Midinfrared surface-plasmon resonance: A novel biophysical tool for studying living cells

Abstract

We discuss the Surface-Plasmon-Resonance (SPR) technique based on Fourier -Transform -In-fraRed (FTIR) spectrometry. We explore the potential of the infrared surface plasmon resonance technique for biological studies in aqueous solutions and compare it to the conventional surface plasmon technique operating in the visible range. We demonstrate that the sensitivity of the SPR technique in the infrared range is not lower and in fact is even higher. We show several examples of applying FTIR-SPR for biological studies: (i) monitoring D-glucose concentration in solution, and (ii) measuring D-glucose uptake by erythrocytes in suspension. We emphasize the advantages of infrared SPR for studying living cell cultures and show how this technique can be used for characterization of (i) cholesterol penetration into plasma membrane, and (ii) transferrin-induced clathrin-mediated endocytosis. * electronic address: golos@vms.huji.ac.il

Surface plasmon-based infrared spectroscopy for cell biosensing

“…3(a)] without losing the sensitivity (∼10 −6 RIU). 18,19,23 This allows monitoring of cellular events not only in the cell-substrate contact region but also inside basal cell region and even in the cell nucleus. The SP propagation length, L x [ Fig.…”

“…18 It means that when the analyte layer consists of the regions with different refractive indices, two separate SP resonances will appear only if the size of these regions is larger than the L x . 18 Otherwise, there will be a single SP resonance corresponding to the mean refractive index. However, even this "average" SP resonance is sensitive to morphological changes in cells (see Sec.…”

“…[4][5][6][7][8][13][14][15] We present a label-free method for cell sensing based on the infrared reflection spectroscopy. 18 We use the confined infrared waves such as surface plasmon (SP) and guided (TM) modes to study in real-time and label-free manner the structure and functioning of living cells on substrate. SP propagates at the cell/substrate interface and probes the lower (basal) part of the cell 15 while the guided modes travel inside the cell monolayer, and are sensitive to cell height and cell-cell adhesion.…”

Infrared Surface Plasmon Spectroscopy of Living Cells

“…This resulted in the powerful near-infrared surface plasmon technique with wavelength interrogation that offers several advantages over conventional SPR techniques based on angular interrogation. Recently, we extended the FTIR-SPR technique into mid-infrared range by using metallic mirrors and ZnS prism [10,11].…”

“…So far we used this technique to study alterations in membrane cholesterol levels in HeLa cells [12], de novo formation of early endocytic transport vesicles in response to transferrin internalization by human melanoma cells [13], and detection of glucose uptake by erythrocytes [11].…”