China
Africa
Explore chapters and articles related to this topic
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].
Green Metal-Based Nanoparticles Synthesized Using Medicinal Plants and Plant Phytochemicals against Multidrug-Resistant Staphylococcus aureus
Published in Richard L. K. Glover, Daniel Nyanganyura, Rofhiwa Bridget Mulaudzi, Maluta Steven Mufamadi, Green Synthesis in Nanomedicine and Human Health, 2021
Abeer Ahmed Qaed Ahmed, Lin Xiao, Tracey Jill Morton McKay, Guang Yang
The synthesis of noble metal (gold, silver, palladium and platinum) NPs and inorganic oxides (such as titanium and zinc oxide) NPs have attracted great attention in the field of therapeutics, disease treatments, disease diagnosis, biosensors, cancer detection, cancer treatment, drug delivery, cosmetics, antimicrobial agents, antifungal agents, medical devices and medical instruments (Singh et al., 2016; Salouti and Derakhshan 2019; Karthik et al. 2020). In addition to the gold and silver NPs reviewed in this chapter, copper, zinc oxide, iron, titanium dioxide, nickel oxide, and lead have also been used (Table 10.3).
Detecting and Destroying Cancer Cells in More Than One Way with Noble Metals and Different Confinement Properties on the Nanoscale *
Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Erik C. Dreaden, Mostafa A. El-Sayed
In this account, we explore the emerging applications of noble metal nanotechnologies in cancer diagnostics and therapeutics carried out by our group and by others. Many of the novel biomedical properties associated with gold and silver nanoparticles arise from confinement effects: (i) the confinement of photons within the particle which can lead to dramatic electromagnetic scattering and absorption (useful in sensing and heating applications, respectively); (ii) the confinement of molecules around the nanoparticle (useful in drug delivery); and (iii) the cellular/subcellular confinement of particles within malignant cells (such as selective, nuclear-targeted cytotoxic DNA damage by gold nanoparticles). We then describe how these confinement effects relate to specific aspects of diagnosis and treatment such as (i) laser photothermal therapy, optical scattering microscopy, and spectroscopic detection, (ii) drug targeting and delivery, and (iii) the ability of these structures to act as intrinsic therapeutic agents which can selectively perturb/inhibit cellular functions such as division. We intend to provide the reader with a unique physical and chemical perspective on both the design and application of these technologies in cancer diagnostics and therapeutics. We also suggest a framework for approaching future research in the field.
Efficacy of polyvinylpyrrolidone-capped gold nanorods against 7,12 dimethylbenz(a)anthracene-induced oviduct and endometrial cancers in albino rats
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Hend Gamal, Walid Tawfik, Hassan H El-Sayyad, Heba Mohamed Fahmy, Ahmed N. Emam, Heba A El-Ghaweet
Polycyclic aromatic hydrocarbons (PAHs) are a family of structurally related compounds and a significant class of environmental carcinogens. Both epidemiological and laboratory investigations have linked these carcinogens and associated halogenated chemicals to the development of mammary tumors. DMBA is an example of PAH that has been used to encourage tumor growth in laboratory animals (7,12-dimethylbenz[a]anthracene) [1]. Recently, the administration of DMBA to mice’s female reproductive tracts has resulted in a significant upsurge in the incidence of squamous cell carcinomas [2]. Surgery, radiation therapy, hormone therapy and chemotherapy are used concurrently or separately as part of the current endometrial cancer treatment protocol [3]. This protocol highlights the demand for novel therapeutic strategies that have been researched recently. Noble metal-based nanoparticles are created using various physical and chemical processes, and their uses in health care and remedy are unceasingly expanding [4]. The toxicity of nanoparticles made from these noble metals must be understood as concerns about human safety grow. The creation of gold nanoparticles via a bio-based method has been emphasized by life sciences researchers as being urgently essential for use in medication, health care, biolabeling, targeted medication delivery, hyperthermia and biosensors, among other applications [5]. All parameters must be studied before application in vivo for their internal use to ensure safety precautions.
Nanomaterials as drug delivery systems with antibacterial properties: current trends and future priorities
Published in Expert Review of Anti-infective Therapy, 2021
Khatereh Khorsandi, Reza Hosseinzadeh, Homa Sadat Esfahani, Saeedeh Keyvani-Ghamsari, Saeed Ur Rahman
Until now, extensive studies have been done on the biocompatibility of metal oxides and noble metals NPs both in vitro and in vivo. For instance, scientists studied the effect of Ag and Au NPs with different charge, ranging in size from 7 to 10 nm on different human lung epithelial cell types. The results showed different growth characteristics among the cell types used. NPs with a positive charge were absorbed by the cells more than NPs with a negative charge and a large percentage of them migrated to the nucleus after entering the cell. Finally, NPs induced cell death, pre-inflammatory responses, and ROS production within cells. Surface coatings of NPs also played an important role in their toxicity, so that chitosan-coated NPs increased oxidative responses inside the cell, this effect was greater on Au NPs than Ag NPs [256]. Studies have shown that metal NPs such as Si,Zn, Fe, Ti, and Ce through the production of ROS induced apoptosis in the cells [257] . ROS production is one of the effects of NPs on mammalian cells. The excessive ROS production can affect the mitochondrial respiratory chain and the structure of macromolecules. They also stimulated the endoplasmic reticulum stress and affected the folding of proteins, increasing misfolded and unfolded proteins in the cells. The combination of these changes activated the signaling pathways of inflammation, apoptosis, or necrosis in the cells [258,259] .
The biodistribution and immuno-responses of differently shaped non-modified gold particles in zebrafish embryos
Published in Nanotoxicology, 2019
M. van Pomeren, W.J.G.M. Peijnenburg, R.C. Vlieg, S.J.T. van Noort, M.G. Vijver
As a noble metal with low toxicity, gold has been an ideal material in nanomedicine for diagnostic and therapeutic purposes such as imaging agents and drug delivery systems (Khlebtsov and Dykman 2011; Truong et al. 2015; Takeuchi et al. 2017). Specifically coating/labeling the AuNPs enables researchers to guide the particles to the desired target (Black et al. 2014). What happens to the AuNP when the coating or labeling is released is hardly studied, although some studies found that the coating can change (Simpson et al. 2010) and even separate from the particles (Bogdanov et al. 2015) under in vivo conditions. Gold is found to be biocompatible (Browning et al. 2009; Takeuchi et al. 2017), and its nanoform is categorized as an active and insoluble material which promotes cellular effects and/or mobility in organisms (Arts et al. 2015). Therefore, it can be used as a platform for delivery in nanomedicine and for in vivo imaging experiments without major adverse effects. Due to their distinctive plasmonic resonances (Mesquita et al. 2017), high Rayleight scattering (Browning et al. 2009), and resistance against photo-bleaching and photo-blinking (Mesquita et al. 2017), are gold particles very suitable for a variety of imaging techniques. Additionally, gold particles can be synthesized relatively easily, with control of their size and shape (Mesquita et al. 2017). The fact that AuNPs are synthesized in different shapes, combined with their inert properties makes gold the perfect material for testing the effect of shape on particle toxicity.