Non-small cell lung cancer (NSCLC) incited by epidermal growth factor receptor (EGFR) mutation makes up ∼85% of lung cancer diagnosed and death cases worldwide. The presented study introduced an alternative approach in detecting EGFR mutation using nano-silica integrated with polydimethylsiloxane (PDMS) polymer on interdigitated electrode (IDE) sensor. A 400 μm gap-sized aluminum IDE was modified with nano-polymer layer, which was made up of silica nanoparticles and PDMS polymer. IDE and PDMS-coated IDE (PDMS/IDE) were imaged using electron microscopes that reveals its smooth and ideal sensor morphology. The nano-silica-integrated PDMS/IDE surface was immobilized with EGFR probe and target to specify the lung cancer detection. The sensor specificity was justified through the insignificant current readouts with one-base mismatch and noncomplementary targets. The sensitivity of nano-silica-integrated PDMS/IDE was examined with mutant target spiked in human serum, where the resulting current affirms the detection of EGFR mutation. Based on the slope of the calibration curve, the sensitivity of nano-silica-integrated PDMS/IDE was 2.24E-9 A M-1 . The sensor recognizes EGFR mutation lowest at 1 aM complementary mutant target; however, the detection limit obtained based on 3σ calculation is 10 aM with regression value of 0.97.
Frictional and nanomechanical properties of nanostructured polymer surfaces are important to their technological and biomedical applications. In this work, poly(ethylene terephthalate) (PET) surfaces with a periodic distribution of well-defined nanopillars were fabricated through an anodization/embossing process. The apparent surface energy of the nanopillared surfaces was evaluated using the Fowkes acid-base approach, and the surface morphology was characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The normal and lateral forces between a silica microparticle and these surfaces were quantified using colloidal probe atomic force microscopy (CP-AFM). The friction-load relationship followed Amonton's first law, and the friction coefficient appeared to scale linearly with the nanopillar height. Furthermore, all the nanopillared surfaces showed pronounced frictional instabilities compared to the smooth sliding friction loop on the flat control. Performing the stick-slip amplitude coefficient (SSAC) analysis, we found a correlation between the frictional instabilities and the nanopillars density, pull-off force and work of adhesion. We have summarised the dependence of the nanotribological properties on such nanopillared surfaces on five relevant parameters, i.e. pull-off force fp, Amontons' friction coefficient μ, RMS roughness Rq, stick-slip amplitude friction coefficient SSAC, and work of adhesion between the substrate and water Wadh in a radar chart. Whilst demonstrating the complexity of the frictional behaviour of nanopillared polymer surfaces, our results show that analyses of multiparametric nanotribological properties of nanostructured surfaces should go beyond classic Amontons' laws, with the SSAC more representative of the frictional properties compared to the friction coefficient.
Soda lime silica (SLS) waste as the source of silica (SiO2) and ark clamshell (ACS) as the foaming agent has been utilized to fabricate the low-cost and lightweight foam glass-ceramics. A series of 1 and 6 wt% foam glass-ceramics were successfully prepared by the conventional solid-state sintering method at various sintering temperatures for 60 min. The bulk density of the samples has achieved minimum density (1.014 g/cm3) with maximum expansion (62.31%) at 6 wt% of the ACS content sintered at 800 °C for 60 min. The bulk density increases while the linear shrinkage and total porosity decrease with the progression of ACS contents and sintering temperature, where the results correspond with the FESEM micrograph. The result of XRD and FTIR transmittance spectra have shown that the formation of wollastonite crystal has occurred starting at 6 wt% of the ACS content sintered at 800 °C for 30 min. The highest mechanical performance (3.90 MPa) with an average total porosity (8.04%) is observed for the sample containing 1 wt% of ACS. It can be concluded that the composition of foam glass-ceramics (1 and 6 wt%) and sintering temperatures give significant results to the structural, physical, and mechanical properties of the fabricated foam glass-ceramics.
