Nanofibers are defined as fibers with diameters less than 50-500nm. Recently nanofibers are used in the healthcare systems, as a tool for drug delivery system in various diseases. There smaller size plays an important role in delivering the drug to the appropriate site in the body. The objective of drug delivery systems is to deliver a defined amount of drug efficiently, precisely and for a defined period of time. The new technologies and materials will have a profound impact on drug delivery. Either biodegradable or non-biodegradable materials can be used to control whether drug release occurs via diffusion alone or diffusion and scaffold degradation. Additionally, due to the flexibility in material selection a number of drugs can be delivered including: antibiotics, anticancer drugs, proteins, and DNA. Using the various electro spinning techniques a number of different drug loading methods can also be utilized: coatings, embedded drug, and encapsulated drug (coaxial and emulsion electrospinning). These techniques can be used to give finer control over drug release kinetics. Electro Spinning Coaxial electrospinning Multi-jet electrospinning Bubble electrospinning Melt electrospinning This process involves dissolving the drug and polymer in an appropriate solvent. The solution is then placed in a syringe, and a high voltage is applied. A small amount of the polymer solution is drawn out of the syringe, forming a Taylor cone. Increasing the applied voltage further results in the initiation of a charged fluid jet. A stable jet is formed when the charge is increased above a critical voltage, and there is a balance between the surface tension of the fluid and the repulsive nature of the charge distribution on the surface of the fluid.

1. NANOFIBERS
SADANAND UDAY NAGVEKAR
MPH/10037/24

2. INTRODUCTION
• Nanofibers are defined as fibers with diameters less
than 50-500nm.
• Recently nanofibers are used in the healthcare
systems, as a tool for drug delivery system in various
diseases.
• There smaller size plays an important role in
delivering the drug to the appropriate site in the
body.
• The objective of drug delivery systems is to deliver a
defined amount of drug efficiently, precisely and for
a defined period of time.

3. • The new technologies and materials will have a profound impact on drug delivery.
Either biodegradable or non-biodegradable materials can be used to control
whether drug release occurs via diffusion alone or diffusion and scaffold
degradation.
• Additionally, due to the flexibility in material selection a number of drugs can be
delivered including: antibiotics, anticancer drugs, proteins, and DNA.
• Using the various electro spinning techniques a number of different drug loading
methods can also be utilized: coatings, embedded drug, and encapsulated drug
(coaxial and emulsion electrospinning). These techniques can be used to give
finer control over drug release kinetics.

4. Properties of Nanofibers
• Extremely high surface to weight ratio.
• Low density.
• High pore volume.
• Tight pore size.
• Lower crystallinity
• Low Glass transition temperature (Tg)
• Low Melting temperature (Tm)

5. ADVANTAGES
1. Nanofibres can be made using different materials and polymers.
2. Materials could be easily used for electrospinning, with low requirements for
creating fibers.
3. Relatively low startup cost.
4. A high surface-to-volume ratio
Nanofiber have a high surface area-to-volume ratio, greater surface area of
nanofibers permits faster dissolution. The nanofiber with a high surface area to
volume ratio can support cell attachment, proliferation and drug loading.

6. 5. Ease of fiber deposition onto other substrates.
6. Electro spun fibers are frequently deposited on metal, glass, micro-fibrous mat
and water.
7. A variety of nanofibrous structures have been constructed. The creation of
tubular nanofibrous structures, yarns, and three- dimensional blocks of
nanofibers has been made possible by electrospinning setup and modification
in the procedure.
8. Mass production capability: There are also commercially accessible
electrospinning systems for producing nanofibers in large quantities.
9. Commercial applications: Several commercially accessible goods have been
built using the electrospinning technique.

7. DISADVANTAGES
1. The challenges in achieving in-situ deposition of nanofibers on different
substrates.
2. It provides a low yield and needs a high working voltage.
3. Production of nanofibers with these features on a large scale remains complex.

8. TYPES OF NANOFIBRES
Inorganic nanofibers
• The metal nanofibers like Cu, Ni, and Ag are examples of inorganic nanofibers.
Carbon nanofibers
• Carbon nanotubes (CNTs) are structurally more complex systems than CNFs.
• Carbon nanofibers that have been electrospun or vapor-grown are cylindrical
nanostructures with stacked graphene layers that have the forms of cones,
cups, or plates.
• Important characteristics like high electrical conductivity, excellent mechanical
strength .

