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The Diamond Revolution in Hyperpolarized MR Imaging – Novel Platform and Nanoparticle Targeted Probe

Periodic Reporting for period 3 - HYPERDIAMOND (The Diamond Revolution in Hyperpolarized MR Imaging – Novel Platform and Nanoparticle Targeted Probe)

Reporting period: 2019-01-01 to 2020-06-30

The ability to recognise molecular processes using novel imaging techniques is of fundamental importance for medicine, biology and biochemistry in the 21st century. Non-invasive molecular imaging has gained widespread use in patient management of cancer as well as in research in the life-sciences and the medical sciences, as well as in drug discovery and development. The capability of non-invasive metabolic profiling is expected to impact dramatically patient management for socioeconomically relevant diseases. Spatially-resolved observation of metabolites will be key for enabling more accurate staging of diseases by direct assessment of the underlying impact on the metabolism and has thus the potential to revolutionize staging and management of diseases in cardiology, neurology, oncology and other fields.

Technologies for imagining non-invasively small numbers of molecular probes to help elucidate particular targets or pathways in vivo is currently undergoing a technological revolution. Recent breakthroughs in molecular hyperpolarization (HP) proved > 10,000-fold increase in sensitivity on conventional magnetic resonance imaging (MRI) systems, thus providing insight into previously unseen metabolic processes with enormous potential for socioeconomic relevant diseases ranging from cancer to heart disease. Pyruvate-based HP imaging for example was clinically demonstrated to be effective for prostate cancer diagnostics in human patients. However, the current state-of-the-art HP methods are expensive and cumbersome, limiting the access to HP technology, and require long HP times of 60-90 minutes per dosage; HP probes exhibit short HP duration (1-5 minutes), limiting the usage of HP to metabolic imaging. A quantum technological breakthrough, nitrogen-vacancy defects (NV centres) in diamonds, is set to revolutionize the field of HP for both hyperpolarizer and probes.
In order to achieve the project goals, the HYPERDIAMOND consortium has structured the work to be undertaken in three scientific-technical work packages (WP) for establishing the enabling technologies, two innovation focused WP, a preclinical imaging WP, a benchmarking WP for final assessment of the produced results, and two Workpackages for project management, dissemination and exploitation. In WP1 the consortium has developed HP techniques in close collaboration between experiment and theory. WP2 material scientists developed the required diamond materials for which, in WP3, chemistry developed the required diamond functionalization methods. Building on this, in WP4 our SME partner NVision pursued the development of the physical diamond hyperpolarizer capable of polarizing external molecules on a macroscopic scale (100 – 200 nL). Under WP5 biomedical scientists developed MRI probes and tested their viability. In WP6, the SME partner van Moppes, scaled up the production of functionalized nanodiamonds with the required properties. WP7 then established preclinical assessment of the developed technologies. Under WP8 the dissemination and exploitation of results have been pursued.
Pursuing these goals, HYPERDIAMOND has achieved a set of significant scientific and technological results that extend well beyond the state of the art and has made strong contributions to socio-economic exploitation of its technologies. This includes novel highly optimised polarization sequences for transfer of laser-induced out-of-equilibrium electron spin polarization to surrounding nuclei that are well adapted to experimental constraints. This resulted in the development and demonstration of best-in-class microwave schemes for the NV-based HP of nanodiamonds (NDs)and molecules. Building on this a Diamond Hyperpolarizer capable of polarizing external molecules on a macroscopic scale (100 – 200 nL) working with a nanostructured diamond core has been installed and achieves a world record 12% nuclear spin HP in a diamond via optical polarization using pulsed MW protocols, equivalent to a 100000 fold increase over thermal equilibrium polarisation and exceeding current state of the art by one order of magnitude. The device was designed based on readily available materials only to enable rapid scaling of device. A low-cost permanent magnet fitting the polarisation specifications which is shows better magnetic field homogeneity compared to any commercially available magnet in the same magnetic field range and volume has been produced. Furthermore, first evidence of polarization transfer to 1H spins of external molecules has been obtained. A HP macroscopic diamond was imaged successfully in an MRI.

A crucial new MRI contrast agent are functionalized NDs. HYPERDIAMOND has established high-yield high pressure high temperature synthesis methods of diamond particles with different amounts of 13C ranging from 5% to 37% and have scaled them up to the gram regime. The best reagents for removing 100% of amorphous carbon and graphite from the ND surface to prepare them for functionalisation were identified. Well adapted to this, the surface chemistry for NDs including ultrafast, second time scale, functionalization was developed to enable their use as targeted hyperpolarized-MRI probes. Cellular uptake and biocompatibility of coated fluorescent NDs were established and, as a result, stable bioactive surface coatings are now available and can be customized for the needs of the medical partners.

The synthesis, formulation and characterisation of molecular imaging probes has been put in place. These metabolic probes have been HP with the HyperSense dDNP polarizer and applied to biological systems related to cancer to assess their utility for cancer imaging. The biological systems that have been developed in relation to cancer consist of active oncogenic enzymes (in vitro systems), perfused tissues, such as breast cancer tumors and hepatocellular carcinoma that are kept viable for several hours (ex vivo systems).

The HYPERDIAMOND team was also able to prove the use of PET/MRI for longitudinal monitoring of the in vivo biodistribution of NDs in native and tumor-bearing mice. To this end, the surface of the NDs were functionalized with a chelator for enabling linkage of 68Ga and 89Zr for PET imaging. Accumulation of the labelled NDs was quantified by PET while MRI provided high-resolution anatomical details for determination of the anatomic structures showing accumulation. All required methods for performing the in vivo validation on HP NDs have been successfully established in the project.

Three SMEs have participated in the HYPERDIAMOND project, NVision Imaging Technologies GmbH (production of the Diamond Hyperpolarizer), Van Moppes (ND production), and Lapuntuh/KanFit (Production of custom made permanent magnets). In order to support the path towards commercialization, HYPERDIAMOND established a roadmap for the regulatory process of the Diamond Hyperpolarizer, and performed a market analysis, including market size estimation, customer segmentation, main potential clinical applications and advantages over incumbent technologies.

The Diamond Hyperpolarizer and the ND probe on the basis of functionalized nanoparticles will serve both research and clinical usage that will radically improve the established pyruvate-based metabolic MRI. The fully functional prototype will be the basis of future commercialization of the technology for introducing low-cost, widely accessible metabolic imaging capabilities worldwide.