Chitosan thin films, elaborated by solvent casting, have been functionalized by incorporate nanoliposomes based on natural vegetable and marine lecithin. The physical-chemistry properties were characterized by water contact angle, swelling kinetic test, and Torsional Harmonic Atomic Force Microscopy analysis (TH–AFM). The surface wettability, swelling ratio, roughness and local stiffness of the chitosan thin films can be modifiedand controlled by adding of nanoliposomes. The water contact angle decreases from 75° (±2°) to 50° (±1°) and 38° (±1°) when the amount of soya and salmon nanoliposomes increased in chitosan films, respectively.At the same time, the films attain equilibrium state after seven daysin the presence of phosphate buffer saline. The surface topography of films are identical in terms of asymmetry and amplitude distribution of roughness measurements but showed a significant increase of asperity height when incorporating soya nanoliposomes. This variation induces a decrease of contact rigidity (0.6 Gpa) and of adhesive force value (11.7 nN). One of principal objective is to understand the underlying cell-matrix interactions. For this purpose human mesenchymal stem cells (hMSCs) were seeded on the films, the results of in vitro biocompatibility analysis showed that nanoliposomes/chitosan blend thin films are not toxic after 24 h cells seeding. The filmsfavour the cell adhesion and proliferation when the soya and salmon nanoliposomes concentration inferior to 2 mg/mL and 4 mg/mL, respectively. The salmon nanoliposomes/chitosan blend films especially showed a best cell proliferation in hMSCs culture with the concentration of 1 mg/mL. Nanoliposomes functionalized chitosan thin films on certain concentrations could offer ...
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...w surface energy like polymers. The Owens-Wendt theory divides the surface energy into two components: one due to dispersive interactions and one due to polar interactions 46. Owens and Wendt proved that the total surface energy of a solid, can be expressed as the sum of contributions from dispersive and polar force components. These can be determined from the contact angle, θ, data of polar and non-polar liquids with known dispersive and polar parts of their surface energy, via the following relations:
For these measurements, two liquids (water and diiodomethane) were used. The same Digidrop meter apparatus was used for surface energymeasurement of chitosan and blend films. The total surface energy, polar component and dispersion component of chitosan and nanoliposomes blend thin films before had been determined from the water and diiodomethane contact angle.
The cells unique nature has scientists intrigued to do research with the focus of finding a way that these cells can be used to replace patients’ injured or diseased tissues. Advancement is made to all the three types of stem cells namely embryonic stem cells, adult stem cells in addition to induced pluripotent cells. Embryonic cells are the building blocks of an embryo that is developing, and can develop into almost all body cell types. Somatic cells are found in the body tissues. They renew and regenerate in healthy bodies. The third type which is induced pluripotent is genetically modified embryo cells from skin cells.2 Research on these cells are geared towards saving humanity; a noble course.
...e materials at the nanoscale might include new form of nanobase toxicity. The individuals working with large quantity of nanomaterials need to take appropriate measures to avoid inhalation and ingestion. However, scientists have found silicon o be good for the construction of nanorobots because of its unique properties; durability, flexibility and conductivity. However, silicon cannot dissolve in body fluids. In addition, in medical applications biodegradability is going to be challenge due to the foreign particles inside the body and controlled mobility.
Antimicrobial encapsulated into polymeric nanoparticles is a suggested novel drug delivery system to treat CRS. Nanoparticles are categorized into nanospheres (matrix-like structure) and nanocapsules (vesicular systems). Nanospheres are a type of nanoparticles that allows drug encapsulation surrounded by a polymer matrix (Pinto Reis C. et al., 2006). Literature suggests Poly Lactic-co-Glycolic Acid (PLGA) is an attractive polymer to coat the nanospheres due to their biodegradable and biocompatible properties (Makadia HK. & Siegel SJ., 2011). The nanoprecipitation solvent-diffusion method was chosen for encapsulation of the poorly water-soluble drug MUP. Initially, an oil-in-water emulsion is formed. PLGA and MUP in a 1:1...
Molecules attract one another’s opposite partial pole due to London dispersion and Coulomb force. Substances in a mixture are not chemically bonded. There are four types of intermolecular bonds with ethanol which are London dispersion, dipole-dipole, covalent, and hydrogen. Ethanol will interact with water and bond producing a tightly bonded mixture, where as vegetable oil does not mix with water molecules. Theses structures are depicted in the figure below:
In a phenomenon termed the “hydrophobic effect”, 4 surfactants act the way they do in
Stem Cells: What, How and Why? Stem cells are infinitely valuable when considering their potential applications in the medical profession. While current legislative restrictions have halted the development of new ?stem cell lines? to any agency or company that receives any form of governmental grants, there is no question that the medical profession is standing at the brink of a new era of technological advancements in healthcare and research.
