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Phototherapy Using Nanomaterials
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
A. N. Resmi, V. Nair Resmi, C. R. Rekha, V. Nair Lakshmi, Shaiju S. Nazeer, Ramapurath S. Jayasree
Gold is one of the unique noble metals, which has been known for its resistance against corrosion and oxidation. Gold nanomaterials have attracted considerable attention due to their interesting optical and physical properties, which are different from their bulk state. These properties have been known for centuries for use in medicinal applications [16]. Bulk gold is yellow in color due to the reduction in reflectivity for light toward the end of the electromagnetic spectrum [17]. When the size of gold is reduced to nanoparticle dimension, the ratio of radius of the particle and wavelength of light becomes important. Metallic nanoparticles exhibit attractive colors, due to the collective oscillation of the electrons in the conduction band, known as the surface plasmon oscillation. The oscillation frequency of these materials falls in the visible region, which results in strong SPR absorption. Free electrons in metals known as plasmons, move freely and can be easily excited by an electromagnetic wave. This collective oscillation of conduction electrons in metal is referred as SPR [6]. In other words, when the wavelength of electromagnetic radiation is much larger than the nanoparticle size, it can set up standing resonance conditions, which lead to the localized surface plasmon resonance (LSPR) in metal nanoparticles [7].
Understanding the Role of Existing Technology in the Fight Against COVID-19
Published in Ram Shringar Raw, Vishal Jain, Sanjoy Das, Meenakshi Sharma, Pandemic Detection and Analysis Through Smart Computing Technologies, 2022
Plasmonic biosensors may offer reliable detection of COVID-19 virus as well. The localized surface plasmon resonance (LSPR)-based sensors have been used to detect clinical analytes [32]. The LSPR refers to the coherent oscillations induced by the photons in the conducting surface electrons. This localized plasmonic resonance can be modulated as a result of change in certain properties such as refractive index and molecular binding. A dual functional plasmonic biosensor was tested by Qiu et al. [33]. The device was capable of inducing plasmonic photothermal (PPT) effect by using gold nanoparticle islands. The nanoparticles strongly absorb the photons and cause localized heating due to non-radiative emission. This phenomenon is used for the hybridization of the nucleic acid strands. The LSPR is then used for the detection of the COVID-19 virus.
Targeted Therapy for Cancer Stem Cells
Published in Surinder K. Batra, Moorthy P. Ponnusamy, Gene Regulation and Therapeutics for Cancer, 2021
Rama Krishna Nimmakayala, Saswati Karmakar, Garima Kaushik, Sanchita Rauth, Srikanth Barkeer, Saravanakumar Marimuthu, Moorthy P. Ponnusamy
Nanoparticles can also be formulated with gold due to its properties of localized surface plasmon resonance, facile synthesis and functionalization, and excellent biocompatibility [105]. It has been well established that AuNPs are non-toxic and non-immunogenic [106]. These days, AuNPs can be easily synthesized in high yields like nano-spheres, nano-rods, and nano-cages. Gold has radiative properties like absorption, scattering and localized surface plasmon resonance making it very suitable for photothermal therapy and easy surface modifications make them attractive options for drug delivery and cancer therapies [105]. People have successfully coated and loaded these particles with drugs like capecitabine, doxorubicin, and cisplatin [107, 108]. AuNPs coated with thio-polyethylene glycol, and thio-glucose have been used to target CSCs specifically due to their high glucose uptake. AuNPs can also be modified with microRNA duplexes specific for CSCs to allow precise target delivery [109].
