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Rheology plays a vital role in pneumatic three-dimensional (3D) printing of hydrogels. This study investigates the rheological behavior of a novel self- healing hydrogel (O-MOG/CMCh) formed by a Schiff base crosslinking reaction between oxidized Moringa oleifera gum (O-MOG), a biodegradable antimicrobial polysaccharide, and carboxymethyl chitosan (CMCh), a water-soluble biocompatible cliitosan derivative. Three hydrogel formulations were designed using 5% w/v of CMCh with varied concentrations of O-MOG (3% w/v, 4% w/v, and 5% w/v) and evaluated through rheology analyses, including frequency sweeps, amplitude sweeps, oscillatory thixotropy, and gelation kinetics. These tests revealed that the material has shear thinning, self-healing properties, a high linear viscoelastic region (LVE), and gel formation times ([t.sub.gel]) of 3.23-4.57 min. The hydrogel synthesized with 5% w/v of O-MOG composition exhibited the best characteristics for printability based on rheological assessments, and this composition was used for further printing assessment, where bi-layered 4x4 and 2x2 grids were successfully printed using 22 G (0.41 mm) and 23 G (0.34 mm) syringes. All the constructs had a printability index value of 1 [+ or -] 0.13 and spreading ratios Highlights * Self-healing hydrogel was prepared by mixing the precursors through a cannula. * Rheology was examined using standard tests for printability assessment. * 3D printability was achieved using two different gauze syringes. * Printability parameters were recorded and analyzed for the constructs. KEYWORDS 3D printability, additive manufacturing, carboxymethyl chitosan, Moringa oleifera gum, rheology, Schiff base, 1 | INTRODUCTION 3D printing forms three-dimensional objects by successive adding layers of material as per the programmed model. (1) Polymeric hydrogels are generally printed using the extrusion 3D printing [...]

The limited replicative potential of primary hepatocytes (Hep) is a major hurdle for obtaining sufficient quantity and quality hepatocytes during cell therapy in patients with liver failure. Intrahepatic cholangiocyte organoids (ICOs) derived from intrahepatic bile ducts differentiate into both hepatocytes and cholangiocytes in vitro. Here, we studied in vivo effects of transplanting ICOs and Hep in chronic liver injury mice models. Well characterized primary mouse ICOs and Hep were mixed in decellularized liver (DCL) matrix hydrogels and injected into the subcapsular left lateral liver lobe of CCl4-induced liver injury models whereas mice given DCL alone were in the sham group. Two weeks post-transplantation, transplanted liver lobes were collected and studied by histology and RNA sequencing. Transplanted animals did not exhibit any tumors, mortality or morbidity. Mice livers transplanted with ICOs had increased cellular proliferation and vascularization as compared to Hep transplanted mice or sham. Collagen deposition in the liver was significantly reduced and serum albumin levels were significantly increased in transplanted groups compared to the sham group. Expression of genes associated with hepatocyte differentiation was highest in Hep transplanted livers among the three groups, but they were also upregulated in ICO transplanted livers compared to sham. Our study demonstrates that ICOs encapsulated in DCL hydrogels when transplanted in chronically injured mice livers engraft well and show hepatocyte differentiation and reduction of fibrosis, indicating that hydrogel transplanted cholangiocyte organoids may serve as an efficient cell source and therapy for renewal of hepatocytes, restoration of hepatocyte functions and resolution of liver injury. [ABSTRACT FROM AUTHOR]

Silk is a widely accepted biomaterial for tissue regeneration owing to its tunable biomechanical properties and ease of chemical modification. However, a number of aspects associated with its clinical use are still debated. Indeed, to achieve clinical success, a biomaterial must favorably interact with host tissues without evoking local or systemic immuno-inflammatory responses. The analysis of immune responses associated with silk under in vitro and in vivo conditions provides useful insights, improving the understanding of the functional characteristics of silk biomaterials and further promoting their clinical application. Silk evokes moderate immune responses upon implantation in vivo, depending on the material structure, fabrication method, degradation time, and implantation in soft or hard tissue sites, which rapidly subside within a few days/weeks. In vitro studies indicate that its immune-stimulatory properties are largely due to inherent protein conformation and differential processing parameters. Strategically controlled levels of immune responses in vivo with marginal immunogenicity of silk-based biomaterials may contribute to matrix remodeling and replacement by native tissue matrix around the implanted site. Therefore, immunomodulatory strategies should be developed to promote the use of silk-based biomaterials as promising candidates for numerous clinical applications. [ABSTRACT FROM AUTHOR]

RNA-based therapeutics have exhibited remarkable potential in targeting genetic factors for disease intervention, exemplified by recent mRNA vaccines for COVID-19. Nevertheless, the intrinsic instability of RNA and challenges related to its translational efficiency remain significant obstacles to the development of RNA as therapeutics. This study introduces an innovative RNA delivery approach using a silk fibroin (SF) and positively charged gelatin (Gel) hydrogel matrix to enhance RNA stability for controlled release. As a proof of concept, whole-cell RNA was incorporated into the hydrogel to enhance interactions with RNA molecules. Additionally, molecular modeling studies were conducted to explore the interactions between SF, collagen, chitosan (Chi), and the various RNA species including ribosomal RNAs (28S, 18S, 8.5S, and 5S rRNAs), transfer RNAs (tRNA-ALA, tRNA-GLN, and tRNA-Leu), as well as messenger RNAs (mRNA-GAPDH, mRNA-β actin, and mRNA-Nanog), shedding light on the RNA–polymer interaction and RNA stability; SF exhibits a more robust interaction with RNA compared to collagen/gel and chitosan. We confirmed the molecular interactions of SF and RNA by FTIR and Raman spectroscopy, which were further supported by AFM and contact angle measurement. This research introduces a novel RNA delivery platform and insights into biopolymer–RNA interactions, paving the way for tailored RNA delivery systems in therapeutics and biomedical applications. [ABSTRACT FROM AUTHOR]