2^nd Annual Conference and Expo on Biomaterials March 27-28, 2017 Madrid, Spain

T Eliades is a Professor and Director of the Clinic of Orthodontic and Paediatric Dentistry, University of Zurich, Switzerland.

Aim: To evaluate the viscoelastic properties of two experimental BPA-free and one BisGMA-based orthodontic resin composite adhesives for bonding fixed retainers.\r\n\r\nMaterials & Methods: A commercially available BisGMA-based (TXA: Transbond LR) and two Bisphenol A-free experimental adhesives (EXA and EXB) were included in the study. The viscoelastic behaviour of the\r\nadhesives were evaluated under static and dynamic conditions at dry and wet states and at various temperatures (21, 37, 50oC). The parameters determined were shear modulus (G), Young\'s modulus (E) under static testing and storage modulus (G1), loss tangent (tan δ) and dynamic viscosity (n*) under dynamic testing. Statistical analysis was performed by 2-way ANOVA and Bonferroni post-hoc tests (α=0.05).\r\n\r\nResults: For static testing, a significant difference was found within material and storage condition variables and a significant interaction between the two independent variables (p<0.001 for G and E). EXA demonstrated the highest G and E values at 21oC/dry group. Dry specimens showed the highest G and E values, but with no significant difference from 21oC/wet specimens, except EXA in G. Wet storage at higher temperatures (37oC and 50oC) adversely affected all the materials to a degree ranging from 40-60% (p<0.001). For dynamic testing, a significant difference was also found in material and testing condition groups, with a significant interaction between the two independent variables (p<0.001 for G1 and n*, p<0.01 for tan δ). Reduction in G1, and n* values, and increase in tan δ values were encountered at increased water temperatures. \r\n

Ana Pagan obtained the degree in Biology from University of Murcia. She has completed her PhD from the same University at the age of 28 years, with a research stay at the Division of Nutrition and Metabolic Diseases, LMU University, Munich, Germany. She works as a postdoctoral researcher in the Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA, Murcia, Spain), in the Department of Biotechnology, with premier biomaterials in tissue engineering.

Silk fibroin has been largely studied in tissue engineering due to its excellent physical and biological properties. Based on this regard, we have developed a new biomaterial consisting on high performance fibers produced directly from the silk glands of silkworms (Bombyx mori) called silkworm gut fibers (1). This novel biomaterial could be a potential solution in tendon and ligament repair, as these are very common injuries and the traditional surgical reconstruction including auto/allograft and ligament prostheses implants can involve several complications. With this aim, we have braided the silkworm gut fibers, in order to explore the possibility to create a consistent scaffold for ligament repair. \r\nThe production of the silkworm gut fibers is based on a traditional procedure that consists of immersion the silk glands in an acidic solution and a subsequent stretching. We evaluated the mechanical properties of 3 silkworm gut fibers weaved in three-strand braids. The biocompatibility assay was also performed by seeding bone marrow adult human mesenchymal stem cells (ahMSCs) on the braided material. 7, 14 and 21 days after seeding, adhesion and proliferation of the cells were studied by SEM and MTT assay, respectively.\r\nOur results showed a good and remarkable mechanical strength, with Young’s modulus values of 80 ± 20 MPa and an ultimate strength of 18 ± 2 MPa. Moreover, cell adhesion and proliferation were excellent, the cells appeared well spread and attached to the silkworm gut fibers surface, connecting to neighbouring cells and organizing a monolayer over the braided material at day 21 post-seeding (Figure 1).\r\nWe conclude that silkworm gut fibers combine good mechanical and biological characteristics to be considered a potential biomaterial in tissue engineering applications.\r\n

Margarita A.Khimich graduated Physics-Technical Faculty of National Research Tomsk State University. She earned a Bachelor of Technical Physics in 2013. She presented her master’s thesis devoted to alloys of Ti-Nb system and severe plastic deformation of Ti-Nb alloy in 2015. Now she is postgraduate student at National Research Tomsk State University and also researcher of the Laboratory of Physics of Nanostructured Biocomposites, Institute of Strength Physics and Materials Science. She takes part in the project of Russian Science Foundation devoted to selective laser melting of biocompatible Ti-Nb alloys.