The ruthenium polypyridyl complex [Ru(dppz)2PIP]2+ (dppz: dipyridophenazine, PIP: (2-(phenyl)-imidazo[4,5-f ][1,10]phenanthroline), or Ru-PIP, is a potential anticancer drug that acts by inhibiting DNA replication. Due to the poor dissolution of Ru-PIP in aqueous media, a drug delivery agent would be a useful approach to overcome its limited bioavailability. Mesoporous silica nanoparticles (MSNs) were synthesized via a co-condensation method by using a phenanthrolinium salt with a 16 carbon length chain (Phen-C16) as the template. Optimization of the synthesis conditions by Box-Behnken design (BBD) generated MSNs with high surface area response at 833.9 m2g-1. Ru-PIP was effectively entrapped in MSNs at 18.84%. Drug release profile analysis showed that Ru-PIP is gradually released, with a cumulative release percentage of approximately 50% at 72 h. The release kinetic profile implied that Ru-PIP was released from MSN by diffusion. The in vitro cytotoxicity of Ru-PIP, both free and MSN-encapsulated, was studied in Hela, A549, and T24 cancer cell lines. While treatment of Ru-PIP alone is moderately cytotoxic, encapsulated Ru-PIP exerted significant cytotoxicity upon all the cell lines, with half maximal inhibitory concentration (IC50) values determined by MTT (([3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide]) assay at 48 h exposure substantially decreasing from >30 µM to <10 µM as a result of MSN encapsulation. The mechanistic potential of cytotoxicity on cell cycle distribution showed an increase in G1/S phase populations in all three cell lines. The findings indicate that MSN is an ideal drug delivery agent, as it is able to sustainably release Ru-PIP by diffusion in a prolonged treatment period.
The dispersion of hyperaccumulators used in the phytoremediation process has caused environmental concerns because of their heavy metal (HM) richness. It is important to reduce the environmental risks and prevent the HM to reenter the ecological cycle and thereby the human food web. In this work, supercritical water gasification (SCWG) technology was used to convert Sedum plumbizincicola into hydrogen (H2) gas and to immobilize HMs into biochar. The H2 production correlated with temperature ranging from 380 to 440 ℃ with the highest H2 yield of 2.74 mol/kg at 440 ℃. The free-radical reaction and steam reforming reaction at high temperatures were likely to be the mechanism behind the H2 production. The analyses of bio-oil by the Gas Chromatography-Mass Spectrometer (GC-MS) and Nuclear magnetic resonance spectroscopy (NMR) illustrated that the aromatic compounds, oxygenated compounds, and phenols were degraded into H2-rich gases. The increase of temperature enhanced the HM immobilization efficiency (>99.2 % immobilization), which was probably due to the quickly formed biochar that helped adsorb HMs. Then those HMs were chemically converted into stable forms through complexation with inorganic components on biochar, e.g., silicates, SiO2, and Al2O3. Consequently, the SCWG process was demonstrated as a promising approach for dispersing hyperaccumulators by immobilizing the hazardous HMs into biochar and simultaneously producing value-added H2-rich gases.
Multiple contaminants including heavy metals and phenolic compounds are normally co-exist in wastewater, which caused the treatment process is rather complicated. Herein, the synergistic photoredox of Cr(VI) and p-cresol (pC) by innovative fibrous silica zirconia (FSZr) photocatalyst was reported. The high surface area of FSZr comprised of microspheres with a bicontinuous concentric lamella structure morphology consisted of silica, while its core consisted of ZrO2 structure. The rearrangement of FSZr framework increased the crystallinity, formed Si-O-Zr bonds and narrowed the band gap of ZrO2 for enhanced of photoredox of Cr(VI) and pC. Compared to the reaction, the photoredox efficiency of FSZr for removing Cr(VI) and pC in simultaneous system was found to be 96 % and 59 %, respectively which are higher than that in its single system owing to the efficient electron-hole charge separation. Phenolic compound with high degree of electron donating group gave beneficial effect to photoreduction of Cr(VI). Consequently, a proposed mechanism involving multi-photoredox pathway were proposed based on photoredox reaction and scavengers studies. FSZr sustained the simultaneous photoredox activities after five runs demonstrating its possibility to be use in the wastewater treatment of various pollutants.
