Injectable Liposome-Loaded Hydrogel Formulations with Controlled Release of Curcumin and α-Tocopherol for Dental Tissue Engineering.

An injectable hydrogel formulation is developed utilizing low- and high-molecular-weight chitosan (LCH and HCH) incorporated with curcumin and α-tocopherol-loaded liposomes (Lip/Cur+Toc). Cur and Toc releases are delayed within the hydrogels. The injectability of hydrogels is proved via rheological analyses. In vitro studies are conducted using human dental pulp stem cells (hDPSCs) and human gingival fibroblasts (hGFs) to examine the biological performance of the hydrogels toward endodontics and periodontics, respectively. The viability of hDPSCs treated with the hydrogels with Lip/Cur+Toc is the highest till day 14, compared to the neat hydrogels. During odontogenic differentiation tests, alkaline phosphatase (ALP) enzyme activity of hDPSCs is induced in the Cur-containing groups. Biomineralization is enhanced mostly with Lip/Cur+Toc incorporation. The viability of hGFs is the highest in HCH combined with Lip/Cur+Toc while wound healing occurs almost 100% in both (Lip/Cur+Toc@LCH and Lip/Cur+Toc@HCH) after 2 days. Antioxidant activity of Lip/Cur+Toc@LCH on hGFs is significantly the highest among the groups. Antimicrobial tests demonstrate that Lip/Cur+Toc@LCH is more effective against Escherichia coli whereas so is Lip/Cur+Toc@HCH against Staphylococcus aureus. The antimicrobial mechanism of the hydrogels is investigated for the first time through various computational models. LCH and HCH loaded with Lip/Cur+Toc are promising candidates with multi-functional features for endodontics and periodontics.

A comprehensive review on hydrogel materials in urology: Problems, methods, and new opportunities.

Hydrogel materials provide an extremely promising group of materials that can find an increasingly wide range of use in treating urinary system conditions due to their unique properties. The present review describes achievements to date in terms of the use and development prospects of hydrogel materials applications in the treatment and reconstruction of the urinary system organs, which among others include: hydrogel systems of intravesical drug delivery, ureteral stents design, treatment of vesicoureteral reflux, urinary bladder and urethral defects reconstruction, design of modern urinary catheters and also solutions applied in urinary incontinence therapy (Figure 4). In addition, hydrogel materials find increasingly growing applications in the construction of educational simulation models of organs and specific conditions of the urinary system, which enable the education of medical personnel. Numerous research efforts are underway to expand the existing treatment methods and reconstruction of the urinary system based on hydrogel materials. After conducting the further necessary research, many of the innovative solutions developed to date have high application potential.

Solvent types used for the preparation of hydrogels determine their mechanical properties and influence cell viability through gelatine and calcium ions release.

Alginate-gelatin hydrogels are the most commonly used materials for 3D bioprinting. Their printability depends on their properties, and these derive from the way they are prepared and their very composition. Therefore, the aim of the study was to investigate the type of solvent (deionized water, phosphate buffer, and culture medium) and contents of gelatin in the composition of hydrogel (2% wt/vol alginate, 6% and 9% wt/vol of gelatin) on their biological, physicochemical, and mechanical properties, as well as printability and the ability of cells to proliferate in the printed structures. The results obtained revealed that all the manufactured hydrogel materials are biocompatible. The use of deionized water as a solvent results in the highest degree of cross-linking of hydrogels, thus obtaining a polymer with the highest rigidity. Moreover, an increase in gelatin content leads to an increase in the Young's modulus value, irrespectively of the solvent in which the hydrogels were prepared. Based on the chemical structure, it is more reasonable to use a culture medium for bioink preparation due to free NH and NH2 groups being present, which are ligands for cell attachment and their proliferation. For the selected material (2A9GM), the printability and high viability of the cells after printing were confirmed. In this case, the concentration of the cross-linking agent influences gelatin amount release and calcium ions release, and these two processes determine the change in the viability of the cells encapsulated in the bioink.

Evaluation of Polysaccharide-Peptide Conjugates Containing the RGD Motif for Potential Use in Muscle Tissue Regeneration.

New scaffold materials composed of biodegradable components are of great interest in regenerative medicine. These materials should be: stable, nontoxic, and biodegrade slowly and steadily, allowing the stable release of biodegradable and biologically active substances. We analyzed peptide-polysaccharide conjugates derived from peptides containing RGD motif (H-RGDS-OH (1), H-GRGDS-NH2 (2), and cyclo(RGDfC) (3)) and polysaccharides as scaffolds to select the most appropriate biomaterials for application in regenerative medicine. Based on the results of MTT and Ki-67 assays, we can state that the conjugates containing calcium alginate and the ternary nonwoven material were the most supportive of muscle tissue regeneration. Scanning electron microscopy imaging and light microscopy studies with hematoxylin-eosin staining showed that C2C12 cells were able to interact with the tested peptide-polysaccharide conjugates. The release factor (Q) varied depending on both the peptide and the structure of the polysaccharide matrix. LDH, Alamarblue®, Ki-67, and cell cycle assays indicated that peptides 1 and 2 were characterized by the best biological properties. Conjugates containing chitosan and the ternary polysaccharide nonwoven with peptide 1 exhibited very high antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae. Overall, the results of the study suggested that polysaccharide conjugates with peptides 1 and 2 can be potentially used in regenerative medicine.

