Biomimetic Liquid Crystal Cilia and Flagella
Round 1
Reviewer 1 Report
In this review, the authors focused on reviewing the progress made in simulating natural cilia and flagella using liquid crystal polymers. The authors discussed the progress made in the imitation of natural cilia and flagella using liquid crystal polymers using methods such as fiber stretching, additive manufacturing or copy molding, and also paid additional attention to the appearance of asymmetric and out-of-plane movements. The authors begin their review with a description in the introduction of what cilia and flagella are. Pointing to the fact that, by and large, cilia and flagella are the same thing, but at the same time, they should be distinguished, since flagellar cells contain only one or several flagella, while ciliated cells can be covered with many cilia. Protozoa such as paramecia often rely on the collective and coordinated beating of tubular cilia or flagella for their transport. While a surface coated with active silica is capable of transporting cargo if the cilia beat collectively and in a coordinated manner. This unidirectional transfer becomes possible due to the asymmetry in the structure of the beating of the cilia, which causes a unidirectional flow in the liquid medium surrounding the cilia. Further, the authors of the review analyze the asymmetry in the structure of the beating of the cilia, which causes a unidirectional flow in a liquid medium. Further, the authors of the review turn to liquid crystal polymers (LCPs), since these materials are given considerable attention due to their sensitivity to a wide range of environmental influences, while maintaining significant mechanical strength. The authors of the review note that for the manufacture of artificial liquid crystal cilia and flagella, the most common are forming copies and pulling fibers, since the shape of structures obtained using these methods can exactly match the shape of natural cilia / flagella.
The second chapter of the review is devoted to artificial liquid crystal flagella, as well as active down or stretched fibers. Various methods of stabilizing the shapes of linear chains of conventional liquid crystal monomers containing several (LCD oligomers) or many (linear LCD polymers) repeating links are described.
Chapter 3 is devoted to artificial liquid crystal cilia, which describes procedures for reducing the size and distance between them. It is known that the natural cilia and flagella have a width of only a few hundred nanometers, and the length, in some cases, usually ranges from 2-15 microns to more than 2 mm. These sizes are difficult to obtain using (manual) fiber drawing methods, so various processing methods are considered to reduce the size of the element. And chapter 3 is devoted to the description of various methods of reducing the size and distance.
The proposed review is undoubtedly of interest both for researchers working in this field and for those who would like to get acquainted with this direction in materials science.
The review undoubtedly deserves to be published in the journal Polymers.
Reviewer 2 Report
The manuscript represents an excellent review on recent advances related to biomimetic liquid crystal cilia and flagella. The level of novelty is high. The technical quality of the manuscript is high. The manuscript clearly represents the state-of-the-art in the specific field of research and will be of high interest to those working in the specific field of research. This impact of this work is high and I expect it will be highly cited if published. With pleasure I can recommend this manuscript for publication as it is.
