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1.
Chemosphere ; 251: 126440, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32169699

RESUMO

Carbon dots (CDs) are an emerging fluorescent nano-imaging probe due to their unique characteristics, such as good conductivity, carbon-based chemical composition, and photochemical stability, which sets up the potential of outperforming the classic metal-based quantum dots (QDs). It is a timely effort to proactively investigate the biocompatibility feature of CDs with a view to safely utilize this emerging nanomaterial in biological systems. In this study, we assessed the safety profile of an in-house synthesized CDs in hepatocyte-like Hepa 1-6 cells, which represents an important target organ for CDs exposure through either particle uptake and/or accumulation and elimination from primary exposure sites post particle administration. We not only demonstrated a dose- and time-dependent compromised cell viability, but also observed the induction of autophagy at high concentration (i.e. 400 µg mL-1), authenticated by the conversion of microtubule-associated protein light chain 3 (LC3)-I to LC3-II. We attributed these changes as the protective mechanism by which the cells used to compensate for CDs-induced apoptosis and cytotoxicity. The involvement of autophagy was further confirmed because the cytotoxicity profile can be increased or reduced by the use of 3-MA (autophagy inhibitor) and NAC (ROS inhibitor), respectively. Collectively, our findings revealed dose-dependent moderate cytotoxicity in Hepa 1-6 cells. Mechanistic understanding of autophagy during the cellular process revealed the homeostasis when liver cells deal with CDs as an external insult.

2.
BMC Oral Health ; 20(1): 43, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32028960

RESUMO

BACKGROUND: Better understanding of the danger zone anatomy in mesial roots (MRs) of mandibular first molars (MFMs) may serve to decrease the risk of mishaps. This study aimed to measure the minimal distal dentine thicknesses of danger zone in MRs of MFMs in a native Chinese population using cone-beam computed tomography (CBCT). METHODS: CBCT images of 1792 MFMs from 898 Chinese patients were analyzed. The minimal distal dentine thicknesses of the mesiobuccal (MB) and mesiolingual (ML) canals below the furcation 1, 2, 3, 4, 5 mm were measured. The association between the minimal distal dentine thicknesses and the root lengths, patient's age and gender, side were assessed. RESULTS: The minimal distal dentine thicknesses of MB and ML canals are located 3 ∼ 4 mm below the furcation for both men and women. There are no differences between MB and ML canals, while the minimal distal dentine thicknesses of MB and ML canals were higher in men than women (P < 0.05), except at 1 and 3 mm of ML canals (P > 0.05). The minimal distal dentine thicknesses of MB and ML canals increased with age in both men and women at each location (P < 0.05). The minimum distal dentine thickness at every location were significantly different between long teeth and short teeth both in men and women (P < 0.05), with short teeth having the smallest mean values. There are no significant differences between two sides (P > 0.05). CONCLUSIONS: The minimal distal dentine thicknesses of MRs in MSMs have close correlation with root length, patient's age and gender.

3.
Sci Total Environ ; 702: 134994, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31715400

RESUMO

In recent years, nanomaterials have been widely applied in electronics, food, biomedicine and other fields, resulting in increased human exposure and consequent research focus on their biological and toxic effects. Mitochondria, the main target organelle for nanomaterials (NM), play a critical role in their toxic activities. Several studies to date have shown that nanomaterials cause alterations in mitochondrial morphology, mitochondrial membrane potential, opening of the mitochondrial permeability transition pore (MPTP) and mitochondrial respiratory function, and promote cytochrome C release. An earlier mitochondrial toxicity study of NMs additionally reported induction of mitochondrial dynamic changes. Here, we have reviewed the mitochondrial toxicity of NMs and provided a scientific basis for the contribution of mitochondria to the toxicological effects of different NMs along with approaches to reduce mitochondrial and, consequently, overall toxicity of NMs.


