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Posted: June 30, 2008

Colloidal nanoparticles - from synthesis to biological applications

(Nanowerk News) "Colloidal nanoparticles - from synthesis to biological applications" is a conference organized by the University of Marburg/Germany from September 15-17, 2008.
Nanobiotechnology is an emerging direction of modern research and presently founding several initiatives are established on a national and international level. As already stated in its name, "nanobiotechnology" comprises components from several disciplines, as biology / medicine and physics / chemistry / engineering.
One classical example in this direction is the biologically motivated use of inorganic colloidal nanoparticles. Inorganic colloidal nanoparticles are controlled assemblies of a few 100 up to a few 1000 atoms. Nowadays such structures can be synthesized for many different materials with controlled size, shape, and spatial composition. Though due to its colloidal nature each particle is an "individual" modern synthesis techniques allow for obtaining grams of nanoparticles, whereby basically all particles are alike.
Depending of the used inorganic material nanoparticles can have different functionalities. Metal nanoparticles can be used as photo-thermal heat source, semiconductor nanoparticles (so called quantum dots) can be used as fluorescence labels, and nanoparticles from several metals and metal oxides can be used as magnetic labels. Naturally these functional properties have attracted the attention of the life sciences, in particular regarding as new tools for manipulation, sensing, and labeling.
As examples for manipulation, magnetic nanoparticles can be used to separate molecules or cells with magnetic field gradients, or metallic nanoparticles can be used as photo-excitable heat source for the local destruction of tissue. Due to their distance dependent optical properties as well metal as semiconductor nanoparticles can be used as sensors, whereby the analyte changes the distance between the particles which can be optically detected. And finally semiconductor nanoparticles (quantum dots) can be used for fluorescence labeling of biological structures.
The advantage of inorganic materials in comparison to organic molecules is hereby their improved functionality and robustness. Inorganic colloidal magnetic nanoparticles have superior magnetic properties compared to organic magnetic molecules and colloidal quantum dots suffer less from photobleaching than organic fluorophores. On the other hand, due to their inorganic nature first an interface for these particles has to be created so that they have defined properties for the interaction with biological objects such as biomolecules, cells, and tissue.
The first interface of the particles to the "biological world" is governed by their surface chemistry. In an additional step the surface of particles can also be decorated with biological ligands, as to provide a defined interaction to receptors according to the "key-lock" principle. Though "biocompatibility" of such nanoparticles is still subject to discussion, in the last years biologically motivated applications in the directions of manipulation, sensing, and labeling have been demonstrated.
In this conference the role of inorganic colloidal nanoparticles in the life sciences will be discussed. Chemists, physicists, and engineers can synthesis particles with high precision and tailored properties, but they are often not aware of the precise nature of biological problems. On the other hand, biologically motivated scientists are bound to solve their problems with commercially available particles, which still fall behind to the state-of-the-art particles available in modern materials research concerning their homogeneity and defined properties. For this reason the conference attempts to cover the whole interdisciplinary range starting from the chemical synthesis of functional colloidal nanoparticles, the characterization of their physical properties, the design of appropriate interfaces to biology, until their use as in vitro sensors and in vivo labels in life sciences, and diagnostics in medicine.
The conference covers the three major functional classes of inorganic colloidal nanoparticles:
1) Metal nanoparticles (in particular Au), as optically excitable heat sources and optical labels
2) Semiconductor nanoparticles (quantum dots, in particular CdSe), as fluorescence labels and sensors
3) Magnetic nanoparticles (in particular FexOy and Co), as tools to manipulate biological objects
For each class of materials several speakers will be invited, which will cover the whole bandwidth from synthesis to biologically motivated applications. Therefore speakers of different background and disciplines covering chemistry, physics, engineering, pharmacy, biology, and medicine will be invited to report about colloidal nanoparticles from their respective perspectives. The talk of each speaker will be organized in a general educational part to teach the general background as well examples of the actual research from the speaker's group.
There will be presentations of 20 invited speakers. On two evenings there will be poster presentations of the participants. In order to facilitate communication lunch and dinner will be prepared together. This will give the opportunity for the participants of the conference to learn also fancy cooking recipes from all over the world (Germany, Spain, Italy, China, Pakistan, USA, etc.). This type of cooking together has already been tried great success.
Source: University of Marburg