- Gold nanoparticles were synthesized in two sizes using hydrogen tetrachloroaurate and sodium citrate. Larger nanoparticles (around 0.02 M) were found to be more effective substrates for detecting adenine using Surface-Enhanced Raman Spectroscopy (SERS) on filter paper strip sensors. - Testing showed that strips could detect adenine concentrations in a few seconds using portable materials. Further work should test other DNA/RNA components on the strips and develop an inkjet printing method for quick sensor reproduction. - In conclusion, the strip sensors were a fast, simple method for detecting DNA components and have potential applications in medicine and detecting biological agents if further optimized.

1. RESEARCH POSTER PRESENTATION DESIGN © 2012
www.PosterPresentation
s.com
During the investigation, it was shown that gold nanoparticles of a
larger size (around 0.02 M HAuCl4) and at a certain quantity are
more efficient, when being used as substrates of analytes on lab
filter paper strips, to enhance the detection of Adenine in SERS.
In contrast, particles of a smaller size will have little to no effect
on the reading, as show in Figure 6.
As expected, the process of analyzing the strips on SERS took
only a few seconds using commonly available and portable
materials.
Further work on this investigation should include testing the strips
with other DNA components: Guanine, Cytosine, Thymine, as
well as RNA component Uracil. In addition, the use of an Ink-Jet
printer to quickly reproduce the sensor strips.
• Pedro M. Fierro-Mercado and Samuel P. Hérnandez Rivera (2012) “Highly
Sensitive Filter Paper Substrate for SERS Trace Explosives Detection”
International Journal of Spectroscopy, Vol. 2012, 1-7.
• Huixiang Li and Lewis Rothberg (2004) “DNA Sequence Detection Using
Selective Fluorescence Quenching of Tagged Oligonucleotide Probes by Gold
Nanoparticles” Analytical Chemistry, Vol. 76 (18), pp. 5414-5417.
• http://www.semrock.com/Data/Sites/1/semrockimages/technote_images/fig-9-
sers.gif
• http://sbir.gsfc.nasa.gov/SBIR/successes/images/9-028pic.jpg
• http://2.bp.blogspot.com/_WMdGdPSdn0U/TVEhvTNFl2I/AAAAAAAABIM/
UujDNgsBxWg/s400/gold_noparticle
• http://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/DNA_chemical_st
ructure.svg/300px-DNA_chemical_structure.svg.png
• AGMUS Institute of Mathematics
• National Science Foundation
• Universidad Metropolitana
• Dr. Juan Arratia
• Saturday Academy
• Dr. Oliva M. Primera-Pedrozo
• Dr. Samuel P. Hernandez-Rivera
• Pedro Fierro
• Marcos Rodríguez
• Ricardo Lorenzana
• Gold Nanoparticles have a wide range of applications in
science, particularly for their absorption of light.
• As sensors, they are particularly useful as substrates in the
Surface Enhanced Raman Spectroscopy (SERS) to detect the
energy in chemical bonds.
• This technique allows for detection of specific molecules in
analytes.
• Raman Spectroscopy is a technique that uses photons at
different wavelengths in order to determine the properties of
compounds.
• The atoms in the analytes scatter light from the Raman
emission. This will result in a change in the energy of the
photons, which can be used to characterize the chemical bonds
of the atoms.
• Surface Enhanced Raman Spectroscopy (SERS) is a technique
that produces silver plasmons on the analyte by using a metal
substrate so that it resonates with a metal tip.
• This process greatly enhances the Raman emission, which
makes it ideal to detect low concentrations of compounds.
1Escuela Secundaria de la Universidad de Puerto Rico, San Juan, Puerto Rico
2Colegio Luterano Resurrección, Inc., Carolina, Puerto Rico
3Nanomaterials Science Lab. Universidad Metropolitana, Recinto de Cupey, San Juan, Puerto Rico
Ricardo Rodriguez-Garcia1, Stephanie Chan-Yau2, Marcos Rodriguez3, Ricardo Lorenzana3 ,
Oliva M. Primera-Pedrozo3
Gold nanoparticle printer-strip sensors for detection of DNA
components using SERS: Model of adsorption at 785nm
• Synthesize gold nanoparticles at two sizes and analyze their
effect in the detection of DNA components using SERS.
• Prepare lab-filter paper sensors using gold nanoparticles as
substrates, which will efficiently detect DNA components in a
short amount of time.
• Determine what amount and size of gold nanoparticles is best for
detecting DNA components.
Figure 6: Gold Nanoparticles (HAuCl4 0.01 M) are tested in SERS in liquid using
different concentrations of Adenine and 0.01 M NaCl. (A) First Vial: 1000µL AuNPs.
