Alcohol Glass Research Articles

Preparation, properties and in vitro osteogensis of self-reinforcing injectable hydrogel

As an attractive biomaterial for bone reconstruction, injectable biomaterials have many prominent characteristics such as good biocompatibility and bone-filling ability. However, there are weak as load-bearing scaffolds. In this study, polyvinyl alcohol (PVA) and bioactive glass (BAG) were interpenetrated into sodium alginate (SA) network to obtain self-enhanced injectable hydrogel. The optimum ratio of PVA/SA/BAG hydrogel was determined based on injectability, gelation time and chemical characterization. Results showed that the selected ratio had the shortest gelation time of 3.5min, and the hydrogel had a rough surface and good coagulation property. The hydrogel was capable of carrying 1kg of weight by mineralization for 14 d The compressive strength, compressive modulus, and fracture energy of the hydrogel reached 0.12MPa, 0.376MPa and 17.750kJ m−2, respectively. Meanwhile, the hydrogel had high moisture content and dissolution rate, and it was sensitive to temperature and ionic strength. Hydroxyapatite was generated on the hydrogel surface, and the hydrogel pores increased, and the pore size enlarged. The biocompatibility of PVA/SA/BAG hydrogel was analyzed using hemolysis and cytotoxicity assays. Results revealed its good biocompatibility with low hemolysis rate and no cytotoxicity to MC3T3-E1 cells. The hydrogel was also found to promote the differentiation of MC3T3-E1 cells with significantly increased in ALP activity and expression of relevant differentiation factors. In vitro mineralization assay showed an increase in calcium nodules and calcification area, indicating the ability of hydrogel to promote mineralization MC3T3-E1 cells. These findings indicated that PVA/SA/BAG hydrogel had potential uses in the field of irregular bone-defect repair due to its injectability, cytocompatibility, and tailorable functionality.

Tensile behavior of ultra‐high performance concrete reinforced with different hybrid fibers

AbstractSeventy eight dog‐bone shaped ultra‐high performance concrete (UHPC) tensile specimens were designed to study the effects of single steel fiber and hybrid steel fiber with polyolefin (PP) fiber, polyvinyl alcohol (PVA) fiber, glass fiber (GF), polyester (PET) fiber, and basalt fiber (BF) on the compressive strength, tensile strength, peak strain, and fracture energy of UHPC. The results showed that hybrid fiber reinforced UHPC had good toughness damage characteristics, which reflected the strengthening and toughening effects of different fibers. The tensile stress–strain curves of hybrid fiber reinforced UHPC could be divided into the rising section and softening section, and the softening section was significantly influenced by the type and volume content of fibers. Among the microfiber (PVA fiber, GF, and BF), GF had the most significant strengthening effect, PVA fiber had the best ability to improve the deformation of UHPC, and BF had the most significant effect on the improvement of fracture energy. Among macrofiber (PP fiber, PET fiber), PP fiber had a better ability to improve UHPC deformation than PET fiber, but both were lower than microfiber. When the total volume content of steel fiber and PVA fiber was 2.5%, the best toughening and crack resistance effect was achieved when the volume content of steel fiber was 1.5% and the volume content of PVA fiber was 1.0%. Combined with the experimental results, the UHPC tensile σ–ω curves of single steel fibers, hybrid steel–PVA fibers, and hybrid steel–PVA–PET fibers were established, and the predicted curves were in good agreement with the experimental curves.

Characteristics of Interfacial Shear Bonding Between Basalt Fiber and Mortar Matrix.

Basalt fibers have been adopted as reinforcements to improve mechanical performance of concrete materials and structures due to their excellent corrosion resistance, affordable cost, and environmental-friendly nature. While the reinforcing efficiency is significantly dependent on fiber–matrix interfacial properties, there is a lack of studies focusing on the bonding behavior of basalt fibers in the mortar matrix. In this paper, a series of experiments were carried out to investigate the characteristics of single basalt fiber pulled out from the mortar matrix. Three embedment lengths and three types of mortar strength were considered. As references, the pull-out behavior of single polyvinyl alcohol (PVA) fiber and glass fiber in mortar matrix were also tested for comparison. Results from the pull-out test revealed that the average bonding strength is more effective than the equivalent shear bonding strength to illustrate the interfacial bond behavior of single basalt fiber in mortar matrix, which can be improved by either longer embedment length or the stronger mortar matrix. Finally, the tensile and compressive strengths of basalt/PVA/glass fiber-reinforced concrete (FRC) were measured to investigate the influence of interfacial shear bonding strengths. It was shown that, while PVA fiber developed the highest shear bonding strength with mortar, the basalt fiber exhibited the best reinforcing efficiency of FRC.

