Nanotechnology

1. NANOTECHNOLOGY
DR. NISHTHA WADHWA
DEPARTMENT OF BIOCHEMISTRY
ST. JOHN’S MEDICAL COLLEGE

2. LEARNING OBJECTIVES
 Origins
 Definitions
 Approaches in fabrication
 Nanocarriers
 Applications in medicine
 Nanotoxicity
 Future of nanotechnology

3. ORIGINS
 Term Nano : “nanos” =Dwarf
(Greek)
 1959: The idea behind
nanotechnology: Manipulating
atoms to build things- Richard
Feynman
 1974: Term nanotechnology
coined by Norio Taniguchi.
 1981: Gerd Binnig & Heinrich
Rohrer invented Scanning
Tunneling Microscope to see and
manipulate atoms. (Nobel prize
1986)
 1980s: Popularized by Eric Drexler.

4. DEFINITIONS
 National Nanotechnology Initiative definition:
: “ The manipulation of matter with at-least
one dimension sized between 1 to 100
nanometres.”
 Nanobiotechnology: Incorporation of
biotechnology on the nano-scale.
 Nanomedicine can be defined as the science
and technology of monitoring, repairing,
constructing and controlling human biological
systems at the molecular level, in order to
preserve and improve human health.
 Nanomolecular diagnostics: the use of
nanobiotechnology in molecular diagnostics

5. How much is exactly one
nanometer?
 1nm= 10-9 meters
“ Fingernails grow a
nanometer every second”
 Its about 3-5 atoms wide.

6. APPROACHES
1. Top Down
 uses nanofabrication tools, starting
from larger dimensions, to create
nanoscaled structures or devices of the
desired shape and order.
2. Bottom up
 involves the use of molecular self–
assembly/ self-organisation to achieve
functional systems from the controlled
deposition of atoms or molecules

7. NANOCARRIERS
 A nanocarrier is nanomaterial being used as a transport module for
another substance, such as a drug.
 Can specifically target the site of disease
 Targeted drug delivery: Reduction in the drug dose and its harmful
effects on healthy tissues.
 Imaging: enhance the image contrast, by real-time bio-distribution.
 Simultaneous strategic drug and gene delivery.
 Can be multifunctional.

8. Classification
Nanocarriers
Organic-based Inorganic-based Hybrid
• Dendrimers
• Micelles
• Liposomes
• Carbon-bases
• Metallic nanoparticles
• Silica nanoparticles
• Quantum dots
multi-functional carrier
system.

9. Size and shape diversity of nanocarrier-based systems:
 Spherical, ellipsoid, cylindrical etc; 1 to 100nm
 100 to 10 times smaller than human cells: Can readily interact with
biomolecules on the surface and inside the cells.

10. Surface coating
 Polyethylene glycol ( PEGylation).
 Outcome:
 increase of time they stay in the
blood circulation, as carriers are not
easily taken up by the macrophages.
 good solubility in aqueous solutions
 flexibility of its polymer chain
 low toxicity and immunogenicity.

11. 1. Liposomes:
 spherical vesicles
 30 nm to several micrometers.
 lipid bilayers located outside the
aqueous units with polar groups
headed both towards the exterior
and interior aqueous phases.
 Liposomes might encase both
hydrophobic and hydrophilic
substances, prevent the
of their contents and release them
for a set purpose.

12. 2. Dendrimers
 branched, tridimensional polymers that
resemble a sphere.
 1-10nm
 Their internal structure consists of a
multifunctional core and branches of
dendrimers called dendrons that fan out
the core.
 Dendrons are capped with free functional
groups that might be swapped for other
substituents in order to modify the chemical
and physical properties of the whole
 Various pharmacologically active molecules
can be encased within the interior cavities of
dendrimers or connected to their surface
groups

13. 3. Micelles
 polymeric structures,
 below 50 nm
 dispersed in a liquid colloid.
 hydrophilic head, surrounded by
and a hydrophobic tail in their core.
 The drug is encapsulated into he core
cavity formed by the hydrophobic tail.
 The hydrophilic head provides a long
circulation time .

14. 4. Nanotubes and fullerenes
 Good electric, thermal and optical
properties.
 Carbon nanotubes: cylindrical carrier
‘vehicles’
 can be functionalized to act as a drug
delivery system.
 Nanotubes can be loaded to the
tumor site and then excited with radio
waves, resulting in the heating up of
the abnormal cells that would kill
 Fullerenes form a sphere or an
ellipsoid, inside which drug molecules
can be incorporated.
 advantage of therapies based on
fullerenes is that fullerenes are
expected to carry multiple drug loads.

