Among the many biological entities employed in the development of biosensors, enzymes have attracted the most attention. Nanotechnology has been fostering excellent prospects in the development of enzymatic biosensors, since enzyme immobilization onto conductive nanostructures can improve characteristics that are crucial in biosensor transduction, such as surface-to-volume ratio, signal response, selectivity, sensitivity, conductivity, and biocatalytic activity, among others. These and other advantages of nanomaterial-based enzymatic biosensors are discussed in this work via the compilation of several reports on their applications in different industrial segments. To provide detailed insights into the state of the art of this technology, all the relevant concepts around the topic are discussed, including the properties of enzymes, the mechanisms involved in their immobilization, and the application of different enzyme-derived biosensors and nanomaterials. Finally, there is a discussion around the pressing challenges in this technology, which will be useful for guiding the development of future research in the area.

https://www.mdpi.com/2673-3293/2/1/12/pdf

Designing of Nanomaterials-Based Enzymatic Biosensors: Synthesis, Properties, and Applications

Electrochemical sensors play a significant role in detecting chemical ions, molecules, and pathogens in water and other applications. These sensors are sensitive, portable, fast, inexpensive, and suitable for online and in-situ measurements compared to other methods. They can provide the detection for any compound that can undergo certain transformations within a potential window. It enables applications in multiple ion detection, mainly since these sensors are primarily non-specific. In this paper, we provide a survey of electrochemical sensors for the detection of water contaminants, i.e., pesticides, nitrate, nitrite, phosphorus, water hardeners, disinfectant, and other emergent contaminants (phenol, estrogen, gallic acid etc.). We focus on the influence of surface modification of the working electrodes by carbon nanomaterials, metallic nanostructures, imprinted polymers and evaluate the corresponding sensing performance. Especially for pesticides, which are challenging and need special care, we highlight biosensors, such as enzymatic sensors, immunobiosensor, aptasensors, and biomimetic sensors. We discuss the sensors' overall performance, especially concerning real-sample performance and the capability for actual field application.

https://www.mdpi.com/1424-8220/21/12/4131/pdf

A Review of Nanocomposite-Modified Electrochemical Sensors for Water Quality Monitoring.

Methyl parathion (MP), as a typical organophosphorus pesticide, has been widely used in pest control and plant growth regulation. Simultaneously, the problem of pesticide residues also poses a serious threat to the environment and human health. Currently, pesticide residue detection technology still faces great challenges in practical applications due to the problems of expensive facilities and complicated operations in conventional analysis methods. To address these problems, a novel nonenzymatic electrochemical pesticide sensor was reported. A zirconium-based metal organic framework material with terephthalic acid as a ligand (Zr-BDC) was designed to combine with electro-reduced graphene oxides (rGO). The Zr-BDC-rGO nanocomposite contains Zr-OH groups with high affinity for phosphate groups, endowing it with selective recognition and a higher adsorption capacity for MP. Moreover, rGO has a high specific surface area and excellent electron transport capability, making it an excellent functionalized adsorption and substrate material, which could improve the conductivity of the material and achieve a lower detection limit. Upon optimization, this sensor provided a wide linear range from 0.001 to 3.0 μg mL−1 and low limit of detection 0.5 ng mL−1 for MP. This work provides a rapid, sensitive and cost-effective sensing platform for pesticide residue detection.

A novel electrochemical sensor via Zr-based metal organic framework–graphene for pesticide detection

Heavy metal ions and pesticides are extremely dangerous for human health and environment and an accurate detection is an essential step to monitor their levels in water. The standard and most used methods for detecting these pollutants are sophisticated and expensive analytical techniques. However, recent technological advancements have allowed the development of alternative techniques based on optical properties of noble metal nanomaterials, which provide many advantages such as ultrasensitive detection, fast turnover, simple protocols, in situ sampling, on-site capability and reduced cost. This paper provides a review of the most common photo-physical effects impact on the fluorescence of metal nanomaterials and how these processes can be exploited for the detection of pollutant species. The final aim is to provide readers with an updated guide on fluorescent metallic nano-systems used as optical sensors of heavy metal ions and pesticides in water.

