1. 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, 70813
2. 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
References
1. M. M. Tian, W. Feng, J. J. Ye and Q. Jia, Anal. Meth., 2013, 5, 3984–3991
2. A. Weir, P. Westerhoff, L. Fabricius, and Natalie von Goetz, Environ Sci Technol. 2012,
46, 2242–2250
3. A. Wise, K. O’Brien, and T. Woodruff, Environ. Sci. Technol. 2011, 45, 51-60
4. P. Liang, B. Adhyaru, W. L. Pearson, and K. R. Williams, Journal of Chem Ed. 2006, 83,
294
5. W. Sun, Y. Du, J. Chen, J. Kou, and B. Yu, Journal of Lum. 2009, 129, 778- 783
6. 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
E2
Recovery (%)
E2 spiked
(nmoles)
E2 recovered
(nmoles)
Adsorption
Capacity
(ng
E2/mgTiO2)
DI Water 2.0% 16 0.33 89ng/mg
DI Water Blank 0 0 0 0
Aquatic Biome 3.5% 16 0.60 150 ng/mg
Aquatic 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 VisFig. 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
Add
Ethyl Acetate
Vortex
Centrifuge
Incubate
Extract Organic
Layer
Quantify 17β-Estradiol
Using CE
Dry Down
Reconstitute
Fig. 4 A picture of the prototype. It consists of a pinched capillary in
between two magnets.
y = 14.0x - 111
R² = 0.998
0
500
1000
1500
2000
2500
3000
0 100 200 300
PeakArea(Au)
Concentration (nM)
17β-Estradiol Calibration Curve
y = 14.0x - 111
R² = 0.998
0
500
1000
1500
2000
2500
3000
0 100 200 300
PeakArea(Au)
Concentration (nM)
17β-Estradiol Calibration Curve
y = 14.0x - 111
R² = 0.998
0
500
1000
1500
2000
2500
3000
0 100 200 300
PeakArea(Au)
Concentration (nM)
17β-Estradiol Calibration Curve