Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures

Characterization of estrogen and androgen activity of food contact materials by different in vitro bioassays (YES, YAS, ERα and AR CALUX) and chromatographic analysis (GC-MS, HPLC-MS).

Endocrine active substances (EAS) show structural similarities to natural hormones and are suspected to affect the human endocrine system by inducing hormone dependent effects. Recent studies with in vitro tests suggest that EAS can leach from packaging into food and may therefore pose a risk to human health. Sample migrates from food contact materials were tested for estrogen and androgen agonists and antagonists with different commonly used in vitro tests. Additionally, chemical trace analysis by GC-MS and HPLC-MS was used to identify potential hormone active substances in sample migrates. A GC-MS method to screen migrates for 29 known or potential endocrine active substances was established and validated. Samples were migrated according to EC 10/2011, concentrated by solid phase extraction and tested with estrogen and androgen responsive reporter gene assays based on yeast cells (YES and YAS) or human osteoblast cells (ERα and AR CALUX). A high level of agreement between the different bioassays could be observed by screening for estrogen agonists. Four out of 18 samples tested showed an estrogen activity in a similar range in both, YES and ERα CALUX. Two more samples tested positive in ERα CALUX due to the lower limits of detection in this assay. Androgen agonists could not be detected in any of the tested samples, neither with YAS nor with AR CALUX. When testing for antagonists, significant differences between yeast and human cell-based bioassays were noticed. Using YES and YAS many samples showed a strong antagonistic activity which was not observed using human cell-based CALUX assays. By GC-MS, some known or supposed EAS were identified in sample migrates that showed a biological activity in the in vitro tests. However, no firm conclusions about the sources of the observed hormone activity could be obtained from the chemical results

Estrogen and antiestrogen activities of identified substances in the YES and ER CALUX.

<p>CAS#… Chemical Abstracts Service Number.</p>a<p>… inhibition of human U2-OS osteosarcoma cell growth at higher concentrations.</p>b<p>… inhibition of yeast growth at higher concentrations.</p

Identification of substances in migrates of samples which were hormone active in bioassay analysis.

a<p>… identification of the substance verified by comparison to a standard.</p>b<p>… identification of the substances by database comparison of mass spectra, not verified by comparison to a standard.</p><p>LOD…Limit of detection.</p><p>LOQ…Limit of quantification.</p><p>CAS#… Chemical Abstracts Service Number.</p

Food simulants for the migration of packaging samples.

a<p>Sample was previously tested by Kirchnawy et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100952#pone.0100952-Kirchnawy1" target="_blank">[1]</a> using the YES.</p>b<p>Migration was done at 60°C for 10 days.</p

Androgen and antiandrogen activity of migrates from plastic samples.

a<p>… inhibition of response to DHT in undiluted samples.</p>b<p>… inhibition of yeast growth in undiluted samples.</p><p>−… no antiandrogen activity was detected.</p><p>+… antiandrogen activity in the range of the activity of 0.01 to 0,1 mg/l flutamide.</p><p>++… antiandrogen activity in the range of the activity of 0.1 to 1 mg/l flutamide.</p><p>+++… antiandrogen activity in the range of the activity of 1 to 10 mg/l flutamide.</p

Estrogen and antiestrogen activity of migrates from plastic samples.

a<p>… inhibition of response to 17β-estradiol in undiluted samples.</p>b<p>… inhibition of yeast growth in undiluted samples.</p><p>−… no antiestrogen activity was detected.</p><p>+… antiestrogen activity in the range of the activity of 0.01 to 0.1 mg/l 4-OHT.</p><p>++… antiestrogen activity in the range of the activity of 0.1 to 1 mg/l 4-OHT.</p><p>+++… antiestrogen activity in the range of the activity of 1 to 10 mg/l 4-OHT.</p

GC-MS-Analysis: Total Ion Chromatogram (TIC) of a migrate of sample CF 1.

<p>GC-MS-Analysis: Total Ion Chromatogram (TIC) of a migrate of sample CF 1.</p