Metal Nanostructures for Environmental Pollutant Detection Based on Fluorescence

In this work, metal organic frameworks (A100 Al-based MOFs) were used in dispersive solid-phase microextraction (DSPME) for the isolation and preconcentration of the carbaryl from vegetable, fruit and water samples. The A100 Al-based MOFs showed excellent behavior for the adsorption of carbaryl from a water–ethanol solution; additionally, carbaryl was easily desorbed with ethyl acetate for detection by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-TMS). The analytical process of DSPME together with UPLC-TMS provides the accurate monitoring of trace carbaryl residues. The results show that the optimal recovery% of carbaryl was obtained at a sample apparent pH of 5, with the application of 1 mL of ethyl acetate to elute the carbaryl from the A100 Al-based MOFs. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.01 mg.L−1 and 0.03 mg.L−1, respectively. The RSD% was 0.8–1.9, and the preconcentration factor was 45. DSPME and UPLC-TMS were successfully used for the isolation and detection of carbaryl in food and water samples.

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Metal Organic Framework-Based Dispersive Solid-Phase Microextraction of Carbaryl from Food and Water Prior to Detection by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin 130024, China Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan 650500, China State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China Northwest Land and Resources Research Center, Shaanxi Normal Northwest University, China State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, Northeast Normal University, Changchun, Jilin 130024, China Ecology and Environment Department of Jilin Province, Changchun, Jilin 130024, China Heilongjiang Provincial Key Laboratory of Ecological Restoration and Resource Utilization for Cold Region, Heilongjiang University, Harbin 150080, China School of Life Science and Geology, Yili Normal University, Yili, Xinjiang 835000, China

https://downloads.hindawi.com/journals/js/2020/8503491.pdf

Sensors Applied for the Detection of Pesticides and Heavy Metals in Freshwaters

Impacts of pollution, sex, and tide on the time allocations to behaviours of Uca arcuata in mangroves.

The invention discloses an amphibians crossing channel ecological module which comprises a channel body passage, a channel bottom climbing plate, a light reflection and heat insulation plate, a support and a guide protection plate The front end and the back end of the channel body passage are provided with fixing devices and are arranged on the two sides of a channel; the channel body passage is in a slot shape, and a water absorbing material is contained in the slot and is made of cotton, fiber, silk floss, felt and/or hay; the light reflection and heat insulation plate is in a hopper shape, a water storage tank is arranged below the light reflection and heat insulation plate, and the hopper-shaped light reflection and heat insulation plate is used for collecting rainwater and supplanting the water storage tank for water, the water storage tank drips water into the water absorbing material in the slot of the channel body passage through water outlet pipes, and the water absorbing material keeps wet; and soil bases are arranged on the two sides of the channel body passage, a hidden rest place is formed by dead branches placed at the edges and stone riprap, and amphibians are induced to pass through the channel

Amphibians crossing channel ecological module

The invention discloses a protection structure for controlling erosion of gully sides in loess hilly regions. The protection structure comprises a first gully side protection ridge (1), a second gullyside protection ridge (2), a biochar zone (3) and a sand fixing coating (4). A management method for controlling erosion of the gully sides in the loess hilly regions includes particular steps of 1),acquiring a gully with the length of 100-200 meters and a gully-to-bed ratio of 300-700%o; 2), constructing the two gully side protection ridges; 3), laying straw biochar on the biochar zone on a land between ridges; 4), uniformly spraying SH series sand fixing materials on the sand fixing coating; 5), cultivating vegetation on the ridges of the two gully side protection ridges according to 'pyramid' shapes; 6), planting two rows of shrubs in zones between the first gully side protection ridge and the second gully side protection ridge and uniformly sowing herbaceous plants below the shrubs;7), planting single-row shrubs between a gully edge and the first gully side protection ridge and planting vine planes in a cave-shaped manner. The two rows of shrubs planted in the zones between thefirst gully side protection ridge and the second gully side protection ridge at the step 6) are parallel to the two gully side protection ridges. The single-row shrubs planted between the gully edge and the first gully side protection ridge at the step 7) are adjacent to the side, which is close to the gully edge, of the first gully side protection ridge.

Yang Haijun

Papers

Sensors Applied for the Detection of Pesticides and Heavy Metals in Freshwaters

Impacts of pollution, sex, and tide on the time allocations to behaviours of Uca arcuata in mangroves.

Amphibians crossing channel ecological module

Management method for controlling erosion of gully sides in loess hilly regions