Gold-decorated magnetic nanoparticles modified with hairpin-shaped DNA for fluorometric discrimination of single-base mismatch DNA

The Recent Applications of Magnetic Nanoparticles in Biomedical Fields

Magnetic nanoparticles (MNPs) have found extensive application in the biomedical domain due to their enhanced biocompatibility, minimal toxicity, and strong magnetic responsiveness. MNPs exhibit great potential as nanomaterials in various biomedical applications, including disease detection and cancer therapy. Typically, MNPs consist of a magnetic core surrounded by surface modification coatings, such as inorganic materials, organic molecules, and polymers, forming a nucleoshell structure that mitigates nanoparticle agglomeration and enhances targeting capabilities. Consequently, MNPs exhibit magnetic responsiveness in vivo for transportation and therapeutic effects, such as enhancing medical imaging resolution and localized heating at the site of injury. MNPs are utilized for specimen purification through targeted binding and magnetic separation in vitro, thereby optimizing efficiency and expediting the process. This review delves into the distinctive functional characteristics of MNPs as well as the diverse bioactive molecules employed in their surface coatings and their corresponding functionalities. Additionally, the advancement of MNPs in various applications is outlined. Additionally, we discuss the advancements of magnetic nanoparticles in medical imaging, disease treatment, and in vitro assays, and we anticipate the future development prospects and obstacles in this field. The objective is to furnish readers with a thorough comprehension of the recent practical utilization of MNPs in biomedical disciplines.

Polymer-Coated Magnetite Nanoparticles for Protein Immobilization

Since their discovery, magnetic nanoparticles (MNPs) have become materials with great potential, especially considering the applications of biomedical sciences. A series of works on the preparation, characterization, and application of MNPs has shown that the biological activity of such materials depends on their size, shape, core, and shell nature. Some of the most commonly used MNPs are those based on a magnetite core. On the other hand, synthetic biopolymers are used as a protective surface coating for these nanoparticles. This review describes the advances in the field of polymer-coated MNPs for protein immobilization over the past decade. General methods of MNP preparation and protein immobilization are presented. The most extensive section of this article discusses the latest work on the use of polymer-coated MNPs for the physical and chemical immobilization of three types of proteins: enzymes, antibodies, and serum proteins. Where possible, the effectiveness of the immobilization and the activity and use of the immobilized protein are reported. Finally, the information available in the peer-reviewed literature and the application perspectives for the MNP-immobilized protein systems are summarized as well.

A peptide nucleic acid-regulated fluorescence resonance energy transfer DNA assay based on the use of carbon dots and gold nanoparticles

A convenient fluorometric method was developed for specific determination of DNA based on peptide nuclei acid (PNA)-regulated fluorescence resonance energy transfer (FRET) between carbon dots (CDs) and gold nanoparticles (AuNPs). In this system, CDs that display lake blue fluorescence with excitation/emission maxima at 345/445 nm were used as fluorometric reporter, while AuNPs were used as fluorescence nanoquencher. A neutral PNA probe, which is designed to recognize the target DNA, was used as a coagulant to control the dispersion and aggregation of AuNPs. Without DNA, PNA can induce immediate AuNP aggregation, thus leading to the recovery of the FRET-quenched fluorescence emission of CDs. However, the addition of the complementary target DNA can protect AuNPs from being aggregated due to the formation of DNA/PNA complexes, which subsequently produces a high fluorescence quenching efficiency of CDs by dispersed AuNPs. Under optimized conditions, quantitative evaluation of DNA was achieved in a linear range of 5-100 nM with a detection limit of 0.21 nM. This method exhibited an excellent specificity towards fully matched DNA. In addition, the application of this assay for sensitive determination of DNA in cell lysate demonstrates its potential for bioanalysis and biodetection. Graphical abstract A simple fluorometric biosensor for specific detection of DNA was developed based on peptide nuclei acid (PNA)-regulated fluorescence resonance energy transfer (FRET) between carbon dots (CDs) and gold nanoparticles (AuNPs).

Synthesis, Properties and Applications of Magnetic Nanoparticles and Nanowires—A Brief Introduction

Magnetic nanoparticles and magnetic nano-species of complex topology (e.g., nanorods, nanowires, nanotubes, etc.) are overviewed briefly in the paper, mostly giving attention to the synthetic details and particle composition (e.g., core-shell structures made of different materials). Some aspects related to applications of magnetic nano-species are briefly discussed. While not being a comprehensive review, the paper offers a large collection of references, particularly useful for newcomers in the research area.

Arabidopsis thaliana ITS sequence-specific DNA extraction by ion-tagged oligonucleotides coupled with a magnetic ionic liquid

This study reports a follow-up investigation on the capture of specific DNA sequences using ion-tagged oligonucleotides (ITOs) and magnetic ionic liquids (MIL). Five allylimidazolium salts bearing octyl substituents ([AOIM⁺]-ITOs) were used for the selective extraction of the internal transcribed spacer region (ITS) from Arabidopsis thaliana. In this work, the ability of the [AOIM⁺]-ITOs to enhance the extraction of longer target sequences (~ 700 bp) of plant origin was shown. Moreover, the independence of the probe binding position and the importance of complementarity to the target region for the extraction performance were demonstrated. To test the specificity of the ITOs, the same experiments were performed using the ITS region from another plant species, with a lower target capture for the probes which were specific for the A. thaliana sequence. Finally, extraction in the presence of interferences (heterogenous DNA, primary and secondary metabolites, proteins) provided interesting and insightful results. This work illustrates the feasibility and versatility of these probes when coupled to MILs for rapid, cost-effective, and environmentally sensitive sample preparation in the extraction of specific target sequences from different origins. Graphical abstract.