Periodic Reporting for period 3 - SWIMMOT (Switchable magneto-plasmonic contrast agents and molecular imaging technologies)
Periodo di rendicontazione: 2023-04-01 al 2025-03-31
SWIMMOT established the scientific and technological basis for a radically new technique for in vivo molecular imaging based on a switchable contrast agent (CA) and corresponding optical imaging technology. Our CA was based on novel magnetic core / plasmonic gold shell nanorods with specifically engineered biofunctional shells. We developed a new magneto-plasmonic imaging technique based on magnetic excitation and plasmonic signal generation to realise multimodal optical coherence tomography / photoacoustic imaging modes. The magnetoplasmonic imaging technique turns our CA on and off, which allows removal of the imaging background. This discrimination of the background from the CA signal yields ultra-high contrast molecular imaging.
These science and technology breakthroughs pave the way for a new imaging technology that enables the detection of previously inaccessible in vivo physiology and molecular events, and elucidation of until now poorly understood biological mechanisms through studies in model organisms. This in turn contributes to a better understanding of normal processes and disease pathogenesis in the future. We applied the SWIMMOT technology for diabetes research and demonstrated its breakthrough potential by imaging zebrafish model organisms.
SWIMMOT was a four-year collaborative project of five partners with complementary expertise: AIT Austrian Institute of Technology GmbH, Institut National des Sciences Appliquées de Toulouse, Universidad de Santiago de Compostela, Medizinische Universitaet Wien, Universitaet Innsbruck.
These science and technology breakthroughs pave the way for a new imaging technology that enables the detection of previously inaccessible in vivo physiology and molecular events, and elucidation of until now poorly understood biological mechanisms through studies in model organisms. This in turn contributes to a better understanding of normal processes and disease pathogenesis in the future. We applied the SWIMMOT technology for diabetes research and demonstrated its breakthrough potential by imaging zebrafish model organisms.
SWIMMOT was a four-year collaborative project of five partners with complementary expertise: AIT Austrian Institute of Technology GmbH, Institut National des Sciences Appliquées de Toulouse, Universidad de Santiago de Compostela, Medizinische Universitaet Wien, Universitaet Innsbruck.
Initial nanorods have been successfully synthesized. These nanorods of cylindrical shape possessed a cobalt core and a multi-layered shell consisting of a first tin layer, which itself was covered by a layer of platinum and gold. The cobalt core possessed magnetic properties, but was sensitive to oxidation, which impacted the magnetic properties. The layer of platinum and gold served to protect the cobalt core from oxidation once the nanorods were exposed to air or suspended in an aqueous solution.
Advanced nanorods have been synthesized possessing a cobalt core, an intermediate tin shell and an outer shell of gold. These nanorods were plasmon active and showed a longitudinal plasmon resonance peak at about 800 nm, which fitted the wavelength of the excitation of the photoacoustic imaging technology.
The nanorods were synthesized in an organic solvent, which was not biocompatible. Thus, the nanorod surface was modified and the nanorods were transferred to aqueous media. This was achieved by using a specific polymer, which comprised hydrophobic and hydrophilic parts. This polymer was wrapped around the nanorods. By this, stable nanorod dispersions were achieved in water, in salt solutions and in cell culture media.
The specific polymer also comprised segments that were used to bind additional molecules to the nanorod surface. This was employed to bind fluorescent dyes to the nanorod surface, which enabled reference imaging by conventional fluorescence microscopy. Additionally, antibodies were bound to the nanorods’ surface to target specific cell types. Furthermore, the surface of the nanorods was bio-functionalized to allow for the binding of glucose in a competitive assay format.
The nanoparticular contrast agent was employed to test its toxic effects on cells in vitro. Here, the results showed no toxic effect on cells. Based on these findings, the in vivo nanotoxicity was assessed with living zebrafish animal models. Again, no toxic effects were observed. Thus, the contrast agent could be safely administered to living zebrafish animal models for imaging purposes.
Another key development in the project was the development of the measurement setup including optical and magnetic components and custom software for imaging purposes. Here, a microscopy and a tomography-based setup were developed. The optical imaging modalities comprised optical coherence tomography and photoacoustic imaging. Additionally, we developed a high-speed magneto-plasmonic imaging setup based on optical coherence tomography.
Zebrafish animal models were cultivated, and we developed fish lines with highly reduced pigmentation. Reference imaging was conducted by conventional fluorescence microscopy. Retinal blood vessels and beta cells in the endocrine pancreas were imaged. This also served to verify that the circulation time of nanoparticular contrast agent within the blood stream was long enough to allow for imaging.
Magneto-plasmonic imaging with all three imaging modalities (microscopy, tomography, high-speed) was tested in phantom samples and in zebrafish embryos. The measurement principle was working and allowed for background removal. The fish survived the imaging session well, which was revealed by checking the heartbeat of the fish after imaging.
The SWIMMOT project and the results achieved have been disseminated to the general public via the social media accounts of the consortium partners, via a dedicated SWIMMOT homepage and a LinekdIn account. Furthermore, we organized two open public workshops in Santiago de Compostela and in Vienna dealing with molecular imaging and the application of nanomaterials for biomedical purposes. Additionally, the project and its results were presented in scientific workshops, conferences and via peer-reviewed publications. We gave a total of 33 talks and presented 17 posters. Currently, 13 research papers were published while several more are still under preparation. All research articles were published open access. Four master students and six PhD students performed their research supported by SWIMMOT. Numerous postdoctoral fellows from all partner institutions were able to continue their research path with the help and in the frame of the SWIMMOT project. During the project, the SWIMMOT consortium already teamed up with a European company which is among the world leaders in fabricating photoacoustic imaging technology, and they are very interested to join forces for the next development steps.
