Nature as a Model for Mimicking and Inspiration of New Technologies

Bar‐Cohen, Yoseph

doi:10.5139/ijass.2012.13.1.1

Cited by 30 publications

(14 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An indication of the switching speed was obtained by measuring the kinetic friction coefficient during cycling of the coating between a flat and an activated jagged state. The transition from low to high friction forces suggests a switching speed of 5 s. We anticipate the use of these dynamic surfaces with variable friction and surface area for haptic applications, e.g., to provide feedback of touch input, or in robotic manipulation controlling grip and release of objects (35).…”

Section: Resultsmentioning

confidence: 99%

Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating

Liu

Onck

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

124

View full text Add to dashboard Cite

In this work we propose randomly ordered polydomain nematic liquid crystal polymer networks to reversibly generate notable jagged relief patterns at a polymer coating surface by light illumination. The domain size is controlled by the addition of traces of partly insoluble fluorinated acrylate. The photoresponse of the coating is induced by a small amount of copolymerized azobenzene monomers. Upon exposure to UV light, azobenzene undergoes trans to cis isomerization, resulting in a change in molecular order and packing within each domain. The extent of this effect and its directionality depends on the domain orientation. Localized to domain level, this morphological change forms large 3D spikes at the surface with a modulation amplitude of more than 20% of the initial thickness. The process is reversible; the surface topographical patterns erase within 10 s by stopping the light exposure. A finite element model is applied to simulate the surface topography changes of the polydomain coating. The simulations describe the formation of the topographic features in terms of light absorption and isomerization process as a function of the director orientation. The random director distribution leads to surface structures which were found to be in close agreement with the ones measured by interference microscopy. The effect of domain size on surface roughness and depth modulation was explored and related to the internal mechanical constraints. The use of nematic liquid crystal polydomains confined in a polymer network largely simplifies the fabrication of smart coatings with a prominent triggered topographic response.surface dynamics | self-organization | switchable jagged surfaces | polydomain liquid crystal polymer | light activation I n nature, living creatures have developed a series of motion and surviving strategies based on unique topographic patterns on their surfaces. The surface topographies range from static patterns as, for instance, found on the leaves of the lotus flower, repelling water and dirt particles, to the dynamic structures that appear under certain conditions as found in many mammals. An example is the pilomotor reflex at the skin of mammals which creates insulation in cold conditions and provides protection by scaring away predators when the body appears larger. To date, many studies have been devoted to the use of static surface topographies fabricated by wrinkling (1, 2), embossing (3), or lithography. However, there is an increasing demand to make these surface structures switchable in modern applications, such as adjustable gas and water flow behavior at corrugated surfaces (4), autonomously adjusting lenses (5), controlled wettability (6), and modulated optics such as scattering, diffraction, or reflection (7-9). Also, the mechanical properties can be altered by the appearance or disappearance of protrusions at the surface (10, 11), such as friction, stick, and adhesion which manifest themselves in, e.g., haptic applications (12).Our focus here is to develop dynamic topographic patterns at su...

show abstract

Section: Resultsmentioning

confidence: 99%

Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating

Liu

Onck

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

124

View full text Add to dashboard Cite

show abstract

“…Plants have offered innovative solutions to medicine, material science, architecture, robotics, and engineering and can surely further cosmetic products ( Burris et al., 2017 ; Li and Wang, 2015 ; Momeni and Ni, 2018 ; Rian and Sassone, 2014 ; Koch et al., 2009 ; Bar-Cohen, 2012 ). Plants have, for example, devised climbing strategies based on either particles or adhesive polymers that might find application to promote the interaction of the cosmetic products with the skin surface ( Burris et al., 2017 ).…”

Section: Future Developmentsmentioning

confidence: 99%

Plant Complexity and Cosmetic Innovation

Faccio

2020

iScience

View full text Add to dashboard Cite

Plants have been used in cosmetic products since ancient times and are the subject of scientific investigation even nowadays. During the years, a deeper understanding of both the behavior of skin and of plants have become available drawing increasingly complex pictures. Plants are complex organisms that produce different metabolites responding to the environment they live in. Applied to the skin, phytomolecules interact with skin cells and affect the skin well-being and appearance. Ethnobotanical studies on the one hand and physico-chemical analyses on the other have pictured a rich inventory of plants with potential to enrich modern cosmetic products.

show abstract

“…25,26 The novel products can be exploited as simplified models to deepen the knowledge of the natural macromolecular functions and as molecular tools finding applications in the development of analytical devices, such as biosensors and biochips. [27][28][29][30] In this work, the C. reinhardtii D1 primary structure was used as a template to design new peptides enabling atrazine binding. By computational modeling and automated protein synthesis, the D1 plastoquinone-atrazine binding niche in native and mutated forms was reconstituted and the structural and functional features were analyzed in detail by circular dichroism, fluorescence spectroscopy and microcalorimetry.…”

Section: Introductionmentioning

confidence: 99%

Design and biophysical characterization of atrazine-sensing peptides mimicking the Chlamydomonas reinhardtii plastoquinone binding niche

Scognamiglio

Stano

Polticelli

et al. 2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The plastoquinone (Q(B)) binding niche of the Photosystem II (PSII) D1 protein is the subject of intense research due to its capability to bind also anthropogenic pollutants. In this work, the Chlamydomonas reinhardtii D1 primary structure was used as a template to computationally design novel peptides enabling the binding of the herbicide atrazine. Three biomimetic molecules, containing the Q(B)-binding site in a loop shaped by two α-helices, were reconstituted by automated protein synthesis, and their structural and functional features deeply analysed by biophysical techniques. Standing out among the others, the biomimetic mutant peptide, D1pepMut, showed high ability to mimic the D1 protein in binding both Q(B) and atrazine. Circular dichroism spectra suggested a typical properly-folded α-helical structure, while isothermal titration calorimetry (ITC) provided a complete thermodynamic characterization of the molecular interaction. Atrazine binds to the D1pepMut with a high affinity (Kd = 2.84 μM), and a favourable enthalpic contribution (ΔH = -11.9 kcal mol(-1)) driving the interaction. Fluorescence spectroscopy assays, in parallel to ITC data, provided hyperbolic titration curves indicating the occurrence of a single atrazine binding site. The binding resulted in structural stabilisation of the D1pepMut molecule, as suggested by atrazine-induced cooperative profiles for the fold-unfold transition. The interaction dynamics and the structural stability of the peptides in response to the ligand were particularly considered as mandatory parameters for biosensor/biochip development. These studies paved the way to the set-up of an array of synthetic mutant peptides with a wide range of affinity towards different classes of target analytes, for the development of optical nanosensing platforms for herbicide detection.

show abstract

Nature as a Model for Mimicking and Inspiration of New Technologies

Cited by 30 publications

References 32 publications

Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating

Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating

Plant Complexity and Cosmetic Innovation

Design and biophysical characterization of atrazine-sensing peptides mimicking the Chlamydomonas reinhardtii plastoquinone binding niche

Contact Info

Product

Resources

About