While retaining its lamellar liquid crystal phase, K4Nb6O17 nanosheets were used as a template to sandwich and stabilize an alkylpoly(ethylene oxide) nonionic surfactant-water system showing monodomain (lamella) formation within the inorganic niobate sheets that appears to be not dependent on the surfactant liquid crystalline state in solution but more its concentration.

Exploring the interaction of nucleic acids with clay minerals is important to understand such issues as the persistence in soils of biomolecules and the appearance of genetic polymers in prebiotic environments. Colloidal dispersions of double stranded DNA and clay nanosheets may also provide interesting model systems to study the statistical physics of mixtures of semi-flexible rods and plates. Here, we show that adding very small amounts of DNA to liquid-crystalline montmorillonite and beidellite smectite clay suspensions strongly widens the isotropic/nematic phase coexistence region. Moreover, a spectroscopic study shows that, upon DNA addition, the first DNA molecules adsorb onto the clay particles. Remarkably, synchrotron small-angle X-ray scattering experiments reveal that the average distance between the clay sheets, in the nematic phase at coexistence, decreases with increasing DNA concentration and that the inhibition of swelling by DNA becomes almost independent of clay concentration. We interpret this DNA-mediated attraction between clay nanosheets by bridging conformations of DNA strands (plates on a string structure). In addition to bridging, DNA chains can form “loops” between sections adsorbed on the same particle, giving rise to sheet repulsions due to protruding loops. This interpretation agrees with the observed inter-clay spacings being dependent only on the DNA concentration.

This paper considers a problem of detecting nanosheets which are moving in colloidal liquid from confocal laser scanning microscopy (CLSM) images. Introducing the deep learning approach, we particularly develop a scheme for constructing the so-called `detection map’ consisting of the brightness value information on the area of nanosheets in CLSM images. Therein, we use an architecture of deep learning network ‘U-net’ and present how to implement such a network. The performance is demonstrated by some experimental studies.

A single stranded DNA (ssDNA) labeled with fluorescein isothiocyanate (FITC) was grafted on hexaniobate nanosheets as confirmed by infrared spectra, X-ray diffraction, and confocal laser scanning microscopy; this is the first case that a ssDNA was grafted on nanosheets. The grafted ssDNA retained the capability of hybridization with complementary ssDNA to form double stranded DNA so that the fluorescence of FITC was effectively quenched by hybridization with the target ssDNA having a quencher moiety.