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Food adulteration is an alarming concern in developing countries causing an increased rate of cancer incidents. This study aims to address this concern by detecting adulteration in green vegetables. A facile green one-step and cost-effective strategy to synthesize carbon quantum dots derived from a herbal source has been utilized to design a fluorescence-based sensor for detecting malachite green (MG), a toxic carcinogenic dye, commonly used as an adulterant to give a fresh green look to green vegetables. The leaf-extract of Ocimum tenuiflorum has been used to synthesize highly photostable carbon dots for detecting MG with a limit of detection (LOD) as low as 18 nM. Further, this principle has been utilized to design a prototype calorimetric sensor. The mechanism of the interaction between malachite green and carbon dots has been probed using DFT by employing the SMD solvation model. In addition, CQDs also possess strong antioxidant activity and minimal cytotoxicity enabling their utilization in many biological and sensing applications. This shows the versatility of these easily scalable carbon dots.

Carbon quantum dots derived from banana leaves by a simple hydrothermal process has been used as an electron transport layer to fabricate Organic Light Emitting Diodes. To the best of our knowledge, this is the first report of Carbon QD utilized as an electron transport layer inOLED. Devices with multilayered structureITO/PEDOT: PSS/PFO/CQD/LiF/Al are fabricated on indium tin oxide (ITO) coated glass substrates. Current-Voltage (IÀ V) curves reveal that the turn-on voltages are reduced from 8 V to 6 V as compared with pristine PFO device.Results show CQD as an ETL has enhanced the performance and efficiency of the OLEDs.[a] Md.

Arjuna terminalia-derived Carbon Quantum Dots synthesized by hydrothermal method are utilized to investigate the effect of their reaction parameters on the synthesis and growth of gold nanoparticles. In this study, carbon dots are synthesized at two temperatures (160°C and 200°C) and two solvents (water and ethanol) to investigate the effect of four variants on the formation of non-cytotoxic gold nanoparticles. They are extensively characterized to understand their different physical and chemical properties. Gold nanoparticles synthesized using ethanol based carbon dots show greater stability. Addition of Type-I collagen stabilizes the gold nanoparticles to form gold nanoparticle-coated collagen fibrils. Further, β-mercaptoethanol initiates a spontaneous precipitation and sedimentation of visible gold micelles similar to "snowing". This work may help in future to understand the reduction of chloroauric acid using bio-derived plant extracts, microbial consortium and very recently, carbon quantum dots, for specific tailoring of gold nanoparticles for biomedical, surface-enhanced Raman spectroscopy and theranostics applications.

Collagen-mimetic peptides have been utilized to form structures of different morphology for various biomedical and nanotechnology applications. This chapter describes the characterization of collagen-mimetic peptide self-assembled structures formed by tuning the interactions between peptides. Inclusion of varying hydrophobicity, electrostatic forces, and stereoselectivity was mainly employed in CMP designs discussed herein. The role of these forces can be assessed using multiple characterization techniques. Light scattering techniques have been employed to study the aggregation kinetics of self-assembled nanostructures and to investigate the net charge distribution of peptides. Spectroscopy techniques like circular dichroism, fluorescence, and absorption spectroscopy have been utilized to decipher the secondary structures of peptide and binding of the peptides with dyes. Imaging techniques helped in resolving the morphology of the self-assembled structures. Confocal fluorescence microscopy and differential scanning calorimetry helped in indirect assessment of hydrophobicity and X-ray studies to determine the inter-helical spacing between the triple helical peptides of the higher order structures.