Assuntos
Exposição Ambiental/estatística & dados numéricos , Nanoestruturas , Humanos , Mitocôndrias , Proteínas de Transporte da Membrana Mitocondrial
4.
Dose Response ; 17(4): 1559325819878585, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31662709

RESUMO

Microneedle (MN) delivery system has been greatly developed to deliver drugs into the skin painlessly, noninvasively, and safety. In the past several decades, various types of MNs have been developed by the newer producing techniques. Briefly, as for the morphologically, MNs can be classified into solid, coated, dissolved, and hollow MN, based on the transdermal drug delivery methods of "poke and patch," "coat and poke," "poke and release," and "poke and flow," respectively. Microneedles also have other characteristics based on the materials and structures. In addition, various manufacturing techniques have been well-developed based on the materials. In this review, the materials, structures, morphologies, and fabricating methods of MNs are summarized. A separate part of the review is used to illustrate the application of MNs to deliver vaccine, insulin, lidocaine, aspirin, and other drugs. Finally, the review ends up with a perspective on the challenges in research and development of MNs, envisioning the future development of MNs as the next generation of drug delivery system.

5.
ACS Omega ; 4(2): 2750-2757, 2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-31459509

RESUMO

A water contact angle greater than 150° together with a sliding angle less than 10° is a special surface phenomenon that appears on superhydrophobic surfaces. In this paper, a brief introduction of the development history and present research on superhydrophobic surfaces was given. Polymeric superhydrophobic surfaces with biomimetic hierarchical roughness were fabricated by a simple method of hot embossing without any chemical treatments. Stainless steel meshes with different mesh numbers were used as template. Moreover, the influences of processing parameters, including mesh number, mold temperature, and pressure, were deeply investigated. Hierarchical microplatforms, microfibers, and oriented arrayed nanowrinkles structure on them, which were resembled with the nanowrinkles structure and hierarchical roughness on a red rose petal, were observed by a scanning electron microscope. A water contact angle of 154° can be achieved after parameter optimization. The method proposed in this study offered a fine and affordable choice for the fabrication of polymeric superhydrophobic surfaces. With the rapid development of functional applications in micro- and nanodevices, this method will show greater superiority in large-area and large-scale production due to its advantages of low cost, high efficiency, and high reliability.

6.
Polymers (Basel) ; 11(1)2019 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-30960040

RESUMO

Electrically conductive polymer composites are in high demand for modern technologies, however, the intrinsic brittleness of conducting conjugated polymers and the moderate electrical conductivity of engineering polymer/carbon composites have highly constrained their applications. In this work, super high electrical conductive polymer composites were produced by a novel hot embossing design. The polydimethylsiloxane (PDMS) composites containing short carbon fiber (SCF) exhibited an electrical percolation threshold at 0.45 wt % and reached a saturated electrical conductivity of 49 S/m at 8 wt % of SCF. When reducing the sample thickness from 1.0 to 0.1 mm by the hot embossing process, a compression-induced percolation threshold occurred at 0.3 wt %, while the electrical conductivity was further enhanced to 378 S/m at 8 wt % SCF. Furthermore, the addition of a second nanofiller of 1 wt %, such as carbon nanotube or conducting carbon black, further increased the electrical conductivity of the PDMS/SCF (8 wt %) composites to 909 S/m and 657 S/m, respectively. The synergy of the densified conducting filler network by the mechanical compression and the hierarchical micro-/nano-scale filler approach has realized super high electrically conductive, yet mechanically flexible, polymer composites for modern flexible electronics applications.