Photofunctional Cyclometalated Iridium(III) Polypyridine Complexes Bearing a Perfluorobiphenyl Moiety for Bioconjugation, Bioimaging, and Phototherapeutic Applications.

In this article, we report the design, synthesis, and characterization of a series of cyclometalated iridium(III) polypyridine complexes containing a perfluorobiphenyl (PFBP) moiety [Ir(N^C)2(bpy-PFBP)](PF6) (bpy-PFBP = 4-(S-(perfluoro-(1,1'-biphenyl)-4-yl)-N-mercaptoethylaminocarbonyloxymethyl)-4'-methyl-2,2'-bipyridine; HN^C = 2-phenylpyridine (Hppy) (1a), 2-(4-hydroxymethylphenyl)pyridine (Hppy-CH2OH) (2a), 2-((1,1'-biphenyl)-4-yl)pyridine (Hpppy) (3a), 2-((4'-hydroxymethyl-1,1'-biphenyl)-4-yl)pyridine (Hpppy-CH2OH) (4a), 2-phenylquinoline (Hpq) (5a), 2-(4-hydroxymethylphenyl)quinoline (Hpq-CH2OH) (6a)). Their PFBP-free counterparts [Ir(N^C)2(bpy-C4)](PF6) (bpy-C4 = 4-(N-n-butylaminocarbonyloxymethyl)-4'-methyl-2,2'-bipyridine; HN^C = Hppy (1b), Hppy-CH2OH (2b), Hpppy (3b), Hpppy-CH2OH (4b), Hpq (5b), Hpq-CH2OH (6b)) were also prepared for comparison studies. Upon irradiation, all the complexes displayed intense and long-lived greenish-yellow to orange luminescence in solutions under ambient conditions and in low-temperature alcohol glass. Reactions of the PFBP complexes with peptides containing the FCPF sequence via the π-clamp-mediated cysteine conjugation afforded luminescent peptide conjugates that exhibited rich photophysical properties. Using complex 3a as an example, we demonstrated that the conjugation of complexes to organelle-targeting peptides is an effective means to modulate their intracellular localization behavior, which was further shown to be important to their performance in photodynamic therapy. The results of this work will contribute to the development of photofunctional transition metal complexes as theranostic agents.

Viscoelasticity, mechanical properties, and in vivo biocompatibility of injectable polyvinyl alcohol/bioactive glass composite hydrogels as potential bone tissue scaffolds

An injectable composite hydrogel composed of polyvinyl alcohol (PVA) and bioactive glass (BG) particles were synthesized by a physical crosslinking approach. The morphology, mechanical properties, and viscoelasticity of the PVA/BG composite hydrogel were characterized. Scanning electronic microscopy (SEM) showed uniform and homogeneous distribution of BG particles throughout the composite hydrogel. The incorporation of 2.5 wt% of BG particles in the composite hydrogel formulations, enhanced the static compressive strength and static elastic modulus by 325% and 150%, respectively. The storage molds (G′) was greater than the loss modules (G′′) at all the frequency range studied, which revealed a self-standing elastic composite hydrogel with a smooth injectability. The PVA/BG composite hydrogel was also implanted subcutaneously in the dorsal region of adult male rats. After 4 weeks of implantation, no inflammatory cells were seen within and around the implant, which indicated that the composite hydrogel was biocompatible. The properties of the synthesized injectable PVA/BG composite hydrogel demonstrate its capability toward bone regeneration.

