The cortisol in human body is a crucial biomarker in terms of wellness management, mental state monitoring and stress-related disorder diagnosis. Therefore, the rapid, reliable and facile measurement of cortisol concentration has attracted extensive research interest. However, traditional cortisol detection such as immunosensing requires demanding laboratory layout, lengthy procedures and high costs, which means, consequently, it is incompatible with the current goal of cortisol sensing. Given the contradiction, an electrochemical sensor based on molecularly imprinted polymer (MIP) for simple, efficient, non-invasive cortisol detection was proposed. The two-step approach employed is simple enough and allows for the mass production of devices. And the embedding of Prussian Blue (PB) within the MIP layer eliminates the need for complex external probes, thereby making the resultant sensors more suitable for integration into wearable devices. We firstly demonstrated the feasibility of the proposed strategy and characterized the successful formation of cavities specific to cortisol molecules. Thereafter, we measured the dependence of the current response on cortisol concentration in Phosphate Buffered Saline (PBS) buffer, which revealed a near-linear relationship between the logarithm of the cortisol concentration and the redox current from 10−9 mol/L to 10−5 mol/L, covering the optimal range of cortisol concentration in sweat. Subsequently, sensors with the same specifications were prepared and tested in PBS buffer, exhibiting good consistency. In artificial sweat, we further demonstrated that they have benign selectivity, interference immunity and great potential in practical applications.

This study explores the manipulation of photonic nanojets (PNJs) via axial illumination of cylindrical dielectric particles with cylindrical vector beams (CVBs). The edge diffraction effect of cylindrical particles is harnessed to achieve the near-field focusing of CVBs, minimizing the spherical aberration’s impact on the quality of the PNJ. By discussing how beam width, refractive index, and particle length affect PNJs under radially polarized incidence, a simple and effective approach is demonstrated to generate rod-like PNJs with uniform transmission distances and super-diffraction-limited PNJs with pure longitudinal polarization. Azimuthal polarization, on the other hand, generates tube-like PNJs. These PNJs maintain their performance across scale. Combining edge diffraction with CVBs offers innovative PNJ modulation schemes, paving the way for potential applications in particle trapping, super-resolution imaging, photo-lithography, and advancing mesotronics and related fields.

This work reports on the theoretical study and results on the generation and control of photonic hooks (PHs) through uniaxial crystals (calcite as an example). Completely different mechanisms and effects are obtained in typical rectangular and cylindrical structures, respectively. PHs generated by the rectangular structure no longer have a single inflection point but have a specific dual-inflection-point feature. The calcite cylindrical structure can generate a PH with a size comparable to that of the structure, and dynamic adjustment can be achieved through the angle between the incident and optical axes. By changing the polarization state of the incident field, active switching between photonic nanojet and PH can be achieved in both types of structures. The proposed generation and modulation scheme can be extended to other anisotropic materials. (c) 2024 Optica Publishing Group

The cortisol molecules in human body is a crucial biomarker in terms of wellness management, mental state monitoring and stress-related disorder diagnosis. Therefore, the rapid, reliable and facile measurement of cortisol concentration has attracted extensive research interest. However, traditional cortisol detection such as immunosensing requires demanding laboratory layout, lengthy procedures and high costs, which means, consequently, it is incompatible with the current goal of cortisol sensing. Given the contradiction, an electrochemical sensor based on molecularly imprinted polymer (MIP) for simple, efficient, non-invasive cortisol detection was proposed. The two-step approach employed is simple enough and allows for the mass production of devices. And the synthesis of MIP involving implanted Prussian Blue (PB) could get rid of the reliance of complex external probes, leading the resultant sensors are more suitable for assembly with wearable devices. We firstly characterized the successful formation of cavities specific to cortisol molecules. Thereafter, we measured the dependence of the current response on cortisol concentration in PBS buffer, which revealed a near-linear relationship between the logarithm of the cortisol concentration and the redox current from 1 × 10−9 mol/L to 10 × 10−6 mol/L, covering the optimal range of cortisol concentration in sweat. Subsequently, sensors with the same specifications were prepared and tested in PBS buffer, exhibiting good consistency. In artificial sweat, we further demonstrated that they have benign selectivity and great potential in practical applications.

