Synthesis, functionalization and bioimaging applications of highly fluorescent carbon nanoparticles

Abstract

Highly fluorescent crystalline carbon nanoparticles (CNPs) have been synthesized by one step microwave irradiation of sucrose with phosphoric acid at 100 W for 3 min 40 s. This method is very simple, rapid and economical and hence can be used for large scale applications. The average particle sizes are 3 to 10 nm and they emit bright green fluorescence under the irradiation of UV-light. Therefore, the particles can be used as a unique material for bioimaging as well as drug delivery. To further increase the fluorescence property of the synthetic carbon nanoparticles we simply functionalized them by using different organic dyes, such as fluorescein, rhodamine B and α-naphthylamine; the maximum fluorescence intensity was observed for the particles functionalized with fluorescein. It is very interesting to note that all of those compounds show maximum fluorescence intensity at 225 nm excitation wavelength and for any excitation wavelength the peak positions are exactly same the position as that of CNPs itself, which is completely different from the individual precursors (dyes). All of the above compounds, including CNPs, have also been successfully introduced into the erythrocyte enriched fraction of healthy human blood cells with minimum cytotoxicity.

Enhanced photoluminescence and characterization of multicolor carbon dots using plant soot as a carbon source

“…Carbon nanomaterials including carbon nanotubes, nanoparticles, nanofibers, graphene oxide and carbon dots (C-dots), have attracted great attention due to their wide applications in solar cells [1], bioimaging [2], photocatalysts [3], nanoelectronic devices [4], photodynamic therapy [5] and gene delivery [6]. Among them, carbon dots are a new class of functional nanomaterials exhibiting their inherently unique photoluminescent properties, such as wavelengthtuneable emission, excellent solubility, good biocompatibility and chemical inertion [7][8][9][10].…”

“…However, all these above-mentioned methods suffer from more or less drawbacks such as complex and time-consuming processes, severe synthetic conditions, and high cost, which limit their wide applications [25]. Thus, a low-cost and facile synthesis of C-dots from an economical carbon source is highly desired [2,9].…”

Synthesis of biocompatible multicolor luminescent carbon dots for bioimaging applications

“…Zhu et al [4] produced C-dots by a microwave method, which showed bright luminescence when their surfaces were passivated with diamine-terminated oligomeric poly(ethylene glycol) (PEG 200). Chandra et al [5] prepared C-dots by a similar method, but their luminescence intensity was too weak for biological applications. They were able to enhance the luminescence intensity of the C-dots by conjugating their surfaces with fluorescent probes.…”

Development of multicolor carbon nanoparticles for cell imaging

“…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.…”