In Situ Electrokinetic Preconcentrator for Conductive Biofluids

Author(s):  
Kai Yang ◽  
Jie Wu

To detect and identify biomolecules at its infectious dose, all sensors require a relatively long time — days or even weeks — for reliable results. This delay occurs because the collection of analyte molecules onto the sensing elements depends solely on the diffusion process of those agents to a sensor. This work seeks to enhance the transport process, and thereby significantly improve a sensor’s detection capability. This work investigates an in-situ, label-free nanoparticle (e.g. protein) preconcentrator based on a new AC electrothermal effect (ACET) that can operate even in a highly conductive solution for which current methods such as dielectrophoresis, electrophresis or electroosmosis won’t function effectively. The proposed AC electrokinetic preconcentrator is expected to significantly increase the nanoparticle counts, realizing sub-femto molar detection in real time.

2019 ◽  
Vol 55 (4) ◽  
pp. 541-544 ◽  
Author(s):  
Shuji Ye ◽  
Junjun Tan ◽  
Kangzhen Tian ◽  
Chuanzhao Li ◽  
Jiahui Zhang ◽  
...  

Coherent degenerate infrared-infrared-visible sum frequency generation vibrational spectroscopy provides a powerful label-free probe for identifying the vibrational modes that are coupled through the electronic states in situ and in real time.


2014 ◽  
Vol 10 ◽  
pp. 2903-2911 ◽  
Author(s):  
Anxo Fernández-Ferreiro ◽  
Noelia Fernández Bargiela ◽  
María Santiago Varela ◽  
Maria Gil Martínez ◽  
Maria Pardo ◽  
...  

Fluconazole was studied with two different hydrophilic cyclodextrins (hydroxypropyl-β-cyclodextrin (HPBCD) and sulfobutyl ether-β-cyclodextrin (SBECD)) for the formation of inclusion complexes. HPBCD and SBECD showed low cell cytotoxicity in human keratocytes as assessed by the label-free xCELLigence system for real-time monitoring. The fluconazole–HPBCD complex was incorporated into an ion-sensitive ophthalmic gel composed of the natural polysaccharides gellan gum and κ-carrageenan. This system showed good bioadhesive properties and effective control of fluconazole release.


The Analyst ◽  
2015 ◽  
Vol 140 (19) ◽  
pp. 6571-6578 ◽  
Author(s):  
Xiaoliang Guo ◽  
Rong Zhu ◽  
Xianli Zong

A micro-chip integrating cell positioning with in situ, real-time and long-time impedance measurement on a single cell using nano-modified measuring electrodes.


Author(s):  
Kilho Eom ◽  
Tae Yun Kwon ◽  
Jinsung Park ◽  
Sungsoo Na ◽  
Dae Sung Yoon ◽  
...  

Nanomechanical microcantilevers have enabled the sensitive label-free detection of chemical and/or biological molecules. In recent years, resonating microcantilevers have achieved the unprecedented sensitivity in detecting molecules. In this article, we review our current works on the label-free detection of biomolecules based on resonating microcantilevers. Our piezoelectric thick film microcantilevers exhibit the relatively high quality factor in a viscous liquid, indicating the potential of our cantilever to in situ biosensor applications for real-time detection of biomolecular interactions. It is shown that our microcantilevers allow the noise-free real-time monitoring of biomolecular recognitions, providing the insight into kinetics of biomolecular recognitions.


Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 632 ◽  
Author(s):  
Maiko Girschikofsky ◽  
Dimitrij Ryvlin ◽  
Siegfried Waldvogel ◽  
Ralf Hellmann

Trichlorofluoromethane was once a promising and versatile applicable chlorofluorocarbon. Unaware of its ozone-depleting character, for a long time it was globally applied as propellant and refrigerant and thus led to significant thinning of the ozone layer and contributed to the formation of the so-called ozone hole. Although production and application of this substance were gradually reduced at an early stage, we still face the consequences of its former careless use. Today, trichlorofluoromethane is released during recycling processes of waste cooling devices, traded on the black market, and according to recent findings still illegally manufactured. Here, we present an optical sensor device for real-time in-situ detection and measurement of this environmentally harmful chlorofluorocarbon. The described sensor is based on a planar Bragg grating that is functionalized with cyclodextrin derivatives and operates on the principle of a chemical sensor. In our study, the sensor is sensitized using per-methyl-, per-ethyl-, and per-allyl-substituted α -, β -, and γ -cyclodextrins as affinity materials for airborne trichlorofluoromethane. These functional coatings have been proven to be highly efficient, as an up to 400-times stronger signal deflection could be achieved compared to an identical but uncoated sensor. The presented sensor device shows instantaneous response to trichlorofluoromethane exposure, and features a limit-of-detection of less than 25 ppm, depending on the applied affinity material.


2019 ◽  
Vol 1 (11) ◽  
pp. 4268-4276
Author(s):  
Fengjuan Cao ◽  
Lie Wu ◽  
Xiaofei Zhang ◽  
Shanshan Li ◽  
Chao Wang ◽  
...  

How the dynamic changes of the surface properties of nanoparticles affect the nano-cell interaction was revealed for the first time, by in situ real-time label-free SEIRA spectroscopy at the nanoscale.


1999 ◽  
Vol 569 ◽  
Author(s):  
M. Tinani ◽  
E.A. Irene ◽  
Y.Z. Hu ◽  
S.P. Tay

ABSTRACTNiSi, with its low resistivity and wide processing window (350 - 750°C), is an attractive candidate for use as a gate contact material. In order to follow the interface reaction that leads to the formation of NiSi in real time, ellipsometry and atomic force microscopy (AFM) were used to study changes on the surface resulting from the reaction between Ni and Si for various times and temperatures, and Rutherford Backscattering spectrometry (RBS) to determine compositional changes in the forming silicides. We report that ellipsometry can be used to monitor the various Ni-Si phases forming in real time, and we have observed agglomeration of the silicide, which has been reported to occur at 1000°C, at temperatures, as low as 550°C for long time anneals.


The Analyst ◽  
2016 ◽  
Vol 141 (14) ◽  
pp. 4293-4298 ◽  
Author(s):  
Haibo Zhou ◽  
Qiqin Wang ◽  
Detian Yuan ◽  
Jinyong Wang ◽  
Yang Huang ◽  
...  

Early apoptosis real-time detection by label-free SERS based on externalized phosphatidylserine usingin situsynthesized silver nanoparticles.


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