Effects of Nanocrystal Morphologies on Cytotoxicity
Suresh C. Pillai, Yvonne Lang in Toxicity of Nanomaterials, 2019
Particle geometry also has implications for the properties of semiconductor NPs (quantum dots). A study of the optical properties of spherical and elongated nanocrystals showed that the nanorods had enhanced absorption cross sections relative to the spheres and, therefore, improved photostability (Htoon et al. 2003). Particle shape was also found to affect the bleach recovery rates of CdSe nanospheres vs nanorods, due to the larger number of excitation states in the rods (Mohamed et al. 2001). Furthermore, while spherical quantum dots exhibit plane polarized emission, nanorods have polarized emission along the particle long axis (Hu et al. 2001). Finally, it has been shown that the emission of CdSe nanorods can be switched on and off via application of an external electric field (Rothenberg et al. 2005).
A Pilot Study in Non-Human Primates Shows No Adverse Response to Intravenous Injection of Quantum Dots
Lajos P. Balogh in Nano-Enabled Medical Applications, 2020
Quantum dots have been used in biomedical research for imaging [1, 2], diagnostics [3, 4] and sensing purposes [5, 6]. However, concerns over the cytotoxicity of their heavy metal constituents [7, 8] and conflicting results from in vitro [7, 9] and small animal [10–14] toxicity studies have limited their translation towards clinical applications. Here, we show in a pilot study that rhesus macaques injected with phospholipid micelle-encapsulated CdSe/CdS/ZnS quantum dots do not exhibit evidence of toxicity. Blood and biochemical markers remained within normal ranges following treatment, and histology of major organs after 90 days showed no abnormalities. Our results show that acute toxicity of these quantum dots in vivo can be minimal. However, chemical analysis revealed that most of the initial dose of cadmium remained in the liver, spleen and kidneys after 90 days. This means that the breakdown and clearance of quantum dots is quite slow, suggesting that longer-term studies will be required to determine the ultimate fate of these heavy metals and the impact of their persistence in primates.
Medication: Nanoparticles for Imaging and Drug Delivery
Harry F. Tibbals in Medical Nanotechnology and Nanomedicine, 2017
In the earlier sections, we discussed the use of nanoparticles such as quantum dots for enhancement of conventional diagnostic images to show anatomical features and identify tumor cells [31-45,410]. Fluorescent quantum dot bioconjugates are useful not only for diagnostic imaging and photothermal therapy, but also for sensing and probing cellular processes. All of the advantages of nanodots for conventional radiology image enhancement are equally applicable for molecular scale sensing: signal strength, absence of photobleach-ing, stability under in vivo conditions, emission wavelength tunable with small variations in particle size, and simultaneous excitation of multiple wavelengths [40,61,442,443]. Although larger than fluorescent molecules, quantum dots are useful because they are still small enough to enter cells with minimal disruption, and can be attached to target proteins and structures with minimal alteration of the target’s movement and less impact on its chemical properties.
Preparation of liposomal doxorubicin-graphene nanosheet and evaluation of its in vitro anti-cancer effects
Published in Journal of Liposome Research, 2019
Samira Tajvar, Soheila Mohammadi, Alireza Askari, Sajjad Janfaza, Maryam Nikkhah, Elnaz Tamjid, Saman Hosseinkhani
The tracking of anti-cancer agents, upon their administration, can play an important role to formulate effective anti-cancer therapeutics. Quantum dots have various applications in biological research such as labeling, particle tracking, multi-coloured and multi-modal imaging especially in tumours and drug delivery (Zhu et al. 2013, Samadikhah et al. 2016). The main disadvantage of colloidal semiconductor quantum dots is their inherent toxicity (Shen et al. 2012). Graphene quantum dots (GQDs), a new generation of quantum dots, are little pieces of graphene sheets that demonstrate very low toxicity and are soluble in various solvents. Considering their special characteristics, such as light absorption and photoluminescence, GQDs have the potential to be used in bioimaging, tracking, photodynamic and photothermal therapy (Singh et al. 2011, Shen et al. 2012, Li et al. 2013, 2016, Yang et al. 2013, Bacon et al. 2014). Dong et al. treated human breast cancer MCF-7 cells with green emitting GQDs and indicated that GQDs were able to label the cell membrane, the cytoplasm, and the nucleus simultaneously. Gao et al. reported a GO-based fluorescent magnetic hybrid for delivery of Dox into hepatocellular carcinoma cell line. They used GO for in vitro imaging and showed high cellular uptake of the hybrid system (Gao et al. 2013). Xu et al. have been summarized several researches on imaging by GQDs (Xu et al. 2013).
An overview on the current status of cancer nanomedicines
Published in Current Medical Research and Opinion, 2018
Nasimudeen R. Jabir, Khalid Anwar, Chelapram K. Firoz, Mohammad Oves, Mohammad Amjad Kamal, Shams Tabrez
Nano-devices include nano-machines, nano-fiber sensors, and other nano-scale micro-fabrication based entities9. Till now, gold nano-shells10, iron oxide nano-crystals11 and quantum dot12 based nanomedicines are developed for the diagnosis and treatment of cancer. Gold nano-shells (10–300 nm in diameter) consist of a dielectric core (e.g. silica) surrounded by a thin gold shell. On the other hand, an iron oxide nano-crystal (5–100 nm in diameter) is used as a contradictory agent in magnetic resonance imaging and has super-paramagnetic properties. They have the potential to accurately diagnose arthritis, atherosclerosis and cancer13,14. By using this diagnostic approach, a doctor could outline the situation of lymph nodes in patients with breast, lung, endometrial and prostate cancer. Quantum dots (composed of an inorganic elemental core) are a novel type of semiconductor surrounded by a metal shell. Heavy metals such as cadmium are present in the quantum dots, therefore the possible toxicity associated with these metals should be considered before their application15.
Role of CdSe quantum dots in the structure and antibacterial activity of chitosan/poly ɛ-caprolactone thin films
Published in Egyptian Journal of Basic and Applied Sciences, 2018
M.S. Meikhail, A.M. Abdelghany, W.M. Awad
Quantum dots (QDs) are spherical nano-sized crystals that may be formed of almost all semiconducting metals including CdSe, CdS, CdTe, PbS and ZnS while, alloys or any other metals may be used [16,17] . Cadmium selenide (CdSe) may be considered as an archetypal quantum dot with size range from 2 to 10 nm in diameter (10–50 atoms). Many types of quantum dot will emit light of specific frequencies if electricity or light is applied to them. These frequencies can be precisely tuned by changing the dot's size, [18,19] , giving rise to many applications. QDs were introduced to biological cell as alternative fluorescent probes in recent years. It uses in biological imaging, bio-sensing and intracellular detection and targeting, solar cells, quantum computing, transistors, LEDs and diode lasers [20]. Density function theory (DFT) is computational quantum mechanical method utilized as a part of physical science, material science to research the electronic structure (the ground state) of numerous body system, specifically particles, and atoms. It is a standout amongst the most well-known and effective quantum mechanical ways to deal with matter.
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