Abstract: Biometallic materials are the most important materials for use in biomedical applications especially in manufacturing a variety of biological artificial replacements in a modern worlds, e.g. hip, knee or shoulder joints, due to their advanced characteristics. Titanium (Ti) and its alloys are used extensively in biomedical applications based on their high specific strength and excellent corrosion resistance. Beta-Ti alloys containing completely biocompatible elements are exceptionally prospective materials for manufacturing of bioimplants. They have superior mechanical, chemical and electrochemical properties for use as biomaterials. These biomaterials have the ability to introduce the most important property of biochemical compatibility which is low elastic modulus. This review examines current information on the recent developments in alloying elements leading to improvements of beta Ti alloys for use as biomaterials. Moreover, this paper focuses mainly on the evolution, evaluation and development of the modulus of elasticity as an effective factor on the performance of beta alloys.
Abstract: A major challenge in biomaterials research is the
regulation of protein adsorption which is a key factor for controlling
the subsequent cell adhesion at implant surfaces. The aim of the
present study was to control the adsorption of fibronectin (FN) and
the attachment of MG-63 osteoblasts with an electronic
nanostructure. Shallow doping line lattices with a period of 260 nm
were produced for this purpose by implantation of phosphorous in
silicon wafers. Protein coverage was determined after incubating the
substrate with FN by means of an immunostaining procedure and the
measurement of the fluorescence intensity with a TECAN analyzer.
We observed an increased amount of adsorbed FN on the
nanostructure compared to control substrates. MG-63 osteoblasts
were cultivated for 24h on FN-incubated substrates and their
morphology was assessed by SEM. Preferred orientation and
elongation of the cells in direction of the doping lattice lines was
observed on FN-coated nanostructures.
Abstract: Antimicrobial (AM) starch-based films were
developed by incorporating chitosan and lauric acid as antimicrobial
agent into starch-based film. Chitosan has wide range of applications
as a biomaterial, but barriers still exist to its broader use due to its
physical and chemical limitations. In this work, a series of
starch/chitosan (SC) blend films containing 8% of lauric acid was
prepared by casting method. The structure of the film was
characterized by Fourier transform infrared spectroscopy (FTIR), Xray
diffraction (XRD), and scanning electron microscopy (SEM).
The results indicated that there were strong interactions were present
between the hydroxyl groups of starch and the amino groups of
chitosan resulting in a good miscibility between starch and chitosan
in the blend films. Physical properties and optical properties of the
AM starch-based film were evaluated. The AM starch-based films
incorporated with chitosan and lauric acid showed an improvement in
water vapour transmission rate (WVTR) and addition of starch
content provided more transparent films while the yellowness of the
film attributed to the higher chitosan content. The improvement in
water barrier properties was mainly attributed to the hydrophobicity
of lauric acid and optimum chitosan or starch content. AM starch
based film also showed excellent oxygen barrier. Obtaining films
with good oxygen permeability would be an indication of the
potential use of these antimicrobial packaging as a natural packaging
and an alternative packaging to the synthetic polymer to protect food
from oxidation reactions
Abstract: Scaffolds play a key role in tissue engineering and can be produced in many different ways depending on the applications and the materials used. Most researchers used an experimental trialand- error approach into new biomaterials but computer simulation applied to tissue engineering can offer a more exhaustive approach to test and screen out biomaterials. This paper develops the model of scaffolds and Computational Fluid Dynamics that show the value of computer simulations in determining the influence of the geometrical scaffold parameter porosity, pore size and shape on the permeability of scaffolds, magnitude of velocity, drop pressure, shear stress distribution and level and the proper design of the geometry of the scaffold. This creates a need for more advanced studies that include aspects of dynamic conditions of a micro fluid passing through the scaffold were characterized for tissue engineering applications and differentiation of tissues within scaffolds.
Abstract: The field of polymeric biomaterials is very important
from the socio-economical viewpoint. Synthetic carbohydrate
polymers are being increasingly investigated as biodegradable,
biocompatible and biorenewable materials. The aim of this study was
to synthesize and characterize some derivatives based on D-mannose.
