Enhanced Selectivity by Passivation: Molecular Imprints for Viruses with Exceptional Binding Properties.

Inspired by the recognition processes found in biology such as enzyme-substrate and antibody-antigen interactions, synthetic systems with comparable molecular recognition properties have been investigated during recent years based on molecular imprinting strategies. While materials with recognition capabilities for small molecules (i.e., with low molecular weight) have achieved substantial advancements, the synthesis of molecularly imprinted materials with virus recognition properties remains challenging to date. Likewise, protein-surface and protein-protein interactions are essential for a wide variety of biological applications in biotechnology. In biological sensor technology the coating of surfaces to prevent nonspecific adsorption interactions plays an important role. Particularly, polyethylene glycol (PEG) stands out for its high performance in preventing proteins from nonspecifically interactions. However, blocking agents such as the protein bovine serum albumin (BSA) can also be useful as unspecific binding prevention agents for passivation, without modification of the surface. Herein the influence of blocking agents as unspecific reaction components is investigated on the enhancements of selectivity from adenovirus-imprinted particles, whereas adenovirus was used as target species in molecular imprinting. Furthermore, quantitative polymerase chain reaction (qPCR) was used for the first time as virus quantification approach in this context.

Does formaldehyde induce aneuploidy?

Formaldehyde (FA) was tested for a potential aneugenic activity in mammalian cells. We employed tests to discriminate between aneugenic and clastogenic effects in accordance with international guidelines for genotoxicity testing. The cytokinesis-block micronucleus test (CBMNT) in combination with fluorescence in situ hybridisation (FISH) with a pan-centromeric probe was performed with cultured human lymphocytes and the human A549 lung cell line. FA induced micronuclei (MN) in binuclear cells of both cell types under standard in vitro test conditions following the OECD guideline 487. FISH analysis revealed that the vast majority of induced MN were centromere negative, thus indicating a clastogenic effect. A similar result was obtained for MN induced by γ-irradiation, whereas the typical aneugens colcemid (COL) and vincristine (VCR) predominantly induced centromere-positive MN. Furthermore, COL and VCR clearly enhanced the MN frequency in mononuclear lymphocytes in the CBMNT, whereas such an effect was not observed for γ-irradiation and FA. In experiments with the Chinese hamster V79 cell line, the aneugens COL and VCR clearly increased the frequency of tetraploid second division metaphases, whereas FA did not cause such an effect. Altogether, our results confirm the clastogenicity of FA in cultured mammalian cells but exclude a significant aneugenic activity.

Assessment of genotoxic effects and changes in gene expression in humans exposed to formaldehyde by inhalation under controlled conditions.

Forty-one volunteers (male non-smokers) were exposed to formaldehyde (FA) vapours for 4 h/day over a period of five working days under strictly controlled conditions. For each exposure day, different exposure concentrations were used in a random order ranging from 0 up to 0.7 p.p.m. At concentrations of 0.3 and 0.4 p.p.m., four peaks of 0.6 or 0.8 p.p.m. for 15 min each were applied. During exposure, subjects had to perform bicycle exercises (∼80 W) four times for 15 min. Blood samples, exfoliated nasal mucosa cells and nasal biopsies were taken before the first and after the last exposure. Nasal epithelial cells were additionally sampled 1, 2 and 3 weeks after the end of the exposure period. The alkaline comet assay, the sister chromatid exchange test and the cytokinesis-block micronucleus test were performed with blood samples. The micronucleus test was also performed with exfoliated nasal mucosa cells. The expression (mRNA level) of the glutathione (GSH)-dependent formaldehyde dehydrogenase (FDH, identical to alcohol dehydrogenase 5; ADH5; EC 1.2.1.46) was measured in blood samples by quantitative real-time reverse transcription-polymerase chain reaction with TaqMan probes. DNA microarray analyses using a full-genome human microarray were performed on blood samples and nasal biopsies of selected subgroups with the highest FA exposure at different days. Under the experimental conditions of this study, inhalation of FA did not lead to genotoxic effects in peripheral blood cells and nasal mucosa and had no effect on the expression of the FDH gene. Inhalation of FA did also not cause alterations in the expression of genes in a microarray analysis with nasal biopsies and peripheral blood cells.