Biology Reference
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proteins secreted by cancer cells. 33 Self-assembled carbon nanotubes and
probe DNA oligonucleotides are immobilized by covalent binding to the
nanotubes.
When hybridization between the probe and the target DNA
sequence occurs, the change is noted as a voltage peak. 35 The nano-based
biosensors being developed are more eficient and more selective than
current detectors and may be utilized as alternative and complementary
cancer detection probes.
34
20.2.4 Cell Nanomechanical Moon
Cells are dynamic structures that display nanometre to micrometre
scale motions at their cell membranes. The AFM can investigate the
nanomechanical motion of the cell surface ranging from yeast 16 to
cardiomyocytes. 36 If the AFM tip is held stationary over a cell surface that is
vibrating or moving, the tip will bend and follow these motions. The AFM can
thus be used as an ultra-sensitive, high-resolution motion detector. AFM may
be used to probe the surface of cells under a variety of external and internal
environmental conditions to obtain an oscillatory signal of nanomechanical
origin. This oscillatory, periodic signal can be converted into sound and
used as an indicator of cell health. The process termed as “sonocytology”
enables cell damage detection; for example, when microtubule and actin
dissociating agents used in chemotherapy are added, a change in cell
elasticity is discernable much earlier than biochemical measurements of
cell death. 16 Thus, by observing their motion, the healthy and cancerous
cells can be distinguished. Sonocytology may thus be used as a diagnostic
tool by analyzing variations in cell nanomechanical motions. In future,
sonocytology may be incorporated as a complementary tool into medical
disciplines such as cancer research and make cancer detection possible
before a tumour forms and signiicant cellular biophysical and biochemical
changes manifest.
20.3 SUMMARY
Nanomedicine is an emerging ield with signiicant potential to yield new
generation of scientiic and technological approaches and advance clinical
tools and devices. Diagnostics and biosensors are among the earliest
applications of nanotechnology rapidly translating from research to clinical
environments. They provide alternative and better approaches to assess the
onset or progression of diseases. Diseases such as cancer can be quantiied
based on morphological, biophysical and biochemical nanoscale properties of
 
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