This paper provides a brief overview of the current research activities which focused on the bio-application of gold magnetic nanocomposite particles. By combining the magnetic characteristics of the iron oxide core with the unique features of nano-gold particles such as targeting by surface modification and optical properties, such composite nanoparticles have a wide range of applications in cancer hyperthermia, CT and MRI imaging, bio-separation, bio sensors, gene diagnosis, drug targeting and many other biomedical fields.
Diagnostic Imaging ; Drug Delivery Systems ; Ferric Compounds ; chemistry ; Gold ; chemistry ; Humans ; Magnetics ; Nanocomposites ; chemistry ; Nanoparticles ; chemistry ; Neoplasms

OBJECTIVETo study environment-friendly determination of azobenzene in trace amounts using beta-cyclodextrin (beta-CD)-modified Au electrode.

METHODSbeta-CD-modified Au electrode was fabricated with a two-step approach, and then a gold electrode modified with beta-CD was used to detect azobenzene by employing Osteryoung square wave voltammetry.

RESULTSThe modified electrode could detect azobenzene, showing a good linearity between the electrochemical current and concentration.

CONCLUSIONAlthough the electrochemical current is related with concentration, the detection limit is around 1.0 x 10(-10) mol/L. This study may provide a new environment-friendly approach for monitoring water quality.

Azo Compounds ; analysis ; chemistry ; Electrochemistry ; Electrodes ; Environmental Monitoring ; instrumentation ; methods ; Gold ; chemistry ; Reproducibility of Results ; Sensitivity and Specificity ; Water Supply ; analysis ; standards ; beta-Cyclodextrins ; chemistry

In order to immobilize myoglobin (Mb) monoclonal antibody on gold film solid-phase carrier, we grew a mixed self-assembled monolayers (SAMs) of acid thiol and mercapto ethanol on gold film. Then we analyzed the property of the sample by atomic force microscopy and X-ray photoelectron spectroscopy. Then, we used 1-(3-dimethyl aminopropyl)-3-ethyl carbodiimide hydrochloride as catalyst to couple SAMs with amino of antibody so that we immobilized antibody on surface of gold film, followed by detecting myoglobin antigen. Results showed that, by optimizing experimental conditions, when we treated gold film by a mixture of mercapto hexadecanoic acid and mercapto undecanol ethanol solution of concentration of 50 mmol/L at temperature of 60 degrees C for 3 hours, and Mb monoclonal antibody of concentration of 40 mg/L for 3 hours, respectively, antibody had high immobilization efficiency and the MbAg was detected to 30 microg/L. The method provided a theoretical and practical basis for using magnetoresistence biosensors to diagnosis myocardial infarction.
Antibodies, Immobilized ; Antibodies, Monoclonal ; immunology ; Biosensing Techniques ; instrumentation ; methods ; Gold ; chemistry ; Humans ; Membranes, Artificial ; Microscopy, Atomic Force ; Myocardial Infarction ; diagnosis ; Myoglobin ; blood ; immunology ; Photoelectron Spectroscopy ; Sulfhydryl Compounds ; chemistry

Antirheumatic gold compounds have been shown to inhibit NF-kB activation by blocking IkB kinase (IKK) activity. To examine the possible inhibitory mechanism of gold compounds, we expressed wild type and mutant forms of IKk alpha and beta subunits in COS-7 cells and determined the effect of gold on the activity of these enzymes both in vivo and in vitro. Substitution of Cys-179 of IKK beta with alanine (C179A) rendered the enzyme to become resistant to inhibition by a gold compound auranofin, however, similar protective effect was not observed with an equivalent level of IKK alpha (C178A) mutant expressed in the cells. Auranofin inhibited constitutively active IKK alpha and beta and variants; IKK alpha (S176E, S180E) or IKK beta (S177E, S181E), suggesting that gold directly cause inhibition of activated enzyme. The different inhibitory effect of auranofin on IKK alpha (C178A) and IKK beta (C179A) mutants indicates that gold could inhibit the two subunits of IKK in a different mode, and the inhibition of NF- kB and IKK activation induced by inflammatory signals in gold-treated cells appears through its interaction with Cys-179 of IKK beta.
Amino Acid Substitution ; Animals ; Auranofin/*pharmacology ; COS Cells ; Cysteine/genetics/*metabolism ; Enzyme Activation/drug effects ; Gold Compounds/*pharmacology ; Protein Subunits/chemistry ; Protein-Serine-Threonine Kinases/*antagonists & inhibitors/chemistry/genetics/*metabolism ; Sulfhydryl Compounds/pharmacology

