Array and lab-on-chip technology

There is a whole series of analytical measuring instruments available that can detect biomolecules. Tools for bonding biomolecules to surfaces on a nanoscale by functionalizing or structuring has generated whole new market fields within the last few years. One of them is the lab-on-a-chip technology for special areas of biomedical diagnostic procedures that enables multiparametric microphysiological and miniaturized analysis systems. What has previously stood in the way of large-scale diagnostic application of bio-chips was the problem of the error rate that has to be pushed back dramatically. The solution will essentially be material-driven.

Point-of-care diagnostic procedures are an important sector where the trend is going in the direction of lightweight portable and multifunctional instruments to make quick quantitative analyses of blood, saliva or urine samples in domestic or out-patient use. This is an area where multifunctional materials are crucially important since they usually have to have a wide range of properties:

• chemically inert to the material analyzed (in this case, body fluids)
  
• specific to a single component, e. g. by surface functionalizing and bonding of suitable molecules
  
• structuring for to the integration of fluid or electro/optical subassemblies
  
• hydrophobic if exact amounts of fluids have to be added or measured
  
• transparent and low intrinsic fluorescence for optical analysis techniques   

Nanoparticles

The surface of nanoparticles with diameters in the 20 nm to 300 nm range can be chemically functionalized for bioanalytical applications. Antigenes or ligands (i. e., haptenes) specific to certain sets of symptoms can be detected by equipping them with specific bonding partners. The essential parameters for optimization are stability, maintaining biological activity, sensitivity, response time, selectivity, and reproducibility. The possibility of toxicity of nanoparticles resulting from their small size also requires attention by materials scientists. The interaction of nanoparticles with biological cellular components is another area that has to be researched. 

Magnetic nanoparticles are freely moving carrier materials that open the perspective of cell and nucleic acid separation from fluids that is much faster and more effective than with centrifugal or adsorptive techniques. Although there is a wide range of systems on the market in this field, there is still a major potential for developing selective extraction of biomolecule species from a solution.

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