DNA nanoscience: from prebiotic origins to emerging nanotechnology, by Kenneth Douglas, Boca Raton, CRC Press, 2016, 424 p., £45 ($58, 52 Euro) (Paperback), ISBN-10:1498750125

The scientific content of the book written by Kenneth Douglas, DNA Nanoscience: From Prebiotic Origins to Emerging Nanotechnology, is distributed over two parts, unequal in volume, content and scientific value. The first, most significant part, DNA nanotechnology, is the one to which the larger part of the book is dedicated. One can here point out the excellent description of Nadrian С. Seeman’s scientific path (including his photo), who has theoretically substantiated in 1982 the opportunity of creation of a new scientific direction – DNA structural nanotechnology. In the book, the numerous examples of creating linear and spatial DNA nanostructures (nano-DNAs), experimentally implemented by Nadrian С. Seeman, his colleagues and followers, are presented. These results are well known, published in plenty of papers in various journals; however, in the present case, they form a magnificent ornament of the book. This part of the book is most reasonable, invokes the greatest interest and, in general, illustrates the ways of further development of this scientific direction.

The second part of the book, the one which takes up much less volume, but has major philosophical value, is dedicated to the treatment of a problem and discussion which in the world literature began after the small booklet by O. Lehman, Flüssige Kristalle and die Theorien des Lebens (Leipzig, 1906). It is based on the contents of his previous two lectures (1904). (The title of this booklet determines the essence of a problem considered by Kenneth Douglas.) Since that time, the problem of correlation between the structure of chemical and biological substances and the originating of prebiotic compounds was discussed in many issues published in different countries.

The problem on the liquid-crystalline (mesophase) nature of biological structures was discussed in sessions of the Faraday society in 1933 and was the subject of discussion during the First International Conference on Liquid Crystals in 1965 at Kent University.

In 1979, G.H. Brown and J.J. Wolken published the book Liquid Crystals and Biological Structures (Academic Press, New York, San Francisco, London), attempting to find out what relation there exists between biological structures and living processes and the properties and various forms of liquid crystals.

This problem was surveyed also in the very interesting book by A. Lima-de-Faria, Evolution without Selection Form and Function by Autoevolution (Elsevier, Amsterdam, New York, Oxford, 1988).

It is necessary to add that in Russia the two-volume book written by A.C. Sonin, Liquid Crystals: The First Hundred Years (Мoscow, LELAND, 2015) was published, in which not only the contribution of scientists from various countries made to the science and development of different types of liquid crystals was described, but also liquid crystals of nucleic acids.

Rather recently, two books written by Yu. M. Yevdokimov et al., DNA Liquid-Crystalline Dispersions and Nanoconstructions (CRC Press, Taylor & Francis group, Boca Raton, London, New York, 2011) and Nanostructures and Nanoconstructions Based on DNA (CRC Press, Taylor & Francis group, Boca Raton, London, New York, 2012) were published, in which the attempt was made not only to link the properties of lyotropic liquid crystals based on linear and circular double-stranded DNA molecules to their biological functions, but also with an opportunity of creating applicationally significant nanoconstructions on the basis of DNA liquid crystals. The books contain a substantial bibliography and demonstrate that there are various methods of obtaining DNA lyotropic liquid crystals and DNA liquid-crystalline dispersions. In case of high-molecular-mass, double-stranded DNA (molecular mass larger than 10 × 10⁶ Da), different spatial patterns can be formed [1]. It is conditioned by the combination of several circumstances. The flexibility of high-molecular-mass DNA determines an opportunity of an intramolecular collapse of simple DNA molecules (so-called polymer-salt-induced (ψ) condensation). As a result of this process, the toroid-like single DNA particles are formed [2–5]. The flexible, adjacent high-molecular-mass DNA molecules can form aggregates, that is, spatial patterns consisting of sets of molecules, for which, according to the definition of P. Flory [6], there is not only three-dimensional but also one-dimensional order. At last, the separate fragments of adjacent high-molecular-mass DNA molecules can interact with one another and locally be ordered forming spatial patterns having local properties of liquid-crystalline (mesophase) and even crystalline structures.

