Steady-state and time-resolved fluorescence studies on interactions of carbon “quantum” dots with nitrotoluenes

Amine Group Surface-Functionalized Carbon Quantum Dots Exhibit Anti-amyloidogenic Effects Towards Hen Egg White Lysozyme by Inducing Formation of Nontoxic Spherical Aggregates

The tendency of polypeptide chains to deviate from their conventional protein folding pathway and instead get trapped as off-pathway intermediates, has been a matter of great concern. These off-pathway intermediates eventually lead to the formation of insoluble, ordered fibrillar aggregates called amyloids, which are responsible for a host of neurodegenerative diseases like Alzheimer's disease, Parkinson's disease and Type II diabetes. In spite of extensive research, development of an effective therapeutic strategy against amyloidosis still remains elusive. In recent times, carbon quantum dots (CQD) have grabbed the attention of researchers against amyloidogenesis due to their ease of preparation, aqueous soluble nature, unique optical properties, high surface to volume ratio, physio-chemical properties, semi-conducting nature and mainly biocompatible. In the current study, we have reported an easy-to-prepare procedure for synthesis of amine group surface functionalized CQDs from commonly available kitchen spices with anti-oxidant properties. The as-synthesized CQDs were evaluated for their anti-amyloidogenic properties towards Hen Egg White Lysozyme (HEWL). Our results clearly show that the surfaced functionalized CQDs were able to interact with HEWL, thereby forming a stable complex, which was resistant towards amyloid formation and instead lead to the formation of non-toxic globular aggregates.

Structural, morphological, and optical properties of carbon nanoparticles unsheathed from date palm fronds

Several studies have reported the synthesis of carbon nanoparticles (CNPs) by various methods. In this study, an easy one-step process to unsheathe CNPs from date palm fronds through a top-down ball milling method has been reported. The CNPs were characterized using various spectroscopic and microscopic methods to determine their structural and morphological features, optical properties, crystallinity, physicochemical properties, and particle stability. Transmission electron microscopy (TEM) revealed that the obtained CNPs' size ranged from 4 to 22 nm in a crystalline form. Scanning electron microscopy (SEM) confirmed their spherical shape, while the maximum photoluminescence (PL) intensity was recorded at 464 nm when excited at 375 nm. The unsheathed CNPs produced a good quantum yield (QY) of 3.24%. Furthermore, the CNPs exhibited high Raman ratios of I D/I G and I 2D/I G with values of 0.59 and 0.04, respectively, verifying their multilayer crystalline graphitic nature. These Raman ratios also agree with the X-ray diffractometry (XRD) results. The CNPs' sp2 and sp3 carbon bonds were confirmed by X-ray photoelectron spectroscopy (XPS), with oxygen on the surface forming carboxyl and carbonyl groups with no other observable impurities. Furthermore, the extracted CNPs showed excellent PL properties for up- and down-conversion. These properties are exemplary for low-cost biomass with potential applications in biomedicine. Therefore, the extracted CNPs reported in this study have potential applications in optical imaging.

Fluorescence sensing by carbon nanoparticles

Sensing is one of the most important fields in which chemists, engineers and other scientists are involved to realize sensoristic devices that can detect different analytes, both chemicals and biologicals. In this context, fluorescence sensing paves the way for the realization of smart sensoristic devices due to the possibility to detect the target analyte via a change in colour or emission. Recently (since 2006), carbon nanoparticles, which are a "new class" of nanostructures based on carbon atoms, have been widely used in sensing applications due to their intriguing optical properties. The scientific literature on this topic started from 2006 and a progressive increase in the corresponding number of publications has been observed. This review summarises the application of carbon nanoparticles in the sensing field, focusing on chemical and ion sensing.

Synthesis of green fluorescent carbon quantum dots from the latex of Ficus benghalensis for the detection of tyrosine and fabrication of Schottky barrier diode

Green fluorescent CQDs have been synthesized from the latex of ficus benghalensis and polyethyleneimine and utilized for the detection of tyrosine. Further, fabricated a Schottky barrier diode.

Interpol review of detection and characterization of explosives and explosives residues 2016-2019

This review paper covers the forensic-relevant literature for the analysis and detection of explosives and explosives residues from 2016-2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/Resources/Documents#Publications.

Carbon Dots: Zero-Dimensional Carbon Allotrope with Unique Photoinduced Redox Characteristics

Carbon dots (CDots) exploit and enhance the intrinsic properties of small carbon nanoparticles. Their optical absorptions and photoinduced redox characteristics are competitive with those of conventional semiconductor quantum dots at one end and fullerenes and other carbon nanomaterials at the other. Highlighted in this mini review are the effective photon harvesting over a broad spectral range by CDots and their subsequent excited-state charge transfer processes and interactions, which have enabled their use as sensors, for photodynamic effects, and in various energy conversion technologies.

Zero-Dimensional Carbon Allotropes-Carbon Nanoparticles Versus Fullerenes in Functionalization by Electronic Polymers for Different Optical and Redox Properties

Fullerene cages are known as being able to participate in radical initiated copolymerization reactions with vinyl monomers for polymer-functionalized fullerenes. In this work, poly(N-vinylcarbazole) (PVK) was selected as a representative of electronic polymers in the functionalization of fullerene C₆₀ by the same copolymerization reaction to yield the PVK-C₆₀. Similarly found was that small carbon nanoparticles could also participate in the same copolymerization reaction for the nanoparticles to be surface-functionalized and -passivated by the attached PVK polymers, which are structurally adhering to the general definition on carbon dots (CDots), thus PVK-CDots. In the comparison between PVK-CDots and PVK-C₆₀, the former was found to be more absorptive and therefore more effective in photon harvesting across the visible spectral region and also brightly fluorescent, orders of magnitude more so than the latter. Similar to the PVK-C₆₀ and C₆₀ cages in general, the PVK-CDots exhibited significant photoinduced electron accepting characteristics and, at the same time, also extraordinary electron donating abilities that are not available to fullerenes. Because fullerene-based composites with electronic polymers including PVK have found significant applications in optoelectronic devices and systems, the prospect of CDots represented by the PVK-CDots for similar purposes is discussed.

Carbon–TiO2 hybrid dots in different configurations – optical properties, redox characteristics, and mechanistic implications

Carbon–TiO₂ hybrid dots in different structural configurations were found to exhibit very different optical properties and photoinduced redox characteristics.