Micro-interdigitated electrodes genosensor based on Au-deposited nanoparticles for early detection of cervical cancer.

Genosensor-based electrodes mediated with nanoparticles (NPs) have tremendously developed in medical diagnosis. Herein, we report a facile, rapid, low cost and highly sensitive biosensing strategy for early detection of HPV 18 using gold-nanoparticles (AuNPs) deposited on micro-IDEs. This study represents surface charge transduction of micro-interdigitated electrodes (micro-IDE) alumina insulated with silica, independent and mini genosensor modified with colloidal gold NPs (AuNPs), and determination of gene hybridization for early detection of cervical cancer. The surface of AuNPs deposited micro-IDE functionalized with optimized 3-aminopropyl-triethoxysilane (APTES) followed by hybridization with deoxyribonucleic acid (DNA) virus to develop DNA genosensor. The results of ssDNA hybridization with the ssDNA target of human papillomavirus (HPV) 18 have affirmed that micro-IDE functionalized with colloidal AuNPs resulted in the lowest detection at 0.529 aM. Based on coefficient regression, micro-IDE functionalized with AuNPs produces better results in the sensitivity test (R2 = 0.99793) than unfunctionalized micro-IDE.

Natural Baicalein-Rich Fraction as Radiosensitizer in Combination with Bismuth Oxide Nanoparticles and Cisplatin for Clinical Radiotherapy.

Purpose: Chemotherapy has been used in conjunction with radiation therapy to improve the treatment outcomes of cancers. Cisplatin (Cis) is a standard treatment that has been used as a chemotherapeutic drug in medical settings. However, the possibility of complications constrains the treatment due to the exposure of healthy organs to unnecessary radiation and the drugs' toxicities. As a result, researchers have been looking for non-toxic chemotherapeutic agents which can be used as radiosensitizers, possibly produced from natural derivatives and nano sized materials. Methods: BRF, Cis, and BiONPs were irradiated individually and in combinations with 6 MV of photon beam and 6 MeV of electron beams with 0 to 10 Gy radiation doses on MCF-7, MDA-MB-231, and NIH/3T3 cell lines. Then, the experimental sensitization enhancement ratios (SER) of each treatment obtained were compared to the theoretical dose enhancement factor (DEF). The interactions within the BRF-BiONPs (BB) and BRF-Cis-BiONPs (BCB) combinations were also estimated using the Combination Index (CI). Results: BRF induced radiosensitization in all cells under 6 MV photon beam (SER of 1.06 to 1.35), and MDA-MB-231 cells only under 6 MeV electron beam (SER = 1.20). The highest SER values for BiONPs and Cis were obtained from MCF-7 cells under a 6 MeV electron beam (SER of 1.50 and 2.24, respectively). The theoretical DEFs were generally lower than the experimental SERs. Based on the SER and CI relationships, it was estimated that BB and BCB therapy methods interacted in either a synergistic or additive manner. Conclusion: The BRF is found to induce relatively less radiosensitization effects compared to the BiONPs and Cis. The BB and BCB combinations have shown better effects with potential for becoming competently suitable radiosensitizers in breast cancer therapies.

Radiosensitization effects by bismuth oxide nanorods of different sizes in megavoltage external beam radiotherapy.

BACKGROUND: Nanotechnology application has successfully reached numerous scientific breakthroughs including in radiotherapy. However, the clinical application of nanoparticles requires more diligent research primarily on the crucial parameters such as nanoparticle sizes. This study is aimed to investigate the influence of bismuth oxide nanorod (Bi2O3-NR) sizes on radiosensitization effects on MCF-7 and HeLa cell lines for megavoltage photon and electron beam radiotherapy. MATERIALS AND METHODS: MCF-7 and HeLa cells were treated with and without 0.5 µMol/L of Bi2O3-NR of varying sizes (60, 70, 80, and 90 nm). The samples, including the control groups, were exposed to different radiation doses (0-10 Gy), using photon (6 MV and 10 MV), and electron beam (6 MeV and 12 MeV) radiotherapy. Clonogenic assay was performed, and sensitization enhancement ratio (SER) was determined from linear quadratic based cell survival curves. RESULTS: The results depicted that 60 nm Bi2O3-NR yields the most excellent SER followed by 70 nm Bi2O3-NR. Meanwhile, the 80 and 90 nm Bi2O3-NR showed an insignificant difference between treated and untreated cell groups. This study also found that MCF-7 was subjected to more cell death compared to HeLa. CONCLUSION: 60 nm Bi2O3-NR was the optimal Bi2O3-NR size to induce radiosensitization effects for megavoltage external beam radiotherapy. The SER in photon beam radiotherapy marked the highest compared to electron beam radiotherapy due to decreased primary radiation energy from multiple radiation interaction and higher Compton scattering.