Cancer is a community health hazard which progress at a fatal rate in various countries across the globe. An agent used for chemotherapy should exhibit ideal properties to be an effective anticancer medicine. The chemotherapeutic medicines used for treatment of various cancers are, gemcitabine, paclitaxel, etoposide, methotrexate, cisplatin, doxorubicin and 5-fluorouracil. However, many of these agents present nonspecific systemic toxicity that prevents their treatment efficiency. Of all, gemcitabine has shown to be an active agent against colon, pancreatic, colon, ovarian, breast, head and neck and lung cancers in amalgamation with various anticancer agents. Gemcitabine is considered a gold-standard and the first FDA approved agent used as a monotherapy in management of advanced pancreatic cancers. However due to its poor pharmacokinetics, there is need of newer drug delivery system for efficient action. Nanotechnology has shown to be an emerging trend in field of medicine in providing novel modalities for cancer treatment. Various nanocarriers have the potential to deliver the drug at the desired site to obtain information about diagnosis and treatment of cancer. This review highlights on various nanocarriers like polymeric nanoparticles, solid lipid nanoparticles, mesoporous silica nanoparticles, magnetic nanoparticles, micelles, liposomes, dendrimers, gold nanoparticles and combination approaches for delivery of gemcitabine for cancer therapy. The co-encapsulation and concurrent delivery of Gem with other anticancer agents can enhance drug action at the cancer site with reduced side effects.
Nanotechnology is playing a major role in the field of medical diagnosis, in particular with the biosensor and bioimaging. It improves the performance of the desired system dramatically by displaying higher selectivity and sensitivity. Carbon nanomaterial, gold nanostructure, magnetite nanoparticle, and silica substrate are the most popular nanomaterials greatly contributed to make the affordable and effective biosensor at low-cost. This research work is introducing a new sensing strategy with graphene oxide-constructed triangular electrodes to diagnose Alzheimer's disease (AD). MicroRNA-137 (miRNA-137) was found as a suitable biomarker for AD, and the sensing method was established here to detect miRNA-137 on the complementary sequence. To enhance the immobilization of capture miRNA-137, gold nanostar (GNS) was conjugated with capture miRNA and immobilized on the GO-modified surface through an amine linker. This immobilization process enhanced the hybridization of the target and reaches the detection limit at 10 fM with the sensitivity of 1 fM on the linear curve with a regression coefficient of 0.9038. Further control sequences of miRNA-21 and single and triple base mismatched miRNA-137 did not show a significant response in current changes, indicating the specific miRNA-137 detection for diagnosing AD.
A chemical method to synthesize amorphous silica nanoparticles from the incinerated paddy straw has been introduced. The synthesis was conducted through the hydrolysis by alkaline-acidic treatments. As a result, silica particles produced with the sizes were ranging at 60-90 nm, determined by high-resolution microscopy. The crystallinity was confirmed by surface area electron diffraction. Apart from that, chemical and diffraction analyses for both rice straw ash and synthesized silica nanoparticles were conducted by X-ray diffraction and Fourier-transform infrared spectroscopy. The percentage of silica from the incinerated straw was calculated to be 28.3. The prominent surface chemical bonding on the generated silica nanoparticles was with Si-O-Si, stretch of Si-O and symmetric Si-O bonds at peaks of 1090, 471, and 780 cm-1, respectively. To confirm the impurities of the elements in the produced silica, were analyzed using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The stability of silica nanoparticles was investigated using thermogravimetric analysis and zeta potential. The measured size from zeta potential analysis was 411.3-493 nm and the stability of mass reduction was located at 200 °C with final amount of mass reduced ∼88% and an average polydispersity Index was 0.195-0.224.
