skip to content

Department of Chemical Engineering and Biotechnology

 

The analytical capabilities of the department have been greatly enhanced recently by the development and set-up of a state-of-the-art fluorescence lifetime imaging microscope (FLIM). This system enables us to obtain chemical information not only from the intensity of light emitted from molecules of interest but also from the lifetimes of emitted signals which may last for only a billionth of a second or less. Fluorescence lifetimes are strongly affected by the molecular environment of the emitting species. For example, the presence of oxygen or ion species quenches fluorescence and thus strongly reduces the lifetime of most fluorophores. The laser analytics group of Dr. Kaminski is developing this technology for diagnostics of microscale environments such as living cells or microreactors.

flim An example of such research, conducted in collaboration with Dr. A. Fisher's group at this department and Dr. J. Frank from Sandia National Laboratories, USA, is displayed in the figure, which shows two microchannels merging into a single channel from right to left. The top channel carries Rhodamine dye dissolved in an aqueous solution of KCl, merging with a stream of Rhodamine dye dissolved in KI from the bottom channel. Flows are from right to left, the width of the merged channel is ~300 µm and flow speeds are about 1 mm sec-1. The circular feature is an air bubble sticking to the side of the channel wall. The top image shows a conventional fluorescence image of the system, but there is very little contrast between the fluid streams, because the fluorophores across the image display similar levels of emission.

flim The bottom image shows the result using FLIM. Lifetimes in the KI stream are much shorter (around 2x10-9 s) compared to the KCl stream (4.5x10-9 s). In the laminar boundary layer between the two flows a gradual change from shorter to longer lifetimes can be clearly observed. A stagnating layer of KI fluid around the bubble leads to locally low lifetimes there.

Dr. Kaminski's and Dr. Fisher's groups will use this technology to study reactions at the interface of immiscible liquids flowing through such devices and were recently awarded an EPSRC grant for this work. 

Latest news

'The science of small things': Ljiljana Fruk gives TEDx talk on bio-nanotechnology in medicine

12 December 2019

Watch Dr Ljiljana Fruk, head of our Bionano Engineering group, share her research into bio-nano hybrid materials for medical diagnostics, targeted drug delivery and tissue engineering at TEDx Koenigsallee in Germany.

Alumna Deborah Grubbe President-elect of AIChE

6 December 2019

Alumna and former Winston Churchill Scholar Deborah Grubbe has been named President-elect 2020 of the American Institute of Chemical Engineering (AIChE)

MBE students in highlight city event on tackling air pollution

6 December 2019

Our MPhil in Bioscience Enterprise students Adam Karlsson and Sven Hollmann on 'Tackling Toxic Air Pollution in Cities' event organised by the Centre on Global Health Security at Chatham House in London