During the past two decades, biosensors have been developed for environmental,industrial, and biomedical diagnostics. The application of nanotechnology to biosensor design and fabrication promises to revolutionize diagnostics and therapy at the molecular and cellular levels. The convergence of nanotechnology, biology, and photonics opens the possibility of detecting and
manipulating atoms and molecules using a new class of fiberoptic biosensing and imaging nanodevices. These nanoprobes and nanosensors have the potential for a wide variety of medical uses at the cellular level.
The potential for monitoring in vivo biological processes within single living cells, e.g. the capacity to sense individual chemical species in specific locations within a cell, will greatly improve our understanding of cellular function,thereby revolutionizing cell biology. Over the past few years, nanoprobes have already demonstrated the capability to perform biologically relevant measurements inside single living cells.
A fiberoptic nanosensor is a nanoscale probe that basically consists of a biologically or chemically sensitive layer that is covalently attached to an optical transducer. Biological sensing elements can be either a biological molecular species (e.g. an antibody, an enzyme, a protein, or a nucleic acid) or a living biological system (e.g. cells, tissue, or whole organisms) that uses a biochemical mechanism for recognition. In the case of a receptor-based nanosensor, an interaction between the immobilized receptor and its substrate—the molecule it binds to—produces a perturbation that the optical transducer converts to an electrical signal via laser-induced fluorescence.
Tuan Vo-Dinh, professor of biomedical engineering and chemistry and director of the Fitzpatrick Institute for Photonics at Duke University’s Pratt School of Engineering, in the USA, has devoted extensive research and development to the development of a variety of fiberoptic chemical nanosensors and nanobiosensors.
Vo-Dinh explains that preparing fiberoptic nanosensors is fairly straightforward if one has the right tools and good practice. ‘‘Using the so-called ‘heat and pull’ method, a micron-scale diameter silica optical fiber is placed in a commercially available puller that heats the fiber using a carbon dioxide laser and then pulls the fiber to the desired thickness, usually between 20 and 100nm in diameter. The pulled fiber is then cut in half, yielding two nanoscale fiber tips. Subsequently, vapor deposition is used to deposit a thin layer of silver, aluminium, or gold on the side walls of the tip, followed by a two-step chemical treatment of the tip that provides covalent attachment points for the biosensor molecules.’’
The need for fast and specific assays has induced researchers to explore alternative optical detection technologies for diagnostic applications. In addition to the nanobisensor technology, Vo-Dinh and co-workers have developeda new type of nanoprobe using Raman and surface enhanced Raman spectroscopy (SERS) detection.
‘‘Because of the inherently small Raman cross-section, Raman spectroscopy has not been widely used in the past for trace analysis,’’ says Vo-Dinh.‘Nevertheless, there has been a renewed interest in Raman techniques as a result of the discovery of the SERS effect.’’ In SERS, the Raman effect is found to be greatly enhanced when it is close to a rough metal surface consisting of gold or silver nanoparticles, as a result of surface plasmon resonance. In recent years it has been demonstrated that detection of single molecules with SERS is possible.
Vo-Dinh points out that a significant advantage of nanobiosensors for cell monitoring is the minimal invasiveness of the technique. This makes optical nanobiosensors promising tools for dynamic analyses of proteins in biochemical pathways within single living cells.
‘‘These optical nanoprobes provide a new method in cell-based assays offering highly miniaturized nanoscale devices that make cell-based analysis accessible at the single-cell level,’’ says Vo-Dinh. ‘‘Future applications of optical nanoprobes could include multianalyte detection and analysis of protein-protein interactions and similar analyses of other proteins involved in cellular biochemical pathways
Featured scientist: Tuan Vo-Dinh
Organization: Fitzpatrick Institute for Photonics, Duke University’s
Pratt School of Engineering, Durham, NC, USA
Relevant publication: Tuan Vo-Dinh, Paul Kasili, Musundi Wabuyele:
Nanoprobes and nanobiosensors for monitoring and imaging
individual living cells. Nanomed. Nanotechnol. Biol. Med. 2, 22–30.
