This document discusses nanoparticles in cosmetics and health. It describes how inorganic nanoparticles like TiO2 and ZnO provide sun protection by absorbing UV and visible light. Metal nanoparticles can form colored suspensions useful for applications like sunscreen, medical devices, and art. Silver nanoparticles in particular are known for their antibacterial properties and are used in products like wound creams and washing machines, though free silver ions are toxic. Overuse of sunscreen can cause vitamin D deficiency while protecting skin from sun exposure.

1. Chemistry in every day Life
Nanoparticles in Cosmetics and
Health
Dr. Christoph Sontag
SC 2201
facebook.com/up.chemistry
UP Oct. 2015

3. •Sun protection by TiO2 and ZnO
 Spectrum of visible and uv light
 UVA and UVB light effects
 Absorption and Emission
 Organic and inorganic sun protection agents
•Color effects of nano sized particles
 Production of silver and gold nanoparticles
 Interaction of nanoparticles with light
 Use of gold particles in artistic works
•Health effects of nanoparticles
 Antibacterial effect of silver particles
 Effects of silver and gold nanoparticles in health science

6. http://www.slideshare.net/951384/nanotechnology-in-sunscreen-uv-
protection

7. http://www.slideshare.net/951384/nanotechnology-in-sunscreen-uv-
protection

8. http://fashionhoster.com/sun-protection-factor-calculation-selection-tips/#
SPF (sun protection factor)
= the factor how much longer someone can stay in the
sunshine until reddening of the skin occurs

10. Higher factors than 30
do not add more
protection
In addition look for “+”
for UV-A protection
(also called
“sunblock”)

11. Five things worth knowing about nanoparticles and
sunscreens
https://www.youtube.com/watch?v=VV0cCg4clMw
Video Clip Demonstration:

12. Down-side of sun protection: Vit.D deficiency
• Vit.D prevents Osteomalacia in adults (weak bone
and muscle)
• It maintains a healthy immune system
• Sunscreen may create deficiency of vitamin d
• Skin needs sun exposure a couple of times per
week for good vitamin d levels
http://www.sun-protection-and-you.com/vitamin-d-deficiency.html

13. Organic and inorganic substances
for sunprotection

14. Sun Protection by organic substances
Absorbs UVA and degrades
-> delocalized pi-electrons over 12 atoms
In general: alternating single and double bonds
(“conjugated bonds”) over a long distance allow
electrons to absorb (light)energy easily !

16. Compare ZnO particles
Mechanical grinded ZnO powder
ZnO by chemical reaction

17. Chemically produced ZnO NP
Zn(CH3COO)2 + 2 NaOH
Zn(OH)(CH3COO) + Na(CH3COO)
Zn(OH)2+ Na(CH3COO)
ZnO
- H2O

18. Influence of particle size on appearance
http://www.slideshare.net/951384/nanotechnology-in-sunscreen-uv-
protection

19. Physical methods by Nano Particles

20. TiO2 and ZnO are like semiconductors –
UV light can be absorbed

21. Calculate band gap energy from UV
Absorption of light energy at 400 nm
-> E = h ν = h c/λ in eV
(Constant h * c = 1.24 eV * μm)
=> E = 1.24 / 0.4 eV = 3.1 eV

22. “Natural” SPF
How to make all-natural sunscreen
https://www.youtube.com/watch?v=zskLjTjktfg

23. “Whitening”
Hydroquinone is effective,
but can lead to formation
of benzoquinone, which
can cause cancer !!
Vitamin C is a better
alternative but not as
effective.2% Hydroquinone

24. Colors of NP
Demo: create Ag NP from AgNO3
Ag+ + NaBH4 + H2O  Ag + Na+ + B(OH)3

25. How to make Au NP
TechNyou Education- Making Gold Nanoparticles
https://www.youtube.com/watch?v=JLrn6AsKfuk

26. surface plasmon resonance (SPR)
http://nanocomposix.com/pages/plasmonics
surface plasmonc
resonance where
the free conduction
electrons in the
metal nanoparticle
are driven into
oscillation due to
strong coupling with
incident light.

27. Absorption
maximum is
size dependent

28. Nanoparticles in Art works
http://www.smithsonianmag.com/history/this-1600-year-old-goblet-shows-
that-the-romans-were-nanotechnology-pioneers-787224/?no-ist

29. Antibacterial effects
Ag and ZnO NP
Test for inhibition
of bacterial
growth
http://article.sapub.org/10.5923.j.nn.20120206.03.html

30. Effect on bacterial cell walls
http://www.inbiochem.com/compresa-lazione-battericida-delle-nanoparticelle-
dargento/

32. Drawbacks for the use of Ag NP
Ag NP are toxic for aquatic life, so it is not a very
good idea to use it in washing machines or
other products that cause water contamination
http://www.wsj.com/articles/
SB114955908525572199

33. Summary
• Sun protection by inorganic particles like ZnO is superior
over organic chemicals
• For sun protection a SPF greater than 30 is not useful
• Over-use of sun protection can cause Vit.D deficiency
• Skin-whitening can be harmful, esp. using Hydroquinone
• Metal NP often form colored suspensions, useful for
optical devices, medical applications and art
• Especially Ag NP are known for antibacterial activity and
are use in wound cremes, textiles, body care products and
washing devices – though the released Ag+ ions are toxic to
micro organisms

34. Absorption and Emission