Time resolved in cellulo studies on luminescent metal complex-based cell probes
Lead Research Organisation:
University of Sheffield
Department Name: Chemistry
Abstract
In Sheffield, the Thomas group have developed a series of metal complexes that can be used as cellular optical imaging probes for confocal microscopy. These probes work through luminescence, so their cell location can only be imaged when they are emissive. At the same time, in Jena, the Dietzek group have developed an entirely new, and currently unique, microscope technology: Transient Absorption Microscopy. This time resolved technique allows the photoexcited states of molecules to be probed within cells.
In this six week study, probes developed in the Thomas lab will be investigated in Jena using TAM. This work has a number of aims. First, since the probes have distinctive photo-absorption profiles, their localization across a cell can be "mapped" even if they are not luminescent in that part of the cell. One of the complexes to be studied "turns on" its luminescence only when bound to nuclear DNA. The high-resolution maps will allow us to investigate where else in the cell the probe localization. In cell free studies, the emission from a second probe is "switched off" when it binds to DNA. This effect has been seen before and it is due to the DNA quenching the probe emission through a light activated electron transfer from the DNA to the metal complex. This kind of process is also known to occur when DNA is damaged by exposure to sunlight and is a cause of aging and even cancer genesis.
In unpublished work involving cells, it is clear that the probe is taken up by cells and shows emission from several intracell locations, but there is no luminescence from DNA within the nucleus. It is possible that the probe does not get into the nucleus at all, but it seems likely that the effect is due to DNA quenching within cells. The experiments in Germany will resolve thus issue and potentially provide the first opportunity to investigate within cells an important photochemical process involving DNA.
In this six week study, probes developed in the Thomas lab will be investigated in Jena using TAM. This work has a number of aims. First, since the probes have distinctive photo-absorption profiles, their localization across a cell can be "mapped" even if they are not luminescent in that part of the cell. One of the complexes to be studied "turns on" its luminescence only when bound to nuclear DNA. The high-resolution maps will allow us to investigate where else in the cell the probe localization. In cell free studies, the emission from a second probe is "switched off" when it binds to DNA. This effect has been seen before and it is due to the DNA quenching the probe emission through a light activated electron transfer from the DNA to the metal complex. This kind of process is also known to occur when DNA is damaged by exposure to sunlight and is a cause of aging and even cancer genesis.
In unpublished work involving cells, it is clear that the probe is taken up by cells and shows emission from several intracell locations, but there is no luminescence from DNA within the nucleus. It is possible that the probe does not get into the nucleus at all, but it seems likely that the effect is due to DNA quenching within cells. The experiments in Germany will resolve thus issue and potentially provide the first opportunity to investigate within cells an important photochemical process involving DNA.
Planned Impact
This project has a range of beneficiaries. In the first case, Dr Stuart Archer will receive training and gain experience in a cutting edge, currently globally unique, microscope facility. The activity will also provide a launching pad to develop a new, potentially long term, international collaboration. Outside the collaboration, academics working in the same field will benefit from the high impact publications to which the project will lead.
In the medium term, the development of new microscope technology and the insights into a common mechanism of cell damage will have impacts in cell biology and medical research, Therefore it may become relevant to the wide range of SMEs, larger medical-based companies and charities
In the longer term, the development of photoactive complexes as anticancer therapeutics will have potential impacts for society in general.
In the medium term, the development of new microscope technology and the insights into a common mechanism of cell damage will have impacts in cell biology and medical research, Therefore it may become relevant to the wide range of SMEs, larger medical-based companies and charities
In the longer term, the development of photoactive complexes as anticancer therapeutics will have potential impacts for society in general.
People |
ORCID iD |
James Thomas (Principal Investigator) |
Publications
A AH
(2018)
Polysulfide-triggered fluorescent indicator suitable for super-resolution microscopy and application in imaging.
in Chemical communications (Cambridge, England)
Ali F
(2018)
Tracking HOCl concentrations across cellular organelles in real time using a super resolution microscopy probe.
in Chemical communications (Cambridge, England)
Archer SA
(2019)
A dinuclear ruthenium(ii) phototherapeutic that targets duplex and quadruplex DNA.
in Chemical science
Singh H
(2019)
Two photon excitable graphene quantum dots for structured illumination microscopy and imaging applications: lysosome specificity and tissue-dependent imaging.
in Chemical communications (Cambridge, England)
Description | We have now developed a method to visualize the excited state of two metal complexes in treated cells. One of these complexes has a long lived excited state when bound to DNA, the other is oxiized by DNA and we have preliminary evidence that we can visualize the consequent oxidization of DNA through this technique |
Exploitation Route | Along with our partners we are developing an entirely new method to explore complex light-driven process within cells. This technique has the potential to be used in many different labs. |
Sectors | Healthcare,Pharmaceuticals and Medical Biotechnology,Other |
Title | In cell time-resolved absorption spectroscopy probes |
Description | We are using the absorption signature of a metal complex to investigate light-driven redox processes within cells |
Type Of Material | Technology assay or reagent |
Year Produced | 2017 |
Provided To Others? | No |
Impact | this could potentially be used to explore light-driven mutagenic processes |
Description | Collaboration with Jena |
Organisation | Leibniz Association |
Department | Leibniz Institute of Photonic Technology |
Country | Germany |
Sector | Academic/University |
PI Contribution | A PDRA from my group is currently carrying out time-resolved in cell studies on some of the complexes synthesized in this grant. |
Collaborator Contribution | Prof Benjamin Dietzek's labhas vdevlkopoed the specialized microscope system that is being used. |
Impact | Ms in preparation |
Start Year | 2017 |
Description | Pint of Science |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Based on some of the research funded by this grant I regulalry doing Pint of Science presentations on the issue of chirality and biology. |
Year(s) Of Engagement Activity | 2017,2018,2019,2022 |