HAV‐Peptides Attached to Colloidal Probes Faithfully Detect E‐Cadherins Displayed on Living Cells

Cell adhesion molecules are crucial for a variety of biological processes, including wound healing, barrier formation and tissue homeostasis. One of them is E‐cadherin which is generally found at adherent junctions between epithelial cells. To identify this molecule on the surface of cells, E‐cadherin mimetic peptides with a critical amino acid sequence of HAV (histidine‐alanine‐valine) were synthesized and attached to solid‐supported membranes covering colloidal probes. Two different functionalization strategies were established, one based on the complexation of DOGS‐NTA(Ni) with a polyhistidine‐tagged HAV‐peptide and the other one relying on the formation of a HAV‐lipopeptide using in situ maleimide‐thiol coupling. Binding studies were performed to verify the ability of the peptides to attach to the membrane surface. Compared to the non‐covalent attachment via the His‐tag, we achieved a higher yield by lipopeptide formation. Colloidal probes functionalized with HAV‐peptides were employed to measure the presence of E‐cadherins on living cells either using video particle tracking or force spectroscopy. Here, human HaCaT cells were examined confirming the specific interaction of the HAV‐peptide with the E‐cadherin of the cells. Statistical methods were also used to determine the number of single‐bond ruptures and the force of a single bond. These findings may be essential for the development of novel biosynthetic materials given their potential to become increasingly relevant in medical applications. With a minimum of chemistry, we developed a tool based on functionalized colloidal probes that mimic the presence of adjacent cells detecting the presence of E‐cadherins on the cell surface. The specificity and dynamic strength of the peptide‐E‐cadherin interaction can be read out demonstrating the potential for a label‐free screening of cell surfaces.