7.
Polymers (Basel) ; 11(2)2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30960171

RESUMO

This article reviews recent advances in conductive polymer composites from renewable resources, and introduces a number of potential applications for this material class. In order to overcome disadvantages such as poor mechanical properties of polymers from renewable resources, and give renewable polymer composites better electrical and thermal conductive properties, various filling contents and matrix polymers have been developed over the last decade. These natural or reusable filling contents, polymers, and their composites are expected to greatly reduce the tremendous pressure of industrial development on the natural environment while offering acceptable conductive properties. The unique characteristics, such as electrical/thermal conductivity, mechanical strength, biodegradability and recyclability of renewable conductive polymer composites has enabled them to be implemented in many novel and exciting applications including chemical sensors, light-emitting diode, batteries, fuel cells, heat exchangers, biosensors etc. In this article, the progress of conductive composites from natural or reusable filling contents and polymer matrices, including (1) natural polymers, such as starch and cellulose, (2) conductive filler, and (3) preparation approaches, are described, with an emphasis on potential applications of these bio-based conductive polymer composites. Moreover, several commonly-used and innovative methods for the preparation of conductive polymer composites are also introduced and compared systematically.

8.
Sensors (Basel) ; 19(6)2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30901966

RESUMO

A new type of flexible sensor, which could maintain the deformation consistency and achieve the real-time detection of the variation in load of the measured object, was proposed in this work. According to the principle of forced assembly, PDMS was used as the substrate of sensitive components and electrodes, while carbon fiber was added as a conductive medium to prepare a polymer-based flexible sensor, which effectively overcame the deformation limitation and output instability of conventional flexible sensors due to different substrates of sensitive components and the electrode. Combined with the sensor structure and the forced assembly method, a theoretical analysis of its conductive measurement mechanism was carried out. Meanwhile, an experimental test device was designed to test and analyze the output characteristics of the flexible sensor under a static and dynamic alternating load. The results show that the flexible sensor exhibited linear output under the dynamic alternating load of 10 kN to 60 kN and frequency of 3 Hz. Peak and valley value had the same phase with the load extremes. The dynamic and static experiments show that the resistance output signal and the sensitivity was in the range of 310~624.15 Ω and 171⁻183 N/Ω respectively. However, due to the hysteresis of the elastic recovery of the polymer, the output repeatability of the flexible sensor under the dynamic alternating load was 5.03% and 0.78% lower than that of the static load, respectively. Combined with the static and dynamic experiments, it was verified that the polymer-based flexible sensor can maintain the same deformation characteristics with the measured object, and at the same time outputted a resistance signal with a certain mapping relationship with the applied load. The repeatability of the output signal under dynamic and static experiments was within ±7%, which can meet the measurement requirements of the fatigue life of the measured body during periodic load.

9.
Cleft Palate Craniofac J ; 56(7): 936-943, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30621447

RESUMO

OBJECTIVE: To compare osseous outcomes of block and cancellous iliac bone grafting in older unilateral alveolar cleft patients. DESIGN: Retrospective and observational follow-up study. SETTING: Cleft Lip and Palate Centre, Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, China. PATIENTS: Forty-five nonsyndromic patients with unilateral complete alveolar cleft were enrolled in this study (25 patients in block bone graft group and 20 patients in cancellous bone graft group). INTERVENTIONS: In cancellous bone graft group, the alveolar cleft was filled with iliac cancellous bone particulate. In group of block bone graft, the harvested bone block was trimmed and fixed in alveolar defect. MAIN OUTCOME MEASURES: A novel method was proposed to investigate the volume and density of residual bone graft at 1-week, 3- and 6-month, 1- and 2-year postoperatively based on cone beam computed tomography scans. RESULTS: No difference in bone graft volume was found between 2 groups at 1-week and 3-month postoperatively; however, the residual volume of block bone graft group was significantly larger than that of cancellous bone graft group at 6-month, 1- and 2-year postoperatively. The bone density of block bone graft group was lower at 1-week and 3-month postoperatively but was comparable at 6-month, 1- and 2-year postoperatively. Our method was reliable and accurate to identify the range of residual bone graft when the boundary of grafted bone could not be identified clearly. CONCLUSION: Block bone graft could achieve comparable bone density and retain a greater amount of residual bone comparing to cancellous bone graft.

