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A New Generation of Nanotools-Nanotechnology in Biology and Medicine: Methods, Devices, and Applications

by siebo last modified December 13, 2007 - 12:21

Dr. Tuan Vo-Dinh, et al. Fitzpatrick Institute for Photonics Duke University

The combination of nanotechnology and molecular biology has produced a new generation of devices capable of probing the cell machinery and elucidating molecular-level life processes heretofore beyond the scope of human inquiry. Nanocarriers having antibodies for recognizing target species and spectroscopic labels (fluorescence, Raman) for in vivo tracking have been developed for seamless diagnostic and therapeutic operations.

Tracking biochemical processes within intracellular environments is possible with molecular nanoprobes and nanosensors. Optical nanosensors have been designed to detect individual biochemical species in subcellular locations throughout a living cell [3]. The nanosensors were fabricated with optical fibers pulled down to tips with distal ends having nanoscale sizes (30–40 nm).

Laser light is launched into the fiber and the resulting evanescent field at the tip of the fiber is used to excite target molecules bound to the antibody molecules at the nanotips. A photodetector is used to detect the fluorescence originating from the analyte molecules.

Dynamic information of signaling processes inside living cells is important to the fundamental biological understanding of cellular processes. Many traditional microscopy techniques involve incubation of cells with fluorescent dyes or nanoparticles and examining the interaction of these dyes with compounds of interest. However, when a dye or nanoparticle is incubated into a cell, it is transported to certain intracellular sites that may or may not be where it is most likely to stay and not to areas where the investigator would like to monitor.

The fluorescence signals, which are supposed to reflect the interaction of the dyes with chemicals of interest, are generally directly related to the dye concentration as opposed to the analyte concentration. Only with optical nanosensors can excitation light be delivered to specific locations inside cells.

Excerpted from:

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Nanotechnology in Biology and Medicine

Nanotechnology has revolutionized research in such fields as molecular biology and genomics by opening the possibility of detecting and manipulating atoms and molecules in individual cells. With 780+ pages, Nanotechnology in Biology and Medicine serves as an authoritative reference for those involved in the research, teaching, learning, and practice of nanotechnology.
The capability to detect important biological molecules at ultratrace concentrations in vivo is central to many advanced diagnostic techniques. Early detection of diseases will be made possible by tracking down trace amounts
of biomarkers in tissues. Nanosensors are an important technology that can be used to measure biotargets in a living cell and that does not significantly affect cell viability. Following measurements using the nanobiosensor, cells have been shown to survive and undergo mitosis.

Biomedical nanosensors, which have been used to investigate the effect of cancer drugs in cells [5], will play an important role in the future of medicine.