Cell Adhesion and Proliferation on Sulfonated and Non-Modified Chitosan Films

Matricaria chamomilla essential oil-loaded hybrid electrospun nanofibers based on polycaprolactone/sulfonated chitosan/ZIF-8 nanoparticles for wound healing acceleration

Recently, developing antibacterial wound dressings based on biomaterials display good biocompatibility and the potential to accelerate wound healing. For this aim, we prepared eco-friendly and biodegradable nanofibers (NFs) based on N-(3-sulfopropyl)chitosan/ poly (ε-caprolactone) incorporated by zeolite imidazolate framework-8 nanoparticles (ZIF-8 NPs) and chamomile essential oil (MCEO) via the electrospinning technique for their efficacy as wound dressing scaffolds. Fabricated NFs were characterized and studied for their structural, morphological, mechanical, hydrophilic, and thermal stability properties. The results of scanning electron microscopy (SEM) revealed that adding the ZIF-8 NPs/ MCEO, very slightly influenced the average diameter of NFs (PCL/SPCS (90:10) with 90 ± 32 nm). The developed uniform MCEO-loaded ZIF-8/PCL/SPCS NFs displayed better cytocompatibility, proliferation, and physicochemical properties (e.g. thermal stability and mechanical properties) than neat NFs. The results of cytocompatibility, DAPI (4',6-diamidino-2-phenylindole) staining study, and SEM micrographs demonstrated that formulated NFs had promising adhesion and proliferation against normal human foreskin fibroblasts-2 (HFF-2 cell line). The prepared NFs revealed excellent antibacterial activity against both Staphylococcus aureus and Escherichia coli with inhibition of 32.3 mm and 31.2 mm, respectively. Accordingly, the newly developed antibacterial NFs hold great potential as effective biomaterials for use as an active platform in wound healing applications.

Efficient N-sulfopropylation of chitosan with 1,3-propane sultone in aqueous solutions: neutral pH as the key condition

Conjugation of strong anionic sulfonate groups to chitosan (CS) is typically used for converting the weak cationic CS to its polyampholyte derivatives, which are of interest to different areas benefiting from both cationic and anionic groups.

Transplantation of olfactory ensheathing cells combined with chitosan down-regulates the expression of P2X7 receptor in the spinal cord and inhibits neuropathic pain

BACKGROUND

Neuropathic pain (NPP) is the common symptom of most clinical diseases, and its treatment has always been a difficult problem at present. Therefore, the purpose of this study is to explore a new method for the treatment of NPP by transplanting olfactory ensheathing cells combined with chitosan (OECs-CS).

METHODS

Animal model of chronic compression sciatic nerve injury (CCI) was made, olfactory ensheathing cells (OECs) were cultured, chitosan (CS) biomaterials were prepared, and biocompatibility of OECs and CS were detected by MTT method, OECs and OECs-CS were transplanted into the site of the injured sciatic nerve respectively, behavioral method was used to measured the mechanical withdrawal thresholds (MWT) and thermal withdrawal latency (TWL) of rats. On days 7 and 14 after surgery, the expression level of P2X7 receptor (P2X7R) in the L4-5 spinal cord was measured by using in situ hybridization, western-blotting and qRT-PCR. To explore the therapeutic effect of OECs-CS transplantation on pain suppression.

RESULTS

After chronic compression sciatic nerve injury, the MWT and TWL of rats were significantly reduced, and the expression levels of P2X7R protein and mRNA in the L4-5 spinal cord was significantly increased. After the transplantation of OECs and OECs-CS, the expression levels of P2X7R was significantly reduced, and the MWT and TWL of rats were significantly increased. Importantly, compared with the transplantation of OECs, OECs-CS transplantation could better reduce the expression levels of P2X7R, and relieve hyperalgesia in rats. Moreover, compared with the CCI + OECs-CS group on days 7 after surgery, the expression levels of P2X7R in the CCI + OECs-CS group was reduced on days 14 after surgery, and the pain in rats was relieved.

CONCLUSION

OECs and OECs-CS transplantation can inhibit P2X7R overexpression mediated NPP, while OECs-CS transplantation has better therapeutic effect than OECs transplantation alone. Our results provide a novel method and theoretical basis for the treatment of NPP.

