Highly Biocompatible, Fluorescence, and Zwitterionic Carbon Dots as a Novel Approach for Bioimaging Applications in Cancerous Cells

Abstract

Highly biocompatible, excellently photostable, nitrogen- and sulfur-containing novel zwitterionic carbon dots (CDs) were synthesized by microwave-assisted pyrolysis. The size of CDs were 2–5 nm, with an average size of 2.61 ± 0.7 nm. CDs were characterized by UV/vis spectroscopy, fluorescence spectroscopy, zeta potential, Fourier-transform infrared spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy. CDs were known to emit blue fluorescence when excited at 360 nm, that is, UV region, and emit in the blue region of visible spectrum, that is, at 443 nm. CDs showed excitation-independent photoluminescence behavior and were highly fluorescent even at lower concentration under UV light. These CDs were highly fluorescent in nature, with the quantum yield being as high as 80%, which is comparable to that of organic dyes. The CDs were further used to image two different oral cancer cell lines, namely, FaDu (human pharyngeal carcinoma) and Cal-27 (human tongue carcinoma). The cell viability assay demonstarted that CDs were highly biocompatible, which was further confirmed by the side scattering studies as no change in the granularity was observed even at the highest concentration of 1600 μg/mL. The generation of reactive oxygen species (ROS) was also investigated and negligible generaton of ROS was detected. In addition to that, the uptake phenomenon, cell cycle analysis, exocytosis, and cellular uptake at 4 °C and in the presence of ATP inhibitor were studied. It was found that CDs easily cross the plasma membrane without hampering the cellular integrity.

Evaluation of the Environmental Impact and Efficiency of N-Doping Strategies in the Synthesis of Carbon Dots

“…The first approach is based on the breakdown of large graphite materials in smaller carbon-based materials [16]. However, bottom-up methods, such as microwave-assisted processes [17][18][19][20], appear to be the most widely used for the preparation of CDs, which consist of the synthesis of CDs from smaller carbon precursors (small organic molecules) [21,22]. Among these, citric acid (CA) is one of the most used [17,[23][24][25][26].…”

Multifunctional Nanohybrid of Palladium Nanoparticles Encapsulated by Carbon‐Dots for Exploiting Synergetic Applications

“…Compared to other fluorescent nanomaterials, the C‐dots can be easily synthesized from different kind of sources including organic molecules, biowastes, proteins, amino acids, and so on . Moreover, the surface of C‐dots can be modified with several capping agents to improve their fluorescence properties according to the applications . That's why the C‐dots have been extensively utilized in the fields of chemo‐ and biosensors, and optoelectronic applications.…”

Dual Role of Lanthanum Oxide Nanoparticles Functionalized Co‐Polymeric Micelle for Extended Anti‐Cancer Drug Delivery

“…Therefore, Ln 3+ are considered as promising luminescent supporters for applications including bioimaging, sensing, therapy, lighting and displays, as well as inphotovoltaic devices . Lanthanide‐doped nano crystals have attracted wide attention due to their broad application range including carbon quantum dots (CDs) . Xu et al., proposed lanthanum oxide as good MRI agents for bio‐imaging and their fluorescent properties are similar to quantum dots (QDs) except for their weaker fluorescent intensities…”

“…[21] Lanthanide-doped nano crystals have attracted wide attention due to their broad application range including carbon quantum dots (CDs). [22] Xu et al, proposed lanthanum oxide as good MRI agents for bio-imaging and their fluorescent properties are similar to quantum dots (QDs) except for their weaker fluorescent intensities. [23] In the present work, we propose the development of a new polymeric micelle-based drug delivery system to improve the utilization rate of Paclitaxel (PTX) for cancer therapy.…”