A novel and accurate microfluidic assay of CD62L in bladder cancer serum samples.

We report a low-cost, sensitive, bead-based electrochemical immunoarray for soluble L-selectin (or CD62L protein), a potential biomarker for staging bladder cancer. We used a semi-automated modular microfluidic array with online antigen capture on superparamagnetic beads, which were subsequently delivered to a detection chamber housing multiple sensors. The assay was designed to accurately detect CD62L in diluted serum with a limit of detection (LOD) of 0.25 ng mL-1 and a dynamic range of 0.25-100 ng mL-1. The microfluidic array gave significantly better accuracy and higher sensitivity than a standard ELISA kit, which was shown to be subject to significant systematic error at high and low concentration ranges. 31 serum samples from patients with varying grades of bladder cancer and cancer-free controls were analyzed by the immunoarray and ELISA, and the CD62L levels correlated. This work establishes a new accurate assay for determining CD62L levels and highlights the potential of this protein as a biomarker for detecting locoregional progression of bladder cancer.

All printable snow-based triboelectric nanogenerator.

The development of power generators that can function in harsh snowy environments and in contact with snow can be beneficial but challenging to accomplish. Herein, we introduce the first snow-based triboelectric nanogenerator (snow-TENG) that can be used as an energy harvester and a multifunctional sensor based on the principle of snow-triboelectrification. In this work, we used a 3D printing technique for the precise design and deposition of the electrode and triboelectric layer, leading to flexible, stretchable and metal-free triboelectric generators. Based on the single electrode mode, the device can generate an instantaneous output power density as high as 0.2 mW/m2, an open circuit voltage up to 8 V, and a current density of 40 µA/m2. In addition, the snow-TENG can function as a miniaturized weather station to monitor the weather in real time to provide accurate information about the snowfall rate, snow accumulation depth, wind direction, and speed in snowy and/or icy environments. In addition, the snow-TENG can be used as a wearable power source and biomechanical sensor to detect human body motions, which may prove useful for snow-related sports. Unlike conventional sensor platforms, our design works without the need for batteries or image processing systems. We envision these devices could potentially be integrated into solar panels to ensure continuous power supply during snowy weather conditions.

Determination of Triazines and Triazoles in Grapes Using Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionization High-Resolution Mass Spectrometry.

A chromatography-free atmospheric pressure matrix-assisted laser desorption/ionization high-resolution mass spectrometry (AP-MALDI HRMS) method is described for the simultaneous and quantitative detection of triazines and triazoles in grapes. The analytes were detected reproducibly with high mass accuracy (mass error within 5 ppm) and further confirmed by collision-induced dissociation fragmentation in tandem MS. The LODs and LOQs for all the analytes were found to be in the nanogram per gram level (15-20 ng/g LOQ). Internal standard-normalized high-resolution accurate mass-extracted (HR-AM) peak intensities of the detected ions were used to generate the concentration response curves. Linearity (with R2 values around 0.99) was obtained for these curves within a concentration range of 20-200 ng/g of the individual analytes. The accuracy and precision of the method were further established using QC samples. Validation and performance comparison of the AP-MALDI HRMS method with an existing standard method using LC with triple quadrupole MS was carried out (evaluating sensitivity, accuracy, precision, and analysis time) using 20 table-grape field samples after QuEChERS extraction.