Swiss
A compound that can seek out, mark and destroy cancer cells simulatiously, and a molecular probe that can accurately and non-invasively lable the mass of functional beta-cells in the pancreas – these are just two examples of compounds that Norbert Lange and his colleagues from the University of Geneva were tasked to create
agents we have developed are also photosensitisers, meaning that upon irradiation they will interact with molecular oxygen to form reactive oxygen species, which can be used to selectively destroy the cells around the agent. For example,
if we have an agent that is
designed to accumulate around tumours, we can then activate it to try and destroy the cancerous cells.” This process of locating and destroying
Seeing is curing: New compounds for diagnostic imaging
“Our research is based around finding new molecules for use in diagnostics,” explains Norbert Lange. “Our initial focus is on optical methods, as they are generally the easiest to implement in pre- experimentations but can easily adapted to a clinical setting. What we do is always applied science. We prefer to work closely with clinicians who have expressed a clinical need for a diagnostic tool or a solution to a specific problem for the benefit of their patients.” One of the main tools that Lange and his colleagues have worked on developing is
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molecules that fluoresce. These molecules can be used in a variety of different diagnostic situations, from labelling cancer cells
so that they can be more easily
removed by surgeons or to adapt a treatment strategy based on fluorescence images. These optical methods offer a far higher resolution than can be attained with other imaging methods. Already around a thousand cells can be detected in real time. As well as being useful diagnostic tools,
these molecules have properties that allow them to be part of the therapeutic process, as Lange explains: “Many of the optical
pathologies using nontoxic light-sensitive compounds is known as photodynamic therapy. One of the molecules developed for this purpose is based upon a prodrug family called aminolevulinic acid (5-ALA). These molecules are converted by metabolically over-active cells such as cancer cells into protoporphyrin IX, the penultimate precursor to haem in haem biosynthesis, and the only molecule in this process which is fluorescent. “The problem we faced was that although this 5-ALA could obviously be used for fluorescence detection, it did not pass through biological membranes easily, and so could not pass into cells unaided. Therefore, fluorescence was weak and fading,” says Lange. “What we did was to modify
aminolevulinic acid into a more lipophilic version of itself that could be easily taken up by cells but could still also be converted into the photoactive porphyrins. This modified molecule is now available on the market in the US and in Europe as an improved method of detecting bladder cancer.” A more recent aspect of Lange’s work has
been the development of new contrast agents – substances used to enhance the contrast of structures or fluids within the body – that can be used to determine the functional beta cell mass in the pancreas. The primary function of beta cells is to produce and release insulin, and so beta- cell mass can be used as an indicator for monitoring diabetes and its treatment. “The reason we developed these agents is due to the anticipated influx in novel stem cell based therapeutic approaches to types 1 and 2 diabetes,” says Lange. “It is currently not possible to follow the progress of these patients non-invasively, and it would be detrimental to the patients
Insight Publishers | Projects
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