Localized Surface Plasmon Resonance Imaging to Detect Protein Secretions from a Single Cell

Begin with a glass sensor chip featuring functionalized gold nanostructured arrays with a self-assembled monolayer containing carboxyl groups.

Secure the chip within a microfluidic assembly and introduce a linker, to activate the carboxyl groups.

Add peptide ligands, conjugating with the activated carboxyl groups via linkers.

Treat with a deactivator compound-containing buffer, deactivating non-specific binding sites, and wash with a buffer.

Focus a polarized light onto the chip. Using a localized surface plasmon resonance imaging system, obtain an image of the arrays — appearing as bright squares against a dark background.

At the resonance angle, the gold electrons absorb the light. Measure the reflected light intensity at the corresponding angle, to generate the sensor response.

Introduce protein-secreting hybridoma cells, which bind to the chip and wash.

The attached cells secrete proteins that interact with the ligands on the nearby array.

These interactions alter the reflected light's angle and intensity, resulting in a change in sensor response, confirming the secretory activity of cells.