electrochemical technique
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2021 ◽  
Author(s):  
Alexander Vaneev ◽  
Petr Gorelkin ◽  
Olga Krasnovskaya ◽  
Roman Akasov ◽  
Daniil Spector ◽  
...  

The biodistribution of chemotherapy compounds within tumor tissue is one of the main challenges in the development of antineoplastic drugs, and novel techniques for simple, non-expensive, sensitive, and selective detection of various analytes in tumors are of great importance. In this paper we propose the use of platinized carbon nanoelectrodes (PtNE) for electrochemical detection of platinum-based drugs in various biological models, including single cells and tumor spheroids in vitro, and inside solid tumors in vivo. We have demonstrated quantitative direct detection of Pt(II) in breast adenocarcinoma MCF-7 cells treated with cisplatin and cisplatin-based DNP prodrug. To realize the potential of this technique in advanced tumor models, we measured Pt(II) in 3D tumor spheroids in vitro and tumor-bearing mice in vivo. The concentration gradient of Pt (II) species correlated with the distance from the sample surface in MCF-7 tumor spheroids. We then performed detection of Pt(II) species in tumor-bearing mice treated intravenously with cisplatin and DNP. We found that there was deeper penetration of DNP in comparison to cisplatin. This research demonstrates a novel minimally invasive, real-time electrochemical technique for the study of platinum-based drugs.


Author(s):  
Moriah E Weese-Myers ◽  
Ashley E Ross

Abstract Small molecules and signaling peptides are extensively involved in controlling basic brain function. While classical neurotransmitters can be detected with a variety of techniques, methods for measurement of rapidly-released neuropeptides remain underdeveloped. Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique often used for subsecond detection of small molecule neurotransmitters, in vivo. A few peptides have been detected with FSCV; however, a detailed analysis of the electrochemical signature of all electroactive amino acids with FSCV has not been fully investigated. Because the mechanisms, locations, and timescales for signaling peptide release in the brain are relatively unexplored, developing sensitive and selective tools capable of quantitating neuropeptide signaling is essential. To bridge this gap, we used FSCV to characterize the electroactive amino acids: cysteine, methionine, histidine, tryptophan, and tyrosine. We show that tyrosine, tryptophan, and histidine are easily oxidized on carbon fiber surfaces with FSCV, while detection of the sulfur-containing amino acids is more difficult. This study provides critical information for electrochemical waveform design and optimization for detection of peptides containing these amino acids.


2021 ◽  
pp. 1-22
Author(s):  
Qing Wang ◽  
Shuangshuang Xu ◽  
Xiaoting Xing ◽  
Ning Wang

Natural biological surfaces such as lotus leaves and water striders have micro- and nanostructures and low-surface-energy materials, possessing excellent superhydrophobicity. It has become an important research topic to construct bionic superhydrophobic surfaces and explore their functional applications. This paper reviews the research progress on the fabrication and applications of superhydrophobic surfaces with micro/nanostructures. The techniques used for fabricating superhydrophobic surfaces, including the template method, nano-imprinting technique, laser-treatment, plasma treatment, electrospinning technique, solution-chemical etching method, electrochemical technique, phase separation method and sol–gel process, were introduced. Also, the diverse functional applications of superhydrophobic surfaces such as self-cleaning, anti-icing, oil–water separation, anti-corrosion and drag reduction were summarised. It is believed that green fabrication will become the future development direction of superhydrophobic surfaces. Further exploration for the superhydrophobic surfaces with mechanical stability and durability will be expected to expand the application prospect and commercial value of superhydrophobic surfaces.


Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4162
Author(s):  
Eider A. Erazo ◽  
Martín Gómez ◽  
Leonardo Rios ◽  
Edgar J. Patiño ◽  
María T. Cortés ◽  
...  

The atomic layer deposition (ALD) of Al2O3 between perovskite and the hole transporting material (HTM) PEDOT:PSS has previously been shown to improve the efficiency of perovskite solar cells. However, the costs associated with this technique make it unaffordable. In this work, the deposition of an organic–inorganic PEDOT:PSS-Cl-Al2O3 bilayer is performed by a simple electrochemical technique with a final annealing step, and the performance of this material as HTM in inverted perovskite solar cells is studied. It was found that this material (PEDOT:PSS-Al2O3) improves the solar cell performance by the same mechanisms as Al2O3 obtained by ALD: formation of an additional energy barrier, perovskite passivation, and increase in the open-circuit voltage (Voc) due to suppressed recombination. As a result, the incorporation of the electrochemical Al2O3 increased the cell efficiency from 12.1% to 14.3%. Remarkably, this material led to higher steady-state power conversion efficiency, improving a recurring problem in solar cells.


