 Bio Nanosensors
| In medical and
biochemical research, when the domain of the sample is
reduced to micrometer regimes, e.g. living cells or
their subcompartments, the real-time measurement of
chemical and physical parameters with high spatial
resolution and negligible perturbation of the sample
becomes extremely challenging. A traditional strength of
chemical sensors (optical, electrochemical, etc.) is the
minimization of chemical |
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| interferenceis the minimization of
chemical interference betweensensor and sample, achieved
with the use of inert, “biofriendly” matrices or
interfaces. However, when it comes to penetrating
individual live cells, even the introduction of a
sub-micron sensor tip can cause biological damage and
resultant biochemical consequences. In contrast,
individual molecular probes (free sensing dyes) are
physically small enough but usually suffer from chemical
interference between probe and cellular components. Our
recently developed PEBBLE sensors (Probes Encapsulated
By Biologically Localized Embedding) are nano-scale
spherical devices consisting of sensor molecules
entrapped in a chemically inert matrix. This protective
coating eliminates interferences such as protein binding
and/or membrane/organelle sequestration which alter dye
response. Conversely, the nanosensor matrix also
provides protection to the cellular contents, enabling
dyes that would usually be toxic to cells to be used for
intracellular sensing. In addition, the inclusion of
reference dyes allows quantitative, ratiometric
fluorescence techniques to be used. PEBBLEs have been
used to measure analytes such as calcium, potassium,
nitric oxide, oxygen, chloride, sodium and glucose. |
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