Page 16 - 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

Molecular motors are molecular devices, typically imple‑ tible. Additionally, their interaction with
mented with rotaxane‑ or catenane‑type mechanically‑ external stimuli, such as light, magnetic and electric
ields, tend to be much stronger, which makes them
interlocked molecular architectures, that can perform
attractive for externally controlled applications
work that in turn in luences the system as a function
[32]. Janus nanomachines, which are made of Janus
of trajectory with chemical, light or electrochemical Nanoparticles (JNPs), nanostructures with two
energy inputs [34, 35]. Molecular motors are chemically distinct parts, are the most popular
promising for biomimicking applications such as inorganic nanomachines due to their anisotropic
structures that give rise to exceptional propulsion
synthesizing new molecules from individual atoms
capabilities [39]. This anisotropy results in a chemical
and molecules in a programmable manner, just as
potential or thermal gradient in JNPs upon
their biological counterparts, such as ribosome. On the chemical catalysis or external light irradiation,
other hand, molecular switches reversibly change the which in turn, leads to the phoretic low of
state of the system upon the application of surrounding luid around the entire JNP surface. As a
result of this phoretic low, JNPs actively move in the
stimuli by producing no net work. Molecular
opposite direction. There are also proposed
switches are being utilized for high‑resolution
architectures of self‑propelled Janus nanomotors wor‑
molecular sensing applications and promising for king based on the decomposition of hydrogen
future molecular computer architectures capable of peroxide into oxygen as a driving force. Moreover,
both digital and analog computing [32]. the use of mesoporous silica nanoparticles (MSNs)
as JNPs has opened up new biomedical opportunities
Self‑assembled nanomachines are nanoscale devices that which involve the targeted delivery and contro-
lled release of therapeutic and diagnostic agents
are built based on autonomous or programmed organi‑
encapsulated in their porous structure [40]. Although
zation of constituent molecules, and can perform similar much has been done to devise exquisite and
functions to molecular machines, such as switching, logic complex molecular and nanomachine architectures
gating, active propulsion, typically at larger length scales that can perform sensing, cargo transport, and
[32]. Self‑assembled DNA nanomachines have particu‑ switching operations, the potential of intercon-
necting these tiny machines for a wider range of
larly attracted research interest due to the high‑level con‑
biomedical applications has only recently
trol of their assembly through DNA origami techniques,
attracted signi icant attention. Seveeral commu-
which enable the selective folding of DNA strands into nication modalities have already been
particular designs with the use of short staple strands [36, considered to enable controlled interaction
37]. Selective targeting and versatile functionalization and coordination of these devices, such as
diffusion‑mediated communication, which is based on
of DNA nanomachines have expanded their application
the exchange of small molecules, e.g., glucose, through
areas, which involve bio‑inspired dynamic DNA walkers,
the signaling cascades triggering enzymatic reactions
cargo‑carrying DNA boxes with stimuli‑responsive logic that fuel the movement of the receiver devices, and cell
gate‑based opening mechanisms, and stimuli‑responsive or cell‑free genetic circuits that trigger the
DNA switches [38]. expression of a certain kind of protein, e.g.,
green luorescent protein (GFP), in the receiver
BNTs [41, 42, 43, 44]. External energy‑
Alzheimer & Epilepsy Monitoring
and Brain Stimulation mediated communications have also been widely
Nanonetworks
studied to enable the small networks of
molecular and nanomachines. This form of interac‑
Interconnected tion occurs through several biophysical phenomena,
Body-Area Nanosensor
Networks such as pore formation and modulation of enzyme
cascade re‑ actions, which are triggered by external
Heart stimuli such as light, chemicals, temperature, and
Monitoring
INTERNET Networks electric and magnetic ields, and provides higher level
Cancer of spatiotemporal control compared to the
Monitoring/
Drug Delivery diffusion‑mediated communication [41]. Non‑covalent
Networks interactions considered for molecular and nano-
machines involve the short‑range electrostatic and
Health-care Bio-cyber hydrophobic/hydrophilic interactions, as well as
provider interface complex formation through reversible ligand‑receptor
binding interactions. Lastly, inducing dynamic collective
Fig. 1 – Conceptual drawing of a continuous health monitoring applica‑
behaviors of active nanomachines, such as Janus
tion of IoBNT.
nanomachines, through external stimuli, e.g., light,
Hybrid inorganic nanomachines are sub‑100‑nanometer electric and magnetic ields, has also attracted great
attention due to their emergent out‑of‑equilibrium
devices that of metal, metal o or
properties resembling natural systems [45, 46, 47].
hybrid (NPs) [32 comparison to
Incorporation of these interacting molecular and
self‑assembled molecular machines, nanomachines into the larger IoBNT framework as
biomolecular tend heterogeneous BNTs can enable unpre-
more structurally rigid, however biocompa- cedented therapeutic and diagnostic applications via

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