Molecular
imaging is a biomedical research discipline that has
quickly emerged to afford the observation, characterization, monitoring,
and quantification of biomarkers and biological processes in living
organism. It covers a large array of imaging techniques, each of which
provides anatomical, functional, or metabolic information. Multimodality,
as the combination of two or more of these techniques, has proven
to be one of the best options to boost their individual properties,
hence offering unprecedented tools for human health. In this review,
we will focus on the combination of positron emission tomography and
fluorescence imaging from the specific perspective of the chemical
synthesis of dual imaging agents. Based on a detailed analysis of
the literature, this review aims at giving a comprehensive overview
of the chemical strategies implemented to build adequate imaging tools
considering radiohalogens and radiometals as positron emitters, fluorescent
dyes mostly emitting in the NIR window and all types of targeting
vectors.
Anomeric sugar γ‐amino acids efficiently obtained by nucleophilic addition of nitronate anion on sugar olefins are useful building blocks for the preparation of new cyclic glycopeptides. Cyclopeptides have interesting biological properties or find potential applications as templates for anchoring of a wide range of biomolecules or detection dyes. We report here the synthesis of two types of cyclic systems containing γ‐glyco amino acid and α‐amino acid units. A first example was prepared to demonstrate the feasibility of the cyclization of these original structures. To explore the feasibility with more functionalized structures, α‐amino acid and sugar amino‐acid moieties bearing additional functions were chosen as building blocks for the second macrocycle. Furthermore, we describe and explain some unexpected results obtained during deprotection of these new cyclic glycopeptides.
Considering the individual characteristics of positron emission tomography (PET) and optical imaging (OI) in terms of sensitivity, spatial resolution, and tissue penetration, the development of dual imaging agents for bimodal PET/OI imaging is a growing field. A current major breakthrough in this field is the design of monomolecular agent displaying both a radioisotope for PET and a fluorescent dye for OI. We took advantage of the multifunctionalities allowed by a clickable C-glycosyl scaffold to gather the different elements. We describe, for the first time, the synthesis of a cyanine-based dual PET/OI imaging probe based on a versatile synthetic strategy and its direct radiofluorination via [18F]F-C bond formation. The non-radioactive dual imaging probe coupled with two c(RGDfK) peptides was evaluated in vitro and in vivo in fluorescence imaging. The binding on αvβ3 integrin (IC50 = 16 nM) demonstrated the efficiency of the dimeric structure and PEG linkers in maintaining the affinity. In vivo fluorescence imaging of U-87 MG engrafted nude mice showed a high tumor uptake (40- and 100-fold increase for orthotopic and ectopic brain tumors, respectively, compared to healthy brain). In vitro and in vivo evaluations and resection of the ectopic tumor demonstrated the potential of the conjugate in glioblastoma cancer diagnosis and image-guided surgery.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.