February 2007
Chitosan nanoparticles - a biocompatible and efficient nano delivery system
Introduction
Medical researchers work at the nano and micro scales to develop new drug delivery methods, for novel therapeutics and pharmaceuticals. Nanotechnology in drug delivery is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable efficient drug/gene delivery applications. They show no or tolerable levels of toxicity/side effects and a drug with high potency can easily be administered through these nanodelivery systems desired low quantity. This is definitely an advantage over treatments involving chemotherapy and high radiations, where after sometime the treatment has to be stopped due to its adverse side effects. Even after the drug has successfully been administered into the system, studies like biodistribution, pharmacokinetics and toxicity analysis only determines the safe and an efficient on-target delivery. Meticulous research and advancements in drug discovery has opened many new vistas in therapeutic strategies like treating cancers, immunological and neurological disorders but has not been able to stop genetic diseases.
As a way out to this, a new dimension in oligonucleotide therapy called sequence specific siRNA mediated gene silencing has evolved, which emphasize on suppressing the expression of the diseased gene at the mRNA level. However, efficient, safe and specific delivery of novel therapeutics remains an important bottleneck for the development and standardization of sequence specific gene silencing siRNA therapeutic strategy. Although, substantial development has been made in the chitosan based nanocarriers in the delivery of novel therapeutics like gene/siRNA/oligonucleotide therapy, small molecular pharmacophores and small peptide drugs, the therapeutic potential of these particles in the clinical arena and long term human responses remain to be evaluated. Studies based on nanoparticle mediated gene delivery mechanisms are trying to bridge the gap between the in-vitro analyses to optimize the in-vivo delivery conditions. Many natural and synthetic polycations, which are biocompatible and biodegradable have been employed as possible delivery systems for novel therapeutic molecules. The naturally occurring delivery vectors include proteins such as histones [Balicki et al., 2000; Esser et al., 2000] and cationized human serum albumin [Fischer, 2001], as well as aminopolysaccharides such as chitosan [Mumper et al., 1995; Borchard, 2001].
Authors:Meenakshi Malhotra,V. R. Swamy.
DNA Nanotechnology
Introduction
DNA is more than just the secret of life-it is also a versatile component for making nanoscopic structures and devices. Today thousands of researchers are hard at work deciphering the myriad ways that genes control the development and functioning of organisms. All those genes are written in the medium that is DNA. Molecular self-assembly offers a means of spontaneously forming complex and well-defined structures from simple components. The specific bonding between DNA base pairs has been used in this way to create DNA-based nanostructures and to direct the assembly of material on the sub-nanometric to micrometer scale. By employing the techniques of modern biotechnology, we can make long DNA molecules with a sequence of building blocks chosen at will. That ability opens the door to new paths not taken by nature when life evolved. Thus DNA can be used for building of structures and devices whose essential elements and mechanisms range from around 1 to 100 nanometers in size-in a word, nanotechnology.
DNA
The nanoscale is the scale of molecules. A typical bond between two atoms is about 0.15 nanometer long (A nanometer is a billionth of a meter). DNA is a nanoscale structure, consisting of a double backbone of phosphate and sugar molecules between which complementary pairs of bases (A and T; C and G) are connected by weak bonds. DNA's most common conformation is B-DNA, which twists in a right-handed double helix about two nanometers in diameter. One full turn of the helix is about 3.5 nanometers, or 10 to 10.5 base pairs long. In special circumstances DNA can form a left-handed double helix called Z-DNA. A short piece of DNA has highly specific interactions with other chemicals, depending on its sequence of base pairs. One can imagine using such pieces to recognize particular molecules or to control the composition of a material by acting as a catalyst. And for many years biologists have used DNA for its recognition properties, especially exploiting the “sticky ends” in genetic engineering. A sticky end occurs when one strand of the helix extends for several unpaired bases beyond the other. The stickiness is the propensity of the overhanging piece to bond with a matching strand that has the complementary bases in the corresponding order. The base adenine on one-strand pairs with thymine on the opposite strand, and cytosine binds with guanine. At first sight, it does not appear that DNA can lead to interesting structures. Naturally occurring DNA forms a linear chain, like a long piece of twine, so that all one can envision making from it is lines or circles, perhaps snarled up or knotted in one way or another. But a linear chain is not the only form that DNA takes.
