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Although guided tissue regeneration (GTR) is a useful tool for regenerating lost tissue as bone and periodontal tissue, a biocompatible membrane capable of regenerating large defects has yet to be discovered. This study aimed to characterize the physicochemical properties and biological compatibility of polycaprolactone (PCL) membranes associated with or without nanostructured hydroxyapatite (HA) (PCL/HA) and Zn-doped HA (PCL/ZnHA), produced by electrospinning. PCL, PCL/HA, and PCL/ZnHA were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). Nanoparticles of HA or ZnHA were homogeneously distributed and dispersed inside the PCL fibers, which decreased the fiber thickness. At 1 wt% of HA or ZnHA, these nanoparticles acted as nucleating agents. Moreover, HA and ZnHA increased the onset of the degradation temperature and thermal stability of the electrospun membrane. All tested membranes showed no cytotoxicity and allowed murine pre-osteoblast adhesion and spreading; however, higher concentrations of PCL/ZnHA showed less cells and an irregular cell morphology compared to PCL and PCL/HA. This article presents a cytocompatible, electrospun, nanocomposite membrane with a novel morphology and physicochemical properties that make it eligible as a scaffold for GTR.

The aim of this study was to analyze the biological behavior and osteogenic potential of nanostructured hydroxyapatite microspheres substituted with strontium (nHASr). Therefore, twenty adult male Wistar rats were randomly distributed into two groups: GnHASr – critical bone defect filled with nHASr microspheres; e CG (control group) – critical bone defect without implantation of biomaterial; evaluated at the biological points of 30 and 60 days. The collected specimens were processed and stained with hematoxylin-eosin (HE) and Masson-Goldner trichrome (TG) and examined by light microscopy. Posteriorly, they were analyzed histomorphometrically to measure the percentage of neoformed osteoid matrix (%OM). In both groups studied, at all biological points, deposition of reparative osteoid matrix (OM) was observed near the bone edges; discrete chronic inflammatory response; connective tissue formation and neovascularization in the residual area of the defect. In the GnHASr, in the two evaluated periods, the deposition of OM was also noticed, both around and inside the microspheres. At 60 days, an area of 7.54% of OM deposition in relation to the total defect area was evidenced in the GnHASr, while in the CG this value was 6.80%. It is concluded that the nHASr microspheres evaluated were biocompatible, biodegradable, bioresorbable, bioactive and osteoconductive. In both groups, the formation of neomineralized tissue occurred in a limited way, which indicates that the concentration of metal used in the replacement did not favor greater osteogenic potential for the biomaterial. The evaluated biomaterial it's adequate for use as a filling material.

Hydroxyapatite (HA) is a biomaterial widely used in biomedical applications. Many studies have shown that ionic substituents can be incorporated into HA to produce a mineral composition more similar to natural bone tissue with more favorable biological characteristics for application in bone regeneration. However, its potentially toxic effects need to be evaluated before full approval for human use. For this purpose, an embryotoxicity test was performed on zebrafish according to OECD guideline 236. Zebrafish embryos were exposed to 1 or 3 microspheres of alginate containing nanoparticles of HA and carbonate (CHA), strontium (SrHA), and zinc-substituted HA (ZnHA) from 4 to 120 h post-fertilization (hpf). Lethality and developmental endpoints were evaluated. In addition, larval behavior at 168 hpf was also analyzed to observe whether biomaterials adversely affect optomotor and avoidance responses (neurotoxicity), as well as the oxidative stress pattern through qPCR. After 120 h exposure to all microspheres with different patterns of crystallinity, porosity, nanoparticle size, surface area, and degradation behavior, there was no mortality rate greater than 20%, indicating the non-embryotoxic character of these biomaterials. All experimental groups showed positive optomotor and avoidance responses, which means that embryo exposure to the tested biomaterials had no neurotoxic effects. Furthermore, larvae exposed to one SrHA microsphere showed a better optomotor response than the control. Furthermore, the biomaterials did not change the pattern of mRNA levels of genes related to oxidative stress even after 120 hpf. The growing number of new HA-based biomaterials produced should be accompanied by increased studies to understand the biosafety of these compounds, especially in alternative models, such as zebrafish embryos. These results reinforce our hypothesis that ion-substituted HA biomaterials do not impose toxicological effects, cause development and neuromotor impairment, or increase oxidative stress in zebrafish embryos being useful for medical devices and in the process of bone regeneration.

Hydroxyapatite (HA), Ca 10 (PO 4 ) 6 (OH) 2 , is a key material used to manufacture thin, bioactive coatings on metal implants for hard tissue regeneration. Technical challenges in their fabrication include control of the coating structure and chemical composition, as well as managing surface activation via ionic substitution. In this study, 15 – 216 nm-thick zinc-doped HA (ZnHA) thin films were grown via magnetron sputtering at room temperature. The effect of substituting Zn 2+ for Ca 2+ on the ultrastructures of the HA films was analyzed during several stages of film growth. Infrared vibrational scattering scanning near-field optical microscopy (s-SNOM) using the ultra-broad-band IR beam from synchrotron radiation was compared with Fourier transform infrared spectroscopy in attenuated total reflectance (FTIR/ATR) to reveal the close relationships between local topography and the chemical compositions of the film surface and the bulk of the film. The energy delivered via ionic bombardment induced the formation of complex structures: island-shaped nanoparticles of amorphous zinc-doped calcium phosphate, coalescent islands, disordered non-stoichiometric ZnHA nanoparticles, and long-range structures of nearly stoichiometric and crystalline ZnHA. Grazing incidence X-ray diffraction (GIXRD) from synchrotron radiation, X-ray photoelectron spectroscopy (XPS), focusing ion beam (FIB), and high-resolution transmission electron microscopy (HRTEM) confirmed Zn substitution into the HA lattice. Zinc was distributed homogeneously within the film structure (1.6 at%) but its concentration increased slightly on the film surface. The bulk of the film consisted of crystalline, columnar ZnHA domains oriented perpendicular to the substrate surface while the regions near the film/substrate interface were preferentially disordered and non-stoichiometric.

