Autofluorescence imaging

Trieschmann, M. et al. (2003). Macular pigment Quantitative analysis on autofluorescence images. Graefe s Archive for Clinical and Experimental Ophthalmology 241 1006-1012. 

Delori FC (2004), Autofluorescence method to measure macular pigment optical densities Fluorometry and autofluorescence imaging, Arch. Biochem. Biophys. 430 156-162. 

Rocheleau JV, Head WS, Piston DW (2004a) Quantitative NAD(P)H/flavoprotein autofluorescence imaging reveals metabolic mechanisms of pancreatic islet pyruvate response. J Biol Chem 279 31780-31787 Rocheleau JV, Walker GM, Head WS, McGuinness OP, Piston DW (2004b) Microfluidic glucose stimulation... 

Although macroscopic scanning systems for multispectral time-resolved fluorescence imaging can be built with reasonable technical effort, no such system is yet available. There are, however, microscopy systems for autofluorescence imaging. These systems are described below. 

Fig. 5.67 Time-resolved in-vivo autofluorescence images of human stratum corueum (upper row, 5 pm deep), and stratum spmosum (lower row, 50 mm deep). Left to right, fast lifetime component, ri, slow lifetime component, t2, ratio of the lifetime components, Ti / Tj, and ratio of amplitudes, a / 02- The indicated parameter range corresponds to a colour range from blue to red...

The application of an ophthalmic scanning TCSPC system to autofluorescence imaging at the fundus is described in [450, 451, 452, 453, 454]. A typical result is shown in Fig. 5.69. A double-exponential deconvolution was run on the complete pixel array. It delivered a fast lifetime component of the order of T = 400 ps and a... 

A system specialised for diagnostie autofluorescence imaging of skin is de-seribed in [282, 283]. Typieal results are shown in Fig. 5.67, page 126. Other applieations of two-photon TCSPC FLIM with nondescanned deteetion are de-seribed in [7, 15, 16, 45, 46, 62, 68, 93, 147, 161, 372]. 

A considerable improvement can be expected from the application of TCSPC to autofluorescence imaging of tissue. As mentioned in the application section of this book, the fluorescence lifetime helps not only to separate the different types of fluorescence but also to characterise the state of their binding to proteins, lipids, or DNA, as well as the oxygen saturation or the pH of the tissue. The first steps have been taken in time-resolved two-photon microscopy. The same basie optieal principles are leading to imaging of macroscopic samples. 

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