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Multiloop splitter-based non-cryogenic artificial trapping (M-SNAT) modulation technique was developed, miniaturized and applied in comprehensive two-dimensional gas chromatography (GC×GC) for analysis of cannabis samples. The approach employed deactivated fuse silica (DFS) columns configured into multiple loop splitter system halving the perimeters of the progressively upstream loops. This splitter device was located between the first (1D) semi-nonpolar column outlet and a microfluidic Deans switch (DS). Each splitter loop splits a peak into two subpeaks having the same area with different void times. Three loops were then applied resulting in the number of the split subpeaks (nsplit) of 8 for each peak, and retention time differences between any two adjacent subpeaks (∆tR,split) were the same. By applying periodic heartcut event (H/C) within every artificial modulation period (PAM) of nsplit×∆tR,split, comprehensive split-and-trapped modulation profiles of analytes could be selectively transferred onto the second (2D) polar column (30 m) without cryogen consumption. This artificial modulation system was applied for analysis of cannabis samples with enhanced 2D peak capacity (2nc∼15). The established method was applied to analyse cannabis extracts using vegetable oils with or without frying process. This reveals 454 different peaks with 76, 92, 35 and 70 specific components specifically observed by using olive oil extraction (OE), fried OE, coconut oil extraction (CE) and fried CE, respectively.

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Chronic kidney disease (CKD) is a widespread condition with considerable health and economic impacts globally. However, existing methodologies for serum creatinine assessment often involve prolonged wait times and sophisticated equipment, such as spectrometers, hindering real-time diagnosis and care. Innovative solutions like point-of-care (POC) devices are emerging to address these challenges. In this context, there is a recognized need for remote, regular, automated, and low-cost analysis of serum creatinine levels, given its role as a critical parameter for CKD diagnosis and management. This study introduces a miniaturized system with integrated heater elements designed for precise serum creatinine measurement. The system operates based on the Jaffe method and accurate serum creatinine measurement within a microreservoir chip. Smartphone-based image processing using the hue-saturation-value (HSV) color space was applied to captured images of microreservoirs. The creatinine analyses were conducted in serum with a limit of detection of ~ 0.4 mg/dL and limit of quantification of ~ 1.3 mg/dL. Smartphone-based image processing employing the HSV color space outperformed spectrometric analysis for creatinine measurement conducted in serum. This pioneering technology and smartphone-based processing offer the potential for decentralized renal function testing, which could significantly contribute to improved patient care. The miniaturized system offers a low-cost alternative ($87 per device), potentially reducing healthcare expenditures (~ $0.5 per test) associated with CKD diagnosis and management. This innovation could greatly improve access to diagnosis and monitoring of CKD, especially in regions where access to sophisticated laboratory equipment is limited.

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A novel compact and highly selective Ultra Wide Band (UWB) filter is proposed using multimode resonator (MMR) technology. To begin with, the filter's ultra-wideband performance is achieved by coupling a stepped-triangular multimode resonator with input-output feedlines. Furthermore, dual-notch band characteristics are realized at 6.80 GHz and 9.82 GHz, employing asymmetric coupled lines and the split ring resonator (SRR) methods. Eventually, by using a Defected Ground Structure (DGS), the filter's correct transmission zero is deepened, further enhancing the out-of-band suppression performance at higher frequencies. The measured results are in excellent agreement with the experimental results, and the filter has a passband range of 3.52-11.68 GHz, a center frequency of 7.59 GHz, an insertion loss of just 0.61 dB, and a return loss of more than 18 dB. The transmission zeros have a rejection capability of more than 47 dB attenuation, and the rectangular coefficient of the filter is 1.34, which is outstanding for filtering out the interference signals in the parasitic passband with superior selectivity. The overall structure is compact, and the size is just 0.41λg×0.20λg. The filter can be used for UWB system filtering and also to avoid interference from some Wireless Local Area Network (WLAN) IEEE 802.11 series and x-band satellite link frequency bands.