2021 ◽  
Vol 12 (6) ◽  
pp. 7697-7714

Neonatal sepsis is a serious and potentially life-threatening condition and a major cause of higher mortality and morbidity in the infant population. At present, the available for neonatal sepsis detection is conventional microbial testing. However, this method has various constraints, including being expensive, requiring qualified individuals, large sample volume needed for testing, and time-consuming process. The emergence of biosensors facilitates advantages over these constraints. The presented work describes the development of an electrochemical biosensor detecting C-reactive protein, a biomarker for neonatal sepsis, utilizing molecularly imprinted polymer fabricated on an electrode surface. Gold-platinum bimetallic nanomaterials were coated on the screen-printed carbon electrode to enhance the sensor's surface area and catalytic property. The C-reactive protein imprinted polymer was then deposited on the surface of the electrode. Further, the electrochemical technique was applied to measure the response of the developed electrode. It was observed that the sensing matrix was able to detect C-reactive protein and can be operated in a wide detection range and exhibits a lower detection limit as 0.1 nM with higher sensitivity (0.14 μA/nM). The developed sensing platform can provide a user-friendly approach and rapid detection results.


2021 ◽  
Vol MA2021-02 (11) ◽  
pp. 1916-1916
Author(s):  
Maksim Bahdanchyk ◽  
Gianmaria Gasperini ◽  
Paolo Gronchi ◽  
Antonello Vicenzo

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6695
Author(s):  
Dirk Johannes De Beer ◽  
Trudi-Heleen Joubert

Impedance spectroscopy is a widely used electrochemical technique with a wide variety of applications. Many of these applications benefit from the additional accessibility provided by low-cost impedance devices. With this in mind, a low-cost impedance device was designed for a high performance-to-cost ratio. The performance of this analyzer was validated against a high-performance DropSens µStat-i 400s potentiostat by performing an application-based experiment. Nitrate detection provides a relevant experiment because of the importance of maintaining precise nitrate concentrations to mitigate the impact of nitrate fluctuations on the environment. Dissolved nitrate samples of different concentrations, in the range 3–1000 mg/L, were confirmed colorimetrically and measured with both instruments. A calibration curve of the real impedance matched a sigmoidal transfer, with a linear region for concentrations below 10 mg/L. The device under investigation exhibited an average magnitude error of 1.28% and an average phase error of 0.96∘ relative to the high-performance standard, which validates the performance of the low-cost device. A cost analysis is presented that highlights some of the complexities of cost comparisons.


Author(s):  
O.V. Pavlyuk ◽  
◽  
Yu.I. Slyvka ◽  
N.T. Pokhodylo ◽  
M.G. Mys'kiv

By means of the alternating current electrochemical technique and starting from copper wire electrodes in propanol solution of corresponding ligand and copper(II) nitrate, novel copper(I) -complex [Cu2(C12H14SN4)2(NO3)2] (1) has been obtained and X-ray structurally investigated: sp. gr. , a=7.352(3) Å, b=8.269(3) Å, c=12.723(4) Å, =82.08(3)0, =82.74(3)0, =88.37(3)0, V=759.9(5) Å3, Z=2, dcalc=1.625 g cm–3, (CuK)=3.502 mm–1, max=67.960, 4119 measured reflections, 1248 used reflections, 201 refined parameters, R(F2)=0.0915, S=0.95. The trigonal-pyramidal copper(I) coordination environment consists of nitrogen atom and allylic group of ligand, and of two oxygen atoms from crystallographically distinct nitrate anions. Due to a bridging function of oxygen atoms of nitrate anions, two metal-containing polyhedra are connected into {Cu2L2(NO3)2} topological units which are additionally stabilized by noncovalent interaction CuO(2). Comparatively weak hydrogen bonds C–HO exist in the crystal structure of [Cu2(C12H14SN4)2(NO3)2] (1).


Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3360
Author(s):  
Borys M. Gorelov ◽  
Oleksandr V. Mischanchuk ◽  
Nadia V. Sigareva ◽  
Sergey V. Shulga ◽  
Alla M. Gorb ◽  
...  

Multilayered graphene nanoplatelets (MLGs) were prepared from thermally expanded graphite flakes using an electrochemical technique. Morphological characterization of MLGs was performed using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Raman spectroscopy (RS), and the Brunauer–Emmett–Teller (BET) method. DGEBA-epoxy-based nanocomposites filled with synthesized MLGs were studied using Static Mechanical Loading (SML), Thermal Desorption Mass Spectroscopy (TDMS), Broad-Band Dielectric Spectroscopy (BDS), and Positron Annihilation Lifetime Spectroscopy (PALS). The mass loading of the MLGs in the nanocomposites was varied between 0.0, 0.1, 0.2, 0.5, and 1% in the case of the SML study and 0.0, 1.0, 2, and 5% for the other measurements. Enhancements in the compression strength and the Young’s modulus were obtained at extremely low loadings (C≤ 0.01%). An essential increase in thermal stability and a decrease in destruction activation energy were observed at C≤ 5%. Both the dielectric permittivity (ε1) and the dielectric loss factor (ε2) increased with increasing C over the entire frequency region tested (4 Hz–8 MHz). Increased ε2 is correlated with decreased free volume when increasing C. Physical mechanisms of MLG–epoxy interactions underlying the effects observed are discussed.


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