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4 Smart Nanomaterials for Sensor Application Singh et al.
properties could be varied in a controlled manner under the influence of external stimuli such as
temperature, force, moisture, electric charge, magnetic fields and pH. The piezoelectric materials produce
voltage under stress or alter the shape under the influence of electric charge. Thermoresponsive materials,
sometimes also known as shape memory alloys or shape memory polymers, alter their shape under the
influence of the ambient temperature. Like thermoresponsive materials, magnetic shape memory alloys
change shape due to changes in magnetic fields. Polychromic, chromogenic and halochromic materials
change their color due to external influences like pH, temperature, light or electricity. Materials that change
colour due to temperature are normally known as thermochromic materials and those that of light are a
photo chromic materials. Applications of smart nanomaterials have made their presence strongly felt in
various areas like healthcare, implants and prostheses; smart textiles, energy generation and conservation
with energy generating materials and highly efficient batteries, defence, security, terrorism, and
surveillance using smart dust and smart dust motes (nano-sized machines used in a range of sensors and
wireless communication devices) due to their wherewithal of amplifying the signals employing biomarkers
[3]. Fig. 1 shows the various kinds of nanomaterials which may be used to amplify biomarker signals.
Figure 1. Various kinds of nanomaterials utilized for the amplification of biomarker signals.
Bionanomaterial’s research has emerged as a new exciting field and the importance of DNA, RNA and peptides
in designing the bionanomaterials for the fundamental development in biotechnology and nanomaterials have
begun to be recognized as a new interdisciplinary frontier in the field of life science and material science. Great
advances in nanobiochip materials, nanoscale biomimetic materials, nanomotors, nanocomposite materials,
interface biomaterials, nanobiosensors and nano-drug-delivery systems have the enormous prospect in
industrial, defense, and clinical medicine applications. Biomolecules assumes the very important role in
Nanoscience and Nanotechnology, for example, Peptide Nucleic Acids (PNAs) replace DNA, and act as a
biomolecular tool/probe in the molecular genetics diagnostics, cytogenetics, and also have enormous potentials
in pharmaceutics for the development of sensors/arrays/chips besides many more applications. One of the
current aspects related with PNA is the making of a new hot device for the commercial application, e.g.
nanobiosensor arrays [4]. The integration of nanotechnology, micro fabrication techniques, and miniaturized
devices with novel biochemical detection methodologies, leads to very sensitive and fast assays for the
detection of desired biomolecules related with various commercial sectors. Nanotechnology involves the
assembly of small molecules into complex architectures for improvised function by controlling the precise
location of each atom in a 3-dimensional space. It forms larger functional elements and is being explored as the
potential tool to fabricate nanometer size devices. [5, 6] Numerous reports are documented regarding the use of
oligonucleotides for building nanostructures, which include DNA matrices based on subunits of fixed Holliday
junctions, streptavidin-DNA fragment nanoparticle networks, DNA dendrimer formations for drug delivery,
molecular tweezers (ssDNA based) and molecular switches. [7, 8] PNAs are promising connectors for the
assembly of DNA based nanostructures with an exceptional ability to hybridize the sequences within the duplex