Bioconjugation of a Near-Infrared DNA-Stabilized Silver Nanocluster to Peptides and Human Insulin by Copper-Free Click Chemistry

• DOI: 10.1021/jacs.3c04768
• Publication Date: 2023-07-13T20:54:10Z
• Authors: Vanessa Rück; Narendra K. Mishra; Kasper K. Sørensen; Mikkel B. Liisberg; Ane B. Sloth; Cecilia Cerretani; Christian B. Moll...; Andreas Kjaer; Chenguang Lou; Knud J. Jensen; Tom Vosch
• Keywords: Silver; Spectrometry; Metal Nanoparticles/chemistry; Silver/chemistry; Metal Nanoparticles; CHO Cells; DNA; Fluorescence; Cricetulus; Spectrometry, Fluorescence; Cricetinae; Humans; Animals; Insulin; Click Chemistry; Peptides; DNA/chemistry

DNA-stabilized silver nanoclusters (DNA-AgNCs) are biocompatible emitters with intriguing properties. However, they have not been extensively used for bioimaging applications due to the lack of structural information and hence predictable conjugation strategies. Here, a copper-free click chemistry method for linking a well-characterized DNA-AgNC to molecules of interest is presented. Three different peptides and a small protein, human insulin, were tested as labeling targets. The conjugation to the target compounds was verified by MS, HPLC, and time-resolved anisotropy measurements. Moreover, the spectroscopic properties of DNA-AgNCs were found to be unaffected by the linking reactions. For DNA-AgNC-conjugated human insulin, fluorescence imaging studies were performed on Chinese hamster ovary (CHO) cells overexpressing human insulin receptor B (hIR-B). The specific staining of the CHO cell membranes demonstrates that DNA-AgNCs are great candidates for bioimaging applications, and the proposed linking strategy is easy to implement when the DNA-AgNC structure is known.