This presentation delivers about Physiochemical properties of nanomaterials and its nanotoxicity.

1. Physiochemical Characteristics of Nanomaterials and Their Effects
on Size, Shape, Surface Charge, Solubility, and Surface Coatings
 Arockiya Nisha Arul Thomas
 Department of Nanoscience and
Technology
 Alagappa University, Karaikudi
Done
By
Nanotoxicology

2. What are Nanomaterials?
Nanomaterials are materials with at least one
dimension in the nanoscale range (1-100
nanometers).
Due to their incredibly small size, nanomaterials
exhibit unique properties that differ from their
bulk counterparts.
Nanomaterials have a wide range of applications
in various fields, including medicine, electronics,
and energy.

3. Physicochemical Properties of Nanomaterials
Surface Area: Plays a crucial role in
reactivity, adsorption of molecules, and
catalytic activity.
Surface Chemistry: Functional groups on
the surface can influence interactions with
other materials and biological systems.
Agglomeration State: How individual
nanoparticles cluster together can affect
their behavior and potential toxicity.
Size: Significantly impacts reactivity,
behavior in biological systems, and
overall stability.
Shape: Influences interaction with cells,
targeting specific tissues, and overall
performance.
Surface Charge: Affects dispersion,
interaction with biomolecules, and
cellular uptake.

4. Size and its Effects
Smaller nanoparticles have a higher surface
area to volume ratio, leading to increased
reactivity.
Smaller size allows for easier penetration into
cells and tissues, potentially impacting
biological systems.
Size can influence the overall stability of
nanomaterials, with smaller particles being more
prone to aggregation.

5. Shape and its Effects
The shape of a nanomaterial significantly
influences how it interacts with cells and tissues.
Spheres: The most common shape, spheres
offer minimal interaction points and tend to
have lower cellular uptake compared to other
shapes.
Rods: Due to their elongated form, rods can
have higher cellular uptake and may interact
more effectively with certain cellular
structures.
Tubes: Nanotubes can offer unique properties
like high aspect ratio and can be used for
targeted drug delivery or act as scaffolds for
tissue engineering.
Other shapes: Depending on the
application, various other shapes like
triangles or discs can be engineered,
offering specific advantages in terms of
interaction or function.
The specific shape chosen for a
nanomaterial will depend on the desired
outcome. For instance, if aiming for high
cellular uptake for drug delivery, nanorods
or triangles might be preferable.

6. Surface Charge and its Effects
The surface charge of a nanomaterial affects its dispersion,
interaction with biomolecules, and cellular uptake.
Attraction and Repulsion: Charged nanoparticles attract
oppositely charged molecules and repel similarly charged
ones. This can influence how they interact with proteins,
enzymes, and other biomolecules in the body.
Dispersion: The charge can affect how well nanoparticles
disperse in a liquid. Similar charges tend to repel each other,
preventing clumping and promoting better dispersion.
Cellular Uptake: Charged nanoparticles can be more readily
taken up by cells depending on the cell membrane charge.
Oppositely charged particles may be attracted and
internalized by the cell.

7. Solubility and its Effects
The solubility of a nanomaterial, its ability to dissolve in a
liquid, is influenced by size, shape, and surface charge.
Size: Smaller nanoparticles generally have higher solubility
due to their increased surface area, which allows them to
interact more effectively with solvent molecules.
Shape: Irregularly shaped nanoparticles may pack less
efficiently, leading to potentially higher solubility compared
to perfectly spherical ones.
Surface Charge: Charged nanoparticles can interact with
water molecules through electrostatic forces, influencing
their solubility. Additionally, charged nanoparticles can
attract ions present in the solvent, affecting overall solubility.
The solubility of a nanomaterial determines its behavior in
biological fluids like blood or intracellular environments.

8. Surface Coatings and their Effects
 Surface coatings can be applied to nanomaterials to alter their properties, such as
improving stability, reducing toxicity, or enhancing targeting to specific tissues.
 Improved Stability: Coatings can prevent nanoparticles from clumping together,
improving their dispersion and shelf life.
 Reduced Toxicity: Certain coatings can shield the core material from interacting
with biological systems, potentially reducing unintended side effects.
 Enhanced Targeting: Specific molecules can be attached to the coating, allowing
nanoparticles to bind to particular cells or tissues, improving drug delivery or
imaging applications.
 Functionalization: Coatings can introduce new functionalities to the
nanomaterial, such as making it magnetic for easier manipulation or adding
fluorescent tags for tracking purposes.

9. Effects on Biological Systems
Interactions of Nanomaterials with Biological
Entities:
Nanomaterials interact with various biological entities,
including cells, proteins, and DNA, through physical
and chemical mechanisms. The physiochemical
properties of nanoparticles significantly influence their
cellular uptake, intracellular trafficking, and biological
responses.
Influence of Physiochemical Characteristics:
Size, shape, surface charge, solubility, and surface
coatings impact the toxicity, cellular internalization,
and biodistribution of nanomaterials. Understanding
these effects is essential for assessing the safety and
efficacy of nanomaterial-based products.
Case Studies and Research Findings:
Examples of studies elucidating the relationship
between physiochemical properties and biological
responses will be presented to demonstrate the
importance of considering these factors in
nanotoxicology research.

10. Case Studies: Physiochemical Properties and Biological
Responses
Case Study 1:
• Nanomaterial: Silver nanoparticles (AgNPs) are widely used in various
products due to their potent antibacterial properties.
• Physicochemical Properties: Size and surface coating are crucial factors in
AgNP toxicity.
• Biological Response: Studies have shown that smaller AgNPs with high
surface area exhibit greater antibacterial activity. However, this also
increases their potential to interact with and damage mammalian cells.
Additionally, uncoated AgNPs can release silver ions, which contribute to
their antibacterial effect but may also lead to cytotoxicity.
• Research Findings: This case study emphasizes how size and surface
coating can influence the beneficial (antibacterial) and detrimental
(cytotoxic) effects of AgNPs. By controlling these properties, scientists can
develop safer and more effective AgNP-based antimicrobials.

11. Case Study 2
Mesoporous Silica Nanoparticles for Drug Delivery
 Nanomaterial: Mesoporous silica nanoparticles (MSNs) are porous structures
with potential applications in drug delivery.
 Physicochemical Properties: Pore size and surface chemistry are critical
factors for MSNs.
 Biological Response: The size of the pores in MSNs determines the size of the
molecules they can carry. Additionally, the surface chemistry can be modified
to target specific cells or enhance drug release. For instance, attaching
targeting molecules to the MSN surface can direct them towards diseased cells.
 Research Findings: This case study showcases how pore size and surface
chemistry can be tailored in MSNs to optimize drug delivery. By controlling
these properties, researchers can design MSNs for targeted delivery of various
therapeutic agents.

12. THANK YOU