9. Polymer-based nanofibers
• Polymer-based fibers are used in different areas, such as garments, fishing nets,
cigarette filters, air conditioner filters, surgical masks, heart valves, and vascular
grafts.
• The most popular organic fibers are nanofibers made of polyacrylonitrile (PAN).
• The catalytic fiber’s degradation function is good when polyacrylonitrile
nanofibers are used as carriers.
• PAN nanofibers are also used to make electrodes, antifungal medications, and
adsorbent materials.

10. Composite nanofibers
• Composite nanofibers often integrate polymers, ceramics, metals, or carbon-
based materials. This combination can improve mechanical strength, thermal
stability, and electrical conductivity.
• The characteristics of composite nanofibers are a large surface area, small pore
size, resistance to high temperatures, good conductivity, and high cycle stability.
• This type of nanofibers has been used in numerous fields because of their
improved physical and chemical characteristics.
• By incorporating nanoparticles or functional groups, composite nanofibers can be
tailored for specific applications, such as photocatalysis, adsorption, or sensing.

11. TYPES OF POLYMERS
TYPE OF POLYMER EXAMPLE ENCAPSULATED
DRUG
SOLVENT MANUFACTURING
TECHNIQUE
Natural polymer Collagen N-acetylcysteine Hexa-fluoroisopropanol Electrospinning
Alginic acid Moxifloxacin HCl Dissolution
process
Chitosan Ampicillin sodium Trifluoroacetic acid
(TFA)
Electrospinning
Semi-synthetic
polymer
Cellulose nitrate Diclofenac sodium
Penicillamine-D
Water Water Chemical
crosslinking
(Chemical

12. TYPE OF POLYMER EXAMPLE ENCAPSULATED
DRUG
SOLVENT MANUFACTURING
TECHNIQUE
Synthetic Polymers Polyethylene oxide
(PEO)
Teicoplanin
Doxorubicin
hydrochloride
Water Electrospinning
(Physical)
Polyimide (PI) N, N-dimethylace
tamide (DMAC)
Electrospinning
(Physical)
Polyurethane (PU) Donepezil
hydrochloride
N, N-
dimethylformamide
Electrospinning
(Physical)
Poly(3-
hydroxybutyric
acid-co-3- hydroxy
valeric acid) (PHBV)
Metformin
hydrochloride
Water Electrospinning
(Physical)

13. FABRICATION METHODS OF NANOFIBRES
Electro Spinning
• Coaxial electrospinning
• Multi-jet electrospinning
• Bubble electrospinning
• Melt electrospinning

14. Electro Spinning
• This process involves dissolving the drug and polymer in an appropriate solvent.
The solution is then placed in a syringe, and a high voltage is applied.
• A small amount of the polymer solution is drawn out of the syringe, forming a
Taylor cone.
• Increasing the applied voltage further results in the initiation of a charged fluid
jet.
• A stable jet is formed when the charge is increased above a critical voltage, and
there is a balance between the surface tension of the fluid and the repulsive
nature of the charge distribution on the surface of the fluid.

15. • The presence of molecular entanglements in the polymer solution prevents the
jet from breaking into droplets , and when combined with the electrical forces
results in a whip-like motion of the jet, known as bending instability.
• This process typically results in the drawing of a virtually endless fiber with a
nanometer-sized to micrometer sized diameter.
• The final product is a three-dimensional nonwoven mat of entangled Nanofibers
with a high surface area-to-volume ratio.

16. • The process makes use of electrostatic
and mechanical force to spin fibers from
the tip of a fine orifice.
• The orifice is maintained at positive or
negative charge by a DC power supply.
• When the electrostatic repelling force
overcomes the surface tension force of
the polymer solution, the liquid spills out
of the orifice and forms an extremely
fine continuous filament.

17. • digram
Representation of the electrospinning method.

18. • These filaments are collected onto a rotating or stationary collector with an
electrode beneath of the opposite charge to that of the orifice, where they
accumulate and bond together to form nanofiber fabric.
• The distance between the nozzle and the collector generally varies from 15 –30
cm. The process can be carried out at room temperature unless heat is required
to keep the polymer in liquid state. The final fiber properties depend on polymer
type and operating conditions.

