Comprehensive Review on Hydrogels

: The conventional drug delivery systems have a long list of issues of repeated dosing and toxicity arising due to it. The hydrogels are the answer to them and offer a result that minimizes such activities and optimizes therapeutic benefits. The hydrogels proffer tunable properties that can withstand degradation, metabolism, and controlled release moieties. Some of the areas of applications of hydrogels involve wound healing, ocular systems, vaginal gels, scaffolds for tissue, bone engineering, etc. They consist of about 90% of the water that makes them suitable bio-mimic moiety. Here, we present a birds-eye view of various perspectives of hydrogels, along with their applications.

Assessment of a PCL-3D Printing-Dental Pulp Stem Cells Triplet for Bone Engineering: An In Vitro Study

The search of suitable combinations of stem cells, biomaterials and scaffolds manufacturing methods have become a major focus of research for bone engineering. The aim of this study was to test the potential of dental pulp stem cells to attach, proliferate, mineralize and differentiate on 3D printed polycaprolactone (PCL) scaffolds. A 100% pure Mw: 84,500 ± 1000 PCL was selected. 5 × 10 × 5 mm3 parallelepiped scaffolds were designed as a wood-pilled structure composed of 20 layers of 250 μm in height, in a non-alternate order ([0,0,0,90,90,90°]). 3D printing was made at 170 °C. Swine dental pulp stem cells (DPSCs) were extracted from lower lateral incisors of swine and cultivated until the cells reached 80% confluence. The third passage was used for seeding on the scaffolds. Phenotype of cells was determined by flow Cytometry. Live and dead, Alamar blue™, von Kossa and alizarin red staining assays were performed. Scaffolds with 290 + 30 μm strand diameter, 938 ± 80 μm pores in the axial direction and 689 ± 13 μm pores in the lateral direction were manufactured. Together, cell viability tests, von Kossa and Alizarin red staining indicate the ability of the printed scaffolds to support DPSCs attachment, proliferation and enable differentiation followed by mineralization. The selected material-processing technique-cell line (PCL-3D printing-DPSCs) triplet can be though to be used for further modelling and preclinical experiments in bone engineering studies.

Tuning of Titanium Microfiber Scaffold with UV-Photofunctionalization for Enhanced Osteoblast Affinity and Function

Titanium (Ti) is an osteoconductive material that is routinely used as a bulk implant to fix and restore bones and teeth. This study explored the effective use of Ti as a bone engineering scaffold. Challenges to overcome were: (1) difficult liquid/cell infiltration into Ti microfiber scaffolds due to the hydrophobic nature of Ti; and (2) difficult cell attachment on thin and curved Ti microfibers. A recent discovery of UV-photofunctionalization of Ti prompted us to examine its effect on Ti microfiber scaffolds. Scaffolds in disk form were made by weaving grade 4 pure Ti microfibers (125 µm diameter) and half of them were acid-etched to roughen the surface. Some of the scaffolds with original or acid-etched surfaces were further treated by UV light before cell culture. Ti microfiber scaffolds, regardless of the surface type, were hydrophobic and did not allow glycerol/water liquid to infiltrate, whereas, after UV treatment, the scaffolds became hydrophilic and immediately absorbed the liquid. Osteogenic cells from two different origins, derived from the femoral and mandibular bone marrow of rats, were cultured on the scaffolds. The number of cells attached to scaffolds during the early stage of culture within 24 h was 3–10 times greater when the scaffolds were treated with UV. The development of cytoplasmic projections and cytoskeletal, as well as the expression of focal adhesion protein, were exclusively observed on UV-treated scaffolds. Osteoblastic functional phenotypes, such as alkaline phosphatase activity and calcium mineralization, were 2–15 times greater on UV-treated scaffolds, with more pronounced enhancement on acid-etched scaffolds compared to that on the original scaffolds. These effects of UV treatment were associated with a significant reduction in atomic carbon on the Ti microfiber surfaces. In conclusion, UV treatment of Ti microfiber scaffolds tunes their physicochemical properties and effectively enhances the attachment and function of osteoblasts, proposing a new strategy for bone engineering.