We present a detailed step-by-step approach for the low-cost production and surgical implantation of cranial prostheses, aimed at restoring aesthetics, cerebral protection, and facilitating neurological rehabilitation. This protocol uses combined scan computed tomography (CT) cross-sectional images, in DICOM format, along with a 3D printing (additive manufacturing) setup. The in-house developed software InVesalius®️ is an open-source tool for medical imaging manipulation. The protocol describes image acquisition (CT scanning) procedures, and image post-processing procedures such as image segmentation, surface/volume rendering, mesh generation of a 3D digital model of the cranial defect and the desired prostheses, and their preparation for use in 3D printers. Furthermore, the protocol describes a detailed powder bed fusion additive manufacturing process, known as Selective Laser Sintering (SLS), using Polyamide (PA12) as feedstock to produce a 3-piece customized printed set per patient. Each set consists of a “cranial defect printout” and a “testing prosthesis” to assemble parts for precision testing, and a cranial “prostheses mold” in 2 parts to allow for the intraoperative modeling of the final implant cast using the medical grade Poly(methyl methacrylate) (PMMA) in a time span of a few min. The entire 3D processing time, including modelling, design, production, post-processing and qualification, takes approximately 42 h. Modeling the PMMA flap with a critical thickness of 4 mm by means of Finite Element Method (FEM) assures mechanical and impact properties to be slightly weaker than the bone tissue around it, a safety design to prevent fracturing the skull after a possible subsequent episode of head injury. On a parallel track, the Protocol seeks to provide guidance in the context of equipment, manufacturing cost and troubleshooting. Customized 3D PMMA prostheses offers a reduced operating time, good biocompatibility, and great functional and aesthetic outcomes. Additionally, it offers greater than 15-fold cost advantage over the usage of other materials, including metallic parts produced by additive manufacturing.

Many biomaterials are used for Bone Morphogenetic Proteins (BMPs) delivery in bone tissue engineering. The BMP carrier system&rsquo, s primary function is to hold these growth factors at the wound&rsquo, s site for a prolonged time and provide initial support for cells to attach and elaborate the extracellular matrix for bone regeneration. This study aimed to evaluate the nanostructured carbonated hydroxyapatite microspheres (nCHA) as an rhBMP-2 carrier on rats calvaria. A total of fifteen male Wistar rats were randomly divided into three groups (n = 5): clot (control group), rhBMP-2 associated with collagen membrane (COL/rhBMP-2) or associated with the microspheres (nCHA/rhBMP-2). After 45 days, the calvaria defect samples were evaluated through histological, histomorphometric, and SR-&micro, CT analyses to investigate new-formed bone and connective tissue volume densities. The descriptive histological analysis showed that nCHA/rhBMP-2 improved bone formation compared to other groups. These results were confirmed by histomorphometric and SR-&micro, CT analysis that showed substantially defect area filling with a higher percentage of newly formed (36.24 &plusmn, 6.68) bone than those with the COL/rhBMP-2 (0.42 &plusmn, 0.40) and Clot (3.84 &plusmn, 4.57) (p &lt, 0.05). The results showed that nCHA is an effective carrier for rhBMP-2 encouraging bone healing and an efficient alternative to collagen membrane for rhBMP-2 delivery.

The adaptation of trabecular bone microstructure to mechanical loads has been intensively investigated. However, loading-unrelated aspects of trabecular architecture remain unclear. We used synchrotron radiation-based X-ray microtomography to study the 3D microarchitecture of newly formed trabecular tissue in a defect produced in the cortical region of the rat tibia diaphysis, in the absence (7, 14, and 21 days) or the presence (21 days) of carbonated hydroxyapatite/alginate (cHA) microspheres. This work provides the first evidence that the woven bone trabecular network, formed during the healing process, displays a well-organized 3D microarchitecture consisting of nodes with 3 (3-N), 4 (4-N) and 5 (5-N) connecting trabeculae, with a mean relative abundance of (3-N)/(4-N)/(5-N) = 66/24/7, for the analyzed periods. The measured inter-trabecular angles (ITA) distribution presented a Gaussian profile, with mean value at 115° for 3-N nodes, and 105° for 4-N nodes, close to the angles of idealized 3D regular structures (120° and 109.5°, respectively). Changes in the dispersion of ITA distribution suggested that a highly symmetric trabecular fabric organized under tensegrity principles is formed early during the bone healing process. Post-implantation, cHA disaggregated into multiple fragments (~20–400 μm), stimulating osteoconduction and bone growth toward the interior of the medullary cavity. The presence of biomaterials in bone defects affected the trabecular dimensions; however, it did not interfere with the formation of geometrical motifs with topological parameters similar to those found in the sham-defects. Statement of Significance The trabecular bone microstructure enables the tissue to meet the necessary mechanical and functional demands. However, the process of trabecular microarchitecture formation during healing, in the absence or presence of a bone graft, is not yet well understood. This work demonstrated that, from the beginning of its formation in cortical bone defects, the woven-bone trabecular network is spatially organized according to the principle of tensegrity. This microarchitecture is comprised of highly symmetric geometric motifs and is an intrinsic characteristic of trabecular growth, regardless of hierarchical scale or mechanical stimulation. The addition of a biodegradable nanostructured calcium phosphate graft did not disrupt trabecular microarchitecture; however, graft biodegradation should be controlled to optimize the reproduction of intrinsic trabecular motifs throughout the defect.