Synthesis and characterization of dextran ester derivatives and their adhesive properties

Polysaccharides are promising renewable alternatives to petroleum-based plastics, and are high-value-added materials in various industries. In this work, we synthesized dextran (α-1,6-glucan) ester derivatives substituting acyl groups with different carbon numbers from acetate to laurate. We found that the thermal stability of dextran was improved by esterification. Moreover, using differential scanning calorimetry and X-ray diffraction, we revealed that dextran ester derivatives were amorphous. Self-standing, transparent, solvent-cast films of dextran ester derivatives were prepared. Dextran ester derivatives adhered to various materials, including polyvinyl alcohol (PVA) films, wood, glass, and aluminum. In addition, the adhesive interfaces were transparent, which is important for practical applications. The adhesive strength for PVA films increased with concentration, exceeding the breaking strength of the PVA film at 0.3 g/mL. Moreover, dextran valerate and dextran hexanoate behaved as hot-melt-type adhesives. These results demonstrate the potential of dextran ester derivatives as biomass-based adhesives.

Flexural Performance Evaluation of Fiber-Reinforced Concrete Incorporating Multiple Macro-Synthetic Fibers

Fiber-reinforced concrete (FRC) is a promising construction material mainly because of the crack-controlling mechanisms that discrete fibers can impart to inherently brittle concrete. Macrofibers, in particular, have been proven effective for providing post-crack ductility and toughness, while synthetic fibers are a promising solution to avoid corrosion-related durability issues. To assess the performance enhancement provided by macro-synthetic concrete fibers, this study performs flexural tests on FRC beams containing three different types of macro-synthetic fibers. The selected fibers include polypropylene (PP), polyvinyl alcohol (PVA), and alkali-resistant glass (ARG) macrofibers mixed at volume fractions of 0.5%, 1.0%, and 1.5%. Static and dynamic fresh properties are monitored using the vibrating Kelly ball (VKelly) test. Beam specimens are then placed under a third point bending configuration, as per ASTM C1609 Standard, to measure load versus mid-span deflection. Strength and toughness parameters are derived from the load–deflection data to assess the flexural performance of the FRC composite systems under consideration. The parameters of interest include first peak strength (pre-crack flexural strength) and post-crack residual strength and toughness provided by fiber addition. Of the mixtures tested, ARG fiber mixtures show the highest residual strength and toughness values, followed by PP and PVA fiber mixtures. ARG fibers produce the most workable mixtures at all fiber volumes, while PVA fibers show a tendency to encounter dispersion issues at higher volume doses. The outcome of this study is expected to facilitate the selection of fibers by giving insight into their relative contribution to fresh and hardened flexural properties of FRC.

Synthetic Three-Dimensional Scaffold for Application in the Regeneration of Bone Tissue

Bone tissue engineering aims to use biodegrade able scaffolds to replace damaged tissue. This scaffold must be gradually degraded and replaced by tissue as similar as possible to the original one. In this work a hybrid porous scaffold containing chitosan, polyvinyl alcohol and bioactive glass was successfully obtained and subsequently characterized by scanning electron microscopy. The scaffold presented satisfactory pore size range and open interconnected pores, which are essential for tissue ingrowth. A cytotoxicity assay showed that this biomaterial allows adequate cell viability, so that it was considered suitable for an in vivo experiment. Promising results were obtained with the implant of the scaffold in an experimental model of a New Zealand rabbit femur bone lesion. Clinical and biochemical parameters measured such as complete blood count, total serum proteins, albumin, alanine aminotransferase and aspartate aminotransferase were similar between animals in the control group at all time periods studied. Histological and histometric studies showed that the scaffold was coated with a cement-like substance, exhibiting many areas of mineralized structures. Very few osteocyte-like cells or lining-like cells were found inside the amorphous mineralized deposit. In vivo results allow us to consider this scaffold as a promising biomaterial to be applied in bone tissue engineering.

Study on New Hydrid Engineered Cementitious Composites for Structural Application

This paper investigates about the effects of polyvinyl alcohol (PVA) fibres, polypropylene fibers, steel and glass fibers on the workability, compressive and tensile strength of engineered cementitious composite (ECC). The key parameter discussed in this study is the reinforcing index. Strength increases in the member when mixed with PVA, PP, Glass and Steel fibers.higher the ECC, higher the strain capacity of any member. Cubes and dog legged specimens are casted for various mix proportion, tests are carried out. Results showed that hybrid ECC mix attained the reasonable improvement in the mechanical properties.

