Enhanced photoresponsive polyethyleneimine/citric acid co-carbonized dots for facile and selective sensing and intracellular imaging of cobalt ions at physiologic pH

Developing electropositive citric acid–polyethylenimine carbon quantum dots with high biocompatibility and labeling performance for mesenchymal stem cells in vitro and in vivo

“…[36][37][38][39][40] So far, CQDs have been synthesized using CA and PEI as precursors via a hydrothermal method under different conditions. [41][42][43] The performance (including fluorescence properties, surface charge, etc.) of these reported CQDs with CA and PEI as precursors changes with the variation in the synthesis conditions, as the size and surface state of the CQDs are observed to be different when they are synthesized under different conditions.…”

“…of these reported CQDs with CA and PEI as precursors changes with the variation in the synthesis conditions, as the size and surface state of the CQDs are observed to be different when they are synthesized under different conditions. [41][42][43] For example, CQDs synthesized with CA and PEI as precursors via a hydrothermal method at 200 1C for 12 h exhibit good antibacterial and antibiofilm performance. 41 CQDs synthesized using CA and PEI as precursors via a hydrothermal method at 200 1C for 5 h can be used to selectively sense Co 2+ ions.…”

“…41 CQDs synthesized using CA and PEI as precursors via a hydrothermal method at 200 1C for 5 h can be used to selectively sense Co 2+ ions. 42 CQDs synthesized using CA and PEI as precursors via a hydrothermal method at 150 1C for 5 h emit short wavelength light under the excitation of long-wavelength light, referred to as so-called up-conversion photoluminescence. 43 To date, the biocompatibility and labelling performance of positively-charged CQDs synthesized using CA and PEI as precursors towards MSCs in vitro and in vivo have not been reported.…”

Polyethylenimine-Assisted Generation of Optical Nanoprobes for Biosensing Applications

“…Cobalt ions (Co 2+ ) is a crucial biological factor and plays pivotal roles in iron metabolism and hemoglobin biosynthesis, while its abnormal levels in biological systems will cause many diseases . A PEI-CD-based Co 2+ sensing platform was developed by Wang and co-workers by taking advantage of fluorescence quenching effect . The surface amine groups of PEI-CDs could capture Zn 2+ /Cd 2+ to form coordination compounds (Figure c), which showed an enhanced fluorescence emission via inhibiting photoinduced electron transfer pathways.…”

“…97 A PEI-CD-based Co 2+ sensing platform was developed by Wang and co-workers by taking advantage of fluorescence quenching effect. 98 The surface amine groups of PEI-CDs could capture Zn 2+ /Cd 2+ to form coordination compounds (Figure 5c), which showed an enhanced fluorescence emission via inhibiting photoinduced electron transfer pathways. Upon exposure to Co 2+ that interacted with PEI amine groups, the enhanced fluorescence emission of PEI-CDs was quenched through an inner filter effect.…”