Recent progress of conductive 3D-printed electrodes based upon polymers/carbon nanomaterials using a fused deposition modelling (FDM) method as emerging electrochemical sensing devices.

3D-printing or additive manufacturing is presently an emerging technology in the fourth industrial revolution that promises to reshape traditional manufacturing processes. The electrochemistry field can undoubtedly take advantage of this technology to fabricate electrodes to create a new generation of electrode sensor devices that could replace conventionally manufactured electrodes; glassy carbon, screen-printed carbon and carbon composite electrodes. In the electrochemistry research area, studies to date show that there is a demand for electrically 3D printable conductive polymer/carbon nanomaterial filaments where these materials can be printed out through an extrusion process based upon the fused deposition modelling (FDM) method. FDM could be used to manufacture novel electrochemical 3D printed electrode sensing devices for electrochemical sensor and biosensor applications. This is due to the FDM method being the most affordable 3D printing technique since conductive and non-conductive thermoplastic filaments are commercially available. Therefore, in this minireview, we focus on only the most outstanding studies that have been published since 2018. We believe this to be a highly-valuable research area to the scientific community, both in academia and industry, to enable novel ideas, materials, designs and methods relating to electroanalytical sensing devices to be generated. This approach has the potential to create a new generation of electrochemical sensing devices based upon additive manufacturing. This minireview also provides insight into how the research community could improve the electrochemical performance of 3D-printed electrodes to significantly increase the sensitivity of the 3D-printed electrodes as electrode sensing devices.

Formation of grassy TiO2 nanotube thin film by anodisation in peroxide electrolyte for Cr(VI) removal under ultraviolet radiation.

Arrays of TiO2 nanotubes (TiO2 NTs) with grassy surfaces were observed on titanium foil anodised at 60 V in fluorinated ethylene glycol (EG) with added hydrogen peroxide (H2O2). The grassy surface was generated by the chemical etching and dissolution of the surface of the TiO2 NTs walls, which was accelerated by the temperature increase on the addition of H2O2 . Upon annealing at 600 °C, the grassy part of the TiO2 NTs was found to consist of mostly anatase TiO2 whereas the bottom part of the anodic oxide comprised a mixture of anatase and rutile TiO2. The TiO2 NTs were then used to reduce hexavalent chromium (Cr(VI)) under ultraviolet radiation. They exhibited a rather efficient photocatalytic effect, with 100% removal of Cr(VI) after 30 min of irradiation. The fast removal of Cr(VI) was due to the anatase dominance at the grassy part of the TiO2 NTs as well as the higher surface area the structure may have. This work provides a novel insight into the photocatalytic reduction of Cr(VI) on grassy anatase TiO2 NTs.

Sunlight activated anodic freestanding ZrO2 nanotube arrays for Cr(VI) photoreduction.

Visible-light-active freestanding zirconia (ZrO2) nanotube (FSZNT) arrays were fabricated by a facile electrochemical anodization method in fluoride containing ethylene glycol electrolyte added to it was 1 vol% of potassium carbonate (K2CO3) at 60 V for 1 h. Poor adhesion at the metal∣oxide interface was induced by K2CO3 leading to the formation of FSZNT flakes. The effect of the crystal structures of the FSZNTs e.g., amorphous, amorphous/tetragonal, and tetragonal/monoclinic was investigated towards the photocatalytic reduction of 10 ppm hexavalent chromium, Cr(VI) at pH 2 under sunlight. The results demonstrate the amorphous FSZNTs exhibited the highest Cr(VI) removal efficiency than the crystalline FSZNTs (95% versus 33% after 5 h). The high photocatalytic activity of the amorphous FSZNTs can be attributed to enhanced Cr(VI) adsorption, high visible light absorption, and better charge carrier separation. The low photocatalytic activity of the crystalline FSZNTs annealed at 500 °C was mainly attributed to poor Cr(VI) adsorption, low visible light absorption, and less photoactive monoclinic-ZrO2.

Formation of two-dimensional ZnO nanosheets by rapid thermal oxidation in oxygenated environment.

