scholarly journals Conjugation with gold nanoparticles improves the stability of the KT2 peptide and maintains its anticancer properties

RSC Advances ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 319-325
Author(s):  
Pornsuda Maraming ◽  
Jureerut Daduang ◽  
James Chen Yong Kah
Keyword(s):  
Gold Nanoparticles ◽  
Proteolytic Enzymes ◽  
Anticancer Properties ◽  
Therapeutic Peptides ◽  
The Stability

One of the major weaknesses of therapeutic peptides is their sensitivity to degradation by proteolytic enzymes in vivo.

scholarly journals Surface Adsorption of the Alpha-Emitter Astatine-211 to Gold Nanoparticles Is Stable In Vivo and Potentially Useful in Radionuclide Therapy

2021 ◽  
Vol 2 (4) ◽  
pp. 196-207
Author(s):  
Emanuel Sporer ◽  
Christian B. M. Poulie ◽  
Sture Lindegren ◽  
Emma Aneheim ◽  
Holger Jensen ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Adsorption ◽  
Radiochemical Yield ◽  
Gold Surface ◽  
Mouse Serum ◽  
Control Group ◽  
Alpha Emitter ◽  
Before And After ◽  
The Stability

Targeted α-therapy (TAT) can eradicate tumor metastases while limiting overall toxicity. One of the most promising α-particle emitters is astatine-211 (211At). However, 211At-carbon bonds are notoriously unstable in vivo and no chelators are available. This hampers its adoption in TAT. In this study, the stability of 211At on the surface of gold nanoparticles (AuNPs) was investigated. The employed AuNPs had sizes in the 25–50 nm range. Radiolabeling by non-specific surface-adsorption in >99% radiochemical yield was achieved by mixing 211At and AuNPs both before and after polyethylene glycol (PEG) coating. The resulting 211At-AuNPs were first challenged by harsh oxidation with sodium hypochlorite, removing roughly 50% of the attached 211At. Second, incubation in mouse serum followed by a customized stability test, showed a stability of >95% after 4 h in serum. This high stability was further confirmed in an in vivo study, with comparison to a control group of free 211At. The AuNP-associated 211At showed low uptake in stomach and thyroid, which are hallmark organs of uptake of free 211At, combined with long circulation and high liver and spleen uptake, consistent with nanoparticle biodistribution. These results support that gold surface-adsorbed 211At has high biological stability and is a potentially useful delivery system in TAT.

scholarly journals Nanoparticles Mediated Protein Stability in Comparison with Osmolytes: in vivo Approach

2021 ◽  
Vol 33 (6) ◽  
pp. 1433-1438
Author(s):  
R. Verma ◽  
N. Singh ◽  
P. Chaudhuri (Chattopadhyay)
Keyword(s):  
Gold Nanoparticles ◽  
Dihydrofolate Reductase ◽  
Three Dimensional ◽  
Cellular Level ◽  
Dimensional Structure ◽  
Important Group ◽  
Unfolded State ◽  
The Status ◽  
The Stability

The native three-dimensional structure of protein is quite unstable under critical destabilizing conditions. In order to enhance the stability and activity for a proper folded environment of a protein, many stabilizing materials are added such as nanoparticles and osmolytes to an unfolded state of protein. Osmolytes are the important group of molecules which are engaged by the cell as an adaption in the severe conditions. In this communication, a comparative in vivo study is reported for imparting the status of stability and folding ability of zebrafish dihydrofolate reductase (zDHFR) protein with gold nanoparticles and various osmolytes (glycerol, glucose and betain). Present observations revealed that the interaction of gold nanoparticles (AuNPs) with bacteria at the cellular level helps in maintaining the stability of protein more effectively than osmolytes which could be used for many biological and pharmacological approaches although glycerol as an osmolyte also stabilizes the protein at a significant level.

scholarly journals Gold Nanoparticles: Synthesis, Stability Test, and Application for the Rice Growth

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Aiwu Wang ◽  
Hoi Pong Ng ◽  
Yi Xu ◽  
Yuyu Li ◽  
Yuhong Zheng ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Optical Properties ◽  
Rice Growth ◽  
Bulk Solid ◽  
Significant Difference ◽  
Nanoparticles Synthesis ◽  
Different Shapes ◽  
The Stability

In today’s science, with the use of nanotechnology, nanomaterials, which behave very differently from the bulk solid, can be made. One of the capable uses of nanomaterials is bioapplications which make good use of the specific properties of nanoparticles. However, since the nanoparticles will be used bothin-vivoandin-vitro, their stability is an important issue to the scientists, concern. In this dissertation, we are going to test the stability of gold nanoparticles in a number of media including the biocompatible medium and their behaviors will be illustrated in terms of optical properties change and aggregation degree. Herein, we report the synthesis of gold nanoparticles of different shapes and applications for the rice growth with significant difference. The gold nanoparticles can inhibit the elongation of rice root without inhibiting the germination of rice seeds.

scholarly journals Availability of Guanitoxin in Water Samples Containing Sphaerospermopsis torques-reginae Cells Submitted to Dissolution Tests

2020 ◽  
Vol 13 (11) ◽  
pp. 402
Author(s):  
Kelly Fernandes ◽  
Humberto Ferraz ◽  
Fanny Vereau ◽  
Ernani Pinto
Keyword(s):  
Proteolytic Enzymes ◽  
Intestinal Content ◽  
Gastric Fluid ◽  
Simulated Gastric Fluid ◽  
P Value ◽  
Dissolution Tests ◽  
Intestinal Fluids ◽  
High Concentrations ◽  
The Stability

