Folic Acid-Modified Cerium-Doped Carbon Dots as Photoluminescence Sensors for Cancer Cells Identification and Fe(III) Detection

Tb doped carbon dots as a platform for fluorescence ratiometric and colorimetric sensor for deferasirox

Tb doped carbon dots (Tb-CDs) were synthesized by a simple hydrothermal method and the existence of Tb in the obtained CDs was confirmed by the several characterization methods. Tb-CDs were exploited to design a ratiometric fluorescence sensor for deferasirox (DFX) assay. CDs and Tb acted as reference and sensing probs in the sensor. In the presence of DFX, the fluorescence intensity of CDs remained unchanged, while Tb emission increased. The fluorescence ratio of Tb to CDs was proportional to the DFX concentration at the range of 0.1 to 2.5 µM. Additionally, the fluorescence color altered from blue (CDs emission) to green (Tb emission) with increasing DFX concentration. We employed this color variation to establish a smartphone based sensor for the DFX detection. The linear range of established sensor was 0.5-15 µM. The detection limit (3S) for the ratiometric and smartphone based sensor was calculated to be 0.08 and 0.4 µM, respectively. Both sensors were applied to measure DFX in human serum samples with satisfactory results.

Beyond traditional methods: nanomaterials pave the way for precise nutrient detection in nutritionally fortified foods

Detecting trace elements in nutritionally fortified foods is essential for safeguarding public health, as these micronutrients play a critical role in various biological processes, including enzyme functionality, cellular metabolism, and the structural integrity of macromolecules; however, current analytical methods are often limited by high operational costs, complex sample preparation, and the requirement for specialized technical expertise. This review highlights the transformative potential of nanotechnology in addressing these challenges, showcasing how nanomaterials enhance trace element detection through specific ligand recognition, oxidation-reduction reactions, adsorption, enzyme-like activities, and resonance energy transfer mechanisms. We discuss the integration of monodentate, bidentate, and polydentate ligands in nanomaterial-based detection systems to improve specificity and stability, and explore the implications of technologies such as surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS), fluorescence, electrochemical signal, and spectral signal for advancing detection capabilities. Incorporating nanomaterial-based detection systems with advanced data processing technologies and portable inspection equipment is anticipated to enhance analytical capabilities, paving the way for real-time monitoring that fortifies food safety protocols, ensuring the quality and safety of fortified foods and ultimately contributing to improved public health outcomes.

Fluorescent carbon dots for discriminating cell types: a review

Carbon dots (CDs) are quasi-spherical carbon nanoparticles with excellent photoluminescence, good biocompatibility, favorable photostability, and easily modifiable surfaces. CDs, serving as fluorescent probes, have emerged as an ideal tool for cellular differentiation owing to their outstanding luminescence performance and tunable surface properties. In this review, we summarize the recent research progress with CDs in the differentiation of cancer/normal cells, Gram-positive/Gram-negative bacteria, and live/dead cells, as well as the cellular differences used for differentiation. Additionally, we summarize the preparation methods, raw materials, and properties of the CDs used for cell discrimination. The differentiation mechanisms and the advantages or limitations of the differentiation methods are also introduced. Finally, we propose several research challenges in this field and future research directions that require extensive investigation. It is hoped that this review will help researchers in the design of new CDs as ideal fluorescent probes for realizing diverse cell differentiation applications.

Carbon Dots based Tissue Equivalent Dosimeter as an Ionizing Radiation Sensor

This work explores the potential of carbon dots as a fluorescent probe in the determination of heavy ions and as an electrochemical biosensor. It also discusses how carbon dots can be introduced into the Fricke solution to potentially serve as an ionizing radiation sensor. The study presents a novel tissue equivalent dosimeter carbon dots-based as an ionizing radiation sensor. The methodology for the synthesis of Nitrogen-doped Carbon Dots N-CDs and the characterization of the material are described. The results show that the N-CDs have a high sensitivity to ionizing radiation and can be used as a dosimeter for radiation detection. The study also discusses the limitations and challenges of using carbon dots as a dosimeter for ionizing radiation. Overall, this study provides valuable insights into the potential applications of carbon dots in different fields and highlights the importance of further research in this area.

Efficient Chlorostannate Modification of Magnetite Nanoparticles for Their Biofunctionalization

Magnetite nanoparticles (MNPs) are highly favored materials for a wide range of applications, from smart composite materials and biosensors to targeted drug delivery. These multifunctional applications typically require the biofunctional coating of MNPs that involves various conjugation techniques to form stable MNP-biomolecule complexes. In this study, a cost-effective method is developed for the chlorostannate modification of MNP surfaces that provides efficient one-step conjugation with biomolecules. The proposed method was validated using MNPs obtained via an optimized co-precipitation technique that included the use of degassed water, argon atmosphere, and the pre-filtering of FeCl2 and FeCl3 solutions followed by MNP surface modification using stannous chloride. The resulting chlorostannated nanoparticles were comprehensively characterized, and their efficiency was compared with both carboxylate-modified and unmodified MNPs. The biorecognition performance of MNPs was verified via magnetic immunochromatography. Mouse monoclonal antibodies to folic acid served as model biomolecules conjugated with the MNP to produce nanobioconjugates, while folic acid-gelatin conjugates were immobilized on the test lines of immunochromatography lateral flow test strips. The specific trapping of the obtained nanobioconjugates via antibody-antigen interactions was registered via the highly sensitive magnetic particle quantification technique. The developed chlorostannate modification of MNPs is a versatile, rapid, and convenient tool for creating multifunctional nanobioconjugates with applications that span in vitro diagnostics, magnetic separation, and potential in vivo uses.

A review of innovative electrochemical strategies for bioactive molecule detection and cell imaging: Current advances and challenges

Cellular heterogeneity poses a major challenge for tumor theranostics, requiring high-resolution intercellular bioanalysis strategies. Over the past decades, the advantages of electrochemical analysis, such as high sensitivity, good spatio-temporal resolution, and ease of use, have made it the preferred method to uncover cellular differences. To inspire more creative research, herein, we highlight seminal works in electrochemical techniques for biomolecule analysis and bioimaging. Specifically, micro/nano-electrode-based electrochemical techniques enable real-time quantitative analysis of electroactive substances relevant to life processes in the micro-nanostructure of cells and tissues. Nanopore-based technique plays a vital role in biosensing by utilizing nanoscale pores to achieve high-precision detection and analysis of biomolecules with exceptional sensitivity and single-molecule resolution. Electrochemiluminescence (ECL) technology is utilized for real-time monitoring of the behavior and features of individual cancer cells, enabling observation of their dynamic processes due to its capability of providing high-resolution and highly sensitive bioimaging of cells. Particularly, scanning electrochemical microscopy (SECM) and scanning ion conductance microscopy (SICM) which are widely used in real-time observation of cell surface biological processes and three-dimensional imaging of micro-nano structures, such as metabolic activity, ion channel activity, and cell morphology are introduced in this review. Furthermore, the expansion of the scope of cellular electrochemistry research by innovative functionalized electrodes and electrochemical imaging models and strategies to address future challenges and potential applications is also discussed in this review.