10.
BMC Oral Health ; 18(1): 164, 2018 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-30285721

RESUMO

BACKGROUND: Maxillary posterior teeth have close anatomical proximity to the maxillary sinus floor (MSF), and the race, gender, age, side and presence/absence of adjacent teeth may influence the mean distances between the root apices and the MSF. This study aimed to evaluate both the relationship between the maxillary posterior teeth and MSF, and the influence of adjacent teeth loss on the distance between the maxillary posterior roots and MSF. METHODS: Cone-beam computed tomography images were collected from 1011 Chinese patients. The relationship between the maxillary posterior teeth and the MSF was divided into three types: Type OS (the root apex extending below/outside the MSF), Type CO (the root apex contacting with the MSF), Type IS (the root apex extending above/inside the MSF). The minimum vertical distances between the maxillary posterior roots apices and the MSF were recorded. The correlations of the distances with gender and age were analyzed. The distances between the maxillary posterior root apices and the MSF with different types of adjacent teeth loss was evaluated. RESULTS: Type OS was the most common relationship of all posterior root apices (P<0.05). Type IS was highest in the palatal roots (PRs) of the maxillary first molars (MFMs) and the mesiobuccal roots (MBRs) of the maxillary second molars (MSMs) (24.8% and 21.6%) (P<0.05). The frequency of Type IS decreased with age except the premolar roots and PRs of the MSMs (P<0.05). The MBRs of the MSMs had the lowest distances to the MSF (0.8 ± 2.5 mm), followed by the distobuccal roots of the MSMs (1.3 ± 2.7 mm) and the PRs of the MFMs (1.4 ± 3.4 mm) (P<0.05). Age was an important influencing factor to the mean distances while gender had little effects. The distance between the maxillary second premolar root apices and the MSF decreased with the absence of adjacent teeth (P<0.05). CONCLUSIONS: The maxillary molars showed greater proximity to the MSF than premolars. Age had significant impacts on the relationship between maxillary posterior roots and MSF. The absence of maxillary first molars will influence the proximity of maxillary second premolar root apices to MSF.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Maxila/diagnóstico por imagem , Seio Maxilar/diagnóstico por imagem , Dente Molar/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Maxila/anatomia & histologia , Seio Maxilar/anatomia & histologia , Pessoa de Meia-Idade , Dente Molar/anatomia & histologia
11.
Molecules ; 23(9)2018 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-30217082

RESUMO

Investigation of cell behavior under different environments and manual operations can give information in specific cellular processes. Among all cell-based analysis, single-cell study occupies a peculiar position, while it can avoid the interaction effect within cell groups and provide more precise information. Microfluidic devices have played an increasingly important role in the field of single-cell study owing to their advantages: high efficiency, easy operation, and low cost. In this review, the applications of polymer-based microfluidics on cell manipulation, cell treatment, and cell analysis at single-cell level are detailed summarized. Moreover, three mainly types of manufacturing methods, i.e., replication, photodefining, and soft lithography methods for polymer-based microfluidics are also discussed.


Assuntos
Técnicas Analíticas Microfluídicas/instrumentação , Análise de Célula Única/métodos , Animais , Humanos , Polímeros/química
12.
Molecules ; 23(7)2018 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-30002333

RESUMO

Photodynamic therapy (PDT) is able to non-invasively treat and diagnose various cancers and nonmalignant diseases by combining light, oxygen, and photosensitizers (PSs). However, the application of PDT is hindered by poor water solubility and limited light-penetration depth of the currently available photosensitizers (PSs). Water solubility of PSs is crucial for designing pharmaceutical formulation and administration routes. Wavelength of light source at visible range normally has therapeutic depth less than 1 mm. In this review, focus is on the recent research progress of metal-based nanoparticles being applied in PDT. The potential toxicity of these nanoscales and future directions are further discussed.