The embodiment of the above-mentioned processes depends on the concentration of high-molecular-mass DNA and the rate of its increasing kinetics of transition of these molecules from a state of a statistical coil in a linear state, efficacy of ‘recognition’ of adjacent segments of DNA molecules and also on properties of the water–salt solution, in which the DNA molecules are dissolved.

Besides, for observation of specific textures of phases formed as a result of DNA concentration, long periods of time (days or even weeks) are demanded [7].

The behaviour of semi-rigid, linear, low-molecular-mass DNA (molecular mass is lower than 1 × 10⁶ Da) is more unambiguous. Such molecules will form both liquid crystals and liquid-crystalline dispersions [8].

The book of Kenneth Douglas invokes considerable additional interest, because in the text, the formation of liquid-crystalline forms by building blocks of nucleic acids, namely nitrogen bases, is described. Such nitrogen bases can form columns with vertical stacking interaction and hydrogen bonds between complementary base pairs.

Columnar structures of particular size (i.e., at particular number of the adjacent base pairs) can be achieved, corresponding to the Onsager criteria and particular concentration in solution, and can transform into a liquid-crystalline state. The description of formation and properties of obtained liquid-crystalline structures, undoubtedly, is very important, as it dilates our representations about possible processes, which can take place in ‘prebiotic (primary) broth’, and is of interest for the readers.

The problem of a probable role of columnar structures from nitrogen bases (including even ‘nano-DNA’) in a ‘primary broth’ remains without answer.

At first, it is known that for realisation of biological functions of DNA and RNA molecules, nitrogen bases should be linked by a sugar-phosphatic chain and have a particular length. The operation of these molecules and their secondary structure depends on the spatial organisation of their sugar moieties and phosphate groups [9]. Second, the liquid-crystalline form of linear DNA molecules has a very low biological activity (except for the mesophase form of plasmid DNA) [10]. Third, the condense, liquid-crystalline state of DNA, characteristic of heads of viral particles or chromosomes of primitive organisms, provides apparently only effective storage of the genetic information. Within the framework of Y. Bouligand’ plywood model for double-stranded DNA packing in dinoflagellate chromosome (the cholesteric liquid-crystalline model) [11, 12], the DNA biological potency is implemented on account of exposure of a segment, which corresponds to one ‘layer’ of this structure in an external environment (nucleoplasm), and the work of enzymes with this segment and reorganisation of the ‘layer’ into initial (starting) chromosome structure. This process is possible only if there is an unimpaired sugar-phosphate chain linking nitrogen bases, missing in a case of columnar structure considered in the book. Finally, the RNA or DNA molecules in a ‘primary broth’ should be protected from damaging activity of this ‘broth’ or chemical compounds in its composition. This means that around the RNA or DNA molecules, there should be a ‘protective’ shell from polycations isolating these molecules from the ‘broth’, that is, the external environment. The experiences on the isolation of columnar structures created by nitrogen bases, on account of their complex formation with polycations, are not described in the book. Taking into account the main physico-chemical requirements for the formation of columnar structures, such approaches to their isolation remain obscure.

Hence, in this part of the book, there are places which can originate in disputable points of view of specialists of various branches of science.

In the text, the fundamentals of many physical methods used for the analysis of structures of different compounds, including liquid crystals, and also some methods used in molecular biology are described. The book is well illustrated and contains photos and brief biographies of the prominent scientists, having provided major contributions to the investigation of nucleic acid’s structure.

Therefore, the book by Kenneth Douglas, DNA Nanoscience: From Prebiotic Origins to Emerging Nanotechnology is a particularly well-illustrated text with good explanations, useful for students and young scientists in the field. The book represents a nice introductory mix of definitions, terms, etc. used in the physical and structural chemistry of nitrogen bases and nucleic acids, and also in molecular biology.

In summary, we are convinced that this book can be of benefit to a broad audience of students and lecturers specialising in the areas of biology, physics and chemistry of nucleic acids, and possibly also to philosophers. Most probably, it will induce speculations and discussions and will stimulate the search for new approaches and ideas in the area of evolutional biology.