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ANALYTICAL CURRENTS Replicating DNA microarrays ssDNA
Richard Crooks and colleagues at the University of Texas at Austin have developed a new approach for producing DNA microarrays. The method makes it possible to use a master DNA array to produce replicate arrays of proteins, carbohydrates, nanoparticles, or any other material that can be labeled with a short oligonucleotide. The new approach involves a code sequence, which is complementary to a specific code on the master, and a functional sequence, which contains biotin. The code sequence is hybridized to the master, and the replica surface, which contains streptavidin, is brought into contact with the master surface. When the two
Functional sequence Hybridization
surfaces are separated, Code 3 1 2 3 1 2 sequence the functional and code Master Master sequences are attached Contact and to the replica. The sur face reaction original code on the Replica Streptavidin Replica master remains on the master surface. Biotin The researchers 2 3 Separation 1 replicated three miMaster croarrays from one master without any sig- New strategy for replicating DNA microarrays. nificant loss of oligonuthe future, they plan to create larger-scale cleotide density on the replica. They also arrays with smaller spot sizes and include demonstrated that the approach can be more complex biological materials, such used with master arrays containing three as proteins and viruses. (J. Am. Chem. different sequences. For those arrays, Soc. 2006, 128, 3268–3272) replica spots were as small as 100 µm. In
Electrochemical aptamer sensor
MB
O
Kevin Plaxco, Alan Heeger, and colleagues
gave the best results with a Kd
at the University of California, Santa Bar-
of ~90 µM and detection limits
H3CO
bara, have developed an electronic aptamer-
