Advanced Sensor Research最新文献

A serous effusion is a buildup of extra fluid in the serous cavities including pleural, peritoneal, and pericardial cavities. It is important to distinguish benign reactive effusions from effusions caused by malignant proliferation in cytopathology since different diagnoses can lead to completely different disease staging and therapeutic choices. The conventional cytopathology procedure has the disadvantages of low throughput and low objectivity. To enhance the efficiency and accuracy of malignant serous effusion diagnosis, in this paper, an imaging flow cytometry, called optofluidic time-stretch microscopy is first employed, to image the cells in the serous effusion at an event rate of 100 000 events per second and with a spatial resolution better than 1 µm. The acquired cellular images are then analyzed using a convolutional neural network, by which the malignant cells are accurately detected. The performance of the method is validated with 18 clinical samples, including 14 malignant and 4 benign ones. The results show that the method can detect malignant cells at an accuracy of 90.53%. The high throughput, high accuracy, and high convenience of the method make it a potential solution for malignant serous effusion diagnosis in various scenarios.

This review delves into the significant advancements in microfluidic technology since 2017, highlighting its critical role in shrinking device sizes and integrating advanced surface functionalization techniques. It showcases how microfluidics, an interdisciplinary field, has revolutionized fluid manipulation on a microscale, enabling the creation of cost-effective, portable devices for on-the-spot analyses, like heavy metal ion detection. From its early days rooted in ancient observations to cutting-edge uses of materials like silicon, glass, polydimethylsiloxane (PDMS), and paper, this review charts microfluidics’ dynamic evolution. It emphasizes the transformative impact of surface functionalization methods, including silanization and plasma treatments, in enhancing device materials' performance. Moreover, this review anticipates the exciting convergence of microfluidics with emerging technologies like droplet microfluidics and three-dimensional (3D) printing, alongside nanotechnology, forecasting a future of sophisticated analytical tools, point-of-care diagnostics, and improved detection systems. It acknowledges the hurdles in scaling production and achieving universal reliability and standardization. This review highlights the transformative impact of microfluidic technology on diagnostics and environmental surveillance, emphasizing its utility in deploying compact sensors for comprehensive and concurrent evaluations of water quality.

Flexible Modulus Sensor

In article 2300148, Hengchang Bi, Xing Wu, and co-workers report a modulus sensing system with a characteristic of high linearity detection, which consists of a pressure sensor and a vibrator. It is able to quickly identify the physiological state of human body based on the modulus change of the detected tissues, exhibiting great potential in the health monitoring, such as the concept eye mask for migraine monitoring.

Painless, needleless delivery of drugs through the skin can be realized through aphenomenon called sonophoresis by applying an ultrasound field to the biological tissue. Development of wearable embodiments of such systems demands comprehensive characterization of both the physical mechanism of sonophoresisas well as wearability parameters. Here, we present a framework for analyzing disk-type piezoelectric transducers in a polymeric substrate to create acoustic cavitation in a fluid coupling medium for sonophoresis applications. The device design and operating parameters such as the working frequency, applied voltage range, acoustic pressure distribution, and transducer spacing were determine dusing a finite element methods (FEM),and verified with experimental measurements. The influence of the surrounding water and tank reflections on the acoustic pressure field, and the interaction between the elements in the array structure were also studied.Finally, the impact of skin and the substrate geometry on the acoustic pressure fields was characterized to simulate the invivo use-case of the system. These analytical models can be used to guide critical parameters for device design such as the separation distance of the piezoelectric transducer from the skin boundary. We envision that this tool boxwill support rapid design iteration for realization of wearable ultrasound systems.

Organic X-ray sensors are a promising new class of detectors with the potential to revolutionize medical imaging, security screening, and other applications. However, the development of high-performance organic X-ray sensors is challenged by low sensitivity. This paper reports on the development of nine X-ray sensors based on new organic materials. It is demonstrated that the incorporation of bromine atoms into the sidechains of carbazolyl-containing organic molecules significantly enhances their X-ray sensitivity. This research suggests that incorporating a variety of high-atomic-number chemical elements into well-established organic semiconductors is a promising strategy for designing efficient X-ray sensor materials.