Flexible wearable sweat sensors allow continuous, real-time, noninvasive detection of sweat analytes, provide insight into human physiology at the molecular level, and have received significant attention for their promising applications in personalized health monitoring. Electrochemical sensors are the best choice for wearable sweat sensors due to their high performance, low cost, miniaturization, and wide applicability. Recent developments in soft microfluidics, multiplexed biosensing, energy harvesting devices, and materials have advanced the compatibility of wearable electrochemical sweat-sensing platforms. In this review, we summarize the potential of sweat for medical detection and methods for sweat stimulation and collection. This paper provides an overview of the components of wearable sweat sensors and recent developments in materials and power supply technologies and highlights some typical sensing platforms for different types of analytes. Finally, the paper ends with a discussion of the challenges and a view of the prospective development of this exciting field.

Fabrication and improvement of high-efficient, durable, and earth-abundant non-precious metal hydrogen evolution electrocatalysts are particularly important in the production of clean energy hydrogen. In this study, we synthesized Co:FeS2/CoS2 nano-heterostructure with superior hydrogen evolution performance by a typical one-step hydrothermal method. When the temperature of HER solution was raised from 0 °C to 60 °C, the overpotential for Co:FeS2/CoS2 nano-heterostructure at 10 cm–2 was reduced from 115 to 75 mV and its Tafel slope did not change significantly. Moreover, the overpotential for Co:FeS2/CoS2 nano-heterostructure increased by only 6 mV after 1000 cycles of CV at 60 °C. This work provides a strategy for preparing and improving the performance of non-precious metal electrocatalysts to replace precious metal electrocatalysts.

This study aims to evaluate the change in telomere length in peripheral white blood cells of patients with atherosclerosis. Biological age may be distinct from chronological age. Mean telomere length provides an assessment of biological age, with shorter telomeres indicating older biological age. We investigated whether patients with atherosclerosis had shorter leukocyte telomere length. One hundred patients, excluding those with acute or chronic inflammation, cancer, and autoimmune diseases, were entered into this study and divided into two groups: atherosclerosis group (AS group) and control group. The two groups were matched in respect to age, gender and smoking status. Telomere length was measured as the mean length of the terminal restriction fragments (TRFs) in peripheral leukocytes, using the Southern blotting and software analysis of scanned autoradiographic images. Telomere length in peripheral white blood cells of AS group was markedly shorter than that of control group (mean +/- SD: 7.48 +/- 1.14 kb vs. 8.18 +/- 0.73 kb, P < 0.001). The telomere length in peripheral white blood cells correlated negatively with patients' age in both groups (P = 0.02; P < 0.001). The difference in mean TRF length between the AS and control groups was not accounted for by other coronary risk factors. Compared with patients in the highest quartile of telomere length, the risk of atherosclerosis was increased 2.8-3.2-fold (P < 0.0001) in patients with telomeres shorter than the average. In comparison with the control group, telomere length in white blood cells of the AS group was markedly shorter. This finding supports the concept that biological age may play a role in the etiology of AS.

Self-assembled DNA nanostructures hold great promise as nanoscale templates for organizing nanoparticles (NPs) with near-atomistic resolution. However, large-scale organization of NPs with high yield is highly desirable for nanoelectronics and nanophotonic applications. Here, we design five-strand DNA tiles that can readily self-assemble into well-organized micrometer-scale DNA nanostructures. By organizing gold nanoparticles (AuNPs) on these self-assembled DNA nanostructures, we realize the fabrication of one- and two-dimensional Au nanostructures in single steps. We further demonstrate the one-pot synthesis of Au metamaterials for highly amplified surface-enhanced Raman Scattering (SERS). This single-step and high-yield strategy thus holds great potential for fabricating plasmonic metamaterials.

Semiconducting metal sulfides have raised strong research interest among researchers as a promising candidate for light-assisted electrochemical water splitting, because they have wide band gap. In order to harvest more light wavelengths for improvement of light-assisted electrochemical water splitting capacity, we fabricated SnS₂/SnS heterojunction nanosheets via facile and environmental route. The SnS₂/SnS heterojunction nanosheets were used as photo-electrocatalytic material which exhibited low over potential of -0.64 V at the current density of 10 mA·cm-2 in 0.5 M NaSO₄ solution. Moreover, the SnS and SnS₂ nanosheets displayed high over potential values of -0.80 and -0.88 V at the current density of 10 mA·cm-2, respectively. This research finding may therefore show the potential for use of SnS₂/SnS heterojunction nanosheets as low cost and environmentally friendly photo-electrocatalysis.