Fluid preservation: a comprehensive reference

Introduction Acknowledgements Part I. Fluid Preservation Techniques and Collections Chapter 1. History of Fluid Preservation Fluid Preservation in the Ancient World History of Ethyl Alcohol Origin of the Name Alcohol Glass Containers The Discovery of Preservation of Specimens in Ethyl Alcohol Early Instructions for Preserving Specimens in Fluids Later Instructions for Preserving Specimens in Fluids Fluid Preserved Collections Other Fluid Preservatives Summary Chapter 2. Fixation Fixation Formaldehyde Origin of the Names Formaldehyde, Formol, and Formalin Commercial Formaldehyde Formaldehyde as a Fixative and Preservative Fixative pH Range Narcotization Fixatives for Botanical Specimens Temperature, Time, and Rates of Penetration of Fixatives The Penetration-Fixation Paradox Lipids and Fixation Formaldehyde and Field Work Paraformaldehyde Post-Formaldehyde Fixation Washing Unwanted Effects of Formaldehyde Gluteraldehyde Aldehyde Safety Alternative and Proprietary Fixatives Chapter 3. Preservation Preservation without Fixation Freezing Transfer between Fluids Preservative Quality Old Fluid Preservatives Botanical Use of Fluid Preservation Glycerin Isopropyl Alcohol Fluid Preservation for DNA Extraction Evaporation Clearing and Staining Anatomical and Histological Fluid Preparations Mounting Specimens Inside Containers Glycol, Phenol, and Phenoxetol as Preservatives Novec Fluid Mineral Oil Universal Fixatives Criteria for Evaluating Alternative Fixative and Preservative Fluids Chapter 4. Effects of Fixatives and Preservatives on Specimens Changes in Body Dimensions and Biomass Changes in Color Solvent Extraction in Fixatives and Preservatives Chapter 5. Managing Fluid Preserved Collections Identification of Fluid Preservatives Checking Fluid Concentration Re-Use of Old Alcohol pH of Preservative Solutions Preparing Fixatives and Preservatives Containers and Seals Alternatives to Glass Containers Labeling The Storage Environment Topping Up and Replacing Preservatives Why do Closures Fail? Bacterial and Fungal Growth in Fluid Collections-Detection and Remediation Rehydration of Fluid Preserved Specimens Moving Collections Exhibition of Fluid Preserved Specimens Dealing with Old Containers and Old Specimens Repair of Damaged Fluid Preserved Specimens Health and Safety Fire Prevention Formaldehyde Safety Chapter 6. Fluid Preserved Collections as Cultural Patrimony Why Preserve Specimens in Fluid? The Fluid Preserved Human Fond Memories of Fluid Preservation Fluid Preservation in Visual Art Fluid Preservation in Literature Fluid Preservation in Film Fluid Preservation in Popular Culture The Aesthetics of Fluid Preservation Part II. Literature in this Field Chapter 7. Literature Cited. Chapter 8. Literature Reviewed but Not Cited Part III. Reference Tables Table 1. Fluid preservation techniques. Table 2. Timeline of milestones in published fluid preservation techniques. Table 3. Tissue matrix types. Table 4. Proprietary fixatives (based on manufacturer's MSDS, advertisements, and published analyses). Table 5. Narcotizing agents. Table 6. Disinfectant mechanisms of some preservatives (based in part on Volk and Wheeler 1984). Table 7. Summary of factors that affect the long-term usefulness of fluid preserved specimens (after Simmons 2002). Table 8. Timeline of the known introduction of chemicals in fluid preservation. Table 9. Anatomical fixation and preservation techniques. Table 10. Clearing and staining techniques. Table 11. Disinfectant mechanisms of some preservatives (based in part on van Dam 2003). Table 12. Criteria for identifying alternative preservative fluids (based in part on van Dam 2003). Table 13. Summary of fixative and preservative induced changes in invertebrates. Table 14. Summary of fixative and preservative induced changes in invertebrates by taxonomic group. Table 15. Summary of fixative and preservative induced changes in vertebrates by taxonomic group. Table 16. Summary of fixative and preservative induced changes in vertebrates by taxonomic group. Table 17. Proprietary preservatives (based on manufacturer's MSDS, advertisements, and published analyses). Table 18. Summary of published fluid concentration and pH testing of fluid preserved collections. Table 19. Characteristics of containers for fluid preserved specimens (based on Simmons 2002). Table 20. Oxygen permeablility of container materials. Table 21. Published recommendations for label substrates and inks. Table 22. Rehydration techniques for fluid preserved specimens. Table 23. Treatments and practices that are not recommended for fluid preserved specimens. Appendix Index About the Author