15. 5. Quantum dots (QDs)
 semiconductor nanocrystals, about 2–
10nm.
 Importance: : in vivo imaging-
real-time biodistribution and target
accumulation of drug.
 By the illumination effect of ultraviolet
light, QDs are used to localize cells or
their activities (different sizes of the
QDs give corresponding wavelengths).
 advantages of QDs compared to
fluorescent molecules: intensity of the
signal is brighter and present better
photostability as well.

16. 6. Gold nanoparticles
 Considered very powerful labels for sensors because of the variety of
analytical techniques that can be applied to detect them.
 Size:10–20 nm in diameter.
 Small pieces of DNA can be attached to gold particles and the
nanoparticles assemble onto a sensor surface in the presence of a
complementary target.
 By this technique, a number of different DNA sequences can be detected
simultaneously, using multiple DNA strands in the surface.

17. 7. Magnetic nanoparticles
 iron nanoparticles
 size ranges from 15 to 20 nm.
 These nanoparticles are used for in vivo diagnosis as labelling
molecules for bioscreening.
 The use of magnetic nanoparticles is usually combined with MRI for
vivo imaging.

18. APPLICATIONS

19. Nanomedicine in Regenerative Medicine
 New scaffolds and grafts.
 Their revolutionary design allows for a greater regenerative
effect .
 Carbon nanotubes (CNTs) have been used for repairing
damaged tissues, especially those that require electrical
stimuli.
 CNTs can transport proteins through the cell membrane in
order to induce their naturally mediated effect.

20. Nanomedicine in the Early Diagnosis of
Diseases: Nanomolecular diagnostics
 Faster and more sensitive
because of the
nanoparticles, which are
used as labels for in vivo or
in vitro imaging.

21. In-vitro diagnostics
 Includes: Nano biosensors, nanoarrays, biochips of different
elements (DNA, proteins, and cells) and lab on-a-chip devices
 Main advantages:
 Only small amounts of the sample are needed
 Smaller, easier to use and cheaper than the conventional ones.

22. 1. Nano biosensors
 conjugated with biological molecules such as DNA, proteins, tissue, cells,
biomimetic molecules like aptamers and macrophage inflammatory
 Interaction between the recognition elements and molecules of the sample
causes changes in one or more physical-chemical properties (ion transfer,
pH, heat, and optical properties).
 These physical-chemical changes produce an electronic signal, which
evaluates the presence of the analyte of interest and its concentration in
sample.

23. Cantilever biosensors’ technology
 based on transformation of a reaction into a mechanical motion on the
nanometer scale, which can be measured directly by deflecting a light
beam from the cantilever surface.
 Provide fast, label-free recognition of specific DNA sequences for single-
nucleotide polymorphisms, oncogenes, and genotyping.
 Also, cantilever biosensors provide real-time measurements and
continuous monitoring of clinical parameters in personalised medicine.

24. Viral Nanobiosensors
 viruses can be considered as biological nanoparticles.
 Herpes simplex virus, Hendra virus and adenovirus are used to promote
the assembly of magnetic nanobeads as nanosensors for clinically
viruses.
 These nanosensors can detect as few as five viral particles in a 10 ml
sample.
 Also viruses can be used as sensors that utilize piezo-electric methods
include mass based biosensors, which are essentially based on atomic
force microscopy (AFM).
 It is feasible to apply such electromechanical devices for virus detection,
owing to the relatively high macromolecular mass of these entities.
 Contrary to molecular diagnostic techniques like ELISA and PCR, this
diagnostic method is more sensitive, more efficient, cheaper, faster and
with fewer artefacts.

25. Optical Nanobiosensors:
 The most widely used optical biosensors are those that use the Surface
Plasmon Resonance (SPR) technology.
 Optical-detectable tags can be formed by Surface Enhanced Raman Scattering
(SERS) of active molecules at the glass-metal interface.
 Various small molecules are used for different types of tags.
 SERSbands are 1/50 the width of fluorescent bands.
 the spectral intensity of SERS-based tags is linearly proportional to the number
of particles. Consequently, it achieves a greater degree of multiplexing,
allowing these tags to be used for multiplexed analyte quantification than
current fluorescence-based quantification tags.
 SERS-based tags are stable, resistant to photodegradation and are coated with
glass so that biomolecules such as proteins can be easily attached on the tags.
 The particles can be interrogated in the near-infrared range, enabling
detection in blood and other tissues.
 A single test without interference from biological matrices, such as whole
blood, can be measured up to 20 biomarkers and it is available by Nanoplex
Biotags (Oxonica).

