scholarly journals Functionalized Electrospun Nanofibers as Colorimetric Sensory Probe for Mercury Detection: A Review

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4763 ◽  
Author(s):  
Brabu Balusamy ◽  
Anitha Senthamizhan ◽  
Tamer Uyar

Mercury is considered the most hazardous pollutant of aquatic resources; it exerts numerous adverse effects on environmental and human health. To date, significant progress has been made in employing a variety of nanomaterials for the colorimetric detection of mercury ions. Electrospun nanofibers exhibit several beneficial features, including a large surface area, porous nature, and easy functionalization; thus, providing several opportunities to encapsulate a variety of functional materials for sensing applications with enhanced sensitivity and selectivity, and a fast response. In this review, several examples of electrospun nanofiber-based sensing platforms devised by utilizing the two foremost approaches, namely, direct incorporation and surface decoration envisioned for detection of mercury ions are provided. We believe these examples provide sufficient evidence for the potential use and progress of electrospun nanofibers toward colorimetric sensing of mercury ions. Furthermore, the summary of the review is focused on providing an insight into the future directions of designing electrospun nanofiber-based, metal ion colorimetric sensors for practical applications.

The Analyst ◽  
2019 ◽  
Vol 144 (4) ◽  
pp. 1205-1209 ◽  
Author(s):  
Chi Zhang ◽  
Caiyun Kong ◽  
Qingyun Liu ◽  
Zhengbo Chen

We herein present a simple, low-cost, and ultrasensitive colorimetric sensing strategy for the detection of mercury ions (Hg2+) that takes advantage of the natural pore structure in rose petals to encapsulate gold nanoparticles (AuNPs).


Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2421 ◽  
Author(s):  
Brabu Balusamy ◽  
Anitha Senthamizhan ◽  
Tamer Uyar

The increasing heavy metal pollution in the aquatic ecosystem mainly driven by industrial activities has raised severe concerns over human and environmental health that apparently necessitate the design and development of ideal strategies for the effective monitoring of heavy metals. In this regard, colorimetric detection provides excellent opportunities for the easy monitoring of heavy metal ions, and especially, corresponding solid-state sensors enable potential opportunities for their applicability in real-world monitoring. As a result of the significant interest originating from their simplicity, exceptional characteristics, and applicability, the electrospun nanofiber-based colorimetric detection of heavy metal ions has undergone radical developments in the recent decade. This review illustrates the range of various approaches and functional molecules employed in the fabrication of electrospun nanofibers intended for the colorimetric detection of various metal ions in water. We highlight relevant investigations on the fabrication of functionalized electrospun nanofibers encompassing different approaches and functional molecules along with their sensing performance. Furthermore, we discuss upcoming prospectus and future opportunities in the exploration of designing electrospun nanofiber-based colorimetric sensors for real-world applications.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pei Li ◽  
Sang Mo Lee ◽  
Hyo Yong Kim ◽  
Soohyun Kim ◽  
Steve Park ◽  
...  

AbstractWe herein described a rapid, sensitive, and selective colorimetric sensing platform for biothiols in human serum, which relies on the dual functions of biothiols as anti-etching and aggregating agent for silver nanoprisms (AgNPRs). In principle, the target biothiols that bind to the surface of AgNPRs through Ag–S covalent interactions protect the AgNPRs from being etched by chloride ion (Cl−) in human serum, thus exhibiting the blue/purple color that is indicative of AgNPRs. On the other hand, the color of AgNPRs turned to yellow in the absence of biothiols or the presence of non-sulfur-containing amino acids, indicating the formation of small silver nanoparticles (AgNPs). Importantly, we found that individual biothiols (Hcy, Cys, and GSH) exert not only the anti-etching effect, but also the aggregating effect on AgNPRs, which can be modulated by simply tuning the pH conditions, and this consequently allows for the discriminative detection of each biothiol. Based on this simple and cost-effective strategy, we successfully determined the Hcy, Cys, and GSH in human serum with high sensitivity and selectivity within 10 min, demonstrating the diagnostic capability and potential in practical applications.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4043
Author(s):  
Ádám Golcs ◽  
Korinna Kovács ◽  
Panna Vezse ◽  
Tünde Tóth ◽  
Péter Huszthy

