Natural deep eutectic systems (NADES), which have applications as solvents for both engineering and life sciences, are mainly composed of sugars, aminoacids or organic acids. In this work NADES composed by glucose, urea and proline (G:U:P in a molar ratio of 1:1:1) and proline and glucose (P:G 5:3) were prepared and added in different mass fractions to water. By differential scanning calorimetry it was verified as the crystallization tendency of water is modified even for low fraction of NADES added. This is also observed by polarized optical microscopy which allowed following the formation of crystals with different crystalline morphologies as bulk water. Calorimetric data also shown as the crystallization temperature decreases for all P:G mixtures and this shift is more accentuated for weight fraction of NADES higher than 0.5. Crystallization is totally suppressed for NADES fraction higher than 0.7. NADES/water mixtures cytotoxicity was evaluated in vitro, revealing that they are less toxic as compared with the commonly used cryoprotective additives as dimethyl sulfoxide (DMSO). Additionally, cell viability tests with cell lines cryopreserved using DMSO and both the prepared NADES showed comparable viability. This work combines thermophysical data on NADES and evaluates it's in vitro performance, providing cues for their use in cryopreservation applications.

Scaffolds mimicking structural and chemical characteristics of the native bone tissues are critical for bone tissue engineering. Herein, we have developed and characterized epigallocatechin gallate/duck's feet collagen/hydroxyapatite (EGCG/DC/HAp) composite sponges that enhanced the bone tissue regeneration. The three-dimensional composite sponges were synthesized by loading various amounts (i.e. 1, 5 and 10 μM) of EGCG to duck feet derived collagen followed by freeze-drying and then coating with hydroxyapatite. Several measuremental techniques were employed to examine the properties of the as-fabricated composite sponges including morphology and structure, porosity, compressive strength, etc. and as well compared with pristine duck feet derived collagen. SEM observations of EGCG/DC/HAp sponges showed the formation of a highly porous collagen matrix with EGCG embodiment. The porosity and pore size of sponges were found to increase by high EGCG content. The compressive strength was calculated as 3.54 ± 0.04, 3.63 ± 0.03, 3.89 ± 0.05, 4.047 ± 0.05 MPa for 1, 5 and 10 μM EGCG/DC/HAp sponges, respectively. Osteoblast-like cell (BMSCs isolated from rabbit) culture and in vivo experiments with EGCG/DC/HAp sponges implanted in nude mouse followed by histological staining showed enhanced cell internalization and attachment, cell proliferation, alkaline phosphatase expressions, indicating that EGCG/DC/HAp sponges have ahigh biocompatibility. Moreover, highEGCG content in the EGCG/DC/HAp sponges have led to increased cellular behavior. Collectively, the 5 μM of EGCG/DC/HAp sponges were suggested as the potential candidates for bone tissue regeneration.

The design and processing of appropriate porous 3-D scaffolds is one of the most important steps towards the regeneration of damaged tissues/organs using a tissue engineering approach; since most of the cell types require an adequate support in order to form the intended new tissue. TIlls work reports the development of several processing techniques that have been specifically designed for producing biodegradable scaffolds from a range of starch based polymers. The developed methods include melt based processing technologies (based on injection molding and extrusion using blowing agents), combined techniques based on solvent casting and on compression molding associated to particle leaching, It .has been possible to produce scaffolds that combine an appropriate degradation rate, with controlled porosity and adequate pore sizes, as well as tissue matching mechanical properties. Furthermore, the developed methods have no negative effect on the biocompatible behavior of the starch based polymers.

Limitations of current treatments for intervertebral disc (IVD) degeneration encourage the development of tissue engineering approaches. Injectable hydrogels loaded with cells can be used as substitute material for the inner part of the IVD, the nucleus pulposus (NP), and provide an opportunity for minimally invasive treatment of IVD degeneration. The NP is populated by chondrocyte-like cells, therefore, chondrocytes and mesenchymal stem cells (MSC), stimulated to differentiate along the chondrogenic lineage could be used to promote NP regeneration. Herein, it is investigated the in vitro and in vivo response of bone marrow-derived MSC and nasal chondrocytes (NC) to modified gellan gum-based hydrogels. Both ionic- (iGG-MA) and photo-crosslinked (phGG-MA) methacrylated gellan gum showed no cytotoxicity in extraction assays with MSC and NC. Furthermore, the materials did not induce pro-inflammatory responses in endothelial cells. MSC and NC attached and formed a monolayer on the hydrogels surface. Moreover, both cell types could be encapsulated into the hydrogels and remained viable for at least 2 weeks, as observed by live cell staining and histochemistry. Importantly, encapsulated MSC and NC showed signs of in vivo chondrogenesis, in an subcutaneous implantation model. Altogether, the data confirm the potential of modified gellan gum-based materials in NP tissue engineering.

