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A contrast agent is any substance able to enhance the information contained in an image derived from a medical diagnostic instrumentation concerning the traditional or digital radiology entailing the magnetic resonance, nuclear medicine, and last but not least ultrasound (echography). Commercially available ultrasound contrast agents, UCAs, present several drawbacks, as short life-time in the blood circulation and broad distribution of dimension, that limit the quality of the imaging process and do not allow the delivery of drugs. S.I.G.H.T., “Systems forin-situ theranostics using micro-particles triggered by ultra-sound”, is a project focused on the design of multifunctional ultrasound contrast agents as supporting devices for theranostics, i.e. for both diagnostic and therapeutic treatments, in pathologies as thrombosis, tissue repairing and cancer therapies. S.I.G.H.T. will design and develop next-generation UCAs that will represent a breakthrough in the existing panorama of the ultrasound contrast agents because they will allow not only a better imaging for diagnostic purposes but also the non-invasive treatment of high impact pathologies requiring visualization and quick stabilization treatment in emergency conditions, as in the case of the heart stroke, one of the major pathologies in advanced societies. Typical UCAs are gas-filled micro-bubbles with a shell based on phospholipids or denaturated albumin presenting short life-time and short shelf-life.
In this context, S.I.G.H.T. addresses the design of novel multifunctional subsystems, such as targeted micro-balloons and microcapsules for use in medical imaging and delivery. Micro-balloons are gas-filled micro-particles with a biocompatible polymeric shell and, at variance with micro-bubbles, are much more stable and more versatile for anchoring molecules for molecular recognition and drug release. A new feature with respect to the available UCAs, as the tagging the micro-balloon surface, will allow a better localized image of the tissue or organ under investigation and the focal release of drug. The cutting-edge result of these integrated functions is the administration of a much lower drug dosage, avoiding the side effects of pharmaceutical overloading, a well-known drawback of chemotherapy. Microcapsules are the other class of micro-device foreseen in this project as ultrasound contrast agent. In this case the core of the micro-particles contains a liquid or a solid moiety surrounded by a polymer shell. Both the core and the shell can be loaded with different functional molecules for an integrated use of this subdevice for tagging tissue receptors (monitoring and diagnosis) and for drug release (therapeutic treatment).
In particular, micro-balloons,, endowed with a bioengineered surface and capable of targeting specific tissues for molecular imaging quality and ultrasound 3D image reconstruction, will be further functionalised for use as triggered delivery systems for drugs and genes. These integrated devices will be used as echogenic agents in ultrasound diagnostics and biochemical gradient mapping for improving handiness and versatility of healthcare monitoring, with subsequent therapeutic activity, as required.
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