Environmental Engineering Reference
In-Depth Information
20
Green SyntheSiS of nanomaterialS USinG
BioloGical roUteS
Rajesh Ramanathan, Ravi Shukla, Suresh K. Bhargava, and Vipul Bansal
NanoBiotechnology Research Laboratory, Centre for Advanced Materials and Industrial Chemistry, School of Applied Sciences,
RMIT University, Melbourne, Australia
20.1
introdUction
In today's modern day science, we can relate future discoveries to one of the most famous and influential talks given by Richard
Feynman “There is plenty of room at the bottom,” wherein the foundation for one of the most important fields known to man-
kind, that is, nanotechnology, was laid [1]. The past few decades have seen the premises of nanotechnology revolutionizing
modern technology with the dawn of several applications including small and flexible devices that can be used for sensing and
electronics to generate a wide array of new generation tools capable of identifying and treating infectious agents [2-8].
To realize the true potential of nanotechnology, it was essential to develop efficient fabrication protocols of nanomaterial
synthesis and testing their potential applications. This saw the introduction of physical methods such as mechanical grinding
toward nanomaterial synthesis, especially in the early years of the field [9]. With gaining importance, solution-based nanomate-
rial synthesis routes were developed (more commonly known as chemical route) that now enjoy a long history and have typi-
cally dominated the nanosphere with well-established protocols for synthesizing particles with excellent control over shape,
size, and properties [9]. With the development of physical and chemical methods, the paramount concern for a negative impact
on the environment was also heightened due to the use of toxic chemicals, reaction conditions involving extremes of tempera-
ture, pressure and pH, as well as the release of harmful by-products. Hence, scientists started investigating alternative strategies
toward new “green” environment friendly fabrication routes for nanomaterial synthesis [9-13].
Unsurprisingly, Mother Nature has developed a large repertoire of functional assemblages of proteins, nucleic acids, and
other macromolecules to perform complicated tasks that are still daunting for us to emulate in our laboratories [9, 10]. One such
task that is an integral part of biological systems is the assimilation of inorganic materials in hard tissues, which are biocom-
posites containing structural biomolecules in addition to some 60 different kinds of minerals that perform a myriad of vital
biological functions [13, 14]. Furthermore, unicellular organisms have also been observed for their ability to synthesize inor-
ganic materials, both intra- and extra-cellularly [15]. Some examples exhibiting bioinorganic materials include magnetotactic
bacteria that synthesize magnetite [16, 17] diatoms that synthesize silica [18, 19] and S-layer bacteria that synthesize gypsum
and calcium carbonate as surface layers [20]. Although it is known that these inorganic materials serve important biological
functions, it was also realized that the study of these minerals from the material science perspective may have significant poten-
tial to transform the fields of physical, biological, and material sciences [9]. The complementary knowledge gained from these
areas of sciences by incorporating the concepts and ideas derived from the biological world to the inorganic material synthesis
has led to a merger between different fields, giving rise to green nanosciences, green nanotechnology and bionanotechnology.