26. 2. Nanoarrays
 important tools for early detection of diseases.
 have been widely applied in the study of various
conditions, including atherosclerosis, breast cancer
, colon cancer and pulmonary fibrosis.
 These novel nanoarrays are divided into three
categories:
 (i) label-free nucleic acids analysis using
nanoarrays,
 (ii) nanoarrays for protein detection by
conventional optical fluorescence microscopy, as
well as by novel label-free methods such as atomic
force microscopy, and
 (iii) nanoarray for enzymatic-based assay.
 With further miniaturisation, higher sensitivity, and
simplified sample preparation, nanoarrays could
potentially be employed for biomolecular analysis
in personal healthcare and monitoring of trace
pathogens
Detection of HIV-1 p24 antigen using
a nanoarray of anti-p24 antibody

27. 3.Lab-on-a-chip:
 The term lab-on-a-chip refers to a single
device which integrates one or several
laboratory functions on a single chip.
 These functions include sample
purification, storage, mixing, and detection.
 These chips use pressure, electroosmosis,
electrophoresis and other mechanisms to
move samples and reagents through
microscopic channels and capillaries
 advantages are the extremely rapid analysis
of small samples, the high degree of
automation and the low cost due to the low
consumption of reagents and samples.
 Some of the applications of lab-on-a-chip
are in realtime polymerase chain reaction
and immunoassays to detect bacteria,
and cancers. It can also be used in blood
sample preparation to crack cells and extract
their DNA.

28. In vivo Diagnostics
 The most popular nanoparticles that are used for in vivo
diagnostics are gold nanoparticles, quantumdots (QDs), and
magnetic nanoparticles due to their size and unique optical
properties.
 For instance, their size ranges from 20 to 200 nm, so they
can avoid renal filtration, leading to prolonged residence
time in the blood stream

29. Targeted Drug Delivery
 The concept of drug targeting to the
desired cell or tissue aims to achieve the
maximum therapeutic effect with the
minimum risk-to- benefit ratio.
 Nanocarriers, are engineered to
 (i) freely traverse through the body and
penetrate tissues (i.e., tumours)
 (ii) be taken up by cells via endocytosis, and
 (iii) recognize specific biophysical
characteristics and thus reach the target-
cells, while minimising drug loss and toxicity
to the non-desired sites.

30. ideal characteristics of a nanocarrier
Characteristic Comments
Decreased
toxicity
use of biodegradable/biocompatible materials
which are metabolised into non-toxic components
Size
(10–200 nm)
large enough to avoid leakage into capillaries (20–200 nm),
but not so large (>200) to be susceptible to macrophage –
based clearance.
Stability should provide stability to the encapsulated drug, (i.e., be
stable to the physiological environment of the body such as
pH values, ionic strength, temperature etc.).
Clearance
mechanism
Small particles (0–30 nm)- rapidly cleared by renal excretion;
Nanocarriers >30 nm are cleared by the mononuclear
phagocytic system
Long circulation
times
in order to find and
sequester in the desired cells.
Ability to target the
desired
cell/tissue
capable of surface bioconjugation
to have the ability to recognise specific biophysical
characteristics to target molecules within the body

31. multifunctional nanocarriers
 the combination of various drugs,
targeting different biological
targets
 as well as the combination of a
drug and an imaging agent in
one nanocarrier, represent only
some of the future challenges.

32. Clinical Applications for Nanocarrier-
Based Drug Delivery

33. Cancer:
 Chemotherapeutic agents are poor in tumor specificity and,
therefore, exhibit dose-limiting toxicity.
 Advantage of Nanocarrier-based drug delivery systems: ability
to target directly the cancer cell, release the drug in a
controlled rate and maximize the therapeutic efficacy,
enhance the delivery of chemotherapeutics across the blood
brain barrier (BBB).
 Passive target for nanocarriers: unique pathophysiologic
characteristics of tumors (i.e., high vascular permeability or
extensive angiogenesis).
 Candidate carriers : Gold nano particles, functionalised
liposomes, albumin-based-particles, dendrimers and
polymeric micelles

36.  FDA approved:
 PEGylated liposomal formulations of doxorubicin
found to extend the half-life of the drug substantially
 albumin-based paclitaxel nanoformulation, Abraxane,
efficiently targets tumour cells.