The aim of this study was to fabricate and characterize dental composites containing hydroxyapatite nanoparticles (HApNPs). Four dental composites were produced from the same organic matrix (70 wt% Bis-GMA and 30 wt% TEGDMA), with partial replacement of BaBSi particles (65 wt%) by HApNPs in the following concentrations (wt%): E0 (0) – control, E10 (10), E20 (20) and E30 (30). Ca2+ and PO43− release was evaluated in solutions with different pHs (4, 5.5, and 7) using atomic emission spectroscopy with microwave-induced nitrogen plasma while the enamel remineralization potential was evaluated in caries-like enamel lesions induced by S. mutans biofilm using micro-CT. The following properties were characterized: degree of conversion (DC%), microhardness (KHN), flexural strength (FS), elastic modulus (EM) and translucency (TP). The higher the HApNPs content, the higher the Ca2+ and PO43− release. The ions release was influenced by pH (4 > 5.5 > 7) (p E10) (p

Made available in DSpace on 2020-12-12T02:02:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) The apoptosis-associated Speck-like protein containing a caspase-1 recruitment domain (ASC), present in inflammasomes, regulates inflammation events and is involved in osteogenic phenotype. Nevertheless, its function in bone repair induced by bone substitute biomaterials is unclear. This study aimed to unveil the role of ASC on osteoprogenitor and tissue response to stoichiometric-hydroxyapatite (HA), nanostructured carbonated-hydroxyapatite (CHA), and CHA containing 5% Strontium (SrCHA), characterized previously by XRD, uXRF-SR, and FTIR spectroscopy implants. Thereafter, conditioned media by the biomaterials were used later to treat pre-osteoblasts and an osteogenic stimulus was shown in response to the materials, with higher expression of Runx2, Osterix, ALP, and Collagen 1a1 genes, with significant involvement of inflammatory-related genes. Thus, to better address the involvement of inflammasome, primary cells obtained from both genotypes [Wild-Type (WT) and ASC Knockout (ASC-KO) mice] were subjected to conditioned media up to 7 days, and our data reinforces both HA and CHA induces lower levels of alkaline phosphatase (ALP) than SrCHA, considering both genotypes (p < 0.01), and ASC seems contribute with osteogenic stimulus promoted by SrCHA. Complimentarily, the biomaterials were implanted into both subcutaneous and bone defects in tibia. Histological analysis on 28 days after implantation of biomaterials into mice's subcutaneous tissue revealed moderate inflammatory response to them. Both histomorphometry and μCT analysis of tibias indicated that the biomaterials did not reverse the delay in bone repair of ASC KO, reinforcing the involvement of ASC on bone regeneration and bone de novo deposition. Also, the bone density in CHA was >2-fold higher in WT than ASC-KO samples. HA was virtually not resorbed throughout the experimental periods, in opposition to CHA in the WT group. CHA reduced to half-area after 28 days, and the bone deposition was higher in CHA for WT mice than HA. Taken together, our results show that biomaterials did not interfere with the healing pattern of the ASC KO, but CHA promoted higher bone deposition in the WT group, probably due to its greater biodegradability. These results reinforce the importance of ASC during bone de novo deposition and healing. Oral Surgery Department Universidade Veiga de Almeida Oral Surgery Department and Clinical Research Laboratory in Dentistry Universidade Federal Fluminense Oral Diagnosis Department Universidade Federal Fluminense Department of Applied Physics Centro Brasileiro de Pesquisas Físicas CBPF Department of Biotechnological and Applied Clinical Sciences University of L'Aquila UNESP – São Paulo State University Institute of Biosciences of Botucatu Department of Chemistry and Biochemistry Clinical Research Laboratory in Dentistry Universidade Federal Fluminense Directory of Life Sciences Applied Metrology Instituto Nacional de Metrologia Qualidade e Tecnologia (INMETRO) Oral Surgery Department Universidade Iguaçu UNESP – São Paulo State University Institute of Biosciences of Botucatu Department of Chemistry and Biochemistry CAPES: 001 FAPERJ: 2014/22689-3

X-ray photoelectron spectroscopy (XPS) is one of the main tools for hydroxyapatite (HA) surface characterization in developing materials for biomedical and heterogeneous catalysis. Despite the XPS technique's potential to correlate binding energies with existing photo-emitter sites on near-surfaces, few previous studies analyzed this aspect for HA and metal-substituted HA surfaces. In this work, we theoretically reconstructed the XPS spectra of stoichiometric HA and lead-substituted hydroxyapatite (PbCaHA, Ca10-xPbx(PO4)6(OH)2; x = 2, 10) using a first-principles linear combination of atomic orbitals embedded cluster approach and periodic supercell band structures within the framework of Density Functional Theory (DFT). We take into account photoemission lines contributions from Ca(1), Ca(2), Pb(1) and Pb(2) sites located on surface and near-surface depths (up to ∼15 A) along the (0 0 1) and (1 0 0) surfaces. The calculated DFT spectra of HA and PbCaHA were compared with high-resolution XPS spectra previously characterized by synchrotron X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS). A combined theoretical and experimental approach enables decoding of the complex structure of HA and PbCaHA in XPS spectra. It was found that XPS binding energies profiles depend significantly on photo-emitters from near-surface sites and surface crystallographic orientation. The main Ca 2p3/2 envelope peak in HA is predominantly from Ca(1) and Ca(2) sites (∼347.4 eV), while the weaker peak is due to the Ca(2) site only (∼345.0 eV). Variations on HA nanoparticle morphology could be a critical factor for changes in XPS binding energies' profile.

Some biomaterials can be used to promote tissue repair process. The biological substitutes (biomaterials such as hydroxyapatite beads) can be used with some advantages and purpose of mimicking responses to on-site repair of the injured bone. The objective of this study was to evaluate the osteogenic potential of the biomaterial composed of hydroxyapatite and alginate in place of the critical defect. bioceramic samples stoichiometric hydroxyapatite was produced by the precipitation method, wet method with ion molar ratio of Ca 10 (PO 4) 6 (OH) 2, in which the Ca / P ratio was equal to 1.67. The reaction conditions were favorable to the composition of a biomaterial with crystalline phase. The synthesis of the biomaterial composed of hydroxyapatite and alginate microspheres (HAAlg5%; 200 ø 425mm) was obtained from two primary solutions with the aim of, in optimal reactive conditions, to form the precipitate. After synthesis the microspheres were implanted into the defect site. The potential effects of using HAAlg5% and the application of vibratory waves in the critical defect repair were unknown and the results described in this study are promising, considering the systemic therapy and at the site of injury. The biomaterial used promoted repair the injured tissue.

