Designing a Light-based Communication System with a Biomolecular Receiver

TL;DR

This paper introduces a communication system using the light-gated ion channel Channelrhodopsin-2 (ChR2), which causes an ion current to flow in response to light, and shows that the data rate scales up with the number of receptors, indicating that high-speed communication may be possible.

Abstract

Biological systems transduce signals from their surroundings in numerous ways. This paper introduces a communication system using the light-gated ion channel Channelrhodopsin-2 (ChR2), which causes an ion current to flow in response to light. Our design includes a ChR2-based receiver along with encoding, modulation techniques and detection. Analyzing the resulting communication system, we discuss the effect of different parameters on the performance of the system. Finally, we discuss its potential design in the context of bio-engineering and light-based communication and show that the data rate scales up with the number of receptors, indicating that high-speed communication may be possible.

Figures (16)

• Figure 1: Block diagram of our proposed model. The transmitter consists of an encoder, modulator, and light source, whereas on the receiver side, a photoreceptor, channelrhodopsin, is used, followed by the transducer and decoder. Figure adapted from idris2019visible.
• Figure 2: Three state model: (a) closed/ground state $C1$, open state $O2$ and desensitized/intermediate state $D3$. $q_{12}x(t)$, $q_{23}$ and $q_{31}$ are transition rates from transition matrix \ref{['eqn:transition matrix']} where x(t) is light intensity (b) ChR2 symbol showing that light changes its state from closed to open. Figure adapted from nikolic2009photocycles.
• Figure 3: State combination example:(a) Input $x_{i}(t)$ causes state changes which is measured in interval of time $\Delta t$, output $yi$ is detected after observing each output after sampled interval,(b) is an example of state combinations of ChR2
• Figure 4: Three ChR2 receptors for illustration. (a) All receptors are in closed states (b) After illumination of blue light, two receptors are open (c). Only one receptor is open.
• Figure 5: Directed graph showing possible states and their transition probabilities between states when there are two receptors.