Crystalline 2-D (dimensional) ZnO nanosheets were formed by rapid thermal oxidation of etched Zn foil in oxygen at 300 degrees C and 400 degrees C. Short oxidation time was varied from 10, 20 and 30 min. The morphologies and optical properties of the ZnO nanosheets evolved with the oxidation temperature and time. At 300 degrees C, ZnO nanosheets with thickness ranging from 32 nm to 80 nm were obtained while at 400 degrees C, the thickness of the nanosheets increased from 88 nm to approximately 200 nm after 10 and 30 min of oxidation, respectively. The surface roughness of the ZnO nanosheets and grain size increased with oxidation time and temperature. Photoluminescence of the oxidized samples shows ultraviolet (UV) and visible emissions indicating good crystallinity of ZnO which was further confirmed by high-resolution transmission electron microscope observation of ZnO wurtzite interplanar spacing. Photocatalytic activity of ZnO was also investigated by using degradation of methyl orange (MO) and all the samples exhibit photocatalytic activity. The sample oxidized at 400 degrees C for 10 min show better MO degradation after 2 h of exposure due to higher surface area and better crystallinity of the ZnO nanosheets obtained.

Production of recombinant Entamoeba histolytica pyruvate phosphate dikinase and its application in a lateral flow dipstick test for amoebic liver abscess.

BACKGROUND: Amoebic liver abscess (ALA) is the most common clinical manifestation of extraintestinal amoebiasis especially in developing countries, causing up to 100 000 fatal cases annually. Accurate and early diagnosis is important to prevent the disease complications, however its diagnosis still poses many challenges due to the limitations of the available detection tools. Pyruvate phosphate dikinase (PPDK), an excretory-secretory protein of E. histolytica, has been reported as a potential diagnostic marker for ALA, hence it may be exploited in the development of a new test for ALA. METHODS: Recombinant PPDK (rPPDK) was expressed, purified and evaluated by Western blot. In parallel, recombinant galactose-and-N-acetyl-D-galactosamine inhibitable lectin (Gal/GalNAc lectin) was produced and tested similarly. The protein identity was confirmed by analysis using MALDI-TOF/TOF. A lateral flow dipstick (LFD) test using rPPDK was subsequently developed (rPPDK-LFD) and evaluated for serodiagnosis of ALA. RESULTS: rPPDK was expressed as soluble protein after 4 hours of induction with 1 mM isopropyl ß-D-1-thiogalactopyranoside (IPTG) at 30°C. Purification using nickel-nitrilotriacetic acid (Ni-NTA) resin yielded 1.5 mg of rPPDK from 1 L of culture with estimated molecular mass of 98 kDa on SDS-PAGE. Western blots using sera from patients with ALA, healthy individuals and other diseases probed with anti-human IgG4-HRP showed the highest sensitivity (93.3%) and specificity (100%); as compared to blots using IgG and IgG1 as secondary antibodies. Moreover, rPPDK showed better specificity when compared to rGal/GalNAc lectin. In the development of the LFD test, the optimum amount of rPPDK was 0.625 µg per dipstick and the optimum working concentration of colloidal gold conjugated anti-human IgG4 was optical density (OD) 5 (1.7 µg of anti-human IgG4). Evaluation of rPPDK-LFD using ALA patients and controls serum samples showed 87% diagnostic sensitivity and 100% specificity. CONCLUSION: The developed rPPDK-LFD showed good potential for rapid diagnosis of ALA, and merit further multicentre validation using larger number of serum samples.

Gold nanoparticles deposited on linker-free silicon substrate and embedded in aluminum Schottky contact.

Given the enormous importance of Au nanoparticles (NPs) deposition on Si substrates as the precursor for various applications, we present an alternative approach to deposit Au NPs on linker-free n- and p-type Si substrates. It is demonstrated that, all conditions being similar, there is a significant difference between densities of the deposited NPs on both substrates. The Zeta-potential and polarity of charges surrounding the hydroxylamine reduced seeded growth Au NPs, are determined by a Zetasizer. To investigate the surface properties of Si substrates, contact angle measurement is performed. Field-emission scanning electron microscope is then utilized to distinguish the NPs density on the substrates. Finally, Al/Si Schottky barrier diodes with embedded Au NPs are fabricated, and their structural and electrical characteristics are further evaluated using an energy-filtered transmission electron microscope and current-voltage measurements, respectively. The results reveal that the density of NPs is significantly higher on n-type Si substrate and consequently has more pronounced effects on the electrical characteristics of the diode. It is concluded that protonation of Si-OH group on Si surface in low pH is responsible for the immobilization of Au NPs, which eventually contributes to the lowering of barrier height and enhances the electrical characteristics.

Structural and morphology of ZnO nanorods synthesized using ZnO seeded growth hydrothermal method and its properties as UV sensing.

