New Dioxaborolane Chemistry Enables [¹⁸F]-Positron-Emitting, Fluorescent [¹⁸F]-Multimodality Biomolecule Generation from the Solid Phase

Abstract

New protecting group chemistry is used to greatly simplify imaging probe production. Temperature and organic solvent-sensitive biomolecules are covalently attached to a biotin-bearing dioxaborolane, which facilitates antibody immobilization on a streptavidin-agarose solid-phase support. Treatment with aqueous fluoride triggers fluoride-labeled antibody release from the solid phase, separated from unlabeled antibody, and creates [18F]-trifluoroborate-antibody for positron emission tomography and near-infrared fluorescent (PET/NIRF) multimodality imaging. This dioxaborolane-fluoride reaction is bioorthogonal, does not inhibit antigen binding, and increases [18F]-specific activity relative to solution-based radiosyntheses. Two applications are investigated: an anti-epithelial cell adhesion molecule (EpCAM) monoclonal antibody (mAb) that labels prostate tumors and Cetuximab, an anti-epidermal growth factor receptor (EGFR) mAb (FDA approved) that labels lung adenocarcinoma tumors. Colocalized, tumor-specific NIRF and PET imaging confirm utility of the new technology. The described chemistry should allow labeling of many commercial systems, diabodies, nanoparticles, and small molecules for dual modality imaging of many diseases.

Site-selective installation of BASHY fluorescent dyes to Annexin V for targeted detection of apoptotic cells

“…This strategy that has been successfully demonstrated for the labelling of Annexin V and detection of apoptotic cells may find broader utility when applied to protein biomarkers that are sensitive and loose their activity when randomly conjugated. Additionally, and as a future application, the reported combined synthesis and protein site-selective labelling using BASHY dyes, can be particularly useful for multimodality imaging applications,28–30 since the BASHY core can act itself as an optimal imaging agent while allowing attachment of probes used in other imaging modalities (e.g., magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) or positron emission tomography (PET)).…”

A Murine Model for Quantitative, Real-Time Evaluation of Convection-Enhanced Delivery (RT-CED) Using an 18[F]-Positron Emitting, Fluorescent Derivative of Dasatinib

“…This allows [ 19 F]- 1 to be used in-vitro , without hazard, in the fluorescence-only mode in cellular assays (supplementary figures 1, 4, 6, 7–10) and confirmative multimodality imaging (34). …”

Recent developments in multimodality fluorescence imaging probes

“…It has been difficult to control the exact number of chelating groups and fluorophore molecules in a single antibody molecule in molar ratios, as shown in the top-left structure in Fig. 14 84 , 85 , 86 . In an alternative approach, the ratio of the fluorescence reporting group to the PET tracer was fixed to 1:1 by first linking the OFI reporting group and PET tracer together, and then attaching to the antibody through a single conjugation step, as shown in the top-right structure in Fig.…”