The role of apoptosis-associated speck-like protein containing a caspase-1 recruitment domain (ASC) in bone healing remains to be understood. To address this issue, we investigated the requirement of inflammasome-related genes in response to bone morphogenetic protein 7 (BMP7)-induced osteoblast differentiation in vitro. To validate the importance of ASC on osteogenesis, we subjected wild-type (WT) and ASC knockout C57BL/6 mice (ASC KO) to tibia defect to evaluate the bone healing process (up to 28 days). Our in vitro data showed that there is an involvement of ASC during BMP7-induced osteoblast differentiation, concomitant to osteogenic biomarker expression. Indeed, primary osteogenic cells from ASC KO presented a lower osteogenic profile than those obtained from WT mice. To validate this hypothesis, we evaluated the bone healing process of tibia defects on both WT and ASC KO mice genotypes and the ASC KO mice were not able to fully heal tibia defects up to 28 days, whereas WT tibia defects presented a higher bone de novo volume at this stage, evidencing ASC as an important molecule during osteogenic phenotype. In addition, we have shown a higher involvement of runt-related transcription factor 2 in WT sections during bone repair, as well as circulating bone alkaline phosphatase isoform when both were compared with ASC KO mice behavior. Altogether, our results showed for the first time the involvement of inflammasome during osteoblast differentiation and osteogenesis, which opens new avenues to understand the pathways involved in bone healing.

The combination of calcium phosphate with blood-derived growth factors (BDGF) has been widely used in bone regeneration procedures although its benefits are still unclear. The purpose of this study was to evaluate whether or not BDGF improves the efficacy of a modified carbonated calcium phosphate biomaterial in sinus floor augmentation. Ten patients underwent 20 sinus floor augmentation procedures using nanostructured carbonated hydroxyapatite (cHA) microspheres alone or associated with BDGF in a randomized controlled clinical trial. The in vitro release of growth factors was assessed by an elution assay. Bone grafts were randomly implanted in the right and left maxillary sinuses of each participant, associated either with a 0.9% saline solution or BDGF. Bone gain was evaluated through cone beam tomography after 180 days. Nine women and one man composed the sample. The blood-derived concentrates were able to release high levels of growth factors and cytokines. A significant clinical advantage was observed in the use of the BDGF after fibrin polymerization around the biomaterial microspheres, optimizing the surgical procedures, thereby reducing the time and displacement, and improving the adaptation of the biomaterial in the maxillary sinus. No synergistic effect was observed in bone formation when cHA was associated with BDGF (p > 0.05). Equivalent new bone formation was observed for cHA in the presence or absence of the BDGF concentrate in bilateral sinus floor elevation after 6 months. Blood-derived growth factors did not improve bone repair when associated with calcium phosphate in sinus lift procedures.

Os biomateriais nanoestruturados têm se destacado como elementosestratégicos para a medicina regenerativa devido à sua grande áreaespecífica, a sua característica de atuar como veículo portador e liberadorde fatores de crescimento, células e pela sua mobilidade no plasma,no meio extra e intra-celular. Nos últimos anos, a equipe executora desteestudo, constituída por pesquisadores do CBPF, UFF, UFRJ e INMETROtêm concentrado seus esforços no desenvolvimento de novos fosfatos decálcio na forma nanoestruturada e com substituições iônicas para uso clínico.Estas características potencializam a bioabsorção do material e suaeficiência na regeneração tecidual, bem como seu uso como nanocarreadorde biomoléculas (proteínas, peptídeos, fatores de crescimento e fármacos).Neste estudo foi produzido e avaliado clinicamente um novo biomaterialpara a regeneração óssea, seguindo o princípio de “quality by desing”,visando aumentar sua eficiência em procedimentos clínicos específicostais como o tratamento do edentulismo. Considerando o enxerto autógenocomo referência, foram realizadas mudanças profundas no desenhodos enxertos de fosfato de cálcio convencionais no sentido de processaro biomaterial na forma de uma matriz microporos não cerâmica constituídapor compósito nanoestruturado de hidroxiapatita carbonatada e obiopolímero alginato de sódio – associado ao concentrado de fatores decrescimento. Este projeto objetivou avaliar clinicamente o ganho ósseo naelevação da membrana sinusal após implantação de microesferas de hidroxiapatitacarbonatada nanoestruturada associadas ao concentrado defatores de crescimento em fase líquida, obtido do sangue periférico autógeno.O levantamento do assoalho do seio maxilar utilizando microesferasde hidroxiapatita carbonatada nanoestruturada asssociada ou não aosfatores de crescimento não identificou o efeito sinérgico no aumento dotecido ósseo quando o biomaterial era associado aos fatores de crescimentona fase líquida. Foi observada uma formação óssea equivalente em ambosos lados operados após seis meses do procedimento de elevação sinusal.Com este estudo concluímos que as microesfears de hidroxiapatita carbonatadananoestruturada é segura e eficaz para uso humano e pode seruma alternativa segura para uso na Rede SUS em procedimentos de regeneração óssea com custo muito inferior ao biomaterial sintético disponívelno Mercado nacional. Estudos futuros multicêntricos com um númeromaior de participantes devem ser realizados (Fase 3 da Pesquisa Clínica).

Calcium phosphate (CP) has been used as biomaterial to regenerate bone defects. In order to improve its biological properties, substitutions in the calcium phosphate chemical structure have been investigated. Zinc has stimulatory effects on in vitro and in vivo bone formation and an inhibitory effect on in vitro osteoclastic bone resorption. The aim of this systematic review (SR) was to assess the effect of zinc incorporation into calcium phosphate on bone repair. This SR was performed in accordance with the PRISMA guidelines and Preclinical Systematic Review & Meta-analysis Facility. An electronic search was conducted using the MEDLINE/PubMed, Cochrane, Scopus, and Scielo databases. Eligibility criteria included only animal studies that compared the effect of zinc incorporation into CP–based materials on bone repair. The selection process yielded 18 studies among 335 retrieved. The ARRIVE guidelines checklist was used to assess the articles’ quality. It was observed that zinc incorporation into CP did not affect its biocompatibility, tends to reduce the resorption rate and was considered to be osteoconductive. Most of the manuscripts suggested that zinc incorporation can enhance bone repair. The results indicate that zinc-doped CP has potential for increasing bone repair, being an interesting option for bone regeneration biomaterial.