19. • A variety of bioactive molecules including anti-cancer drugs, enzymes,
cytokines, and polysaccharides were entrapped within the interior or
physically immobilized on the surface for controlled drug delivery.
• Surfaces of electrospun nanofibers were chemically modified with
immobilizing cell specific bioactive ligands to enhance cell adhesion,
proliferation, and differentiation by mimicking morphology and biological
functions of extracellular matrix.

20. • According to the process for making the polymer, the electrospinning technique
is classified
 Solution electrospinning
 Melt electrospinning
• Electrospinning is the most widely used technology because it is easy, repeatable,
economical, and scalable.

21. • The factors affecting the characteristics of nanofibers are divided into three
groups: process parameters, material parameters and environmental parameters
such as temperature and humidity.
• High voltage, flow rate, and the distance from the Taylor cone to the collector are
process variables that impact the nanofibers morphology.
• The material attributes include molecular weight, polymer concentration, surface
tension, conductivity, and solvent volatility.

22. • Electrospinning cannot dissolve the very low conductivity polymer because there
is no charge on the liquid droplet’s surface for the electric field to act on. The
polymer concentration and molecular weight affect the polymer solution’s
viscosity.
• The size of the droplet generated and the force needed to drive the melt out
depend on the amount of polymer melt escaping, which is indicated by the
nozzle.
• If the nozzle is too small, the polymer solution will be too viscous, and the melt
cannot be pushed out.

23. • An essential component of electrospinning is the surface tension, which depends
on the solvent composition of the solution.
• Solvents play a crucial role in determining the mechanical properties of the
nanofibers.
• Two important considerations are the solvent’s boiling point and the solubility of
the polymer in the solvent.

24. Coaxial electrospinning
• Primarily used to produce nanofibers with a core-sheath structure.
• By using this technique, drugs can be incorporated into the cores of nanofibers to
produce controlled and prolonged drug release. These nanofibers have a large
surface area and a three-dimensional network.
• The core-shell structure of the loaded molecule is protected by this method with
maintaining the biological activities of the pharmaceuticals.
• When the biomolecule is inside the jet during the electrospinning process, its
functionality is increased, and the polymer solution is outside the jet, protecting
the biomolecule. This is one of the essential benefits of coaxial electrospinning.

25. • In this method, the polymer shell aids in
preventing direct contact between the
biomolecule and the outside world. The
core-shell approach maintains prolongs
drug release.
• Due to the distinctive architecture of
coaxial electro spun nanofibers, it is an
improved electrospinning method for
manufacturing composite nanofibers for
effective gene delivery.

26. • This approach produces multilayer structures, such as nuclear (internal) and
envelope (external) structures, which enable many genes to be delivered under
controlled conditions, thus increasing the genes’ bioactivity.
• Coaxial nanofibers for drug delivery have been effectively integrated with
proteins, growth hormones, anti-biotics, and other biological agents.

27. Multi-jet electrospinning
• Designed for manufacturing large nanofibers to boost output and coverage.
• It comprised two steps for creating nanofiber filaments: spinning and drawing
together.
• When the auxiliary electrode was inserted during the formation of spun
nanofiber filaments, the electrostatic field interference between needles is
decreased, leading to either a reduction in beam offsets or an enhancement in
Taylor cone and beam stability.

28. • An electrospinning apparatus with several or
fewer nozzles can produce electro spun
nanofiber jets.
• Using a multi jet electrospinning apparatus,
multicomponent polymers can be electro spun
to create an amalgamation of nanofiber mats
with a consistent thickness and sufficient
dispersibility.
• Using this method, it is also possible to create
mixed nanofiber mats that comprise
multipolymers.

29. Emulsion electrospinning
• It is a quick, cost-effective and potential method for fabricating
electro spun core-shell nanofibers.
• Emulsion electrospinning is a more effective method ,
particularly for modifying the pace at which drugs are released
by controlling the water and oil phases of the emulsions to
achieve the desired drug release.
• Eg. Metformin hydrochloride (MH) or metoprolol tartrate
(MPT) were added to the fibers of poly (ϵ-caprolactone) (PCL)
and poly (3-hydroxybutyric-co-3-hydroxy valeric acid) (PHBV)
using emulsion electrospinning.

