DNA-Lysozyme Nanoarchitectonics: Quantitative Investigation on Charge Inversion and Compaction

2D Materials Nanoarchitectonics for 3D Structures/Functions

It has become clear that superior material functions are derived from precisely controlled nanostructures. This has been greatly accelerated by the development of nanotechnology. The next step is to assemble materials with knowledge of their nano-level structures. This task is assigned to the post-nanotechnology concept of nanoarchitectonics. However, nanoarchitectonics, which creates intricate three-dimensional functional structures, is not always easy. Two-dimensional nanoarchitectonics based on reactions and arrangements at the surface may be an easier target to tackle. A better methodology would be to define a two-dimensional structure and then develop it into a three-dimensional structure and function. According to these backgrounds, this review paper is organized as follows. The introduction is followed by a summary of the three issues; (i) 2D to 3D dynamic structure control: liquid crystal commanded by the surface, (ii) 2D to 3D rational construction: a metal-organic framework (MOF) and a covalent organic framework (COF); (iii) 2D to 3D functional amplification: cells regulated by the surface. In addition, this review summarizes the important aspects of the ultimate three-dimensional nanoarchitectonics as a perspective. The goal of this paper is to establish an integrated concept of functional material creation by reconsidering various reported cases from the viewpoint of nanoarchitectonics, where nanoarchitectonics can be regarded as a method for everything in materials science.

Lysozyme: A Natural Product with Multiple and Useful Antiviral Properties

Lysozyme, especially the one obtained from hen's egg white, continues to show new pharmacological properties. The fact that only a few of these properties can be translated into therapeutic applications is due to the lack of suitable clinical studies. However, this lack cannot hide the evidence that is emerging from scientific research. This review for the first time examines, from a pharmacological point of view, all the relevant studies on the antiviral properties of lysozyme, analyzing its possible mechanism of action and its ability to block viral infections and, in some cases, inhibit viral replication. Lysozyme can interact with nucleic acids and alter their function, but this effect is uncoupled from the catalytic activity that determines its antibacterial activity; it is present in intact lysozyme but is equally potent in a heat-degraded lysozyme or in a nonapeptide isolated by proteolytic digestion. An analysis of the literature shows that lysozyme can be used both as a disinfectant for raw and processed foods and as a drug to combat viral infections in animals and humans. To summarize, it can be said that lysozyme has important antiviral properties, as already suspected in the initial studies conducted over 50 years ago, and it should be explored in suitable clinical studies on humans.

Materials Nanoarchitectonics at Dynamic Interfaces: Structure Formation and Functional Manipulation

The next step in nanotechnology is to establish a methodology to assemble new functional materials based on the knowledge of nanotechnology. This task is undertaken by nanoarchitectonics. In nanoarchitectonics, we architect functional material systems from nanounits such as atoms, molecules, and nanomaterials. In terms of the hierarchy of the structure and the harmonization of the function, the material created by nanoarchitectonics has similar characteristics to the organization of the functional structure in biosystems. Looking at actual biofunctional systems, dynamic properties and interfacial environments are key. In other words, nanoarchitectonics at dynamic interfaces is important for the production of bio-like highly functional materials systems. In this review paper, nanoarchitectonics at dynamic interfaces will be discussed, looking at recent typical examples. In particular, the basic topics of "molecular manipulation, arrangement, and assembly" and "material production" will be discussed in the first two sections. Then, in the following section, "fullerene assembly: from zero-dimensional unit to advanced materials", we will discuss how various functional structures can be created from the very basic nanounit, the fullerene. The above examples demonstrate the versatile possibilities of architectonics at dynamic interfaces. In the last section, these tendencies will be summarized, and future directions will be discussed.

Dynamic Light Scattering of DNA-Ligand Complexes

Dynamic light scattering (DLS) enables the characterization of sizes and electrokinetic properties of colloids, polymers, and macromolecules. DNA is a charged semiflexible polyelectrolyte that is condensed or compacted by counterions, proteins, and other condensing agents in processes such as chromosome compaction and gene therapeutic applications. DNA condensation is closely related to charge screening since packaging requires effective neutralization of its surface negative charges. In this chapter, we describe in detail the protocol for DLS DNA-ligand complexes. As an example, we describe data for the condensation of DNA by chitosan and the measurement of size, zeta potential, and electrophoretic mobility of the DNA-ligand complex by DLS.