Ti-Nb alloys are perspective for implants production. Titanium and its alloys have high elastic modulus (100-120 GPa). Due to their features alloys of Ti with (40-45) wt. % Nb have modulus close to that of bone. Selective laser melting (SLM) allows obtaining of low-modulus Ti-Nb alloys and items of complex shape. Change of SLM parameters affects the size of structural elements and phase composition of resulting product. The purpose of this study was to investigate influence of SLM parameter change on the structure and phase composition of Ti-(40-45) wt. % Nb alloy.\r\n3-D specimens obtained in Yurga Institute of Technology (Russia) on “VARISKAF-100MVS” installation were investigated. To obtain the alloy the composite powder of titanium and niobium was obtained by mechanical activation of titanium and niobium powders mixture in AGO-2C ball mill (AltSTU, Barnaul, Russia) and was layered on titanium substrate. After activation composite powder was annealed in vacuum at 500°C during one hour. The thickness of each layer was 0.05 mm. Melting process was carried out in Ar atmosphere. Specimens were formed with the laser beam of 80 W-power. The spot diameter was 150 µm, scanning step was 0.4 mm. As a changed parameter laser beam scanning velocity was selected. It was changed in the range 40-70 mm/sec with the step of 10 mm/sec.\r\nThe results of investigation have shown that the alloy obtained by SLM has an elemental composition of Ti-45 wt. % Nb. Powder is completely melted and crystallized during SLM. The structure is represented by two phases. They are the main β-solid solution of titanium and niobium and α\'\'-Ti containing Nb. The microstructure contains zones with fine and medium grains. Shrinkage and gas pores are observed in specimens.\r\nThe investigation was financially supported by Russian Science Foundation, project # 15-19-00191.\r\n

Antonio Abel Lozano-Pérez has his expertise in chemistry of the silk fibroin and in processing the silk to obtain nanoparticles for drug loading and delivery useful for nanomedicine. He has developed this nanoparticles after years of experience in research and develop, both in the University of Murcia and IMIDA institutions. He have BSc degrees in Biochemistry and Chemistry (University of Murcia, Spain) and gained a PhD in Chemistry (University of Murcia). In 2010 he gained a position as PhD researcher in the Biotechnology Department of the IMIDA (Murcia, Spain) to develop new applications of the silk fibroin nanoparticles. His research contract is partially supported (80%) by the ERDF/FEDER Program of the Region of Murcia (Ref:1420/01).

In the last decades several researchers have associated a flavonoid-rich diet with an increase in average life in Mediterranean area and a related reduction in the frequency of cardiovascular diseases. Up to date, multiple formulations with different encapsulation methods and carriers for Q have been described in order to improve the stability and bioavailability of flavonoids. This work describes how silk fibroin nanoparticles (SFNs) are capable of adsorbing and releasing quercetin and how their integrity is highly preserved when is adsorbed onto the nanoparticles, as confirmed by antioxidant activity assays. Quercetin loading onto SFNs was optimized in terms of quercetin/SFNs ratio (w/w), time of adsorption and solvent mixture. Quercetin-loaded silk fibroin nanoparticles (QSFNs) were characterized using the dynamic light scattering technique to measure the diameter (Z-Average) and Z-potential (). The size of loaded particles reached 171 ± 1 nm (PdI = 0.190) and were slightly bigger than the empty SFNs 139 ± 1 nm (PdI = 0.158), while the  potential of QSFNs in water shifted toward positive values, from –27.3 ± 0.4 mV in empty SFNs to –17.1 ± 2.4 mV in QSFNs. Protein corona formation onto SFNQs was lower when the loaded quercetin increased due the shielding effect of the flavonoid around the nanoparticles. The antioxidant activity against DPPH• showed that the Q loaded in QSFNs not only retains the antioxidant activity but also has a synergistic scavenging activity due the intrinsic antioxidant activity of the silk fibroin. Drug loading content (DLC) and encapsulation efficiency (EE) varied with the relation between Q and SFN in the loading solution reaching a maximum values of EE = 70% and DLC of 0.7%. The sustained release of Q was observed during the experiment both in phosphate buffer saline pH 7.4 and simulated intestinal fluid pH 6.8 with an overall cumulative release of 40% after 24h. SFNQs fluorescence can be detected in a L929 cell. The results point to SFNs as promising candidate for Q loading, transport and delivery with potential applications in nanomedicine, while retaining their nano-size and their antioxidant properties.

Dr. Salvador D. Aznar Cervantes, born on 22 January 1983, works as a researcher in the Department of Biotechnology, in the R&D Center in Biotechnology and Biomedicine, IMIDA (Murcia). He obtained his degree in Biology from the University of Murcia (2006), then he completed his doctoral thesis, working as a grant holder (FPI-INIA), under the direction of Dr. José Luis Cenis Anadón, in January 2013. During the development of his PhD, he researched on biotechnological and biomedical applications of the silk worm (Bombyx mori). This period was complemented with 3 successive visits (2010, 2011, 2012) to the Department of Chemical Engineering of Massachusetts Institute of Technology (MIT), where he also collaborated with Tufts University (Professor David L. Kaplan) and the Massachusetts General Hospital (Professor Robert Redmond).

