Silica vs. PS NP etching rates
Published on: Mar 3, 2016
Transcripts - Silica vs. PS NP etching rates
Qualitative Analysis: SiO2
and Polystyrene NP Etching
Using Lactic Acid
Ann Meek | Sarin Parikh |Suranjan Oruganti
Negin M., Yasan Y., and Mukanth V.
II. Objective and Background
were part of the
body and shouldn’t
To the left: A peptide “passport” attached to nanoparticles
tells macrophages “Don’t eat me” (credit:: Mary Leonard,
Biomedical Art & Design)
To engineer quasi-
molecular complexes for
highly specialized delivery,
it is essential to understand
endocytosis (right): the
mechanism by which a cell
internalizes a vesicle from
Melis Çağdaş, Ali Demir Sezer and Seyda Bucak (2014). Liposomes as Potential Drug
Carrier Systems for Drug Delivery, Application of Nanotechnology in Drug Delivery, PhD.
Ali Demir Sezer (Ed.),
The goal of this experiment is to qualitatively assess the etching
characteristics of a nanoparticle in an endosomal
Why Silica & Lactic Acid?
• The material must be versatile in its surface functionality, size-
modulation and porosity. Biological-relevant functionality include:
favoring colloidal stability, long-time blood circulation. The evaluation of
silica-based nanoparticles as drug carriers has become very popular
among the last 5 years or so (Slowing et al. 2008; Di Pasqua et al. 2008;
Rosenholm et al. 2010).
• Late endosomes contain lactic acid of pH 4.5-5.5 and could melt away the
thin silica shell.
Effects of nanoparticles on the body
Flow-chart to the left:
Simone Morais and
Maria do Carmo
Their Impacts on
Public Health, Current
Topics in Public
Health, Dr. Alfonso
I. Coating with TMOS and APTMS
IV. Sealing with PLL
I. Coating withTMOS and APTMS
• Polystyrene beads were mixed with 2 samples of
ethanol, APTMS and TMOS were mixed in a solution
with the beads and sonicated.
11Jung, Hak-Sung, Doo-Sik Moon, and Jin-Kyu Lee. "Quantitative Analysis and Efficient Surface Modification of Silica Nanoparticles." Journal of Nanomaterials 2012 (2012): 1-8. Web.
• The samples were washed using ethanol
• Centrifuged at 4000 RPM, 20 °C for 10 min
• Extra liquid was pipetted out
• Sample particles mixed with ethanol
• Placed on 4 glass slides for 12 hours
at 480 °C
• Slide washed once with ethanol and
3x with water and emptied into
• 3 solutions created with lactic acid
at pH 2.1, 4.5, 6.9.
Before & After Calcination
Réfega, Ricardo. "Nanoparticles in Biomedical Imaging." Fundamental Biomedical Technologies (2008): Web.
IV. Seal with PLL
• Silicic acid added to PLL to
seal particles overnight.
SEM of Nanoparticles
• 26 solutions were created using a lactic acid
solution and 37°C bath
Each sample placed on
siliconwafer for analysis under
Results Calcinated at pH 4.5
10 min 1 hr
6 hr Overnight
Results Non-Calcinated at pH 4.5
6 hr Overnight
Results Calcinated at pH 2.1
Results Non-Calcinated at pH 2.1
Results Calcinated at pH 6.9
Results Non-Calcinated at pH 6.9
● PLL protected the silica!
● From our results, we gathered that the PLL barrier prevented
the silica from etching.
Room For Improvment
- Washing: the etching is pH sensitive.
- Use Dye as maker: For noncalcinated particles we can use
fluorescent dye in the NP that are released upon rupture.
Then use UV-Vis.
- Preventing colloidal aggregation
Sources of Error
- TMOS and APTMS added in separate vials
- Image J was used for analysis
● It must be noted that agglomerate forms of nanoparticles
might interact differently in a system than in single form.
● To keep the nanoparticles in monodispersed suspension,
coatings must be applied
● PLL can be used as a protector from etchants
● Longer circulating pattern for NP coated with PLL and PEG
- Dr. Esener,
- (Dr. Tao, Dr. Sirbuly, Dr. Luo, Dr. Horvath).
- Negin M., Yasan Y., and Mukanth V.
- Thank you audience for listening