Radiolabelling of engineered silver and titania nanoparticles as a tool for sensitive detection of nanoparticle release from surface coatings


Radiolabelling of engineered silver and titania nanoparticles as a tool for sensitive detection of nanoparticle release from surface coatings

Hildebrand, H.; Franke, K.; Gibson, N.; Cydzik, I.; Simonelli, F.; Bulgheroni, A.; Holzwarth, U.; Bilz, E.; Freyer, A.

Engineered nanoparticles (NPs) such as silver and titania are widely used in consumer products e.g. as functional additives in surface coatings. Due to aging or abrasion of these nanocomposites, particle release becomes likely and further transport e.g. in environmental systems could be assumed. Figure 1 shows results from a worst-case scenario study where NP release was enforced due to the use of a quite labile surface coating and photooxidative degradation of the nanocomposite catalysed by TiO2 anatase NPs. For conventional, more stable nanocomposites, accurate and sensitive detection and quantification of NP release is still a challenge due to the fact that released fractions might be small but nevertheless significant. The application of radiotracers provides the excellent option of “visibility”, traceability and quantification of NPs in complex media. Therefore, different radiolabelling strategies for engineered nanopowders (TiO2 P 25, Evonic Industries, dp = 21 nm; Ag0, Sigma Aldrich, dp < 100 nm) were established using a diffusive introduction of 110mAg radionuclides (t1/2 = 250 d) into Ag0-NPs (Hildebrand & Franke, 2012) and 44Ti radionuclides (t1/2 = 63 a) into TiO2-NPs through a low-temperature annealing procedure. Another radiolabelling strategy is the direct activation of Ag0 and TiO2 nanopowders that was done via proton irradiation using a Scanditronix MC40 cyclotron (Abbas et al. 2010, Holzwarth et al. 2012).
Both methods were tested with respect to labelling yield, achievable activity concentration, pH-dependent stability of the labelling and the influence on NP properties. Results obtained show an appropriate selection of radiolabeling methods suitable for different experimental conditions for NP release studies.

Figure 1: Time-dependent degradation of a polyacrylate TiO2 nanocomposite by UV-A-irradiation (intensity ~ 15 mW/cm2) ;A) original, B) after 2 days (50.000x); C) 4 days, D) 8 days, E) 16 days (75.000x); SEM micrographs: Leibniz Institute for Surface Modification.

Abbas K, Cydzik I, Del Torchio R, Farina M, Forti E, Gibson N, Holzwarth U, Simonelli F, Kreyling W (2010) J Nanopart Res 12:2435–2443.
Holzwarth U, Bulgheroni A, Gibson N, Kozempel J, Cotogno G, Abbas K, Simonelli F, Cydzik I (2012) J Nanopart Res 14:880
Hildebrand H and Franke K (2012) J Nanopart Res 14:1142.

Keywords: engineered nanoparticles; radiolabelling; titania; silver

  • Poster
    NanoSAFE'12, 13.-15.11.2012, Grenoble, France

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Publ.-Id: 17911