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A new flow batch (FB) system for chemical vapor generation (CVG) is proposed for mercury (Hg) determination in fish. An inductively coupled plasma mass spectrometer was used as a detector. Low-cost peristaltic mini pumps were used to propel the solutions and different configurations of FB systems (reactor/gas/liquid separator) were studied. The proposed configuration of the FB-CVG system allows good sensitivity, low limit of detection (LOD) and low consumption of reagents and sample solutions. In summary, only 1 mL of reductant, 1 mL of acid and 0.16 mL of sample are needed. The proposed method has good linearity, precision (better than 5 %), LOD of 0.008 µg g-1 and LOQ of 0.012 µg g-1, and high sample throughput, allowing 90 measurements/h. The accuracy of the method was evaluated through the analysis of a certified reference material (DOLT-4 Dogfish Liver), whose result is in good agreement with certified value (t-test with 95 % confidence level) and the quantification limit meets current legislations, of 1.0 µg g-1 (Brazil) and 0.3 µg g-1 (EU). In addition, analyte recovery test was done, where Hg recovery was better than 95 %, demonstrating the good analytical performance of the method. To demonstrate the applicability of the method, five samples of fish tissue (muscle) were analyzed. The proposed FB-CVG system, in addition to being low cost, is robust and requires only the volume of reagents necessary for Hg vapor generation, producing a very low amount of waste. It can be concluded that the proposed system can be used for routine analysis for Hg determination in fish tissue. It is worth noting that with the appropriate adjustments, the system can be coupled to different Hg detectors.

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The study demonstrates the potential of an optical nose made by depositing an array of fluorescent nanomaterials on a paper substrate for the early detection of leukemia in adults. This is based on the fact that blood volatile organic compounds (VOCs) are useful leukemia biomarkers. The integrated design was miniaturized and comprised both sensing zones and a sample holding zone, which were installed on a small sheet of paper within a miniature cubic reaction chamber fabricated by using 3D printing technology. The sensing device, comprising seven fluorescent sensing elements, namely, metal nanoclusters, quantum dots, and carbon dots was capable of detecting VOCs in the blood headspace and providing a colorimetric signature that could discriminate between blood samples from healthy and cancerous individuals. A total of 70 new leukemia cases and 51 healthy controls aged 20-50 years were studied. The device required a 60 µL portion of the blood sample and reacted to blood VOCs after 3 h when kept at 50 °C. The imaging data from the device was processed by linear discriminant analysis, and the results confirmed efficient identification of patient samples from healthy samples with 100% accuracy. Overall, the array system is noninvasive (or minimally invasive), portable, fast, inexpensive, and requires only a small amount of blood sample.

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To address the increasing demand for sensitive and selective sample preparation methods for metal analysis; preconcentration of intended analyte from complex sample matrices before analysis is required to improve the performance of analysis instruments. In this study, we have engineered a sustainable and portable syringe-based hand-operable three-dimensionally (3D) printed sample pretreatment apparatus equipped with a replaceable bio-based thin- film metal sorbent. This device effectively addresses the challenges of sample matrix interference in metal analysis. A metal sorbent film composed of chitosan (CS) and polydopamine (PDA) leveraged the diverse functional groups in the CS/PDA matrix to significantly enhance the extraction efficiency for various metals. Our approach demonstrated excellent analytical performance, with coefficients of determination (R2) of 0.9982 for copper (Cu) and 0.996 for chromium (Cr). The method achieved low limits of detection (LOD) of 0.3 µg L-1 for Cr and 0.7 µg L-1 for Cu. Precision and practicality assessments using actual urine samples yielded satisfactory relative standard deviations (RSD%) ranging from of 1.6 %-8.5 % for both metals, indicating minimal interference from the sample matrix. Moreover, our approach exhibited robust performance even after seven consecutive extraction and desorption cycles, highlighting its sustainability and practical applicability for laboratory and on-site sample pretreatment.