New approaches to neural research require biocompatible materials capable to act as electrode structures or scaffolds in order to stimulate or restore the functionality of damaged tissues.\r\nGraphene is a conducting material introduced in the field of tissue engineering due to its good biocompatibility and potential applications in biomedicine [1]. Silk fibroin (SF) is also a well-known biocompatible material in itself that combines with graphene producing hybrid films formats [2-4], providing an excellent support for cell proliferation [5]. However, the use of electrospun mats seems to be a better choice due to the biomimetic configuration with an extracellular matrix. Therefore, the approach proposed in the present work explores the combination of reduced graphene oxide (rGO) adsorbed on SF mats in order to confer them electroconductive properties [6].\r\nPC-12 cell line was chosen for the study since these cells can be differentiated into a neuronal-like phenotype by exposing to NGF. The differentiation levels achieved with this treatment (SF/rGO/NGF) were compared (Fig.1) to the ones obtained in cells growing on: pure SF mats (SF), mats coated with rGO submitted to electrical stimulation (SF/rGO/ES) and mats coated with rGO without anyother stimulus (SF/rGO).\r\nThe method of production of these scaffolds barely alters the mechanical properties of pure SF mats. However, multiple benefits are obtained by means of the coating with rGO. In addition to the optimal viability detected in cells growing on all the produced materials, a clear improvement of adhesion and proliferation is exhibited in mats containing rGO. The stimulus provided by the rGO itself induces a significant differentiation level to neuronal-like phenotypes. However, the percentage of differentiation can be increased by means of the application of ES (100mV during 2h) or the treatment with NGF, being the neurite outgrowth more pronounced when electric currents are applied to the cell cultures.\r\n

Ali Can Özarslan completed bachelor degree at Yildiz Technical University, department of bioengineering in 2015. He continues his education as a graduate student at Yildiz Technical University, department of bioengineering. He has 2 research paper published by the international refereed journals and 5 papers published by the international scientific meetings. Topics of his interest are bone tissue engineering, biomaterials, bone tissue support materials.

Bone tissue support materials have biocompatibility, biodegradability and bioactivity properties that are made of various ceramics, polymers or both of ceramics and polymers which is called composites. The most interesting of them is bioactive glasses due to their excellent features. Bioactive glasses are osteoconductive and osteoinductive materials and when they implanted on bone, they connect to the bone tissue. They are generally used in order to fill bone defect and promote new bone formation because of their osteogenic cell stimulator and bioactivity properties. In recent years, bioactive glass materials which are used as bone in the form of block, granules, injectable or paste has increased significantly. These forms which are called support material make easier patient healing and surgical operation.\r\nIn this study, injectable bone tissue support materials based on bioactive glass-polymer composites were produced for bone tissue engineering applications. At different ratios of bioactive glass and alginate composites were prepared such as 1:1, 2:1; g:ml, respectively. All samples were characterized by Fourier Transform Infrared Spectroscopy (FT-IR) analysis before simulated body fluid (SBF) to understand structure of composites and after SBF to understand bioactivity properties of composites.\r\n

I am Patricia Ros Tárraga, and I am a Biotechnology graduated at Universidad Miguel Hernández of Elche (UMH). Nowadays, I am a pre-doctoral student at Universidad Católica San Antonio de Murcia (UCAM), and I am working in the design and development of new bioactive materials and their use in the field of bone tissue regeneration. I am studying the physical properties of Si-Ca-P-based scaffolds and their effect on the adult human Mesenchymal Stem Cells (ahMSC) behavior.

In the last few decades, life expectancy of the population has increased as a consequence of health improvements, increasing the incidence of bone problems, like fractures, osteoporosis and bone metastasis. Traditionally, these bone lesions are treated by reconstructive surgery, using autologous, allogeneic or xenogeneic implants, having the problems of lack of donated organs and tissues as well as the immune rejection. For this reason, the emergence of tissue engineering was necessary. This science studies how to achieve the regeneration of diseased tissues using scaffolds with appropriate physical and biological properties. Silicon (Si) is a trace element that enhances bone formation and maturation in the body. Therefore, in this work, an 85wt% C2S-15wt% TCP porous scaffold has been studied for \r\n \r\n\r\nfuture medical uses.\r\n\r\nThe porous scaffolds were produced by the polymer replication method using polyurethane sponges with open cells as a template. They were impregnated with an appropriated ceramic slurry and sintered. After obtaining the porous scaffold, ions release was performed to know their behavior in DMEM, cytotoxicity and metabolic activity assays were carried out to know their biocompatibility with ahMSC and, finally, FESEM images were obtained to observe the morphology of the ahMSC over the surface of the material.\r\n\r\nThe exchange of ions between the media and the material was good and the rest of experiments showed a low cytotoxicity and a good metabolic activity of the ahMSC, as well as a good morphology of the cells over the surface of the material at different times.\r\n\r\nWe can conclude that these scaffolds could be a good option for future uses in regenerative medicine, although more in vitro and in vivo experiments will be necessary to complete this study.\r\n

