Application of Fe3O4 nanoparticles functionalized carbon nanotubes for electrochemical sensing of DNA hybridization

Advances in magnetic field-assisted electrolyte's physicochemical properties and electrokinetic parameters: A case study on the response ability of chloramphenicol on Fe3O4@carbon spheres-based electrochemical nanosensor

Despite the utilization of external magnetic field (MF) in promoting the intrinsic unique features of magnetic nanomaterials in many different applications has been reported, however the origin of MF-dependent electrochemical behaviors as well as the electrochemical response of analytes at the electrode in sensor applications is still not clear. In this report, the influence of MF on the electrolyte's physicochemical properties (polarization, mass transport, charge/electron transfer) and electrode's properties (conductivity, morphology, surface area, interaction, adsorption capability, electrocatalytic ability) was thoroughly investigated. Herein, the working electrode surface was modified with carbon spheres (CSs), magnetic nanoparticles (Fe₃O₄NPs), and their nanocomposites (Fe₃O₄@CSs), respectively. Then, they were directly used to enhance the electrochemical characteristics and response-ability of chloramphenicol (CAP). More interestingly, a series of various kinetic parameters related to the diffusion-controlled process of K₃[Fe(CN)₆]/K₄[Fe(CN)₆)] and the adsorption-controlled process of CAP were calculated at the bare electrode and the modified electrodes with and without the presence of MF. These parameters not only exhibit the crucial role of the modification of electrode surface with the proposed materials but also show positive impacts of the presence of external MF. Besides, the mechanism and hypothesis for the enhancements were proposed and discussed in detail, further demonstrating the development potential of using Fe₃O₄@CS nanocomposites with MF assistant for advanced energy, environmental, and sensor related-applications.

Recent Development of Graphene Based Electrochemical Sensor for Detecting Hematological Malignancies-Associated Biomarkers: A Mini-Review

Hematologic malignancies are a group of malignant diseases of the hematologic system that seriously endanger human health, mainly involving bone marrow, blood and lymphatic tissues. However, among the available treatments for malignant hematologic diseases, low detection rates and high recurrence rates are major problems in the treatment process. The quantitative detection of hematologic malignancies-related biomarkers is the key to refine the pathological typing of the disease to implement targeted therapy and thus improve the prognosis. In recent years, bioelectrochemical methods for tumor cell and blood detection have attracted the attention of an increasing number of scientists. The development of biosensor technology, nanotechnology, probe technology, and lab-on-a-chip technology has greatly facilitated the development of bioelectrochemical studies of cells, especially for blood and cell-based assays and drug resistance differentiation. To improve the sensitivity of detection, graphene is often used in the design of electrochemical sensors. This mini-review provides an overview of the types of hematological malignancies-associated biomarkers and their detection based on graphene assisted electrochemical sensors.

Nitrogen doped chiral carbonaceous nanotube for ultrasensitive DNA direct electrochemistry, DNA hybridization and damage study

In the interest of developing novel electrocatalyst for high performance DNA biosensing, with distinctive chiral double helix nanostructure, nitrogen doped chiral carbonaceous nanotube (Chiral-CNT) was employed for ultrasensitive label-free DNA biosensing research. Chiral-CNT can quantitative detection of four DNA bases with high sensitivity and selectivity. Without any prehydrolysis and labeling process, direct electrochemistry of single-stranded DNA and double-stranded DNA, qualitative and quantitative detection of DNA hybridization (low detection limit: 0.0268 g L^-1) were realized. Moreover, sensitive detection of DNA damage induced by fenton reagent was also realized with low detection limit of 0.0350 mg mL^-1 and high sensitivity of 7.42 μA mg^-1 mL. The high biosensing performance attributes to the unique chiral structure of Chiral-CNT, leads to efficient interreaction between Chiral-CNT and DNA molecule.