A graphene-based platform for fluorescent detection of SNPs

Recent Progress in Single-Nucleotide Polymorphism Biosensors

Single-nucleotide polymorphisms (SNPs), the most common form of genetic variation in the human genome, are the main cause of individual differences. Furthermore, such attractive genetic markers are emerging as important hallmarks in clinical diagnosis and treatment. A variety of destructive abnormalities, such as malignancy, cardiovascular disease, inherited metabolic disease, and autoimmune disease, are associated with single-nucleotide variants. Therefore, identification of SNPs is necessary for better understanding of the gene function and health of an individual. SNP detection with simple preparation and operational procedures, high affinity and specificity, and cost-effectiveness have been the key challenge for years. Although biosensing methods offer high specificity and sensitivity, as well, they suffer drawbacks, such as complicated designs, complicated optimization procedures, and the use of complicated chemistry designs and expensive reagents, as well as toxic chemical compounds, for signal detection and amplifications. This review aims to provide an overview on improvements for SNP biosensing based on fluorescent and electrochemical methods. Very recently, novel designs in each category have been presented in detail. Furthermore, detection limitations, advantages and disadvantages, and challenges have also been presented for each type.

Advanced Theranostic Strategies for Viral Hepatitis Using Carbon Nanostructures

There are several treatment protocols for acute viral hepatitis, and it is critical to recognize acute hepatitis in its earliest stages. Public health measures to control these infections also rely on rapid and accurate diagnosis. The diagnosis of viral hepatitis remains expensive, and there is no adequate public health infrastructure, while the virus is not well-controlled. New methods for screening and detecting viral hepatitis through nanotechnology are being developed. Nanotechnology significantly reduces the cost of screening. In this review, the potential of three-dimensional-nanostructured carbon substances as promising materials due to fewer side effects, and the contribution of these particles to effective tissue transfer in the treatment and diagnosis of hepatitis due to the importance of rapid diagnosis for successful treatment, were extensively investigated. In recent years, three-dimensional carbon nanomaterials such as graphene oxide and nanotubes with special chemical, electrical, and optical properties have been used for the diagnosis and treatment of hepatitis due to their high potential. We expect that the future position of nanoparticles in the rapid diagnosis and treatment of viral hepatitis can be better determined.

Functionalization of Metal and Carbon Nanoparticles with Potential in Cancer Theranostics

Cancer theranostics is a new concept of medical approach that attempts to combine in a unique nanoplatform diagnosis, monitoring and therapy so as to provide eradication of a solid tumor in a non-invasive fashion. There are many available solutions to tackle cancer using theranostic agents such as photothermal therapy (PTT) and photodynamic therapy (PDT) under the guidance of imaging techniques (e.g., magnetic resonance-MRI, photoacoustic-PA or computed tomography-CT imaging). Additionally, there are several potential theranostic nanoplatforms able to combine diagnosis and therapy at once, such as gold nanoparticles (GNPs), graphene oxide (GO), superparamagnetic iron oxide nanoparticles (SPIONs) and carbon nanodots (CDs). Currently, surface functionalization of these nanoplatforms is an extremely useful protocol for effectively tuning their structures, interface features and physicochemical properties. This approach is much more reliable and amenable to fine adjustment, reaching both physicochemical and regulatory requirements as a function of the specific field of application. Here, we summarize and compare the most promising metal- and carbon-based theranostic tools reported as potential candidates in precision cancer theranostics. We focused our review on the latest developments in surface functionalization strategies for these nanosystems, or hybrid nanocomposites consisting of their combination, and discuss their main characteristics and potential applications in precision cancer medicine.

Molecular inversion probe-rolling circle amplification with single-strand poly-T luminescent copper nanoclusters for fluorescent detection of single-nucleotide variant of SMN gene in diagnosis of spinal muscular atrophy

In this study, a simple fluorescent detection of survival motor neuron gene (SMN) in diagnosis of spinal muscular atrophy (SMA) based on nucleic acid amplification test and the poly-T luminescent copper nanoclusters (CuNCs) was established. SMA is a severely genetic diseases to cause infant death in clinical, and detection of SMN gene is a powerful tool for pre- and postnatal diagnosis of this disease. This study utilized the molecular inversion probe for recognition of nucleotide variant between SMN1 (c.840 C) and SMN2 (c.840 C  >  T) genes, and rolling circle amplification with a universal primer for production of poly-T single-strand DNA. Finally, the fluorescent CuNCs were formed on the poly-T single-strand DNA template with addition of CuSO₄ and sodium ascorbate. The fluorescence of CuNCs was only detected in the samples with the presence of SMN1 gene controlling the disease of SMA. After optimization of experimental conditions, this highly efficient method was performed under 50 °C for DNA ligation temperature by using 2U Ampligase, 3 h for rolling circle amplification, and the formation of the CuNCs by mixing 500 μM Cu²⁺ and 4 mM sodium ascorbate. Additionally, this highly efficient method was successfully applied for 65 clinical DNA samples, including 4 SMA patients, 4 carriers and 57 wild individuals. This label-free detection strategy has the own potential to not only be a general method for detection of SMN1 gene in diagnosis of SMA disease, but also served as a tool for detection of other single nucleotide polymorphisms or nucleotide variants in genetic analysis through designing the different sensing probes.

