NiCu Alloy Nanoparticle-Loaded Carbon Nanofibers for Phenolic Biosensor Applications

Versatile Carbon Nanofiber-Based Sensors

Carbon nanofibers (CNFs) display colossal potential in different fields like energy, catalysis, biomedicine, sensing, and environmental science. CNFs have revealed extensive uses in various sensing platforms due to their distinctive structure, properties, function, and accessible surface functionalization capabilities. This review presents insight into various fabrication methods for CNFs like electrospinning, chemical vapor deposition, and template methods with merits and demerits of each technique. Also, we give a brief overview of CNF functionalization. Their unique physical and chemical properties make them promising candidates for the sensor applications. This review offers detailed discussion of sensing applications (strain sensor, biosensor, small molecule detection, food preservative detection, toxicity biomarker detection, and gas sensor). Various sensing applications of CNF like human motion monitoring and energy storage and conversion are discussed in brief. The challenges and obstacles associated with CNFs for futuristic applications are discussed. This review will be helpful for readers to understand the different fabrication methods and explore various applications of the versatile CNFs.

Electrospun Fe3O4-Sn@Carbon Nanofibers Composite as Efficient Anode Material for Li-Ion Batteries

Nanoscale Fe₃O₄-Sn@CNFs was prepared by loading Fe₃O₄ and Sn nanoparticles onto CNFs synthesized via electrostatic spinning and subsequent thermal treatment by solvothermal reaction, and were used as anode materials for lithium-ion batteries. The prepared anode delivers an excellent reversible specific capacity of 1120 mAh·g^-1 at a current density of 100 mA·g^-1 at the 50th cycle. The recovery rate of the specific capacity (99%) proves the better cycle stability. Fe₃O₄ nanoparticles are uniformly dispersed on the surface of nanofibers with high density, effectively increasing the electrochemical reaction sites, and improving the electrochemical performance of the active material. The rate and cycling performance of the fabricated electrodes were significantly improved because of Sn and Fe₃O₄ loading on CNFs with high electrical conductivity and elasticity.

Development of a Novel Electrochemical Biosensor Based on Carbon Nanofibers-Cobalt Phthalocyanine-Laccase for the Detection of p-Coumaric Acid in Phytoproducts

The present paper developed a new enzymatic biosensor whose support is a screen-printed electrode based on carbon nanofibers modified with cobalt phthalocyanine and laccase (CNF-CoPc-Lac/SPE) to determine the p-coumaric acid (PCA) content by cyclic voltammetry and square wave voltammetry. Sensor modification was achieved by the casting and cross-linking technique, using glutaraldehyde as a reticulation agent. The biosensor’s response showed the PCA redox processes in a very stable and sensitive manner. The calibration curve was developed for the concentration range of p-coumaric acid of 0.1–202.5 μM, using cyclic voltammetry and chronoamperometry. The biosensor yielded optimal results for the linearity range 0.4–6.4 μM and stood out by low LOD and LOQ values, i.e., 4.83 × 10⁻⁷ M and 1.61 × 10⁻⁶ M, respectively. PCA was successfully determined in three phytoproducts of complex composition. The results obtained by the voltammetric method were compared to the ones obtained by the FTIR method. The amount of p-coumaric acid determined by means of CNF-CoPc-Lac/SPE was close to the one obtained by the standard spectrometric method.

A comprehensive review summarizing the recent biomedical applications of functionalized carbon nanofibers

Since the discovery and fabrication of carbon nanofibers (CNFs) over a decade ago, scientists foster to discover novel myriad potential applications for this material in both biomedicine and industry. The unique economic viability, mechanical, electrical, optical, thermal, and structural properties of CNFs led to their rapid emergence. CNFs become an artificial intelligence platform for different uses, including a wide range of biomedical applications. Furthermore, CNFs have exceptionally large surface areas that make them flexible for tailoring and functionalization on demand. This review highlights the recent progress and achievements of CNFs in a wide range of biomedical fields, including cancer therapy, biosensing, tissue engineering, and wound dressing. Besides the synthetic techniques of CNFs, their potential toxicity and limitations, as biomaterials in real clinical settings, will be presented. This review discusses CNF's future investigations in other biomedical fields, including gene delivery and bioimaging and CNFs risk assessment.

