Page 15 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 3 – Internet of Bio-Nano Things for health applications

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 3

transfers information about external stimuli to the brain, and micro organisms in soil. Although there is no physical
which is a dense network of highly complex neuron cells. nervous system in plants, electrical communications have
The brain processes all this information and sends been observed between the roots and the body of plants
back commands to the body accordingly to control the [26], and capillary networks carry molecular information
vital functions, behavior and physical activities. Other to the various parts of the plant along with water and nu‑
networks spanning the whole body yet carrying trients. Furthermore, nearby plants use pheromone com‑
information on a slower scale than the electrochemical munication to coordinate their behavior to avoid over‑
pulses of nervous nanonetworks, are cardiovascular growth and shadowing each other and to warn each other
system and the endocrine system both composed of against attacks from animals and bugs [27, 28]. Con‑
vessels carrying information in molecular form in blood sidering the many species of plants in a forest, various
and lymph, respectively [4]. weed and grass on top of the soil, ivies and the trees on
which they live symbiotically, plant networks enable a
2.1.2 Bacterial nanonetworks high level coordination to share the resources and opti‑
mize growth of each plant. Another element helping this
Besides the IoBNT in multicellular organisms such as hu‑ coordination is the presence of rhizobiome, i.e., the root
man body, single cell organisms such as bacteria show associated microbiome, which are shaped by the plant
coordination and group behavior enabled by intercellu‑ signaling primary and secondary root metabolites [29].
lar signaling. The irst communication mechanism among In turn, the rhizobiome consisting of multiple species
bacteria discovered is quorum sensing (QS), the ability of bacteria helps the roots to reach necessary nutrients
to detect and respond to cell population density repre‑ from the soil and protects the plant against pathogens.
sented by the concentration of the signaling molecules This rhizobiome‑plant interaction signi icantly affects the
called auto‑inducers [19]. QS controls bio ilm forma‑ health and growth of the plant.
tion, virulence factor expression, production of secondary
metabolites and stress adaptation mechanisms. Using Bio‑Nano Things
this mechanism, unicellular bacteria coordinate their be‑
havior and act as if they are a uni ied multicellular orga- In IoBNT framework, Bio‑Nano Things are de ined as ba‑
nism. Recently, besides the molecular means of QS, sic structural and functional units operating at nanoscale
electrical means of communication among bacteria has within the biological environment [1]. BNTs are expected
been shown [20]. The bacterial membrane potentials typical of embedded compu-
creating potassium waves through bacterial bio ilms ting devices IoT sensing, processing,
synchronize the behavior of bacteria in bio ilms. In actuation, and communication.
case of nutrient depletion in the center of the bio ilm, T build electrical
this signaling mechanism warns the outer circle of devices with nanotechnology and encapsulating these de‑
bacteria in the bio ilm to slow down growth vices for biocompatibility However, at such a small size,
allowing more nutrients to penetrate to the center. miniaturized electrical BNTs suffer from lack of space for
Using the above‑mentioned communication mechanisms, provide suf icient antenna
bacteria form spatio temporally organized community generating usable frequencies. Another to
structures optimizing the growth and itness of the whole build BNTs biological substrates
colony which resembles a decentralized decision‑making as cells which can be considered standalone devices
system of millions of interconnected nodes. Studies also that harvest energy from environment.
show that bacterial colonies engage in social behavior Another important of BNTs molecular and
such as competition, collaboration, and cheating during nanomachines, which are tiny arti icial devices with fea‑
the production of public goods [21]. Despite the sizes between 100 that perform a
limited resources of a single bacterium, tight useful task at nanoscale [30, 31 Recent years have ob‑
coordination in the bacterial populations containing this served the design and implementation of molecular and
sheer number of bacteria can be established. Hence, increasing complexity sophisti‑
bacterial nanonetworks provide lots of clues to IoBNT expanding of their applications, which
researchers that are looking to form networks of large molecular factories, self‑propelling cargo
numbers of BNT devices with limited power and carriers, nanosensors, molecular computation [32].
communication resources [22, 23, 24, 25]. coarse‑grained level, molecular nanomachines
can be categorized into three main groups: molecular ma‑
2.1.3 Plant networks chines, self‑assembled hybrid inor‑
ganic nanomachines.
Among the natural IoBNTs, plant networks are the most Molecular machines are synthetic molecular systems con‑
counterintuitive since plants seem to be immobile and sisting of single or a few molecules that can undergo a me‑
solitary. However, the growth and development of plants chanical stimulation use‑
are highly dependent on the communication both within task [33]. This of BNTs further divided
a plant itself, among different plants, and between plants categories: molecular motors switches.

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