Preparation and in vitro characterization of electrospun 45S5 bioactive glass nanofibers

Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, 45S5 bioactive glass fibers were prepared through sol–gel processing and electrospinning technique. A precursor solution containing poly vinyl alcohol and bioactive glass sol was used to produce fibers. The mixture was electrospun at a voltage of 20kV by maintaining tip to a collector distance of 8cm. The fibers with an average diameter of 337±81nm (before calcination) were successfully obtained. Results showed that the crystalline phase of the fibers was largely influenced by the calcination temperature. Hydroxyapatite formation on calcined 45S5 fibers was investigated in simulated body fluid (SBF) using different fiber/SBF (F/S) ratios (0.5, 1, 2 and 10mg/ml) at 37°C. When immersed in SBF, conversion to a calcium phosphate material showed a strong dependence on the F/S ratio. At high solid concentration (10mg/ml), surface of the fibers could not be converted to the HA-like material in SBF after 30 days. At lower solid concentrations (2, 1 and 0.5mg/ml) an amorphous calcium phosphate layer formation was observed followed by the conversion to hydroxyapatite.

Four-component fluorescence of trans-1,2-di(1-methyl-2-naphthyl)ethene at 77 K in glassy media. Conformational subtleties revealed.

The vibronic structure of the fluorescence spectrum of trans-1,2-di(1-methyl-2-naphthyl)ethene (t-1,1) in methylcyclohexane (MCH) solution at room temperature was expected to become better defined upon cooling of the solution to 77 K. Instead, a broad, λexc-dependent fluorescence spectrum was observed in the glassy medium. Vibronically structured t-1,1 fluorescence spectra were obtained in the MCH glass only upon irradiation at the long-λ onset of the absorption spectrum. The application of singular value decomposition with self-modeling on the fluorescence spectral matrices of t-1,1 allowed their resolution into major and minor pairs of vibronically structured spectra that are assigned to two structural modifications of each of two relative orientations of the 1-methyl-2-naphthyl moieties. The difference between the two structures in each pair lies in the direction of rotation of each naphthyl group away from the plane of the olefinic bond. A complex but different conformer distribution is also responsible for the fluorescence spectra of t-1,1 in 5:5:2 (v/v/v) diethyl ether/isopentane/ethyl alcohol (EPA) glass at 77 K. The conformer distributions are also sensitive to the rate of cooling used in glass formation. Conformer distributions based on predicted small energy differences from gas-phase theoretical calculations are of little value when applied to volume-constraining media. The photophysical and photochemical properties of the analogues of the other two conformers of trans-1,2-di(2-naphthyl)ethene, trans-1-(1-methyl-2-naphthyl)-2-(3-methyl-2-naphthyl)ethene (t-1,3) and trans-1,2-di(3-methyl-2-naphthyl)ethene (t-3,3), were determined in solution. However, it is the calculated geometries and energy differences of the t-1,1 conformers [DFT using B3LYP/6-311+G(d,p)] that are essential guides to the interpretation of the experimental results.

