Damjana Drobne University of Ljubljana, Biotechnical FacultyDepartment of Biology, SLOVENIA

E-mail: Damjana.Drobne@bf.uni-lj.si

Nanosized ZnO and nano TiO2:

bioavailability and bioaccumulation

CONFERENCE ON NANO-SAFETY22.-24. April 2009, Ljubljana, Slovenia

Research group for nanobiology and nanotoxicology

Dept. Biology, Biotechnical faculty, Uni Ljubljana

Damjana Drobne; Vladka Lešer; Janez Valant; Živa Tkalec Pipan;Marjetka Kralj Kunčič; Sara Novak, student; Tea Romih; student ______________________________________________

National Institute of chemstryAnita Jemec ______________________________________________

Faculty for computer and information science, Uni LjubljanaJernej Zupanc

J1-9475 (C) Elaboration and evealution of a single species toxicity test for nanoparticles with a terrestrial isopod evaluation and Izdelava in vrednotenje testa strupenosti (basic research project), Slovenian Research Agency 2006-2009

Aim of work

…. to study interactions between nanoparticles and biological systes

A terrestrial isopod, a model invertebrate organism

In vivo and in vitro biological system

Lipid vesicles

... studding toxicity of metal pollutants and pesticides present in the environment.

Our past experiences

Present challanges

Interactions between nanoparticles and biological systems.

.. .biological potential of nanosized metal oxides

+

Photo: M. Bele, Institute of chemistry, Ljubljana

Chemicals affect target molecules or interfere with different intracellular compartments. The effect is propagated upwards to higher levels of biological complexity (cells, tissue, organs, organism) and it is manifested as toxic response.

What about nanoparticles?

1) One hypothesis is that nanoparticles interact firstwith cell membrane!

A consequesnce is….

… cells are affected, but nanoparticles were not detected inside the cells (nanoTiO2).

Photo: J. Valant

2) The other opened question is: are nanoparticle bioavailable; do they bioaccumulate?

By L.Ziccardi, M. McArdle, Y. Lowney, J. Tsuji

?

Do ZnO nanoparticles accumulate?

Our work

- model organism, terrestrial isopod P. scaber

- food exposure to nanoparticles for 4 weeks

- comparison among bioaccumulation of - nano ZnO, - macropowder ZnO

- ZnCl2

Background

• terrestrial isopods accumulate high amounts of meals (Zn, Pb, Cu, Fe etc). in their tissue

• a lot of knowledge already exist on the accumulation pattern and accumulation strategy of metals if offered as soluble salts

-

metal analyses in whole organism by AAS

+Four weeks feeding on Nanoparticel, macropowsder or ZnCl dosed food

concentrations of Zn in the body

Experimental set up

Background knowledge: FIB/SEM,

Photo: F.Tatti, FEI

Scanning electron micrograph of macropowder of ZnO.

Scanning electron micrograph of nanosized ZnO

Results

• no diffrences in amount of accumulated Zn among groups

control Zn2000n zn2000M znCl2000 Zn5000n zn5000M ZnCl50000

200

400

600

800

1000

1200

$

&

& glede Zn 2000 M $ glede ZnCl 2000

*

*

# glede Zn 2000 n * glede na kontrolo

Exposure concentration (g/g food)

Am

ou

nt o

f Z

n (g

/g d

ry w

eig

ht)

TOTAL BODY

*#

By Ž. Pipan Tkavec, D. Drobne, A.Jemec ,T.Romih, P.Zidar, M.Bele

2000 µg/g

5000 µg/g

Discussion

• we are not able to answere the question about nanoaprticle bioavailability or bioaccumauation pottential

• the fact is that when nanosized or macrosized ZnO is ingetsed an equal prtion of Zn is accumulated as when ZnCl2 is inegested

Present/Future direction of research

• investigation of accumulation of other nanparticles with lower dissolution rates; for example Cu and Ag nanoparticles

• Investigation of interaction between membranes and nanoparticles

Photo by J.Zupanc

Computer aided analysis of lipid vesicles shape transformations after incubation with nanoparticles.

Publications:

- DROBNE, Damjana, JEMEC, Anita, PIPAN, Živa. In vivo screening to determine hazards of nanoparticles: nanosized TiO2. Environ. pollut. ,2009, issue 4, vol. 157, str. 1157-1164

- JEMEC, Anita, DROBNE, Damjana, REMŠKAR, Maja, SEPČIĆ, Kristina, TIŠLER, Tatjana. Effects of ingested nano-sized titanium dioxide on terrestrial isopods Porcellio scaber. Environ. toxicol. chem., 2008, vol. 27, no. 9, str. 1904-1914,

- JEMEC, Anita, DROBNE, Damjana, TIŠLER, Tatjana, SEPČIĆ, Kristina. Biochemical biomarkers in environmental studies-lessons learnt from enzymes catalase, glutathione S-transferase and cholinesterase in two crustacean species. Environ. sci. pollut. res. int., 2009, 11 str.,

Thank you for your attention!