Acridino-diaza-20-crown-6 ether derivatives as new turn-on type fluorescent chemosensors with an excellent functionality and photophysical properties have been designed and synthesized for metal ion-selective optochemical sensing applications. Spectroscopic studies revealed that in an acetonitrile-based semi-aqueous medium, the sensor molecules exhibited a remarkable fluorescence enhancement with high sensitivity only toward Zn2+, Al3+ and Bi3+, among 23 different metal ions. Studies on complexation showed a great coordinating ability of logK > 4.7 with a 1:1 complex stoichiometry in each case. The detection limits were found to be from 59 nM to micromoles. The new ionophores enabled an optical response without being affected either by the pH in the range of 5.5–7.5, or the presence of various anions or competing metal ions. Varying the N-substituents of the new host-backbone provides diverse opportunities in both immobilization and practical applications without influencing the molecular recognition abilities.


2019 ◽  
Vol 9 (2) ◽  
pp. 151-162
Author(s):  
Shveta Acharya ◽  
Arun Kumar Sharma

Background: The metal ions play a vital role in a large number of widely differing biological processes. Some of these processes are quite specific in their metal ion requirements. In that only certain metal ions, in specific oxidation states, can full fill the necessary catalytic or structural requirement, while other processes are much less specific. Objective: In this paper we report the binding of Mn (II), Ni (II) and Co (II) with albumin are reported employing spectrophotometric and pH metric method. In order to distinguish between ionic and colloidal linking, the binding of metal by using pH metric and viscometric methods and the result are discussed in terms of electrovalent and coordinate bonding. Methods: The binding of Ni+2, Co+2 and Mn+2 ions have been studied with egg protein at different pH values and temperatures by the spectrometric technique. Results: The binding data were found to be pH and temperature dependent. The intrinsic association constants (k) and the number of binding sites (n) were calculated from Scatchard plots and found to be at the maximum at lower pH and at lower temperatures. Therefore, a lower temperature and lower pH offered more sites in the protein molecule for interaction with these metal ions. Statistical effects seem to be more significant at lower Ni+2, Co+2 and Mn+2 ions concentrations, while at higher concentrations electrostatic effects and heterogeneity of sites are more significant. Conclusion: The pH metric as well as viscometric data provided sufficient evidence about the linking of cobalt, nickel and manganese ions with the nitrogen groups of albumin. From the nature and height of curves in the three cases it may be concluded that nickel ions bound strongly while the cobalt ions bound weakly.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jin Yeong Song ◽  
Hyun Il Ryu ◽  
Jeong Myeong Lee ◽  
Seong Hwan Bae ◽  
Jae Woo Lee ◽  
...  

AbstractElectrospinning is a common and versatile process to produce nanofibers and deposit them on a collector as a two-dimensional nanofiber mat or a three-dimensional (3D) macroscopic arrangement. However, 3D electroconductive collectors with complex geometries, including protruded, curved, and recessed regions, generally caused hampering of a conformal deposition and incomplete covering of electrospun nanofibers. In this study, we suggested a conformal fabrication of an electrospun nanofiber mat on a 3D ear cartilage-shaped hydrogel collector based on hydrogel-assisted electrospinning. To relieve the influence of the complex geometries, we flattened the protruded parts of the 3D ear cartilage-shaped hydrogel collector by exploiting the flexibility of the hydrogel. We found that the suggested fabrication technique could significantly decrease an unevenly focused electric field, caused by the complex geometries of the 3D collector, by alleviating the standard deviation by more than 70% through numerical simulation. Furthermore, it was experimentally confirmed that an electrospun nanofiber mat conformally covered the flattened hydrogel collector with a uniform thickness, which was not achieved with the original hydrogel collector. Given that this study established the conformal electrospinning technique on 3D electroconductive collectors, it will contribute to various studies related to electrospinning, including tissue engineering, drug/cell delivery, environmental filter, and clothing.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1667
Author(s):  
Mikhail Karushev

