Polymeric hydrogels have been widely researched as drug delivery systems, wound dressings and tissue engineering scaffolds due to their unique properties such as good biocompatibility, shaping ability and similar properties to extracellular matrix. However, further development of conventional hydrogels for biomedical applications is still limited by their poor mechanical properties and self-healing properties. Currently, nanocomposite hydrogels with excellent properties and customized functions can be obtained by introducing nanoparticles into their network, and different types of nanoparticles, including carbon-based, polymer-based, inorganic-based and metal-based nanoparticle, are commonly used. Nanocomposite hydrogels incorporated with polymeric micelles can not only enhance the mechanical properties, self-healing properties and chemical properties of hydrogels, but also improve the
Biocompatible Materials ; Hydrogels ; Micelles ; Nanocomposites ; Polymers

OBJECTIVES: The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. MATERIALS AND METHODS: Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE) and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH) were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each). Color coordinates (L*a*b*, DeltaL*, Deltaa*, Deltab*, and DeltaE*) were measured using a VITA Easyshade Compact (VITA Zahnfabrik) after 24 hr of storage (baseline) and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control) (n = 7). In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (DeltaE) were calculated and were analyzed by Kruskal-Wallis and Dunn multiple comparison test. RESULTS: The color difference (DeltaE*) of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola (15.28 +/- 2.61) and black tea (12.22 +/- 2.73) showed the highest mean DeltaE* value after 30 day, followed by Filtek Ultimate Universal Restorative (5.99 +/- 1.25) and Filtek Ultimate Flowable (4.71 +/- 1.40) in black tea (p < 0.05). CONCLUSIONS: The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages.
Beverages ; Coca ; Cola ; Compomers ; Immersion ; Nanocomposites ; Silorane Resins ; Tea ; Water

The present study investigates Mg-SiO
Magnesium ; Mandibular Reconstruction ; Materials Testing ; Nanocomposites ; Silicon Dioxide

PURPOSE: This study characterized the synthesis of a modified PMMA (Polymethyl methacrylate) denture acrylic loading platinum nanoparticles (PtN) and assessed its bacterial inhibitory efficacy to produce novel antimicrobial denture base material. MATERIALS AND METHODS: Polymerized PMMA denture acrylic disc (20 mm x 2 mm) specimens containing 0 (control), 10, 50, 100 and 200 mg/L of PtN were fabricated respectively. The obtained platinum-PMMA nanocomposite (PtNC) was characterized by TEM (transmission electron microscopy), SEM/EDX (scanning electron microscope/energy dispersive X-ray spectroscopy), thermogravimetric and atomic absorption spectrophotometer analysis. In antimicrobial assay, specimens were placed on the cell culture plate, and 100 microL of microbial suspensions of S. mutans (Streptococcus mutans) and S. sobrinus (Streptococcus sobrinus) were inoculated then incubated at 37degrees C for 24 hours. The bacterial attachment was tested by FACS (fluorescence-activated cell sorting) analysis after staining with fluorescent probe. RESULTS: PtN were successfully loaded and uniformly immobilized into PMMA denture acrylic with a proper thermal stability and similar surface morphology as compared to control. PtNC expressed significant bacterial anti-adherent effect rather than bactericidal effect above 50 mg/L PtN loaded when compared to pristine PMMA (P=.01) with no or extremely small amounts of Pt ion eluted. CONCLUSION: This is the first report on the synthesis and its antibacterial activity of Pt-PMMA nanocomposite. PMMA denture acrylic loading PtN could be a possible intrinsic antimicrobial denture material with proper mechanical characteristics, meeting those specified for denture bases. For clinical application, future studies including biocompatibility, color stability and warranting the long-term effect were still required.
Absorption ; Cell Culture Techniques ; Denture Bases ; Dentures* ; Nanocomposites ; Nanoparticles* ; Platinum* ; Polymers ; Polymethyl Methacrylate* ; Suspensions

