|Moulton, K - MISSISSIPPI STATE UNIV|
|Lovell, F - MISSISSIPPI STATE UNIV|
|Williams, E - MISSISSIPPI STATE UNIV|
|Ryan, P - MISSISSIPPI STATE UNIV|
|Lay, Jr, Donald|
|Jansen, D - VANDERBILT UNIVERSITY|
Submitted to: Journal of Biomedical Optics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2006
Publication Date: January 8, 2007
Citation: Moulton, K., Lovell, F., Williams, E., Ryan, P., Lay Jr, D.C., Jansen, D. 2007. Use of glycerol as an optical clearing agent for enhancing photonic transference and detectionof salmonella typhimurium through porcine skin. Journal of Biomedical Optics. 11(5):054027-1-8. . Interpretive Summary: An assessment of the optical properties of porcine skin suggest that the addition ofhyperosmotic chemical agents (i.e., glycerol) results in no change in absorption of photoniclight, decreases photonic reflectance, increases photonic transmittance and reduces photonicscattering. These qualities of optical clearing agents (glycerol and DMSO) improved the sensitivity of detection of photonic light emitted by transformed (lux) Salmonella typhimurium through porcine skin. Specifically glycerol exhibited a dose-dependence with a substantial increase in photonic detection at concentrations greater than 25% glycerol with immersion. Similar increases in photonic detection occurred after 4 and 8 h treatments with glycerol, as well as a return to pre-treatment values for treated skin rehydrated after soaking in PBS.Addition of DMSO (concentrations greater than 30 %) as a carrier for Optical Clearing Agentsdid not have an appreciable effect on improving the detection of photonic emissions. To this end, glycerol and glycerol + DMSO are effective optical clearing agents for increasing photonicdetection through porcine skin to enhance the sensitivity of biophotonic models aimed at thedetection of Salmonella or other photon emitting experimental paradigms. This new technology will aid scientists in discovering how Salmonella infects swine.
Technical Abstract: The objective of this study was to evaluate glycerol (GLY) and GLY+DMSO (dimethyl sulfoxide) to increase photonic detection of transformed Salmonella typhimurium (S.typh-Lux) through porcineskin. A 96-well plate containing S. typh-lux was imaged for 5 min as a control reference usinga CCD camera. Skin was placed on the plate containing S. typh-lux, imaged (5 min) and then treated with PBS, GLY, DMSO, GLY+DMSO in a dose- and time-dependent manner and re-imaged (5min). The percent of photonic emissions detected (treated or untreated skin relative to no skin controls) were used for analysis. Treatment for 4 h with 50% GLY-PBS and 50:30:20%GLY:DMSO:PBS increased photonic detection (P<.05) compared to untreated skin, 100% PBS or30:70% DMSO:PBS. Ratios of DMSO (10, 20, 30, 40, and 50%) in the presence of 50% GLY demonstrated that DMSO at 20 and 40% increased photonic detection (P<.05) compared to 10% DMSOand 50% GLY:PBS. These data indicate that GLY and GLY+DMSO are effective optical clearing agents on skin when treated for 4 h to increase detection of emitted photons. Clearing agents such as GLY have potential to minimize the effects of skin tissue as one of the photontransmittance barriers (skin, fat, muscle and membranes) in vivo.