Electrically-Controlled Penicillin/Streptomycin Release from Nanostructured Polypyrrole Coated on Titanium for Orthopedic Implants

2009 ◽  
Vol 151 ◽  
pp. 197-202 ◽  
Author(s):  
Sirinrath Sirivisoot ◽  
Rajesh A. Pareta ◽  
Thomas J. Webster
Keyword(s):  
Photoelectron Spectroscopy ◽  
Orthopedic Implants ◽  
Nanometer Scale ◽  
Force Microscopy ◽  
Atomic Force ◽  
Osteoblast Adhesion ◽  
Antibiotic Release ◽  
Orthopedic Applications ◽  
Scale Roughness

Implant infection leading to revision surgery can be avoided by incorporating controllable antibiotic release from titanium (Ti) implant surfaces. In this study, penicillin/streptomycin (P/S) and dexamethasone (Dex) were successfully immobilized via electropolymerization within polypyrrole membranes coated on the surface of Ti, which is widely used in orthopedic applications. In vitro results showed that greater numbers of osteoblasts adhered on these polymer-coated substrates than on currently-used unmodified Ti. X-ray photoelectron spectroscopy was used to monitor and compare the reaction effectiveness and the yield of electropolymerization. Polypyrrole membranes conjugated with P/S and Dex, and then coated with PLGA, all possessed nanometer scale roughness, as analyzed by atomic force microscopy. In summary, this study demonstrated that drugs incorporated within electroactive polypyrrole membranes, whose release was controlled by applying voltages, supported osteoblast adhesion and could potentially fight bacterial infection.

Silica Nanoparticles to Polish Tooth Surfaces for Caries Prevention

2008 ◽  
Vol 87 (10) ◽  
pp. 980-983 ◽  
Author(s):  
R.M. Gaikwad ◽  
I. Sokolov
Keyword(s):  
Silica Nanoparticles ◽  
Ex Vivo ◽  
Bacterial Attachment ◽  
Nanometer Scale ◽  
Human Teeth ◽  
Cariogenic Bacteria ◽  
Force Microscopy ◽  
Atomic Force ◽  
Tooth Surfaces ◽  
Scale Roughness

Although silica particles have been used for tooth polishing, polishing with nanosized particles has not been reported. Here we hypothesize that such polishing may protect tooth surfaces against the damage caused by cariogenic bacteria, because the bacteria can be easily removed from such polished surfaces. This was tested on human teeth ex vivo. The roughness of the polished surfaces was measured with atomic force microscopy (AFM). A considerably lower nanometer-scale roughness was obtained when silica nanoparticles were used to polish the tooth surfaces, as compared with conventional polishing pastes. Bacterial attachment to the dental surfaces was studied for Streptococcus mutans, the most abundant cariogenic bacteria. We demonstrated that it is easier to remove bacteria from areas polished with silica nanoparticles. The results demonstrate the advantage of using silica nanoparticles as abrasives for tooth polishing.

Fibronectin modified TiO2 nanotubes modulate endothelial cell behavior

2018 ◽  
Vol 33 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Ziyang Jin ◽  
Xufeng Yan ◽  
Guiyong Liu ◽  
Min Lai
Keyword(s):  
Photoelectron Spectroscopy ◽  
Umbilical Vein ◽  
Cell Counting ◽  
Cellular Functions ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Substrate Surfaces ◽  
Umbilical Vein Endothelial Cells

Cardiovascular disease has become a great threat to the health of mankind; current titanium (Ti) stents fail due to late stent thrombosis caused by the lack of re-endothelialization of the Ti stent. The objective of this study was to design a novel cardiovascular Ti implant with improved surface biocompatibility. TiO2 nanotubes with a diameter of 110 nm were anodized at a constant voltage of 30 V, and fibronectin was immobilized onto the TiO2 nanotubes using polydopamine. The element composition, morphology, and wettability of the different substrate surfaces were characterized by x-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and contact angle measurements, respectively, confirming the successful immobilization of fibronectin. In vitro experiments including immunofluorescence staining, Cell Counting Kit-8 (CCK-8), and nitric oxide (NO) and prostacyclin (PGI2) release demonstrate that fibronectin modified TiO2 nanotubes supported cell adhesion, proliferation, and normal cellular functions of human umbilical vein endothelial cells (HUVECs). These methodologies can be applied for future fabrication of cardiovascular stents.

scholarly journals Low Molecular Weight and Polymeric Modifiers as Toughening Agents in Poly(3-Hydroxybutyrate) Films

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2446
Author(s):  
Adriana Nicoleta Frone ◽  
Cristian Andi Nicolae ◽  
Mihaela Carmen Eremia ◽  
Vlad Tofan ◽  
Marius Ghiurea ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Photoelectron Spectroscopy ◽  
Biomedical Applications ◽  
Low Molecular Weight ◽  
Elongation At Break ◽  
Force Microscopy ◽  
In Vitro Biocompatibility ◽  
Atomic Force ◽  
Lower Temperature

