Nanotechnology is concerned with almost anything and everything due to their nanoscale size. Nanomedicine is the application of nanotechnology in medicine like nanosurgery, tissue engineering and targeted drug delivery.
Nanotechnology refers to the design, characterization, production and application of structures, devices and systems which have novel physical, chemical and biological properties by controlling the size and shape at a nanoscale.
Nanotechnology has now diversified in a large scale. A lot of development has taken place in this sector over the last few years. Nanomedicine is an application of nanotechnology in medicine which promises better therapy and diagnostics.
In hospitals for centuries the good old surgical instruments are being used. Nanosurgery has taken a step forward. Nanosurgery at the level of living cells has been done. Some promising nanosurgery techniques are use of atomic force microscopy (AFM) with a nanoneedle and femtosecond laser surgery.
Atomic Force Microscopy (AFM)
Surgery on living cells at nanoscale using AFM and an AFM probe was done by a Japanese group. AFM is where a probe is scanned across the sample to obtain information about the surface. This can be done by a modified probe. An AFM probe is 3µm pyramid with about 30nm radius on the end of cantilever which bends as the properties of sample change. Properties of cell surface where investigated by contacting and indenting the cell surface with an AFM probe in shape of a nanoneedle. Nanoneedles penetrate both the cellular and nuclear membranes and are rightly inserted in nucleus. This has an advantage over older methods. This does not cause fatal damage to living cells. This method can also perform therapy on living cells.
Femtosecond Laser Surgery
Femtosecond near-infrared laser pulses can be used to perform surgery of nanometer- sized structures inside living cells and tissues without damage. This is achieved by high light intensity by diffraction- limited focusing of radiation of an NIR femtosecond laser on a subfemtolitrie volume. This energy delivered breaks chemical bonds without causing side effects to surrounding tissues. Femtosecond laser knocks out an individual plamid or part of organelle without affecting adjacent tissues.
The use of these techniques seems interesting however one must keep in mind the potential harms. Risk assessment is a must for all these techniques. Statements of risk are both descriptive and evaluative. They are descriptive in as much as they state the probability that harmful events will occur, and they are evaluative in as much as they attach a value to the occurrence or prevention of the events. In the field of biomedicine, the term benefit refers to something of positive value, such as life or health. The risk-benefit relationship may be conceived in terms of the ratio between the probability and magnitude of an anticipated benefit and the probability and magnitude of an anticipated harm. Use of the terms risk and benefit necessarily involves an evaluation. In the case of nanosurgery we need to compare the risk-benefit ratio of nanosurgery techniques with the risk-benefit ratio of already established microsurgery techniques. As described above, nanosurgery techniques using AFM with a nanoneedle have several advantages over traditional microinjection of proteins, peptides, and genetic material into living cells using microcapillaries. Damage stemming from the use of microcapillaries due to the shape of the capillaries and the inaccuracy of the displacement is problematic in relation to the manipulation of many cell types. The advantages of the AFM system are the accuracy of the needle and that the ultrathin needle does not cause fatal damage to living cells.
The use of femtosecond laser pulses has the advantages of minimal ablation threshold, low transfer of optical energy into destructive mechanical energy, and the absence of thermal damage to surrounding structures compared to the nanosecond pulses used in conventional microsurgery. This indicates that the risk-benefit ratio of nanosurgery techniques is smaller than the risk-benefit ratio of already established microsurgery techniques. However, the exact risk-benefit ratios need to be based on detailed experiments.
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