Source
Nano-Society
www.rsc.org/nanoscience
manipulating atoms and molecules using a new class of fiberoptic biosensing and imaging nanodevices. These nanoprobes and nanosensors have the potential for a wide variety of medical uses at the cellular level.
The potential for monitoring in vivo biological processes within single living cells, e.g. the capacity to sense individual chemical species in specific locations within a cell, will greatly improve our understanding of cellular function,thereby revolutionizing cell biology. Over the past few years, nanoprobes have already demonstrated the capability to perform biologically relevant measurements inside single living cells.
A fiberoptic nanosensor is a nanoscale probe that basically consists of a biologically or chemically sensitive layer that is covalently attached to an optical transducer. Biological sensing elements can be either a biological molecular species (e.g. an antibody, an enzyme, a protein, or a nucleic acid) or a living biological system (e.g. cells, tissue, or whole organisms) that uses a biochemical mechanism for recognition. In the case of a receptor-based nanosensor, an interaction between the immobilized receptor and its substrate—the molecule it binds to—produces a perturbation that the optical transducer converts to an electrical signal via laser-induced fluorescence.
Tuan Vo-Dinh, professor of biomedical engineering and chemistry and director of the Fitzpatrick Institute for Photonics at Duke University’s Pratt School of Engineering, in the USA, has devoted extensive research and development to the development of a variety of fiberoptic chemical nanosensors and nanobiosensors.
Vo-Dinh explains that preparing fiberoptic nanosensors is fairly straightforward if one has the right tools and good practice. ‘‘Using the so-called ‘heat and pull’ method, a micron-scale diameter silica optical fiber is placed in a commercially available puller that heats the fiber using a carbon dioxide laser and then pulls the fiber to the desired thickness, usually between 20 and 100nm in diameter. The pulled fiber is then cut in half, yielding two nanoscale fiber tips. Subsequently, vapor deposition is used to deposit a thin layer of silver, aluminium, or gold on the side walls of the tip, followed by a two-step chemical treatment of the tip that provides covalent attachment points for the biosensor molecules.’’
The need for fast and specific assays has induced researchers to explore alternative optical detection technologies for diagnostic applications. In addition to the nanobisensor technology, Vo-Dinh and co-workers have developeda new type of nanoprobe using Raman and surface enhanced Raman spectroscopy (SERS) detection.
‘‘Because of the inherently small Raman cross-section, Raman spectroscopy has not been widely used in the past for trace analysis,’’ says Vo-Dinh.‘Nevertheless, there has been a renewed interest in Raman techniques as a result of the discovery of the SERS effect.’’ In SERS, the Raman effect is found to be greatly enhanced when it is close to a rough metal surface consisting of gold or silver nanoparticles, as a result of surface plasmon resonance. In recent years it has been demonstrated that detection of single molecules with SERS is possible.
Vo-Dinh points out that a significant advantage of nanobiosensors for cell monitoring is the minimal invasiveness of the technique. This makes optical nanobiosensors promising tools for dynamic analyses of proteins in biochemical pathways within single living cells.
‘‘These optical nanoprobes provide a new method in cell-based assays offering highly miniaturized nanoscale devices that make cell-based analysis accessible at the single-cell level,’’ says Vo-Dinh. ‘‘Future applications of optical nanoprobes could include multianalyte detection and analysis of protein-protein interactions and similar analyses of other proteins involved in cellular biochemical pathways
Featured scientist: Tuan Vo-Dinh
Organization: Fitzpatrick Institute for Photonics, Duke University’s
Pratt School of Engineering, Durham, NC, USA
Relevant publication: Tuan Vo-Dinh, Paul Kasili, Musundi Wabuyele:
Nanoprobes and nanobiosensors for monitoring and imaging
individual living cells. Nanomed. Nanotechnol. Biol. Med. 2, 22–30.
Source
Nano-Society
www.rsc.org/nanoscience
No comments:
Post a Comment