We report a label-free infrared surface plasmon biosensor with a double-chamber flow cell for continuous monitoring of morphological changes in cell culture exposed to various stimuli. In this technique, the monolayer of cultured cells is divided into two halves by a barrier, allowing the treatment of one half while the other serves as control. We demonstrate the advantages of this setup in test experiments that track kinetics of the IEC-18 cell layer response to variations in extracellular Ca2+ concentration. The sensitivity of the presented method was found to be an order of magnitude higher compared to the single-chamber biosensor.
Cell morphology is often used as a valuable indicator of the physical condition and general status of living cells. We demonstrate a noninvasive method for morphological characterization of adherent cells. We measure infrared reflectivity spectrum at oblique angle from living cells cultured on thin Au film, and utilize the unique properties of the confined infrared waves (i.e., surface plasmon and guided modes) traveling inside the cell layer. The propagation of these waves strongly depends on cell morphology and connectivity. By tracking the resonant wavelength and attenuation of the surface plasmon and guided modes we measure the kinetics of various cellular processes such as (i) cell attachment and spreading on different substrata, (ii) modulation of the outer cell membrane with chlorpromazine, and (iii) formation of intercellular junctions associated with progressive cell polarization. Our method enables monitoring of submicron variations in cell layer morphology in real-time, and in the label-free manner.
The cell morphology is a valuable indicator of the physical condition and general status of the cell. Here we demonstrate
a methodology for noninvasive biosensing of adherent living cells. Our method is based on infrared reflection
spectroscopy of living cells cultured on thin Au film. To characterize cell morphology we utilized the unique properties
of the infrared surface plasmon (λ=1-3 μm) and infrared guided wave that travel inside the cell monolayer. We
demonstrate that our method enables monitoring of submicron variations in cell morphology in real-time and in a labelfree
manner. In addition to morphological characterization, our method allows investigation of chemical composition
and molecular structure of cells through infrared absorption spectroscopy analysis.
Poly(vinylidenefluoride) film (PVDF) doped with Eu(III)(NO3)3(o-Phenanthroline)2 complex (complex A) was manufactured using an extrusion technique. Emission spectrum of the film was compared to spectra of the dopant and polyethylene based film. Stretching the film resulted in a sharp growth of intensity and reshaping of the luminescence spectrum. The impact of the PVDF matrix on the photoluminescence spectra of complex A is attributed to the Stark effect. Reasons for the increase of luminescence intensity are discussed. Quantum chemical calculations revealed a marked longwave shift of the lowest triplet and singlet energy levels of complex A compared to free phenanthroline. The amplification and frequency shifting of the luminescent spectrum of europium-complex-doped PVDF may lead to promising applications.
The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene-based film and polypropylene-based rod both doped with these complexes were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)-thenoyltrifluoroacetone-1,10-phenanthroline complex (Eu(III)) and Eu(III)-La(III)-1,10-phenanthroline complex (Eu(III)-La(III)). Comparison was made between these samples regarding absorption, excitation, emission and a lifetime of luminescence. Dependence of emission intensity on the excitation energy was determined. Emission spectra of the films were studied at room and helium temperatures. Optical properties of Eu(III) samples are different from Eu(III)-La(III) samples. Significant difference in spectra of these two types of samples may be attributed to the La(III) action.