High throughput electron transfer from carbon dots to chloroplast: a rationale of enhanced photosynthesis (original) (raw)

Photoinduced Electron Transfer in Carbon Dots with Long Wavelength Photoluminescence

The Journal of Physical Chemistry C, 2018

Carbon dots have often been studied to investigate their unique optical properties such as excitation wavelength-independence emission. Carbon dots have also been shown to undergo electron transfer in different situations. This study endeavors to investigate the properties of carbon dots photoluminescence and electron transfer. Herein, the preparation and characterization of carbon dots which exhibit long wavelength photoluminescence has been reported. These carbon dots exhibit quenching when exposed to metal ions in proportion to the reduction potential of the metal, which experimental evidence has shown for the first time. This property of metal ion reduction potential-dependent quenching has been studied to show the collisional electron transfer from amine groups in carbon dots to the metal ions. Therefore, the photoluminescence in these carbon dots are directly related to organic functional groups on the surface of the carbon dots.

Photosynthesis and crop productivity is enhanced by glucose-functionalized fluorescent carbon dots

2019

From global food security to textile production and biofuels, the demands currently made on plant photosynthetic productivity will continue to increase. Enhancing photosynthesis using designer, green and sustainable materials offers an attractive alternative to current genetic-based strategies and promising work with nanomaterials has recently started to emerge. Here we describe in planta use of carbon-based nanoparticles produced by low-cost renewable routes that are bioavailable to mature plants. Uptake of these functionalised nanoparticles from the soil improves photosynthesis and also increases crop production. We show for the first time that glucose-functionalization enhances nanoparticle uptake, photoprotection and pigment production, unlocking enhanced yields. This is demonstrated in Triticum aestivum Apogee (dwarf bread wheat) and results in an 18% increase in grain yield. This establishes the viability of a functional nanomaterial to augment photosynthesis as a route to inc...

Self-illumination of Carbon Dots by Bioluminescence Resonance Energy Transfer

Scientific Reports

Carbon-dots (CDs), the emerging fluorescent nanoparticles, show special multicolor properties, chemical stability, and biocompatibility, and are considered as the new and advanced imaging probe in replacement of molecular fluorophores and semiconductor quantum dots. However, the requirement of external high power light source limits the application of fluorescent nanomaterials in bio-imaging. The present study aims to take advantage of bioluminescence resonance energy transfer mechanism (BRET) in creating self-illuminating C-dots. Renilla luciferase (Rluc) is chosen as the BRET donor molecule. Conjugation of Renilla luciferase and C-dots is necessary to keep their distance close for energy transfer. The optimal condition for achieving BRET is investigated by studying the effects of different factors on the performance of BRET, including the type of conjugation, concentration of carbon dots, and conjugation time. The linear relationship of BRET efficiency as a function of the amount ...

Bio-Derived Fluorescent Carbon Dots: Synthesis, Properties and Applications

Molecules

The transformation of biowaste into products with added value offers a lucrative role in nation-building. The current work describes the synthesis of highly water-soluble, luminous carbon quantum dots (CQDs) in the size range of 5–10 nm from discarded rice straw. The small spherical CQDs that were formed had outstanding optical and luminescent qualities as well as good photostabilities. By performing quantitative multi-assay tests that included antioxidant activities, in vitro stability and colloidal assay investigations as a function of different CQD concentrations, the biocompatibility of CQDs was evaluated. To clearly visualize the type of surface defects and emissive states in produced CQDs, excitation-dependent fluorescence emission experiments have also been carried out. The “waste-to-wealth” strategy that has been devised is a successful step toward the quick and accurate detection of Cu2+ ion in aqueous conditions. The fluorescence-quenching behavior has specified the concen...