The non-equilibrium electro-thermodynamic properties of magnetized plasma produced by a modified radio-frequency magnetron sputtering system were investigated in detail. The plasma was analyzed using Hall, Langmuir, and Faraday probes and optical emission spectroscopy, and numerical simulations were conducted to determine the electric and magnetic field profiles. It is found that the occurrence of lower hybrid resonance and excitation of helicon waves are satisfied locally along the plasma profile (Z). This unusual effect in magnetron sputtering systems plays an important role in the increase of the electrons and ions temperature improving the quality of the films produced. Films of complex structure as hydroxyapatite that have biomedical applications were produced along the Z to confirm our plasma results. The films were characterized by performing grazing incidence X-ray diffraction using synchrotron radiation, X-ray photoelectron spectroscopy and atomic force microscopy. The microstructure analysis of hydroxyapatite films produced at different Z revealed that films with high crystallinities and with ideal stoichiometries (Ca/P = 1.67 ± 0.05) were produced within a magnetic cusp region (26 mm

Internalization of hydroxyapatite nanoparticles in SAOS-2 osteoblasts for 2 and 24 h was investigated in vitro using 5 and 50 µg/mL nanoparticles in culture medium. No cytotoxic effects were observed in a PrestoBlue viability assay. Focused ion beam-scanning electron microscopy and transmission electron microscopy were used to study nanoparticle trafficking inside cells and to characterize the physicochemical properties of the remodeled nanoparticles. Nanoparticles were actively internalized by cells and maintained in intracellular membrane-bound compartments. Dissolution of hydroxyapatite nanoparticles was observed inside phagolysosome in all samples. After 24 h of internalization in cell culture assays, reprecipitation of calcium phosphate minerals was observed in membrane-bound compartments in 5 and 50 µg/mL samples. Compared to the original nanoparticles, the reprecipitated calcium phosphate phase presented a different morphology, structure, and chemical composition. Two sample preparation methods were used and confirmed that reprecipitation of the calcium phosphate crystallites occurred in the intracellular environment and not during electron microscopy sample preparation. Reprecipitation of calcium phosphate prevented the release of large amounts of calcium and phosphate ions inside the cells. This phenomenon may be linked to physiological processes in the cell that control the concentration and trafficking of intracellular calcium ions, which are highly controlled by cells. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 428-439, 2018.

Insulin-loaded calcium phosphate nanoparticles have been proposed as a potential drug delivery system for the oral treatment of diabetes and to stimulate bone cell proliferation and bone mineralization. The kinetics of insulin incorporation onto hydroxyapatite (HA) and Sr (SrHA)- and Zn (ZnHA)-substituted hydroxyapatite nanoparticles was investigated using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, zeta potential measurements and circular dichroism (CD) spectroscopy. The increase in insulin concentration on HA, SrHA and ZnHA was a typical physical adsorption process controlled by electrostatic forces and followed a Freundlich isotherm model. Zn substitution enhanced the capacity of the apatite surface to adsorb insulin, whereas Sr substitution inhibited insulin uptake. The surface stoichiometry and mesopore specific area induced by Zn and Sr substitution are proposed as the main causes of the difference in insulin adsorption. Despite the weak interaction between insulin and the apatite surface, the CD spectra revealed a decrease in the insulin ellipticity when the protein was adsorbed on the HA, SrHA and ZnHA nanoparticles. A reduction in alpha-helical structures and an increase in beta sheets were observed when insulin interacted with the HA surface. A less pronounced effect was found for ZnHA, for which a subtle decrease in alpha-helical structures was followed by an increase in turn structures. Interaction with the SrHA surface did not change the native insulin conformation. In vitro cell culture experiments lasting 24h using F-OST stromal cells showed that the insulin loaded on HA and ZnHA did not affect cell proliferation but the insulin loaded on SrHA improved cell proliferation. These results suggest that the stability of the native protein conformation is an important factor to consider when cells interact with insulin adsorbed on metal-substituted HA surfaces.

Background: The use of nanobiomaterials is increasing each day. Among the immense variety of nanomaterials developed and studied the hydroxyapatite is one of the most ones. Objective: In this study we developed and tested nano-hydroxyapatite dopped with Ho-166 for bone cancer. Results: The results showed that the nano-hydroxyapatite dopped with Ho-166 has a great affinity for the bone. Conclusion: The pre-clinical studies support the use as a nano-radiopharmaceuticals for bone cancer treatment and diagnosis.

A cidade de Santo Amaro da Purificacao (BA) foi contaminada por mais de 30 anos com escorias de uma fundicao de Pb. O objetivo deste estudo foi o de avaliar o grau de contaminacao por chumbo em solos coletados proximos a metalurgica, assim como avaliar a toxicidade proporcionada por chumbo nestes solos e identificar a distribuicao geoquimica do Pb nestes solos antes e apos o tratamento com diferentes fontes de fosforo. Os solos foram remediados com a aplicacao de KH2PO4 e rocha fosfatada. Apos 120 dias de experimento, os resultados confirmam a eficacia do sal KH2PO4 como atenuante da ecotoxicidade do Pb e a migracao deste metal de fracoes labeis para fracoes geoquimicas mais recalcitrantes do solo.

