Darkfield Microscopy. Science and the self.

A typical illustration of a darkfield microscope set up.

I am looking at darkfield microscopy techniques in both my science brief and in ideas about the self as a portrait. I am not only interested in the self as this collection of cells normally unfamiliar (body and mind separation) certainly in terms of our own, but I am also interested in the scientific process of capturing this micro world of information and the impact that medicine has upon us. An impact not only in terms of our general ideas about our personal response (within the culture) to science through cellular investigation but also the subsequent affect on the 'self' resulting from an outcome which is usually 'diagnostic', in some way.

I have approached a laboratory and I will be having several samples taken for this project that will be examined using the darkfield microscopy techniques as per the illustration. I will be able to view highly detailed images of my cells and record these and save them to a usb memory stick. The act alone of having blood and other samples taken that will be sent to a portable data storage device which in essence converts an image of life into 1's and 0's for decoding by the appropriate recipient device says something redolent about; progress, systems, knowledge, privacy and ideas about where the self actually exists.

Medicine and science are able to explore, capture and diagnose the fundamental essence of us as pure biological organisms but questions of how far we can get from that base point to a fuller understanding of the complexity of the self are hugely more difficult. There is a current backlash in psychology regarding the number of papers being published that increasingly extrapolate modes of behaviour (even belief) from advances in neuroscience and PET scan imaging. There has also been a recent acknowledgement by genetic scientists regarding the human genome project. They have outlined that despite the mapping of the genome and the possibility of identifying certain genes as performing certain functions it is becoming increasingly apparent that the complexity of interactions between one gene and others outside of their apparent individually ascribed function is beyond our ability to understand or measure.

Darkfield microscopy is a simple and popular method for rendering unstained and transparent specimens clearly visible. Good candidates for darkfield observation often have refractive indices very close in value to that of their surroundings and are difficult to image with conventional brightfield techniques. As an example, small aquatic organisms, oocytes, and cells in tissue culture have a refractive index ranging from 1.2 to 1.4, resulting in a negligible optical difference from the surrounding aqueous medium (refractive index of 1.3). These and similar specimens are ideal candidates for observation with darkfield illumination techniques.

Darkfield is the method whereby the sample being viewed is actually in front of a dark background and light is being angled onto the sample from the sides. Under phase contrast conditions, the light coming through the specimen is shifted into two beams, one slightly out of phase with the other.

Both the techniques of darkfield and phase contrast allow nearly invisible microorganisms within the blood to be “lit up” and seen. It also clearly delineates the blood cells. This method is in contrast to the standard microscope “brightfield” conditions where light shines directly through the viewed sample, and invisible particles remain invisible.

 

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