Multifaceted applications of green carbon dots synthesized from renewable sources

Advances in Colloid and Interface Science, 2019

Fluorescent carbon dots (CDs) are an emerging class of nanomaterials in the carbon family. There are various inexpensive and renewable resources that can be used to synthesize green CDs, which have received immense attention from researchers because of their improved aqueous solubility, high biocompatibility, and eco-friendly nature compared with chemically derived CDs. Additional surface passivation is not required, as heteroatoms are present on the surface of green CDs in the form of amine, hydroxyl, carboxyl, or thiol functional groups, which can improve their physicochemical properties, quantum yield, and the probability of visible light absorption. Green CDs have potential applications in the fields of bioimaging, drug/gene delivery systems, catalysis, and sensing. Since their discovery, there have been several review articles that describe the synthesis of green CDs and some of their applications. However, there are no review articles describing the synthesis and complete applications of green CDs. Here, we provide detailed information regarding their synthesis and applications based on the available literature. In addition, we discuss some of the less explored applications of green CDs and the challenges that remain to be overcome.

Enhancement of Photosynthetic Productivity by Quantum Dots Application

Nonmagnetic and Magnetic Quantum Dots, 2018

The challenge of climate change promotes use of carbon neutral fuels. Biofuels are made via ixing carbon dioxide via photosynthesis which is ineicient. Light trapping pigments use restricted light wavelengths. A study using the microalga Botryococcus braunii (which produces bio-oil), the bacterium Rhodobacter sphaeroides (which produces hydrogen), and the cyanobacterium Arthrospira platensis (for bulk biomass) showed that photosynthetic productivity was increased by up to 2.5-fold by upconverting unused wavelengths of sunlight via using quantum dots. For large scale commercial energy processes, a 100fold cost reduction was calculated as the break-even point for adoption of classical QD technology into large scale photobioreactors (PBRs). As a potential alternative, zinc sulide nanoparticles (NPs) were made using waste H 2 S derived from another process that precipitates metals from mine wastewaters. Biogenic ZnS NPs behaved identically to ZnS quantum dots with absorbance and emission maxima of 290 nm (UVB, which is mostly absorbed by the atmosphere) and 410 nm, respectively; the optimal wavelength for chlorophyll a is 430 nm. By using a low concentration of citrate (10 mM) during ZnS synthesis, the excitation wavelength was redshifted to 315 nm (into the UVA, 85% of which reaches the earth's surface) with an emission peak of 425 nm, i.e., appropriate for photosynthesis. The potential for use in large scale photobioreactors is discussed in the light of current PBR designs, with respect to the need for durable UV-transmiting materials in appropriate QD delivery systems.

Amino Functionalization of Carbon Dots Leads to Red Emission Enhancement

The Journal of Physical Chemistry Letters, 2019

The availability of carbon dots (CDots) with bright red photoluminescence (PL) would significantly broaden the range of their biological and optoelectronic applications. We present a theoretical model that predicts that amino functionalization of CDots not only shifts their PL to longer wavelengths but also preserves large oscillator strengths of the fundamental radiative transitions of CDots. The model considers the optical response of amino-functionalized CDots determined by molecule-like subunits of polycyclic aromatic hydrocarbons with one, two, or three −NH 2 groups at the CDots' surface; the excited state of those subunits is characterized by strong charge separation between the amino groups and CDots' carbon core. Such a separation determines the Stokes shift of the CDots' emission, which increases with the growing amount of the amino functional groups at the CDot surface. Our model explains the experimentally observed dependence of the PL spectra of CDots on the excitation wavelength, the phenomenon well documented in the literature for nitrogencontaining CDots.

Synthesis of ecofriendly fluorescent carbon dots and their biomedical and environmental applications

Materials Technology, 2018

Green Synthesis of nanoparticles is an emerging field with enormous advantages over conventional synthesis methods. Herein we have reported a green method for the preparation of water soluble polydisperse carbon dots (c-dots) from Cocos nucifera frond pinnae by a modified version of the 'single step hydrothermal carbonization'. C-dots having blue emission were obtained with this method and we further evaluated the effect of metal ions interactions on c-dots, as a sharp decrease in photoluminescence was observed. The synthesized c-dots were found bioactive against B.subtilis, M. smegmatis and S. aureus as determined by the well diffusion assay. We also explored nanotheranostic applications of c-dots as biosensor matrix in DNA hybridization sensor for pancreatic cancer and in bioimaging of cancer cells. This study demonstrated that c-dots can be explored for numerous biomedical and environmental applications in a variety of fields owing to the cost effective synthesis, biocompatibility and excellent physico-chemical properties.