The fall armyworm (Spodoptera frugiperda) is a major economic pest in the United States and has recently become a significant concern in African and Asian countries. Due to its increased resistance to current management strategies, including pesticides and transgenic corn, alternative management techniques have become more necessary. Currently, silicon (Si) is being used in many pest control systems due to its ability to increase plant resistance to biotic and abiotic factors and promote plant growth. The current experiments were carried out at the College of Plant Protection, Gansu Agricultural University, Lanzhou, China, to test the effect of Si on lifetable parameters and lipase activity of fall armyworm and vegetative and physiological parameters of maize plants. Two sources of Si (silicon dioxide: SiO2 and potassium silicate: K2SiO3) were applied on maize plants with two application methods (foliar application and soil drenching). The experiment results revealed that foliar applications of SiO2 and K2SiO3 significantly (P≤0.05) increased mortality percentage and developmental period and decreased larval and pupal biomass of fall armyworm. Similarly, both Si sources significantly (P≤0.05) reduced lipase activity of larvae, and fecundity of adults, whereas prolonged longevity of adults. Among plant parameters, a significant increase in fresh and dry weight of shoot, stem length, chlorophyll content, and antioxidant activity was observed with foliar applications of Si. Root fresh and dry weight was significantly (P ≤ 0.05) higher in plants treated with soil drenching of SiO2 and K2SiO3. Moreover, SiO2 performed better for all parameters as compared to K2SiO3 and control treatment. The study conclusively demonstrated a significant negative effect on various biological parameters of fall armyworm when plants were treated with Si, so it can be a promising strategy to control this pest.
A sustainable super-hydrophobic coating composed of silica from palm oil fuel ash (POFA) and polydimethylsiloxane (PDMS) was synthesised using isopropanol as a solvent and coated on a glass substrate. FESEM and AFM analyses were conducted to study the surface morphology of the coating. The super-hydrophobicity of the material was validated through goniometry, which showed a water contact angle of 151°. Cytotoxicity studies were conducted by assessing the cell viability and cell morphology of mouse fibroblast cell line (L929) and hamster lung fibroblast cell line (V79) via tetrazolium salt 3-(4-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and microscopic methods, respectively. The clonogenic assay was performed on cell line V79 and the cell proliferation assay was performed on cell line L929. Both results validate that the toxicity of PDMS: SS coatings is dependent on the concentration of the super-hydrophobic coating. The results also indicate that concentrations above 12.5 mg/mL invariably leads to cell toxicity. These results conclusively support the possible utilisation of the synthesised super-hydrophobic coating for biomedical applications.
In the present study, electrochemical sensing for urea was proposed utilizing graphene-based quaternary nanocomposites YInWO4-G-SiO2 (YIWGS). These YIWGS nanocomposites were utilized due to their exceptionally delicate determination of urea with the lowest detection limit (0.01 mM). These YIWGS composites were developed through a simple self-assembly method. From physical characterization, we found that the YIWGS composites are crystalline in nature (powdered X-ray diffraction), and Fourier transform infrared (FTIR) spectroscopy analysis provided the surface functionality and bonding. Scanning electron microscopy (SEM) studies indicated the morphology characteristics of the as-synthesized composites and the high-resolution transmission electron microscopy (HRTEM) image supported the formation of cubic or hexagonal morphology of the YIW nanocomposites. The YIWGS sensor showed a great electroanalytical sensing performance of 0.07 mM urea with a sensitivity of 0.06 mA cm-2, an expansive linear range of 0.7-1.5 mM with a linear response (R2 1/4 0.99), and an eminent reaction time of around 2 s. It also displayed a good linear response toward urea with negligible interferences from normal coinciding species in urine samples.
The conversion of aldehydes to valuable alkanes via cyanobacterial aldehyde deformylating oxygenase is of great interest. The availability of fossil reserves that keep on decreasing due to human exploitation is worrying, and even more troubling is the combustion emission from the fuel, which contributes to the environmental crisis and health issues. Hence, it is crucial to use a renewable and eco-friendly alternative that yields compound with the closest features as conventional petroleum-based fuel, and that can be used in biofuels production. Cyanobacterial aldehyde deformylating oxygenase (ADO) is a metal-dependent enzyme with an α-helical structure that contains di‑iron at the active site. The substrate enters the active site of every ADO through a hydrophobic channel. This enzyme exhibits catalytic activity toward converting Cn aldehyde to Cn-1 alkane and formate as a co-product. These cyanobacterial enzymes are small and easy to manipulate. Currently, ADOs are broadly studied and engineered for improving their enzymatic activity and substrate specificity for better alkane production. This review provides a summary of recent progress in the study of the structure and function of ADO, structural-based engineering of the enzyme, and highlight its potential in producing biofuels.