37. Infectious diseases:
 Nanoformulated drugs are being designed to specifically
deliver therapeutics to sites of infection and in regions of the
body that are often difficult to reach
 Candidate carriers : Polymeric liposomes, dendrimers and
micelles
 liposomes may also be used in order to enhance the
absorption through the mucosal tissues, thus facilitating, the
delivery of the antigens to the mucosal surfaces of the body

38. Metabolic and Autoimmune diseases:
 Metabolic and autoimmune diseases (i.e., diabetes and
osteoporosis) are generally treated with chronic and frequent
drug injections.
 Thus, nanocarrier-mediated drug delivery system should
provide a controlled and sustained delivery of the drug to
achieve the optimum therapeutic effect with the minimum
number of doses.
 A controlled drug biodistribution to provide greater targeting
to the inflammatory cells is also needed.
 Polymeric nanoparticles and liposomes are the most effective
candidates.

39.  Central nervous system diseases (CNS):
 In the case of the CNS diseases, the delivery methods used so
far do not provide adequate delivery and distribution of the
drugs across the blood brain barrier.
 Nanoparticles have the potential to overcome the barriers and
effectively transport to the CNS.
 PEG-modified liposomes, as well as liposomes combined with
viral components (virosomes), have also been employed to
target specific sites in the brain.

40. Drug Targeting Approaches
 E.g. Liposomes, polymeric nanoparticles
and micelles
conjugation of active agents (targeting ligands) to the
nanocarriers

41. Other applications
Nano
technology
Nano
robots
Nano
knife
Biomarker
harvesting
Nano
dentistry
Respirocytes - "Artificial Mechanical
Red Cell"
Clottocytes - "Artificial Mechanical
Platelets"
Microbivores - "Artificial Mechanical
Phagocytes"
it is feasible to tailor nanoparticle
surfaces to selectively bind a subset
of biomarkers and sequester them
for later study

42. Nanotoxicology and Safety Aspects

43.  Nanotoxicology aims to study the adverse effects of
engineered nanomaterials on living organisms and
ecosystems, in order to prevent and eliminate adverse
responses and also evaluate the risk-to-benefit ratio of using
nanoparticles in medical settings.
The toxicity of nanomaterials were broadly classified into two :-
 BIOLOGICAL TOXICITY
 ENVIRONMENTAL TOXICITY

44. Biological
Toxicity:

45. Environmental Toxicity
 Nanoparticle pollution, by deposition of nanoparticle in
groundwater & soil.
 Process that control transport & removal of nanoparticles in
water and waste water are yet to be investigated.
 Studies on the effect of nanoparticles on plants and microbes
are also rare.

46. REASONS FOR TOXICITY :-
 Surface area to volume ratio of the particles which increases their
interaction with the surrounding molecules.
 Chemical composition of the particle which is responsible for its
reactivity.
 Surface charge of the particle is responsible for electrostatic
interactions.
 Complementarity of nanostructure could cause inhibition of enzyme
activity either competitive or non competitive.

47. FUTURE

48.  Mobile nanorobots, equipped with wireless
transmitters, could circulate in the blood and lymph
systems, and send out warnings when chemical
imbalances occur or worsen.
 Similar fixed nanomachines could be planted in the
nervous system to monitor pulse, brain-wave
activity, and other functions.
 Implanted nanotechnology devices could dispense
drugs or hormones as needed in people with chronic
imbalance or deficiency states.
 In heart defibrillators and pacemakers, nanomachines
could affect the behavior of individual cells.
 Artificial antibodies, artificial white and red blood
cells, and antiviral nanorobots might be devised.
 The most advanced nanomedicine involves the use of
nanorobots as miniature surgeons. Such machines
might repair damaged cells, or get inside cells and
replace or assist damaged intracellular structures. At
the extreme, nanomachines might replicate
themselves, or correct genetic deficiencies by altering
or replacing DNA (deoxyribonucleic acid) molecules.

49. Summary

50. References
 Varvara Karagkiozaki Stergios Logothetidis, Horizons in Clinical
Nanomedicine
 Kewal K. Jain: Applications of Nanobiotechnology in Clinical Diagnostics.
Clinical Chemistry 53:11 DOI:
10.1373/clinchem.2007.090795
 Zygmunt Zdrojewicz, Mateusz Waracki, Bartosz Bugaj, Damian Pypno,
Krzysztof Cabała. Medical applications of nanotechnology. Postepy Hig
Med Dosw (online), 2015; 69: 1196-1204
Thank you