Fig. 4: Frequency-domain analysis of a pre-equilibrium sensing system.
From: Pre-equilibrium biosensors as an approach towards rapid and continuous molecular measurements
a Slow- and fast-changing target concentration signals resolved with increasingly high-frequency content. High-frequency content is associated with fast-changing features in the waveform. A larger number of harmonics are required to resolve the sharp transitions of the fast-changing signal. b We used a sinusoidal test signal T(t) with mean concentration T0 and amplitude T1 to analyze the receptor’s frequency-domain characteristics. A receptor with fast kinetics will respond equally well to low- and high-frequency content. A receptor with slower kinetics will attenuate high-frequency content, however, resulting in a reduced fraction of target-bound receptors, y(t). To reconstruct the original target signal T(t) from the sampled response w[n], the TEA must compensate for this attenuation. Since noise introduced by the sensor will experience this amplification as well, compensation of slow-kinetics systems will also increase the contribution of noise to the target estimate.