Guanitoxin (GNT) is a potent neurotoxin produced by freshwater cyanobacteria that can cause the deaths of wild and domestic animals. Through reports of animal intoxication by cyanobacteria cells that produce GNT, this study aimed to investigate the bio-accessibility of GNT in simulated solutions of the gastrointestinal content in order to understand the process of toxicosis promoted by GNT in vivo. Dissolution tests were conducted with a mixture of Sphaerospermopsis torques-reginae (Cyanobacteria; Nostocales) cultures (30%) and gastrointestinal solutions with and without proteolytic enzymes (70%) at a temperature of 37 °C and rotation at 100 rpm for 2 h. The identification of GNT was performed by LC-QqQ-MS/MS through the transitions [M + H]+m/z 253 > 58 and [M + H]+m/z 253 > 159, which showed high concentrations of GNT in simulated gastric fluid solutions (p-value < 0.001) in comparison to simulated solutions of intestinal content. The gastric solution with pepsin promoted the stability of GNT (p-value < 0.05) compared to the simulated solution of gastric fluid at the same pH without the enzyme. However, the results showed that GNT is also available in intestinal fluids for a period of 2 h, and solutions containing the pancreatin enzyme influenced the bio-accessibility of the toxin more compared to the intestinal medium without enzyme (p-value < 0.05). Therefore, the bio-accessibility of the toxin must be considered both in the stomach and in the intestine, and may help in the diagnosis and prediction of exposure and risk in vivo through the oral ingestion of GNT-producing cyanobacteria cells.

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

Dosimetry and Radioenhancement Comparison of Gold Nanoparticles in Kilovoltage and Megavoltage Radiotherapy using MAGAT Polymer Gel Dosimeter

2019 ◽  
Vol 9 (2Apr) ◽  
Author(s):  
S Farahani ◽  
N Riyahi Alam ◽  
S Haghgoo ◽  
M Khoobi ◽  
Gh Geraily ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
3D Visualization ◽  
Energy Levels ◽  
Polymer Gel ◽  
External Radiotherapy ◽  
Dose Enhancement ◽  
Internal Radiotherapy ◽  
Boost Radiotherapy

Background: Numerous unique characteristics of the nanosized gold, including high atomic number, low toxicity, and high biocompatibility make it one of the most appropriate nanostructures to boost radiotherapy efficacy. Many in-vivo and in-vitro investigations have indicated that gold nanoparticles (AuNPs) can significantly increase tumor injuries in low kilovoltage radiotherapy. While deep-lying tumors require much higher energy levels with greater penetration power, and investigations carried out in megavoltage energy range show contradictory results.Objective: In this study, we quantitatively assess and compare dose enhancement factors (DEFs) obtained through AuNPs under radiation of Cobalt-60 source (1.25MeV) versus Iridium-192 source (0.380 KeV) using MAGAT gel dosimeter.Material and Methods: MAGAT polymer gel in both pure and combined with 0.2 mM AuNPs was synthesized. In order to quantify the effect of energy on DEF, irradiation was carried out by Co-60 external radiotherapy and Ir-192 internal radiotherapy. Finally, readings of irradiated and non-irradiated gels were performed by MR imaging.Result: The radiation-induced R2 (1/T2) changes of the gel tubes doped with AuNPs compared to control samples, upon irradiation of beams released by Ir-192 source showed a significant dose enhancement (15.31% ±0.30) relative to the Co-60 external radiotherapy (5.85% ±0.14).Conclusion: This preliminary study suggests the feasibility of using AuNPs in radiation therapy (RT), especially in low-energy sources of brachytherapy. In addition, MAGAT polymer gel, as a powerful dosimeter, could be used for 3D visualization of radiation dose distribution of AuNPs in radiotherapy.

Vitamin D as potential therapeutic anticancer agent

2018 ◽  
pp. 1-3
Keyword(s):  
Vitamin D ◽  
Anticancer Activity ◽  
Anticancer Agent ◽  
Antitumor Agents ◽  
Metastatic Potential ◽  
Anticancer Properties ◽  
Chemotherapy Agents

The role of vitamin D is implicated in carcinogenesis through numerous biological processes like induction of apoptosis, modulation of immune system inhibition of inflammation and cell proliferation and promotion of cell differentiation. Its use as additional adjuvant drug with cancer treatment may be novel combination for improved outcome of different cancers. Numerous preclinical, epidemiological and clinical studies support the role of vitamin D as an anticancer agent. Anticancer properties of vitamin D have been studied widely (both in vivo and in vitro) among various cancers and found to have promising results. There are considerable data that indicate synergistic potential of calcitriol and antitumor agents. Possible mechanisms for modulatory anticancer activity of vitamin D include its antiproliferative, prodifferentiating, and anti-angiogenic and apoptic properties. Calcitriol reduces invasiveness and metastatic potential of many cancer cells by inhibiting angiogenesis and regulating expression of the key molecules involved in invasion and metastasis. Anticancer activity of vitamin D is synergistic or additive with the antineoplastic actions of several drugs including cytotoxic chemotherapy agents like paclitaxel, docetaxel, platinum base compounds and mitoxantrone. Benefits of addition of vitamin D should be weighed against the risk of its toxicity.

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