In this case study, our concern goes for the chitosan nanoparticles; firstly nanoparticles are able to adsorb and/or encapsulate a drug, thus protecting it against chemical and enzymatic degradation. Furthermore the encapsulated drug may be prevented from crystallization, thus forming a solid solution. Depending on drug solubility in the carrier, a drug load varying from only a few percent up to 50%] Secondly, chitosan is ...
Stem cell research can date back to 1956 and has lead to multiple medical breakthroughs. Stem cells are generic animal cells that can make copies of themselves indefinitely. Therefore, these cells have to ability to become any body part or organ (Cowan). But, getting this resource is what brings up a controversy. Scientists and researchers are gathering human embryos to further study and test stem cells and some people don’t agree with this. The end result of using embryonic stem cells is someone being able to walk again, someone remembering the names of their children, and someone being able to say that he beat cancer. Stem cell research is beneficial to society and should be accepted into labs all around the world.
Whereas there are many facets of medical research in the world at the present time, one of the more controversial continues to be stem cell research and more specifically, embryonic stem cell research. The percentage of groups and individuals who agree or disagree with this science are roughly equal on both sides of the argument. There are many quarrels within this one area including “should stem cell research be federally funded”, “is embryonic stem cell research ethical”, and “is the outcome of stem cell research worth it”? While there is no right or wrong answer to these questions, since the answer would vary depending on whom you ask, the argument regarding this topic remains quite passionate and heated.
Stem cell research is one of the most widely expanding areas of scientific research being conducted all over the world today. In basic terms, stem cell research is the research of stem cells; however in actuality is much more complicated. A stem cell is a cell with the ability to develop into any of the cell types that make up the tissues and organs of the body. This makes these cells highly useful and provides endless opportunities in the field of regenerative medicine.
The objective of this experiment was to investigate the relationship of dispersion forces and hydrogen bonding forces in intermolecular attractions through the evaporation of different substances. Using temperature probes, the endothermic process of evaporation is measured by inserting the probes into the substance and then taking them out to allow the substance to evaporate, the change in temperature of the substances showed if a lot or not a lot of evaporation occurred and over how long the evaporation took place depending on if the change in temperature was high or low.
What if there was a cure for cancer or a treatment for spinal injuries? Would you support the research? What if there was a way that you could repair damaged nerves. Some believe that stem cells may hold the answers to some of these questions. What are stem cells and why should you or I even care about them? Some believe that they are a miracle treatment waiting to happen while others believe that stem cells are highly immoral. Why does so much controversy surround the issue? Why is the conversation of stem cells feared by some and praised by others? To some stem cells are the medical hopes for the future, something for us to hang on to as we do battle with major diseases that include cancer, Parkston’s disease and spinal injuries. To others stem cell researchers are murderers who are trying to play God’s hand. A many have pledged their support to stem cell research including a few well known celebrities. Reeves’, who was best known for his role in the early Superman movies, and J. Fox two well-known celebrities, have pledged to stem cell research, both have created a private fund for the research of stem cells. This celebrity however has not swayed everyone to support stem cell researches cause. Just as there are supporters of stem cells there are those who believe that the use of stem cells is immoral. Since the first stem cells were separated there have been doctors, religious groups and even some political figure head have shown their opposition for stem cell research. Even with the knowledge and promise that stem cells show many of those who truly oppose stem cells have not changed their mind. The question is are their reasons good enough to halt the research of stem cell or are they just holding back what will soon be inevi...
The new technology uses water-repellent ferrous nanoparticles. Once these particles are combined in with the oil, they join to the oil an...
Alford, Terry L., L. C. Feldman, and James W. Mayer. Fundamentals of Nanoscale Film Analysis. New York: Springer, 2007. Print.
Ionic compounds, when in the solid state, can be described as ionic lattices whose shapes are dictated by the need to place oppositely charged ions close to each other and similarly charged ions as far apart as possible. Though there is some structural diversity in ionic compounds, covalent compounds present us with a world of structural possibilities. From simple linear molecules like H2 to complex chains of atoms like butane (CH3CH2CH2CH3), covalent molecules can take on many shapes. To help decide which shape a polyatomic molecule might prefer we will use Valence Shell Electron Pair Repulsion theory (VSEPR). VSEPR states that electrons like to stay as far away from one another as possible to provide the lowest energy (i.e. most stable) structure for any bonding arrangement. In this way, VSEPR is a powerful tool for predicting the geometries of covalent molecules.