Mônica Diuana Calasans-Maia,1 Carlos Alberto Brazil Barboza Junior,2 Carlos Alberto Soriano-Souza,3 Adriana Terezinha Neves Novellino Alves,4 Marcelo Jose de Pinheiro Uzeda,1 Victor R Martinez-Zelaya,3 Elena Mavropoulos,3 Maria Helena Rocha Leão,5 Ronaldo Barcellos de Santana,2 Jose Mauro Granjeiro,1 Alexandre Malta Rossi31Clinical Research in Dentistry Laboratory, School of Dentistry, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil; 2Department of Periodontology, School of Dentistry, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil; 3Department of Condensed Matter, Applied Physics and Nanoscience, Brazilian Center for Research in Physics, Rio de Janeiro, Brazil; 4Department of Stomatology. School of Dentistry, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil; 5Department of Biochemical Engineering, School of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, BrazilBackground and objective: Tetracycline and its derivatives, combined with calcium phosphates, have been proposed as a delivery system to control inflammatory processes and chronic infections. The objective of this study was to evaluate the microspheres of alginate encapsulated minocycline-loaded nanocrystalline carbonated hydroxyapatite (CHAMINO) as a biomimetic device to carry out target-controlled drug delivery for alveolar bone repair.Methods: CHAMINO microspheres were implanted in a rat central incisor socket after 7 and 42 days. New bone was formed in both groups between 7 and 42 days of implantation. However, the bone growth was significantly higher for the CHAMINO microspheres.Results: The minocycline (MINO) loading capacity of the nanocrystaline carbonated hydroxyapatite (CHA) nanoparticles was 25.1±2.2 μg MINO/mg CHA for adsorption over 24 hrs. The alginate microspheres containing minocycline-loaded CHA were biologically active and inhibited the Enterococcus faecalis culture growth for up to seven days of the MINO release. An osteoblastic cell viability assay based on the resazurin reduction was conducted after the cells were exposed to the CHAMINO powder and CHAMINO microspheres. Thus, it was found that the alginate extracts encapsulated the minocycline-loaded CHA microspheres and did not affect the osteoblastic cell viability, while the minocycline-doped CHA powder reduced the cell viability by 90%.Conclusion: This study concluded that the alginate microspheres encapsulating the minocycline-loaded nanocrystalline carbonated hydroxyapatite exhibited combined antibacterial activity against Enterococcus faecalis with cytocompatibility and osteoconduction properties. The significant improvement in the new bone formation after 42 days of implantation suggests that the CHAMINO microsphere has potential in clinical applications of bone regeneration.Keywords: nanomaterials, carbonated hydroxyapatite, minocycline, biocompatibility, bone regeneration

Drug delivery technology is a promising way to enhance the therapeutic efficacy of drugs. The purpose of this study is to evaluate the physical and chemical properties of hydroxyapatite ceramic microspheres loaded with doxycycline (HADOX), their effects on in vitro osteoblast viability, and their antimicrobial activity, and to determine the effects of DOX on the healing of rat sockets after tooth extraction. The internal microsphere porosity was sensitive to the treatment used to adsorb DOX onto microsphere surface; HA microspheres without DOX presented 26% of pores, whereas HADOX0.15 microspheres presented 52.0%. An initial drug release of 49.15 μg/ml was observed in the first 24 hr. The minimal inhibitory concentration (MIC) tested against Enterococcus faecalis demonstrated that bacterial growth was inhibited for up to 7 days. Results of cell viability and cell proliferation did not indicate statistical differences in the metabolic activity of HADOX samples relative to HA without DOX microspheres (p > .05). After 1 week, a discreet inflammation reaction was observed in the control group, and after 6 weeks, newly-formed bone was observed in the HADOX0.15 (p < .05). The HADOX did not interfere in the bone repair and controlled the early inflammatory response. HADOX could be a promising biomaterial to promote bone repair in infected sites.

Purpose: To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair. Methods: Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldner’s trichrome. Results: The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect. Conclusion: The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.

Hydroxyapatite (HA) is the main constituent of bone mineral in vertebrates and is widely used as a biomaterial in biomedical studies and medical clinics. The synthesis of this calcium phosphate phase is a crucial factor in its potential use in various applications as well as in understanding the nucleation and growth processes in biological mineralization (biomineralization). In this work, a sequential analysis of the different steps of HA synthesis in aqueous media was performed by using cryo-transmission electron microscopy (Cryo-TEM), which allows preservation of the specimens at different stages of the synthesis process, preventing their modification during drying. X-ray energy dispersive spectroscopy and electron diffraction, in addition to high-resolution imaging, were performed on vitrified samples. We showed that drying a specimen from the synthesis solution induces the crystallization of nanoparticles into an HA phase after 30 min of reaction, while when analyzed by Cryo-TEM, crystalline nanoparticles were detected only after 15 h. Calcium phosphate nanoparticles presented three different morphologies: irregular shapes characterized by low contrast in TEM (5 min), isotropic shapes with well-defined contrast (10 min) and needle-like shapes (after 30 min). The long axis of the HA needle-like nanoparticles can be associated with the c-axis direction of the hexagonal unit cell, which can thus be assigned to the preferential crystallization direction. However, a diffraction signal of the nanoparticles in vitreous ice that “mimics” the original solution was detected by Cryo-TEM only after 15 h of synthesis. These apparently controversial results are discussed in this manuscript considering various aspects of the use of Cryo-TEM in relation to the current concepts of calcium phosphate nucleation and growth.