Influence of Different Nanometals Implemented in PMMA Bone Cement on Biological and Mechanical Properties.

Cemented arthroplasty is a common process to fix prostheses when a patient becomes older and his/her bone quality deteriorates. The applied cements are biocompatible, can transfer loads, and dampen vibrations, but do not provide antibacterial protection. The present work is aimed at the development of cement with antibacterial effectivity achieved with the implementation of nanoparticles of different metals. The powders of Ag, Cu with particles size in a range of 10-30 nm (Cu10) and 70-100 nm (Cu70), AgCu, and Ni were added to PMMA cement. Their influence on compression strength, wettability, and antibacterial properties of cement was assessed. The surface topography of samples was examined with biological and scanning electron microscopy. The mechanical properties were determined by compression tests. A contact angle was observed with a goniometer. The biological tests included an assessment of cytotoxicity (XTT test on human cells Saos-2 line) and bacteria viability exposure (6 months). The cements with Ag and Cu nanopowders were free of bacteria. For AgCu and Ni nanoparticles, the bacterial solution became denser over time and, after 6 months, the bacteria clustered into conglomerates, creating a biofilm. All metal powders in their native form in direct contact reduce the number of eukaryotic cells. Cell viability is the least limited by Ag and Cu particles of smaller size. All samples demonstrated hydrophobic nature in the wettability test. The mechanical strength was not significantly affected by the additions of metal powders. The nanometal particles incorporated in PMMA-based bone cement can introduce long-term resistance against bacteria, not resulting in any serious deterioration of compression strength.

Induced Biological Response in Contact with Ag-and Cu-Doped Carbon Coatings for Potential Orthopedic Applications.

Silver and copper as additives of various biomaterials have been reported as the potential solutions for biomedicine applications, mostly because of inducing bactericidal effects. The application of those admixtures in diamond-like carbon (DLC) coatings may be desirable for orthopedic implants. In the present manuscript, the biological effect of coatings with up to about 7 at.% and 14 at.% of, respectively, Cu and Ag is compared. The morphology, chemical structure, and composition of films deposited on AISI 316LVM and Ti6Al7Nb is characterized. The live/dead analysis conducted with Escherichia coli shows a higher bactericidal potential of silver than copper. Although the Cu-doped coatings can positively affect the proliferation of Saos-2 and EA.hy926 cell lines, the results of XTT test are on the verge of 70% of viability. Biological effect of silver on EA.hy926 cell lines is negative but that admixture ensures high proliferation of osteoblasts in contact with coatings deposited on titanium alloy (over 20% better than for substrate material). In that case, the viability is reaching about 85% for Ag-doped coatings on AISI 316LVM and 75% on Ti6Al7Nb. The results indicate that for the sake of bactericidal coatings that may promote osteointegration, the candidates are DLC with silver content no higher than 10 at.%.

An Integration of a Peristaltic Pump-Based Extruder into a 3D Bioprinter Dedicated to Hydrogels.

The 3D printing technologies used for medical applications are mostly based on paste extruders. These are designed for high capacity, and thus often feature large material reservoirs and large diameter nozzles. A major challenge for most 3D printing platforms is a compromise between speed, accuracy, and/or volume/mass of moving elements. To address these issues, we integrated a peristaltic pump into a bioprinter. That allowed for combining the most important requirements: high precision, a large material reservoir, and safety of biological material. The system of a fully heated nozzle and a cooled print bed were developed to maintain the optimal hydrogel temperature and crosslinking speed. Our modifications of the bioprinter design improved the mechanical properties of the printouts and their accuracy while maintaining the maximal survival rate of cells and increasing the capacity of the bioink reservoir.

Sodium Alginate/Gelatine Hydrogels for Direct Bioprinting-The Effect of Composition Selection and Applied Solvents on the Bioink Properties.

Hydrogels tested and evaluated in this study were developed for the possibility of their use as the bioinks for 3D direct bioprinting. Procedures for preparation and sterilization of hydrogels and the speed of the bioprinting were developed. Sodium alginate gelatine hydrogels were characterized in terms of printability, mechanical, and biological properties (viability, proliferation ability, biocompatibility). A hydrogel with the best properties was selected to carry out direct bioprinting tests in order to determine the parameters of the bioink, adapted to print with use of the designed and constructed bioprinter and provide the best conditions for cell growth. The obtained results showed the ability to control mechanical properties, biological response, and degradation rate of hydrogels through the use of various solvents. The use of a dedicated culture medium as a solvent for the preparation of a bioink, containing the predicted cell line, increases the proliferation of these cells. Modification of the percentage of individual components of the hydrogel gives the possibility of a controlled degradation process, which, in the case of printing of temporary medical devices, is a very important parameter for the hydrogels' usage possibility-both in terms of tissue engineering and printing of tissue elements replacement, implants, and organs.