Fabrication of chitosan/agarose scaffolds containing extracellular matrix for tissue engineering applications

One of the most effective approaches for treatment of cartilage involves the use of porous three-dimensional scaffolds, which are useful for improving not only cellular adhesion but also mechanical properties of the treated tissues. In this study, we manufactured a composite scaffold with optimum properties to imitate nasal cartilage attributes. Cartilage extracellular matrix (ECM) was used in order to improve the cellular properties of the scaffolds; while, chitosan and agarose were main materials that are used to boost the mechanical and rheological properties of the scaffolds. Furthermore, we explored the effect of the various weight ratios of chitosan, agarose, and ECM on the mechanical and biomedical properties of the composite scaffolds using the Taguchi method. The resulting composites display a range of advantages, including good mechanical strength, porous morphology, partial crystallinity, high swelling ratio, controlled biodegradability rate, and rheological characteristics. Additionally, we performed the cytotoxicity tests to confirm the improvement of the structure and better cell attachments on the scaffolds. Our findings illustrate that the presence of the ECM in chitosan/agarose structure improves the biomedical characteristics of the final scaffold. In addition, we were able to control the mechanical properties and microstructure of the scaffolds by optimizing the polymers' concentration and their resulting interactions. These results present a novel scaffold with simultaneously enhanced mechanical and cellular attributes comparing to the scaffolds without ECM for nasal cartilage tissue engineering applications.

Polymeric ionically conductive composite matrices and electrical stimulation strategies for nerve regeneration: In vitro characterization

Stem cell strategies and the use of electrical stimulation (ES) represent promising new frontiers for peripheral nerve regeneration. Composite matrices were fabricated by coating electrospun polycaprolactone/cellulose acetate micro-nanofibers with chitosan and ionically conductive (IC) polymers including, sulfonated polyaniline, and lignin sulfonate. These composite matrices were characterized for surface morphology, coating uniformity, ionic conductivity, and mechanical strength to explore as scaffold materials for nerve regeneration in conjunction with ES. Composite matrices measured conductivity in the range of 0.0049-0.0068 mS/m due to the uniform coating of sulfonated polymers on the micro-nanofibers. Thin films (2D) and composite fiber matrices (3D) of IC polymers seeded with human mesenchymal stem cells (hMSCs) were electrically stimulated at 0.5 V, 20 Hz for 1 h daily for 14 days to study the changes in cell viability, morphology, and expression of the neuronal-like phenotype. In vitro ES lead to changes in hMSCs' fibroblast morphology into elongated neurite-like structures with cell bodies for ES-treated and positive control growth factor-treated groups. Immunofluorescent staining revealed the presence of neuronal markers including β3-tubulin, microtubule-associated protein 2, and nestin in response to ES. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1792-1805, 2019.

Disaccharides obtained from carrageenans as potential antitumor agents

Carrageenans are sulfated galactans found in certain red seaweeds with proven biological activities. In this work, we have prepared purified native and degraded κ-, ι-; and λ-carrageenans, including the disaccharides (carrabioses) and disaccharide-alditols (carrabiitols) from seaweed extracts as potential antitumor compounds and identified the active principle of the cytotoxic and potential antitumor properties of these compounds. Both κ and ι-carrageenan, as well as carrageenan oligosaccharides showed cytotoxic effect over LM2 tumor cells. Characterized disaccharides (carrabioses) and the reduced product carrabiitols, were also tested. Only carrabioses were cytotoxic, and among them, κ-carrabiose was the most effective, showing high cytotoxic properties, killing the cells through an apoptotic pathway. In addition, the cells surviving treatment with κ-carrabiose, showed a decreased metastatic ability in vitro, together with a decreased cell-cell and cell-matrix interactions, thus suggesting possible antitumor potential. Overall, our results indicate that most cytotoxic compounds derived from carrageenans have lower molecular weights and sulfate content. Potential applications of the results emerging from the present work include the use of disaccharide units such as carrabioses coupled to antineoplasics in order to improve its cytotoxicity and antimetastatic properties, and the use of ι-carrageenan as adjuvant or carrier in anticancer treatments.