Giant Enhancement of Raman Scattering by a Hollow-Core Microstructured Optical Fiber Allows Single Exosome Probing.

Microstructured optical fibers (MOFs) provide solutions for breaking through the bottlenecks in areas of high-power transmission and high-efficiency optical waveguides. Other than transporting light waves, MOFs can synergistically combine microfluidics and optics in a single fiber with an unprecedented light path length not readily achievable by planar optofluidic configurations. Here, we demonstrate that hollow-core anti-resonant optical fibers (HcARFs) can significantly enhance Raman scattering by over three orders of magnitude (EF ≈ 5000) compared with a planar setup, due to the joint mechanisms of strong light-matter interaction in the fiber core and the cumulative effect of the fiber. The giant enhancement enables us to develop the first optical fiber sensor to achieve single cancer exosome detection via a sandwich-structured strategy. This enables a multiplexed analysis of surface proteins of exosome samples, potentially allowing an accurate identification of the cellular origin of exosomes for cancer diagnosis. Our findings could expand the applications of HcARF in many exciting areas beyond the waveguide.

Microstructured Optical Fiber-Enhanced Light-Matter Interaction Enables Highly Sensitive Exosome-Based Liquid Biopsy of Breast Cancer.

Exosome-based liquid biopsies highlight potential utility in diagnosis and determining the prognosis of patients with cancer and other diseases. However, the existing techniques are severely limited for practical applications due to the complications of high cost, low sensitivity, tedious procedures, and large sample consumption. Herein, we report a microstructured optical fiber sensor for fast, sensitive, and accurate quantification of exosomes in blood samples of breast cancer patients. Numerical simulations are applied to demonstrate that hollow-core microstructured antiresonant fibers (HARFs) can stringently confine light in the fiber core, ensuring strong light-matter interaction and thus maximumly amplifying the signal. Taking this advantage, a AuNPs-dsDNA assembly containing gold nanoparticles, a recognizing DNA aptamer, and a fluorescent reporter DNA sequence is fabricated followed by immobilization on the fiber wall to form a AuNPs-dsDNA-HARF sensor. Cancer-derived exosomes can be recognized and captured in the fiber channel and generate dose-dependent fluorescent signals for quantification. The microfiber sensor demonstrates enhanced sensitivity and specificity, enabling the detection of single digits of exosome particles at the nanoliter sample level. In addition, by tracking exosome phenotypic changes, the proposed fiber sensor can facilitate precise drug treatment monitoring. This work provides a robust platform for exosome-based biopsy for cancer diagnosis and prediction of therapeutic outcomes.

Thermal desorption behavior of fluoroquinolones in contaminated soil of livestock and poultry breeding.

As a kind of typical veterinary drug, fluoroquinolone antibiotics (FQs) are widely used in the field of livestock and poultry breeding, but these FQs escape to surrounding soil through various pathways, polluting soil through long-term accumulation. Current study proposed a clean technology named thermal desorption to deal with FQs contaminated soils. It was observed that time, temperature and soil particle size were the critical factors in FQs thermal desorption. Results of the study showed that higher temperature was more effective in the removal of FQs, while removal of FQs attached with finer particles was more difficult compared to coarse particles. Fine soil particles (0.6-0.85 mm) were decontaminated up 99.4% when treated with 400 °C for 60min. Thermal desorption of FQs from contaminated soil was governed by first-order kinetics. Based on the detection of exhaust gas components, a possible thermal desorption mechanism was proposed. Study suggested that thermal desorption was a clean and effective remediation method to treat FQs-contaminated soils without generating any further waste.

Study on the remediation of tetracycline antibiotics and roxarsone contaminated soil.

Antibiotics are commonly used in livestock and poultry breeding along with organic arsenic. Through long-term accumulation, they can enter into the surrounding soil through various pathways and contaminate the soil. In this paper, tetracycline antibiotics (TCs) and roxarsone (ROX) contaminated soil were used as the representatives of the two kinds of veterinary drugs contaminated soil, respectively, to study the thermal desorption behavior and arsenic stabilization process. Different parameters like heating temperatures, heat duration, stabilizer type and dosage were optimized for effective removal of TCs and ROX. Furthermore, TCs and ROX removal path and ROX stabilization mechanism were explored. Results of the study showed that over 98% of tetracycline antibiotics and roxarsone were effectively removed at 300 °C for 60 min. The heat treatment process of TCs contaminated soil was controlled by the first-order kinetics. Based on the detection of degradation products and thermogravimetric analysis, the possible thermal degradation path of TCs and ROX was proposed. Addition of FeSO4.7H2O (10% by weight) as stabilizer during the heat treatment process yielded 96.7% stabilization rate. Through the analysis of arsenic fractions, valence and the characterization of soil samples collected after the heat treatment, mechanism of arsenic stabilization in ROX was explored. The results show that thermal treatment combined with chemical stabilization technology can not only degrade TCs and ROX efficiently and completely, but also convert organic arsenic into inorganic state, which is conducive to better stabilization, and finally achieve effective and safe remediation of this kind of contaminated soil.