Advanced Sensor and Energy Materials最新文献

It is economically desirable to develop a material that can simultaneously detect and recover uranium. Herein, a CC-bridged two-dimensional metal-covalent organic framework (Cu-BTAN-AO MCOF) was constructed by condensation of metal single crystals with a rigid structure (Cu₃(PyCA)₃) and cyano monomers (BTAN) via Knoevenagel reaction for simultaneous detection and adsorption of uranium. The amidoxime group within the pore and the presence of unsaturated Cu(I) in the framework facilitate the adsorption of uranyl ions onto the amidoxime group, leading to fluorescence quenching via the photoinduced electron transfer (PET) mechanism, achieving a detection limit of as low as 167 nM uranyl ions. Furthermore, Cu-BTAN-AO demonstrates exceptional efficiency in capturing uranium from wastewater characterized by rapid kinetics and superior selectivity. It is noteworthy that Cu-BTAN-AO is the first example of simultaneous detection, adsorption and chemical reduction of uranium using metal centers and functional groups in MCOF, indicating that Cu-BTAN-AO has great potential for the detection and recovery of uranium-containing wastewater. This design strategy may also be applicable to advancing sensing and energy materials for other important metal ions.

Spherical nucleic acids (SNAs) are a 3D spherical nanostructure composed of highly oriented, dense layers of oligonucleotides conjugated to a hollow or solid core. This structure allows SNAs to show resistance to nuclease degradation, enter into nearly all cells without transfection agents and enable precise interactions with target molecules. Based on superior biological properties, SNAs can be tailored for diverse biological applications, rendering them a flexible and biosafe tool for biological applications as well as an enabling platform for therapy. In this review, we mainly discuss the structure and conjugation mode of SNAs and focus on recent advances in their applications, such as biomedical detection, imaging, and drug delivery. Finally, the remaining challenges and future directions of SNAs are also discussed and proposed.

The exploration of efficient lead-free perovskite photoelectric active materials to develop high-performance photoelectrochemical (PEC) systems in aqueous solution is crucial to expand their PEC applications. Herein, we successfully constructed a high-performance PEC platform using ligand-free perovskite Cs₂PdBr₆ microcrystals (MCs) as the photoactive substance. The Cs₂PdBr₆ MCs showed narrow bandgap, wide absorption range, high electronic mobility and good stability in aqueous solutions. Particularly, the Cs₂PdBr₆ MCs exhibited an excellent photoresponse, the photocurrent density could reach as high as 98 μA/cm² under 10.18 mW/cm² light irradiation in the absence of other electron acceptors. In addition of the extremely wide range of response wavelength, wide pH range and accelerated interfacial carrier transfer, the Cs₂PdBr₆ MCs demonstrated the significant potential of photocathode active material for applications in PEC sensors and optoelectronic devices. Therefore, this work indicates that Cs₂PdBr₆ MCs design is a highly efficient way to solve the intrinsic issues of perovskite material, predicting a promising strategy for high performance PEC application in aqueous ambience.

Although immobilization-free and label-free electrochemical DNA (E-DNA) biosensors have engaged tremendous interest due to their superior properties, such as easy operation, time-saving and cost-saving, most of them are fabricated in homogeneous modes and usually produce high background current. In the present work, we proposed a new immobilization-free and label-free heterogeneous E-DNA assay based on a dual-blocker-aided multibranched hybridization chain reaction (HCR) for one-pot nucleic acid detection with zero background. The target nucleic acid triggers the HCR involving cascaded hybridization between two metastable hairpins, resulting in the generation of HCR products with multibranched arms, which can be captured onto the electrode via π-π stacking interactions between multibranched arms and reduced graphene oxide (rGO). Prior to the incubation process with an electrode, two blockers are designed to prohibit the nonspecific absorption of unreacted hairpin probes. Thus, an immobilization-free and label-free heterogeneous electrochemical assay for one-pot nucleic acid detection with zero background is readily realized. This strategy also presents additional merits of simplicity and cheap cost, since probe immobilization, signal tag labeling, and multiple incubation processes are avoided. Therefore, the as-proposed effective and versatile biosensor has great potential to be applied in nucleic acid-related practical biosensing.

