Fluorescent Carbon Nanoparticles: Synthesis, Characterization, and Bioimaging Application

Ray, Sekhar C.; Saha, Arindam; Jana, Nikhil R.; Sarkar, Rupa

doi:10.1021/jp905912n

Cited by 1,094 publications

(840 citation statements)

References 44 publications

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“…42 These NPs offer much promise in view of their chemical inertness, high surface area, and good surface grafting capacity. 43 Preliminary data indicate that both C-dots 44 and GQDs 45 exhibit minimal cytotoxicity to exposed cells. Silicon QDs as well offer a promising alternative to semiconductor QDs, although their photoluminescence quantum yields (5À10%) are lower than those of CdSe QDs.…”

Section: Discussionmentioning

confidence: 99%

Quantum Dot Cytotoxicity and Ways To Reduce It

2012

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T he dramatic increase in the use of nanoparticles (NP) in industry and research has raised questions about the potential toxicity of such materials. Unfortunately, not enough is known about how the novel, technologically-attractive properties of NPs correlate with the interactions that may take place at the nano/bio interface. The academic, industrial, and regulatory communities are actively seeking answers to the growing concerns on the impact of nanotechnology on humans. In this Account we adopt quantum dots (QDs) as an illustrative example of the difficulties associated with the development of a rational sciencebased approach to nanotoxicology.The optical properties of QDs are far superior to those of organic dyes in terms of emission and absorption bandwidths, quantum yield, and resistance to photobleaching. Moreover, QDs may be decorated with targeting moieties or drugs and, therefore, are candidates for site-specific medical imaging and for drug delivery, for example in cancer treatment. Earlier this year researchers demonstrated that QD-based imaging using monkeys caused no adverse effects although QDs accumulated in lymph nodes, bone marrow, liver, and spleen for up to 3 months after injection. Such persistence of QDs in live animals does, however, raise concerns about the safety of using QDs both in the laboratory and in the clinic.Researchers anticipate that QDs will be increasingly used not only in clinical applications but also in various manufactured products. For example, QD-solar cells have emerged as viable contenders to complement or replace dye-sensitized solar cells; CdTe/CdS thin film cells have already captured approximately 10 percent of the global market, and in addition, QDs can serve as components of sensors and as emitting materials in LEDs. Given the clear indications that QDs will inevitably become components of a wide range of manufactured and consumer products, researchers and policy makers need to understand the possible health risks associated with exposure to QDs.In this Account, we initially review the known mechanisms by which QDs can damage cells, including oxidative stress elicited by reactive oxygen species (ROS). We discuss lesser-known impairments induced in cells by nanomolar to picomolar concentrations of QDs, which imply that cadmium-containing QDs can exert genotoxic, epigenetic, and metalloestrogenic effects. These observations strongly suggest that minute concentrations of QDs could be sufficient to cause long lasting, even transgenerational, effects. We also consider various modes by which humans could be exposed to QDs in their work or through the environment. Although considerable advances have been made in enhancing the stability and overall quality of QDs, over time they can partially degrade in the environment or in biological systems, and eventually cause small, but cumulative undesirable effects.A combination of toxicological, genetic, epigenetic and imaging approaches is required to create comprehensive guidelines for evaluating the nanotoxicity of nanomate...

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Section: Discussionmentioning

confidence: 99%

Quantum Dot Cytotoxicity and Ways To Reduce It

2012

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“…Because of these features, various methods for fluorescent CNP synthesis have been reported by using carbon-based materials as carbon resources. [14,19,20] For example, top-down methods include laser ablation of carbon powder [14], electrochemical oxidation [21] and arc discharge [22]; bottom-up methods consist of microwave synthesis, [23,24] combustion soots of candles, [25,26] thermal oxidation of carbon precursor by employing silica or zeolites as carriers [27,28] commercial activated carbon [29], lampblack [30] and watermelon peel as carbon resources [31]. All these methods suffer to some degree from drawbacks like tedious processes, harsh synthetic conditions or expensive starting materials.…”

Section: Introductionmentioning

confidence: 99%