Quantifying interactions between cell receptors and adhesion ligand-modified polymers in solution

Specific interactions between cells and cell-interactive polymers in solution were investigated by the fluorescence resonance energy transfer (FRET) technique and rheological measurements. The green fluorescence emission was dramatically reduced when rhodamine-stained cells were mixed with a fluorescein-labeled RGD-alginate solution, compared with those mixed with no RGD-containing alginate solution, which indicated an occurrence of FRET and existence of specific interactions between the cells and the polymers in solution. Rheological measurements also confirmed the formation of ordered structures of cell/polymer mixtures, caused by specific cell-polymer interactions. The FRET method was able to provide a useful means of investigating cell-polymer interactions, both in a qualitative and quantitative manner, and this approach to monitoring and controlling specific interactions between cells and polymers could be useful in the design and tailoring of polymeric carriers for cells, as well as for biological drugs, especially for tissue engineering applications.