Recent developments in the sonoelectrochemical synthesis of nanomaterials

In recent years, the synthesis and use of nanoparticles have been of special interest among the scientific communities due to their unique properties and applications in various advanced technologies. The production of these materials at industrial scale can be difficult to achieve due to high cost, intense labour and use of hazardous solvents that are often required by traditional chemical synthetic methods. Sonoelectrochemistry is a hybrid technique that combines ultrasound and electrochemistry in a specially designed electrochemical setup. This technique can be used to produce nanomaterials with controlled sizes and shapes. The production of nanoparticles by sonoelectrochemistry as a technique offers many advantages: (i) a great enhancement in mass transport near the electrode, thereby altering the rate, and sometimes the mechanism of the electrochemical reactions, (ii) a modification of surface morphology through cavitation jets at the electrode-electrolyte interface, usually causing an increase of the surface area and (iii) a thinning of the electrode diffusion layer thickness and therefore ion depletion. The scalability of sonoelectrochemistry for producing nanomaterials at industrial scale is also very plausible due to its "one-pot" synthetic approach. Recent advancements in sonoelectrochemistry for producing various types of nanomaterials are briefly reviewed in this article. It is with hope that the presentation of these studies therein can generate more interest in the field to "catalyze" future investigations in novel nanomaterial development and industrial scale-up studies.

Application of eukaryotic and prokaryotic laccases in biosensor and biofuel cells: recent advances and electrochemical aspects

Laccases exhibit a wide range of applications, especially in the electrochemical field, where they are regarded as a potential biotic component. Laccase-based biosensors have immense practical applications in the food, environmental, and medical fields. The application of laccases as biocathodes in enzymatic biofuel cells has promising potential in the preparation of implantable equipment. Extensive studies have been directed towards the potential role of fungal laccases as biotic components of electrochemical equipment. In contrast, the potential of prokaryotic laccases in electrochemistry has been not fully understood. However, there has been recent and rapid progress in the discovery and characterization of new types of prokaryotic laccases. In this review, we have comprehensively discussed the application of different sources of laccases as a biocatalytic component in various fields of application. Further, we described the potential of different types of laccases in bioelectrochemical applications.

Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing

The integration of different noble metal nanostructures, which exhibit desirable plasmonic and/or electrocatalytic properties, with electrospun polymer nanofibers, which display unique mechanical and thermodynamic properties, yields novel hybrid nanoscale systems of synergistic properties and functions. This review summarizes recent advances on how to incorporate noble metal nanoparticles into electrospun polymer nanofibers and illustrates how such integration paves the way towards chemical sensing applications with improved sensitivity, stability, flexibility, compatibility, and selectivity. It is expected that further development of this field will eventually make a wide impact on many areas of research.

Hydrocalumite Thin Films for Polyphenol Biosensor Elaboration

Hybrid thin films based on Hydrocalumite (Ca₂AlCl layered double hydroxide LDH) and tyrosinaseenzyme have been used for the elaboration of a high sensitive amperometric biosensor detecting polyphenols extracted from green tea. Structural properties of LDH nanomaterials were characterized by X-ray powder diffraction and Infra-Red spectroscopy, confirming its crystalline phase and chemical composition. Ca₂AlCl-LDHs-thin films were deposited by spin-coating, and studied by atomic force microscopy to obtain information about the surface morphology of this host matrix before and after enzyme's immobilization. Electrochemical study using cyclic voltammetry and chronoamperometry shows good performances of the built-in biosensor with a high sensitivity for polyphenols concentrations ranging from 24 pM to and a limit of detection of 1.2 pM.

Detection of Copper(II) Ions Using Glycine on Hydrazine-Adsorbed Gold Nanoparticles via Raman Spectroscopy

A facile, selective, and sensitive detection method for the Cu²⁺ ions in environmental and biological solutions has been newly developed by observing the unique CN stretching peaks at ~2108 cm⁻¹ upon the dissociative adsorption of glycine (GLY) in hydrazine buffer on gold nanoparticles (AuNPs). The relative abundance of Cu species on AuNPs was identified from X-ray photoelectron spectroscopy analysis. UV-Vis spectra also indicated that the Au particles aggregated to result in the color change owing to the destabilization induced by the GLY-Cu²⁺ complex. The CN stretching band at ~2108 cm⁻¹ could be observed to indicate the formation of the CN species from GLY on the hydrazine-covered AuNP surfaces. The other ions of Fe³⁺, Fe²⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Zn²⁺, Cr³⁺, Co²⁺, Cd²⁺, Pb²⁺, Ca²⁺, NH₄⁺, Na⁺, and K⁺ at high concentrations of 50 µM did not produce such spectral changes. The detection limit based on the CN band for the determination of the Cu²⁺ ion could be estimated to be as low as 500 nM in distilled water and 1 µM in river water, respectively. We attempted to apply our method to estimate intracellular ion detection in cancer cells for more practical purposes.

Recent advances in electrospun metal-oxide nanofiber based interfaces for electrochemical biosensing

Synthesis of various electrospun metal-oxide nanofibers and their application towards electrochemical enzymatic and enzyme-free biosensor platforms has been critically discussed.