Butyl Benzyl Phthalate in Urban Sewage by Magnetic-Based Immunoassay: Environmental Levels and Risk Assessment

A magnetic-based immunoassay (MBI) combined with biotin-streptavidin amplification was proposed for butyl benzyl phthalate (BBP) investigation and risk assessment. The values of LOD (limit of detection, IC10) and IC50 were 0.57 ng/mL and 119.61 ng/mL, with a detection range of 0.57–24977.71 ng/mL for MBI. The specificity, accuracy and precision are well demonstrated. A total of 36 environmental water samples of urban sewage from Zhenjiang, China, were collected and assessed for BBP contamination. The results show that BBP-positive levels ranged from 2.47 to 89.21 ng/mL, with a positive rate of 77.8%. The health effects of BBP in the urban sewage were within a controllable range, and the ambient severity for health (ASI) was below 1.49. The highest value of AS for ecology (ASII) was 7.43, which indicates a potential harm to ecology. The entropy value of risk quotient was below 100, the highest being 59.47, which poses a low risk to the environment and ecology, indicating that there is a need to strengthen BBP controls. The non-carcinogenic risk of BBP exposure from drinking water was higher for females than that for males, and the non-carcinogenic risk from drinking-water and bathing pathways was negligible. This study could provide an alternative method for detecting BBP and essential information for controlling BBP contamination.

Succinyl-κ-carrageenan Silver Nanotriangles Composite for Ammonium Localized Surface Plasmon Resonance Sensor

This research investigates the physicochemical properties of biopolymer succinyl-κ-carrageenan as a potential sensing material for NH4+ Localized Surface Plasmon Resonance (LSPR) sensor. Succinyl-κ-carrageenan was synthesised by reacting κ-carrageenan with succinic anhydride. FESEM analysis shows succinyl-κ-carrageenan has an even and featureless topology compared to its pristine form. Succinyl-κ-carrageenan was composited with silver nanoparticles (AgNP) as LSPR sensing material. AFM analysis shows that AgNP-Succinyl-κ-carrageenan was rougher than AgNP-Succinyl-κ-carrageenan, indicating an increase in density of electronegative atom from oxygen compared to pristine κ-carrageenan. The sensitivity of AgNP-Succinyl-κ-carrageenan LSPR is higher than AgNP-κ-carrageenan LSPR. The reported LOD and LOQ of AgNP-Succinyl-κ-carrageenan LSPR are 0.5964 and 2.7192 ppm, respectively. Thus, AgNP-Succinyl-κ-carrageenan LSPR has a higher performance than AgNP-κ-carrageenan LSPR, broader detection range than the conventional method and high selectivity toward NH4+. Interaction mechanism studies show the adsorption of NH4+ on κ-carrageenan and succinyl-κ-carrageenan were through multilayer and chemisorption process that follows Freundlich and pseudo-second-order kinetic model.

Development of a europium nanoparticles lateral flow immunoassay for NGAL detection in urine and diagnosis of acute kidney injury

Background AKI is related to severe adverse outcomes and mortality with Coronavirus Disease 2019 (COVID-19) patients, that early diagnosed and intervened is imperative. Neutrophil gelatinase-associated lipocalin (NGAL) is one of the most promising biomarkers for detection of acute kidney injury (AKI), but current detection methods are inadequacy, so more rapid, convenient and accuracy methods are needed to detect NGAL for early diagnosis of AKI. Herein, we established a rapid, reliable and accuracy lateral flow immunoassay (LFIA) based on europium nanoparticles (EU-NPS) for the detection of NGAL in human urine specimens. Methods A double-antibody sandwich immunofluorescent assay using europium doped nanoparticles was employed and the NGAL monoclonal antibodies (MAbs) conjugate as labels were generated by optimizing electric fusion parameters. Eighty-three urine samples were used to evaluate the clinical application efficiency of this method. Results The quantitative detection range of NGAL in AKI was 1-3000 ng/mL, and the detection sensitization was 0.36 ng/mL. The coefficient of variation (CV) of intra-assay and inter-assay were 2.57-4.98 % and 4.11-7.83 %, respectively. Meanwhile, the correlation coefficient between europium nanoparticles-based lateral fluorescence immunoassays (EU-NPS-LFIA) and ARCHITECT analyzer was significant (R2 = 0.9829, n = 83, p < 0.01). Conclusions Thus, a faster and easier operation quantitative assay of NGAL for AKI has been established, which is very important and meaningful to diagnose the early AKI, suggesting that the assay can provide an early warning of final outcome of disease.