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In recent years, miniaturized analytical instruments have been developing to meet the needs of portable and rapid analysis. The key of miniaturized analytical equipment is the miniaturization and integration of functional modules. This paper aims to develop a miniaturized photometric detector and separation microfluidic chip for a liquid chromatography (LC) system. The detector uses a light-emitting diode to emit ultraviolet light, which is collimated by an internal double lens. A Z-shaped flow cell with a long optical path is designed and fabricated in the separation microfluidic chip with a three-layer structure, which provides a tubing-free connection between the separation and detection unit. Detector performance is evaluated using hemoglobin (Hb) samples, with an upper limit of detection linearity (95 %) of 0.345 AU and stray light level as low as 0.08 %. Additionally, the microchip channel can be filled with cation exchange resin and C18 particles. Finally, an ion LC system and a reversed-phase LC system were constructed based on the miniaturized photometric detector and two microchips with different packed columns, respectively, and were successfully used in the separation and detection of two metabolic markers (glycated hemoglobin or bilirubin). The results of this study are expected to facilitate the development of a portable LC system and their application in community health services and family health management of chronic diseases.

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Fluorescence detection has always suffered from high background fluorescence from real samples such as milk. Therefore, cumbersome pretreatments of samples were necessary to remove the fluorescent substances but led to long processing times and low efficiency. Time-resolved luminescence detection is a powerful technique for eliminating short-lived background fluorescence without additional pretreatments. However, the related instruments are usually equipped with high-speed excitation sources and detectors, which are always bulky and expensive. Herein, we developed a low-cost and miniaturized imaging system for high-throughput time-gated luminescence detection. An UV LED array was used to excite multiple samples, the luminescence of which could be detected by a smartphone simultaneously. An analog circuit was designed to synchronize the LED to the mechanical chopper to eliminate the background signals resulting from scattering and short-lived autofluorescence. Compared to other synchronous circuits based on FPGAs and microcontrollers, this analog circuit required no programming and memory. For the first time, high-throughput time-resolved luminescence detection of tetracycline in milk without any separation or enrichment was achieved by utilizing a smartphone as a camera, and the scattered signals and the background fluorescence were eliminated efficiently. The limit of detection reached as low as 53 nM (∼0.024 ppm), lower than the residue limit set by the European Union. This high-throughput time-gated luminescence detection method can be used for quantitative analysis of many real samples with high background fluorescence.

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Imaging live cells under stable culture conditions is essential to investigate cell physiological activities and proliferation. To achieve this goal, typically, a specialized incubation chamber that creates desired culture conditions needs to be incorporated into a microscopy system to perform cell monitoring. However, such imaging systems are generally large and costly, hampering their wide applications. Recent advances in the field of miniaturized microscopy systems have enabled incubator cell monitoring, providing a hospitable environment for live cells. Although these systems are more cost-effective, they are usually limited in imaging modalities and spatial temporal resolution. Here, we present a dual-mode, image-enhanced, miniaturized microscopy system (termed MiniCube) for direct monitoring of live cells inside incubators. MiniCube enables both bright field imaging and fluorescence imaging with single-cell spatial resolution and sub-second temporal resolution. Moreover, this system can also perform cell monitoring inside the incubator with tunable time scales ranging from a few seconds to days. Meanwhile, automatic cell segmentation and image enhancement are realized by the proposed data analysis pipeline of this system, and the signal-to-noise ratio (SNR) of acquired data is significantly improved using a deep learning based image denoising algorithm. Image data can be acquired with 5 times lower light exposure while maintaining comparable SNR. The versatility of this miniaturized microscopy system lends itself to various applications in biology studies, providing a practical platform and method for studying live cell dynamics within the incubator.

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With the rapid proliferation of portable and wearable electronics, energy autonomy through efficient energy harvesting has become paramount. Thermoelectric generators (TEGs) stand out as promising candidates due to their silent operation, high reliability, and maintenance-free nature. This paper presents the design, fabrication, and analysis of a micro-scale TEG for powering such devices. A planar configuration was employed for its inherent miniaturization advantages. Finite element analysis using ANSYS reveals that a double-layer device under a 50 K temperature gradient generates an impressive open-circuit voltage of 1417 mV and a power output of 2.4 µW, significantly exceeding its single-layer counterpart (226 mV, 0.12 µW). Validation against the analytical model results yields errors within 2.44% and 2.03% for voltage and power, respectively. Furthermore, a single-layer prototype fabricated using paper shadow masks and sputtering deposition exhibits a voltage of 131 mV for a 50 K temperature difference, thus confirming the feasibility of the proposed design. This work establishes a foundation for developing highly efficient micro-TEGs for powering next-generation portable and wearable electronics.

