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During bone tissue regeneration, neovascularization is critical, and the formation of a blood supply network is crucial for bone growth stimulation and remodeling. Previous studies suggest that bioelectric signals facilitate the process of angiogenesis. Owing to their biomimetic electroactivity, piezoelectric membranes have garnered substantial interest in the field of guided bone regeneration. Nevertheless, the knowledge of their influence due to varying surface potentials on the progression of angiogenesis remains ambiguous. Therefore, we proposed the preparation of an electroactive material, P(VDF-TrFE), and investigated its effects on the activity and angiogenic functions of human umbilical vein endothelial cells (HUVECs). The HUVECs were directly cultured on P(VDF-TrFE) membranes with different surface potentials. Subsequently, cell viability, proliferation, migration, tube formation, and expressions of related factors were assessed through appropriate assays. Our results revealed that the negative surface potential groups exerted differential effects on the modulation of angiogenesis in vitro. The P(VDF-TrFE) membranes with negative surface potential exhibited the greatest effect on cellular behaviors, including proliferation, migration, tube formation, and promotion of angiogenesis by releasing key factors such as VEGF-A and CD31. Overall, these results indicated that the surface potential of piezoelectric P(VDF-TrFE) membranes could exert differential effects on angiogenesis in vitro. We present a novel approach for designing bioactive materials for guided bone regeneration.

Background Improvements in the early osseointegration of titanium implants require investigations on the bone-implant interface, which is a critical and complex challenge. The surface cleanliness of titanium implants plays an important role at this interface. However, the implant surface would inevitably absorb contamination such as organic hydrocarbons, which is not conductive to the establishment of early osseointegration. Herein, an optimized approach for removing contamination from titanium surfaces was studied. Methods The TiO2-B＠anatase NWs (nanowires) were prepared on titanium substrates through a hydrothermal process. A methylene blue degradation experiment was performed to assess the photodegradation activity. The cleaning effect of the photocatalysis of TiO2-B＠anatase NWs on a titanium surface and the cellular early response was determined by analyzing cell morphology, attachment, proliferation and differentiation. Results The results indicated that the photocatalysis of TiO2-B＠anatase NWs could effectively remove hydrocarbons on titanium surfaces without sacrificing the favourable titanium surface morphology. The methylene blue degradation experiment revealed that the photocatalysis of TiO2-B＠anatase NWs had powerful degradation activity, which is attributed to the presence of strong oxidants such as ·OH. In addition, compared to the merely ultraviolet-treated titanium surfaces, the titanium surfaces treated after the NWs photocatalytic cleaning process markedly enhanced cellular early response. Conclusion The photocatalysis of TiO2-B＠anatase NWs for the removal of contamination from titanium surfaces has the potential to enable the rapid and complete establishment of early osseointegration.

The effect of changes in surface charge on the biological properties of implants is not clear. The objective of this study was to evaluate the biological properties of the surface of titanium sheets with different charges due to different treatment methods. Titanium sheets were sandblasted with large grit and underwent acid etching before being subsequently divided into the following groups: SLA, no further treatment; SLA-Ca2+, immersed in 1% CaCl2 solution; SLA-NaCl, immersed in saline; and SLA-Ca2+-NaCl, immersed in 1% CaCl2 solution followed by saline. Surface characteristics were evaluated using field-emission scanning electron microscopy with energy-dispersive spectrometry, surface profilometry, and contact angle assays. Additionally, we used a ζ-potential analyzer to directly measure the electrostatic charge on the different group surfaces. The effect of changes in the Ti surface on biological processes after different treatments was determined by analyzing fibronectin adsorption, osteoblast-like MG63 cell adhesion and proliferation, and the expression of osteogenesis-related genes. Compared to the SLA surface, the other three groups contained corresponding trace elements because they were soaked in different liquids; the contact angles of the three groups were not significantly different, but they were significantly smaller than that of the SLA group; and there was no change in the surface topography or roughness. Furthermore, the SLA-Ca2+ group had a significantly reduced negative charge compared to that of the other three groups. There were no differences between the SLA-NaCl and SLA-Ca2+-NaCl groups in terms of negative charge, and the SLA group surface carried the most negative charge. Fibronectin adsorption capacity and cytological performance testing further showed that the SLA-Ca2+ group had the most significant change, followed by the SLA-NaCl and SLA-Ca2+-NaCl groups; the SLA group had significantly lower capacity and performance than the other three groups. These results suggest that the surface charge of the titanium sheet changed when immersed in different liquids and that this treatment enhanced biocompatibility by reducing the electrostatic repulsion between biomaterials and biomolecules.

Background Improvements in the early osseointegration of titanium implants require investigations on the bone-implant interface, which is a critical and complex challenge. The surface cleanliness of titanium implants plays an important role at this interface. However, the implant surface would inevitably absorb contamination such as organic hydrocarbons, which is not conductive to the establishment of early osseointegration. Herein, an optimized approach for removing contamination from titanium surfaces was studied. Methods The TiO2-B＠anatase NWs (nanowires) were prepared on titanium substrates through a hydrothermal process. A methylene blue degradation experiment was performed to assess the photodegradation activity. The cleaning effect of the photocatalysis of TiO2-B＠anatase NWs on a titanium surface and the cellular early response was determined by analyzing cell morphology, attachment, proliferation and differentiation. Results The results indicated that the photocatalysis of TiO2-B＠anatase NWs could effectively remove hydrocarbons on titanium surfaces without sacrificing the favourable titanium surface morphology. The methylene blue degradation experiment revealed that the photocatalysis of TiO2-B＠anatase NWs had powerful degradation activity, which is attributed to the presence of strong oxidants such as ·OH. In addition, compared to the merely ultraviolet-treated titanium surfaces, the titanium surfaces treated after the NWs photocatalytic cleaning process markedly enhanced cellular early response. Conclusion The photocatalysis of TiO2-B＠anatase NWs for the removal of contamination from titanium surfaces has the potential to enable the rapid and complete establishment of early osseointegration.

Understanding of the complicated interactions between biomaterials and cells can accelerate biomedical developments. Recently, many in vitro studies have emphasized the biological features of nanowires (NWs) on the cell’s early response. A type of unique clustered anatase/rutile NWs (ARNWs) was generated using a simple hydrothermal reaction on titanium in the present study. The aim of this study is to determine whether the ARNWs is beneficial for the enhancement of biological capacity. Clustered ARNWs with a diameter of 200 nm were grown on titanium disks via a three-step synthesis process. Three different types of NWs were generated during the production process, displaying different biological characteristics but similar surface topography and wettability. All of the NW surfaces remarkably accelerated the adsorption of albumin protein; however, compared to the ARNWs, a relatively low level of cell attachment and proliferation occurred on the surfaces of sodium titanate NWs (STiNWs) and H2Ti2O5 nanowires (HTiNWs). The data indicated that the surface titanium oxide crystal structure plays an important role in the cell’s early response. To some extent, the generation of anatase and rutile of the ARNWs compensated for the cell-repelling properties. The crystal structure and potential larger loading capacity of the ARNWs face challenges for enhanced cellular adaptation which could improve its clinical potential.

The effect of changes in surface charge on the biological properties of implants is not clear. The objective of this study was to evaluate the biological properties of the surface of titanium sheets with different charges due to different treatment methods. Titanium sheets were sandblasted with large grit and underwent acid etching before being subsequently divided into the following groups: SLA, no further treatment; SLA-Ca2+, immersed in 1% CaCl2 solution; SLA-NaCl, immersed in saline; and SLA-Ca2+-NaCl, immersed in 1% CaCl2 solution followed by saline. Surface characteristics were evaluated using field-emission scanning electron microscopy with energy-dispersive spectrometry, surface profilometry, and contact angle assays. Additionally, we used a ζ-potential analyzer to directly measure the electrostatic charge on the different group surfaces. The effect of changes in the Ti surface on biological processes after different treatments was determined by analyzing fibronectin adsorption, osteoblast-like MG63 cell adhesion and proliferation, and the expression of osteogenesis-related genes. Compared to the SLA surface, the other three groups contained corresponding trace elements because they were soaked in different liquids; the contact angles of the three groups were not significantly different, but they were significantly smaller than that of the SLA group; and there was no change in the surface topography or roughness. Furthermore, the SLA-Ca2+ group had a significantly reduced negative charge compared to that of the other three groups. There were no differences between the SLA-NaCl and SLA-Ca2+-NaCl groups in terms of negative charge, and the SLA group surface carried the most negative charge. Fibronectin adsorption capacity and cytological performance testing further showed that the SLA-Ca2+ group had the most significant change, followed by the SLA-NaCl and SLA-Ca2+-NaCl groups; the SLA group had significantly lower capacity and performance than the other three groups. These results suggest that the surface charge of the titanium sheet changed when immersed in different liquids and that this treatment enhanced biocompatibility by reducing the electrostatic repulsion between biomaterials and biomolecules.

