibers based on morphometric measurements (C). Linear regression between g-ratio and axon diameter in each group (D). One-way ANOVA with Tukey's post hoc test and n = 9 for B-D; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001. ANOVA, analysis of variance; CS, chitosan; IBU, ibuprofen; GP, genipin; MA, methacrylic anhydride.

Article Snippet: Chitosan (degree of deacetylation 90 %, 200 kDa), ibuprofen (IBU), and genipin (GP) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China).

Techniques: Transmission Assay