Assuntos
Nanopartículas Metálicas/uso terapêutico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Animais , Humanos
13.
Nanotechnology ; 29(35): 355304, 2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-29897348

RESUMO

Multifunctional electronics are attracting great interest with the increasing demand and fast development of wearable electronic devices. Here, we describe an epidermal strain sensor based on an all-carbon conductive network made from multi-walled carbon nanotubes (MWCNTs) impregnated with poly(dimethyl siloxane) (PDMS) matrix through a vacuum filtration process. An ultrasonication treatment was performed to complete the penetration of PDMS resin in seconds. The entangled and overlapped MWCNT network largely enhances the electrical conductivity (1430 S m-1), uniformity (remaining stable on different layers), reliable sensing range (up to 80% strain), and cyclic stability of the strain sensor. The homogeneous dispersion of MWCNTs within the PDMS matrix leads to a strong interaction between the two phases and greatly improves the mechanical stability (ca. 160% strain at fracture). The flexible, reversible and ultrathin (<100 µm) film can be directly attached on human skin as epidermal strain sensors for high accuracy and real-time human motion detection.


Assuntos
Epiderme/fisiologia , Nanotubos de Carbono/química , Papel , Dimetilpolisiloxanos/química , Condutividade Elétrica , Humanos , Movimento (Física) , Nanotubos de Carbono/ultraestrutura , Estresse Mecânico , Termogravimetria
14.
Sci Rep ; 8(1): 5438, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29615712

RESUMO

Sub-wavelength antireflection moth-eye structures were fabricated with Nickel mold using Roll-to-Plate (R2P) ultraviolet nanoimprint lithography (UV-NIL) on transparent polycarbonate (PC) substrates. Samples with well replicated patterns established an average reflection of 1.21% in the visible light range, 380 to 760 nm, at normal incidence. An excellent antireflection property of a wide range of incidence angles was shown with the average reflection below 4% at 50°. Compared with the unpatterned ultraviolet-curable resin coating, the resulting sub-wavelength moth-eye structure also exhibited increased hydrophobicity in addition to antireflection. This R2P method is especially suitable for large-area product preparation and the biomimetic moth-eye structure with multiple performances can be applied to optical devices such as display screens, solar cells, or light emitting diodes.


Assuntos
Biomimética/instrumentação , Olho , Mariposas , Dispositivos Ópticos , Animais , Desenho de Equipamento , Cimento de Policarboxilato , Espalhamento de Radiação , Propriedades de Superfície
15.
Polymers (Basel) ; 10(5)2018 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-30966540

RESUMO

The increasing demand for environmental protection has led to the rapid development of greener and biodegradable polymers, whose creation provided new challenges and opportunities for the advancement of nanomaterial science. Biodegradable polymer materials and even nanofillers (e.g., natural fibers) are important because of their application in greener industries. Polymers that can be degraded naturally play an important role in solving public hazards of polymer materials and maintaining ecological balance. The inherent shortcomings of some biodegradable polymers such as weak mechanical properties, narrow processing windows, and low electrical and thermal properties can be overcome by composites reinforced with various nanofillers. These biodegradable polymer composites have wide-ranging applications in different areas based on their large surface area and greater aspect ratio. Moreover, the polymer composites that exploit the synergistic effect between the nanofiller and the biodegradable polymer matrix can lead to enhanced properties while still meeting the environmental requirement. In this paper, a broad review on recent advances in the research and development of nanofiller reinforced biodegradable polymer composites that are used in various applications, including electronics, packing materials, and biomedical uses, is presented. We further present information about different kinds of nanofillers, biodegradable polymer matrixes, and their composites with specific concern to our daily applications.

16.
PLoS One ; 12(8): e0182583, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28787004

RESUMO

Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for drug delivery and mineralization induction. They can load silver and exhibit significantly antibacterial effects. However, the effects of MCSNs and silver-loaded MCSNs on dentin are unknown. The silver (Ag) and/or zinc (Zn) incorporated MCSNs (Ag-Zn-MCSNs) were prepared by a template method, and their characterizations were tested. Then the nanoparticles were filled into root canals and their effects on the dentin were investigated. Ag-Zn-MCSNs showed characteristics of mesoporous materials and sustained release of ions over time. Ag-Zn-MCSNs adhered well to the root canal walls and infiltrated into the dentinal tubules after ultrasound activation. Ag-Zn-MCSNs showed no significantly negative effects on either the flexural strength or the modulus of elasticity of dentin, while CH decreased the flexural strength of dentin significantly (P<0.05). These findings suggested that Ag and Zn can be incorporated into MCSNs using a template method, and the Ag-Zn-MCSNs may be developed into a new disinfectant for the root canal and dentinal tubules.


