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Biomedical subjects

Marc Nolte

Publications and source records attributed to Marc Nolte.

4 recordsLinked to original sources
PubMed2006

Freestanding polyelectrolyte films as sensors for osmotic pressure.

Freestanding ultrathin polyelectrolyte-multilayer membranes, transferred to topographically structured polydimethylsiloxane (PDMS), are used as mechanical sensors. Due to the membranes' semipermeability, high-molecular-weight molecules can be either entrapped inside them or excluded, thus generating an osmotic pressure. This leads to a deformation. We investigate the deformation as a function of the osmotic pressure and present an analytical theory that fully describes the data. Thus, osmotic pressures can be determined quantitatively. The individual osmotic-sensitive elements have only microscopic dimensions, and arrays can be easily produced.

Chemistry, Physical↗
PubMed2005

Encapsulated living cells on microstructured surfaces.

The immobilization of cells in defined arrays (cell patterning) is a key step towards cell-based biosensors or other cell-based devices. While cell patterning is usually achieved by modifying the surface on which only the cells should adhere and leaving the cells unmodified, we present here a different approach in which cells are first coated with polyelectrolytes and subsequently immobilized on patterned surfaces. By coating, the cells are protected and their interactions with the substrate are modified such that patterning is simplified. We used microcontact printing of polyelectrolytes to structure surfaces such that regions of opposite charges and the same charge as the cell coating were present and found that we can thus achieve patterning of the coated yeast cells. In accordance with prior work, we find that coating does not kill the cells and coated GFP-expressing cells still function after immobilization, which we checked by fluorescence microscopy.

Cell Adhesion↗
PubMed2004

Microstructuring of polyelectrolyte coated surfaces for directing capsule adhesion.

We use microcontact printing (microCP) of polyelectrolytes (PEs) onto flat substrates for creating surfaces with regions of negative and positive surface charge. Subsequent incubation of these surfaces with solutions containing hollow PE capsules leads to preferential adsorption of the capsules on regions of opposite charge, while regions of like charge are passivated against adhesion. As well, adsorption of fluorescently labeled PEs is found to be directed toward oppositely charged regions at neutral pH. This approach could lead to novel functional surfaces for combinatorial chemistry or sensor applications and could also be expanded toward cell immobilization.

Adsorption↗