The Bi2Te3/graphite/polythiophene composites were prepared by solution mixing, mechanical ball milling, cold pressing and spark plasma sintering (SPS) in order to utilize and integrate the high Seebeck coefficient of Bi2Te3, high electrical conductivity of graphite (G) and low thermal conductivity of polythiophene (PTh). The structures and properties of the composites were characterized by scanning electron microscope, thermo gravimetric analyzer, x-ray diffraction and ULVAC ZEM-2 Seebeck coefficient measurement. The results showed that the related components were uniformly dispersed in the composites, and the electrical conductivity of the composites increased significantly with increasing G content. A small addition of Bi2Te3 to the matrix contributed to an increase in Seebeck coefficient and the thermal conductivity of the composites stayed at a low level owing to the low thermal conductivity of PTh. These composites prepared by SPS show an increase in Seebeck coefficient but a decrease in electrical conductivity as compared to corresponding composites prepared by cold pressing.

A series of conjugated poly(3,4-ethylenedioxythiophene methine)s (PEDOT-Ms) with different side groups (e.g., electron-withdrawing, electron-donating, and electron-neutralizing groups) containing 3,4-ethylenedioxythiophene (EDOT) units was synthesized and characterized, showing low optical bandgaps. Then, the PEDOT-M polymers were blended with graphite (G) to prepare polymer–inorganic composites to compare their thermoelectric (TE) properties. The optical absorption study indicated direct bandgaps ranging from 1.72 to 1.79 eV. The results showed that PEDOT-M polymers with strongly electron-withdrawing and electron-donating groups exhibited lower bandgap values and higher Seebeck coefficients, and their composites exhibited better TE properties than PEDOT-M with an electron-neutralizing side group. The highest figure of merit (ZT) value for the (poly[(3,4-ethylenedioxythiophene-2,5-diyl) (p-nitrobenzylidene)(3,4-ethylenedioxythiophenequinodimethane-2,5-diyl)])(PEDOT-NBQ)/80 wt% G composite was 6.75 × 10−3 at 120°C, which was higher than the ZT value of the other PEDOT-M/G composites. These results reveal a novel approach using the structural modifications of polymers to improve the understanding of TE performance and confirm that the conjugated PEDOT-M samples studied are low-bandgap conducting polymers that can be used as TE materials. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

As representative conjugated polymers, the physical properties, such as electric conductivity and electro-optic properties, of poly-Schiff bases (PSBs) have been widely investigated. However, to date, the thermoelectric (TE) properties of PSB or related polymers remain unreported. In this study, PSB with a donor–acceptor structure (PSB(A)) was synthesized and was blended with different fillers to prepare polymer–inorganic TE composites. For comparison, PSB with the common structure (PSB(B)) was also synthesized, and PSB(B)–graphite composites were fabricated. The PSB(A)/graphite composites exhibited a higher power factor of 10.2 μW m−1 K−2 compared with 4.5 μW m−1 K−2 of the PSB(B)/graphite composites at the same doping level. The effects of different fillers on the TE properties of the PSB(A)-based composites were investigated in detail, and the highest TE figure of merit, ZT = 2.53 × 10−3, was obtained. The results show that excellent TE materials could be produced by preparing polymer–inorganic TE composites using novel conducting polymers with a special structure (e.g., donor–acceptor structure) and conducting fillers.

Xianglong Ding,1 Lei Zhou,1 Jingxu Wang,2 Qingxia Zhao,3 Xi Lin,1 Yan Gao,1 Shaobing Li,4 Jingyi Wu,1 Mingdeng Rong,4 Zehong Guo,1 Chunhua Lai,1 Haibin Lu,4 Fang Jia11Center of Oral Implantology, Guangdong Provincial Stomatological Hospital, Southern Medical University, 2Department of Stomatology, The First Affiliated Hospital of Guangzhou Medical University, 3Department of Stomatology, Nanfang Hospital, 4Department of Periodontics and Implantology, Guangdong Provincial Stomatological Hospital, Southern Medical University, Guangzhou, People’s Republic of ChinaAbstract: In the present work, a hierarchical hybrid micro/nanostructured titanium surface was obtained by sandblasting with large grit and acid etching (SLA), and nanotubes of different diameters (30nm, 50nm, and 80nm) were superimposed by anodization. The effect of each SLA-treated surface decorated with nanotubes (SLA+30nm, SLA+50nm, and SLA+80nm) on osteogenesis was studied in vitro and in vivo. The human MG63 osteosarcoma cell line was used for cytocompatibility evaluation, which showed that cell adhesion and proliferation were dramatically enhanced on SLA+30nm. In comparison with cells grown on the other tested surfaces, those grown on SLA+80nm showed an enhanced expression of osteogenesis-related genes. Cell spread was also enhanced on SLA+80nm. A canine model was used for in vivo evaluation of bone bonding. Histological examination demonstrated that new bone was formed more rapidly on SLA-treated surfaces with nanotubes (especially SLA+80nm) than on those without nanotubes. All of these results indicate that SLA+80nm is favorable for promoting the activity of osteoblasts and early bone bonding.Keywords: nanotopography, osseointegration, dental and orthopedic implant, titanium

Many challenges exist in improving early osseointegration, one of the most critical factors in the long-term clinical success of dental implants. Recently, ultraviolet (UV) light-mediated photofunctionalization of titanium as a new potential surface treatment has aroused great interest. This study examines the bioactivity of titanium surfaces treated with UV light of different wavelengths and the underlying associated mechanism. Micro-arc oxidation (MAO) titanium samples were pretreated with UVA light (peak wavelength of 360 nm) or UVC light (peak wavelength of 250 nm) for up to 24 h. UVC treatment promoted the attachment, spread, proliferation and differentiation of MG-63 osteoblast-like cells on the titanium surface, as well as the capacity for apatite formation in simulated body fluid (SBF). These biological influences were not observed after UVA treatment, apart from a weaker effect on apatite formation. The enhanced bioactivity was substantially correlated with the amount of Ti-OH groups, which play an important role in improving the hydrophilicity, along with the removal of hydrocarbons on the titanium surface. Our results showed that both UVA and UVC irradiation altered the chemical properties of the titanium surface without sacrificing its excellent physical characteristics, suggesting that this technology has extensive potential applications and merits further investigation.

Xianglong Ding,1 Xiaoqin Yang,2 Lei Zhou,1 Haibin Lu,1 Shaobing Li,1 Yan Gao,1 Chunhua Lai,1 Ying Jiang11Center of Oral Implantology, 2Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, Guangzhou, People's Republic of ChinaBackground and methods: In this report, layered microporous titanate nanowire scaffolds (TiNWs) were constructed via a hydrothermal route and then decorated with anatase nanocrystals (ANs@TiNWs) by immersion in TiCl4 solution. The diameter and specific surface area of the ANs@TiNWs was measured. The TiNWs and ANs@TiNWs were then compared for their ability to adsorb protein and adhere to MG63 cells.Results: The diameter and specific surface area of the ANs@TiNWs were significantly larger than for TiNWs, and the ANs@TiNWs had an enhanced protein-adsorbing effect. It was found that the MG63 cells were less able to adhere to the flat titanium substrate than the TiNWs and ANs@TiNWs, and that this cell-repellant ability was greater with ANs@TiNWs. Other MG63 cell functions, proliferation in particular, were also inhibited by ANs@TiNWs.Conclusion: ANs@TiNWs show a high protein adsorption and cell-repellant capacity which would be useful in drug delivery.Keywords: protein adsorption, antiadhesion, nanotopography, drug delivery

