32 research outputs found

    Probe Functionalization With A Rhop-3 Antibody: Toward A Rhop-3 Antigen Immunosensor For Detection of Malaria

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    The antibody specific for the malaria protein, Rhop-3, and FL-Rhop-3, were immobilized on the surface of a gold electrode modified with cysteamine. Colloidal gold was used to enhance the detection signal for Rhop-3 antigens. The Rhop-3 antibody was also immobilized on gold electrodes preactivated with dithiobis(succinimidyl proprionate) (DSP). Immobilization was performed at room temperature and at 37 °C. Cyclic voltammetry (CV) was used to monitor the interaction between the immobilized antibody and its cognate antigen in solution, using ferricyanide, K3Fe(CN)6, as reporting electroactive probe. Tests indicate recognition of Rhop-3 protein by the immobilized antibody. Antigen recognition was enhanced by incubation at 37 °C compared with room-temperature incubation. Our results suggest that an immunosensor can be developed and optimized to aid detection of Rhop-3 antigens in samples from malaria patients. As far as we are aware, this is the first amperometric immunosensor targeting Rhop-3 antigen as a malaria biomarker

    Cholesterol Levels and Activity of Membrane Bound Proteins: Characterization by Thermal and Electrochemical Methods

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    The long-term goal of this investigation is to study the effects of increased cholesterol levels on the molecular activity of membrane-bound enzymes such as nitric oxide synthase, that are critical in the functioning of the cardiovascular system. In this particular investigation, we used differential scanning calorimetry (DSC) and dielectric thermal analysis (DETA) to study the effect of added cholesterol on melting/recrystallization and dielectric behavior, respectively, of phosphatidylcholine (PC) bilayered thin films. We also used electrochemical methods to investigate the effect of added cholesterol on the redox behavior of the oxygenase domain of nitric oxide synthase as a probe embedded in the PC films. The results show that added cholesterol in the PC films seems to depress the molecular dynamics as indicated by lowered current responses in the presence of cholesterol as well as a slight increase of the transition temperature in the overall two-phase regime behavior observed in PC–cholesterol films. These results are rationalized in the context of the general DSC and DETA behaviors of the PC–chol films

    Probe Functionalization With A Rhop-3 Antibody: Toward A Rhop-3 Antigen Immunosensor For Detection of Malaria

    No full text
    The antibody specific for the malaria protein, Rhop-3, and FL-Rhop-3, were immobilized on the surface of a gold electrode modified with cysteamine. Colloidal gold was used to enhance the detection signal for Rhop-3 antigens. The Rhop-3 antibody was also immobilized on gold electrodes preactivated with dithiobis(succinimidyl proprionate) (DSP). Immobilization was performed at room temperature and at 37 °C. Cyclic voltammetry (CV) was used to monitor the interaction between the immobilized antibody and its cognate antigen in solution, using ferricyanide, K3Fe(CN)6, as reporting electroactive probe. Tests indicate recognition of Rhop-3 protein by the immobilized antibody. Antigen recognition was enhanced by incubation at 37 °C compared with room-temperature incubation. Our results suggest that an immunosensor can be developed and optimized to aid detection of Rhop-3 antigens in samples from malaria patients. As far as we are aware, this is the first amperometric immunosensor targeting Rhop-3 antigen as a malaria biomarker

    Thermal Analysis of Model Bio-Polymers: Poly-L-Lactic Acid and Shedded Snake Skins