The inherent brittleness of poly(3-hydroxybutyrate) (PHB) prevents its use as a substitute of petroleum-based polymers. Low molecular weight plasticizers, such as tributyl 2-acetyl citrate (TAC), cannot properly solve this issue. Herein, PHB films were obtained using a biosynthesized poly(3-hydroxyoctanoate) (PHO) and a commercially available TAC as toughening agents. The use of TAC strongly decreased the PHB thermal stability up to 200 °C due to the loss of low boiling point plasticizer, while minor weight loss was noticed at this temperature for the PHB-PHO blend. Both agents shifted the glass transition temperature of PHB to a lower temperature, the effect being more pronounced for TAC. The elongation at break of PHB increased by 700% after PHO addition and by only 185% in the case of TAC; this demonstrates an important toughening effect of the polymeric modifier. Migration of TAC to the upper surface of the films and no sign of migration in the case of PHO were highlighted by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) results. In vitro biocompatibility tests showed that all the PHB films are non-toxic towards L929 cells and have no proinflammatory immune response. The use of PHO as a toughening agent in PHB represents an attractive solution to its brittleness in the case of packaging and biomedical applications while conserving its biodegradability and biocompatibility.

XPS Analysis and Atomic Force Microscopy Observation of Micro-Liquids Adsorbed on Pure Iron and Copper Surfaces

2004 ◽  
Vol 449-452 ◽  
pp. 1025-1028 ◽  
Author(s):  
Rong Gang Wang ◽  
Mitsuo Kido ◽  
Fumihiro Suzumura
Keyword(s):  
Photoelectron Spectroscopy ◽  
Pure Iron ◽  
Nanometer Scale ◽  
Metallic Surfaces ◽  
Copper Surfaces ◽  
X Ray ◽  
Force Microscopy ◽  
Organic Species ◽  
Atomic Force ◽  
Atomic Force Microscopy Observation

The adsorptive on pure iron and copper surfaces was investigated with angle resolved X-ray photoelectron spectroscopy (ARXPS) and atomic force microscope (AFM). Organic species and a little amount of water (micro-droplets surrounded with nanometer-scale film-like-domains) were detected on the oxidized and/or hydrated metallic surfaces for both specimens and their minute structures were discussed.

MORPHOLOGY OF ADSORBED COLLAGEN LAYERS OBSERVED BY ATOMIC FORCE MICROSCOPY

2009 ◽  
Vol 21 (05) ◽  
pp. 311-316
Author(s):  
Yih-Pey Yang ◽  
Chia-Chi Lin
Keyword(s):  
Atomic Force Microscopy ◽  
Type I Collagen ◽  
Fibrillar Structure ◽  
Collagen Molecule ◽  
Nanometer Scale ◽  
Type I ◽  
Force Microscopy ◽  
Atomic Force

The interaction between cells and biomaterials strongly depends on the assembled structure of collagen adsorption upon the solid surface. Due to its self-assembling property, Type I collagen may aggregate and form fibrils in vivo and in vitro. This study utilizes an atomic force microscope to investigate nanometer-scale organization of adsorbed Type I collagen layers on mica and on poly(methyl methacrylate) (PMMA). We have observed various film morphologies, depending on substrate hydrophobicity and the state of collagen solution used. On mica, the atomic force microscopy (AFM) study obtains dense felt-like structures of randomly distributed assemblies. Images of network-like assemblies composed of interwoven fibrils appear on PMMA. According to the above results, we believe that these assemblies are associated at the interface rather than aggregated in the solution. This work also investigates the adsorbed collagen structure on PMMA after collagen aggregation in solution, to realize the relation between adsorption and aggregation. Consequently, the result exhibits a dendritic fibrillar structure adsorbed on PMMA, following collagen molecule aggregation, to form a fibrillar structure in the solution. This result suggests that the adsorption of aggregates preformed in the solution is preferable to collagen molecules adsorption. This research created all assembled structures of adsorbed collagen layers in nanometer-scale thickness.