Advanced nanorods have been synthesized possessing a cobalt core, an intermediate tin shell and an outer shell of gold. These nanorods were plasmon active and showed a longitudinal plasmon resonance peak at about 800 nm, which fitted the wavelength of the excitation of the photoacoustic imaging technology.
The nanorods were synthesized in an organic solvent, which was not biocompatible. Thus, the nanorod surface was modified and the nanorods were transferred to aqueous media. This was achieved by using a specific polymer, which comprised hydrophobic and hydrophilic parts. This polymer was wrapped around the nanorods. By this, stable nanorod dispersions were achieved in water, in salt solutions and in cell culture media.
The specific polymer also comprised segments that were used to bind additional molecules to the nanorod surface. This was employed to bind fluorescent dyes to the nanorod surface, which enabled reference imaging by conventional fluorescence microscopy. Additionally, antibodies were bound to the nanorods’ surface to target specific cell types. Furthermore, the surface of the nanorods was bio-functionalized to allow for the binding of glucose in a competitive assay format.
The nanoparticular contrast agent was employed to test its toxic effects on cells in vitro. Here, the results showed no toxic effect on cells. Based on these findings, the in vivo nanotoxicity was assessed with living zebrafish animal models. Again, no toxic effects were observed. Thus, the contrast agent could be safely administered to living zebrafish animal models for imaging purposes.
Another key development in the project was the development of the measurement setup including optical and magnetic components and custom software for imaging purposes. Here, a microscopy and a tomography-based setup were developed. The optical imaging modalities comprised optical coherence tomography and photoacoustic imaging. Additionally, we developed a high-speed magneto-plasmonic imaging setup based on optical coherence tomography.
Zebrafish animal models were cultivated, and we developed fish lines with highly reduced pigmentation. Reference imaging was conducted by conventional fluorescence microscopy. Retinal blood vessels and beta cells in the endocrine pancreas were imaged. This also served to verify that the circulation time of nanoparticular contrast agent within the blood stream was long enough to allow for imaging.
Magneto-plasmonic imaging with all three imaging modalities (microscopy, tomography, high-speed) was tested in phantom samples and in zebrafish embryos. The measurement principle was working and allowed for background removal. The fish survived the imaging session well, which was revealed by checking the heartbeat of the fish after imaging.
The SWIMMOT project and the results achieved have been disseminated to the general public via the social media accounts of the consortium partners, via a dedicated SWIMMOT homepage and a LinekdIn account. Furthermore, we organized two open public workshops in Santiago de Compostela and in Vienna dealing with molecular imaging and the application of nanomaterials for biomedical purposes. Additionally, the project and its results were presented in scientific workshops, conferences and via peer-reviewed publications. We gave a total of 33 talks and presented 17 posters. Currently, 13 research papers were published while several more are still under preparation. All research articles were published open access. Four master students and six PhD students performed their research supported by SWIMMOT. Numerous postdoctoral fellows from all partner institutions were able to continue their research path with the help and in the frame of the SWIMMOT project. During the project, the SWIMMOT consortium already teamed up with a European company which is among the world leaders in fabricating photoacoustic imaging technology, and they are very interested to join forces for the next development steps.
Main results beyond the state-of-the-art are:
- Nanorods with both, magnetic and plasmonic properties
- Biofunctional shell on the nanorod surface tailored to a specific medical/biological question
- Realization of a contrast agent that can be turned on and off
- Realization of multimodal optical coherence tomography and photoacoustic imaging modes
- Removal of imaging background for the new magneto-plasmonic imaging technique resulting in ultra-high contrast imaging
Potential impacts are:
- Use of the synthesized nanoparticles for catalytic applications (first proof already established)
- Uncovering new biomolecular mechanisms in zebrafish model organisms, especially with respect to diabetes-related complications and regenerative mechanisms of the endocrine pancreas
- Substantial reduction of the number of required animals for imaging purposes
- Establish a new imaging technique that can be employed for many alternative applications in fundamental science relying on zebrafish model organisms
- Support the prevention of blindness and enhance the quality of life of millions of diabetes patients.
- Nanorods with both, magnetic and plasmonic properties
- Biofunctional shell on the nanorod surface tailored to a specific medical/biological question
- Realization of a contrast agent that can be turned on and off
- Realization of multimodal optical coherence tomography and photoacoustic imaging modes
- Removal of imaging background for the new magneto-plasmonic imaging technique resulting in ultra-high contrast imaging
Potential impacts are:
- Use of the synthesized nanoparticles for catalytic applications (first proof already established)
- Uncovering new biomolecular mechanisms in zebrafish model organisms, especially with respect to diabetes-related complications and regenerative mechanisms of the endocrine pancreas
- Substantial reduction of the number of required animals for imaging purposes
- Establish a new imaging technique that can be employed for many alternative applications in fundamental science relying on zebrafish model organisms
- Support the prevention of blindness and enhance the quality of life of millions of diabetes patients.