PURPOSE: For a successful partial liver resection, familiarity with the many anatomical variations of the biliary and vascular components in the liver is important. The aim of this study was to fabricate a precisely reproduced model of a human hepatic vascular cast with a very fine structure using elastomeric nanocomposites. METHODS: A model of the vascular structure of the human liver was prepared by injecting elastomeric nanocomposites latex into that of a human liver obtained from a cadaver dissection, followed by cross-linking of the elastomeric nanocomposites, and then leaching out the human tissues using a strong acid solution. RESULTS: A produced new version of human vascular casts, with further improved performances in both the stability and mechanical property, was successfully produced by application of new elastomer nanocomposites techniques based on clay nano particles. The cast showed a much finer vascular structure and lasted longer. This new technique is expected to provide a useful protocol for the investigating of the real vascular structure of the human liver. CONCLUSION: A precisely reproduced vascular cast of the human liver will significantly help to solve surgical complications, such as hepatic congestion-induced vascular injury and bile leakage, and give a more precise simulation for anatomical hepatic resection.
Bile ; Cadaver ; Elastomers* ; Humans ; Latex ; Liver ; Nanocomposites* ; Recognition (Psychology) ; Vascular System Injuries

OBJECTIVETo examine the changes of the mechanical properties of 7 different light-cured composite resins after thermal cycling and the correlations between these properties.

METHODSSeven different light-cured composite resins, including 2 microfilled composites (A110:AH and ESTELITE :ET), 3 microhybrid composites (AELITE:AT, Z250:ZS, and CharmFil plus:CP), and 2 nanohybrid composites (Z350:ZH and Grandio:GD), were prepared into test specimens with a diameter of 12 mm and a thickness of 1.0 mm. The specimens were stored in distilled water at 37 degrees celsius; for 24 h prior to 1 000 thermal cycles of 5 degrees celsius; for 15 s and 55 degrees celsius; for 15 s. The biaxial flexural strength (δ(f)) was tested using the ball-on-three-ball method at a crosshead speed of 0.5 mm/min (ISO4049). The fracture surface was observed under scanning electron microscope (SEM), and the remaining specimens underwent Knoop hardness test with a 50-g loading for 10 s.

RESULTSThe highest and lowest Weibull modulus was observed in AH (18.752) and AT (5.290) group, respectively. The highest and lowest biaxial flexural strength was observed in ZS (158.2 MPa) and ET (54.0 MPa) groups, respectively. The δ(f) of the tested materials decreased in the order of microhybrid composite, nanohybrid composite, and microfiller composite, and the δ(f) showed no significant difference between the composites with a similar filler (P>0.05). The fracture number was positively correlated to the strength of the material. The Knoop hardness numbers (H) was the highest in GD group (110.81∓14.77 kg/mm(2)) and the lowest in AH group (42.81∓1.91 kg/mm(2)). SEM showed that the interface region of the matrix and the filler was vulnerable to crack formation.

CONCLUSIONThe nanohybrid composite resins better suit clinical applications than microhybrid composites. The applicability of Knoop hardness test in hardness measurement of the composite resins needs to be further demonstrated.

Composite Resins ; chemistry ; Materials Testing ; Nanocomposites ; Nanoparticles ; Stress, Mechanical ; Temperature ; Tensile Strength

OBJECTIVETo explore the effects of the gelatin (Gt)/(polycaprolactam) PCL composite nanofiber scaffold on wound healing of full-thickness defect in rabbits.

METHODSSixteen rabbits were inflicted with full-thickness skin open wounds on the back, and they were divided into A group (with treatment of Gt/PCL nanofiber membrane, 8 wounds), B group (with treatment of PCL fiber membrane, 8 wounds), and C group (with treatment of vaseline gauze, 8 wounds), the wounds in A , B groups served as self controls. Wound healing time was recorded. Wound healing rates were calculated on 3, 7, 10 post operation day (POD). Wound specimens and their adjacent skin were examined histologically on 3, 7, and 10 POD.

RESULTSThere was obvious difference in wound healing time among A, B, C groups, and they were (18.2 +/- 1.3) d, (20.3 +/- 1.1) d, (22.0 +/- 0.6) d, respectively. Wound healing rate in A group was obviously higher than that in B, C group on 3, 7, 10 POD (P < 0.05). Compared with those in other groups, the proliferation of granulation tissue in dermis in A group was less, the epidermal cells were proliferated quickly, and collagen was arranged regularly.

CONCLUSIONGt/PCL composite nanofiber membrane can promote wound healing of full-thickness skin defect in rabbits, which is an ideal material for tissue engineering.

Animals ; Caprolactam ; chemistry ; Disease Models, Animal ; Gelatin ; chemistry ; Nanocomposites ; chemistry ; Rabbits ; Tissue Scaffolds ; Wound Healing

OBJECTIVETo study the biocompatibility of porous calcium phosphate ceramics nanocomposite.

