Intelligent Nanomaterials for Medicine: Carrier Platforms and Targeting Strategies—State of the Art
Lajos P. Balogh in Nano-Enabled Medical Applications, 2020
Metallic nanoparticles such as iron oxide, gold, and silver have been developed and modified for use in drug delivery, magnetic separation, and diagnostic imaging [87–90]. Superparamagnetic nanoparticles (SPION) built from oxide nanoparticles, such as magnetite (Fe3O4) and maghemite (Fe2O3), exhibit particular features like ultrafine size, biocompatibility, and magnetic properties. The superparamagnetic properties become manifest when a magnetic moment is induced through the application of a magnetic field. The large magnetic moment yields a strong signal change in magnetic resonance imaging (MRI) allowing therefore sensitive detection at high resolution [91]. Another application of iron oxide nanoparticles is tumor treatment by magnetically induced hyperthermia [92]. Thanks to its chemical inertness and suited mechanical properties, gold has been used in medicine for teeth implants and is also in use in cancer radiotherapy [93]. Gold nanoparticles can be formed with core sizes ranging from 1 to 100 nm. The initial claim of absence of cytotoxicity has raised enthusiasm as an excellent drug delivery system although increasing recognition of size dependent cytotoxicity needs to be considered before their application [94, 95]. Gold nanoparticles are capable of delivering peptides, proteins nucleic acids, or small molecules. When functionalized with quaternary ammonium groups, they can bind negatively charged DNA or RNA and also protect the nucleic acids from enzymatic degradation [96].
Nano-Sized CT Contrast Agents *
Valerio Voliani in Nanomaterials and Neoplasms, 2021
Gold nanoparticles coated with Gd-chelates were used as contrast agents for CT and MRI [90]. The nanoparticles were prepared either via reduction of gold salts in the presence of thiolated chelates or by ligand exchange of citrate-coated gold nanoparticles. Functionalization of gold nanoparticles with Gd-chelates harnesses both the MR contrast effect and the CT contrast effect. The X-ray attenuation effect of gadolinium is higher than that of iodine, and the Gd-coated gold nanoparticles exhibited higher CT numbers than nanoparticles without Gd-chelates at the same gold concentration. The tumbling rate of Gd-chelates conjugated onto the nanoparticles is significantly reduced compared with free Gd-chelates, resulting in higher r1 relaxivity [91]. Gold nanorods have more available sites for conjugation of Gd-chelates due to their high surface-to-volume ratio [90c]. The measured relaxivities of Gd-coated gold nanorods were 21.3 mM−1s−1 and 1.1 × 107 mM−1s−1 on per-Gd ion basis and on per-particle basis, respectively.
X-ray Vision: Diagnostic X-rays and CT Scans
Suzanne Amador Kane, Boris A. Gelman in Introduction to Physics in Modern Medicine, 2020
Development of new contrast agents that increase the sensitivity and safety of x-ray imaging is an active interdisciplinary research area. In recent years, one of the directions has been the application of nanotechnology to manufacture contrast materials with improved properties for various x-ray diagnostic procedures. Nanotechnology is a set of methods and techniques for manipulating matter on scales of order of nanometers (1 nm = 10−9 m). An example is the use of gold nanoparticles as contrast agents. Nanoparticles are specks of matter about a hundred nanometers in size (for comparison, the diameter of a human hair is about 80,000 nm). Nanoparticles consist of a relatively small number of atoms and their size and shape can be engineered to have desired properties. Gold nanoparticles, for example, can improve contrast efficiency due to their high atomic number (Z = 79) which increases their mass attenuation coefficient compared with barium and iodine media. Studies show that gold nanoparticles can potentially improve contrast for mammography at low x-ray energy and for CT at higher energies. In addition, gold nanoparticles may reduce toxicity and increase retention time (the time the agent remains in the tissue that is being imaged). These properties are particularly useful for x-ray angiography.
A novel strategy to the formulation of carmustine and bioactive nanoparticles co-loaded PLGA biocomposite spheres for targeting drug delivery to glioma treatment and nursing care
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Shufeng Yi, Fan Yang, Cunle Jie, Guiqin Zhang
The SEM and TEM image of Cm-Au-PLGA-PSPE composites is shown in Figure 4. The TEM images of composite have shown hexagonal-shaped particles with particle size in the range of 14.8–30.4 nm. The particle size ranged between 5 and 15 nm for gold nanoparticles [31]. The average size of the Cm-Au-PLGA-PSPE composites was 24 nm. The mean size of the CS/Ag/ZnO nanocomposite as determined by SEM was between 100 and 150 nm [32]. The size of CS/ZnO composite ranges between 100 and 200nm [33]. After the preparation of Cm-Au-PLGA-PSPE composites, the amount of carmustine remaining in the supernatant was measured using a spectrophotometer. The encapsulation efficiency was determined as 85 ± 2% (Figure 5). Das et al. [34] reported that the entrapment efficiency was less than 20% for curcumin in the alginate-chitosan-pluronic composite.
Systematic determination of the relationship between nanoparticle core diameter and toxicity for a series of structurally analogous gold nanoparticles in zebrafish
Published in Nanotoxicology, 2019
Lisa Truong, Tatiana Zaikova, Brandi L. Baldock, Michele Balik-Meisner, Kimberly To, David M. Reif, Zachary C. Kennedy, James E. Hutchison, Robert L. Tanguay
In previous studies, we observed that AuNP toxicity depends on the surface chemistry, type and number of ligands, and purity (Harper et al. 2011; Schaeublin et al. 2011; Truong et al. 2017). We found that positively charged TMAT-protected 0.8 nm and 1.5 nm particles were the most toxic when compared to negatively charged or neutral AuNPs (Harper et al. 2011; Truong et al. 2013). This structure–activity relationship led us to utilize TMAT-AuNPs to investigate the impact of core diameter on toxicity. We synthesized five specific sizes of gold nanoparticles in the sub 10 nanometer range to (a) investigate a greater number of core diameters than is currently available, and to (b) test the hypothesis posed by the community that <10 nm core diameter NPs are more toxic. The developmental zebrafish assay provided sensitive and timely readouts of NP structure–bioactivity relationships in small volume (100 µL) assays in only 5 days. Additionally, this powerful model can develop normally in water from 0 to 5 days, reducing confounding factors such as aggregation and interactions with solution ions.
Green synthesis and characterization of gold nanoparticles from Pholiota adiposa and their anticancer effects on hepatic carcinoma
Published in Drug Delivery, 2022
Zhongwei Yang, Zijing Liu, Junmo Zhu, Jie Xu, Youwei Pu, Yixi Bao
The FT-IR spectra of PAP-1a and its binding efficiency to AuNPs are shown in Figure 4. A. This result demonstrated the presence of multiple functional groups. The peaks observed for the PAP-AuNPs at 3443.09 and 1636.92 cm−1, which were correspondingly assigned to the free O-H and C=C stretching modes, could arise from the PAP-1a. Chemical, electrochemical, and photolytic reduction techniques are the most prevalent ways of the reduction of gold nanoparticles (Pestov et al., 2016). The reduction involved functional groups, such as hydro sulfonyl (–SH) and aldehyde group (–CHO) (Zhang et al., 2019). The FT-IR analysis of PAP-AuNPs revealed a peak at 1636.92 cm−1, indicating the presence of esters compounds and maybe revealing the underlying mechanisms of PAP-1a that bring about the reduction of chloroauric acid to PAP-AuNPs. The EDAX result depicted the elemental composition of PAP-AuNPs (Figure 4(B)) indicating the presence of Au, C, and O, which presumably aid in the effective synthesis of PAP-AuNPs.
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