Shape-Controlled Synthesis of Dumbbell-like Pt-Fe3O4-MnO x Nanoparticles by Governing the Reaction Kinetics

The production of shape-controlled heterometallic nanoparticles (NPs) consisting of Pt and nonprecious metal oxides is crucial to demonstrate the composition-property relationship of NPs. Herein, we report a facile one-pot approach for the controlled synthesis of dumbbell-like Pt-Fe₃O₄-MnO _x and dendritic Pt-MnO _x NPs. The key to the success of this synthesis is in changing the quantity of Fe(CO)₅ additive to control the reaction kinetics. In the absence of Fe(CO)₅, dendritic Pt-MnO _x NPs were synthesized through the assembly of small seed NPs. On the other hand, dumbbell-like Pt-Fe₃O₄-MnO _x NPs were obtained in the presence of Fe(CO)₅ through controlling the nucleation and growth of Fe and Mn on the Pt NPs, followed by air oxidation. Compared to a Pt/graphene oxide (GO) catalyst, dumbbell-like Pt-Fe₃O₄-MnO _x NPs on GO showed an enhancement of specific activity toward the oxygen reduction reaction owing to the compressive-strain effect exerted on the Pt lattice.

Acetylpyrene-labelled 7-methylguanine nucleotides: unusual fluorescence properties and application to decapping scavenger activity monitoring

7-Methylguanosine (m(7)G) nucleotides labelled with acetylpyrene (AcPy) were synthesized as fluorescent mRNA 5' end (cap) analogues. The unique fluorescent properties of m(7)G-AcPy conjugates, different from G-AcPy, can be applied to studying various mRNA cap-related processes including the evaluation of putative inhibitors of DcpS enzyme-a therapeutic target in neuromuscular diseases.

Development of an Aptamer-Based Sensing Platform for Metal Ions, Proteins, and Small Molecules through Terminal Deoxynucleotidyl Transferase Induced G-Quadruplex Formation

We report a label-free, structure-independent luminescent-sensing platform for metal ions, proteins, and small molecules utilizing an Ir(III) complex, terminal deoxynucleotidyl transferase (TdT), and a structure-folding aptamer. A novel G-quadruplex-selective Ir(III) complex was identified to detect the nascent G-quadruplex motifs with an enhanced luminescence response. Unlike most label-free DNA-based assays reported in the literature, this sensing platform does not require a specific secondary structure of aptamer, thus greatly simplifying DNA design. The detection platform was demonstrated by the detection of K(+) ions, thrombin, and cocaine as representative examples of metal ions, proteins, and small molecules.

A Luminescent Cocaine Detection Platform Using a Split G-Quadruplex-Selective Iridium(III) Complex and a Three-Way DNA Junction Architecture

In this study, a series of 10 in-house cyclometalated iridium(III) complexes bearing different auxiliary ligands were tested for their selectivity toward split G-quadruplex in order to construct a label-free switch-on cocaine detection platform employing a three-way junction architecture and a G-quadruplex motif as a signal output unit. Through two rounds of screening, we discovered that the iridium(III) complex 7 exhibited excellent selectivity toward the intermolecular G-quadruplex motif. A detection limit as low as 30 nM for cocaine can be achieved by this sensing approach with a linear relationship between luminescence intensity and cocaine concentration established from 30 to 300 nM. Furthermore, this sensing approach could detect cocaine in diluted oral fluid. We hope that our simple, signal-on, label-free oligonucleotide-based sensing method for cocaine using a three-way DNA junction architecture could act as a useful platform in bioanalytical research.

Au nanoparticles supported on magnetically separable Fe2O3–graphene oxide hybrid nanosheets for the catalytic reduction of 4-nitrophenol

A one-pot hydrothermal synthesis approach was developed to prepare FeSO₄·(H₂O)–graphene oxide (GO) nanosheets. Au nanoparticles were immobilized onto this support, giving Au/Fe₂O₃–GO nanocomposites.

The graphene/nucleic acid nanobiointerface

In this critical review, we present the recent advances in the design and fabrication of graphene/nucleic acid nanobiointerfaces, as well as the fundamental understanding of their interfacial properties and various nanobiotechnological applications.