D-mannose was chemically modified to obtain 1-O-allyl-2,3:5,6-di-
O-isopropylidene-D-mannofuranose and 1-O-(2-,3--epoxy-propyl)-
2,3:5,6-di-O-isopropylidene-D-mannofuranose.
The chemical structure of the resulting compounds was
characterized by FT-IR and NMR spectroscopy, and by HPLC-MS.
Abstract: Magnesium alloy has been widely investigated as
biodegradable cardiovascular stent and bone implant. Its application
for biodegradable esophageal stenting remains unexplored. This
paper reports the biodegradation behaviors of AZ31 magnesium alloy
in artificial saliva and various types of beverage in vitro. Results
show that the magnesium ion release rate of AZ31 in artificial saliva
for a stent (2cm diameter, 10cm length at 50% stent surface
coverage) is 43 times lower than the daily allowance of human body
magnesium intakes. The degradation rates of AZ31 in different
beverages could also be significantly different. These results suggest
that the esophagus in nature is a less aggressive chemical
environment for degradation of magnesium alloys. The significant
difference in degradation rates of AZ31 in different beverages opens
new opportunities for development of degradation controllable
esophageal stent through customizing ingested beverages.
Abstract: Hair is a non homogenous complex material which
can be associated with a polymer. It is made up 95% of Keratin.
Hair has a great social significance for human beings. In the High
Middle Ages, for example, long hairs have been reserved for kings
and nobles.
Most common interest in hair is focused on hair growth, hair types
and hair care, but hair is also an important biomaterial which can
vary depending on ethnic origin or on age, hair colour for example
can be a sign of ethnic ancestry or age (dark hair for Asiatic, blond
hair for Caucasian and white hair for old people in general).
In this context, different approaches have been conducted to
determine the differences in mechanical properties and characterize
the fracture topography at the surface of hair depending on its type
and its age.
A tensile testing machine was especially designed to achieve
tensile tests on hair. This device is composed of a microdisplacement
system and a force sensor whose peak load is limited to
3N. The curves and the values extracted from each experiment, allow
us to compare the evolution of the mechanical properties from one
hair to another.
Observations with a Scanning Electron Microscope (SEM) and
with an interferometer were made on different hairs. Thus, it is
possible to access the cuticle state and the fracture topography for
each category.
Abstract: The importance for manipulating an incorporated
scaffold and directing cell behaviors is well appreciated for tissue
engineering. Here, we developed newly nano-topographic oxidized
silicon nanosponges capable of being various chemical modifications
to provide much insight into the fundamental biology of how cells
interact with their surrounding environment in vitro. A wet etching
technique is exerted to allow us fabricated the silicon nanosponges in a
high-throughput manner. Furthermore, various organo-silane
chemicals enabled self-assembled on the surfaces by vapor deposition.
We have found that Chinese hamster ovary (CHO) cells displayed
certain distinguishable morphogenesis, adherent responses, and
biochemical properties while cultured on these chemical modified
nano-topographic structures in compared with the planar oxidized
silicon counterparts, indicating that cell behaviors can be influenced
by certain physical characteristic derived from nano-topography in
addition to the hydrophobicity of contact surfaces crucial for cell
adhesion and spreading. Of particular, there were predominant
nano-actin punches and slender protrusions formed while cells were
cultured on the nano-topographic structures. This study shed potential
applications of these nano-topographic biomaterials for controlling
cell development in tissue engineering or basic cell biology research.
Abstract: Identifying the nature of protein-nanoparticle
interactions and favored binding sites is an important issue in
functional characterization of biomolecules and their physiological
responses. Herein, interaction of silver nanoparticles with lysozyme
as a model protein has been monitored via fluorescence spectroscopy.
Formation of complex between the biomolecule and silver
nanoparticles (AgNPs) induced a steady state reduction in the
fluorescence intensity of protein at different concentrations of
nanoparticles. Tryptophan fluorescence quenching spectra suggested
that silver nanoparticles act as a foreign quencher, approaching the
protein via this residue. Analysis of the Stern-Volmer plot showed
quenching constant of 3.73 μM−1. Moreover, a single binding site in
lysozyme is suggested to play role during interaction with AgNPs,
having low affinity of binding compared to gold nanoparticles.