Non-invasive laparoscopic detection of small tumors of the digestive tract using inductive sensors of proximity

The precise location of gastric and colorectal tumors is of paramount importance for the oncological surgeon as it dictates the limits of resection and the extent of lymphadenectomy. However, this task proves sometimes to be very challenging, especially in the laparoscopic setting when the tumors are small, have a soft texture, and do not invade the serosa. In this view, our research team has developed a new instrument adapted to minimally-invasive surgery, and manipulated solely by the operating surgeon which has the potential to locate precisely tumors of the digestive tract. It consists of an inductive proximity sensor and an electronic block encapsulated into an autoclavable stainless-steel cage that works in tandem with an endoscopic hemostatic clip whose structure was modified to increase detectability. By scanning the serosal side of the colon or stomach, the instrument is capable to accurately pinpoint the location of the clip placed previously during diagnostic endoscopy on the normal bowel mucosa, adjacent to the tumor. In the current in-vivo experiments performed on large animals, the modified clips were transported without difficulties to the point of interest and attached to the mucosa of the bowel. Using a laparoscopic approach, the detection rate of this system reached 65% when the sensor scanned the bowel at a speed of 0.3 cm/s, and applying slight pressure on the serosa. This value increased to 95% when the sensor was guided directly on the point of clip attachment. The detection rate dropped sharply when the scanning speed exceeded 1 cm/s and when the sensor-clip distance exceeded the cut-off value of 3 mm. In conclusion, the proposed detection system demonstrated its potential to offer a swift and convenient solution for the digestive laparoscopic surgeons, however its detection range still needs to be improved to render it useful for the clinical setting.

Wearable Radar System Design on Semi-Flexible PCB for Visually Impaired People

This paper presents a compact and wearable frequency-modulated continuous-wave (FMCW) radar on a semi-flexible printed circuit board (PCB) for an anti-collision system. This can enable visually impaired people to perceive their environment better and more safely in their everyday lives. In the proposed design, a multiple-input multiple-output (MIMO) antenna array with four receivers (RXs) and three transmitters (TXs) has been designed to achieve obstacle-detection ability in both horizontal and vertical planes through a specific geometrical configuration. Operating at 76–81 GHz, an aperture coupled wide-beam patch antenna with two parasitic patches is proposed for each channel of RXs and TXs. The fast Fourier transform (FFT) algorithm has been implemented in the radar chip AWR1843 for intermediate frequency (IF) signals to generate a range-Doppler map and search precise target angles in high sensitivity. The complete system, which includes both the MIMO antenna array and the radar chip circuit, is utilized on a six-layer semi-flexible PCB to ensure compactness and ease in wearability. Field testing of the complete system has been performed, and an obstacle-detection range of 7 m (for humans) and 19 m (for larger objects) has been obtained. A wide angular detection range of 64-degree broadside view (±32°) has also been achieved. A voice module has also been integrated to deliver the obstacle’s range and angle information to visually impaired persons.

