Biochips

Dear Colleagues,

Mainly due to the multiplexing capability enabling in parallel analysis at the same time of up to thousands of different biorecognition events recorded in a miniaturized device, biochip technology revealed a fast-maturating field during the last decades. The analysis platform which benefits from contributions of different disciplines such as material science, synthetic chemistry, chemical biology, and engineering, leads to tremendous cost and time savings and, therefore, offers a multitude of applications, such as in drug discovery, genomics, proteomics, biomarker discovery, food and environment safety, and point-of-care-medical analysis. Depending on single-use /reuse capability, biochips are made from different rigid substrates such as glass, silicon, quartz, or plastic on which biological material is placed for analysis. At the early beginning, most attention was devoted to DNA chips but later applications involve the use of advanced bioactive surfaces which may control or monitor communication at molecular and cellular level with other biological objects such as proteins, polysaccharides, tissues, living cells, and small organic molecules. The basic principle of operation of  a biochip consists of (1) functionalization onto different positions on the chip surface or the channel walls using, e.g., robotic spotting or lithography, (2) biointeraction when the chip is coming into contact with the target compound, (3) readout with an appropriate technique, e.g., an optical scanner, a charge-coupled device (CCD) imager or electrochemically, after all non-bound molecules were removed and, (4) evaluation of the results using special software. There is an increasing interest for label-free detection methods, like atomic force microscopy (AFM), mass spectrometry, and surface plasmon resonance (SPR). Also, the  immobilization procedure is a field in which new methods are developed very frequently, mainly focussed on using covalent and site-specific techniques in order to retain natural conformation and activity of biomolecules and prevent nonspecific binding of sample constituents. Nanotechnology, e.g., nanobeads preparation and arraying techniques and particle lithography, is expected to provide new materials and solutions to enhance biochip characteristics.

Prof. Dr. Dietmar Knopp
Guest Editor