Effect of ciprofloxacin incorporation in PVA and PVA bioactive glass composite scaffolds

Scaffolds are implants used to deliver cells, drugs, and genes into the body in a local controlled release pattern which offers many advantages over systematic drug delivery. Composite scaffolds of polyvinyl alcohol (PVA) and quaternary bioactive glass (46S6 system) with different ratios of glass contents were prepared by the lyophilisation technique. The broad spectrum antibiotic ciprofloxacin (Cip) was impregnated to the scaffold during the fabrication in a concentration of 5, 10 and 20%. Biodegradation rate and in-vitro mineralization of the prepared scaffolds were performed by soaking the scaffolds in simulated body fluid (SBF). Phase identification, microstructure, porosity, bioactivity, mechanical properties and drug release pattern in PBS were characterized by XRD, SEM coupled with EDS, Hg-porosimeter, inductively coupled plasma-optical emission spectroscopy (ICP-OES), universal testing machine, fourier transform infrared (FTIR) and UV-spectrophotometer, respectively. A porous scaffold has been obtained with porosity up to 85%. By increasing the glass contents in the prepared scaffold the porosity and the degradation rate decrease however, the compressive strength was enhanced. A sustained drug release pattern was observed with a quasi-Fickian diffusion mechanism. The formulated ciprofloxacin loaded porous polyvinyl alcohol scaffold gave an acceptable physicochemical properties and was able to deliver the drug in a prolonged release pattern which offers a distinguish treatment for osteomylitis as well as local antibacterial effect.

Effect of infection control aids on polymerization inhibition of polyvinyl siloxane impression materials – An invitro study

ObjectivesTo evaluate the effect of infection control aids (latex gloves in contact with surfactants) upon polymerization during manipulation of different types of polyvinyl siloxane impression materials. MaterialsThree types of polyvinyl siloxane impression materials, (Examix, Affinis and Aquasil Ultra) were tested under four surface treatment conditions (alcohol, water, soap/water and unexposed glass surface as control) with two types of latex gloves (powdered and powder free). This resulted in a 3 × 4 × 2 experimental design of 24 cells with 20 specimens each. MethodsPVS impression material was expressed onto the glass surface conditioned with surfactant resulting in specimens (n = 20). The specimens were lifted from the testing surface at the applicable time, and the contact areas were examined independently by 2 of the authors to subjectively determine whether polymerization inhibition had occurred. Polymerization inhibition frequency was calculated for each group, and chi-square analysis and fissures exact test were used to determine whether there was a statistically significant relationship between polymerization inhibition in any of the study conditions (P < 0.05). ResultsThe results of this data showed significant increase in the polymerization inhibition of Examix and Affinis along with glove/alcohol combination. Comparison of the powdered/powder free glove groups found that there is no significant difference between these groups. Conclusion/clinical significanceUse of latex gloves along with alcohol should be avoided (simulation can happen during clinical practice) while manipulating polyvinyl impression materials.

Fabrication, Characterization and Drug Release of Ciprofloxacin Loaded Porous Polyvinyl Alcohol/Bioactive Glass Scaffold for Controlled Drug Delivery

Composite scaffolds of Polyvinyl Alcohol (PVA) and/or quaternary bioactive glass (46S6 system) containing 5, 10 and 20 wt % ciprofloxacin were prepared by lyophilisation technique. The porosity of the prepared scaffolds was measured by liquid displacement, Hg-porosimeter and SEM. The structure and the nature of chemical bonds between atoms were examined by XRD and FTIR. They confirmed the incorporation of ciprofloxacin into the scaffolds. Biodegradation rate and drug release behaviour were conducted in Phosphate Buffer Saline (PBS) at pH 7.4. A porous scaffold has been obtained with porosity up to 85%. By increasing the glass contents and drug concentration in the prepared scaffold the porosity and the degradation rate decrease however, the compressive strength was enhanced. A sustained drug release pattern was observed from the optimized scaffold with a quasi-Fickian diffusion mechanism and it was able to deliver the drug in a prolonged release pattern which offers a distinguish treatment for osteomylitis as well as local antibacterial effect.

