A team of researchers in Ireland has collaborated on developing a new fluorescent molecular probe that can hone in on and light up cancer in an exciting new way. The technology will hopefully have important consequences for cancer resection surgeries, allowing physicians to remove tumors while sparing healthy tissues.
Previously developed fluorescent molecular probes are hampered by the fluorescence of some naturally-occuring molecules within our bodies. The signal-to-noise ratio is not very high and it takes a while for such probes to accumulate in and sufficiently illuminate a tumor. However, this team created what they describe as “off to on” bio-responsive fluorophores, that operate in the near-infrared range, and that can switch on only when they reach a tumor. By tracking where these appear, it is possible to more confidently trace the margins of a given tumor.
Some details, according to the study abstract in journal Chemical Science:
Bio-responsive cRGD, iRGD and PEG conjugates have been synthesized using activated ester/amine or maleimide/thiol couplings to link targeting and fluorophore components. Their off to on emission responses were measured and compared with an always-on non-responsive control with each bio-responsive derivative showing large fluorescence enhancement values. Live cell imaging experiments using metastatic breast cancer cells confirmed in vitro bio-responsive capabilities. An in vivo assessment of MDA-MB 231 tumor imaging performance for bio-responsive and always-on fluorophores was conducted with monitoring of fluorescence distributions over 96 h. As anticipated, the always-on fluorophore gave an immediate, non-specific and very strong emission throughout whereas the bio-responsive derivatives initially displayed very low fluorescence. All three bio-responsive derivatives switched on within tumors at time points consistent with their conjugated targeting groups.