Sh. Nadzirah

Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7

Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO2) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl) triethoxysilane (APTES) to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO2 nanoparticles while maintaining the sensing system’s physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10-13M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%), displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.

Rapid and sensitive strategy for Human Papillomavirus (HPV) detection using a gene-based DNA nanobiosensor

Human Papillomavirus (HPV) is the most common sexually transmitted virus that infected to human. The most common high-risk HPV are 16 and 18. Most 70% of cervical cancers (CC) are due to infection by these genotypes. A rapid and sensitive strategy for the detection of Human Papillomavirus (HPV) was proposed by integrating simple DNA extraction with gene-based DNA nanobiosensor. DNA nanochip is a powerful tool allowing detection HPV target molecules present in a sample. The efficiency of DNA nanochip depends mainly on the sequence of the capture probes and the way they are attached to the support. The coupling procedure must be quick, covalent, and reproducible. The fabrication, immobilization and hybridization processes were characterized with current voltage (I-V) characterization (KEITHLEY, 6487). This strategy presented a simple, rapid and sensitive platform for HPV detection and would become a powerful tool for pathogenic microorganisms screening in clinical diagnosis.

Annealing effects on titanium dioxide films by Sol-Gel spin coating method

TiO2 thin films were deposited on silicon dioxide substrates using a sol-gel method. The surface morphologies, structural and electrical properties at different annealing temperatures were studied using atomic force microscopy (AFM), X-ray diffraction (XRD) and Kiethley 6485 pico-ammeter. The XRD pattern displayed the presence of anatase and rutile structures even at low temperature while AFM displayed that the annealing temperature affects the particle size. Current-voltage (I-V) characteristic revealed that the conductivity decreased as the annealing temperature varied from 300 to 900oC.

Effects of annealing temperature on current-voltage characteristics of TiO 2 thin film by sol-gel process on silicon substrate for biosensor application

TiO2 thin film was deposited on a silicon dioxide substrate using a sol-gel method and the film was annealed at 300, 500 and 700°C. Aluminum interdigitated electrodes were fabricated on the deposited TiO2 thin film via simple lithography method. The influence of thermal annealing towards the morphological and electrical properties were studied. X-ray diffraction (XRD) shows that crystalline rutile structure growth at very low temperature whereas field emission electron microscopy (FESEM) exhibits nanoparticles with an average 21 mm in size. The current flows between the fabricated interdigitated electrodes were extremely small at -5 to 5 V applied which were decreased as the annealing temperature increases with average barrier height was 0.8 eV.

Integrated titanium dioxide (TiO2) nanoparticles on interdigitated device electrodes (IDEs) for pH analysis

Titanium dioxide (TiO2) nanoparticles based Interdigitated Device Electrodes (IDEs) Nanobiosensor device was developed for intracellular biochemical detection. Fabrication and characterization of pH sensors using IDE nanocoated with TiO2 was studied in this paper. In this paper, a preliminary assessment of this intracellular sensor with electrical measurement under different pH levels. 3-aminopropyltriethoxysilane (APTES) was used to enhance the sensitivity of titanium dioxide layer as well as able to provide surface modification by undergoing protonation and deprotonation process. Different types of pH solution provide different resistivity and conductivity towards the surface. Base solution has the higher current compared to an acid solution. Amine and oxide functionalized TiO2 based IDE exhibit pH-dependent could be understood in terms of the change in surface charge during protonation and deprotonation. The simple fabrication process, high sensitivity, and fast response of the TiO2 based IDEs facilita...

Surface morphology of titanium dioxide (TiO2) nanoparticles on aluminum interdigitated device electrodes (IDEs)

Titanium dioxide (TiO2) nanoparticles based Interdigitated Device Electrodes (IDEs) Nanobiosensor device was developed for intracellular biochemical detection. Fabrication and characterization of Scanning Electron Microscopy (SEM) using IDE nanocoated with TiO2 was studied in this paper. SEM analysis was carried out at 10 kV acceleration volatege and a 9.8 mA emission current to compare IDE with and without TiO2 on the surface area. The simple fabrication process, high sensitivity, and fast response of the TiO2 based IDEs facilitate their applications in a wide range of areas. The small size of semiconductor TiO2 based IDE for sensitive, label-free, real time detection of a wide range of biological species could be explored in vivo diagnostics and array-based screening.

