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Volume 7, Issue 2 (Suppl) J Biotechnol Biomater
ISSN: 2155-952X JBTBM, an open access journal Biomaterials 2017
March 27-28, 2017
2nd Annual Conference and Expo on
March 27-28, 2017 Madrid, Spain
J Biotechnol Biomater 2017, 7:2 (Suppl)
Parametric designs based on CFD for a new generation of ventricular catheters for hydrocephalus
Marcelo Galarza, Angel Giménez and José María Amigó
Hospital Universitario Virgen de la Arrixaca, Spain
Background: To drain the excess of cerebrospinal fluid in a hydrocephalus patient, a catheter is inserted in one of the brain ventricles,
and then connected to a valve. This so-called ventricular catheter is a standard-size, flexible tubing with a number of holes placed
symmetrically around several transversal sections or “drainage segments”. Three-dimensional computational dynamics shows that
most of the fluid volume flows through the drainage segment closest to the valve. This fact raises the likelihood that those holes and
then the lumen get clogged by the cells and macromolecules present in the cerebrospinal fluid, provoking malfunction of the whole
system.
Objective:To better understand the flow pattern, we have carried out a parametric study via numerical models of ventricular catheters.
Methods: The parameters chosen are the number of drainage segments, the distances between them, the number and diameter of the
holes on each segment, as well as their relative angular position.
Results: These parameters were found to have a direct consequence on the flow distribution and shear stress of the catheter. As a
consequence, we formulate general principles for ventricular catheter design. To exclude the drainage area of the segments from the
set of parameters, the drainage areas of the distal segment, and the proximal segment, were conveniently chosen in each group, while
the drainage areas of the remaining segments.
Conclusions: These principles can help develop new catheters with homogeneous flow patterns thus possibly extending their lifetime.
Characterizationof biomaterialsusingAFMbased fast nanoscale imagingandquantitativenanomechanical
techniques
T Neumann, T Müller, D Stamov, H Haschke, C Pettersson, S Kostrowski and T Jähnke
JPK Instruments AG, Germany
Besides structural and physico-chemical composition, topography, roughness, adhesiveness as well as mechanical properties of
biomaterials are the relevant factors making them suitable for biomedical applications. All these factors affect cell differentiation
and tissue formation, and are crucial for their integration as well as healing capacity in the human body. Atomic Force Microscopy is
suitable for measuring all of these characteristics with nanometer scale resolution under physiological conditions. We have developed
a multipurpose AFM device allowing comprehensive characterization of biological samples such as live cells, tissues and biomaterials
in the nanoscale. True optical integration allows the simultaneous use of advanced inverted optical microscope techniques such as
DIC or confocal laser scanning microscopy, but also upright optics, such as macroscopes for the investigation of opaque samples.
With our “Quantitative Imaging” (QI™) mode several sample properties, such as the topography, stiffness and adhesiveness, can
be obtained with one measurement in high resolution. Even more complex data like Young´s modulus images, topography at
different indentation forces in terms of tomography, or recognition events can be obtained. A variety of biological samples have
been investigated to demonstrate the capability and flexibility of QI™. The NanoWizard® ULTRA Speed technique allows fast AFM
imaging of dynamic processes with approximately 1 frame per second. The kinetics of collagen type I fibrillogenesis was imaged in
situ with high spatiotemporal resolution, revealing the formation of the 67 nm D-banding hallmark. With the CellHesion® technique,
the adhesion of a single living cell to any substrate can be measured and validated using comprehensive analysis tools. The side-view
cantilever holder enables a side view of the cell-sample interface while performing adhesion experiments, providing complementary
information without expensive z-stacking. The inherent drawbacks of traditional AFM imaging modes for fast imaging or for
challenging samples like living cells can be overcome by the NanoWizard® ULTRA Speed and QI™ mode. We present an enhancement
of the AFM technique providing a versatile tool for an extensive characterization of biomaterials.