My name is Rubén Rabadán Ros, I am biologist by the University of Murcia (UMU) and I have a MSc degree in Molecular Biology and Biotechnology by the same university. Currently, I am a PhD student in Biomedical Sciences at Universidad Católica San Antonio, Murcia (UCAM), developing scaffolds based on the C2S-TCP phase diagram and their in vitro and in vivo study.\r\n\r\n

\r\nSilicon (Si) is a trace element that enhances bone formation and maturation in the body; thus apatite ceramics containing Si are expected to increase the speed of bony regeneration.\r\n\r\nThe mesenchymal stem cells from human bone marrow (ahMSCs) are a great promise for cell-based therapies by their ability to differentiate into osteoblast in certain microenvironments. The purpose of this study was to evaluate the effect of a well-characterized Nurse´s A-phase (7CaO•P2O5•2SiO2) ceramic compared to a control (tissue culture polystyrene-TCPS) on osteogenic differentiation of ahMSCs in vitro. Alizarin Red-S (AR-s) staining, alkaline phosphatase (ALP) activity, and collagen I (COLI) were evaluated. Also, field emission scanning electron microscopy (FESEM) images were acquired in order to visualise the morphology of the cells.\r\n\r\nThe entire surface was colonized after 28 days of culture in growth medium (GM). Osteoblastic differentiation markers were significantly enhanced in cells growing on Nurse´s A phase ceramic and cultured with osteogenic medium (OM), and cells acquired polygonal shape typical from osteoblasts, probably due to the role of silica to stimulate the differentiation of ahMSCs. Moreover, calcium nodules were formed under the influence of ceramic material.\r\n\r\nTherefore, it is predicted that Nurse´s A-phase ceramic would present high biocompatibility and good osteoconductivity, being a good candidate to be used as a biomaterial for bone tissue engineering.\r\n

Thangavel Ponrasu has completed his MSc., M. Phil. and Ph.D in Biochemistry. He has expertise in diabetic wound healing. During his Ph.D, he has gained hands on experience in toxicity evaluation in zebrafish embryos and screening medicinal plants for diabetic wound healing. He is very good in animal handling and surgical procedure to create full thickness wounds in rats. Currently, he is pursuing his post-doctoral research in the department of Biotechnology, IIT Madras, India from July 2014. During his post-doc, he is developing novel, inexpensive wound dressing materials to enhance diabetic wound healing. He has published 22 papers in peer reviewed journals so far. He has attended many national, international conferences to present his research findings. He is focusing on the development of inexpensive wound dressing materials to heal the diabetic wounds much faster.

Statement of the Problem: Diabetes mellitus (DM) is one of the major health concerns with increasing prevalence. Wounds in diabetic patients are slow to heal and persist for few months under proper wound care and management. Pathophysiology of impaired diabetic wound healing is still unclear and it is presumed that delayed healing is due to the persistence of prolonged inflammation and an inadequate angiogenic response. However, an ideal wound dressing materials can act as a protective barrier against pathogens, help in cell attachment, proliferation, migration and differentiation during wound healing process. Methodology: Fabrication of the reduced graphene oxide loaded isabgol (Isab) scaffolds (Isab/rGO) was prepared by freeze drying method using STMP crosslinking. Biocompatibility of the Isab/rGO scaffolds was carried out in NIH 3T3 fibroblast cells. Then, these scaffolds were used as a topical wound dressing material to assess the normal and diabetic wound healing efficacy using 2 × 2 cm2 full thickness open excision wounds in Wistar rats. Granulation tissue collected from wounds was used to evaluate the biochemical, biophysical, histopathology and immunohistochemistry analyses. Results: Isab/rGO scaffolds are biocompatible in NIH 3T3 L1 cells and it also showed significant antibacterial activity. Isab/rGO scaffolds treatment showed increased wound contraction (p < 0.05) compared to control and isab scaffold both in normal and diabetic wound healing. Period of epithelialization is also significantly reduced in isab/rGO scaffolds treated normal and diabetic wounds compared to isab and control. Histopathology and immunohistochemistry results also revealed that the isab/rGO scaffold dressing accelerated macrophage recruitment and neovascularization to heal the wounds faster. Conclusion & Significance: These results demonstrated that incorporation of rGO in isabgol can reduce the prolonged inflammation and enhance the wound healing by accelerating the neovascularization and collagen synthesis. Hence, isab/rGO scaffold could be an inexpensive wound dressing material for diabetic wound healing application.