Hybrid Matrix Grafts to Favor Tissue Regeneration in Rabbit Femur Bone Lesions

At present, typical approaches employed to repair fractures and other bone lesions tend to use matrix grafts to promote tissue regeneration. These grafts act as templates, which promote cellular adhesion, growth and proliferation, osteoconduction, and even osteoinduction, which commonly results in de novo osteogenesis. The present work aimed to study the bone-repairing ability of hybrid matrixes (HM) prepared with polyvinyl alcohol (PVA) and bioactive glass in an experimental rabbit model. The HM were prepared by combining 30% bioactive glass (nominal composition of 58% SiO2 -33 % CaO - 9% P2O5) and 70% PVA. New Zealand rabbits were randomly divided into the control group (C group) and two groups with bone lesions, in which one received a matrix implant HM (Implant group), while the other did not (no Implant group). Clinical monitoring showed no altered parameters from either the Implant or the no Implant groups as compared to the control group, for the variables of diet grades, day and night temperatures and hemograms. In the Implant group, radiologic and tomographic studies showed implanted areas with clean edges in femoral non-articular direction, and radio-dense images that suggest incipient integration. Minimum signs of phlogosis could be observed, whereas no signs of rejection at this imaging level could be identified. Histological analysis showed evidence of osteo-integration, with the formation of a trabecular bone within the implant. Together, these results show that implants of hybrid matrixes of bioactive glass are capable of promoting bone regeneration.

Luminescent Cyclometalated Iridium(III) Polypyridine Di-2-picolylamine Complexes: Synthesis, Photophysics, Electrochemistry, Cation Binding, Cellular Internalization, and Cytotoxic Activity

A series of luminescent cyclometalated iridium(III) polypyridine complexes containing a di-2-picolylamine (DPA) moiety [Ir(N^C)(2)(phen-DPA)](PF(6)) (phen-DPA = 5-(di-2-picolylamino)-1,10-phenanthroline) (HN^C = 2-phenylpyridine, Hppy (1a), 2-(4-methylphenyl)pyridine, Hmppy (2a), 2-phenylquinoline, Hpq (3a), 4-(2-pyridyl)benzaldehyde, Hpba (4a)) and their DPA-free counterparts [Ir(N^C)(2)(phen-DMA)](PF(6)) (phen-DMA = 5-(dimethylamino)-1,10-phenanthroline) (HN^C = Hppy (1b), Hmppy (2b), Hpq (3b), Hpba (4b)) have been synthesized and characterized, and their photophysical and electrochemical properties investigated. Photoexcitation of the complexes in fluid solutions at 298 K and in alcohol glass at 77 K resulted in intense and long-lived luminescence. The emission of the complexes has been assigned to a triplet metal-to-ligand charge-transfer ((3)MLCT) (dπ(Ir) → π*(N^N)) or triplet intraligand ((3)IL) (π → π*) (N^C) excited state and with substantial mixing of triplet amine-to-ligand charge-transfer ((3)NLCT) (n → π*) (N^N) character, depending on the identity of the cyclometalating and diimine ligands. Electrochemical measurements revealed an irreversible amine oxidation wave at ca. +1.1 to +1.2 V vs saturated calomel electrode, a quasi-reversible iridium(IV/III) couple at ca. +1.2 to +1.6 V, and a reversible diimine reduction couple at ca. -1.4 to -1.5 V. The cation-binding properties of these complexes have been studied by emission spectroscopy. Upon binding of zinc ion, the iridium(III) DPA complexes displayed 1.2- to 5.4-fold emission enhancement, and the K(d) values determined were on the order of 10(-5) M. Job's plot analysis confirmed that the binding stoichiometry was 1:1. Additionally, selectivity studies showed that the iridium(III) DPA complexes were more sensitive toward zinc ion among various transition metal ions examined. Furthermore, the cytotoxicity of these complexes toward human cervix epithelioid carcinoma cells have been studied by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide assay and their cellular-uptake properties by inductively coupled plasma mass spectrometry and laser-scanning confocal microscopy.

Luminescent cyclometallated iridium(iii) bis(quinolylbenzaldehyde) diimine complexes—synthesis, photophysics, electrochemistry, protein cross-linking properties, cytotoxicity and cellular uptake

