An electrochemical aptasensor was designed for the ultraselective and sensitive detection of Pb2+ by using lead‐specific binding DNA oligonucleotide as the molecular recognition element on Au ...nanoparticles/Nb4C3Tx MXene (Au@Nb4C3Tx) modified electrode. The Au@Nb4C3Tx is conjugated with thiol‐modified lead‐binding DNA through the Au−S bond. The DNA−Au@Nb4C3Tx modified glassy carbon electrode exhibited ultrahigh selectivity and enhanced response towards the detection of Pb2+ with a detection limit of 4 nM and linear range of 10 nM to 5 μM. This work has proved the possibility of using Nb4C3Tx as a robust immobilization platform for DNA oligonucleotides towards different environmental sensing and biomedical applications.
This paper evaluates the electrochemical performance of platinum nanoparticles/Ti3C2Tx nanocomposite (Pt@Ti3C2Tx) towards environmental sensing applications. The nanocomposite was prepared by ...self-reduction of Pt salt to Pt nanoparticles (PtNPs) on the surface of delaminated Ti3C2Tx nanosheets, in which Ti3C2Tx simultaneously acted as reducing agent as well as conductive matrix. The Pt@Ti3C2Tx nanocomposites with different Pt loading have been electrochemically characterized and it was found that 10%Pt@Ti3C2Tx has the highest electrochemical activity in the anodic potential window. Hence, 10%Pt@Ti3C2Tx has been used to develop an electrochemical sensor for the detection of Bisphenol A (BPA), which is one of the common environmental pollutants. At the optimal conditions, the oxidation peak of BPA was proportional to the analyte concentration from 50 nM to 5 μM with a detection limit of 32 nM. The practical application of the proposed sensor was successfully evaluated in drinking water and fresh milk samples.
Display omitted
•Electrochemical performance of Pt@Ti3C2Tx (MXene) nanocomposites with different Pt loading is evaluated.•10%Pt@Ti3C2Tx (MXene) nanocomposite showed high electrochemical activity.•10%Pt@Ti3C2Tx can be used for the sensitive detection of bisphenol A.•The sensor achieved a detection limit of 32 nM with a linear range from 50 nM to 5 μM.
Rapid and real-time detection of l-cysteine (l-Cys) is important for early diagnostics of several diseases and biological disorders. We report here a stable and highly sensitive electrochemical ...sensor for the detection of l-Cys based on a Pd@Ti3C2Tx (MXene)-modified glassy carbon electrode (GCE). The Pd@Ti3C2Tx nanocomposite was prepared by in situ reduction of Pd(ii) salt on the surface of delaminated (DL) Ti3C2Tx nanosheets to form pseudo-spherical palladium nanoparticles (PdNPs) with 2–6 nm size distributions. The MXene acts as the conductive matrix and a reducing agent at the electrode surface, while PdNPs are there to improve the stability of Ti3C2Tx and to enhance the electrocatalytic activity towards l-Cys detection. The Pd@Ti3C2Tx/GCE sensor exhibited a detection limit of 0.14 μM and a linear electro-oxidative response to l-Cys within the concentration range from 0.5 to 10 μM. The sensor also demonstrated excellent selectivity over common interfering ions such as ascorbic acid, uric acid, dopamine and glucose.
Display omitted
•Interlinked chitosan-ZnO (CZNC-10) nanocomposite inhibited the biocorrosion of SRB on carbon steel.•CZNC-10 co-formed protective film on carbon steel to prevent bacterial attack ...during initial days of incubation.•CZNC-10 inhibitor caused damage to SRB cells and significant reduction of corrosion products.•Charge transfer resistance (Rct) increased 3.2 times than the control after 21 days of incubation in presence of CZNC-10.
In this report, interlinked chitosan-ZnO nanocomposite at 10% ZnO (CZNC-10) is successfully used as green biocide for biofilm control and reduction of biocorrosion on carbon steel material. It was found that 250 μg/mL CZNC-10 can be used efficiently for the inhibition of sulfate reducing bacteria (SRB) biofilm on carbon steel. The Rct values after 21 and 28 days of incubation in presence of CZNC-10 are almost 3.2 and 2.8 times higher than the control respectively, indicating a strong corrosion inhibition with 74% as maximum inhibition efficiency.
In this work, uniform cross-linked chitosan/lignosulfonate (CS/LS) nanospheres with an average diameter of 150–200 nm have been successfully used as a novel, environmentally friendly biocide for the ...inhibition of mixed sulfate-reducing bacteria (SRB) culture, thereby controlling microbiologically influenced corrosion (MIC) on carbon steel. It was found that 500 µg·mL−1 of the CS/LS nanospheres can be used efficiently for the inhibition of SRB-induced corrosion up to a maximum of 85% indicated by a two fold increase of charge transfer resistance (Rct) on the carbon steel coupons. The hydrophilic surface of CS/LS can readily bind to the negatively charged bacterial surfaces and thereby leads to the inactivation or damage of bacterial cells. In addition, the film formation ability of chitosan on the coupon surface may have formed a protective layer to prevent the biofilm formation by hindering the initial bacterial attachment, thus leading to the reduction of corrosion.