(B) 1000 µL AuNPs with Adenine 1x10-2 M and NaCl 0.01 M. (C) 1000µL AuNPs
with Adenine 1x10-2 M. (D) Second Vial: 1000µL AuNPs. (E) 1000µL AuNPs with
Adenine 1x10-5 M. (F) 1000µL AuNPs with Adenine 1x10-5 M and NaCl 0.01 M.
Figure 8: SERS test of strips with different amounts of AuNPs (.02 M HAuCl4) and
50µL of adenine. (A) no AuNPs. (B) 50µL AuNPs. (C) 100µL AuNPs. (D) 150µL
AuNPs. (E) 200µL AuNPs. (F) 250µL AuNPs.
Results
Methodology
Acknowledgements
References
Conclusions
Objectives
Introduction
Abstract
Gold Nanoparticles have a wide range of applications in biology,
chemistry, and other related fields. These particles can strongly
absorb light and dissipate it in their surroundings, thus making them
great for manipulating heat. In addition, they are used to deliver
therapeutic agents. Due to their density, they can be utilized as
probes for transmission electron microscopy. As sensors, they are
particularly useful as substrates in the Surface Enhanced Raman
Spectroscopy (SERS) to detect the energy in chemical bonds. This
technique allows for detection of specific molecules in analytes.
Currently, gold nanoparticles are utilized as substrates in sensors to
detect low concentrations of hazardous materials, especially those
relating to explosives, through the use of Surface Enhanced Raman
Spectroscopy (SERS). This process enhances the Raman emission
through the use of metal (Gold) which will resonate with a metal
tip. These properties allowed the development of lab filter paper
strip-based sensors in order to detect DNA components in analytes.
Gold nanoparticles were synthesized using 0.01M and 0.02M
hydrogen tetrachloroaurate (III) trihydrate solution with sodium
citrate tribasic dihydrate (TSC, 1%) as both a reducing agent and
capping agent. For this investigation, the strips were tested with the
DNA component adenine. After obtaining results from SERS, it can
be concluded that the use of larger gold nanoparticles (0.02M of
gold salt) is best to accurately detect adenine. Also, the strip
sensors proved to be a fast and simple method to detect DNA
components, which, if perfected, can be useful for medical
examinations and the detection of biological agents. Further work
on this investigation should include testing on other DNA
components guanine, cytosine, and thymine, as well as RNA
component Uracil.
Figure 2: SERS test
using vial or liquid
Figure 3: SERS test using a
flat surface.
Synthesis:
UHP H2O
Add Sodium
Citrate 1 .0 %
(dropwise)
Purification/Characterization:
Add HAuCl4 trihydrate
0.01M/0.02 M
Gold
Nanoparticles
1 mL of AuNPs in
each centrifuge tube
Centrifuge at
10,000 rpm for
1.0 H
Remove supernatant
and re-disperse in
2-propanol
UV-Visible
Spectroscopy
SERS
Strips-substrate preparationLiquid
30
50
70
90
110
130
150
400 900 1400 1900
Counts
Raman Shift /cm^-1
A
B
C
D
E
F
I
519nm
I 523nm
-0.02
0.18
0.38
0.58
0.78
0.98
1.18
1.38
1.58
1.78
1.98
400 500 600 700 800
Absorbance
Wavelength (nm)
A
B
Figure 5: UV-Visible Spectroscopy of AuNPs at different concentrations. (A) AuNPs
using 0.01 M HAuCl4 trihydrate. (B) AuNPs using 0.02 M HAuCl4 trihydrate.
Figure 7: SERS test of gold nanoparticles (0.02 M HAuCl4 trihydrate) using
1x10-2 Adenine and 0.01 M NaCl. (A) Adenine Bulk. (B) Adenine 1x10-2 M. (C)
AuNPs .02 M. (D) NaCl .01 M. (E) AuNPs with Adenine 1x10-2 M. (F) AuNPs with
Adenine 1x10-2 M and NaCl .01 M.
Figure 1: Gold nanoparticles
Figure 4: DNA molecule
722.813874
735.1245725
0
1000
2000
3000
4000
5000
6000
690 710 730 750 770
Counts
Raman Shift/ cm-1
A
B
C
D
E
F
734.2452369
730.7278945
0
200
400
600
800
1000
1200
1400
1600
1800
2000
640 660 680 700 720 740 760 780 800
Counts
Raman Shift / cm-1
A
B
C
D
E
F
0.02 M- Large nanoparticles
735 cm-1
Figure 9: Model of adsorption
AdenineRaman laser