A highly sensitive photomagnetic microfluidic chip was designed to achieve one-step detection of low concentration substances by integrating three-dimensional chip fabrication, bidirectional magnetic micro particle technology, and total reflection imaging technique. The new device takes advantage of three functions of magnetic particles: enrichment, separation and speckle imaging. The total reflection optical magnetic imaging eliminates the use of chemiluminescent or fluorescent reagents, reducing the number of detection steps. The optimization of the electromagnetic control simulation, the microfluidic simulation analysis, and the 3D chip structure are detailed. A bidirectional converter magnetic field technology can accelerate the sandwich immune reaction with enrichment of the marker, improving the accuracy and speed of detection. Due to a high precision one-step immunoassay, the detection time is less than 5 min, and the amount of sample needed is very low (<10 mu L). A series of concentrations of C-reactive protein (CRP) was used for pattern detection, and signals obtained from CRP at 0.02 to 20 ng/mL were analyzed to generate a standard calibration curve. The novel one-step multiparameter optical chip detection system is uniquely suited for rapid early diagnosis in a clinical setting, as well as for biological research applications.

DNA origami have been established as versatile templates to fabricate plasmonic nanostructures in predefined shapes and multiple dimensions. Limited to the size of DNA origami, which are approximate to 100 nm, it is hard to assemble more intricate plasmonic nanostructures in large scale. Herein, we used rectangular DNA origami as the template to anchor two 30-nm gold nanoparticles(Au NPs) which induced dimers nanostructures. Transmission electron microscopy(TEM) images showed the assembly of Au NPs with high yields. Using the linkers to organize the DNA origami templates into nanoribbons,chains of Au NPs were obtained, which was validated bythe TEM images. Furthermore, we observed a significant Raman signal enhancement from molecules covalently attached to the Au NP-dimers and Au NP-chains. Our method opens up the prospects of high-ordered plasmonic nanostructures with tailored optical properties.

Plasmonic nanostructures with distinct spatial configuration and geometry are of considerable significance because of their desired optical response. These optical responses have close relationship with the inter-particle parameters in plasmonic nanostructures. However, the precise control of the consecutive variation of these parameters remains a formidable challenge. Here, we demonstrate a gold nanoparticle (AuNP) -based plasmonic nano-reporter, in which a AuNP performs as a walker to stepwise roll directionally and progressively on DNA origami. Using another AuNP as a stator, the rolling of the AuNP reporter could generate the inter-particle distance variation, which would be monitored by surface-enhanced Raman scattering (SERS). Our method opens up a door to develop an optical reporter that monitors inter-particle variations in plasmonic nanostructures.

DNA origami has been established as addressable templates for site-specific anchoring of gold nanoparticles (AuNPs). Given that AuNPs are assembled by charged DNA oligonucleotides, it is important to reduce the charge repulsion between AuNPs-DNA and the template to realize high yields. Herein, we developed a cavity-type DNA origami as templates to organize 30 nm AuNPs, which formed dimer and tetramer plasmonic nanostructures. Transmission electron microscopy images showed that high yields of dimer and tetramer plasmonic nanostructures were obtained by using the cavity-type DNA origami as the template. More importantly, we observed significant Raman signal enhancement from molecules covalently attached to the plasmonic nanostructures, which provides a new way to high-sensitivity Raman sensing.

In this research, nanostructures were prepared by depositing gold on the top surface of CdS nanorod array. Finite difference time domain simulation was performed to better understand the resonance in the near-infrared region by varying the edge length and thickness of the gold nanodisks. The absorption spectrum in the near-infrared region shows a resonance peak due to localized surface plasmons (LSP). This resonance position can be turned over the near-infrared region by varying the diameter of the disks. The simulation results are consistent with the experimental observation, indicating its promising applications in near-infrared detection.