Highly efficient method for 125I-radiolabeling of biomolecules using inverse-electron-demand Diels–Alder reaction

Radioanalytical Techniques to Quantitatively Assess the Biological Uptake and In Vivo Behavior of Hazardous Substances

“…In general, the labeling procedure of radioactive iodine is significantly simpler than that of 14 C labeling. However, it is often difficult to accurately quantify 125 I-labeled analogs in animal models due to the low in vivo stability of the C-I bond and high accumulation of radioactive iodine in the thyroid [ 56 , 57 , 58 , 59 , 60 ].…”

Prosthetic groups for radioiodination and astatination of peptides and proteins: A comparative study of five potential bioorthogonal labeling strategies

“…Click ligation of radioactive tags on various biomolecules are also the object of an important research effort to provide new strategies for labeling with radioisotopes that require fast, simple and efficient procedures that are difficult to reach by conventional chemistry. 12 Recent reports have proposed the use of bioorthogonal chemistry for radioiodination of peptides or proteins with clickable prosthetic groups including the strain-promoted alkyneazide cycloaddition (SPAAC) 13,14 and the inverse electron demand Diels Alder cycloaddition (IEDDA) reactions, 15,16 but to our knowledge, such strategy has not yet been reported for astatination. Yet, the necessity of fast, simple and quantitative yielding labeling procedure is even more essential for astatination with 211 At because of its availability in low amounts, its shorter physical half-life compared to relevant iodine radioisotopes, and the marked radiolysis issues due to the astatine decay limiting the starting activity that can be engaged in a radiolabeling procedure, 17 for the preparation of radiopharmaceuticals for clinical use, or even for animal studies.…”

Efficient and Site-Specific 125I-Radioiodination of Bioactive Molecules Using Oxidative Condensation Reaction

“… 16 Recently, conventional bioconjugation methods including radioiodinated azide–alkyne cycloaddition, 20 Staudinger–Bertozzi ligation, 21 and inverse electron-demand Diels–Alder ligation between trans-cyclooctene (TCO)-conjugated biomolecules and radioiodinated tetrazine were utilized for radioiodination. 22 The bioconjugation reactions based on azide–alkyne cycloaddition and Staudinger–Bertozzi ligation demonstrated slow reaction kinetics. The reaction between TCO and radioiodinated tetrazine is fast but it provides a mixture of radioiodinated products, which may not be acceptable to regulatory authorities for clinical application.…”

“…The reaction between TCO and radioiodinated tetrazine is fast but it provides a mixture of radioiodinated products, which may not be acceptable to regulatory authorities for clinical application. 22 Therefore, the search for more efficient, easy to apply, and clean bioconjugation reactions is still in demand to satisfy diverse applications. Moreover, expansion can provide additional and better choices when multiple reactions are used to modify the biomolecules.…”

“…The cRGD peptide and human serum albumin (HSA) protein were used as the model substrates. 22 The biodistribution data for radioiodinated HSA have been acquired to confirm the in vivo stability against deiodination. Among the various available radioiodine, 125 I has been selected because of its easy commercial availability and suitable half-life (59.4 days), which allows repetitive experiments to optimize the radiolabeling procedure.…”