30. Bubble electrospinning
• Electrospinning uses electrical forces to break the
surface tension of the resultant bubbles. With moving
air, these bubbles develop on the polymer solution’s
surface.
• Taylor cones are created by electrical forces, which are
used to create fibers. The shape and size of the bubble
impact the surface tension .
• Nanofibers having a diameter of 100 nm are created
using aqueous solvent bubble electrospinning.
• Eco-friendly nanofibers have a minimum diameter of
only 46.8 nm and are produced using polyvinyl alcohol
(PVA) and water as the solvent .

31. Melt Electrospinning
• When a polymer melt is extruded via
tiny nozzles surrounded by fast-
moving gas, individual sub
microfibers/nanofibers were created.
• Melt blowing may be scaled up by
adding nozzles to reduce costs.
• However, melt-blown fibers are
arbitrarily arranged into nonwoven
layers, in contrast to electrospinning,
which might result in aligned fibers.

32. Characterization
• Geometrical characterization
Geometric properties of nanofibers such as fibre diameter, diameter
distribution, fibre orientation and fibre morphology (e.g. cross-section
shape and surface roughness) can be characterized using scanning electron
microscopy (SEM), field emission scanning electron microscopy (FESEM),
transmission electron microscopy (TEM) and atomic force microscopy
(AFM).
The porosity and pore size of nanofiber membranes are important for
application of filtration, tissue template, protective clothing.
The pore size measurement can be conducted by a capillary flow porometer.

33. a) SEM of PLLA nanofibers b) TEM of elastin-mimetic peptide fibers c) AFM of polyurethane nanofibers

34. • Chemical Characterization
Molecular structure of a nanofiber can be characterized by Fourier
transform infrared (FTIR) and nuclear magnetic resonance (NMR)
techniques.
• Physical characterization
Air and vapor transport properties of electro spun nanofibrous mats
have been measured using an apparatus called dynamic moisture vapor
permeation cell (DMPC) measure both the moisture vapor transport
and the air permeability.

35. APPLICATIONS

36. Drug delivery
• High encapsulation efficiency (EE %), high
drug loading, improved therapeutic index,
markedly reduced side effects, potential
to integrate drug release, and control
over the solution and processing
conditions.

37. Wound healing
• Drug-loaded nanofiber scaffolds are effective due to
their flexibility, drug release effectiveness, and
biocompatibility, allowing damaged tissue regeneration.
• Collagen electro spun nanofiber scaffolds are the most
biomimetic substitute for skin because they encourage
cell development and penetration into the constructed
matrix.
• Eg. Chitosan-graft-poly electro spun nanofibrous mats
have special cell attachment and proliferation
capabilities, making them a suitable replacement for
skin tissue engineering .

38. Contraceptives
• Nanofibres have become a viable option for systemic and loco-regional drug
delivery. In recent years, many researchers have shown a strong interest in
developing vaginal nanofibers for diseases like cancer and infection .
• Nanofibre platforms have been used successfully to deliver drugs directly through
the vaginal mucosa to prevent sexually transmitted diseases (STDs) and as a
contraceptive for unintended pregnancy.
• Eg. The nanofibre mats may be shaped into specific shapes for the best
implantation since they are flexible and free of sharp edges. Compared to
intravenous cisplatin injection, treatment with nanofiber mats dramatically
decreased the size of the cervical tumors.

39. • Tissue engineering
• Electro spun nanofiber scaffolds are highly valued in tissue engineering for
their ability to replicate the natural extracellular matrix (ECM) of various
tissues.
• Their fibrous structure, high surface-to-volume ratio, and tunable porosity
closely mimic the ECM, providing an ideal environment for cell attachment,
proliferation, and differentiation.
• These scaffolds are particularly effective in bone tissue engineering, where
they can replicate collagen, a key component of bone ECM, supporting
osteogenic differentiation and bone formation.
• Additionally, their surface can be easily functionalized to enhance cell
adhesion or deliver growth factors, making them versatile for applications in
cartilage, ligaments, skeletal muscles, skin, blood vessels, and neural tissue
regeneration.

40. Nanofiber products Available in Market

41. REFERENCES
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42. Thank You