Fabrication of enzyme-less folic acid sensor probe based on facile ternary doped Fe2O3/NiO/Mn2O3 nanoparticles

State of the art and future research directions of materials science applied to electrochemical biosensor developments

Centralized laboratories in which analytical processes are automated to enable the analysis of large numbers of samples at relatively low cost are used for analytical testing throughout the world. However, healthcare is changing, partly due to the general recognition that care needs to be more patient-centered and putting the patient at the center of action. One way to achieve this goal is to consider point-of-care testing (PoC) devices as alternative analytical concepts. This requires miniaturization of current analytical concepts and the use of cost-effective diagnostic tools with appropriate sensitivity and specificity. Electrochemical sensors are ideally adapted as they provide robust, low-cost, and miniaturized solutions for the detection of variable analytes, yet lack the high sensitivity comparable to more classical diagnosis approaches. Advances in nanotechnology have opened up a plethora of different nanomaterials to be applied as electrode and/or sensing materials in electrochemical biosensors. The choice of materials significantly influences the sensor's sensitivity, selectivity, and overall performance. A critical review of the state of the art with respect to the development of the utilized materials (between 2019 and 2023) and where the field is heading to are the focus of this article.

Nanomaterials-based biosensor and their applications: A review

A sensor can be called ideal or perfect if it is enriched with certain characteristics viz., superior detections range, high sensitivity, selectivity, resolution, reproducibility, repeatability, and response time with good flow. Recently, biosensors made of nanoparticles (NPs) have gained very high popularity due to their excellent applications in nearly all the fields of science and technology. The use of NPs in the biosensor is usually done to fill the gap between the converter and the bioreceptor, which is at the nanoscale. Simultaneously the uses of NPs and electrochemical techniques have led to the emergence of biosensors with high sensitivity and decomposition power. This review summarizes the development of biosensors made of NPssuch as noble metal NPs and metal oxide NPs, nanowires (NWs), nanorods (NRs), carbon nanotubes (CNTs), quantum dots (QDs), and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

Preparation of Cex-Mn0.8Fe0.2O2 Catalysts and Its Anti-Sulfur Denitration Performance

In order to meet the industrial denitrification demands, inexpensive ferrous metals Mn and Fe have been chosen as the raw materials for the catalysts of CO-SCR, and the anti-sulfur denitrification performance of ferromanganese catalysts can be greatly enhanced by Ce doping. In this study, Cex-Mn0.8Fe0.2O2 catalysts were prepared by co-precipitation, and the effects of Ce addition on the structure and morphology of prepared catalysts and their anti-sulfur denitration performance were investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the Cex-Mn0.8Fe0.2O2 catalysts consisted of nanoparticles sized 20–100 nm. Specifically, the Ce0.2-Mn0.8Fe0.2O2 catalyst had more active sites and the best anti-sulfur denitration performance, with a denitration rate of 90.36% at 350 °C, while the denitrification performance of the Mn0.8Fe0.2O2 catalyst was only 85%. Furthermore, the denitrification rate of the catalyst was maintained above 80% when the CO:NO:SO2 ratio was 3:1:1 for 4 h at 350 °C.

Facile synthesis of mesoporous nano Ni/NiO and its synergistic role as super adsorbent and photocatalyst under sunlight irradiation

Tailoring a material that has a synergistic role as an adsorbent and a photocatalyst for environmental application is an attractive field for research. This article presents a study of facile synthesis of NiO and Ni/NiO with a synergistic role as super adsorbents in the lake of light and photocatalysts under light irradiation. Nano flower-like mesoporous NiO and Ni/NiO were synthesized by the co-precipitation method. XRD, SEM, EDAX, XPS, BET, and DR/UV-Vis spectroscopy techniques were employed for samples' analysis. The point of zero surface charge of prepared samples was detected by the batch equilibrium method. The adsorption efficiency was investigated in the absence of light using aniline blue as a pollutant model dye. The synergistic effect as an adsorbent and a photocatalyst was investigated under UV and sunlight irradiation. Different parameters affecting the adsorption in the dark have been optimized. The results showed that in the absence of light, the prepared samples are super adsorbents with a maximum adsorption capacity ranging from 210 to 230 mg g-1 and a removal % ranging from 95 to 100% within 2 h. Under UV or sunlight irradiation, the adsorbent/photocatalyst attained a dye removal % of 99.8% within 30 min. The adsorption data matched the pseudo-second-order model, and the equilibrium adsorption data showed compatibility with Langmuir model. The findings of experiments revealed that the adsorption is spontaneous, exothermic, and results in less entropy. Under sunlight irradiation, the dye removal efficiency increased by 19% in the case of Ni/NiO hybrid; it showed a removal efficiency of 99.5% within 30 min under sunlight irradiation versus 80% after 120 min in the dark.

