Molecular imaging and nanobiotechnologies

• Dr. Alessandro Amaolo PhD Student in “Pharmaceutical and Biomolecular 
  Sciences”, University of Torino
• Dr. Chiara Papi PhD Student in “Innovation in the diagnosis, prevention and 
  therapy of infections at epidemic-pandemic risk”, University of Siena
• Dr. Chiara Romiti PhD “Student in Innovation in the diagnosis, prevention and 
  therapy of infections at epidemic-pandemic risk”, University of Siena
• Dr. Angelo Scarciglia PhD Student in “Legal and Strategic Studies for innovation 
  in defense and security”, Centro Alti Studi per la Difesa (CASA), University of Roma

Our research deals with the merge of molecular imaging and nanobiotechnologies, at the cross between biotechnological and chemical sciences. We focus on the 3 research activities: 
Design and development of innovative and “smart” nano systems for: 
→ in vivo diagnosis (imaging) and targeted therapy. 
→ in vitro assays for quantification of bioanalytes. 
→ detection and decontamination from chemical and biological weapons of mass destruction (CBNRe). 
In vivo imaging of oncological, neurological (multiple sclerosis) and infectious diseases in preclinical murine models by Magnetic Resonance Imaging (MRI), Optical Imaging (OI) and Photoacoustic Imaging (PAI): 
→ analysis of tumour microenvironment (pH, vascularization, hypoxia…). 
→ analysis of water exchange across cells’ membranes. 
→ design of innovative metal-based imaging contrast agents. 
Design of new strategies for reducing environmental impact of Gd-based MRI contrast agents. Synthesis and the characterization of nano-/micro-systems are under investigation for the decontamination from heavy metals and water contaminants. The three main research fields have strong interconnections. In fact, nanosystems are also used as imaging agents and in vivo imaging is used for monitoring nanosystems' distribution in vivo (Fig1).

A significant application of imaging relies on the possibility to have multiparametric MR imaging, i.e. the simultaneous quantification of different hallmarks of the disease. In particular, we focused on the assessment of i) tumour size, ii) protein content, iii) water freedom degree, iv) extracellular / extravascular pH, v) vascular volume and vi) hypoxia (Fig.2).

Figure 3. CEST-MRI maps of water permeability in breast cancers at different phenotypes. Finally, another research field relies on “In vivo imaging of oncological, neurological (multiple sclerosis) and infectious diseases in preclinical murine models by Magnetic Resonance Imaging (MRI), Optical Imaging (OI) and Photoacoustic Imaging (PAI)”. In vivo imaging techniques have revolutionised the ability to study and understand the complexities of oncological, neurological, and infectious diseases in preclinical murine models. These techniques provide insights into the tumour microenvironment, water exchange across cell membranes, and the development of innovative metal-based imaging contrast agents, ultimately advancing our knowledge and potential treatment strategies for these diseases.

These last two parameters were assessed upon in vivo injection of ex vivo RBCs labelled with proper Gd-complexes. The Gd-labelled- RBCs can provide quantitative maps of vascular volume (Ferrauto G, et al. S. Biomaterials. 2015) and of hypoxia (Di Gregorio E, et al. ACS Nano. 2015). These Gd-RBCs appeared to be stable and biocompatible, suitable for in vivo applications. As far as concern the measurement of the extracellular / extravascular pH, several attempts have been carried out by our group, obtaining especially results using YbHPDO3A as pH responsive probe, translable for preclinical applications. With this MRI probe, we were able to measure pH of melanoma and glioblastoma in murine models (Delli Castelli D., Ferrauto G. et al. Magn Reson Med 2014; Ferrauto G, et al. NMR Biomed. 2018). Another topic of great interest is the quantitative analysis of water exchange across cells’ membranes, e.g. across cancer cells. Recently, we deposited a patent and published a paper (Di Gregorio E. et al. Angewandte Chemie In. Ed.) reporting an innovative in vivo imaging approach to quantify water cycling across the membrane through transporters (Fig.3).

It can be considered a hallmark of cellular metabolism, of high diagnostic relevance in the characterization of tumours and other diseases. The method relies on the response of intracellular proton exchanging molecules to the presence of extracellular Gdbased contrast agents (GBCAs). The effect is detected at the MRI-CEST (Magnetic Resonance Imaging - Chemical Exchange Saturation Transfer) signal of intracellular proton exchanging molecules. The method has been tested on RBC and on orthotopic murine models of breast cancer with different degree of malignancy (4T1, TS/A and 168FARN) and it allows obtaining high resolution and quantitative maps of membrane permeability. Water membrane permeability was correlated to the cells’ aggressiveness. Moreover, it can act as an early reporter to monitor therapeutic