Authors: A.KOTEESWARAN, M.MOHAN.
Nanomedicine
The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big. - Richard Feynman.
Introduction
As humans we have always been enchanted by the effect of huge things and believed in the potential of colossal objects almost blindly evidenced by the extra large plasma television or a large mansion. If we think small things are of no importance, it would be a big blunder as even a single dot is made of much smaller particles. Thus, it would not be wrong to think that usage of these minute things can lead to introduction of great comfort in our life. This vision of minute particles influencing our lives can be dated back, conclusively, to the year 1959 when Richard P. Feynmann presented a talk “There's Plenty of Room at the Bottom” at the annual meeting of the American Physical Society. Later in 1966 Isaac Asimov also wrote about these little things in his book Fantastic Voyage. Both of them had proposed small invisible machines that could work to influence human life. Thus, was born a branch of science called nanotechnology. The word 'Nanotechnology' is derived from two words: 'nanos' (Greek: dwarf) + technology. It is the study of objects of order of 100 nanometers or less, where a nanometer is one billionth of a meter (Figure 1). So, nanotechnology caters to the study of objects that are invisible to the eye and as small in dimensions as molecules in the body. This study is important for us as the particles, when in the range of nanometers, show properties quite different from what we observe in our daily life. A good example of this is gold, which shows a change in color, and melting point when studied at nanometer stage. When nanotechnology was applied to human system for studying its working and treating diseases, a sub-branch of nanotechnology was born, which is called 'nanomedicine': application of nanotechnology for healthcare.
Authors:Asmita Mittal,Meenakshi Malhotra,V.R. Swami
The Success of Swiss Biotech Industry
Excellence in Education, Basic Research and Technology Transfer
The advancement of biotechnology has been relatively rapid in the past two decades. As with any new technology, biotechnology holds a great deal of promise to enhance our lives and planet. It offers new potential for sustainable living and eating. The ripples of this wave of the future have already landed in Switzerland.
Traditionally termed as a powerhouse in pharmaceutical research and product development, Switzerland has now become one of the primary players in the international biotechnology field. As stated in Ernst & Young's, European Life Science Report of 1998, 'Europe's biotech landscape is changing dramatically for the better, and Switzerland is one of the locomotives driving this change’. Today, Switzerland has emerged as the 6th largest biotech country in Europe and 9th in the global scenario.
By the end of 2005, out of the total 523 European biotech products in development pipelines, 109 come from Switzerland. With 138 biotech companies and 91 biotech suppliers, Switzerland boasts the highest biotech density worldwide. Located in the heart of Europe, Swiss biotech is in close proximity to important biotech areas in neighboring Germany, France and Italy and is therefore a perfect gateway to the EU markets that include well over 450 million consumers.
The momentum for the current progress was set in motion largely as a result of the government's initiative in 1992 of establishing the Swiss National Science Foundation sponsored Swiss Priority Program on Biotechnology (SPP Biotech). The mission of this program which was operative until 2002, was to provide financial support for applied research and to link university-sponsored research with the industry.
Authors:K.R. Pillai,Geetha Raghuraman.
Transgenic Animals
Introduction
Molecular biotechnology has been one of the most prospective fields of science for more than three decades. Its applications are numerous and have not even come close to reaching the limit. Nowadays, breakthroughs in molecular biology are happening at an unprecedented rate. One of them is the ability to engineer animals. Prior to the development of molecular genetics, the only way of studying the regulation and function of mammalian genes was through the observation of inherited characteristics or spontaneous mutations. The mutual contributions of developmental biology and genetic engineering permitted rapid development of the techniques for the creation of transgenic animals. Perhaps the most important contribution of transgenic technology to biomedical science has been its use for determining the mechanisms by which genes become differentially regulated during mammalian development. Since all cells of the developing mammal are clonal descendants of the fertilized egg, and since all contain the same genetic information, it is critical to understand how, during the process of differentiation; tissue-specific genes are activated while most others are permanently silenced. The ability to introduce new genes in to the random sites in the genome provided an important tool for solving this puzzle.
Authors: N.Kishan Vaidyanat , K.Praveen Kumar , P. Sathiya moorthi.