In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ZnO seeds was 400°C. The nanorod dimensions depended on the hydrothermal reaction parameters. The optimum hydrothermal reaction parameters to produce blunt tip-like nanorods (770 nm long and 80 nm in top diameter) were 0.1 M zinc nitrate, pH 7, and 4 h of growth duration. Phase analysis studies showed that all ZnO nanorods exhibited a strong (002) peak. Thus, the ZnO nanorods grew in a c-axis preferred orientation. A strong ultraviolet (UV) emission peak was observed for ZnO nanorods grown under optimized parameters with a low, deep-level emission peak, which indicated high optical property and crystallinity of the nanorods. The produced ZnO nanorods were also tested for their UV-sensing properties. All samples responded to UV light but with different sensing characteristics. Such different responses could be attributed to the high surface-to-volume ratio of the nanorods that correlated with the final ZnO nanorods morphology formed at different synthesis parameters. The sample grown using optimum synthesis parameters showed the highest responsivity of 0.024 A/W for UV light at 375 nm under a 3 V bias.

The effects of size and synthesis methods of gold nanoparticle-conjugated MαHIgG4 for use in an immunochromatographic strip test to detect brugian filariasis.

This study describes the properties of colloidal gold nanoparticles (AuNPs) with sizes of 20, 30 and 40 nm, which were synthesized using citrate reduction or seeding-growth methods. Likewise, the conjugation of these AuNPs to mouse anti-human IgG(4) (MαHIgG(4)) was evaluated for an immunochromatographic (ICG) strip test to detect brugian filariasis. The morphology of the AuNPs was studied based on the degree of ellipticity (G) of the transmission electron microscopy images. The AuNPs produced using the seeding-growth method showed lower ellipticity (G ≤ 1.11) as compared with the AuNPs synthesized using the citrate reduction method (G ≤ 1.18). Zetasizer analysis showed that the AuNPs that were synthesized using the seeding-growth method were almost monodispersed with a lower polydispersity index (PDI; PDI≤0.079), as compared with the AuNPs synthesized using the citrate reduction method (PDI≤0.177). UV-visible spectroscopic analysis showed a red-shift of the absorbance spectra after the reaction with MαHIgG(4), which indicated that the AuNPs were successfully conjugated. The optimum concentration of the BmR1 recombinant antigen that was immobilized on the surface of the ICG strip on the test line was 1.0 mg ml(-1). When used with the ICG test strip assay and brugian filariasis serum samples, the conjugated AuNPs-MαHIgG(4) synthesized using the seeding-growth method had faster detection times, as compared with the AuNPs synthesized using the citrate reduction method. The 30 nm AuNPs-MαHIgG(4), with an optical density of 4 from the seeding-growth method, demonstrated the best performance for labelling ICG strips because it displayed the best sensitivity and the highest specificity when tested with serum samples from brugian filariasis patients and controls.

Direct formation of gold nanoparticles on substrates using a novel ZnO sacrificial templated-growth hydrothermal approach and their properties in organic memory device.

This study describes a novel fabrication technique to grow gold nanoparticles (AuNPs) directly on seeded ZnO sacrificial template/polymethylsilsesquioxanes (PMSSQ)/Si using low-temperature hydrothermal reaction at 80°C for 4 h. The effect of non-annealing and various annealing temperatures, 200°C, 300°C, and 400°C, of the ZnO-seeded template on AuNP size and distribution was systematically studied. Another PMMSQ layer was spin-coated on AuNPs to study the memory properties of organic insulator-embedded AuNPs. Well-distributed and controllable AuNP sizes were successfully grown directly on the substrate, as observed using a field emission scanning electron microscope followed by an elemental analysis study. A phase analysis study confirmed that the ZnO sacrificial template was eliminated during the hydrothermal reaction. The AuNP formation mechanism using this hydrothermal reaction approach was proposed. In this study, the AuNPs were charge-trapped sites and showed excellent memory effects when embedded in PMSSQ. Optimum memory properties of PMMSQ-embedded AuNPs were obtained for AuNPs synthesized on a seeded ZnO template annealed at 300°C, with 54 electrons trapped per AuNP and excellent current-voltage response between an erased and programmed device.

Overview of the main methods used to combine proteins with nanosystems: absorption, bioconjugation, and encapsulation.

The latest development of protein engineering allows the production of proteins having desired properties and large potential markets, but the clinical advances of therapeutical proteins are still limited by their fragility. Nanotechnology could provide optimal vectors able to protect from degradation therapeutical biomolecules such as proteins, enzymes or specific polypeptides. On the other hand, some proteins can be also used as active ligands to help nanoparticles loaded with chemotherapeutic or other drugs to reach particular sites in the body. The aim of this review is to provide an overall picture of the general aspects of the most successful approaches used to combine proteins with nanosystems. This combination is mainly achieved by absorption, bioconjugation and encapsulation. Interactions of nanoparticles with biomolecules and caveats related to protein denaturation are also pointed out. A clear understanding of nanoparticle-protein interactions could make possible the design of precise and versatile hybrid nanosystems. This could further allow control of their pharmacokinetics as well as activity, and safety.