Victor R Martinez-Zelaya,1 Laila Zarranz,2 Edher Z Herrera,1 Adriana T Alves,2 Marcelo José Uzeda,2 Elena Mavropoulos,1 André L Rossi,1 Alexandre Mello,1 José M Granjeiro,2,3 Monica D Calasans-Maia,2 Alexandre M Rossi11Department of Condensed Matter, Applied Physics and Nanoscience, Brazilian Center for Research in Physics, Rio de Janeiro, RJ, Brazil; 2Dental Clinical Research Center, Oral Diagnosis Department and Oral Surgery Department, Dentistry School, Fluminense Federal University, Niteroi, RJ, Brazil; 3National Institute of Metrology, Quality and Technology, Duque de Caxias, RJ, BrazilBackground: Zinc-doped hydroxyapatite has been proposed as a graft biomaterial for bone regeneration. However, the effect of zinc on osteoconductivity is still controversial, since the release and resorption of calcium, phosphorus, and zinc in graft-implanted defects have rarely been studied.Methods: Microspheres containing alginate and either non-doped carbonated hydroxyapatite (cHA) or nanocrystalline 3.2wt% zinc-doped cHA (Zn-cHA) were implanted in critical-sized calvarial defects in Wistar rats for 1, 3, and 6months. Histological and histomorphometric analyses were performed to evaluate the volume density of newly formed bone, residual biomaterial, and connective tissue formation. Biomaterial degradation was characterized by transmission electron microscopy (TEM) and synchrotron radiation-based X-ray microfluorescence (SR-μXRF), which enabled the elemental mapping of calcium, phosphorus, and zinc on the microsphere-implanted defects at 6months post-implantation.Results: The bone repair was limited to regions close to the preexistent bone, whereas connective tissue occupied the major part of the defect. Moreover, no significant difference in the amount of new bone formed was found between the two microsphere groups. TEM analysis revealed the degradation of the outer microsphere surface with detachment of the nanoparticle aggregates. According to SR-μXRF, both types of microspheres released high amounts of calcium, phosphorus, and zinc, distributed throughout the defective region. The cHA microsphere surface strongly adsorbed the zinc from organic constituents of the biological fluid, and phosphorus was resorbed more quickly than calcium. In the Zn-cHA group, zinc and calcium had similar release profiles, indicating a stoichiometric dissolution of these elements and non-preferential zinc resorption.Conclusions: The nanometric size of cHA and Zn-cHA was a decisive factor in accelerating the in vivo availability of calcium and zinc. The high calcium and zinc accumulation in the defect, which was not cleared by the biological medium, played a critical role in inhibiting osteoconduction and thus impairing bone repair.Keywords: zinc-doped carbonated hydroxyapatite, nanocomposite, synchrotron radiation-based X-ray microfluorescence, zinc/calcium bioavailability, bone regeneration

RESUMO Este trabalho investigou o processo de hidrólise química de poli(tereftalato de etileno) (PET) em meio alcalino; especificamente de garrafas incolores e coloridas pós-uso. A reciclagem química de embalagens PET pós-uso ainda é muito pouco explorada no Brasil, não sendo tão diferente do que está sendo praticado em outros países. Dentre variáveis possíveis de investigação, aquelas estudadas neste trabalho foram a concentração de hidróxido de sódio (NaOH) e a cor do PET. A reação de despolimerização do PET pós-uso foi realizada na concentração de 1,0, 3,0, 5,0, 7,5 e 10,0 mol L-1 de NaOH, sendo que em 7,5 mol L-1 foi aquela que mostrou os melhores resultados, relativamente à extensão da reação e à pureza do monômero recuperado, o ácido tereftálico (TPA). A reação também foi feita para PET de cores diferentes, na concentração de 7,5 mol L-1 de NaOH, cujos resultados mostraram um menor desempenho quando comparados com aqueles obtidos para o PET não colorido. Esse resultado sugere ser devido à presença de corantes, que pela estrutura química dos mesmos, competem pelo ataque nucleofílico do íon hidroxila (OH-), durante a reação de hidrólise do PET. As análises por Espectrofotometria no Infravermelho (FTIR), Difração de Raios X (DRX) e Termogravimétrica (TGA/DTG) confirmaram que os produtos de reação resultaram em TPA, uma vez que os espectros foram coincidentes com aqueles do TPA comercial. O crescente consumo de embalagens PET e o descarte ambiental aleatório precisam de soluções rápidas; os resultados do presente trabalho são importantes e corroboram com o avanço da pesquisa para a reutilização de matéria prima. ABSTRACT This work investigated the chemical hydrolysis process of polyethylene terephthalate (PET) in alkaline medium; specifically, colorless and colored post-consume bottles. The chemical recycling of post-consume PET bottles is still very little explored in Brazil, not being so different from what is being practiced in other countries. Among possible variables of investigation, in this work was studied the sodium hydroxide (NaOH) concentration and the PET color. The post-consume PETdepolymerization reaction was performed at the concentrations of 1.0, 3.0, 5.0, 7.5 and 10.0 mol L-1 NaOH, and in 7.5 mol L-1was the one that showed the best results, regarding the extent of the reaction and the purity of the recovered monomer, terephthalic acid (TPA). The reaction was also made for PET of different colors at the concentration of 7.5 mol L-1 NaOH, whose results showed a lower performance when compared to those obtained for non-colored PET. This result suggests that it is due to the presence of dyes, which, due to their same chemical structure, compete for nucleophilic attack of the hydroxyl ion (OH-) during the hydrolysis reactionof of PET. Infrared Spectrophotometry (FTIR), X-ray diffraction (XRD), as well as Thermogravimetric (TGA / DTG) analysis confirmed that the reaction products resulted in TPA, since the spectra were coincident with those of the commercial TPA. The increasing consumption of PET packaging and aleatory environmental disposal need quick solutions; the results of this work are important and corroborate with the advance of the research for reutilization of raw material.

Background Bone tissue is capable of self-healing in the event of injuries. However, situations such as the patient‘s age or size of the damage can compromise natural healing, bringing to the fore the need for interventions to treat bone injuries. Tissue engineering presents treatment alternatives involving the use of cells and associated biomaterials. In this context, studies using biomaterials claim that carbonated hydroxyapatite (CHA) is more resorbable than hydroxyapatite (HA) and has biological similarity to bone hydroxyapatite. Methods Parameters of indirect contact (cytotoxicity, proliferation, and migration) of the extract obtained from spheres of carbonated hydroxyapatite associated with murine bone marrow stem cells (BMSCs) in vitro were evaluated. Then the osteogenic potential of CHA extract in murine BMSCs in vitro was assessed by quantification of calcium matrix, alkaline phosphatase levels and gene expression Col1A1 and Bglap. Non-critical size bone defects were performed in rat femur. After 14 days of healing, bone blocks were obtained for analysis from treated animals and compared to non-treated animals by histological and histomorphometric evaluation. Results The CHA extract showed osteoinductive properties in vitro without the need to add osteogenic inducing medium. The ability to induce osteogenic differentiation in undifferentiated cells was confirmed by increased activity of alkaline phosphatase, formation of mineralized nodules and increased expression of the Col1A1 and Bglap genes after 7 and 14 days of differentiation. All groups presented bone neoformation at the injury site 14 days after the operation. Histomorphometric analysis showed no statistical difference between groups in the parameters of bone formation, biomaterial and connective tissue. Conclusion The CHA spheres have in vitro osteoinductive properties and, when loaded with murine BMSCs, have the potential for bone repair and regeneration in vivo, presenting biocompatibility and osteoconductive, making it a promising alternative for bone tissue engineering applications.