Four new luminescent cyclometallated iridium(III) bis(quinolylbenzaldehyde) diimine complexes [Ir(qba)(2)(N⁁N)](PF(6)) (Hqba = 4-(2-quinolyl)benzaldehyde, N⁁N = 2,2'-bipyridine, bpy (1); 1,10-phenanthroline, phen (2); 3,4,7,8-tetramethyl-1,10-phenanthroline, Me(4)-phen (3); 4,7-diphenyl-1,10-phenanthroline, Ph(2)-phen (4)) have been synthesised and characterised, and their electronic absorption, emission and electrochemical properties investigated. The X-ray crystal structures of complexes 1 and 2 have been determined. Upon irradiation, complexes 1-4 exhibited intense and long-lived orange-yellow emission in fluid solutions at 298 K and in alcohol glass at 77 K. The emission has been assigned to a triplet intra-ligand ((3)IL) excited state associated with the qba ligand, probably with mixing of some triplet metal-to-ligand charge-transfer ((3)MLCT) (dπ(Ir) →π*(qba)) character. Reductive amination reactions of complexes 1-4 with the protein bovine serum albumin (BSA) afforded the bioconjugates 1-BSA-4-BSA, respectively. Upon photoexcitation, these bioconjugates displayed intense and long-lived (3)MLCT (dπ(Ir) →π*(N⁁C)) emission in aqueous buffer at 298 K. The cross-linked nature of the Ir-BSA bioconjugates has been verified by SDS-PAGE. Additionally, the cytotoxicity of the complexes towards human cervix epithelioid carcinoma (HeLa) cells has been examined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assays, and the cellular uptake of complex 4 has been investigated by laser-scanning confocal microscopy and flow cytometry.

Investigation into microstructural properties of fluorapatite Nd-YAG laser clad coatings with PVA and WG binders

Biomedical implants are generally coated with a thin layer of hydroxyapatite (HA) using a plasma spraying or pulsed laser deposition method. However, the bonding strength between the coating layer and the substrate is relatively low. Moreover, the high temperature of the deposition process causes a structural instability of the HA, and therefore degrades its bioactivity and reduces the service life of the coating layer following implantation. Accordingly, the present study replaces HA with fluorapatite (FA) as the coating material, and examines the effects of two different binders, namely polyvinyl alcohol (PVA) and water glass (WG), on the properties of FA coatings deposited on Ti–6Al–4V substrates using an Nd-YAG laser cladding process. Scanning electron microscopy (SEM) observations reveal that the FA coating has a coral- and dendrite-like structure when mixed with the PVA binder, but a pure dendrite-like structure when mixed with the WG binder. In addition, the Ca/P value of the WG-based FA coating is significantly higher than that of the PVA-based coating. Fluorapatite, Al 2O 3, CaTiO 3 and Ca 3(PO 4) 2 phases are observed in both coating layers. However, the XRD analysis results indicate that the microstructure of the WG sample is dominated by Ca 3(PO 4) 2 phase while that of the PVA sample is dominated by FA. After soaking in SBF, it was observed that the specimen produced with PVA binder or less laser output power possessed a better apatite induction ability.

Luminescent Polypyridinerhenium(I) Bis‐Biotin Complexes as Crosslinkers for Avidin

AbstractTwo novel luminescent polypyridinerhenium(I) bis‐biotin complexes [Re(NN)(CO)3(pyridine)](CF3SO3) {NN = 4,4′‐bis{[2‐(biotinamido)ethyl]aminocarbonyl}‐2,2′‐bipyridine, bpyC2B2 (1), 4,4′‐bis[(2‐{[6‐(biotinamido)hexanoyl]amino}ethyl)aminocarbonyl]‐2,2′‐bipyridine, bpyC2C6B2 (2)} and their biotin‐free counterpart [NN = 4,4′‐bis(n‐butylaminocarbonyl)‐2,2′‐bipyridine, bpyC4 (3)] have been synthesized and characterized. Upon irradiation, all the complexes exhibited triplet metal‐to‐ligand charge‐transfer (3MLCT) emission in fluid solutions at room temperature and alcohol glass at 77 K. The avidin‐binding properties of the bis‐biotin complexes 1 and 2 have been studied by 4′‐hydroxyazobenzene‐2‐carboxylic acid (HABA) assays, emission titrations, and dissociation assays. The potential use of the complexes as signal amplifiers for heterogeneous recognition assays has been demonstrated using avidin‐coated microspheres and one of the complexes. Additionally, the cytotoxicity of these rhenium(I) complexes towards the human cervix epithelioid carcinoma (HeLa) cell line has been evaluated by 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyltetrazolium bromide (MTT) assays. Furthermore, the cellular uptake of the complexes has been examined by laser‐scanning confocal microscopy. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)