Site-specific modification of biomolecules is crucial to the development of functional constructs for biomedical applications,offering precise control over the number and location of the functional handles incorporate...Site-specific modification of biomolecules is crucial to the development of functional constructs for biomedical applications,offering precise control over the number and location of the functional handles incorporated.In this work,we designed,synthesised and characterised three luminescent cyclometallated iridium(Ⅲ)complexes bearing a 2-cyanobenzothiazole(CBT)moiety[Ir(N^C)₂(bpy-CBT)](PF₆)(HN^C=2-(2,4-difluorophenyl)pyridine(Hdfppy)(1),2-phenylpyridine(Hppy)(2),methyl 2-phenyl-4-quinolinecarboxylate(Hpqe)(3);bpy-CBT=4-(2-cyanobenzo[d]thiazol-6-yl)oxymethyl-4’-methyl-2,2’-bipyridine)as site-specific labels for N-terminal cysteine(NCys).These complexes displayed high reactivity and selectivity towards NCys,enabling facile peptide conjugation via the CBT–NCys condensation reaction.Complex 2 was used to prepare a peptide-based phosphorogenic probe 2-MMP-QSY7 for matrix metalloproteinase-2/9(MMP-2/9)activity sensing and photocytotoxic applications.The conjugate showed substantial emission enhancement(I/Io=9.8)in the presence of MMP-2/9,which allowed for the sensitive detection of MMP-2/9 activity in live cells and the facile differentiation of cancer and normal cells.The conjugate also exhibited controllable singlet oxygen generation and thereby photocytotoxicity in these cell lines.Additionally,complex 2 was utilised to fabricate two types of hydrogels:a non-biodegradable hydrogel Gel-1 as a cell culture scaffold integrated with MMP-2/9 sensing capability for examining the enzyme activity in 3D cell culture;and a biodegradable hydrogel Gel-2 as an MMP-2/9-sensitive carrier for selective delivery of luminescent iridium(Ⅲ)complexes into cancer cells for imaging and photocytotoxic applications.The results of this work will contribute to the development of site-specific bioconjugation reagents with interesting photophysical properties,facilitating the construction of photofunctional peptide conjugates and biomaterials for biosensing,bioimaging,phototherapy and drug delivery applications.展开更多
基金the Hong Kong Research Grants Council(Project No.CityU 11301121,CityU 11317022,CityU 11309423 and C7075-21GF)the Hong Kong Research Grants Council and National Natural Science Foundation of China(Project No.N_CityU104/21).
文摘Site-specific modification of biomolecules is crucial to the development of functional constructs for biomedical applications,offering precise control over the number and location of the functional handles incorporated.In this work,we designed,synthesised and characterised three luminescent cyclometallated iridium(Ⅲ)complexes bearing a 2-cyanobenzothiazole(CBT)moiety[Ir(N^C)₂(bpy-CBT)](PF₆)(HN^C=2-(2,4-difluorophenyl)pyridine(Hdfppy)(1),2-phenylpyridine(Hppy)(2),methyl 2-phenyl-4-quinolinecarboxylate(Hpqe)(3);bpy-CBT=4-(2-cyanobenzo[d]thiazol-6-yl)oxymethyl-4’-methyl-2,2’-bipyridine)as site-specific labels for N-terminal cysteine(NCys).These complexes displayed high reactivity and selectivity towards NCys,enabling facile peptide conjugation via the CBT–NCys condensation reaction.Complex 2 was used to prepare a peptide-based phosphorogenic probe 2-MMP-QSY7 for matrix metalloproteinase-2/9(MMP-2/9)activity sensing and photocytotoxic applications.The conjugate showed substantial emission enhancement(I/Io=9.8)in the presence of MMP-2/9,which allowed for the sensitive detection of MMP-2/9 activity in live cells and the facile differentiation of cancer and normal cells.The conjugate also exhibited controllable singlet oxygen generation and thereby photocytotoxicity in these cell lines.Additionally,complex 2 was utilised to fabricate two types of hydrogels:a non-biodegradable hydrogel Gel-1 as a cell culture scaffold integrated with MMP-2/9 sensing capability for examining the enzyme activity in 3D cell culture;and a biodegradable hydrogel Gel-2 as an MMP-2/9-sensitive carrier for selective delivery of luminescent iridium(Ⅲ)complexes into cancer cells for imaging and photocytotoxic applications.The results of this work will contribute to the development of site-specific bioconjugation reagents with interesting photophysical properties,facilitating the construction of photofunctional peptide conjugates and biomaterials for biosensing,bioimaging,phototherapy and drug delivery applications.
