Rapid Elemental Analysis of Human Fingernails Using Laser-Induced Breakdown Spectroscopy
Elemental analysis of human fingernails is conducted using Laser-Induced Breakdown Spectroscopy (LIBS) to diagnose and monitor zinc deficiency in the body. Zinc deficiency is a significant health issue globally, affecting billions of people. By utilizing LIBS technology on fingernail samples, researchers aim to provide a real-time biomedical assay for assessing overall zinc concentration, crucial for addressing health concerns related to zinc deficiency. This innovative approach has the potential to revolutionize healthcare interventions for a widespread and critical issue.
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1 RAPID ELEMENTAL ANALYSIS OF HUMAN FINGERNAILS USING LASER-INDUCED BREAKDOWN SPECTROSCOPY Vlora A. Riberdy Department of Physics University of Windsor Windsor, Ontario
2 Acknowledgements Lab Group: Alexandra Paulick, Dylan Malenfant, Anthony Piazza, Derek Gilles Collaborators: Dr. Chris Frederickson- Neurobiotex, Galveston, TX, Dr. Matthieu Baudelet- University of Central Florida- CREOL, Orlando, FL
3 Motivation for this Project ~25 receptors Zinc deficiency is the leading cause of death among toddlers worldwide. It is also a leading cause of weakened immunity in the elderly. Copenhagen Consensus (8 Nobel Laureates) says: Zinc supplementation is the number ONE most cost- effective move to improve world health. (2-3 billion people deficient worldwide). Frederickson et al., Nature Neuroscience, 2003
4 How do we diagnose and monitor zinc deficiency & remediation in 2-3 billion people ? Can LIBS do this? Why not fingernail zinc? Zinc in the fingernails has been shown to represent the overall zinc concentration in the body. Need a real-time biomedical assay
5 What is LIBS? Intense laser pulse interacts with the target material and energy is absorbed. Energy absorbed results in heating and vaporization of the material. Matter from the surface is removed and a vapor is formed. Laser pulse is still incident on the vapor. Energy is absorbed, inducing heating and plasma formation (with temperature of 10,000 - 20,000 K). As the plasma cools, atoms/ions/molecules decay by spontaneous emission. Light is collected and dispersed by the spectrometer. Resulting spectrum is analyzed to identify elements present in the target material. a) b) c) d)
6 Preparation of Nails Nail clippings of the index, middle and ring fingers (both right and left hands) of 5 subjects were taken a total of 6 nail clippings per subject. Clippings were cleaned with acetone in an ultrasound bath for 10 minutes and allowed to dry for 20-30 minutes. Clippings are cut into approximately 2 mm by 1 mm fragments to provide a flat target.
7 Data Acquisition 1064 nm Nd:YAG laser operating at 10 Hz with pulse energy = 5 mJ. Shot in an argon environment Data was taken using 10 laser pulses per location and 5 locations were averaged to make one spectrum. (50 laser shots per spectrum). Studies were performed to optimize zinc SNR: o Camera delay time = 1 s o Camera gate width = 5 s o Amplification = 2000
8 Element Mean (ppm) Std.Dev. Typical Nail Components Mg 570.8 511.5 Al 837.4 427.2 Si 974.3 594.1 P 1035.2 597.8 S 24810 8776 Cl 1770.2 1121.9 C247.9 K 831.9 666.1 Ca 2311.6 1448.3 Fe 128.6 69.6 Ni 5.1 2.1 Cu 20.8 20.8 Zn 151.7 74.8 Olabanji et al. Nuc. Instrum. Methods Section B: Beam Interactions with Materials and Atoms, 2005 Ca393.4 Ca396.8 Mg279.6 Mg280.3 Mg285.2 Zn202.5 Zn206.2 Zn213.8 Ca422.7 Ar Ca315.7 Ca317.9 Na589.0 Na589.6 CN Ar Farren, Shayler, Ennos, The Journal of Experimental Biology, 2004 Wavelength (nm)
9 Observed Zinc Lines ZnII 202.547 ZnII 206.2 ZnI 213.855
10 Results Individual Nail Comparison 1600 Index Middle Ring 1400 1200 Average ZnII LIBS Intensity 1000 800 600 400 200 0 1L 1R 2L 2R 3L Sample 3R 4L 4R 6L 6R Each bar is an average of 10 spectra. Error bars are the standard deviations of those measurements. There is no statistical difference between the 3 fingers for each sample.
11 Comparison Between Hands Each value is an average of 30 spectra 1500 laser shots 1400 1200 Average ZnII LIBS Intensity 1000 Measurements from left and right hands agree with each other for each sample group left and right hands together for one measurement per patient 800 600 400 200 Subject Comparison 0 1400 1L 1R 2L 2R 3L Sample 3R 4L 4R 6L 6R 1200 Average ZnII LIBS Intensity 1000 Each value is an average of 60 spectra 3000 laser shots in total. 800 600 Goal: We want one measurement per patient. 10 shots in 1 location, with 1 resulting spectrum. 400 200 0 S1 S2 S3 S4 S6 Sample
12 LIBS vs. SIDMS Speciated isotope dilute mass spectrometry Nail clippings from each subject sent to Texas Is the zinc intensity value proportional to the actual concentration of zinc? LIBS Intensity Value Actual Zinc Concentration
13 Effects of Normalization to Carbon Normalization can reduce the uncertainty in the measurements Ratio of the lines should be stable ZnII LIBS Intensity Sample Comparison- 6 Nails/Sample Subject Comparison using LIBS Intensity 6 Nail Average- Sample Comparison Normalized Subject Comparison 1400 0.012 1200 0.010 Average ZnII LIBS Intensity 1000 0.008 ZnIISUM/C247 800 0.006 600 0.004 400 200 0.002 0 0.000 S1 S2 S3 S4 S6 S1 S2 S3 S4 S6 Sample Sample
14 Future Work Influence of nail preparation buffing the nail to smooth out the surface before ablation Tests to determine the change in zinc concentrations over time shooting along the direction of nail growth Larger subject sizes are being acquired PLS regression multivariate analysis to discriminate between normal and zinc deficient nails Goal: To have one measurement per patient that determines whether they are zinc deficient or not.
15 Thank You to My advisor Dr. Steven J. Rehse University of Windsor Outstanding Scholars Program NSERC USRA NSERC NSERC Canada Foundation for Innovation- Leaders Opportunity Fund Canada Foundation for Innovation GLIER- University of Windsor