A dual-ended 400 km OFDR for vibration detection

Optical frequency-domain reflectometer (OFDR) has been widely used in vibration detection because of its unique advantages of simple configuration and high spatial resolution. Based on remote fiber amplification, an unrepeatered OFDR is experimentally investigated for vibration monitoring. To locate the vibration, we present an algorithm by calculating segmental cross-correlation between the beating signals with and without disturbances on the sensing fiber. It is shown that the OFDR demonstrates the ability of detecting the vibration over 222 km testing distance (112 km + 110 km). After sensing the first spool fiber of 112 km, the remnant laser is amplified by a remote-pumped EDFA before proceeding to probe the vibration in the second spool one of 110 km. To be specific, the PZT-induced vibrations positioned at z=110.9 km and z=220.9 km are both detected. More importantly, the OFDR system can be extended to operate in bi-directional sensing mode and to double detection range from 200 km to 400 km.

High sensitivity dual core photonic crystal fiber sensor for simultaneous detection of two samples

The optical control ability of photonic crystal fiber (PCF) is a distinctive property suitable for improving sensing and plasma performance. This article proposes a dual-core D-channel PCF sensor that can detect two samples simultaneously, which effectively solves the problems of coating difficulty and low wavelength sensitivity. The PCF has four layers of air holes, which dramatically reduces the optical fiber loss and is more conducive to the application of sensors in actual production. In addition, by introducing dual cores on the upper and lower sides of the central air hole, reducing the spacing between the core and the gold nanolayer, a stronger evanescent field can be generated in the cladding air hole. The optical fiber sensor can detect the refractive index of two samples simultaneously with a maximum sensitivity of 21300 nm/RIU. To the best of our knowledge, the sensitivity achieved in this work is the highest sensitivity with the dual sample synchronous detection sensors. The detection range of the refraction index is 1.35-1.41, and the resolution of the sensor is 4.695×10-6. Overall, the sensor will be suitable for medical detection, organic chemical sensing, analyte detection, and other fields.

A CMOS Integrator-Based Clock-Free Time-to-Digital Converter for Home-Monitoring LiDAR Sensors

This paper presents a nine-bit integrator-based time-to-digital converter (I-TDC) realized in a 180 nm CMOS technology for the applications of indoor home-monitoring light detection and ranging (LiDAR) sensors. The proposed I-TDC exploits a clock-free configuration so as to discard clock-related dynamic power consumption and some notorious issues such as skew, glitch, and synchronization. It consists of a one-dimensional (1D) flash TDC to generate coarse-control codes and an integrator with a peak detection and hold (PDH) circuit to produce fine-control codes. A thermometer-to-binary converter is added to the 1D flash TDC, yielding four-bit coarse codes so that the measured detection range can be represented by nine-bit digital codes in total. Test chips of the proposed I-TDC demonstrate the measured results of the 53 dB dynamic range, i.e., the maximum detection range of 33.6 m and the minimum range of 7.5 cm. The chip core occupies the area of 0.14 × 1.4 mm2, with the power dissipation of 1.6 mW from a single 1.2-V supply.

Ratiometric Electrochemical Biosensor Based on Internally Controlled Duplex PCR for Detection of Mycobacterium Tuberculosis

The pathogenic bacteria Mycobacterium tuberculosis (MTB) is responsible for tuberculosis, which is well known as the globally leading cause of death. The likelihood of false negative interpretation as well as potential influence from intrinsic and extrinsic factors are considerably minimized by the incorporation of internal control (IC) detection in the developed assay platform. Ratiometric electrochemical (REC) biosensor for detection of MTB was developed based on the IC integration via duplex PCR (dPCR) and a dual-signal electrochemical readout. The MTB- or IC-specific PNA probe was labeled with methylene blue (MB) or ferrocene (FC), respectively at the C terminus, producing a strong square wave voltammetry signal. Interaction of the ICdPCR product could induce changes in the dynamics of these two redox-labeled PNA probes (MTB-MB and IC-FC) that were attached to the screen-printed gold electrode via formation of a self-assembled monolayer. Using this MB as a reporter and FC as an IC, the REC ICdPCR biosensor achieved a broad detection range from 10 fM to 10 nM and a detection limit of 1.26 fM, corresponding to approximately 2.5 bacteria cells. The REC ICdPCR biosensor was applied to MTB measurement in practical samples, exhibiting high accuracy and more importantly high practicability.