Assuntos
Materiais Biocompatíveis/farmacologia , Compostos de Cálcio/química , Dentina/efeitos dos fármacos , Fenômenos Mecânicos/efeitos dos fármacos , Nanopartículas/química , Silicatos/química , Prata/química , Zinco/química , Materiais Biocompatíveis/química , Fenômenos Biomecânicos/efeitos dos fármacos , Dentina/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Porosidade
17.
J Int Med Res ; 45(2): 830-842, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28351286

RESUMO

Objective To evaluate the root and root canal morphology of the maxillary second molars (MSMs) in a native Chinese population by cone-beam computed tomography. Methods Cone-beam computed tomography images of 2412 MSMs from 1294 Chinese patients were analyzed to determine the number and morphology of the roots, the root canal morphology, the bilateral symmetry, and the correlations of these parameters with sex and age. Results The percentage of fused roots increased with age, while the percentage of fused roots in women was higher than that in men. The percentage of second mesiobuccal (MB2) canals in MSMs with three separate roots was higher in men than women. Patients aged 31 to 40 years showed a higher prevalence of MB2 canals, while those aged ≥51 years showed the lowest prevalence of MB2 canals among both men and women. There was a significant difference in bilateral symmetry of MSMs between men and women. Conclusion Root fusion of MSMs increased with age, while the root canal morphology was more complex in patients of intermediate ages.


Assuntos
Cavidade Pulpar/anatomia & histologia , Maxila/anatomia & histologia , Dente Molar/anatomia & histologia , Raiz Dentária/anatomia & histologia , Adulto , Fatores Etários , Idoso , Grupo com Ancestrais do Continente Asiático , Tomografia Computadorizada de Feixe Cônico , Cavidade Pulpar/diagnóstico por imagem , Feminino , Humanos , Masculino , Maxila/diagnóstico por imagem , Pessoa de Meia-Idade , Dente Molar/diagnóstico por imagem , Fatores Sexuais , Raiz Dentária/diagnóstico por imagem
18.
Dent Mater J ; 34(1): 54-60, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25748459

RESUMO

Ag-loaded mesoporous bioactive glass (Ag-MBG) powders were synthesized and characterized. The ions release of Ag-MBGs in Tris-HCl and the pH stability of simulated body fluids after immersing Ag-MBGs were tested. Root canals were inoculated with Enterococcus faecalis for 4 weeks, and the antibacterial activity of MBGs, Ag-MBGs and calcium hydroxide against E. faecalis biofilm were evaluated. Results showed that Ag-MBGs possessed highly ordered mesoporous structure with silver nanoparticles deposited in the mesopores, which enabled a sustained Ag ions released. The biofilms treated with Ag-MBGs showed a significant structural disruption compared with MBGs. These results indicated that Ag-MBGs possess a potent antibacterial effect against E.faecalis biofilm in root canal, and the antibacterial activity was induced by the release of Ag ions from Ag-MBGs.


