Lung cell fiber evanescent wave spectroscopic biosensing of inhalation health hazards.

Health risks associated with the inhalation of biological materials have been a topic of great concern; however, there are no rapid and automatable methods available to evaluate the potential health impact of inhaled materials. Here we describe a novel approach to evaluate the potential toxic effects of materials evaluated through cell-based spectroscopic analysis. Anchorage-dependent cells are grown on the surface of optical fibers transparent to infrared light. The probe system is composed of a single chalcogenide fiber (composed of Te, As, and Se) acting as both the sensor and transmission line for infrared optical signals. The cells are exposed to potential toxins and alterations of cellular composition are monitored through their impact on cellular spectral features. The signal is collected via evanescent wave absorption along the tapered sensing zone of the fiber through spectral changes between 3,000 and 600 cm(-1) (3,333-16,666 nm). Cell physiology, composition, and function are non-invasively tracked through monitoring infrared light absorption by the cell layer. This approach is demonstrated with an immortalized lung cell culture (A549, human lung carcinoma epithelia) in response to a variety of inhalation hazards including gliotoxin (a fungal metabolite), etoposide (a genotoxin), and methyl methansesulfonate (MMS, an alkylating agent). Gliotoxin impacts cell metabolism, etoposide impacts nucleic acids and the cell cycle, and MMS impacts nucleic acids and induces an immune response. This spectroscopic method is sensitive, non-invasive, and provides information on a wide range of cellular damage and response mechanisms and could prove useful for cell response screening of pharmaceuticals or for toxicological evaluations.

Biologically inspired sensing: infrared spectroscopic analysis of cell responses to an inhalation health hazard.

This work describes the development of a biologically based sensing technique to quantify chemical agents that pose inhalation health hazards. The approach utilizes cultured epithelial cells (A549 human type II pneumocytes) of the lung, exposed to potential toxins and monitored through the noninvasive means of infrared spectroscopy to quantify changes to cell physiology and function. Cell response to Streptolysin O, a cholesterol-binding cytolysin, is investigated here. Infrared spectra display changes in cell physiology indicative of membrane damage, altered proteins, and some nucleic acid damage. Methods to improve cell adhesion through modification of support surface properties are detailed. This spectroscopic approach not only provides a robust means to detect potential toxins but also provides information on modes of damage and mechanisms of cellular response.

Comparison of the sensitivity of three lung derived cell lines to metals from combustion derived particulate matter.

While the effects of inhalation of combustion-derived particulate matter have received extensive study, there remains no reliable means to rapidly quantify inhalation toxicity outside of a laboratory setting. Cell-based biosensors provide a potential solution, but few comparisons have been made of the sensitivity of various cell lines to the wide range of inhalation health hazards that are likely to be encountered. This work compares the response of three immortalized lung cell lines (A549 human epithelia, RLE-6TN rat type II epithelia, and NR8383 rat alveolar macrophages) to metals commonly present in combustion-derived particulate matter. Quantifications of the cell response involved measurement of inhibition of cell culture metabolism (mitochondrial succinate dehydrogenase activity) and cell death (release of lactate dehydrogenase). While these three cell types generally ranked metals in ED50 values similarly (V

Evaluation of toxic agent effects on lung cells by fiber evanescent wave spectroscopy.

Biochemical changes in living cells are detected using a fiber probe system composed of a single chalcogenide fiber acting as both the sensor and transmission line for infrared optical signals. The signal is collected via evanescent wave absorption along the tapered sensing zone of the fiber. We spectroscopically monitored the effects of the surfactant Triton X-100, which serves as a toxic agent simulant on a transformed human lung carcinoma type II epithelial cell line (A549). We observe spectral changes between 2800-3000 cm(-1) in four absorptions bands, which are assigned to hydrocarbon vibrations of methylene and methyl groups in membrane lipids. Comparison of fiber and transmission spectra shows that the present technique allows one to locally probe the cell plasma membrane in the lipid spectral region. These optical responses are correlated with cellular metabolic activity measurements and LDH (lactate dehydrogenase) release assays that indicate a loss of cellular function and membrane integrity as would be expected in response to the membrane solubilizing Triton. The spectroscopic technique shows a significantly greater detection resolution in time and concentration.

Effects of metals Cu, Fe, Ni, V, and Zn on rat lung epithelial cells.

Inhalation of combustion-derived particulate matter can have a variety of negative impacts on human health. Metals are known to play a substantial role in these effects, however, the interactions between cellular responses caused by multiple metals is not well understood. The impact of metals (Zn, Cu, Ni, V, and Fe) individually and in combination on a rat lung epithelial cell line (RLE-6TN) was evaluated. Quantifications involved measurement of inhibition of cell culture metabolism (mitochondrial succinate dehydrogenase activity), cell death, mechanisms of cell death, and cytokine secretion. The ranking of metal toxicity based on TC(50) values is V>Zn>Cu>Ni>Fe. Interactions were observed for exposures containing multiple metals: Zn+V, Zn+Cu, Zn+Fe, and Zn+Ni. Zn appears to diminish the negative impact of V and Cu; has an additive effect with Ni, and has no substantial effect on Fe toxicity.