Ratiometric Fluorescence Sensing of Cu(II): Elucidation of FRET Mechanism and Bio‐Imaging Application

Abstract

Rhodamine‐formylaniline conjugate RFA has been developed as a Cu2+‐selective ratiometric fluorescent probe. The probe shows high selectivity towards Cu2+ ion through both its absorption and emission properties; and has been characterized by 1H NMR, FTIR, ESI‐MS spectroscopy. Sensing of Cu2+ proceed through FRET process which is nicely depicted from steady‐state and fluorescence lifetime studies. From the measurement of fluorescence lifetime, the FRET mechanism has been established undoubtedly. The important parameters regarding FRET, namely the energy transfer efficiency (ΦEt) and the Förster distance (R0) have also been calculated by fluorescence measurement. The origin of different emission bands has been distinguished by recording excitation spectra. The lowest detection limit (DL) for Cu2+ ion was 4.2 ×10−7 M in Tris‐HCl buffered MeCN: H2O (10 mM, 1:1 v/v).

PAA Modified Upconversion Nanoparticles for Highly Selective and Sensitive Detection of Cu2+ Ions

“…The deficiency of Cu 2+ could cause anemia, coronary heart diseases, and bone abnormalities (Fu et al, 2019 ). Simultaneously, the excess Cu 2+ can initiate oxidative stress, leading to neurodegenerative diseases such as Menkes syndrome, Indian childhood cirrhosis, and Wilson's, Alzheimer's, Parkinson's, and prion diseases (Vishal Desai, 2008 ; Chen P. et al, 2016 ; Sikdar et al, 2018 ). Excessive Cu 2+ consumption could cause kidney/liver damage, amyotrophic lateral sclerosis, and vomiting (Sikdar et al, 2018 ).…”

“…Simultaneously, the excess Cu 2+ can initiate oxidative stress, leading to neurodegenerative diseases such as Menkes syndrome, Indian childhood cirrhosis, and Wilson's, Alzheimer's, Parkinson's, and prion diseases (Vishal Desai, 2008 ; Chen P. et al, 2016 ; Sikdar et al, 2018 ). Excessive Cu 2+ consumption could cause kidney/liver damage, amyotrophic lateral sclerosis, and vomiting (Sikdar et al, 2018 ). On the other hand, Cu 2+ generated as industrial waste is responsible for the marine environment pollution, thereby contaminating marine organisms, ultimately affecting human health through poisoning if the polluted marine organisms are consumed (Fu et al, 2019 ).…”

“…These organic fluorescent probes absorb high energy UV/blue light, which resulted in low detectability due to the background fluorescence interference and shallow penetration depth (Jiang and Meng, 2013 ; Ostad et al, 2017 ). The nominal concentration of the Cu 2+ in blood and drinking water allowed by the U.S. Environmental Protection Agency (EPA) is around 100–150 μg/dL (15.7–23.6 μM) and 1.3 ppm (~20 μM), respectively (Helal et al, 2011 ; Jiang and Meng, 2013 ; Sikdar et al, 2018 ). Similarly, the World Health Organization (WHO) has announced that the oral intake of Cu 2+ could not exceed more than a few milligrams (2 or 3 mg/day) in adults (Fu et al, 2019 ).…”

“…Among these elements, the copper (Cu 2+ ), being the third most essential and abundant micronutrient, exists in very low concentration and participates in various organism's physiological processes (Becker et al, 2005;Sikdar et al, 2018). Mostly, Cu 2+ resides in the brain, particularly in basal ganglia, hippocampus, cerebellum, and numerous synaptic membranes (Vishal Desai, 2008).…”

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“…The deficiency of Cu 2+ could cause anemia, coronary heart diseases, and bone abnormalities (Fu et al, 2019). Simultaneously, the excess Cu 2+ can initiate oxidative stress, leading to neurodegenerative diseases such as Menkes syndrome, Indian childhood cirrhosis, and Wilson's, Alzheimer's, Parkinson's, and prion diseases (Vishal Desai, 2008;Chen P. et al, 2016;Sikdar et al, 2018). Excessive Cu 2+ consumption could cause kidney/liver damage, amyotrophic lateral sclerosis, and vomiting (Sikdar et al, 2018).…”