The knowledge on human tissue is very important to recognize desirable properties of biomaterials. Host cells, extracellular matrix, integrated vessels and interstitial fluids create a complex and dynamic system able to regenerate and respond to environmental stimuli. Myoglobin is a protein with most of α-helices on its secondary structure, and responsible for oxygen binding and release in muscles, by the heme group. This work investigates the Mb adsorption process onto zinc-hydroxyapatite (ZnHA) surface by spectroscopic studies. To do so, ZnHA (0.05 g) was incubated with 4mL of 2mg Mb/mL on phosphate buffer solution pH 6.0 for 24h at 37°C. The FTIR analyses of ZnHA powders before and after protein adsorption provided information concerning the protein content. UV-Vis spectrocopy in the reflectance mode suggested a mixture of MbO2 and Met Mb on lyophilized solid Mb, and the prevalence of MetMb form when Mb was adsorbed on ZnHA sample. The decrease of UV-Vis secondary bands suggests interactions through the Mb heme group and the ZnHA surfaces. Circular Dichroism (CD) spectroscopy indicated the maintenance of the Mb α-helices secondary structure after the adsorption process on ZnHA powders.

The hydroxyapatite (HA) is a biocompatible and bioactive biomaterial used as bone substitute, however, the high crystallinity of HA and consequently its low solubility may be a limitation for its clinical use. In order to improve the biosorption of HA, the partial substitutions in the chemical structure and doping with small amounts of impurities have been study. The objective of this study was to evaluate the biocompatibility of 3% Zinc-containing nanostructured carbonated hydroxyapatite (ZncHA) compared with the carbonated hydroxyapatite (cHA), both synthesized at 37°C and non-sintered, using as control the stoichiometric HA microspheres in subcutaneous of mice. The X-ray Diffraction (XRD) and Vibrational Spectroscopy in Infra Red Fourier Transform (FTIR) were used to characterize the biomaterials. In vivo test was performed in BALB/c mice by implanting of HA, cHA and ZncHA spheres in the subcutaneous tissue for 1, and 9 weeks (n=5). The negative control consisted in incision without material implantation (Sham group). The samples were histological processed to descriptive analysis of biological effect. The microscopic analysis showed a similar granulation reaction between groups at the first experimental period. In 9 weeks there was a time dependent biosorption of cHA compared with other groups. In conclusion, the biomaterials tested were biocompatible and cHA group showed a significant biosorption in comparison with HA and ZncHA groups. The doping of zinc did not influence the biocompatibility of biomaterial, however, change the biosorption response

The hydroxyapatite (HA) is a biocompatible and bioactive biomaterial used as bone substitute, however, the high crystallinity of HA and consequently its low solubility may be a limitation for its clinical use. In order to improve the biosorption of HA, the partial substitutions in the chemical structure and doping with small amounts of impurities have been study. The objective of this study was to evaluate the biocompatibility of 3% Zinc-containing nanostructured carbonated hydroxyapatite (ZncHA) compared with the carbonated hydroxyapatite (cHA), both synthesized at 37°C and non-sintered, using as control the stoichiometric HA microspheres in subcutaneous of mice. The X-ray Diffraction (XRD) and Vibrational Spectroscopy in Infra Red Fourier Transform (FTIR) were used to characterize the biomaterials. In vivo test was performed in BALB/c mice by implanting of HA, cHA and ZncHA spheres in the subcutaneous tissue for 1, and 9 weeks (n=5). The negative control consisted in incision without material implantation (Sham group). The samples were histological processed to descriptive analysis of biological effect. The microscopic analysis showed a similar granulation reaction between groups at the first experimental period. In 9 weeks there was a time dependent biosorption of cHA compared with other groups. In conclusion, the biomaterials tested were biocompatible and cHA group showed a significant biosorption in comparison with HA and ZncHA groups. The doping of zinc did not influence the biocompatibility of biomaterial, however, change the biosorption response

Nanostructured carbonated hydroxyapatite (nCHA) is a promising biomaterial for bone tissue engineering due to its chemical properties, similar to those of the bone mineral phase and its enhanced in vivo bioresorption. However, the biological effects of nCHA nanoparticles on cells and tissues are not sufficiently known. This study assessed the impact of exposing pre-osteoblasts to suspensions with high doses of nCHA nanoparticles with high or low crystallinity. MC3T3-E1 pre-osteoblasts were cultured for 1 or 7 days in a culture medium previously exposed to CHA nanoparticles for 1 day. Control groups were produced by centrifugation for removal of bigger nCHA aggregates before exposure. Interaction of nanoparticles with the culture medium drastically changed medium composition, promoting Ca, P, and protein adsorption. Transmission Electron microscopy revealed that exposed cells were able to internalize both materials, which seemed concentrated inside endosomes. No cytotoxicity was observed for both materials, regardless of centrifugation, and the exposure did not induce alterations in the release of pro-and anti-inflammatory cytokines. Morphological analysis revealed strong interactions of nCHA aggregates with cell surfaces, however without marked alterations in morphological features and cytoskeleton ultrastructure. The overall in vitro biocompatibility of nCHA materials, regardless of physicochemical characteristics such as crystallinity, encourages further studies on their clinical applications.