Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds

The synthesis of graphene oxide (GO) using green precursors has garnered significant attention due to its efficiency in various applications. Herein, we have synthesized red fluorescent graphene quantum dots (RGQDs) using GO and a bio-precursor, Alstonia scholaris (AS) leaf extract, as capping and s...

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Main Authors: Rachita Newar, Nasrin Sultana, Kalpajit Dutta, Hemen Sarma, Arabinda Baruah
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Next Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2949822825005131
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author Rachita Newar
Nasrin Sultana
Kalpajit Dutta
Hemen Sarma
Arabinda Baruah
author_facet Rachita Newar
Nasrin Sultana
Kalpajit Dutta
Hemen Sarma
Arabinda Baruah
author_sort Rachita Newar
collection DOAJ
description The synthesis of graphene oxide (GO) using green precursors has garnered significant attention due to its efficiency in various applications. Herein, we have synthesized red fluorescent graphene quantum dots (RGQDs) using GO and a bio-precursor, Alstonia scholaris (AS) leaf extract, as capping and stabilizing agents. AS leaves are rich in polyphenols, which can serve as an effective bio-reagent for the synthesis of RGQDs. For the synthesis of RGQDs, we have adopted a simple hydrothermal approach. After the successful synthesis of the material, we developed a fluorometric and electrical sensing platform for detecting picric acid (PA) and para-nitrophenol (PnPh). Both PA and PnPh are hazardous environmental pollutants. The RGQDs exhibited exceptional sensitivity and selectivity towards PA and PnPh, with optical sensing limits of 0.288 µM and 0.322 µM, respectively. Additionally, a biodegradable and cost-effective electrical sensor was also fabricated for detecting the same, achieving a lower detection limit of 1.17 µM and 0.71 µM for PA and PnPh, respectively, which exemplifies the superior analytical precision and sensitivity of the sensor. In addition to developing the sensing platforms, we investigated the antibacterial activity of RGQDs against both Staphylococcus aureus (a Gram-positive bacterium) and Escherichia coli (a Gram-negative bacterium). Antibacterial activity was evaluated through standard microbiological analysis, including minimum inhibitory concentration (MIC) measurements. The MIC estimations against S. aureus and E. coli are 24.76 ± 1.53 µg/mL-1 and 21.966 ± 1.104 µg/mL-1, respectively. The RGQDs demonstrated potent antibacterial effects, with significant growth inhibition capacity for both bacterial strains. In summary, this work presents a novel method for synthesizing RGQDs with dual-mode detection capabilities and significant antibacterial properties.
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spelling doaj-art-edb9e06ddbcd43c1aa65a2398fb3958e2025-08-20T03:56:04ZengElsevierNext Materials2949-82282025-10-01910099510.1016/j.nxmate.2025.100995Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compoundsRachita Newar0Nasrin Sultana1Kalpajit Dutta2Hemen Sarma3Arabinda Baruah4Department of Chemistry, Gauhati University, Guwahati, Assam 781014, IndiaAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; Institute of Advanced Study in Science and Technology, Guwahati, Assam 781035, IndiaDepartment of Bio-engineering and Technology, Laboratory of Molecular Virology and Oncology Gauhati University, Guwahati, Assam 781014, IndiaDepartment of Botany, Bodoland University, Assam 783370, India; Corresponding authors.Department of Chemistry, Gauhati University, Guwahati, Assam 781014, India; Corresponding authors.The synthesis of graphene oxide (GO) using green precursors has garnered significant attention due to its efficiency in various applications. Herein, we have synthesized red fluorescent graphene quantum dots (RGQDs) using GO and a bio-precursor, Alstonia scholaris (AS) leaf extract, as capping and stabilizing agents. AS leaves are rich in polyphenols, which can serve as an effective bio-reagent for the synthesis of RGQDs. For the synthesis of RGQDs, we have adopted a simple hydrothermal approach. After the successful synthesis of the material, we developed a fluorometric and electrical sensing platform for detecting picric acid (PA) and para-nitrophenol (PnPh). Both PA and PnPh are hazardous environmental pollutants. The RGQDs exhibited exceptional sensitivity and selectivity towards PA and PnPh, with optical sensing limits of 0.288 µM and 0.322 µM, respectively. Additionally, a biodegradable and cost-effective electrical sensor was also fabricated for detecting the same, achieving a lower detection limit of 1.17 µM and 0.71 µM for PA and PnPh, respectively, which exemplifies the superior analytical precision and sensitivity of the sensor. In addition to developing the sensing platforms, we investigated the antibacterial activity of RGQDs against both Staphylococcus aureus (a Gram-positive bacterium) and Escherichia coli (a Gram-negative bacterium). Antibacterial activity was evaluated through standard microbiological analysis, including minimum inhibitory concentration (MIC) measurements. The MIC estimations against S. aureus and E. coli are 24.76 ± 1.53 µg/mL-1 and 21.966 ± 1.104 µg/mL-1, respectively. The RGQDs demonstrated potent antibacterial effects, with significant growth inhibition capacity for both bacterial strains. In summary, this work presents a novel method for synthesizing RGQDs with dual-mode detection capabilities and significant antibacterial properties.http://www.sciencedirect.com/science/article/pii/S2949822825005131RGQDsLODOptical sensingElectrical sensingPrototype devicePicric acid
spellingShingle Rachita Newar
Nasrin Sultana
Kalpajit Dutta
Hemen Sarma
Arabinda Baruah
Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds
Next Materials
RGQDs
LOD
Optical sensing
Electrical sensing
Prototype device
Picric acid
title Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds
title_full Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds
title_fullStr Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds
title_full_unstemmed Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds
title_short Eco-friendly synthesis of red fluorescent graphene quantum dots from Alstonia scholaris for optoelectronic detection of nitroaromatic compounds
title_sort eco friendly synthesis of red fluorescent graphene quantum dots from alstonia scholaris for optoelectronic detection of nitroaromatic compounds
topic RGQDs
LOD
Optical sensing
Electrical sensing
Prototype device
Picric acid
url http://www.sciencedirect.com/science/article/pii/S2949822825005131
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