Fast and reversible cobalt-centered redox reactions in metallopolymers are the key to using these materials in energy storage, electrocatalytic, and sensing applications. Metal-centered electrochemical activity can be enhanced via redox matching of the conjugated organic backbone and cobalt centers. In this study, we present a novel approach to redox matching via modification of the cobalt coordination site: a conductive electrochemically active polymer was electro-synthesized from [Co(Amben)] complex (Amben = N,N′-bis(o-aminobenzylidene)ethylenediamine) for the first time. The poly-[Co(Amben)] films were investigated by cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM), in situ UV‑vis-NIR spectroelectrochemistry, and in situ conductance measurements between −0.9 and 1.3 V vs. Ag/Ag+. The polymer displayed multistep redox processes involving reversible transfer of the total of 1.25 electrons per repeat unit. The findings indicate consecutive formation of three redox states during reversible electrochemical oxidation of the polymer film, which were identified as benzidine radical cations, Co(III) ions, and benzidine di-cations. The Co(II)/Co(III) redox switching is retained in the thick polymer films because it occurs at potentials of high polymer conductivity due to the optimum redox matching of the Co(II)/Co(III) redox pair with the organic conjugated backbone. It makes poly-[Co(Amben)] suitable for various practical applications based on cobalt-mediated redox reactions.


2021 ◽  
Vol 22 (12) ◽  
pp. 6357
Author(s):  
Kinga Halicka ◽  
Joanna Cabaj

Sensors and biosensors have found applications in many areas, e.g., in medicine and clinical diagnostics, or in environmental monitoring. To expand this field, nanotechnology has been employed in the construction of sensing platforms. Because of their properties, such as high surface area to volume ratio, nanofibers (NFs) have been studied and used to develop sensors with higher loading capacity, better sensitivity, and faster response time. They also allow to miniaturize designed platforms. One of the most commonly used techniques of the fabrication of NFs is electrospinning. Electrospun NFs can be used in different types of sensors and biosensors. This review presents recent studies concerning electrospun nanofiber-based electrochemical and optical sensing platforms for the detection of various medically and environmentally relevant compounds, including glucose, drugs, microorganisms, and toxic metal ions.


Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 204
Author(s):  
Yanyan Cheng ◽  
Ling Liang ◽  
Fanggui Ye ◽  
Shulin Zhao

Metal–organic framework (MOF) nanozymes, as emerging members of the nanozymes, have received more and more attention due to their composition and structural characteristics. In this work, we report that mixed-valence state Ce-MOF (MVCM) has intrinsic haloperoxidase-mimicking activity. MVCM was synthesized by partial oxidation method using Ce-MOF as a precursor. In the presence of H2O2 and Br−, MVCM can catalyze oxidative bromination of chromogenic substrate phenol red (PR) to produce the blue product bromophenol blue (Br4PR), showing good haloperoxidase-like activity. Because of the special chromogenic substrate, we constructed a ratiometric colorimetric-sensing platform by detecting the absorbance of the MVCM-(PR, Br−) system at wavelengths of 590 and 430, for quantifying H2O2, where the detection limit of the H2O2 is 3.25 μM. In addition, the haloperoxidase-mimicking mechanism of the MVCM is proposed. Moreover, through enzyme kinetics monitoring, the Km (H2O2 and NH4Br) of the MVCM is lower than that of cerium oxide nanomaterials, indicating that the MVCM has a stronger binding affinity for H2O2 and NH4Br than other materials. This work provides more application prospects for the development of nanozymes in the field of biosensors in the future.


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