Dr Kai Johnsson has been working in the area of super resolution imaging and has come up with some very useful fluorescent probes for glutamate, switchable flourophores for protein labeling, caged rhodamine derivates among other research on membrane biology. His group just showed another interesting probe that can go inside the membrane and can be used in the near-infrared.
His team worked with a silicon containing rhodamine that are membrane permeable that were initially made as benzylguanine derivatives but found non-specific labeling. However, they found a modification that worked and developed other probes that were specific but also very membrane permeant. A neat feature of these probes are that they bind covalently to the proteins and thus stay bound forming a zwitterionic complex with no net charge but the unbound probe aggregate to non-fluorescent moieties.
They have used the probes to label neurons in the rat brain as well as perform super-resolution microscopy with these probes. Watch for these probes being available for more biological research.