Professor Niels B. Larsen, DTU Nanotech, Department of Micro- and Nanotechnology, Danish Technical University, Kgs. Lyngby, Denmark

Guided Attachment of Proteins and Cells on Polymers by Patterned Photochemistry

Micropatterning of proteins and cells on polymer surfaces are of great utility for biomolecular analysis and advanced cell culture. The technology challenge to achieve this aim is two-fold: (1) non-specific protein or cell attachment should be limited by a background layer exhibiting low adsorption of all proteins, and (2)active proteins enabling bioanalysis or promoting cell attachment should be immobilized at the intended surface locations with high positional accuracy. Photochemistry is an attractive base technology for both steps, as patterning may be performed with high resolution and the process can be performed in both open and closed transparent (micro-)systems.

Here, we will present simple procedures to perform both steps using commercially available chemistry. First, a nanometer thick base coating of low-protein binding poly(ethylene glycol) (PEG) is shown to be covalently photoimmobilized on a range of polymer substrates. Second, the coated polymer surfaces are used as substrates for homogeneous or micropatterned photoimmobilization of a number of protein classes including albumin (serum protein), IgG (antibody), alkaline phosphatase (enzyme), and fibronectin (cell adhesive) . The photoimmobilized PEG and protein coatings can be applied on open polymer surfaces and within closed microfluidic channels with equal success. Proteins on the resulting substrates are demonstrated to retain their functionality in analytical (sandwich ELISA-type) assays as well as for the spatial micropatterning of cultured human cells.