Assuntos
Antibacterianos/química , Biofilmes/efeitos dos fármacos , Cavidade Pulpar/microbiologia , Enterococcus faecalis/efeitos dos fármacos , Vidro/química , Prata/química , Antibacterianos/síntese química , Humanos , Concentração de Íons de Hidrogênio , Porosidade
19.
Int J Nanomedicine ; 9: 5217-30, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25419127

RESUMO

Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials for controlled drug delivery and mineralization induction. Nanosilver-incorporated MCSNs (Ag-MCSNs) were prepared in the present study using both the adsorption and template methods. Both versions of Ag-MCSNs showed characteristic morphology of mesoporous materials and exhibited sustained release of ions over time. In antibacterial testing against planktonic Enterococcus faecalis, Ag-MCSNs showed significantly better antibacterial effects when compared with MCSNs (P<0.05). The Ag-MCSNs aggregated on the dentin surface of root canal walls and infiltrated into dentinal tubules after ultrasound activation, significantly inhibiting the adherence and colonization of E. faecalis on dentin (P<0.05). Despite this, Ag-MCSNs with templated nanosilver showed much lower cytotoxicity than Ag-MCSNs with adsorbed nanosilver (P<0.05). The results of the present study indicated that nanosilver could be incorporated into MCSNs using the template method. The templated nanosilver could release silver ions and inhibit the growth and colonization of E. faecalis both in the planktonic form and as biofilms on dentin surfaces as absorbed nanosilver. Templated Ag-MCSNs may be developed into a new intracanal disinfectant for root canal disinfection due to their antibacterial ability and low cytotoxicity, and as controlled release devices for other bioactive molecules to produce multifunctional biomaterials.


Assuntos
Antibacterianos/farmacologia , Cálcio/química , Dentina/microbiologia , Nanopartículas Metálicas/química , Silicatos/química , Prata/farmacologia , Antibacterianos/química , Aderência Bacteriana/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cavidade Pulpar/citologia , Cavidade Pulpar/efeitos dos fármacos , Cavidade Pulpar/microbiologia , Dentina/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Dente Molar/efeitos dos fármacos , Porosidade , Prata/química
20.
J Endod ; 40(2): 285-90, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24461420

RESUMO

INTRODUCTION: The purpose of this study was to evaluate the antibacterial efficacy of silver nanoparticles (AgNPs) as an irrigant or medicament against Enterococcus faecalis biofilms formed on root dentin. METHODS: Dentin sections were inoculated with E. faecalis for 4 weeks to establish a standard monospecies biofilm model. These biofilms were tested in 2 stages. In stage 1, the biofilms were irrigated with 0.1% AgNP solution, 2% sodium hypochlorite, and sterile saline for 2 minutes, respectively. In stage 2, the biofilms were treated with AgNP gel (0.02% and 0.01%) and calcium hydroxide for 7 days. The ultrastructure of one half of the specimens from each group was evaluated by using scanning electron microscopy, whereas the structure and distribution of viable bacteria of the other half of the specimens were assessed with confocal laser scanning microscopy combined with viability staining. RESULTS: Syringe irrigation with 0.1% AgNP solution did not disrupt the biofilm structure, and the proportion of viable bacteria in the biofilm structures was not different from that of the saline group (P > .05) but was less than that of the control group (P < .05). The biofilms treated with 0.02% AgNP gel as medicament significantly disrupted the structural integrity of the biofilm and resulted in the least number of post-treatment residual viable E. faecalis cells compared with 0.01% AgNP gel and calcium hydroxide groups (P < .05). CONCLUSIONS: The findings from this study suggested that the antibiofilm efficacy of AgNPs depends on the mode of application. AgNPs as a medicament and not as an irrigant showed potential to eliminate residual bacterial biofilms during root canal disinfection.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Enterococcus faecalis/efeitos dos fármacos , Nanopartículas Metálicas/uso terapêutico , Prata/farmacologia , Antibacterianos/administração & dosagem , Hidróxido de Cálcio/farmacologia , Dentina/microbiologia , Corantes Fluorescentes , Géis , Humanos , Teste de Materiais , Nanopartículas Metálicas/administração & dosagem , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Confocal , Microscopia Eletrônica de Varredura , Irrigantes do Canal Radicular/administração & dosagem , Irrigantes do Canal Radicular/farmacologia , Prata/administração & dosagem , Hipoclorito de Sódio/farmacologia , Soluções , Raiz Dentária/microbiologia
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