Titanium dioxide nanoparticles for pH sensor

TiO2 nanoparticles-based interdigitated electrode is tested as pH electrodes and measured quantitatively. TiO2 nanoparticle was synthesized via sol-gel method while interdigitated electrodes were fabricated by conventional photolithography method. Deposition of TiO2 solution on the fabricated electrodes forms a sensor that promising for development of TiO2 nanoparticles based biosensors. The extremely small amount of current measurement of this device towards hydrogen and hydroxide ions was measured by Keithley 6487 picoammeter.

Rapid and sensitive E-Coli DNA detection by titanium dioxide nanoparticles

Escherichia Coli (E. coli) issue has been discovered since 1985 according to its ability to cause large outbreaks of gastrointestinal illness especially O157:H7 type. A new and simple method for label free, rapid and inexpensive of titanium dioxide (TiO2) nanoparticles biosensor based transducer on E. Coli DNA has been fabricated via sol-gel spin-coating technique. A simple quantitative approach was used to detect the existence of E. coli on the fabricated device. Extremely small steady current (picoammeters) were achieved, which indicates that this device can possibly go to very high sensitivities sensor towards DNA detection. A simple electrical signal of current-to-voltage (I-V) which provides small current was used to verify all the measurement of the device. (3-Aminopropyl)triethoxysilane (APTES) was functionalized through silanization process to modify the surface of TiO2 nanoparticles through the covalent bond between hydroxyl groups of TiO2 and organofunctional alkoxysilane group from APTES. The probe DNA was successfully immobilized and performed for hybridization with complementary DNA when the current is 3.5 E-10 ≤ I ≤ 4.5 E-10 A. The microchip showed reliable capture of E. coli in deionized water with an efficiency of 33.6% ± 5% at concentration of 1.0 μM.

Effect of different concentration of HPV DNA probe immobilization for cervical cancer detection based IDE biosensor

This paper principally delineates to the detection process of Human Papillomavirus (HPV) DNA test. HPV is an extremely common virus infection that infected to human by the progressions cell in the cervix cell. The types of HPV that give a most exceedingly awful infected with cervical cancer is 16 and 18 other than 31 and 45. The HPV DNA probe is immobilized with a different concentration to stabilize the sensitivity. A technique of rapid and sensitive for the HPV identification was proposed by coordinating basic DNA extraction with a quality of DNA. The extraction of the quality of DNA will make a proficiency of the discovery procedure. It will rely on the sequence of the capture probes and the way to support their attached. The fabrication, surface modification, immobilization and hybridization procedures are described by current-voltage (I-V) estimation by utilizing KEITHLEY 6487. This procedure will play out a decent affectability and selectivity of HPV discovery.

Comparison of different methods for extraction and purification of human Papillomavirus (HPV) DNA from serum samples

The affectability and unwavering quality of PCR for indicative and research purposes require effective fair systems of extraction and sanitization of nucleic acids. One of the real impediments of PCR-based tests is the hindrance of the enhancement procedure by substances exhibit in clinical examples. This examination considers distinctive techniques for extraction and cleaning of viral DNA from serum tests in view of recuperation productivity as far as yield of DNA and rate recouped immaculateness of removed DNA, and rate of restraint. The best extraction strategies were the phenol/chloroform strategy and the silica gel extraction methodology for serum tests, individually. Considering DNA immaculateness, extraction technique by utilizing the phenol/chloroform strategy delivered the most tasteful results in serum tests contrasted with the silica gel, separately. The nearness of inhibitors was overcome by all DNA extraction strategies in serum tests, as confirm by semiquantitative PCR enhancement.