Oxidized carboxymethyl cellulose/gelatin in situ gelling hydrogel for accelerated diabetic wound healing: Synthesis, characterization, and in vivo investigations

Diabetic wounds are chronic wounds that are currently affecting many patient's quality of life. These wounds are challenging because of the impaired healing cycle and harsh environment. In this study in situ gelling hydrogels based on oxidized carboxymethyl cellulose (OCMC) and gelatin (Gel) were used to hasten the healing rate due to their ease of application. The suggested system in this work is synthesized from entirely natural renewable biomaterials to not only achieve the best biocompatibility and biodegradability but also to develop a sustainable product. The rheological studies showed that the hydrogel is turned into a gel after about 30 s of the mixing process. Moreover, the hydrogel can absorb about ten times its weight, keeping the wound hydrated. In vitro biological investigations indicated optimal biocompatibility, antibacterial, and antioxidant activity for faster tissue regeneration. This product was tested in vivo on normal rats and diabetic mice models to treat full-thickness incisional wounds. Results showed that the OCMC-Gel hydrogel is able to hasten the healing rate in both non-diabetic and diabetic wounds. Pathological examinations of the regenerated skin tissue revealed that the OCMC-Gel treated groups developed much more than the control group.

Accelerating the development of implantable neurochemical biosensors by using existing clinically applied depth electrodes

In this study, an implantable stereo-electroencephalography (sEEG) depth electrode was functionalised with an enzyme coating for enzyme-based biosensing of glucose and L-glutamate. This was done because personalised medicine could benefit from active real-time neurochemical monitoring on small spatial and temporal scales to further understand and treat neurological disorders. To achieve this, the sEEG depth electrode was characterised using cyclic voltammetry (CV), differential pulse voltammetry (DPV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) using several electrochemical redox mediators (potassium ferri/ferrocyanide, ruthenium hexamine chloride, and dopamine). To improve performance, the Pt sensors on the sEEG depth electrode were coated with platinum black and a crosslinked gelatin-enzyme film to enable enzymatic biosensing. This characterisation work showed that producing a useable electrode with a good electrochemical response showing the expected behaviour for a platinum electrode was possible. Coating with Pt black improved the sensitivity to H₂O₂ over unmodified electrodes and approached that of well-defined Pt macro disc electrodes. Measured current showed good dependence on concentration, and the calibration curves report good sensitivity of 29.65 nA/cm²/μM for glucose and 8.05 nA/cm²/μM for L-glutamate with a stable, repeatable, and linear response. These findings demonstrate that existing clinical electrode devices can be adapted for combined electrochemical and electrophysiological measurement in patients and obviate the need to develop new electrodes when existing clinically approved devices and the associated knowledge can be reused. This accelerates the time to use and application of in vivo and wearable biosensing for diagnosis, treatment, and personalised medicine.

Corrosion behavior, in vitro and in vivo biocompatibility of a newly developed Ti-16Nb-3Mo-1Sn superelastic alloy

The biocompatibility of a recently developed Ni-free Ti-16Nb-3Mo-1Sn (at.%) superelastic alloy was investigated both in vitro and in vivo. In addition, static water contact angle (WCA) and electrochemical tests were carried out. Commercial purity Ti (cp-Ti), which is already being used as a clinical material, was used as the control material. The alloy showed a stable corrosion behavior similar to that of the cp-Ti. The WCA measurements showed that the alloy exhibited hydrophilic properties that contributed to cell attachment to implants, as evident by the cytocompatibility tests. According to the in vivo implantation tests conducted on 30 adult BALB/c rats for periods up to 12 weeks, the tissue reaction around the implants was similar for both the cp-Ti and the alloy, and no significant difference was found in almost all parameters analyzed. Due to its stable superelastic properties accompanied with excellent biocompatibility and high corrosion resistance, we believe that this alloy is considered as a promising substitute for the biomedical materials containing Ni or other toxic elements.

In Vivo Formation of Stable Hyaline Cartilage by Naïve Human Bone Marrow Stromal Cells with Modified Fibrin Microbeads

Osteoarthritic and other types of articular cartilage defects never heal on their own. Medicinal and surgical approaches are often ineffective, and the supply of autologous chondrocytes for tissue engineering is very limited. Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) have been suggested as an adequate cell source for cartilage reconstruction. However, the majority of studies employing BMSCs for cartilage tissue engineering have used BMSCs predifferentiated into cartilage prior to implantation. This strategy has failed to achieve formation of stable, hyaline-like cartilage, resistant to hypertrophy in vivo. We hypothesized that in vitro predifferentiation of BMSCs is not necessary when cells are combined with an adequate scaffold that supports the formation of stable cartilage in vivo. In this study, naïve (undifferentiated) human BMSCs were attached to dehydrothermally crosslinked stable fibrin microbeads (FMBs) without and with other scaffolds and implanted subcutaneously into immunocompromised mice. Optimal formation of abundant, hypertrophy-resistant, ectopic hyaline-like cartilage was achieved when BMSCs were attached to FMBs covalently coated with hyaluronic acid. The cartilage that was formed was of human origin and was stable for at least 28 weeks in vivo. Stem Cells Translational Medicine 2019;8:586-592.