Detection and Quantification of Tightly Bound Zn in Blood Serum Using a Photocaged Chelator and a DNAzyme Fluorescent Sensor.

DNAzymes have emerged as a powerful class of sensors for metal ions due to their high selectivity over a wide range of metal ions, allowing for on-site and real-time detection. Despite much progress made in this area, detecting and quantifying tightly bound metal ions, such as those in the blood serum, remain a challenge because the DNAzyme sensors reported so far can detect only mobile metal ions that are accessible to bind the DNAzymes. To overcome this major limitation, we report the use of a photocaged chelator, XDPAdeCage to extract the Zn from the blood serum and then release the chelated Zn into a buffer using 365 nm light for quantification by an 8-17 DNAzyme sensor.

Rapid Quantitative Fluorescence Detection of Copper Ions with Disposable Microcapsule Arrays Utilizing Functional Nucleic Acid Strategy.

In this work, an economical and easy-to-use microcapsule array fabricated by ice printing technique has been realized for ultrasensitive fluorescence quantification of copper ions employing functional nucleic acid strategy. With ice printing, the detection reagents are sealed by polystyrene (PS) film isolation and photopolymer, which guarantees a stable and contamination-free environment for functional nucleic acid reaction. Our microcapsule arrays have shown long-term stability (20 days) under -20 °C storage in frozen form before use.

A disposable microcapsule array chip fabricated by ice printing combined with isothermal amplification for Salmonella DNA detection.

In this work, a novel microcapsule array chip was fabricated for the detection of Salmonella DNA by integrating an ice-printing technique with DNA isothermal amplification. Reaction solutions were previously sealed in the microcapsule array chip ice printing. To protect the relatively fragile DNA isothermal amplification system, an extra polystyrene (PS) film was introduced to isolate the reaction solution from photopolymer precursor, which was proved to be a vital step for providing a clean and stable environment for DNA amplification reaction.

Investigation of the interactions between methylene blue and intramolecular G-quadruplexes: an explicit distinction in electrochemical behavior.

G-quadruplex sequences exist in eukaryotic organisms and prokaryotes, and the investigation of the interactions between G-quadruplexes and small molecule ligands is important for gene therapy, biosensor fabrication, fluorescence imaging and so on. Here, we investigated the behaviour of methylene blue (MB), an electroactive molecule, in the presence of different intramolecular G-quadruplexes by an electrochemical method using a miniaturized electrochemical device based on its intrinsic electrochemical properties. Although the effects of MB on different intramolecular G-quadruplex structures are not obvious by circular dichroism spectroscopy, distinct differences in the binding affinities of MB with different intramolecular G-quadruplexes were quickly and easily observed by an electrochemical technique.

A cupric ion triggered DNA diode based on a tandem linkage-cleavage reaction.

Based on click chemistry and DNAzyme, we constructed for the first time a cupric ion triggered DNA diode using a tandem linkage-cleavage process, which could occur in order in a programmable and autonomous manner. This DNA diode is a new DNA functional element and can precisely control the translation direction of information.

A smart tailor-made G-clip reporter for sensitive detection of G-triplet-containing sequences.

Taking advantage of the intrinsic characteristics of G-triplet-containing sequences, a pioneering tailor-made clip-like reporter containing three-fourths of a G-quadruplex is established. The reporter can clip the G triplet in the target sequence through a recognition process to form a complete G-quadruplex structure.

DNA cross-triggered cascading self-amplification artificial biochemical circuit.

The construction of compact and robust artificial biochemical circuits based on nucleic acids can help researchers to understand the essential mechanisms of complex biological systems, and design sophisticated strategies for various requirements. In this study, a novel DNA cross-triggered cascading self-amplification artificial biochemical circuit was developed. Once triggered by trace amounts (as low as 2 amol) of either of two fully independent oligonucleotide factors under homogeneous isothermal conditions, the circuit simultaneously amplified both factors by 10-10 fold, which was proved using mass spectrometry.

A G-quadruplex based platform for label-free monitoring of DNA reaction kinetics.

Research on the kinetic characteristics and mechanisms of DNA reactions is crucial for bioengineering and biosensing. A G-quadruplex, which can form a peroxidase-mimicking DNAzyme with hemin, was for the first time used to establish a versatile platform for kinetic investigations on DNA reactions. G-quadruplex sequence EAD2 was incorporated into the corresponding nucleic acid reaction as product.