Search

The study on cells in vitro usually encounters the signals with oscillatory or periodic temporal profiles, which requires the pulsating flow control. Aiming at this target, a novel approach to generate the pulsating waveform of fluid flow by the photothermally induced phase change in the microchannel with the sawtooth-shaped baffles was developed in this work. It was demonstrated that the periodical immobilization-motion-immobilization flow behavior was formed by the combined photothermally induced interfacial behaviors and the in-channel baffle structures, which successfully generated stable oscillating flow with good response. To further explore the pulsating flow behaviors, effects of the baffle design and input laser power were also investigated. It was shown that increasing the baffle width and interval distance between them could yield large pulse peak flow rate but low frequency, while both the pulse peak flow rate and frequency increased with the input laser power. These results indicate that via the change of the baffle design parameters and laser power, the pulse flow waveform can be well controlled for the in vitro cellular studies. [ABSTRACT FROM AUTHOR]

To realize the selective detection of 4-chlorophenol (4-CP) in water, a highly sensitive plastic optical fiber (POF) evanescent wave sensor was prepared using a D -shaped POF coated selective adsorption film of 4-CP. The film was composed of molecularly imprinted polymer (MIP) particles and PEBA2533 matrix. The MIP particles were employed to realize the selective adsorption and enrichment of 4-CP molecules, which lead to the changes in the refractive index of the MIP-PEBA2533 coating. These, in turn, resulted in changes in the light transmission in the D -shaped region and caused the attenuation of the evanescent field intensity on the surface of the sensing region. To illustrate the measurement principle, a theoretical model of the sensor was established. Furthermore, the performance parameters of the sensors, such as sensitivity, repeatability, selectivity and low limit of detection (LOD), were experimentally studied. The results highlighted that the proposed sensor exhibited a good sensitivity of -0.56 × 10-6 (μg/L)-1 and LOD of 100 μg/L for the detection of 4-CP in water. Moreover, this optic-fiber sensor has high specific recognition ability for 4-CP. The results of this study could inform the development of methods for on-line and accurate detection of 4-CP. • A plastic optic-fiber for selective detection of 4-chlorophenol was developed. • Selective adsorption molecularly imprinted polymer of 4-chlorophenol was created. • Working principle of proposed sensors was theoretically analyzed. • Sensitivity, repeatability, selectivity and low limit of detection were checked. • Proposed sensor showed high sensitivity, high selectivity, and good detection limit. [ABSTRACT FROM AUTHOR]