Light-powered reactivation of flagella and contraction of microtubules network: towards building an artificial cell

Abstract

Artificial systems capable of self-sustained directed movement are of high interest with respect to development of many challenging applications including medical treatments but also technical applications. The bottom-up assembly of such systems in the context of synthetic biology is still a challenging task. Here, we demonstrate the biocompatibility and efficiency of an artificial light-driven energy module and a motility functional unit by integrating light-switchable photosynthetic vesicles with demembranated flagella, thereby supplying ATP for dynein molecular motors upon illumination. Flagellar propulsion is coupled to its beating frequency and the dynamic synthesis of ATP triggered by energy of light, enabled us to control beating frequency of flagella as a function of illumination. Light-powered functionalized vesicles integrated with different biological building blocks such as bio-polymers and molecular motors may contribute to bottom-up synthesis of artificial cells that are able to undergo motor-driven morphological deformations and exhibit directional motion in a light-controllable fashion.

Time-reversal symmetric component of the flagellar beat enhances the translational and rotational velocities of isolated Chlamydomonas flagella

“…3B). In our experiments, we measured a critical minimum of ATP concentration around 60 µM was required to reactivate axonemes [26,41]. Reactivated axonemes swim on circular trajectories effectively in 2D (see Ref.…”

“…In isolated and reactivated flagella of C. reinhardtii, the following dominant modes in the waveform are observed [24][25][26]: 1) a semi-circular static mode resulting from averaging the flagellar shapes over a beat cycle, 2) a main dynamic mode describing a base-to-tip wave propagation at the fundamental beat frequency f 0 , and 3) a secondharmonic component which describes a base-to-tip wave propagation at frequency 2f 0 . The static mode and the second harmonic of the waveform contribute to the axonemal rotational velocity [27,40,41] and in the absence of these two components, the axoneme swims in a straight sperm-like trajectory [31,32]. In this work, we combined highprecision high-speed phase contrast microscopy (1000 fps) with image processing and analytical analysis to study the wave patterns of actively beating axonemes isolated from C. reinhardtii.…”

Bio-hybrid micro-swimmers propelled by flagella isolated from C. reinhardtii†

“…2B). Beating frequency of axonemes depends on ATP concentration following a Michaelis-Menten-type kinetics [23,37] with a linear trend at low amount of ATP and saturation at higher ATP concentrations around 1 mM. Following the addition of ATP, asymmetric bending waves initiate at the basal end (which is attached to a bead in Fig.…”