Tin Oxide Nanoparticles for Electrochemical Studies of Amyloid Peptides

A L E J A NDRA M. DE J E SUS SOTOK E NNY J . CO LO N CO LO NR ISE PR OG R AM

Concepts:• Nanoparticles

• Microscopic material that has physical dimensions ranging between 1-100 nm

Otaño-Rivera W. 2014. Introducción a los Conceptos de la Nanotecnología y su Importancia Científica

• Amyloid Peptides:

• Molecular markers

• Diagnosis and prognosis of Alzheimer’s disease

• Transcription factor

• Anti-microbial activity

• Kinase enzyme activator

http://nanogloss.com/wp-content/uploads/2009/08/white-light-nanoparticles.jpg

Lin Liu. 2013. Electrochemical detection of β-amyloid peptides on electrode covered with N-terminus-specific antibody based on electrocatalytic O2 reduction by Aβ(1-16)-heme-modified gold nanoparticles

Why use nanoparticles?

• Higher surface area

• Higher sensitivity

• Low power consumption

• Development of better materials, devices and systems

• Applications in biomedical, optical and electronic fields

http://www.nap.edu/books/0309084547/xhtml/images/p2000a445g6001.jpg

Lin Liu. 2013. Electrochemical detection of β-amyloid peptides on electrode covered with N-terminus-specific antibody based on electrocatalytic O2 reduction by Aβ(1-16)-heme-modified gold nanoparticles

Related studies

• Backgrounder on Nanoparticles and Amyloid Diseases (Kulinowski, Unknown year of publication).

• Reviewed studies regarding amyloid peptides in ex-vivo experimentations

• Blood and cerebral spinal fluid testing outside the body

• Nanoparticles bind to biomolecules to produce signals

• Inhibition or reduction of Amyloid protein fibril production with nanoparticles

http://icon.rice.edu/resources.cfm?doc_id=10866

• Electrochemical detection of β-amyloid peptides on electrode covered with N-terminus-specific antibody based on electrocatalytic O2 reduction by Aβ(1-16)-heme-modified gold nanoparticles (Liu, et al. 2013).

• Aβ(1-16)-heme-AuNPs detected Aβ testing it with cyclic voltammetry.

• About 10 pM of Aβ was the detection limit of the Aβ(1-16)-heme-AuNPs .

• Its results are comparable with the Surface Plasmon Resonance (incidence of light on electrons of the substrate).

• Problem:

• Does the sputtering procedure helps to spread a film of Tin oxide nanoparticles over a Siliciumsubstrate and a Carbon glass substrate?

• Hypothesis

• The sputtering procedure will deposit the Tin nanoparticles forming a film over an exposed area of the Silicium substrate and on the Carbon glass substrate.

Objectives:

• Demonstrate that the sputtering technique is an alternative for the development of thin film formations.

• Compare the final products in Silicium and Carbon glass substrates for differences.

• Help improve the affinity of Tin Oxide towards Amyloid Peptides by studying sputtering.

http://www.intechopen.com/source/html/10517/media/image1.jpg

Procedure

Prepare vacuum chamber

Magnetron Sputtering

SEM image

Procedure(Magnetron Sputtering)

Substrate(Anode)

Target(Cathode)

Argon Plasma(Ar+, Ar, e-, hυ)

Ar Ion

Sputtered particle4. Electrons released during Argon ionization are accelerated to the substrate, subsequently colliding with additional Argon atoms, creating more ions and free electrons in the process, continuing the cycle.

1. Electrically neutral Argon atoms are introduced into a vacuum chamber.

2. DC (direct current) voltage is placed between the target and substrate which ionizes Argon atoms and creates a plasma (glow discharge)

3. These Argon ions accelerate to the target. Their collision with the target ejects target atoms, which travel to the substrate and eventually settle.Ionized Argon bombards a target, releasing atoms which form layers on a substrate.

http://www.pfonline.com/articles/vacuum-deposition-processes

• Physical process • In a vacuum chamber,

gas pressure is less than the ambient atmospheric pressure.

First Result

• Si substrate

• 1 min.

• 50 W

• 160 ºC

• Bigger spheres due to high temperature and long period of exposure

Second Result

• SiOx substrate

• 20 s

• 50 W

• Room temperature (21-23ºC)

• Uneven nanoparticles because of low temperature.

Third Result

• Carbon glass substrate

• 10 s

• 50 W

• 150 ºC

• Circular shaped nanoparticles because of balanced adjustments of temperature and time exposure

Results in Comparison

• Si substrate

• 1 min.

• 50 W

• 160 ºC

• SiOx substrate

• 20 s

• 50 W

• Room temperature (21-23ºC)

• Carbon glass substrate

• 10 s

• 50 W

• 150 ºC

Conclusions

• The sputtering system is a versatile technique for depositing any solid material

• This procedure assures the deposition of Tin nanoparticles film over the exposed area of the Silicium substrate.

• Although the tested carbon glass substrate did not result as figured, it was understood that the error was due to maladjustments on temperature and time exposure.

Future Research

• Repeat the sputtering process on another glass Carbon substrate using another adjustments on temperature and exposure time.

• After obtaining a potential pure substrate product with the Tin oxide nanoparticle layer:

• The product would be sent to Dr. Ana Guadalupes’ group at UPR-Río Piedras for the testing part using Amyloid peptides.

• The electrochemical properties of the Amyloid peptides are studied doing cyclic voltammetry in relation to the Tin oxide nanoparticles and a Ferrocene connector.

Acknowledgments

• Dr. Wilfredo Otaño

• Mr. José Cruz

• RISE Program at UPR Cayey

• UPR Cayey

Tin Oxide Nanoparticles for Electrochemical Studies of Amyloid Peptides

A L E J A NDRA M. DE J E SUS SOTOK E NNY J . CO LO N CO LO NR ISE PR OG R AM