With selected biomolecules bound to nanostructure surfaces, new hybrid nanostructures can be obtained for optical biosensing and imaging. However, the idea of merging biological and non-biological systems at the nanoscale is not a new one. The broad field of bioconjugate chemistry is based on combining the functionalities of biomolecules and non-biological molecular http://www.selleckchem.com/products/lapatinib.html species for specialized use in various different applications. Many current applications of nanostructures in biotechnology are a natural evolution of this approach. In fact, several of the most recently demonstrated applications Inhibitors,Modulators,Libraries using nanostructure�Cbiomolecular hybrids are in fact traditional ones originally addressed by standard molecular bioconjugate techniques that have been revisited with newly designed nanostructure hybrids.

The interest in the replacement of conventional molecular tags, such as fluorescent chromophores, with nanostructures resides in the superior physico-chemical properties of nanostructures compared to the molecular species they replace [6,7]. These include issues such as higher quantum efficiencies, greater scattering or absorbance cross sections, optical activity Inhibitors,Modulators,Libraries over more biocompatible wavelengths and significantly Inhibitors,Modulators,Libraries increased chemical and photochemical stability [8,9]. The systematic control of nanostructure properties obtained by controlled variations in particle size and dimension is in direct contrast to molecular tags, whose properties vary nonsystematically between molecular species.

This systematic variation of properties not only improves traditional applications, but also leads to new unique Inhibitors,Modulators,Libraries applications well beyond the scope of conventional molecular bioconjugates. The availability of these new nanostructures will greatly facilitate new in situ probes and sensor methods.In the present work, the most significant applications of semiconductor nanostructures in the field of optical biosensing will be reviewed. In particular, the use of quantum dots as fluorescent bioprobes, which is the most widely used application, will be discussed. In addition, the use of some other nanometric structures in the field of biosensing, including nanoporous semiconductors and photonic crystals, will be discussed.2.?Semiconductor Quantum-Dot-Based BiosensorsThe most common method of detecting and quantifying biomolecules still remains the use of fluorescence [5,7], which involves the use of fluorescent labels.

The earlier classes of these labels included organic dyes, fluorescent proteins and Dacomitinib lanthanide chelates, which are still commonly used mainly because of their small size, ease of usage and the existence of standard protocols for their bioconjugation. A vast library of fluorophores has been synthesized over time, many of which currently are designed for very specific applications.