Buonasera a tutti, trovo solo ora il tempo per riprendere dopo tanti mesi l'argomento e per dimostrare che la mia provocazione ha dei concreti fondamenti...
A pagina 128 del volume “Practical Digital Photomicrography” del Dr Brian Matsumoto potete leggere “DIC is extremely sensitive for observing fine structures. It can provide sufficient contrast to detect objects
smaller than the resolving power of the microscope. DIC has been used to visualize single
microtubules – protein polymers that are 0,025 microns in width, or almost one-tenth the limiting resolution of the microscope. Moreover DIC is amenable to computer-generated contrast enhancement. This provides even more sensitivity in detecting minute objects”. Si tratta fra l'altro uno dei tanti esempi che avvalorano la grande utilità scientifica del DIC, giusto per rispondere a una recente ed interessante discussione aperta da un altro utente del forum.
Tornando all'argomento in oggetto ecco due esempi di pubblicazioni scientifiche che dimostrano come con una buona camera, un buon pc e un ottimo microscopio ottico da ricerca sia possibile raggirare/superare il limite risolutivo:
a) “
Visualizing individual microtubules using bright-field microscopy” di Braulio Gutiérrez-Medina (Department of Biology, Stanford University) e Steven M. Block (Department of Applied Physics, Stanford University) in American Journal of Physics, novembre 2009
Di seguito alcune interessanti citazioni: “
Microtubules are filament-shaped, polymeric proteins (~25 nm in diameter) involved in cellular structure and organization.
We demonstrate the imaging of individual microtubules using a conventional bright-field microscope, without any additional phase or polarization optics. Light scattered by microtubules is discriminated through extensive use of digital image-processing, thus removing background, reducing noise and enhancing contrast. (…) Using a simple setup, we have demonstrated that individual microtubules can be visualized through
video-enhanced, bright-field microscopy.” L'articolo è scaricabile comodamente da internet facendo una semplicissima ricerca on-line.
b) Salmon, E. and Tran, P., High-resolution video-enhanced differential interference contrast (VE-DIC) light microscope., Video Microscopy, Sluder, G. and Wolf, D. (eds), Academic Press, New York, pp. 153–184 (1998).
Di seguito una citazione: “In the early 1980s Allen, Ionué and others discovered that the electronic contrast enhancement capabilities of
video cameras could make visible the fine structural detail barely resolvable by the DIC microscope and structures such as 25 nm diameter microtubules which are nearly an order of magnitude smaller than the diffraction limit.
Both cameras and digital image processors have advanced significantly since the early 1980s and now video-enhanced DIC methods are easily implemented “
Buon approfondimento!
Stefano