TY  - JOUR
A1  - Uhlig, Katja
A1  - Wischerhoff, Erik
A1  - Lutz, Jean-Francois
A1  - Laschewsky, André
A1  - Jäger, Magnus S.
A1  - Lankenau, Andreas
A1  - Duschl, Claus
T1  - Monitoring cell detachment on PEG-based thermoresponsive surfaces using TIRF microscopy
N2  - Recently, we introduced a thermoresponsive copolymer that consists of oligo(ethylene glycol) methacrylate (OEGMA) and 2-(2- methoxyethoxy) ethyl methacrylate (MEO(2)MA). The polymer exhibited an LCST at 35 degrees C in PBS buffer and was anchored onto gold substrates using disulfide polymerisation initiators. It allows the noninvasive detachment of adherent cells from their substrate. As the mechanisms that determine the interaction of cells with such polymers are not well understood, we employed Total Internal Reflection Fluorescence (TIRF) microscopy in order to monitor the detachment process of cells of two different types. We identified contact area and average cell-substrate distance as crucial parameters for the evaluation of the detachment process. The sensitivity of TIRF microscopy allowed us to correlate the specific adhesion pattern of MCF-7 breast cancer cells with the morphology of cell deposits that may serve as fingerprints for a nondestructive characterisation of live cells.
Y1  - 2010
UR  - http://www.rsc.org/Publishing/Journals/sm/index.asp
U6  - https://doi.org/10.1039/C0sm00010h
SN  - 1744-683X
ER  - 
TY  - JOUR
A1  - Uhlig, Katja
A1  - Madaboosi, Narayanan
A1  - Schmidt, Stephan
A1  - Jäger, Magnus S.
A1  - Rose, Jürgen
A1  - Duschl, Claus
A1  - Volodkin, Dmitry V.
T1  - 3d localization and diffusion of proteins in polyelectrolyte multilayers
JF  - Soft matter
N2  - The interaction of diverse biomaterials with surfaces is more crucial than ever for biomedical applications to ensure efficiency and reproducibility. Very interesting surface materials are micrometer-thick polyelectrolyte multilayers. Not only their surface but also the bulk can be loaded with biomaterials like proteins or DNA for various purposes. Therefore, we established a method to analyze the lateral and vertical distribution of fluorescently labelled proteins of various size and charge in polyelectrolyte films composed of poly(L-lysine) and hyaluronic acid by confocal laser scanning microscopy. This approach enables us to measure the diffusion coefficients of the proteins via fluorescence recovery after photobleaching as a function of their vertical position in the film and facilitates the understanding of molecular interactions in the film with a high resolution in both space and time. As a result, we confirm that protein loading in the film is driven by electrostatic interactions - uncharged dextran molecules of 10 and 500 kDa do not diffuse into the film. Proteins of different sizes (3-11 nm) can diffuse relatively fast (D = 2-4 mm(2) s(-1)) independent of their net charge, indicating complex interpolymer interactions. This approach is a new powerful experimental tool to design the polyelectrolyte multilayers for bio-applications by finding a relationship between intermolecular interactions and mobility and availability of biomolecules to biological samples (e.g. cells) or detection units (e.g. biosensors).
Y1  - 2012
U6  - https://doi.org/10.1039/c2sm26500a
SN  - 1744-683X
VL  - 8
IS  - 47
SP  - 11786
EP  - 11789
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -