Microtubules as One-Dimensional Crystals: Is Crystal-Like Structure the Key to the Information Processing of Living Systems?

Each tubulin protein molecule on the cylindrical surface of a microtubule, a fundamental element of the cytoskeleton, acts as a unit cell of a crystal sensor. Electromagnetic sensing enables the 2D surface of microtubule to act as a crystal or a collective electromagnetic signal processing system. We propose a model in which each tubulin dimer acts as the period of a one-dimensional crystal with effective electrical impedance related to its molecular structure. Based on the mathematical crystal theory with one-dimensional translational symmetry, we simulated the electrical transport properties of the signal across the microtubule length and compared it to our single microtubule experimental results. The agreement between theory and experiment suggests that one of the most essential components of any Eukaryotic cell acts as a one-dimensional crystal

The Influence of the External Signal Modulation Waveform and Frequency on the Performance of a Photonic Forced Oscillator

Photonic crystals have been an object of interest because of their properties to inhibit certain wavelengths and allow the transmission of others. Using these properties, we designed a photonic structure known as photodyne formed by two porous silicon one-dimensional photonic crystals with an air defect between them. When the photodyne is illuminated with appropriate light, it allows us to generate electromagnetic forces within the structure that can be maximized if the light becomes localized inside the defect region. These electromagnetic forces allow the microcavity to oscillate mechanically. In the experiment, a chopper was driven by a signal generator to modulate the laser light that was used. The driven frequency and the signal modulation waveform (rectangular, sinusoidal or triangular) were changed with the idea to find optimal conditions for the structure to oscillate. The microcavity displacement amplitude, velocity amplitude and Fourier spectrum of the latter and its frequency were measured by means of a vibrometer. The mechanical oscillations are modeled and compared with the experimental results and show good agreement. For external frequency values of 5 Hz and 10 Hz, the best option was a sinusoidal waveform, which gave higher photodyne displacements and velocity amplitudes. Nonetheless, for an external frequency of 15 Hz, the best option was the rectangular waveform