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Toxicity and Cellular Uptake of Gold Nanoparticles: What We Have Learned So Far *
Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Alaaldin M. Alkilany, Catherine J. Murphy
The excited electrons in the conduction band lose their energy in form of heat to the surrounding media; the heat generation is the basis of the photothermal therapy (Jain et al. 2008). In these experiments, gold nanoparticles are designed to absorb light in the water window of 800–1200 nm by virtue of their shape. Illumination at their absorbance maximum increases the temperature of the solution—some reports state >30°C (Hirsch et al. 2003). This temperature rise is enough to kill nearby cells (e.g., cancer cells or pathogenic bacteria) (Hirsch et al. 2003; Dickerson et al. 2008; Jain et al. 2008; Norman et al. 2008; von Maltzahn et al. 2009). The optical properties of gold nanoparticles and their corresponding applications are summarized in Fig. 11.2.
Medication: Nanoparticles for Imaging and Drug Delivery
Published in Harry F. Tibbals, Medical Nanotechnology and Nanomedicine, 2017
Nanoshells and similar quantum resonance nanoparticles can destroy attached cells by absorbing heat on irradiation with infrared light at a frequency that is not absorbed by tissue. The plasmon resonance absorption heats the particles and destroys any cells selectively bound to the nanoshell particle. The nanoshells typically consist of a dielectric core and a gold shell, whose core-shell ratio determines their optically resonant frequency. Thus the nanoparticles can be fabricated with specific absorption characteristics, depending on composition, size, and shell thickness. Nanoparticles with intense absorption, light scattering, and emission properties in the “water window” of the NIR (800-1300 nm) are optimally suited for bioimaging and biosensing applications [55,56].
Carbon quantum dots: recent progresses on synthesis, surface modification and applications
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Masoud Farshbaf, Soodabeh Davaran, Fariborz Rahimi, Nasim Annabi, Roya Salehi, Abolfazl Akbarzadeh
Li et al. reported that the source of the PL of prepared CQDs was due to carboxylate groups created at the surface of particle [45]. They claimed that some oxygen-containing radicals at the surface of the preliminary carbon precursors, produced by laser irradiation, would be the source of the PL. As they suggested, two factors were leading to tunable performance. The first factor was controlling the size of obtained particles similar to what was detected in semiconductor nanocrystals and the second was the diverse oxygen-containing groups. It turned out that, CQDs prepared by electrochemical oxidation technique employing MWCNTs exhibited blue PL and λex-dependent emission whose PL does not need passivation step [26]. Li et al. produced CQDs from glucose as carbon precursor employing ultrasonic treatment technique [11]. Obtained CQDs showed N-IR emission after excitation by N-IR light which is very valuable for bioapplications due to the transparency of body tissues in this band known as “water window” (Figure 13). The fabrication technique and the involved surface chemistry are the most significant factors that determine the QY of CQDs [7]. CQDs prepared by laser ablation with size of 5 nm had QY about 4–10% relying on the efficiency of the reaction on surface passivation and the excitation wavelength [63]. QY of 7 nm CQDs prepared by thermal decomposition methods was only 3% [12].