This presentation gives detailed description of Green Nanotechnology including its principles & significance. Illustrated with examples for its application in various biomedical research fields.

1. Green Nanotechnology
&
Its Application
in Biomedical Research
-- By Runjhun Dutta

2. WHY GREEN SYNTHESIS?
 It removes the complicated protocol.
 It can also meet the large-scale production requirement.
 Methods using lower and higher plant materials and their products; fungi and sometimes
microorganisms for NPs fabrication are ecofriendly.
 Since these materials are easily available and do not require organic solvent as reaction medium, they
are easy to handle and economical.
 In major cases the NMs thus synthesized are capped by biomolecules like phenols, tannin, flavonoids
and ascorbate present in the plant materials.
 They enhance stability of NPs and also prevent their interaction with atmospheric oxygen. These NMs
are thus not oxidized and can be kept for long period of time without undergoing any change in their
properties.
 Green synthetic methods make use of many waste materials like banana peels, lemon rind, dried leaves
of medicinal plants and algae etc. The precursor even in crude form may react with these materials to
produce NPs.

5. Benefits of bio-derived
fabrication/green
synthesis of nanoparticles
over chemical and
physical procedures

6. Nanoparticles synthesis via biological and physicochemical approaches

7. 1
2
3
Protocols for nanoparticle synthesis
a) Bottom-up approach for the synthesis of nanoparticles via self-
assembling of various nuclei
b) Top-down approach for the synthesis of nanoparticles via size
reduction

8. Nanoparticles synthesis by flowers and leaves
of plants (Wang et al. 2019)
 Parts of plants are thoroughly washed with
the help of tap water and sterilized by
double-distilled water followed by drying at
room temperature.
 The dried sample goes to the process of
weighing and crushing.
 Afterward, plants extract is mixed with
Milli-Q water as per desired concentration
and boiled with continuous stirring.
 The obtained solution is then filtered with
Whatman filter paper, and the part in which
there is a clear solution was useful for
sample (plant extract).

9. Detailed scheme of bio-derived
fabrication/green synthesis of
nanoparticles using lower/higher plant
materials and their products; fungus and
microorganisms

10. Flowchart for synthetic route, characterization and applications of green synthesis of palladium and
platinum nanoparticles from plant’s extract. [Siddiqi and Husen (2016)]

11. Green synthesis of silver nanoparticles by plants extract and AgNO3, its characterization and applicants in
various biomedical fields.

12. Synthetic route of gold nanoparticles by bio-reduction and stabilization of chemical moieties
present in the biogenic complexes.

13. Synthesis of palladium nanoparticles using Catharanthus roseus methanolic leaf extract and
palladium ion

14. Synthesis of Pd
nanoparticles by black
tea leaves (Camellia
sinensis) extract, its
catalytic activity in
Suzuki coupling reaction,
and reduction of 4-
nitrophenol.

15. Biosynthesis of zinc oxide (ZnO) nanoparticles using plants, microorganisms, and others

16. Biosynthesis of Cu
nanoparticles by using
Cuscuta reflexa leaf extract

17. Mechanism for the formation of CuONPs
Authors have argued that the precursor CuSO4
reacts with hydroxyl anion OH-, generated by the
ionization of water molecules and eventually
reduced by phytochemicals present in the seed
extract.
It must be clarified at this stage that:
(a) It is universally known that water is not
ionized until acidified water is electrolyzed.
(b) Cu (OH)2 can be formed only if NaOH or
requisite amount of NH4OH is added to a
copper salt as shown adjacent.

18. However, CuSO4 remains ionized in aqueous
medium or it may form hexaaquo copper
complex, [Cu(H2O)6].
Free Cu2+ ion is then reduced by protein or
polyphenol available in the black bean
extract.

20. Applications of green synthesized nanoparticles in environmental and
biomedical fields

21. Applications of palladium and platinum nanoparticles in chemistry, biology, and
material science fields

22. Recent studies (during 2018–19) on plant-mediated synthesis of Cu-NPs, their morphology, and various applications

24. Sustainable synthesis of cobalt and cobalt oxide nanoparticles and their catalytic and
biomedical applications

25. Silk Biomedical Applications
Tissue Engineering
Drug Delivery Systems
Biomedical Implants
Diagnostic Medical Devices
Silk Intrinsic Properties
Biocompatibility
Controllable Biodegradability
Excellent Mechanical Properties

26. Two approaches used to functionalize silk with
nanomaterials:
(1) Post-functionalization methods
(2) Feeding silkworms with modified diets containing
nanomaterials.

