Advanced Sensor and Energy Materials最新文献

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.

The Nigella Sativa seeds were utilized for the environment-friendly zinc oxide nanoparticles (ZnO NPs), as evident by the observation of a white precipitate. Numerous analytical techniques, such as XRD, FTIR, UV–vis, SEM, and EDX, were utilized to describe the specimen's structural, optical, and electrical properties. XRD analysis was used to confirm that the ZnO NPs were crystalline. An absorbance peak at 401 nm was observed in the UV–vis, indicating that the ZnO NPs have a 2.91 eV bandgap. Functional groups are present in ZnO NPs, as seen by the FTIR graph. The nanoparticles' spherical form and average size of 37.9 nm were confirmed by the SEM image. EDX analysis confirmed the composition of the nanoparticles, with zinc accounting for 73.17% and oxygen for 26.83%. ZnO NPs demonstrated excellent electrical conductivity because of their higher surface-to-volume ratio. Additionally, the synthesis of ZnO NPs exhibited effective degradation of methylene blue dye. These results point to potential applications in several domains, including electronics, biomedical devices, industry, and agriculture, and they call for immediate follow-up research.

Herein, we proposed novel three-in-one DNA nanowheels with simultaneous chemo and gene therapy to treat tumor, especially to prevent simultaneous drug resistance, which could be disassembled via a cascaded hybridization reactions triggered by the highly expressed microRNA in cancer cells for smart and efficient cancer therapy. Typically, with breast cancer as a model, microRNA 21 could trigger the self-disassembly of DNA nanowheel 1 via hybridization with a specially designed oligonucleotide (anti-microRNA 21) in DNA nanowheel 1, releasing another special oligonucleotide (Contact sequence) to trigger the self-disassembly of DNA nanowheel 2 with releasing of a special oligonucleotide (anti-Contact sequence) to trigger the self-disassembly of DNA nanowheel 1 cyclically, and thus the cascaded hybridization reactions with three-in-one anti-cancer functions could be generated based on three main therapeutic effects via releasing doxorubicin to inhibit macromolecular biosynthesis, antisense oligonucleotide of microRNA 21 to activate the apoptotic cell pathway and antisense oligonucleotide of MDR1 to prevent the drug resistance respectively. As expected, the proposed method showed improved therapeutic efficacy on the cancer cells with about 80% apoptosis ratio, especially on the drug resistant cancer cells with about 75% apoptosis ratio, compared with that in the conventional anti-cancer systems of about 70% on cancer cells and below 40% on drug resistant cancer cells, respectively. Most importantly, this strategy opened the door for generation of complex functional DNA-based structures for target triggering drugs releasing system combining with chemo- and gene-therapy to generate tumor regression and prevent drug resistance with an optimized therapeutic efficacy, providing a new avenue for efficient cancer treatment, especially drug resistant cancers.

This research presents the fabrication and characterization of an interdigitated capacitive (IDC) sensor on a wooden substrate using pencil traces. The resistance of the pencil traces decreased from 100 kΩ to 5 kΩ as the pencil grade shifted from HB to 8B. Concurrently, capacitance measurements revealed an increase from approximately 5 pF for a 5-finger IDC made with HB pencil to around 32 pF for an 8B pencil counterpart. Increasing the number of pencil traces from 10 to 50 resulted in a significant decrease in resistance and a proportional increase in capacitance. Application of the IDC sensor demonstrated notable changes in capacitance upon proximity and touch, with a significant decrease upon removal. The interdigitated capacitance sensor exhibits good proximity effects and contact sensitivity in touch, with capacitance increasing exponentially from 0.3 pF (7 cm) to 1.2 pF (direct contact), highlighting its ability to detect objects with high precision. Additionally, environmental factors such as temperature and humidity influence capacitance values. These findings underscore the potential of pencil-drawn IDC sensors for responsive and adaptable applications in various fields.

The pre-analytical steps in blood-based liquid biopsy, involving sample collection techniques and storage conditions, play a critical role in ensuring the integrity and reliability of collected samples. These steps have a directly impact on the accuracy and reliability of test results and are therefore of utmost importance. Mass spectrometry (MS)-based proteomics is an exceptionally powerful tool in the field of liquid biopsy. It enables the comprehensive analysis of the protein content within biological specimens, providing valuable insights into the underlying mechanisms and pathogenesis of diseases. In this study, we aim to explore the variations in the protein landscape between serum and plasma specimens and evaluate the impact of delayed centrifugation on LC/MS-analyzed protein profiles. We seek to provide recommendations on optimal pre-analytical protocols for MS-based proteomics studies. This will enhance the accuracy and reliability of liquid biopsy for precision medicine, ultimately leading to improved patient outcomes.

It is well-known that high specific surface area and improved pore structure is significantly desired for the application of supercapacitor based on biomass-based activated carbon. Herein, Sargassum thunbergii was selected as carbon precursor. Then, a simple and environmentally friendly method was designed to synthesize heteroatom self-doped porous carbon materials via synchronous activation and graphitization by using K₂FeO₄. Our results demonstrated that activation temperature plays an important role in porous structure, morphology, and degree of graphitization, thus affecting the performance of supercapacitance. Sargassum thunbergii-based graphitized porous carbons STGPC-2 sample (calcination temperature at 700 °C) has a large specific surface area (1641.98 m² g⁻¹), pore volume (0.91 cm³ g⁻¹), high microporosity (V_micro = 0.62 cm³ g⁻¹, more than 68%), and a certain degree of graphitization. In three-electrode system, The STGPC-2 electrode exhibited a high specific capacitance of 325.5 F g⁻¹ at 0.5 A g⁻¹ and displays high rate capability (248 F g⁻¹ at 10 A g⁻¹ in 6 M KOH electrolyte). The symmetric STGPC-2 supercapacitor exhibits energy density as high as 21.3 Wh kg⁻¹ (at a power density of 450 W kg⁻¹) and excellent long-term cycling stability (97% capacitance retention after 3000 cycles) in 1 M Na₂SO₄ electrolyte.