Activation of Peroxymonosulfate Using Secondary Pyrolysis Oil-Based Drilling Cuttings Ash for Pollutant Removal

In this study, the utilization of secondary pyrolysis oil-based drilling cuttings ash (OBDCA-sp) to activate peroxymonosulfate (PMS) for pollutant removal was investigated. The chemical and physical properties of OBDCA-sp were explicitly analyzed via multiple characterization. The activation efficiency of OBDCA-sp for PMS was tested using humic acid (HA) as the target pollutant. 92% of HA and 52% of total organic carbon in solution could be removed using OBDCA-sp-activated PMS under optimal conditions: OBDCA-sp dosage at 4 g/L, PMS concentration at 4 mmol/L, HA concentration at 10 mg/L, and pH value at 7. After four cycles, 84% removal rate of HA could still be achieved using OBDCA-sp to activate PMS. The main catalysis elements for PMS activation in OBDCA were postulated to be Fe(III), Co(III), and Mn(III), based on X-ray photoelectron spectroscopy and X-ray diffraction results. The results of the quenching experiment indicated that SO4 •-, •OH, and 1O2 were the main reactive oxygen species (ROS) and that 1O2 was the dominant ROS in the HA removal process. Radical trapping experiments indicated the presence of SO4 •-, •OH, and 1O2 in the reaction system. This study presented a novel utilization path of OBDCA in the field of environmental remediation.

Biosensing platform on ferrite magnetic nanoparticles: Synthesis, functionalization, mechanism and applications

Ferrite magnetic nanoparticles (FMNPs) are gaining popularity to design biosensors for high-performance clinical diagnosis. The fusion of information shows that FMNPs based biosensors require well-tuned FMNPs as detection probes to produce large and specific biological signals with minimal non-specific binding. Nevertheless, there is a noticeable lacuna of information to solve the issues related to suitable synthesis route, particle size reduction, functionalization, sensitivity towards targeted intercellular biological tiny particles, and lower signal-to-noise ratio. Therefore it allows exploring unique characteristics of FMNPs to design a suitable sensing device for intracellular measurements and diseases detection. This review focuses on the extensively used synthesis routes, their advantages and limitations, crystalline structure, functionalization, along with recent applications of FMNPs in biosensors, taking into consideration their analytical figures of merit and range of linearity. This work also addresses the current progress, key factors for sensitivity, selectivity and productivity improvement along with the challenges, future trends and perspectives of FMNPs based biosensors.

A Review on Biosensors and Recent Development of Nanostructured Materials-Enabled Biosensors

A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal. The design and development of biosensors have taken a center stage for researchers or scientists in the recent decade owing to the wide range of biosensor applications, such as health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery. The main challenges involved in the biosensor progress are (i) the efficient capturing of biorecognition signals and the transformation of these signals into electrochemical, electrical, optical, gravimetric, or acoustic signals (transduction process), (ii) enhancing transducer performance i.e., increasing sensitivity, shorter response time, reproducibility, and low detection limits even to detect individual molecules, and (iii) miniaturization of the biosensing devices using micro-and nano-fabrication technologies. Those challenges can be met through the integration of sensing technology with nanomaterials, which range from zero- to three-dimensional, possessing a high surface-to-volume ratio, good conductivities, shock-bearing abilities, and color tunability. Nanomaterials (NMs) employed in the fabrication and nanobiosensors include nanoparticles (NPs) (high stability and high carrier capacity), nanowires (NWs) and nanorods (NRs) (capable of high detection sensitivity), carbon nanotubes (CNTs) (large surface area, high electrical and thermal conductivity), and quantum dots (QDs) (color tunability). Furthermore, these nanomaterials can themselves act as transduction elements. This review summarizes the evolution of biosensors, the types of biosensors based on their receptors, transducers, and modern approaches employed in biosensors using nanomaterials such as NPs (e.g., noble metal NPs and metal oxide NPs), NWs, NRs, CNTs, QDs, and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.