Cell-based biosensors based on light-addressable potentiometric sensors for single cell monitoring.
ABSTRACT Cell-based biosensors incorporate cells as sensing elements that convert changes in immediate environment to signals for processing. This paper reports an investigation on light-addressable potentiometric sensor (LAPS) to be used as a possible cell-base biosensor that will enable us to monitor extracellular action potential of single living cell under stimulant. In order to modify chip surface and immobilize cells, we coat a layer of poly-L-ornithine and laminin on surface of LAPS chip on which rat cortical cells are grown well. When 10 microg/ml acetylcholine solution is administrated, the light pointer is focused on a single neuronal cell and the extracellular action potential of the targeted cell is recorded with cell-based biosensor based on LAPS. The results demonstrate that this kind of biosensor has potential to monitor electrophysiology of living cell non-invasive for a long term, and to evaluate drugs primarily.
Article: Controlled polymerization chemistry to graft architectures that influence cell-material interactions.[show abstract] [hide abstract]
ABSTRACT: Acrylate monomers were photografted from polymer substrates to create cell responsive chemically and biologically active surfaces that manipulate cell response. Three monomers, polyethylene glycol monoacrylate (MW 375 g/mol) (PEG375A), a monomeric extra-cellular matrix protein, and a cell-cleavable fluorescent monomer, were spatially photopatterned from a base substrate. The base substrate consisted of a dithiocarbamate (DTC) functionalized urethane diacrylate/tri(ethylene glycol)diacrylate copolymer and was shown to non-specifically support NIH 3T3 fibroblast cell adhesion. The DTC-containing polymer was further modified by grafting PEG375A to demonstrate selective blocking of cell-material interactions. Next, acrylated collagen type I was patterned onto polymer substrates to further promote specific cell interactions (i.e. by presenting cell-adhesive moieties). Hydrophilic PEG375A grafted patterns were shown to prevent 3T3 fibroblast adhesion to polymer in spatially grafted regions, while biologically active acrylated collagen type I promoted cell-surface interactions. Collagen type I was grafted at varying densities (0-7.5 pmol/grafted square), and the extent of cell adhesion and spreading were evaluated for each of these graft densities using fluorescence microscopy. Finally, methacrylated carboxyfluorescein diacetate (CFDA) was synthesized and photografted onto a cell-adhesive substrate as a cell sensing mechanism. The acetate groups found in the structure of CFDA cleave in the presence of cells. This cell-responsive substrate results in fluorescence indicative of acetate-group cleavage associated with cell interactions that occurs in patterned regions on polymer surfaces. Collectively, the results herein show the utility and application of a spatially and temporally controlled photografting process for designing cell responsive polymer surfaces.Acta Biomaterialia 04/2007; 3(2):151-61. · 4.86 Impact Factor