Locally Denatured DNA Compaction by Divalent Cations

The denaturation of DNA is a critical process in biology and has many biotechnological applications. We investigated the compaction of locally denatured DNA by a chemical denaturation agent, dimethyl sulfoxide (DMSO), using magnetic tweezers (MTs), atomic force microscopy (AFM), and dynamic light scattering (DLS). Our results show that DMSO not only is capable of denaturing DNA but also able to compact DNA directly. When the DMSO concentration is above 10%, DNA condensation occurs due to the reduction in the persistence length of DNA and excluded volume interactions. Meanwhile, locally denatured DNA is easily condensed by divalent cations, such as magnesium ions (Mg²⁺), contrasting with no native DNA condensation by the classical divalent cations. Specifically, the addition of more than 3 mM Mg²⁺ to a 5% DMSO solution leads to DNA condensation. The critical condensing force (F_C) increases from 6.4 to 9.5 pN when the Mg²⁺ concentration grows from 3 to 10 mM. However, F_C decreases gradually with a further increase in Mg²⁺ concentration. For 3% DMSO solution, above 30 mM Mg²⁺ is needed to compact DNA and a weaker condensing force was measured. With increasing Mg²⁺ concentration, the morphology of the DMSO partially denatured DNA complex changes from loosely random coils to a dense network structure, even forming a spherical condensation nucleus, and finally to a partially disintegrated network. These findings show that the elasticity of DNA plays an important role in its denaturation and condensation behavior.

Encapsulation of Folic Acid and α-Tocopherol in Lysozyme Particles and Their Bioaccessibility in the Presence of DNA

Protein particles have been reported as the potential carriers for the co-encapsulation of bioactive components. In this study, lysozyme, a basic protein, was used to simultaneously encapsulate folic acid and α-tocopherol at pH 4.0. The encapsulation efficiency and loading capacity of folic acid or α-tocopherol increased with its respective concentration. Folic acid had no influence on the encapsulation of α-tocopherol. However, the encapsulation of folic acid was improved by α-tocopherol below 40 μg/mL but reduced by α-tocopherol at higher concentrations. The encapsulation by lysozyme shielded folic acid, α-tocopherol, or both partially from the attack of 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical cation. No masking effect of lysozyme encapsulation on α-tocopherol was found in DPPH antioxidant activity assay. Furthermore, the DNA coating was used to improve the dispersion of lysozyme with folic acid and α-tocopherol. The lysozyme/DNA particles with folic acid and α-tocopherol showed a homogenous size distribution of 180-220 nm with ζ-potential values between -33 and -36 mV. The release and bioaccessibility of folic acid in lysozyme/DNA with α-tocopherol were similar to that of folic acid alone, while the release of α-tocopherol was delayed and its bioaccessibility was improved by encapsulation in lysozyme/DNA with folic acid. The data gathered here would provide guidance for the use of lysozyme-based co-encapsulating carriers in the development of functional foods.

DNA Penetration into a Lysozyme Layer at the Surface of Aqueous Solutions

The interactions of DNA with lysozyme in the surface layer were studied by performing infrared reflection-absorption spectroscopy (IRRAS), ellipsometry, surface tensiometry, surface dilational rheology, and atomic force microscopy (AFM). A concentrated DNA solution was injected into an aqueous subphase underneath a spread lysozyme layer. While the optical properties of the surface layer changed fast after DNA injection, the dynamic dilational surface elasticity almost did not change, thereby indicating no continuous network formation of DNA/lysozyme complexes, unlike the case of DNA interactions with a monolayer of a cationic synthetic polyelectrolyte. A relatively fast increase in optical signals after a DNA injection under a lysozyme layer indicates that DNA penetration is controlled by diffusion. At low surface pressures, the AFM images show the formation of long strands in the surface layer. Increased surface compression does not lead to the formation of a network of DNA/lysozyme aggregates as in the case of a mixed layer of DNA and synthetic polyelectrolytes, but to the appearance of some folds and ridges in the layer. The formation of more disordered aggregates is presumably a consequence of weaker interactions of lysozyme with duplex DNA and the stabilization, at the same time, of loops of unpaired nucleotides at high local lysozyme concentrations in the surface layer.

Tracking Heme-Protein Interactions in Healthy and Pathological Human Serum in Native Conditions by Miniaturized FFF-Multidetection

The interaction of heme with blood serum proteins plays an important role in many physiological and pathological processes involving enzyme activity, gene expression and cell proliferation. The mechanisms underlying these interactions are; however, not yet fully understood. New analytical methods able to investigate protein-heme binding in native, biologically representative conditions are thus required. In this work, we present a method based on miniaturized, hollow-fiber flow field-flow fractionation with multiple spectrophotometric and light-scattering detection for size separation of high-abundance serum proteins and selective detection of heme-bound subpopulations. Heme is found to mainly interact with serum albumin, whereas a low amount also binds to other proteins such as IgM. The ability to bind heme in physiological conditions is also investigated for individual serum proteins. IgG is found unable to bind heme at clinically relevant concentrations. The proposed method allows separation, quantitation, and mass/size characterization of serum high-abundance proteins, providing information of heme-protein complex stability and preferred heme-clearing pathways. The same approach could be in perspective extended to the investigation of specific heme-antibody binding, and to further studies involving other molecules of pharmaceutical/clinical interest.