Research Highlights

doi:10.1038/nindia.2017.159 Published online 22 December 2017

Watermelon-derived carbon nanodots make efficient optical sensor

Researchers have invented an optical sensor that can detect minute traces of creatinine, a waste product that, when abnormally high in blood and urine, signals ailing kidneys1. This sensor is potentially useful for detecting kidney failure at an early stage.

High levels of creatinine in blood and urine are linked to various diseases including kidney failure. Current methods for detecting creatinine are complex and expensive.

To develop a simple and efficient creatinine sensor, scientists from the Indian Institute of Technology, Madras, and the Indian Institute of Science, Bangalore, led by Mukesh Doble, fabricated an optical sensor by using a nanocomposite made of gold nanoparticles and carbon nanodots prepared from the juice of watermelon pulp.  

The nanocomposite, coated with an animal protein, detected creatinine more efficiently than existing sensors. The nanocomposite easily entered specific mice cells and human cervical cancer cells, and made these cells emit bright green and red light, indicating that the glow came from the nanocomposite.

Results show that the nanocomposite could even be used as a tool for multicolour labelling of bacteria and animal cells. Besides its potential to detect creatinine, the nanocomposite could be used to make light-emitting probes and tools for cellular imaging.


1. Babu, P. J. et al. Synthesis and characterization of biocompatible carbon-gold (C-Au) nanocomposites and their biomedical applications as an optical sensor for creatinine detection and cellular imaging. Sensor. Actuator. B. Chem.(2017) doi:10.1016/j.snb.2017.11.148