Optical sensors provide a fast and real-time approach to detect benzene, toluene, ethylbenzene, and xylenes (BTEX) in environmental monitoring and industrial safety. However, detecting the concentration of a particular gas in a mixture can be challenging. Here, we develop a machine-learning model that can precisely measure BTEX concentrations simultaneously based on an absorption spectroscopy gas sensing system. The convolutional neural network (CNN) is utilized to identify the absorbance spectra for each volatile, along with their concentrations in a mixture. A synthetic data set is generated using a series of physics-based simulations to create the predictive model. The data set consists of the overall absorbance of numerous random BTEX mixtures over time, based on various percentages of the permissible exposure limit (PEL). It is worth noting that benzene has a negligible absorbance (very low PEL, 1–5 ppm) compared to other volatile gases, which makes it difficult to detect. To address this challenge, we introduce a 3-stage solution to accurately discriminate between all BTEX species, regardless of their concentration levels. As a result, the R-squared above 0.99 for toluene, ethylbenzene, and o-xylene, and the R-squared above 0.96 for benzene, is achieved, indicating the model's capability to predict BTEX concentrations.

DNA hydrogels are three-dimensional polymer networks constructed using DNA as the structural building block. Due to the tight binding between hydrophilic groups on DNA chains and water molecules, they exhibit outstanding plasticity and fluid thermodynamic properties, making them one of the best choices for mimicking natural biological tissues. By controlling the backbone building blocks, gelation conditions, and cross-linking methods of DNA hydrogels, hydrogels with different mechanical strengths can be obtained, thus expanding their applications in the field of biology. This review first introduces the relationship between the mechanical properties of DNA hydrogels and their structure, elucidates the approaches and strategies for mechanical property modulation, and focuses on the scheme of controllable design to modulate the mechanical properties of DNA hydrogels for applications in biosensing, cellular function regulation, and bone tissue engineering. Furthermore, this review outlines the future development directions and challenges faced in the mechanical property modulation of DNA hydrogels, providing useful information for the precise design of DNA hydrogels for biological research.

G-quadruplex is a high-level structure composed of folded DNA or RNA rich in tandem repeats of guanine (G). In recent years, G-quadruplex is widely used in various fields due to its unique structural properties. This article briefly introduces the structural properties of G-quadruplex, and provides a brief introduction to the research on DNA and RNA G-quadruplex in various detection and medical fields. It is hoped that this can provide some help to readers who want to understand G-quadruplex.

Ratiometric DNA biosensors, which utilize DNA as the recognition element and integrate dual signals from diverse sensing platforms including fluorescence, electrochemistry, and surface-enhanced Raman scattering (SERS), have demonstrated remarkable proficiency in detecting a wide range of targets. In this review, we showcase the significant progress achieved by ratiometric biosensors. Firstly, ratiometric biosensors have made notable advancements in analyzing real samples. These include the analysis of pH values near cancer cells, quantification of miRNA in human cell lysates, detection of human telomerase RNA in cell extracts, and performing DNA logic-gated in situ bioimaging on cell membranes. Secondly, excellent sensitivity has been attained through the utilization of effective amplification methods such as RCA, HCR, and CHA, among others. Thirdly, the construction of stable reference signals has resulted in significantly improved precision for ratiometric biosensors. This breakthrough has overcome matrix effects, enabling reliable detection in real samples with high selectivity. This review provides a comprehensive overview of recent advancements in strategies employed by ratiometric DNA biosensors. We present three types of biosensors based on distinct sensing platforms: fluorescent, electrochemical, and SERS biosensors. Additionally, we discuss future directions and primary challenges in the development of ratiometric DNA biosensors.