Using an environmentally friendly process, Pakistani scientists have produced fluorescent nanoparticles from used tea. Nanoparticles can be used as sensors in a variety of medical applications.
Umber Abbas: A PhD researcher at the University of Newcastle in the UK and others from the University of Oxford in the UK discovered the tea bag. The team worked by converting used tea bags into graphene quantum dots (GQDs). They have designed a highly selective sensor to detect iron in drinking water and in Parkinson’s patients.
Additionally, graphene, an allotrope of carbon discovered in 2004, is made of tiny particles. Graphene is a mixture of sheets of carbon atoms that you can easily assemble from a piece of graphite using adhesive tape.
In addition, the Nobel Prize was awarded for the discovery of this magical substance. Therefore, graphene is an excellent material for new research in medicine, material science and other fields.
On the other hand, researchers and scientists around the world are constantly busy fine-tuning graphene for optimum results. For example, in March 2018, Pablo Jarrillo-Herrero at the Massachusetts Institute of Technology (MIT) discovered that when one atom-thick graphene sheet is placed on top of another with a slight twist, the material exhibits superconductivity.
Likewise, the same goes with flourscenes in GQDs gave the team a clue to do some more tweaks.
Though, the team intended to glow the particles, there is no energy or bandgap in Graphene. However, Abbas and his team successfully attempted a different approach to this issue.
Amber Abbas told the news, ‘One of the challenges with Graphene is zero bandgaps that limit its optical emission and applications in flourscenes field. To this end, I tried to solve this challenge by cutting the Graphene sheet into small pieces and introducing a band gap. As a result, small pieces of Graphene started fluorescing’.
In addition, he also said that our main aim was to develop budget-friendly advanced material. Therefore, we started using a waste black tea bag.
Recipe of Graphene Quantum Dots
The recipe behind the whole process was to first convert the black tea waste into black char by heat treatment at 500°C. The resulting char was further through the high-pressure off vessel at 200-250°C in the presence of Oxone chemical. Later, the mixture is used to filter and remove the tiny particles of Graphene after the reaction.
The nanosized Graphene sheets in the filtrate liquid began to fluoresce. The dots now can emit fluorescences, indicating that a bandgap has formed in the material. As a result, the team was able to transform the GQDs into an effective sensing material.
In the next step, researchers worked on nanodot structure, size, quality and other characteristics by using High Transmission Electron Microscopy.
The Blue Light
The entire process of the experiment shows that a single dot is 1 to 5 nanometres in size with a thickness of one nanometre.
Hence, the GQDs can detect the presence of iron or its states based on their strong luminescent blue color and turn it into a sensor later.
As we know, the abnormal iron buildup in the brain increases cognitive decline and may lead to Alzheimer’s disease.
On the other hand, iron accumulation is also harmful to the environmental system and water.
Furthermore, the particles are in green, acid-free, cost-effective method with raw material which is abundant-the used tea.