Optical fiber technology is gaining increasing importance in all those fields requiring reliable, miniaturized, compact, and plug-and-play devices, with a special relevance in life science applications. Here, optical fibers are adopted to measure the fluids viscosity, by detecting the transit time (related to viscosity) of a steel bead moving through the tested fluid in a microfluidic channel under constant pressure. The proposed optofluidic system is designed by defining a theoretical model, here experimentally validated in the viscosity range of 5–110 cP, well resembling main blood flow features. The achieved results demonstrate the capability to work in multi-point and single-point detection modalities with a trade-off between resolution (minimum of 10⁻¹ and 1 cP respectively) and measurement time (tens of seconds and milliseconds range, respectively). An optimum accuracy close to 1.5% has been achieved, with room for further optimization by reducing bead size uncertainty. The proposed platform features simple, low-cost, reliable, and fast measurements and ensures the integration with microfluidics chip in a miniaturized and disposable system. The low volumes required (scalable down to µL range) and the ease of use enable the translation of the proposed platform in clinical scenarios involving real-time blood and plasma viscosity measurements under physiological conditions.

The greener alternatives to tactile-integrated multimodal sensors with self-powered and self-healing abilities are highly desirable for all-in-one autonomous sensing systems, particularly impressive in diverse application ranges including smart home, healthcare, and e-skin. The dynamically self-healable, stretchable piezoresistive sensors, and triboelectric nanogenerators (TENGs) reported herein are constructed by a facile, industrially viable method of grafting imidazolium ions on epoxidized natural rubber (ENR) backbone. Owing to cation-π and π–π interaction between the percolated carbon nanotubes (CNTs)-network and the imidazolium ions formed by non-covalent interactions, the interfacial adhesion between the filler and elastomer is shown to improve considerably. The sensors show high piezoresistive strain sensitivity, reversible ionic network-assisted self-healability (efficiency ≈80%) and wide-ranging detectability for precise monitoring of human movements. Both the healed and pristine sensors feature low hysteresis and stable electrical outputs over a wide strain range (≤200%). While achieving rapid self-healing efficiency, the substrates are shown to exhibit remarkable robustness for harsh climates owing to significant mechanical toughness. Supported by excellent triboelectric tactile sensitivity (2.12 V N⁻¹), the multifunctional TENG-enabled sensor yields superior power density (0.16 mW cm⁻²). Moreover, the TENG module exhibits high force sensitivity and ease of operation that are considered versatile for all-weather integrated tactile solutions for future technology.

Pathogenic microorganisms contaminating potable water are a serious water quality concern because they have severe consequences for human and environmental health. Managing water contamination requires the availability of fast and highly sensitive point-of-use detection systems responsive to a wide concentration range. In the present work, this goal is achieved by realizing a cascade-structured biosensor that exploits innovative stimuli-responsive materials such as gold nanorods (AuNRs) and photosensitive nematic liquid crystals (NLCs). The cascade structure is fabricated by interfacing a glass substrate in a back-to-front arrangement, hosting an array of bioactivated AuNRs and an NLC cell. The AuNRs array integrates microfluidic channels, allowing direct water sampling and the analysis of reduced water volumes with high sensitivity. The biosensor combines in the same device two independent optical transducers: a bioactive AuNRs array (plasmonic biosensor), sensitive to refractive index alterations, and an NLC cell that detects the presence of pathogens by responding to light intensity variations. The plasmonic biosensor performs exceptionally well for very low concentrations of bacteria. In contrast, the NLC biosensor works for high-concentration bacteria, thus providing a cascade-like detection system able to detect bacteria in a wide concentration range from 10 to 10⁹ CFU mL⁻¹.

The excitation of microresonators using focused intensity modulated light, known as photothermal excitation, is gaining significant attention due to its capacity to accurately excite microresonators without distortions, even in liquid environments, which is driving key advancements in atomic force microscopy and related technologies. Despite progress in the development of coatings, the conversion of light into mechanical movement remains largely inefficient, limiting resonator movements to tens of nanometers even when milliwatts of optical power are used. Moreover, how photothermal efficiency depends on the relative position of a microresonator along the propagation axis of the photothermal beam remains poorly studied, hampering the understanding of the conversion of light into mechanical motion. Here, photothermal measurements are performed in air and water using cantilever microresonators and a custom-built picobalance, to determine how photothermal efficiency changes along the propagation beam axis. It is identified that far out-of-band laser emission can lead to visual misidentification of the beam waist, resulting in a drop of photothermal efficiency of up to one order of magnitude. The measurements also unveil that the beam waist is not always the position of highest photothermal efficiency, and can reduce the efficiency up to 20% for silicon cantilevers with trapezoidal cross section.