Tissue engineering and regenerative medicine (TERM) has caused a revolution in present and future trends of medicine and surgery. In different tissues, advanced TERM approaches bring new therapeutic possibilities in either general population as in young patients and high-level athletes, improving restoration of biological functions and rehabilitation. The mainstream components required to obtain a functional regeneration of tissues may include biodegradable scaffolds, drugs or growth factors and different cell types (either autologous or heterologous) that can be cultured in bioreactor systems (in vitro) prior implantation into the patient. Particularly in the ankle, that is subject of many different injuries (e.g. acute, chronic, traumatic, degenerative), there is still no definitive and feasible answer to “conventional” methods. This review aims to provide current concepts of TERM applications to ankle injuries under pre-clinical and/or clinical research applied to skin, tendon, bone and cartilage problems. A particular attention has been given to biomaterials design and scaffolds processing with potential use in osteochondral ankle lesions.

In the field of tissue engineering and regenerative medicine (TERM), the use of traditional biomaterials capable of integrating the host tissue to promote the healing and regenerative process while it degrades has become less and less a focus of inspiration. The current trend is to increase the complexity of the host materials in order to better emulate the extracellular microenvironment of heathy and disease tissues. Thus, the combination of materials engineering with other emerging fields, such as nanotechnology, cell and molecular therapy, and precision medicine, can allow for the development of innovative biopolymer-based scaffolds for specific biomedical approaches.

Gelatin capsules (GCs) with mean size between 200 and 400 nm are prepared via sonochemical method. Their size is low that the usual size for the sonochemically obtained protein capsules and depends on the preparation conditions. The nanometer size of GCs is explained by the low-gelatin concentration and by the denaturated state of gelatin. The influence of pH, sonication time, and temperature on GCs size is investigated. An increase in temperature and sonication time results into GCs size increase. The pH dependence of GCs size passes through a minimum at the isoelectric point of gelatin. The broad size distribution detected by dynamic light scattering and scanning electron microscopy is explained by the broad molecular weight distribution of gelatin. GCs are successfully applied for encapsulation of two hydrophobic drugs, α-tocopherol and acetylsalicylic acid, in order to demonstrate the versatility of the sonochemical method for drug encapsulation. In the case of α-tocopherol drug entrapment efficiency as high as 95% is obtained.

Naturally derived polymers have been extensively used in scaffold production for cartilage tissue engineering. The present work aims to evaluate and characterize extracellular matrix (ECM) formation in two types of chitosan-based scaffolds, using bovine articular chondrocytes (BACs). The influence of these scaffolds’ porosity, as well as pore size and geometry, on the formation of cartilagineous tissue was studied. The effect of stirred conditions on ECM formation was also assessed. Chitosan-poly(butylene succinate) (CPBS) scaffolds were produced by compression moulding and salt leaching, using a blend of 50% of each material. Different porosities and pore size structures were obtained. BACs were seeded onto CPBS scaffolds using spinner flasks. Constructs were then transferred to the incubator, where half were cultured under stirred conditions, and the other half under static conditions for 4 weeks. Constructs were characterized by scanning electron microscopy, histology procedures, immunolocalization of collagen type I and collagen type II, and dimethylmethylene blue assay for glycosaminoglycan (GAG) quantification. Both materials showed good affinity for cell attachment. Cells colonized the entire scaffolds and were able to produce ECM. Large pores with random geometry improved proteoglycans and collagen type II production. However, that structure has the opposite effect on GAG production. Stirred culture conditions indicate enhancement of GAG production in both types of scaffold.

In this study, we manufactured various ratios of polycaprolactone (PCL)/gelatin (GE) highly aligned electrospun nanofibrous scaffolds (ENs) to investigate the effects of polymer ratio on tenogenic differentiation activity. For biological assessments, the cell proliferation rate was optimal in the PCL/GE (9:1) group. Interestingly, however, the tenogenic differentiation rate was best for the PCL/GE (7:3) group. From our outcomes, we established that a poly-blending mix of PCL/GE (7:3) is a promising ratio for tenogenic differentiation. Thus, our findings may provide for an effective mesh to promote tenogenic differentiation of ENs in future tendon tissue engineering applications.

Evaluating the biomedical potential of marine biopolymers is a promising strategy for their high-value application. This study investigated the ability of collagen derived from Chondrosia reniformis to support cell proliferation and chondrogenic differentiation, assessing its suitability for tissue regeneration. Collagen was isolated, preserving its fibrillar structure and glycosylation features, then cross-linked with EDC, genipin, or glutaraldehyde to produce freeze-dried scaffolds. The resulting structures were characterized in terms of physicochemical properties, morphology, degradation, rheology, and cytocompatibility. While all scaffolds showed comparable degradation and rheological behavior, genipin-cross-linked scaffolds exhibited larger pore sizes, whereas glutaraldehyde-cross-linked scaffolds showed higher water uptake. In vitro assays using ATDC5, BJ, and EA.hy926 cell lines demonstrated superior metabolic activity and proliferation on genipin-cross-linked scaffolds. Additionally, human adipose stem cells displayed early chondrogenic differentiation, evidenced by SOX9, ACAN, and COMP expression under basal conditions. These findings highlight the versatility of C. reniformis collagen for biomedical applications, particularly cartilage regeneration.