Juul Kusk (kendosheep48)

Rapid yet accurate detection of disease-related biomarkers is key for point of care testing, where there is an increasing demand for multi-index analysis. Here, we present a versatile device for multianalyte quantification based on the microfluidic technique and electrochemical sensor array. The analytes were shunted through inner-built channels to screen-printed electrodes installed at different positions of the chip. These electrodes were modified with different nanomaterials and sensing agents to afford specific responses to the corresponding indicators. To prove the applicability of the platform for multifunction, we chose leukemia as the model disease and determined four relevant markers methotrexate (MTX), lactate dehydrogenase (LDH), uric acid (UA), and urea. They are indicative as/for the therapeutic drug (MTX), prognosis (LDH), and side effect (UA and urea). The sensing chip exhibited low detection limits of 35 nM, 25 U/L, 450 nM, and 20 μM toward the four analytes, which are much lower than their minimum contents in human serum. Furthermore, practical application of the chip was demonstrated by simultaneous detection of the four analytes in the blood plasma of rabbit. By simply replacing the modification agents, the sensing platform is expected to serve the detection of a wide range of chem/biosubstances in various fields.Upconversion nanoparticles (UCNPs) have potential applications in biosensing and bioimaging. However, the UCNPs-based sensors constructed by luminescence resonance energy transfer (LRET) always suffer from low quenching efficiency, hindering their application. Therefore, exploring a new strategy to resolve this issue is highly desirable. Herein, a strategy based on the surface plasmon resonance (SPR) effect of gold nanorods (AuNRs) is presented. The luminescence of UCNPs was modulated by adjusting the SiO2 thickness of AuNRs@SiO2 and the structure of UCNPs; an enhancement factor of ≈50 times was obtained. Based on the results of the SPR effect of AuNRs, we designed two kinds of potential upconversion microRNA sensors using microRNA-21 as a model to resolve the problem of the lower quenching efficiency resulting from a dye as a quencher. Studies revealed that the proposed strategy could be successfully used to construct upconversion microRNA sensors for avoiding the limitation of the low quenching efficiency. The sensitivity was ≈10 000 times higher than that of the upconversion sensor using dyes as quenchers. Importantly, the assay of microRNA-21 was successfully achieved using this sensor in human serum samples and human breast cancer cell (MCF-7) lysates. It provides a new method for designing upconversion microRNA sensors and may have potential for use in biosensing and bioimaging.Inertial microfluidics is a promising approach for particle separation because of the superior advantages of high throughput, simplicity, precise manipulation, and low cost. However, the current obstacle of inertial microfluidics in biological applications is the broad size distribution of biological microparticles. Most devices only work well for a narrow range of particle sizes. For focusing and separating a new set of particles, troublesome and time-consuming design, fabrication, testing, and optimization procedures are needed. As such, it is of particular interest to design a microfluidic device that can be tuned and adjusted to separate particles of various sizes. This paper reports on the proof of concept for a stretchable microfluidic device that can control the length via a stretching platform. By changing the channel dimensions, the device can be adapted to different particle sizes and flow rate ratios. We successfully demonstrate this approach with the separation of a mixture of 10 and 15 μm particles. Stretching the device significantly improves the focusing and separation efficiency of the specific particle sizes. We also show that there is an optimum stretching length, which results in the best separation