Page 89 - ASME_NEMB_2016_Program

TRACK 6 TRACK 6 Technical Program

The needles are inductively heated by an alternating magnetic field and Open cell porous media can be envisioned as a collection of randomly inter-
their tips are deflected by a constant magnetic field. Cell viability studies of connected struts. The properties, both the geometrical (cross- sectional area
HCT 116 (human colorectal carcinoma) cells grown on substrates with the iron and length) and the mechanical (Young’s modulus, Poisson ratio, fracture
nano needles was analyzed via Calcein AM / Ethidium homodimer-1 fluores- ) ones of the struts may exhibit significant variations from cell to cell, even
cent staining, revealing a high degree of biocompatibility for up to 24 hours within a cell. The complexity of the structure of the open cell porous media
of incubation. Fluorescence and confocal microscopy analysis showed the poses difficulty for modelling their mechanical behavior. Finite Element Anal-
growth of cells on top of the needles, with the restructuring of the cell mem- ysis (FEA) has been proven to be useful to model the mechanical behavior
brane around the needles. These properties make arrays of such magnetic of open cell porous media. Li et al. [1] studied the mechanical response of
nano needles on cell culture substrates promising tools for cell analysis. an open cell porous medium with various cell size and strut cross sectional
area. Another approach for modelling the mechanical behavior of porous
medium is to replace it with an equivalent continuum for which Gibson and
The effect of surface corona on the interaction of silver nanopar- Ashby [2] can be referred to.
ticles with human serum and on toxicity to cancer cells
A homogenization method for modelling mechanical behavior of cancellous
bone employing the theory of elastic mixtures is introduced. A short survey
Poster Presentation. NEMB2016-5978 on cancellous bones and importance of its mechanical behavior is provided.
The models available in the literature for the mechanical behavior of cancel-
Amanda N Abraham, Vipul Bansal, Ravi Shukla, RMIT University, lous bones are summarized. The scheme for modelling the solid skeleton of
Melbourne, VIC,Australia cancellous bone is introduced in full detail. Wave propagation in cancellous
bone is studied and it is shown that the constitutive equation obtained in the
Silver nanoparticles (AgNPs) incur the highest incorporation in consumer study is capable to represent positive and negative dispersion as well as
and medical products to date, due to their broad spectrum antibacterial and attenuation. The effect of bone marrow on wave propagation is discussed
antifungal properties. They are widely used in catheters, wound dressings by incorporating a generalized Biot’s theory. This study is concluded by
and various household products such as electronics, cosmetics, tooth- indicating that the quantitative ultrasound can be extended to obtain some
pastes, shampoos, air sanitiser sprays, bedding, clothing etc. Typically, silver estimation about the micro-architectural parameters of cancellous bone.
nanoparticles are synthesized using a reducing agent and a stabilising
agent, such as hydrazine and sodium borohydride. However, both these and REFERENCES
many other reducing and stabilising agents used in nanoparticle synthesis [1] Li, K., X. L. Gao, et al.. “Effects of Cell Shape and Strut Cross-Sectional
are highly toxic to living organisms and the environment. Area Variations on the Elastic Properties of Three-Dimensional Open-Cell
Foams”, Journal of the Mechanics and Physics of Solids, 54(4): 783-806,
One alternative method of AgNP synthesis involves the use of plant extracts 2006.
such as Aloe vera, cinnamon, edible mushrooms and neem. Evidence sug- [2] Gibson, L. J., M. F. Ashby Cellular Solids: Structure and Properties, Cam-
gests that the polyphenol compounds present in these plant extracts are bridge University Press, 1999.
responsible for the reduction of the metal ions to nanoparticles while simul-
taneously coating the surface of the nanoparticles. In order to extend the
usage of these AgNPs for biological applications, the mechanism of action Dense iron nanowire array for the culture and regulation of fate
needs to be fully understood. Currently, it is not known whether the effect of mesenchymal stem cells
on cells is elicited due to the polyphenolic coating (surface corona) or due to
the core of the nanoparticle. Another aspect to keep in mind when consid-
ering the use of NPs for in vivo purposes is that NPs interact with biological Poster Presentation. NEMB2016-5945
fluids such as a serum before reaching the target organ. However, it is un-
known what role the surface corona plays in interaction with proteins found Jose Perez, King Abdullah University of Science and Technology,
in the blood or in cell culture media in in vivo and in vitro scenarios. Thuwal, Makkah,Saudi Arabia, Timothy Ravasi, Jurgen kosel, King
Abdullah University of Science & Technology, Thuwal, Select State/
In order to shed some light on these aspects, this study used silver nanopar- Province,Saudi Arabia
ticles (AgNPs) synthesised with bi-and polyphenolic compounds viz. curcum-
in from turmeric and Epigallocatechin gallate (EGCG) from green tea, respec- Mesenchymal stem cells are highly sensitive to mechanical stimuli, respond-
tively. L-Tyrosine, a monophenolic amino acid was used as a control as it is ing with the regulation of fate through the reorganization of the cytoskeleton
an amino acid found in all living organisms and is not toxic to the body. The and activation of specific signaling pathways. In this work, an array of iron
interaction of these AgNPs with human serum albumin (HSA) was elucidated nanowires was studied for its use as a substrate for the culture and mechan-
using fluorescence spectroscopy and toxicity to prostate cancer (PC-3) cells ical stimulation of mesenchymal stem cells. For this purpose, a nanoporous
was analysed using trypan blue dye exclusion assay and confocal micros- alumina template was fabricated by a two-step anodization process, fol-
copy. The results suggest that while the surface corona does dictate the lowed by a pulsed electrodeposition step of iron in the array of pores. Then,
interaction with serum and toxicity, the effect on toxicity appears to be a syn- a partial release of the template was performed via wet chemical etching in
ergistic effect of both the surface corona and the silver core of the AgNPs. order to remove a portion of the nanoporous alumina and reveal an array of
dense, vertically aligned nanowires. In order to study cell growth, attachment
and spreading behavior on the nanowire array, human mesenchymal stem
Modelling Cancellous Bone: An Elastic Mixture Theory Approach cells were cultured for up to six days and then fluorescently stained for actin
filaments and cell nuclei. Fluorescence staining of cells with Calcein AM and
Poster Presentation. NEMB2016-5903 Ethidium homodimer-1 allowed the determination of cell viability at differ-
ent incubation times. Additionally, the interface between the cells and the
Burhanettin Altan, Giresun UNiversity, Giresun,Turkey nanowire array was observed by scanning electron microscopy after critical
point drying. Results showed a reorganization of actin filaments coupled to
an altered, spherical cell shape. Actin filaments accumulated in bundles at
Bones are common in all mammals as well as in birds and other animals the adhesion points of the cells on the nanowires, driving the change of cell
which are typical examples of open cell porous media that can be found in shape. The cell viability of attached cells remained higher than 90% up to six
the nature as light-weight structural elements. Man-made open cell porous days of incubation, though the overall number of attached cells was lower
media are also used as materials for light-weight structural elements with compared to the control. The interface between the cells and the nanowire
high specific strengths as well as thermal insulators. It is an ongoing ac- array confirmed the reorganization of actin and showed the focal adhesion 89
tive research field to develop methods to predict the mechanical, thermal, points on the iron nanowire array. The cells possess sufficient force to pull
acoustical behavior of open cell porous media. the nanowires towards themselves as they alter their shape. Further, multiple