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Ultrasound (US) has gained popularity as a guidance modality for percutaneous needle insertions because it is widely available and non-ionizing. However, coordinating scanning and needle insertion still requires significant experience. Current assistance solutions utilize optical or electromagnetic tracking (EMT) technology directly integrated into the US device or probe. This results in specialized devices or introduces additional hardware, limiting the ergonomics of both the scanning and insertion process. We developed the first ultrasound (US) navigation solution designed to be used as a non-permanent accessory for existing US devices while maintaining the ergonomics during the scanning process. A miniaturized EMT source is reversibly attached to the US probe, temporarily creating a combined modality that provides real-time anatomical imaging and instrument tracking at the same time. Studies performed with 11 clinical operators show that the proposed navigation solution can guide needle insertions with a targeting accuracy of about 5 mm, which is comparable to existing approaches and unaffected by repeated attachment and detachment of the miniaturized tracking solution. The assistance proved particularly helpful for non-expert users and needle insertions performed outside of the US plane. The small size and reversible attachability of the proposed navigation solution promises streamlined integration into the clinical workflow and widespread access to US navigated punctures.

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Microbatteries are emerging as a sustainable, miniaturized power source, crucial for implantable biomedical devices. Their significance lies in offering high energy density, longevity, and rechargeability, facilitating uninterrupted health monitoring and treatment within the body. The review delves into the development of microbatteries, emphasizing their miniaturization and biocompatibility, crucial for long-term, safe in-vivo use. It examines cutting-edge manufacturing techniques like physical and chemical vapor deposition, and atomic layer deposition, essential for the precision manufacture of the microbatteries. The paper contrasts primary and secondary batteries, highlighting the advantages of zinc-ion and magnesium-ion batteries for enhanced stability and reduced reactivity. It also explores biodegradable batteries, potentially obviating the need for surgical extraction post-use. The integration of microbatteries into diagnostic and therapeutic devices is also discussed, illustrating how they enhance the efficacy and sustainability of implantable biosensors and bioelectronics.

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A novel "windmill" three-channel light-emitting diode induced fluorescence detector (LED-IF) was proposed to maximize the excitation efficiency and fluorescence collection efficiency. Compared with the typical collinear arrangement, the fluorescence intensity of the three channels was increased by 7.85, 3.88, and 2.94 times, respectively. The compact shaping optical path was designed to obtain higher excitation efficiency and a lower background stray light effect caused by high divergence angle high-power ultraviolet (UV)-LEDs simultaneously, which increased the sensitivity of three channels by 4.6 to 5.7 times. It was found that using a photodiode (PD) with a flat window and a larger photosensitive surface can collect the Lambertian emission fluorescence in the flow cell more efficiently, increasing the signal-to-noise ratio of each channel 1.3 to 1.8 times. The limits of detection (LODs, 3 times peak-peak noise) of aflatoxin B2 (AFB2), ochratoxin (OTA), and zearalenone (ZEN) were 0.33, 1.80, and 28.2 ng/L, respectively. Finally, six mycotoxins were analyzed simultaneously by the detector coupling with HPLC. The results showed that the sensitivity of the detector was at the best level to date, which was better than that of the top commercial fluorescence detectors (FLDs). The developed detector has the advantages of having small volume, low cost, and long lifetime and being robust, which has wide application and market prospects.

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Exploring the relationship between neuronal dynamics and ethologically relevant behaviour involves recording neuronal-population activity using technologies that are compatible with unrestricted animal behaviour. However, head-mounted microscopes that accommodate weight limits to allow for free animal behaviour typically compromise field of view, resolution or depth range, and are susceptible to movement-induced artefacts. Here we report a miniaturized head-mounted fluorescent mesoscope that we systematically optimized for calcium imaging at single-neuron resolution, for increased fields of view and depth of field, and for robustness against motion-generated artefacts. Weighing less than 2.5 g, the mesoscope enabled recordings of neuronal-population activity at up to 16 Hz, with 4 µm resolution over 300 µm depth-of-field across a field of view of 3.6 × 3.6 mm2 in the cortex of freely moving mice. We used the mesoscope to record large-scale neuronal-population activity in socially interacting mice during free exploration and during fear-conditioning experiments, and to investigate neurovascular coupling across multiple cortical regions.

