Wafer-level detection of organic contamination by ZnO-rGO hybrid-assisted laser desorption/ionization time-of-flight mass spectrometry.

A technique for wafer-level detection of organic contaminations via surface-assisted laser desorption/ionization time-of-flight mass spectrometry was developed. To replace the organic matrix in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, zinc oxide-reduced graphene oxide (ZnO-rGO) hybrid was prepared by a hydrothermal reaction and used as the matrix in the detection of benzo[a]pyrene (B[a]P). By varying the rGO content and the amount of hybrid, the optimal rGO content in the hybrid for the detection of B[a]P was determined to be 4 wt% and the optimal amount of hybrid was 20 ng. The limit of detection of this method was found to be 1.6 × 1014 C atoms cm-2, which is lower than the concentration of residual organic contamination at which serious failure occurs during semiconductor fabrication. This method was also successfully used to detect other aromatic and aliphatic species on a semiconductor wafer. This approach is fast, accurate, simple, and inexpensive compared to other conventional methods, and can be used to identify localized micro-contamination in the semiconductor industry.

Toxic and adjuvant effects of silica nanoparticles on ovalbumin-induced allergic airway inflammation in mice.

BACKGROUND: Silica nanoparticles (SNPs) can easily enter in respiratory system via inhalation because of their low molecular weight and ease of dispersion. Toxicity and adverse effects of SNPs vary according to the physical characteristics of the particle. METHODS: To evaluate the toxic and adjuvant effects of 3 types of SNPs in the airway system, six-week-old female BALB/c mice were intranasally administered 3 types of SNPs (spherical [S-SNP], mesoporous [M-SNP], and polyethylene glycol-conjugated [P-SNP]) alone or SNPs/ovalbumin (OVA), three times weekly for 2 weeks. Airway hyper-responsiveness (AHR), bronchoalveolar lavage fluid (BALF), cytokine levels, and histology of the lungs were analyzed. RESULTS: The S-SNPs/OVA group and M-SNPs/OVA group showed significant AHR, compared to the control group. Among all SNP-treated groups, the group administered SNPs/OVA showed greater inflammatory cell infiltration in BALF, extensive pathological changes, and higher cytokine levels (IL-5, IL-13, IL-1ß, and IFN-γ) than those administered SNPs alone or saline/OVA. CONCLUSION: Exposure to SNPs alone and SNPs/OVA induced toxicity in the respiratory system. SNPs alone showed significant toxic effects on the airway system. Meanwhile, SNPs/OVA exerted adjuvant effects to OVA of inducing allergic airway inflammation. In particular, M-SNPs showed the most severe airway inflammation in both direct toxicity and adjuvant effect assays. P-SNPs induced less inflammation than the other types of SNPs in both models.

Acute exposure to silica nanoparticles aggravate airway inflammation: different effects according to surface characteristics.

Silica nanoparticles (SNPs) are widely used in many scientific and industrial fields despite the lack of proper evaluation of their potential toxicity. This study examined the effects of acute exposure to SNPs, either alone or in conjunction with ovalbumin (OVA), by studying the respiratory systems in exposed mouse models. Three types of SNPs were used: spherical SNPs (S-SNPs), mesoporous SNPs (M-SNPs), and PEGylated SNPs (P-SNPs). In the acute SNP exposure model performed, 6-week-old BALB/c female mice were intranasally inoculated with SNPs for 3 consecutive days. In the OVA/SNPs asthma model, the mice were sensitized two times via the peritoneal route with OVA. Additionally, the mice endured OVA with or without SNP challenges intranasally. Acute SNP exposure induced significant airway inflammation and airway hyper-responsiveness, particularly in the S-SNP group. In OVA/SNPs asthma models, OVA with SNP-treated group showed significant airway inflammation, more than those treated with only OVA and without SNPs. In these models, the P-SNP group induced lower levels of inflammation on airways than both the S-SNP or M-SNP groups. Interleukin (IL)-5, IL-13, IL-1ß and interferon-γ levels correlated with airway inflammation in the tested models, without statistical significance. In the mouse models studied, increased airway inflammation was associated with acute SNPs exposure, whether exposed solely to SNPs or SNPs in conjunction with OVA. P-SNPs appear to be relatively safer for clinical use than S-SNPs and M-SNPs, as determined by lower observed toxicity and airway system inflammation.