TY - JOUR A1 - Orts Gil, Guillermo A1 - Natte, Kishore A1 - Drescher, Daniela A1 - Bresch, Harald A1 - Mantion, Alexandre A1 - Kneipp, J. A1 - Ă–sterle, Werner T1 - Characterisation of silica nanoparticles prior to in vitro studies: from primary particles to agglomerates T2 - Journal of nanoparticle research N2 - The size, surface charge and agglomeration state of nanoparticles under physiological conditions are fundamental parameters to be determined prior to their application in toxicological studies. Although silica-based materials are among the most promising candidates for biomedical applications, more systematic studies concerning the characterisation before performing toxicological studies are necessary. This interest is based on the necessity to elucidate the mechanisms affecting its toxicity. We present here TEM, SAXS and SMPS as a combination of methods allowing an accurate determination of single nanoparticle sizes. For the commercial material, Ludox TM50 single particle sizes around 30 nm were found in solution. DLS measurements of single particles are rather affected by polydispersity and particles concentration but this technique is useful to monitor their agglomeration state. Here, the influence of nanoparticle concentration, ionic strength (IS), pH and bath sonication on the agglomeration behaviour of silica particles in solution has been systematically investigated. Moreover, the colloidal stability of silica particles in the presence of BSA has been investigated showing a correlation between silica and protein concentrations and the formation of agglomerates. Finally, the colloidal stability of silica particles in standard cell culture medium has been tested, concluding the necessity of surface modification in order to preserve silica as primary particles in the presence of serum. The results presented here have major implications on toxicity investigations because silica agglomeration will change the probability and uptake mechanisms and thereby may affect toxicity. PB - Springer KW - Silica KW - Toxicology KW - Agglomeration KW - BSA KW - Nanoparticles KW - Characterisation PY - 2011 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/21179 AN - OPUS4-21179 SN - 1388-0764 SN - 1572-896X VL - 13 IS - 4 SP - 1593 EP - 1604 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany