sensorgrams

A sensorgram is a graphical representation of data collected from a biosensor. Biosensors are analytical devices that combine a biological or biomimetic component with a physicochemical transducer. The biological component, such as an enzyme, antibody, or nucleic acid, recognizes and binds to a specific analyte. This binding event then causes a change in a physical property that is detected by the transducer. The sensorgram plots the signal output from the transducer over time.

Typically, a sensorgram displays the measured signal on the y-axis and time on the x-axis. The signal can represent various physical or chemical changes, including changes in mass, optical properties, electrical current, or heat. Different phases can be observed on a sensorgram. The baseline represents the initial stable signal before the analyte is introduced. The association phase occurs when the analyte binds to the immobilized biological element, causing the signal to rise. The steady-state phase indicates that the binding has reached equilibrium. The dissociation phase begins when the analyte is removed or a dissociating agent is introduced, leading to the release of the analyte and a decrease in the signal.

Analysis of sensorgrams allows for the determination of kinetic and affinity parameters of molecular interactions. For example, in surface plasmon resonance (SPR) experiments, sensorgrams are used to calculate association rate constants (ka), dissociation rate constants (kd), and equilibrium dissociation constants (KD), which quantify the strength and stability of the binding between molecules. These parameters are crucial for understanding biological processes and for drug discovery and development. Different types of biosensors will produce sensorgrams that reflect the specific transduction method employed.