MOF as a fluorometric sensor of dopamine

The deficiency of dopamine in the human body can cause depression, lack of concentration, Alzheimer’s disease, schizophrenia and Parkinson’s disease. In contrast, the high concentration of dopamine is also harmful to our body. Excess dopamine secretion can cause rapid heart rate, hypertension, delusions, hallucinations and heart failure. Therefore, the quantitative and qualitative sensing of dopamine in various body fluids is urgently required for the critical diagnosis of these deadly diseases.

To develop a simple and efficient method for the detection of dopamine, Prof. Dhakshinamoorthy has developed a method using boronic acid functionalized Al-based metal organic frameworks (MOFs), CAU-10 MOF for the recognition of dopamine. This developed sensor works with the principle of attacking the –OH groups of dopamine to the vacant π-orbital of B atom of the boronic acid groups available in MOFs. The pushing of the electron density towards the boron atom can exhibit turn-on fluorescence sensing with the detection of dopamine with high sensitivity limit of detection (LOD) as 3.5 nM. Indeed, turn-on sensing was observed when dopamine solution was injected into the dispersion of the MOF in water.

 

In this way, they develop appropriate and reliable detection tool for dopamine is still beyond the reach of modern pharmaceutical researchers. Interestingly, this solid is not only able to detect dopamine in aqueous medium but also has the ability to detect dopamine in real samples like human blood serum and urine samples. Furthermore, a cost-effective sensor paper strip was developed for the rapid and on-site detection of this neurotransmitter.

Comparing their results with other sensors reported from the literature, the present CAU-10-based MOF fluorescent probe that can detect dopamine discriminatively via a switch-on mechanism with great efficiency. Moreover, the obtained LOD value of 3.5 nM with the response time <1 min for the recognition of dopamine are the lowest among the previously reported sensors of dopamine.

Furthermore, the catalytic activity of the material was checked for the Biginelli condensation reaction of benzaldehyde, ethylacetoacetate and urea towards the synthesis of dihydropyrimidinones in moderate to high yields (39-94%). The functionalized MOF exhibited remarkable activity and recyclability towards the catalytic reaction.

Reference

Two birds with one arrow: a functionalized Al(iii) MOF acts as a fluorometric sensor of dopamine in bio-fluids and a recyclable catalyst for the Biginelli reaction. Ghosh, Subhrajyoti; Nagarjun, Nagarathinam; Nandi, Soutick; Dhakshinamoorthy, Amarajothi; Biswas, Shyam; 2022, 6717, 6727 Journal of Materials Chemistry C http://dx.doi.org/10.1039/D2TC00022A