The control of microbiologically influenced corrosion (MIC) is of great significance in many industrial applications. Attention has been devoted to emerging nanomaterials as ‘green’ biocides for ...their remarkable antimicrobial function and relatively low environmental risk. Understanding the antimicrobial inhibition mechanisms is the key to increase the efficiency of nanoparticles and enhance the feasibility of their application against various MIC microorganisms under different environmental conditions. This study gives an overview of the recent advancements of different nanomaterials and nanocomposites used as biocides for the inhibition of MIC. The potential and associated challenges in developing NPs as effective biocides are highlighted.
Display omitted
•The electrochemical performance of Nb2CTx and Nb4C3Tx MXenes in aqueous media was evaluated.•Both Nb2CTx and Nb4C3Tx are electrochemically stable up to an anodic potential of ...0.5 V.•It was found that Nb4C3Tx is more electrochemically active than Nb2CTx.•Nb4C3Tx can be used as an immobilization platform for the sensitive detection of dopamine with a detection limit of 23 nM.
In this work, we study the electrochemical performance of Nb2CTx and Nb4C3Tx MXenes in the aqueous media and their application as a sensing platform for small biomolecules. Both Nb2CTx and Nb4C3Tx are electrochemically stable up to an anodic potential of 0.5 V. It was found that Nb4C3Tx is more electrochemically active than Nb2CTx. Based on this, Nb4C3Tx was evaluated for the electrochemical detection of aqueous media solutions containing ascorbic acid, uric acid and dopamine. This work opens the door for the wider application of Nb-based MXenes in aqueous electrochemical sensing applications.
Zinc oxide (ZnO) nanorods and ZnO nanostructures composited with silver (Ag) and multi-walled carbon nanotubes (MWCNTs) have been synthesized by a simple impregnation-calcination method and have been ...shown to be suitable for use as antimicrobial agents. The preparation method used for composite materials is very simple, time-effective, and can be used for large-scale production. Several analytical techniques, including X-ray diffraction (XRD), scanning electron spectroscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transmission infrared spectroscopy (FTIR), have been used to characterize the prepared ZnO-Ag-MWCNT composite materials. The effects on structural, morphological, and antimicrobial properties of (ZnO)
(Ag)
nanocomposites at various weight ratios (x = 0, 5, 10, 30, and 50 wt%) have been investigated. The antimicrobial properties of ZnO composited with Ag nanoparticles and MWCNTs towards both gram-positive and gram-negative bacteria species were studied. The effect of raw MWCNTs and MWCNTs composited with ZnO and Ag on the cell morphology and chemical composition of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was studied by SEM and EDS, respectively. It was found that composite materials made of ZnO-Ag-MWCNTs exhibit greater antibacterial activities toward the microorganisms E. coli and S. aureus than ZnO-Ag, which could be beneficial for efficient antimicrobial agents in water and air treatment applications.
Wastewater-based epidemiology (WBE) has been proven effective for the monitoring of infectious disease outbreaks during mass gathering events and for timely public health interventions. As part of ...Qatar's efforts to monitor and combat the spread of infectious diseases during the FIFA World Cup Qatar 2022™ (FWC’22), wastewater surveillance was used to monitor the spread of SARS-CoV-2, human enterovirus, and poliovirus. The screening covered five major wastewater treatment plants servicing the event locations between October 2022 and January 2023. Viruses were concentrated from the wastewater samples by PEG precipitation, followed by qRT-PCR to measure the viral load in the wastewater. As expected, SARS-CoV-2 and enterovirus RNA were detected in all samples, while poliovirus was not detected. The concentration of SARS-CoV-2 was correlated with population density, such as areas surrounding the World Cup venues, and with the number of reported clinical cases. Additionally, we observed temporal fluctuations in viral RNA concentrations, with peak levels coinciding with the group stage matches of the FWC’22. This study has been useful in providing public health authorities with an efficient and cost-effective surveillance system for potential infectious disease outbreaks during mega-events.
Display omitted
•Wastewater surveillance was utilized to monitor SARS-CoV-2, enterovirus, and poliovirus during the FIFA World Cup Qatar 2022.•SARS-CoV-2 and enterovirus RNA were detected in all samples, while poliovirus was not detected.•Sequencing revealed that Omicron XBB.1 was the predominant subvariant during the games period.•Wastewater-based epidemiology offers an efficient, economical way to detect disease outbreaks during major events.
Severe environmental conditions can have a diverse impact on marine microorganisms, including bacteria. This can have an inevitable impact on the biofouling of membrane-based desalination plants. In ...this work, we have utilized indicator bacteria such as total coliform, fecal coliform, and
, as well as 16S rRNA sequencing, to investigate the impact of environmental conditions and spatial variations on the diversity of bacterial communities in the coastal waters and sediments from selected sites in Qatar. The concentration levels of indicator bacteria were affected by increasing temperatures and pH, and by decreasing salinity of seawater samples. Diversity indices and the molecular phylogeny demonstrated that
,
, and
were the dominant phyla in all locations. The most abundant operational taxonomic units (OTUs) at the family level were from
(27.07%, 4.31%) and
(22.51%, 9.86%) in seawater and sediment, respectively.
(33.87%, 16.82%),
(30.68%, 5.84%), and
(20.35%, 12.45%) were abundant at the species level in both seawater and sediment, while
(13.72%) was abundant in sediment only. The results suggest that sediment can act as a reservoir for indicator bacteria, with higher diversity and lower abundance compared to seawater.
PDF