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    Biological polymers, or biopolymers, are of great interest in medical research. Compatibility of materials placed in the human body is important because of the known rejection of many thermoplastics. However, polypropylene, a classic thermoplastic, used in hernia repairs is typically not rejected. Researchers are constantly seeking biopolymers which are accepted by the human body. One very popular polymer that is being studied in our laboratories is poly-L-lactic acid. Poly-L-lactic Acid (PLLA) is an optically active, biocompatible and biodegradable polymer that has been widely investigated as an artificial cell scaffold material. In its most crystalline form, PLLA is highly anisotropic and is one of the most piezoelectric polymers known. Conversely, amorphous PLLA exhibits little, if any, piezoelectric behavior. Compression molded PLLA films can be endowed with varying amounts of crystalline character and piezoelectricity by uniaxially stretching the polymer in a hot air bath. Understanding the precise crystalline architecture of PLLA that results from tensile drawing is important for constructing cell scaffolds that have highly tailored biodegradation and cell guiding properties. In our work here, we investigate the changes in the thermal properties of PLLA at draw ratios between 1 and 5.5 using differential scanning calorimetry (DSC). The crystallinity of the compression molded undrawn starting material and drawn films are characterized using wide angle X-ray diffraction analysis. Our DSC results show an increase in percent crystallinity with increasing draw up to a draw ratio of 4.0. At greater draw ratios, there is a decrease in the crystalline character exhibited by PLLA. There is a growing interest in employing the transdermal pathway for administration of drugs. In order to develop knowledge of the drug transport properties or the effects of sun radiation on human skin, one needs a practical human skin model. We propose that shedded snake skins are biological polymers which fit the need and are readily available. We have developed in our laboratories a correlation in the thermal properties by TG, DTG and DTA between the human and shedded snake skins. Based on these correlations, we are studying the effects of chemicals and radiation on shedded snake skin as predictive model membranes for human skin behavior. The present study concerns the evaluation of various shedded snake skins by Thermal Mechanical Analysis (TMA). The low temperature TMA will be used to verify the effectiveness of sun screen creams and lotions

    Characterization of the raw essential oil eugenol extracted from Syzygium aromaticum L.

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    Eugenol is the main volatile compound extracted oil from clove bud, Syzygium aromaticum L., and used in traditional medicine, as a bactericide, fungicide, anesthetic, and others. Its extraction was performed using hydrodistillation which is the most common extraction technique. Its components and thermal behavior were evaluated using gas chromatography (GC) and differential scanning calorimetry (DSC), which provide a better characterization of these natural compounds. This extracted product was compared to the standard eugenol results. The GC results suggested similar to 90% eugenol was found in the total extracted oil, and some of its boiling characteristics were 270.1 A degrees C for peak temperature and 244.1 J g(-1) for the enthalpy variation

    Thermal Analysis of Model Bio-Polymers: Poly-L-Lactic Acid and Shedded Snake Skins

    No full text
    Biological polymers, or biopolymers, are of great interest in medical research. Compatibility of materials placed in the human body is important because of the known rejection of many thermoplastics. However, polypropylene, a classic thermoplastic, used in hernia repairs is typically not rejected. Researchers are constantly seeking biopolymers which are accepted by the human body. One very popular polymer that is being studied in our laboratories is poly-L-lactic acid. Poly-L-lactic Acid (PLLA) is an optically active, biocompatible and biodegradable polymer that has been widely investigated as an artificial cell scaffold material. In its most crystalline form, PLLA is highly anisotropic and is one of the most piezoelectric polymers known. Conversely, amorphous PLLA exhibits little, if any, piezoelectric behavior. Compression molded PLLA films can be endowed with varying amounts of crystalline character and piezoelectricity by uniaxially stretching the polymer in a hot air bath. Understanding the precise crystalline architecture of PLLA that results from tensile drawing is important for constructing cell scaffolds that have highly tailored biodegradation and cell guiding properties. In our work here, we investigate the changes in the thermal properties of PLLA at draw ratios between 1 and 5.5 using differential scanning calorimetry (DSC). The crystallinity of the compression molded undrawn starting material and drawn films are characterized using wide angle X-ray diffraction analysis. Our DSC results show an increase in percent crystallinity with increasing draw up to a draw ratio of 4.0. At greater draw ratios, there is a decrease in the crystalline character exhibited by PLLA. There is a growing interest in employing the transdermal pathway for administration of drugs. In order to develop knowledge of the drug transport properties or the effects of sun radiation on human skin, one needs a practical human skin model. We propose that shedded snake skins are biological polymers which fit the need and are readily available. We have developed in our laboratories a correlation in the thermal properties by TG, DTG and DTA between the human and shedded snake skins. Based on these correlations, we are studying the effects of chemicals and radiation on shedded snake skin as predictive model membranes for human skin behavior. The present study concerns the evaluation of various shedded snake skins by Thermal Mechanical Analysis (TMA). The low temperature TMA will be used to verify the effectiveness of sun screen creams and lotions
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