Chemistry Department, RCSI, 123 St. Stephen's Green, Dublin, 2, Ireland.
Chemistry. 2022 Feb 19;28(11):e202104111. doi: 10.1002/chem.202104111. Epub 2022 Jan 28.
The importance of bioconjugation reactions continues to grow for cell specific targeting and dual therapeutic plus diagnostic medical applications. This necessitates the development of new bioconjugation chemistries, in-flow synthetic and analytical methods. With this goal, continuous flow bioconjugations were readily achieved with short residence times for strained alkyne substituted carbohydrate and therapeutic peptide biomolecules in reaction with azide and tetrazine substituted fluorophores. The strained alkyne substrates included substituted 2-amino-2-deoxy-α-D-glucopyranose, and the linear and cyclic peptide sequences QIRQQPRDPPTETLELEVSPDPAS-OH and c(RGDfK) respectively. The catalyst and reagent-free inverse electron demand tetrazine cycloadditions proved more favourable than the azide 1,3-dipolar cycloadditions. Reaction completion was achieved with residence times of 5 min at 40 °C for tetrazine versus 10 min at 80 °C for azide cycloadditions. The use of a fluorogenic tetrazine fluorophore, in a glass channelled reactor chip, allowed for intra-chip reaction monitoring by recording fluorescence intensities at various positions throughout the chip. As the Diels-Alder reactions proceeded through the chip, the fluorescence intensity increased accordingly in real-time. The application of continuous flow fluorogenic bioconjugations could offer an efficient translational access to theranostic agents.
生物共轭反应对于细胞特异性靶向和双重治疗加诊断医学应用的重要性不断增加。这需要开发新的生物共轭化学、流动合成和分析方法。为此，带有张力炔取代的碳水化合物和治疗肽生物分子的连续流生物共轭反应很容易实现，且停留时间短，与叠氮化物和四嗪取代的荧光团反应。张力炔底物包括取代的 2-氨基-2-脱氧-α-D-吡喃葡萄糖、线性和环状肽序列 QIRQQPRDPPTETLELEVSPDPAS-OH 和 c（RGDfK）。无催化剂和试剂的逆电子需求四嗪环加成比叠氮化物 1,3-偶极环加成更有利。在 40°C 下，四嗪的反应完成时间为 5 分钟，而叠氮化物的反应完成时间为 80°C 时为 10 分钟。在玻璃通道反应器芯片中使用荧光性四嗪荧光团，可以通过在芯片各处记录荧光强度来进行芯片内反应监测。随着 Diels-Alder 反应在芯片中进行，荧光强度相应地实时增加。连续流动荧光生物共轭反应的应用可能为治疗药物提供有效的转化途径。