Graphene oxide is a very high capacity adsorbent due to its functional groups and π-π interactions with other compounds. Adsorption capacity of graphene oxide, however, can be further enhanced by having synergistic effects through the use of mixed-matrix composite. In this study, silica-decorated graphene oxide (SGO) was used as a high-efficiency adsorbent to remove Congo red (CR) and Cadmium (II) from aqueous solutions. The effects of solution initial concentration (20 to 120 mg/l), solution pH (pH 2 to 7), adsorption duration (0 to 140 min) and temperature (298 to 323 K) were measured in order to optimize the adsorption conditions using the SGO adsorbent. Morphological analysis indicated that the silica nanoparticles could be dispersed uniformly on the graphene oxide surfaces. The maximum capacities of adsorbent for effective removal of Cd (II) and CR were 43.45 and 333.33 mg/g based on Freundlich and Langmuir isotherms, respectively. Langmuir and Freundlich isotherms displayed the highest values of Qmax for CR and Cd (II) adsorption in this study, which indicated monolayer adsorption of CR and multilayer adsorption of Cd (II) onto the SGO, respectively. Thermodynamic study showed that the enthalpy (ΔH) and Gibbs free energy(ΔG) values of the adsorption process for both pollutants were negative, suggesting that the process was spontaneous and exothermic in nature. This study showed active sites of SGO (π-π, hydroxyl, carboxyl, ketone, silane-based functional groups) contributed to an enormous enhancement in simultaneous removal of CR and Cd (II) from an aqueous solution, Therefore, SGO can be considered as a promising adsorbent for future water pollution control and removal of hazardous materials from aqueous solutions.
Grog is an additive material that plays important roles in ceramic making. It improves the fabrication process of green bodies as well as the physical properties of fired bodies. Few low-cost materials and wastes have found their application as grog in recent years, thus encouraging the replacement of commercial grogs with cost-saving materials. Coal fly ash, a combustion waste produced by coal-fired power plant, has the potential to be converted into grog owing to its small particle sizes and high content of silica and alumina. In this study, grog was derived from coal fly ash and mixed with kaolin clay to produce ceramics. Effects of the grog addition on the resultant ceramics were investigated. It was found that, to a certain extent, the grog addition reduced the firing shrinkage and increased the total porosity of the ceramics. The dimensional stability of the ceramics at a firing temperature of 1200 °C was also not noticeably affected by the grog. However, the grog addition in general had negative effects on the biaxial flexural strength and refractoriness of the ceramics.
The recent implication of circular economy in Australia spurred the demand for waste material utilization for value-added product generations on a commercial scale. Therefore, this experimental study emphasized on agricultural waste biomass, rice husk (RH) as potential feedstock to produce valuable products. Rice husk biochar (RB) was obtained at temperature: 180 °C, pressure: 70 bar, reaction time: 20 min with water via hydrothermal carbonization (HTC), and the obtained biochar yield was 57.9%. Enhancement of zeta potential value from - 30.1 to - 10.6 mV in RB presented the higher suspension stability, and improvement of surface area and porosity in RB demonstrated the wastewater adsorption capacity. Along with that, an increase of crystallinity in RB, 60.5%, also indicates the enhancement of the catalytic performance of the material significantly more favorable to improve the adsorption efficiency of transitional compounds. In contrast, an increase of the atomic O/C ratio in RB, 0.51 delineated high breakdown of the cellulosic component, which is favorable for biofuel purpose. 13.98% SiO2 reduction in RB confirmed ash content minimization and better quality of fuel properties. Therefore, the rice husk biochar through HTC can be considered a suitable material for further application to treat wastewater and generate bioenergy.
Strategies to immobilize the individual enzymes are crucial for enhancing catalytic applicability and require a controlled immobilization process. Herein, protocol for immobilizing Candida rugosa lipase (CRL) onto modified magnetic silica derived from oil palm leaves ash (OPLA) was optimized for the effects of concentration of CRL, immobilization time, and temperature, monitored by titrimetric and spectrometric methods. XRD and TGA-DTG spectrometric observations indicated that OPLA-silica was well coated over magnetite (SiO2-MNPs) and CRLs were uniformly bound by covalent bonds to SiO2-MNPs (CRL/Gl-A-SiO2-MNPs). The optimized immobilization protocol showed that in the preparation of CRL/Gl-A-SiO2-MNPs, CRL with 68.3 mg/g protein loading and 74.6 U/g specific activity was achieved using 5 mg/mL of CRL, with an immobilization time of 12 h at 25 °C. The present work also demonstrated that acid-pretreated OPLA is a potential source of renewable silica, envisioning its applicability for practical use in enzymatic catalysis on solid support.