Surface Characteristics and Biological Evaluation of Si-DLC Coatings Fabricated Using Magnetron Sputtering Method on Ti6Al7Nb Substrate.

Diamond-like carbon (DLC) coatings are well known as protective coatings for biomedical applications. Furthermore, the incorporation of different elements, such as silicon (Si), in the carbon matrix changes the bio-functionality of the DLC coatings. This has also been proven by the results obtained in this work. The Si-DLC coatings were deposited on the Ti6Al7Nb alloy, which is commonly used in clinical practice, using the magnetron sputtering method. According to the X-ray photoelectron spectroscopy (XPS) analysis, the content of silicon in the examined coatings varied from ~2 at.% up to ~22 at.%. Since the surface characteristics are key factors influencing the cell response, the results of the cells' proliferation and viability assays (live/dead and XTT (colorimetric assays using tetrazolium salt)) were correlated with the surface properties. The surface free energy (SFE) measurements, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the polarity and wettability of the surfaces examined increase with increasing Si concentration, and therefore the adhesion and proliferation of cells was enhanced. The results obtained revealed that the biocompatibility of Si-doped DLC coatings, regardless of the Si content, remains at a very high level (the observed viability of endothelial cells is above 70%).

Fabrication of antimicrobial silver-doped carbon structures by combinatorial pulsed laser deposition.

We report on the selection by combinatorial pulsed laser deposition of Silver-doped Carbon structures with reliable physical-chemical characteristics and high efficiency against microbial biofilms. The investigation of the films was performed by scanning electron microscopy, high resolution atomic force microscopy, energy dispersive X-Ray Spectroscopy, X-ray diffraction, Raman spectroscopy, bonding strength "pull-out" tests, and surface energy measurements. In vitro biological assays were carried out using a large spectrum of bacterial and fungal strains, i.e., Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Enterococcus faecalis and Candida albicans. The biocompatibility of the films obtained was evaluated on MG63 mammalian cell cultures. The optimal combination with reasonable physical-chemical properties, efficient protection against microbial colonization and beneficial effects on human cells was found for Silver-doped Carbon films containing 2 to 7 at.% silver. These mixtures can be used to fabricate safe and efficient coatings of metallic implants, with the goal to decrease the risk of implant associated biofilm infections which are difficult to treat and often responsible for implant failure.

Surface characterization and biological evaluation of silver-incorporated DLC coatings fabricated by hybrid RF PACVD/MS method.

Since the biological response of the body towards an implanted material is mainly governed by its surface properties, biomaterials are improved by various kinds of coatings. Their role is to provide good mechanical and biological characteristics, and exclude some disadvantages like post-implantation infections. This phenomenon may be reduced by introduction of silver as an antibacterial agent. This study evaluates the Ag-DLC films synthesized by the hybrid RF PACVD/MS method according to the patent number PL401955-A1 worked out inter alia by the authors. Such tests as XPS, SEM, EDS, AFM, FTIR, Raman and ICP-TOF-MS were used to determine surface properties of the coatings. The obtained results were correlated with the biological response estimated on the basis of cells viability assay (osteoblast cells line Saos-2) and bacterial colonization test (Escherichia coli strain DH5α). Results showed that the hybrid RF PACVD/MS method allows one to get tight coating preventing the diffusion of harmful elements from the metallic substrate. Ag concentration increases with the growing power density, it occurs in metallic state, does not create chemical bonds and is evenly dispersed within the DLC matrix in the form of nanoscale silver clusters. Increasing silver content above 2at.% improves bactericidal properties, but decreases cell viability.

Nanostructured protective carbon layer on the jeweller's metallic material--in vitro verification.

In this paper the surface condition of jeweller's metallic material covered by nanostructured carbon layer after the in vitro model test was investigated. The phenomenon of body modification has made that the most popular and the most often applied is jewellery made of metals like stainless steel, titanium and its alloys. However these kinds of metals are not safe and can cause health complications. Biocompatible carbon coatings were used in order to exclude the side effects of metallic jewellery use. Body modification trend is popular among youth to a large degree--they who are always looking for the cheap decorations. Taking this fact into consideration the jewellery made of stainless steel, which is used the most often was exposed to modification by carbon coating. Two methods of plasma activated chemical vapour deposition (PA CVD) were used for the carbon coatings production purpose: radio frequency (RF) and microwave/radio frequency (MW/RF). In order to point the best parameters of these coatings manufacture processes, examinations of physiochemical properties and analysis of surface topography (optical microscopy, scanning electron microscopy with X-ray microanalysis) were made. So modified jewellery was investigated in in vitro model as regards resistance to the biological environment and coatings stability as well. The conducted examinations showed that modifications of decorations made of 316L stainless steel by carbon coatings allow for the creation of biocompatible, non-toxic jewellery. Tests showed that human fibroblasts grow and keep vitality in a presence of jewellery covered by carbon coating, whereas die very fast sticking the non-modified surfaces of decorations. The carbon coating constitutes a barrier which isolates jewellery from the surrounding environment and simultaneously contacts with it in a safe way.