Gold compounds depress phagocytic cell responses, including chemotaxis, and respiratory burst. However, the effects of gold compounds on the function of phagocytic cells are variable according to the preparation of medicine. In this study, effect of tetrachloroauric acid on activated neutrophil responses, including respiratory burst, lysosomal enzyme release and change of intracellular Ca2+ level and on the synthesis of interleukin-8 and granulocyte-macrophage colony stimulating factor by macrophages was studied. This study further examines how gold compounds affect the activation processes. The respiratory burst stimulated by complement C5a, degraded IgG and PMA in neutrophils was inhibited by tetrachloroauric acid. In contrast to C5a and degraded IgG, PMA-stimulated superoxide production was weakly inhibited by tetrachloroauric acid. Staurosporine, genistein, EGTA and verapamil inhibited superoxide and H2O2 production caused by C5a and degraded IgG. PMA-stimulated superoxide production was inhibited by staurosporine but was not affected by genistein. Tetrachloroauric acid, genistein, EGTA and verapamil inhibited the release of acid phosphatase and myeloperoxidase, while the effect of staurosporine was not detected. The synthesis of interleukin-8 and granulocyte-macrophage colony stimulating factor by interleukin-1beta in macrophages was inhibited by tetrachloroauric acid. Preincubation with tetrachloroauric acid, genistein, EGTA and verapamil, the elevation of (Ca2+)i evoked by C5a was inhibited. Store-regulated Ca2+ entry in thapsigargin-pretreated neutrophils was decreased by the addition of tetrachloroauric acid and genistein. The effect of staurosporine on intracellular Ca2+ mobilization was not observed. In conclusion, tetrachloroauric acid may suppress neutrophil responses through its inhibitory action on elevation of intracellular Ca2+ level and protein kinase C. It might exhibit an inhibitory effect on the action of protein tyrosine kinase. Tetrachloroauric acid depresses cytokine production by macrophages.
Acid Phosphatase ; Chemotaxis ; Colony-Stimulating Factors ; Complement C5a ; Egtazic Acid ; Genistein ; Gold Compounds ; Immunoglobulin G ; Interleukin-1beta ; Interleukin-8 ; Macrophages ; Neutrophils ; Peroxidase ; Phagocytes* ; Protein Kinase C ; Protein-Tyrosine Kinases ; Respiratory Burst ; Staurosporine ; Superoxides ; Verapamil

A long-lasting allergic patch test reaction (LLAPTR) is generally defined as a positive patch test reaction that persists for weeks or months, at least 2 weeks after application of the allergen. Several allergens, including gold sodium thiosulfate, have been reported as causes of LLAPTR, however, it has never been described in the Korean dermatologic literature. We report a case of LLAPTR to Cl+Me-Isothiazolinone (Kathon CG) and p-tert-butylphenol formaldehyde resin (PTBP-FR) in a 45-year-old woman with suspected allergic contact dermatitis.
Allergens ; Dermatitis, Allergic Contact ; Female ; Formaldehyde ; Gold Sodium Thiosulfate ; Humans ; Middle Aged ; Patch Tests ; Resins, Synthetic ; Thiazoles ; Thiosulfates

The purpose of this study was to compare the casting problem and corrosion behavior in two types of HL Hexed abutments of the Steri-Oss system : gold/plastic coping and gold coping. The anodic Polarization behavior, the galvanic corrosion between abutments and Type III gold alloys, before and after casting were analyzed, and the crevice corrosion of casting samples was analyzed with the CPPT test and the SEM. The results are as follows ; 1. Anodic polarization behavior of samples ; Before casting, gold/plastic coping and gold coping was shown to have a similar corrosion patterns. TypeIII casting gold alloy was shown to have a lower corrosion potential and passivation film. Corrosion potential of the case of gold/plastic coping after casting was higher than that of gold coping, but the region of passivation film for gold/plastic coping was smaller than that of gold coping. 2. Galvanic corrosion behavior of samples ; Contact current density between casting gold alloys and gold/plastic before casting was higher than that between gold coping and casting gold alloy. Galvanic corrosion of samples after casting was shown to have similar contact current density. 3. Crevice corrosion behavior of samples ; Crevice corrosion resistance of casting sample using gold coping was lower than that of casting sample using gold/plastic coping, and a severe corrosion pattern was observed at the abutment-casting gold alloy interface by the SEM.
Alloys* ; Corrosion* ; Gold Alloys

After clinical adjustment of dental casting restoration, re-polishing procedure is recommanded because the smooth gold sureface is lost. But there is the possibility to get more loose contact than that intended by loss of gold alloy according to the kinds of polishing materials and polishing time. Therefore in this study I polished type II gold alloy with 390gm force, 20,000rpm speed, and 8 kinds of gold alloy polishing materials, fabricated by 4 companies and then measured the amount of loss of gold alloy with Surfcorder SEF30D and observed alloy surfaces polished by 3 brown rubber points with SEM. The amount of loss of gold alloys polished with 8 kinds of polishing materials and the degree of smoothness of gold alloys according to polishing time and polishing materials were compared. The following results were obtained : 1. When the amount of loss of gold alloys polished with 3 kinds of brown rubber point was compared, Alphalex brown point had the most amount of alloy loss, followed in decreasing order by Shofu brown point and Eveflex brown point. There was statistically significant difference in the amount of alloy loss according to polishing materials. 2. When the amount of loss of gold alloys polished with 5 kinds of green rubber point was compared, Shofu green point had the most amount of alloy loss, followed in decreasing order by Alphaflex green point, Dedeco green clasp polisher, and Eveflex green point. There was statistically significant difference in the amount of alloy loss according to polishing materials except Alphaflex green point and Dedeco green clasp polisher. 3. When the amount of loss of gold alloys polished with all kinds of rubber point was compared, there was no significant difference in Eveflex brown point, Alphaflex green point, and Dedeco green claps polisher. 4. When average amount of alloy loss per 1 revolution by polishing materials was compared, Alphalex brown point had the greatest value as 0.329micrometer and Shofu supergreen point had the lowest value as 0.022micrometer. 5. When the degree of sureface smoothness of gold alloy polished with 3 kinds of brown rubber point was compared, in Alphalex brown point surface roughness was completely lost after 20 seconds polishing time, in Shofu brown point 30 seconds, in Eveflex brown point 40 seconds. But in every gold alloys fine scratch formed by rubber points was observed. Based on the results of this study, as rubber polishing materials used in polishing of dental casting restoration after clinical adjustment influenced on the tightness of occlusal or proximal contact, we should make dental casting restoration with minimum error through careful laboratory procedure and form very smooth surface of restoration with tripoli and rouge after use of silicone polishing materials.
Alloys* ; Gold Alloys ; Rubber* ; Silicones