27. Feeding silkworm with Nanomaterials: A Greener Approach
 In recent years, several attempts have been made to produce silk fibers with improved properties and new
functionalities by feeding silkworms with modified diets containing nanomaterials.
 Nanomaterials possess unique physical, chemical, and biological properties and when combined with silk
can expand its applicability for biomedical applications.
 Feeding silkworms with modified diets containing nanomaterials is a greener method of producing
functionalized silk fibers when compared to the alternative post-functionalization methods that include
multistep procedures and toxic chemicals.
 The main advantages of using this greener method are related to the reduced usage of resources such as
water, energy, and additional chemicals to spin functional silk fibers, the maintenance of intrinsic silk
properties, the stability of the added new functionalities, and the possibility of large-scale production.
 Feeding silkworms with different nanomaterials such as carbon-based nanomaterials, metal and metal oxide
nanoparticles, and quantum dots has led to the production of silk fibers with improved properties (e.g.,
mechanical and thermal) and/or new functionalities (e.g., magnetical and luminescence).
 However, nanomaterials concentration, dimensions, and solubility were shown to influence their uptake by
silkworms as well as silk fiber properties.

28. Feeding silkworms with modified diets containing nanomaterials, a green strategy to produce multifunctional
SFs:
(A) Silkworms are fed with nanomaterials sprayed in mulberry leaf or mixed in mulberry powder diet.
(B) Ingested nanomaterials (e.g., carbon nanotubes, nanoparticles, quantum dots) are mixed in the silk
glands of the larvae and incorporated in the SFs, which acquire improved properties and new
functionalities

29. Bacterial synthesized metal and metal salt nanoparticles in
biomedical applications
 The green route synthesis exploits diverse reducing and stabilizing agents from
bacterial resources for the successful synthesis of metal nanoparticles.
 Bacteria have the unique potential of intra- or extracellular production of inorganic
materials. Bacteria also produce nanoscale dimension of secondary product with
varied morphology. Due to the unique and versatile characteristics of microbial
resistance to most toxic heavy metals, there are great advantages associated with the
production of several metal nanoparticles.
 From cell biology study reveals that, the resistance is mainly due to the chemical
detoxification and energy-dependent ion efflux of the cell by functional membrane
proteins as either ATPase or chemiosmoticcations or proton anti-transporters.
 The bacterial mediated synthesis of nanoparticles has more importance in
commercial application due its extracellular conversion of soluble toxic inorganic
ions to nontoxic nano-clusters.

30. Possible mechanism involve in the synthesis of nanoparticles by bacterial reductase enzymes and extracellular
proteins

31. Bacterial exopolysachharide [EPS] mediated synthesis of nanoparticles

32. Possible mechanism on active role of electron shuttle quinones [redox mediators] in the synthesis of metal nanoparticles

33. Schematic illustration of mechanistic aspects for antibacterial influences of the produced NPs.
bacterial influences of the produced NPs.

37.  Cobalt oxide NPs synthesized using polymorphic bacterial templates.
 Electron microscopic images and the prepared nanostructured materials.
 The bacterial templates could be efficiently eliminated by calcination while retaining the original shape and size.

40. (a) Production of lignin NPs and lignin NPs/PVA composite film.
[ZP: Zeta-potential value, PDI: polydispersity index]

41. (b) Suggested mechanism for UV-shielding and antioxidant activity by applying lignin NPs as the functional additive.

42. Beneficial effects of lignins and their derivatives.

44. Synthesis of nanomaterials
via plants, bacteria & wood
Principle of green synthesis
Advantages of green
synthesis over conventional
methods
SUMMARY
Biomedical Applications of
nanomaterials generated
through green
nanotechnology

45. Let’s join hand for a green future.
The need of today is to foster development but not at the cost of mankind.
Thus, there is an urgent need to promote green nanotechnology for human and
environmental sustainability. The development and commercialization of
viable green nanotechnologies is difficult and require concerted effort from the
researchers, government and other stakeholders. The development of this
environmentally friendly technology can go a long way in accelerating human
welfare.

46. Thanks!