Unfolding studies of lysozyme showed that complex of lysozyme-
AgNPs has not undergone structural perturbations compared to the
bare protein. Results of this effort will pave the way for utilization of
sensitive spectroscopic techniques for rational design of
nanobiomaterials in biomedical applications.
Abstract: In this study, stress distributions on dental implants
made of functionally graded biomaterials (FGBM) are investigated
numerically. The implant body is considered to be subjected to axial
compression loads. Numerical problem is assumed to be 2D, and
ANSYS commercial software is used for the analysis. The cross
section of the implant thread varies as varying the height (H) and the
width (t) of the thread. According to thread dimensions of implant
and material properties of FGBM, equivalent stress distribution on
the implant is determined and presented with contour plots along
with the maximum equivalent stress values. As a result, with
increasing material gradient parameter (n), the equivalent stress
decreases, but the minimum stress distribution increases. Maximum
stress values decrease with decreasing implant radius (r). Maximum
von Mises stresses increases with decreasing H when t is constant.
On the other hand, the stress values are not affected by variation of t
in the case of H = constant.
Abstract: This paper aims at overviewing the topics of a research project (CARDIOSENSOR) on the field of health sciences (biomaterials and biomedical engineering). The project has focused on the development of a nanosensor for the assessment of the risk of cardiovascular diseases by the monitoring of C-reactive protein (CRP), which has been currently considered as the best validated inflammatory biomarker associated to cardiovascular diseases. The project involves tasks such as: 1) the development of sensor devices based on field effect transistors (FET): assembly, optimization and validation; 2) application of sensors to the detection of CRP in standard solutions and comparison with enzyme-linked immunosorbent assay (ELISA); and 3) application of sensors to real samples such as blood and saliva and evaluation of their ability to predict the risk of cardiovascular disease.
Abstract: The field of biomedical materials plays an imperative
requisite and a critical role in manufacturing a variety of biological
artificial replacements in a modern world. Recently, titanium (Ti)
materials are being used as biomaterials because of their superior
corrosion resistance and tremendous specific strength, free- allergic
problems and the greatest biocompatibility compared to other
competing biomaterials such as stainless steel, Co-Cr alloys,
ceramics, polymers, and composite materials. However, regardless of
these excellent performance properties, Implantable Ti materials have
poor shear strength and wear resistance which limited their
applications as biomaterials. Even though the wear properties of Ti
alloys has revealed some improvements, the crucial effectiveness of
biomedical Ti alloys as wear components requires a comprehensive
deep understanding of the wear reasons, mechanisms, and techniques
that can be used to improve wear behavior. This review examines
current information on the effect of thermal and thermomechanical
processing of implantable Ti materials on the long-term prosthetic
requirement which related with wear behavior. This paper focuses
mainly on the evolution, evaluation and development of effective
microstructural features that can improve wear properties of bio
grade Ti materials using thermal and thermomechanical treatments.
Abstract: In this study, the powders of Ni and Ti with 50.5 at.%
Ni for 12 h were blended and cold pressed at the different pressures
(50, 75 and100 MPa).The porous product obtained after Ni-Ti
compacts were synthesized by SHS (self-propagating hightemperature
synthesis) in the different preheating temperatures (200,
250 and 300oC) and heating rates (30, 60 and 90oC/min). The effects
of the pressure, preheating temperature and heating rate were
investigated on biocompatibility in vivo. The porosity in the
synthesized products was in the range of 50.7–59.7 vol. %. The
pressure, preheating temperature and heating rate were found to have
an important effect on the biocompatibility in-vivo of the synthesized
products. Max. fibrotic tissue within the porous implant was found in
vivo periods (6 months), in which compacting pressure 100MPa.
Abstract: This paper aims at presenting the biotechnology used
to obtain collagen-based gels from shark (Squalus acanthias) and brill
skin, marine fish growing in the Black Sea. Due to the structure of its
micro-fibres, collagen can be considered a nanomaterial; in order to
use collagen-based matrixes as biomaterial, rheological studies must
be performed first, to state whether they are stable or not. For the
triple-helix structure to remain stable within these gels at room or
human body temperature, they must be stabilized by reticulation.