Recently, studies on the development and investigation of carbohydrate-functionalized silica nanoparticles (NPs) and their biomedicine applications such as cell-specific targeting and bioimaging has been carried out extensively. Since the number of breast cancer patients has been growing in recent years, potential NPs were being studied in this project for targeting breast cancer cells. Mannose receptors can be found on the surface of MDA-MB-231, which is a kind of human breast cancer cell line. Therefore, we decorated a cyanine 3 fluorescent dye (Cy3) and mannosides on the surface of silica NPs for the purpose of imaging and targeting. Galactoside was also introduced onto the surface of silica NPs acting as a control sample. Various sizes of silica NPs were synthesized by using different amounts of ammonium to investigate the effect of the size of NPs on the cellular uptake rate. The physical properties of these NPs were characterized by scanning electron microscope, dynamic light scattering, and their zeta potential. Cellular experiments demonstrated that mannoside-modified NPs can be uptaken by MDA-MB-231. From the experiment, we found out that the best cellular uptake rate of nanoparticle size is about 250 nm. The MTT assay showed that Man@Cy3SiO2NPs are not cytotoxic, indicating they may have the potential for biomedical applications.
This study aimed to investigate the effects of nanohydroxyapatite-silica-glass ionomer cement (nanoHA-silica-GIC) on the differentiation of dental pulp stem cells (DPSCs) into odontogenic lineage. DPSCs were cultured in complete Minimum Essential Medium Eagle-Alpha Modification (α-MEM) with or without nanoHA-silica-GIC extract and conventional glass ionomer cement (cGIC) extract. Odontogenic differentiation of DPSCs was evaluated by real-time reverse transcription polymerase chain reaction (rRT-PCR) for odontogenic markers: dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), osteocalcin (OCN), osteopontin (OPN), alkaline phosphatase (ALP), collagen type I (COL1A1), and runt-related transcription factor 2 (RUNX2) on day 1, 7, 10, 14, and 21, which were normalized to the house keeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Untreated DPSCs were used as a control throughout the study. The expressions of DSPP and DMP1 were higher on days 7 and 10, that of OCN on day 10, those of OPN and ALP on day 14, and that of RUNX2 on day 1; COL1A1 exhibited a time-dependent increase from day 7 to day 14. Despite the above time-dependent variations, the expressions were comparable at a concentration of 6.25 mg/mL between the nanoHA-silica-GIC and cGIC groups. This offers empirical support that nanoHA-silica-GIC plays a role in the odontogenic differentiation of DPSCs.
The chemical reactions of dry-disposed ash dump, ingressed oxygen, carbon dioxide, and infiltrating rainwater affect mineralogical transformation, redistribution, and migration of chemical species. Composite samples of weathered coal fly ash taken at various depths and fresh coal fly ash were examined using organic petrographic, X-ray diffraction, X-ray fluorescence techniques, and successive extraction procedures. Results obtained show relative enrichment of glass, Al-Fe-oxides, calcite, and tridymite in the weathered CFA, but the fresh CFA is enriched in mullite, inertinite, maghemite, and ettringite. The enrichment of the weathered CFA in amorphous glass suggests higher reactivity when compared to fresh CFA. The evident depletion of soluble oxides in the weathered CFA is attributed to flushing of the soluble salts by percolating rainwater. Comparative enrichment of examined elements in water-soluble, exchangeable, reducible, and residual fractions of the weathered CFA is partly due to the slow release of adsorbed chemical species from the alumina-silicate matrix and diffusion from the deeper sections of the particles of coal fly ash. Sodium and potassium show enrichment in the oxidisable fraction of fresh CFA. The estimated mobility factor indicates mobility for Ca, Mg, Na, Se, Mo, and Sb and K, Sr, V, Cu, Cr, Se, and B in fresh and weathered CFAs, respectively.