METHODSThe biocompatibility was evaluated via experiments including the hemolysis test, hemopexis test, acute systemic toxicity test, pyrogen test, and intramuscular implant test, in which biphasic calcium phosphate nanocomposite (NanoBCP) presented as leaching solution, suspension or blocks of 5 mmx5 mmxl mm. Animals including New Zealand Rabbits, Kunming mice, SD rats were selected as the host.

RESULTSThe hemolysis of NanoBCP was 1.1% (<5%). Four coagulation index levels were within the normal range. In pyrogen test, the temperature of each experimental rat increased by 0.35, 0.40, 0.28 degrees C (<0.60 degrees C, in accordance with the pyrogen-free criterion for biomedical materials). No consequent death, dyspnoea, organ dysfunction, severe peritoneal irritation or ptosis was observed in acute systemic toxic test. Newly-formed fibrous tissue could be found after the implantation.

CONCLUSIONThe material possesses outstanding biocompatibility and degradability with no toxicity or irritation, contains no pyrogen, as well as better degradation properties than biphasic calcium phosphate.

Animals ; Biocompatible Materials ; Calcium Phosphates ; Ceramics ; Hydroxyapatites ; Mice ; Nanocomposites ; Prostheses and Implants ; Rabbits ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo develop novel polyetheretherketone (PEEK) based nanocomposites which possess the favorable antibacterial property, and to investigate the oral microbial adhesion and biofilm formation on the surfaces of PEEK, nano-fluorohydroxyapatite (n-FHA)-PEEK and nano-hydroxyaptite (n-HA)-PEEK.

METHODSThe bacterial adhesion and biofilm formation on the surfaces of n-FHA-PEEK, n-HA-PEEK were investigated via microbial viability assay kit and laser scanning confocal microscope (LSCM), respectively, with pure PEEK as control group.

RESULTSNo significantly statistical difference were found in the bacterial adhesion amounts on the surfaces of n-FHA-PEEK, n-HA-PEEK and PEEK at 1 h and 4 h. However, the number of bacteria on the n-FHA-PEEK surface decreased dramatically at 2 h (0.496 ± 0.008) compared with n-HA-PEEK groups (0.543 ± 0.015, P < 0.01). Although the biofilms formation on surfaces observed by LSCM had similar morphology and thickness at 3, 7, 14 d, that on the n-FHA-PEEK surface showed the highest dead-to-live bacteria ratio among the three materials at 14 d.

CONCLUSIONSThe combination of n-HA, especially for the n-FHA could inhibit the bacteria adhesion and accelerate the bacterial death, eventually may have an influence on the structure of biofilms and reduce the risk of peri-implantitis. Therefore, n-FHA-PEEK nanocomposites presented a good prospect for clinical applications as dental implant materials.

Bacterial Adhesion ; physiology ; Bacterial Load ; Biofilms ; Dental Implants ; microbiology ; Hydroxyapatites ; Ketones ; Nanocomposites ; microbiology ; Polyethylene Glycols

OBJECTIVETo study the microstructure of the Ag-nHA-nTiO2/PA66 membrane and investigate its biocompatibility.

METHODSThe microstructure of Ag-nHA-nTiO2PA66 membrane and e-polytetra fluoroethylene (e-PTFE) membrane were observed by light microscope and scanning electron microscope(SEM). MG63 osteoblast-like cells were cultured on the two kinds of membrane and blank group. The cell proliferation was checked by methyl thiazolyl tetrazolium (MTT) method and alkaline phosphatase (ALP) activity was detected by enzyme linked immunosorbent assay (ELISA). The adhesion and proliferation of the cells on the two kinds of membrane was observed by SEM.

RESULTSThe Ag-nHA-nTiO2/PA66 membrane was composed of the obverse face and the opposite face. The obverse face was porous and the opposite face was smooth. Microstructures of the obverse and the opposite face of the e-PTFE membrane were same. The e-PTFE membrane showed many tiny lined cracks in elliptic structure. MTT assay and ALP measurement showed that there were no significant difference between each of the two membrane groups and the blank (P > 0.05). The adhesion and proliferation of cells on the Ag-nHA-nTiO2/PA66 membrane were better than the e-PTFE membrane.

CONCLUSIONAg-nHA-nTiO2/PA66 membrane has no negative effects on the growth of osteoblast-like cells. Ag-nHA-nTiO/PA66 membrane is biocompatible and its microstructure is appropriate as a guided bone regeneration materials.

Anti-Bacterial Agents ; Bone Regeneration ; Cell Proliferation ; Durapatite ; Nanocomposites ; Nylons ; Osteoblasts