Nanoscale science (or nanoscience) researches the phenomena, properties, and responses of materials at atomic, molecular, and macromolecular scales, and in general at sizes between 1 and 100 nm. In this scale, and especially below 5 nm, the properties of matter differ significantly (i.e., quantum-scale effects play a key role) from that at a larger particulate scale (Nguyen et al., 2009). Nanotechnology is then the design, the manipulation, the building, the production and application, by regulating the shape and size, the properties-responses and functionality of structures, and devices and systems of the order or less than 100 nm. Nanotechnology is considered an advancing and emerging technology due to the possibility to advance well-established products and to create new products with totally new characteristics and functions with enormous potential in a wide range of applications (Azzam, 1977).

1. Gecko Inspired Nanomaterials
BY
Dr. SREEREMYA.S
FACULTY OF BIOLOGY

2. • Nanoscale science (or nanoscience) researches the phenomena,
properties, and responses of materials at atomic, molecular, and
macromolecular scales, and in general at sizes between 1 and 100
nm. In this scale, and especially below 5 nm, the properties of
matter differ significantly (i.e., quantum-scale effects play a key
role) from that at a larger particulate scale (Nguyen et al., 2009).
• Nanotechnology is then the design, the manipulation, the building,
the production and application, by regulating the shape and size,
the properties-responses and functionality of structures, and
devices and systems of the order or less than 100 nm.
Nanotechnology is considered an advancing and emerging
technology due to the possibility to advance well-established
products and to create new products with totally new
characteristics and functions with enormous potential in a wide
range of applications (Azzam, 1977).

3. • Applications of nanosciences and nano engineering lie in the fields
of pharmaceutics, cosmetics, processed food, chemical engineering,
high-performance materials, electronics, precision mechanics,
optics, energy production, and environmental sciences
(Stadelmannetal.,2008). Nanoscience especially the emerging
stream called the bio nanotechnology has various aspects to be
understood and there is a huge scope of innovations (Sreeremya,
2017).
• Biomimetics or biomimicry is one of the most excelling fields of the
contemporary world. In layman terms, it means the exchange and
implementation of abstract principles and concepts from living
nature to fulfill our requirements of obtaining better materials and
efficient machinery. From the designing of aircraft by researching
the flight of birds to manufacturing photonic integrated circuits by
studying wing patterns of a butterfly, the field of biomimicry has
always caught man‘s attention (Rasche, 2001).

4. • The solution to some of the most cruesome material fabrication problems and the
design of system models already exist in nature and can be duplicated by looking
more closely at the structures and patterns present in nature. This is what
biomimetics does. It involves the research of how nature works, its models, various
processes by which those models are executed and the different elements
constituting the model (Versteeg et al., 2003).
• Role of Nanotechnology and Nanostructures in Biomimetics
• It was only with the emerging in the field of nanotechnology that we were able to
study the nanostructures present in nature. Most of the wonders of nature take
place at the molecular level, i.e., in the nanoscale, only when powerful analytical
techniques like scanning tunneling microscopy (STM) and atomic force microscopy
(AFM) were developed, were able to look closely at the spectacular working of
natural materials. For example, we were able to mimic gecko feet to fabricate
materials in the lab with the dual characteristics of super hydrophobicity, as well as
high adhesivity towards water, but only after their nanostructured spatulae were
researched. Another famous example is that of a lotus leaf, which has been used
to synthesize self-cleaning, super hydrophobic surfaces.

5. • Now able to synthesize bio inspired materials in the lab by using various
top-down and bottom-up nanomaterial synthesis techniques (Martin,
1997). The top-down approach typically involves consecutive cutting or
slicing of bulk material to obtain smaller and smaller particles until
nanosized particles are obtained(e.g., mechanical ball milling); whereas
the bottom-up approach involves self-assembly of few precursor particles
to obtain the desired nanomaterial (e.g., processes involving chemical
synthesis).Examples prevalent to the field of biomimetics include
fabricating structures mimicking gecko feet by plasma enhanced chemical
vapor deposition , chemical synthesis of artificial antennas—using
bis(phenylethynyl) anthracene (BPEA), borondipyrromethene (BDPY) and
zinc tetraarylporphyrin(ZTAP)—and reaction centers (using porphyrin,
fullerene and carotenoid) for mimicking the process of photosynthesis in
the lab and using the roller nano imprint fabrication technique for
fabricating moth eye-like conical protuberances .