Alveolar bone loss has long been a challenge in clinical dental implant therapy. Simvastatin (SV) has been demonstrated to exert excellent anabolic effects on bone. However, the successful use of SV to increase bone formation in vivo largely depends on the local concentration of SV at the site of action, and there have been continuing efforts to develop an appropriate delivery system. Specifically, nanostructured lipid carrier (NLC) systems have become a popular type of encapsulation carrier system. Therefore, SV-loaded NLCs (SNs) (179.4 nm in diameter) were fabricated in this study, and the osteogenic effect of the SNs was evaluated in a critical-sized rabbit calvarial defect. Our results revealed that the SNs significantly enhanced bone formation in vivo, as evaluated by hematoxylin and eosin (HE) staining, immunohistochemistry, and a fluorescence analysis. Thus, this novel nanostructured carrier system could be a potential encapsulation carrier system for SV in bone regeneration applications.

Vertical bone regeneration of severe atrophic alveolar ridges remains a challenging procedure in implant dentistry.The aim of this study, accordingly, is to use a rabbit vertical guided bone regeneration model to evaluate whether using a collagen membrane (CM) loaded with small doses of recombinant human bone morphogenetic protein-2 with collagen-binding domain (rhBMP-2/CBD) would enhance two-way vertical bone regeneration. In each of eight rabbits, four titanium cylinders were screwed in perforated slits made into the external cortical bones of the calvaria. The following four treatment modalities were randomly allocated: 1) cylinders filled with mineralized bone matrix and covered with CM/rhBMP-2/CBD; 2) cylinders filled with mineralized bone matrix and covered with CM/rhBMP-2; 3) cylinders filled with mineralized bone matrix and covered with CM alone; or 4) cylinders filled with mineralized bone matrix without a membrane cover.After 6 weeks, the new bones were examined by histologic analysis. Slender new bone trabeculae were observed in the superficial layer of the titanium cylinders covered with CM/rhBMP-2/CBD, and higher degrees of bone were observed in this group compared with the other three groups. The average area fraction of newly formed bone was significantly more in the CM/rhBMP-2/CBD group compared with the CM/rhBMP-2, CM, or the no membrane control groups (all P0.01).The present study demonstrates that CMs loaded with small doses of rhBMP-2/CBD induce new bone formation not only from the surface of the native bone, but also from the superficial structures. The augmented new bone, therefore, is improved in both quantity and quality.

To prepare enteric coated pellets containing panax notoginseng saponins.Panax notoginseng saponins loaded pellets were prepared by Extrusion-Spheronization method, and coated by Eudragit L30D-55 using Glatt fluid bed with the bottom spray process, central composite design was used to optimize the coating prescription.The drug release of enteric coated pellets of panax notoginseng saponins pellets would be lower than 5% in 2 h in simulated gastric fluid, but reach above 85% in 3 h in simulated human gastroenteric environment.The enteric coated pellets of panax notoginseng saponins have good acid residence to avoid panax notoginseng saponins from degrading in gastric acid.

We investigate whether a novel and inexpensive etching method, H3PO4 + NaF, on titanium could obtain both a lower hydrogen content and superior calcium phosphate deposition performance, while achieving similar surface roughness in comparison with the traditional etching method. Pure titanium samples were treated with different concentrations of H3PO4 + NaF at ambient temperature without auxiliary implementations (groups A, B and C), and were treated using the traditional method (group T). The samples were then maintained in simulated body fluid for 10 and 20 days. The surface morphology and chemistry, as well as the hydrogen content and distribution, were studied. The hydrogen content of the new groups are in the range of 31 (3.6)-86.9 (7.2) ppm, and that of group T is 287 (13.5) ppm. The amount of deposited calcium phosphates increases as the hydrogen content approaches 90 ppm; however, this trend does not apply as the hydrogen content exceeds 90 ppm. The surface roughnesses of groups A, B and C are in the range of 0.47 (0.01)-0.92 (0.05) µm. The new surface topography regularly transforms, and the surfaces with round pits exert a better effect on the deposition of calcium phosphates than the surfaces with sharp cusps.