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Assessment of the Affinity of Titanium Dioxide Nanoparticles to Estradiol
Nicholas C. Sargent-Johnson1, Cassandra L. Crihfield2, Vincent T. Nyakubaya2 and Lisa A. Holland2.
1. Department of Chemistry, Southern University and A&M College, Baton Rouge, LA, 708132. C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV,
26506
Titanium dioxide nanoparticles capture and concentrate low concentrations of 17β-estradiol in the presence of proteins
Hypothesis
•17β-estradiol and albumin bind to each other [4]• Titanium dioxide and albumin bind to each other [5]•Titanium Dioxide and UV light together will degrade 17β-estradiol [6]
Background Information
Experimental
Results
Conclusions
Acknowledgements
Capillary Electrophoresis
Capillary Electrophoresis System with UV-Visible Detection: - Uses low sample volumes- Analyzes groups of analytes in a single sample rapidly
References1. M. M. Tian, W. Feng, J. J. Ye and Q. Jia, Anal. Meth., 2013, 5, 3984–39912. A. Weir, P. Westerhoff, L. Fabricius, and Natalie von Goetz, Environ Sci Technol. 2012,
46, 2242–22503. A. Wise, K. O’Brien, and T. Woodruff, Environ. Sci. Technol. 2011, 45, 51-604. P. Liang, B. Adhyaru, W. L. Pearson, and K. R. Williams, Journal of Chem Ed. 2006, 83,
2945. W. Sun, Y. Du, J. Chen, J. Kou, and B. Yu, Journal of Lum. 2009, 129, 778- 7836. J. Mai, W. Sun, L. Xiong, Y. Liu, and J. Ni, Chemos. 2008, 73, 600-606
Motive
Titanium Dioxide nanoparticles are known endocrine disrupters that are disposed into our water systems where they concentrate and transport contaminants such as 17β-estradiol.[1-2] Areas known to have these contaminants have increased occurrences of health issues such as obesity and defects in human reproductive systems.[3]
(A)
Fig. 3 Results. (A) Recovery data for samples (B) Comparison of DI water sample with 17β-estradiol and without 17β-estradiol (C) Comparison of BSA sample with 17β-estradiol and without 17β-estradiol (D) Comparison of aquatic biome samples with 17β-estradiol and without 17β-estradiol
(B) Electropherogram for DI Water Samples
(C) Electropherogram for Albumin Samples
Fig. 2 (A) Capillary Electrophoresis System by Beckman Coulter and (B) a schematic of how the system works.
(A) (B)
A C
HPVS
Sample Experiment Control
Deionized Water 1.0 mg TiO2 + DI H2O + 4.36µg 17β-estradiol
1.0 mg TiO2 + DI H2O
Albumin(BSA)
1mg TiO2 + Albumin + 4.36µg 17β-estradiol
1mg TiO2 + Albumin
Aquatic Biome 1mg TiO2 + Aquatic Biome + 4.36µg 17β-estradiol
1mg TiO2 + Aquatic Biome
Tab. 1 Description of experimental variables and controls.
I would like to acknowledge the NanoSafe program and the Holland Research Group. Thank you for the support and mentorship.
Sample E2Recovery (%)
E2 spiked (nmoles)
E2 recovered(nmoles)
Adsorption Capacity
(ng E2/mgTiO2)
DI Water 2.0% 16 0.33 89ng/mgDI Water Blank 0 0 0 0
Aquatic Biome 3.5% 16 0.60 150 ng/mgAquatic Biome
Blank 0 0 0 0
BSA 3.7% 16 0.56 160 ng/mg
BSA Blank 0 0 0 0
Fig 1. A diagram of the experiment. 17β-estradiol is the analyte spiked into each sample. Samples include DI water, 0.8 mM albumin, and aquatic biome water.
Detection Window
E2, Area= 1444
E2, Area= 806
E2, Area = 1559
(D) Electropherogram for Aquatic Biome Sample s
1. Magnetic micro-beads are loaded into a pinched capillary
2. TiO2 nanoparticles are loaded
3. E2 in simulated lake water is loaded
- some will stick to the TiO2
4. Deionized water is loaded to rinse salts from E2
5. Methanol is loaded to remove remaining E2
6. E2 that washes off of TiO2
with methanol is quantified via CE-UV Vis
Fig. 5 A diagram of the experiment. This system allows TiO2 nanoparticles to capture estrogens.
Pinched Capillary
Magnet
Magnet
Water
Estrogen
Methanol
Future Work
Future directions include assessing the toxicity of estrogens using a new instrument. This instrument will reduce sample preparation time. The goal is still to detect low concentrations of contaminants in aquatic biomes.
17β-estradiol binds to titanium dioxide nanoparticles without the presence of proteins. However, the adsorption capacity is higher in the presence of albumin and in a real world sample that contains proteins. The affinity between the analyte and nanoparticles is stronger in the aquatic biome because there are more proteins present.
Summary of Recovery Data
SDS
Add Sample to 1mg TiO2
Add 17β-Estradiol
Incubate
Rinse
AddEthyl Acetate
Vortex
Centrifuge
Incubate
Extract Organic Layer
Quantify 17β-EstradiolUsing CE
Dry DownReconstitute
Fig. 4 A picture of the prototype. It consists of a pinched capillary in between two magnets.
0 50 100 150 200 2500
50010001500200025003000
f(x) = 14.0333333333 x − 111.666666667R² = 0.998195928543001
17β-Estradiol Calibration Curve
Concentration (nM)
Peak
Are
a (A
u)
0 50 100 150 200 2500
50010001500200025003000
f(x) = 14.0333333333 x − 111.666666667R² = 0.998195928543001
17β-Estradiol Calibration Curve
Concentration (nM)
Peak
Are
a (A
u)
0 50 100 150 200 2500
50010001500200025003000
f(x) = 14.0333333333 x − 111.666666667R² = 0.998195928543001
17β-Estradiol Calibration Curve
Concentration (nM)
Peak
Are
a (A
u)