Magnetoliposomes: recent advances in the field of controlled drug delivery
Published in Expert Opinion on Drug Delivery, 2021
Sérgio R. S. Veloso, Raquel G. D. Andrade, Elisabete M. S. Castanheira
A strategy that has been recently explored consists of the photothermal effect upon laser irradiation of the nanoparticles with near-infrared (NIR, 700–1000 nm) light [8,50]. Photothermia explores the phenomenon of localized surface plasmon resonance and the most commonly used material is gold nanoparticles [51,52]. The photothermia phenomenon consists in the enhancement of the local electromagnetic field upon application of an external oscillating electric field, from which the heating effect is associated with the fast phase loss of the coherently excited electrons via electron-electron collisions. Interestingly, besides the commonly used plasmonic gold nanoparticles, magnetite nanoparticles have also displayed good photothermal conversion efficiency [53,54], which can be used as an alternative or in combination with an AMF. In ferrites, the photothermal effect has been associated with the photoexcited electrons temporarily transit from the valence band to the conduction band, followed by electron-hole recombination (bridged by intrinsic mid-band gap states or trap-gaps due to internal defects) that can occur through non-radiative relaxation [55]. Hereby, photothermia can be used as an alternative or in combination with an AMF. For example, Shen et al. [8] developed magnetic liposomes (DPPC:cholesterol 4:1) loaded with iron oxide nanoparticles and doxorubicin, which after intravenous injection in mice, were slowly enriched in the tumor and allowed both the photothermal effects through irradiation with a continuous 808 nm laser light (2 W.cm−2) and contrast in magnetic resonance imaging (MRI).
Aptamer-based sensing of breast cancer biomarkers: a comprehensive review of analytical figures of merit
Published in Expert Review of Molecular Diagnostics, 2021
Rajesh Ahirwar, Nabab Khan, Saroj Kumar
Colorimetric methods that allow biomarker detection based on color changes visible to naked eyes or can be quantitatively measured by simple portable optical detectors are another group of optical methods. One of the common colorimetric methods based on gold nanoparticles is the localized surface plasmon resonance (LSPR). The LSPR-based aptasensors utilize the inter-particle distance-dependent color transition property of AuNPs. The AuNPs at nanomolar concentrations exhibits vibrant colors in the visible region due to very high molar extinction coefficient. For example, monodispersed AuNPs (size 10–50 nm) appear bright ruby red (absorption maxima at 520 nm), but changes to pale blue or purple upon aggregation (absorption maxima above 700 nm). This property of AuNPs has been widely harnessed; capping the AuNPs with aptamers allow them to remain mono-dispersed in high salt solution (aptamer prevent AuNP aggregation via electrostatic repulsion), but the presence of the target marker detaches aptamer from nanoparticles, allowing them to aggregate by the salt solution (Figure 3) [69,70].
Increasing the efficiency of the retinoblastoma brachytherapy protocol with ultrasonic hyperthermia and gold nanoparticles: a rabbit model
Published in International Journal of Radiation Biology, 2020
Somayeh Moradi, Manijhe Mokhtari-Dizaji, Fariba Ghassemi, Shahab Sheibani, Fahimeh Asadi Amoli
The metal nanoparticles absorb energy from external sources such as laser, ultrasonic waves, and electromagnetic radiation so localized surface plasmon resonance (LSPR) occurs. A wave of plasmonic intensification occurs at the junction of the metal and the dielectric medium, which is caused by the very disordered and irregular state of the electron. As a result of resonance, nanoparticles convert energy from external sources into heat, causing hyperthermia damage to cancer cells (Chen et al. 2016). In this study, in the case of the gold nanoparticle injection group (GNP), only retinoblastoma cells inside the vitreous were necrotic and destroyed, while the tumor mass contained many viable cells. However, the size of the tumor after about 3 weeks was ∼0.7 times the initial size. Also, in the groups of brachytherapy, hyperthermia, and hyperthermia in the presence of gold nanoparticles (hyperthermia (GNP)), in addition to the necrosis of some viable cells in the vitreous, a number of retinoblastoma mass cells were also necrotic. The tumor size after 3 weeks was ∼0.49, 0.45, and 0.43 times its initial size, respectively. The results of the evaluation of pathologic and ultrasound images in the follow-up of in vivo experiments concluded that both hyperthermia and brachytherapy treatments had hemorrhage, inflammation, and scarring in the retina, and if both methods were used, these complications would be increased. However, more retinoblastoma cells were necrotic, and if GNPs were injected, even necrotic retinoblastoma cells in the vitreous would disappear.