6. • Thus, in a nutshell, the development of sophisticated toolsand techniques to
uncover the secrets of nanostructures and their synthesis methods is what has
ledto tremendous progress in the field of nanotechnology, and this was
responsible for contributing a substantial amount of progress in biomimetics, thus
realizing its full potential(Chang et al.,2004).
• Different Types of Biomimetic-Inspired Nanomaterials and Their Synthesis
Although there are a number of nanomaterials that have been artificially produced
by mimicking the nanostructures present in nature, one will cover here some of
the most important materials with great future application potential. One begin by
observing at the double nanostructured pillars on the surface of a lotus leaf
showing super hydrophobicity and study their design pattern Biomimetics for
artificial synthesis. This is typically followed by the study of nanostructured
spatulae of gecko feet and their dual characteristic of super hydrophobicity and
high water adhesivity.
• In the unloaded conditions, gecko setae are recurved proximally (towards the
animal‘sbody), with the tips bearing the spatularnanoarrays misaligned with the
substrate., the left edge of the figure typically represents the approximate
orientation of a vertical surface relative to an unloaded seta during climbing.)

7. • This small preload and an about 10mmproximaldisplacementof the toe or scansor
may serve to bring the spatulae (previously in a variety of orientations) uniformly
flush with the substrate, pulling the setal shaft in tension. Recently discovered that
adhesion in isolated seta requires a small push perpendicular to the surface,
followed by a small parallel drag. Dragging setae in shear pulls the spatula in
tension hence resulting in large friction and adhesion forces. When properly
oriented, preloaded and dragged, a single seta can generate 200mN in shear and
40mN in adhesion, over three orders of magnitude more than that required to
hold the animal‘s body weight. All 6.6 million setae on the toes of one gecko
attached simultaneously could lift134 kg. Given the surprisingly large attachment
forces generated by their setae, it is remarkable that geckos are able to detach
their feet in just 156ms with no measurable detachment forces. Detachment of
individual setae is accomplished by aggrandizing the angle that the setal shaft
makes with the substrate above 308. This is consistent with models of setae as
cantilever beams and with finite-element modelling of the seta. Elastic energy
storage maybe maximized for shaft angles near 358; however, such a low resting
setal angle may inhibit rough surface compliance.

8. • Optimum detachment of setae occurs when the base is mainly displaced
at an approximate right angle to the setalshaft. High-angle detachment
results in distal elastic unloading of the attached setae causing
spontaneous detachment to occur. It is probable that as the angle of the
setal shaft increases, the spatular forces are typically reduced as the stress
increases causing easy fracture of the spatula–substrate bonds THE GECKO
AND ITS ADHESION CAPABILITIES
• Scientific interest in the gecko began when, more than 2000 years ago, the
Greek philosopher Aristotle first coined the term―, like the Gecko lizard‖.
Since then, this lizard ‘ s amazing ability to climb walls and run on ceilings
has inspired a wealth of researches, many of which have proposed reasons
for the gecko ‘ s amazing adhesive abilities. It was not until the 1960s that
the German anatomist Uwe Hiller made a major breakthrough when,
using electron microscopy, he revealed the bristle - like, hierarchical
structure of the gecko ‘ s toe pads that today, are recognized as being
responsible for the animal ‘ s climbing abilities.

9. REFERNCE
• Journal of Biochemistry and Molecular
Science, Gecko Inspired Nanomaterials, S.
Sreeremya,2018.Vol(1):1,1-8.