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The greater and more widespread use of chemicals, either from industry or daily use, is leading to an increase in the discharge of these substances into the environment. Some of these are known to be hazardous to humans and the environment and are regulated, but there is a large and increasing number of substances which pose a potential risk even at low concentration and are not controlled. In this context, new techniques and methodologies are being developed to deal with this concern. Miniaturized liquid chromatography (LC) emerges as a greener and more sensitive alternative to conventional LC. Furthermore, advances in instrument miniaturization have made possible the development of portable LC instrumentation which may become a promising tool for in-situ monitoring. This work reviews the environmental applications of miniaturized LC over the last 15 years and discusses the different instrumentation, including off- and on-line pretreatment techniques, chromatographic conditions, and contributions to the environmental knowledge.

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Techno-functional properties of protein isolates such as emulsification, foaming, and gelling serve as key indicators to determine their food applications. Conventional macro-volume techniques used to measure these techno-functional properties are usually time consuming, require large amounts of protein samples, and are impractical when diverse protein samples are handled at the early screening stage. To overcome these issues, we have developed scaled-down (miniaturized) assays to test techno-functional properties of protein samples. These assays are simple, efficient, and require <400 µl of protein solution. Specifically, the miniaturized emulsification and gelling assays require 25-fold less protein than conventional macro-volume techniques and the miniaturized foaming assay requires 100-fold less sample. The performance of these assays has been thoroughly validated using conventional techno-functional tests for each parameter. The protocols described herein offer high-throughput screening capabilities, accelerating the testing process for protein techno-functional properties and allowing for quick identification of samples of interest from diverse samples. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Miniaturized emulsification assay Alternate Protocol 1: Conventional macro-volume emulsification assay Basic Protocol 2: Miniaturized foaming assay Alternate Protocol 2: Conventional macro-volume foaming assay Basic Protocol 3: Miniaturized gelling assay Alternate Protocol 3: Conventional macro-volume gelling assay.

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Photoacoustic imaging (PAI) utilizes the photoacoustic effect to record both vascular and functional characteristics of a biological tissue. Photoacoustic signals have typically low amplitude that cannot be read efficiently by data acquisition systems. This necessitates the use of one or more amplifiers. These amplifiers are somewhat bulky (e.g., the ZFL-500LN+, Mini-Circuits, USA, or 351A-3-50-NI, Analog Modules Inc., USA). Here, we describe the fabrication and development process of a transducer with a built-in low-noise preamplifier that is encased within the transducer housing. This new, to the best of our knowledge, design could be advantageous for applications where a compact transducer + preamplifier is required. We demonstrate the performance of this compact detection unit in a laser scanning photoacoustic microscopy system by imaging a rat ear ex vivo and a rat brain vasculature in vivo.

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Complexed and tiresome pretreatment processes have significantly impeded in-field analysis of environmental specimens. Herein, an all-in-one sample separation and enrichment strategy based on a compact charge-selective capture/nanoconfined enrichment (CSC/NCE) device is exploited for marker-free surface-enhanced Raman spectroscopy (SERS) detection of charged pesticides in matrix specimens. This tactic incorporating in situ separations, seizing, and nanoconfined enhancement can greatly elevate the effectiveness of sample pretreatment. Importantly, CSC/NCE with excellent adsorption performances and excellent plasmonic features facilitates concentration and signal amplification of electrically charged pesticides. With the introduction of an electric field on this integrated CSC/NCE, the matrix effect in samples could be significantly eradicated, and a distinct SERS response is witnessed for targeted analytes. Accurate quantification of multipesticides is achieved by synergizing the CSC/NCE chip and chemometrics, and the contents found by the CSC/NCE-based sensing strategy agree with those obtained from chromatography assays with relative deviations lower than 10%. The facile and versatile all-in-one tactic infused in a compact chip exhibits enormous potential for field-test application in chemical measurement and food safety.

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