After clinical adjustment of dental casting restoration, re-polishing procedure is recommanded because the smooth gold sureface is lost. But there is the possibility to get more loose contact than that intended by loss of gold alloy according to the kinds of polishing materials and polishing time. Therefore in this study I polished type II gold alloy with 390gm force, 20,000rpm speed, and 8 kinds of gold alloy polishing materials, fabricated by 4 companies and then measured the amount of loss of gold alloy with Surfcorder SEF30D and observed alloy surfaces polished by 3 brown rubber points with SEM. The amount of loss of gold alloys polished with 8 kinds of polishing materials and the degree of smoothness of gold alloys according to polishing time and polishing materials were compared. The following results were obtained : 1. When the amount of loss of gold alloys polished with 3 kinds of brown rubber point was compared, Alphalex brown point had the most amount of alloy loss, followed in decreasing order by Shofu brown point and Eveflex brown point. There was statistically significant difference in the amount of alloy loss according to polishing materials. 2. When the amount of loss of gold alloys polished with 5 kinds of green rubber point was compared, Shofu green point had the most amount of alloy loss, followed in decreasing order by Alphaflex green point, Dedeco green clasp polisher, and Eveflex green point. There was statistically significant difference in the amount of alloy loss according to polishing materials except Alphaflex green point and Dedeco green clasp polisher. 3. When the amount of loss of gold alloys polished with all kinds of rubber point was compared, there was no significant difference in Eveflex brown point, Alphaflex green point, and Dedeco green claps polisher. 4. When average amount of alloy loss per 1 revolution by polishing materials was compared, Alphalex brown point had the greatest value as 0.329micrometer and Shofu supergreen point had the lowest value as 0.022micrometer. 5. When the degree of sureface smoothness of gold alloy polished with 3 kinds of brown rubber point was compared, in Alphalex brown point surface roughness was completely lost after 20 seconds polishing time, in Shofu brown point 30 seconds, in Eveflex brown point 40 seconds. But in every gold alloys fine scratch formed by rubber points was observed. Based on the results of this study, as rubber polishing materials used in polishing of dental casting restoration after clinical adjustment influenced on the tightness of occlusal or proximal contact, we should make dental casting restoration with minimum error through careful laboratory procedure and form very smooth surface of restoration with tripoli and rouge after use of silicone polishing materials.
Alloys* ; Gold Alloys ; Rubber* ; Silicones

BACKGROUND: The oral mucosa is constantly exposed to several irritants and allergens including dental materials, but the role of contact allergy in oral disease is obscure. OBJECTIVE: To analyze positive patch test results in patients with oral diseases and evaluate the clinical relevance of oral diseases with contact allergy to dental materials. METHODS: We retrospectively analyzed patch test results with dental screening series in 44 patients with oral disease from 2004~2011. RESULTS: Oral diseases included oral lichen planus (54.5%), cheilitis (27.3%), burning mouth syndrome (9.1%), and others (9.1%). Thirty-one of 44 patients (70.5%) had positive reactions to one or more allergens. The most commonly detected allergens were gold sodium thiosulfate (25.0%) and nickel sulfate (25.0%), followed by potassium dichromate (22.7%), cobalt (15.9%), palladium (6.8%), mercury (4.5%), copper (4.5%), and methylhydroquinone (4.5%). Six of 24 patients with oral lichen planus had a symptom in areas adjacent to dental materials and positive patch test reactions to allergens contained in the suspected dental materials. CONCLUSION: Patch tests with dental screening series are worth considering for oral diseases, especially for oral lichen planus.
Allergens ; Burning Mouth Syndrome ; Cheilitis ; Cobalt ; Copper ; Dental Materials ; Gold Sodium Thiosulfate ; Humans ; Hypersensitivity ; Irritants ; Lichen Planus, Oral ; Mass Screening* ; Mouth Mucosa ; Nickel ; Palladium ; Patch Tests* ; Potassium Dichromate ; Retrospective Studies