Fabrication of micropatterns on polypropylene films via plasma pretreatment combined with UV-initiated graft polymerization

2017 ◽  
Vol 31 (10) ◽  
pp. 1346-1357 ◽  
Author(s):  
Liu Jiang ◽  
Huaming Qian ◽  
Gang Chen ◽  
Chunyan Li ◽  
Guangjun Yan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Graft Polymerization ◽  
Cellular Adhesion ◽  
Hydroxyethyl Methacrylate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Plasma Pretreatment ◽  
Polypropylene Films ◽  
Vitro Analysis

In this study, micropatterns on polypropylene films were fabricated via plasma pretreatment and UV-initiated graft polymerization. Firstly, radio-frequency plasma, which does not significantly influence bulk attributes of substrates due to limited penetration depth, was utilized to activate polypropylene films. Then, different sizes of micropatterns of poly(hydroxyethyl methacrylate) (PHEMA) were fabricated on the polypropylene films via UV-initiated graft polymerization of hydroxyethyl methacrylate by using photo-masks. Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle (CA) were employed to characterize changes of pristine polypropylene films and modified ones in surface morphology, roughness, hydrophilicity, free energy and the surface chemical composition. All of these confirmed the successful grafting of different sizes of PHEMA micropatterns on the polypropylene surface. Furthermore, the influence of PHEMA micropatterns on cell proliferation and cytotoxicity was evaluated in vitro. Analysis of cell behaviour indicated that PHEMA micropatterns of the appropriate size can promote cellular adhesion and proliferation, and the PHEMA-micropatterned polypropylene films had good biocompatibility. The approach presented here provides an alternative to synthesize on the surface of polypropylene films’ micropatterns with the aim of using them in a diverse array of applications.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Targeting Breast Cancer Cells with G4 PAMAM Dendrimers and Valproic Acid Derivative Complexes

2020 ◽  
Vol 20 (15) ◽  
pp. 1857-1872
Author(s):  
Alberto M. Muñoz ◽  
Manuel J. Fragoso-Vázquez ◽  
Berenice P. Martel ◽  
Alma Chávez-Blanco ◽  
Alfonso Dueñas-González ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Cell Lines ◽  
Water Solubility ◽  
Md Simulations ◽  
Pamam Dendrimer ◽  
Pamam Dendrimers ◽  
Force Microscopy ◽  
Micromolar Concentration ◽  
Atomic Force

Background: Our research group has developed some Valproic Acid (VPA) derivatives employed as anti-proliferative compounds targeting the HDAC8 enzyme. However, some of these compounds are poorly soluble in water. Objective: Employed the four generations of Polyamidoamine (G4 PAMAM) dendrimers as drug carriers of these compounds to increase their water solubility for further in vitro evaluation. Methods: VPA derivatives were subjected to Docking and Molecular Dynamics (MD) simulations to evaluate their affinity on G4 PAMAM. Then, HPLC-UV/VIS, 1H NMR, MALDI-TOF and atomic force microscopy were employed to establish the formation of the drug-G4 PAMAM complexes. Results: The docking results showed that the amide groups of VPA derivatives make polar interactions with G4 PAMAM, whereas MD simulations corroborated the stability of the complexes. HPLC UV/VIS experiments showed an increase in the drug water solubility which was found to be directly proportional to the amount of G4 PAMAM. 1H NMR showed a disappearance of the proton amine group signals, correlating with docking results. MALDI-TOF and atomic force microscopy suggested the drug-G4 PAMAM dendrimer complexes formation. Discussion: In vitro studies showed that G4 PAMAM has toxicity in the micromolar concentration in MDAMB- 231, MCF7, and 3T3-L1 cell lines. VPA CF-G4 PAMAM dendrimer complex showed anti-proliferative properties in the micromolar concentration in MCF-7 and 3T3-L1, and in the milimolar concentration in MDAMB- 231, whereas VPA MF-G4 PAMAM dendrimer complex didn’t show effects on the three cell lines employed. Conclusion: These results demonstrate that G4 PAMAM dendrimers are capableof transporting poorly watersoluble aryl-VPA derivate compounds to increase its cytotoxic activity against neoplastic cell lines.

scholarly journals Photocatalytic reduction of graphene oxide with cuprous oxide film under UV-vis irradiation

2020 ◽  
Vol 59 (1) ◽  
pp. 207-214 ◽  
Author(s):  
Yao Wang ◽  
Jianqing Feng ◽  
Lihua Jin ◽  
Chengshan Li
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Photocatalytic Reduction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Reduced Graphene ◽  
Reduction Efficiency ◽  
Metal Organic ◽  
Reduction Effect

AbstractWe have grown Cu2O films by different routes including self-oxidation and metal-organic deposition (MOD). The reduction efficiency of Cu2O films on graphene oxide (GO) synthesized by modified Hummer’s method has been studied. Surface morphology and chemical state of as-prepared Cu2O film and GO sheets reduced at different conditions have also been investigated using atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). Results show that self-oxidation Cu2O film is more effective on phtocatalytic reduction of GO than MOD-Cu2O film. Moreover, reduction effect of self-oxidation Cu2O film to GO is comparable to that of environmental-friendly reducing agent of vitamin C. The present results offer a potentially eco-friendly and low-cost approach for the manufacture of reduced graphene oxide (RGO) by photocatalytic reduction.

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