Unfolding of insulin at the surface of ZnO quantum dots

Hosseinzadeh, Ghader; Saboury, Ali Akbar; Moosavi-Movahedi, Ali Akbar

doi:10.1016/j.ijbiomac.2016.01.075

Cited by 19 publications

(13 citation statements)

References 53 publications

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“…The size influences the stability of the particles, since small particles lead to a more discrepant relation between the particle radius and the exciton Bohr radius (i.e., the electron-hole pairthe distance between the valence band hole and the electron's position in conduction band when a bulk semiconductor is excited; Zhang et al 2014). The size of the quantum dots is smaller than twice the size of the exciton Bohr radius of their bulk material (Hosseinzadeh et al 2016). When the particle radius is smaller than Bohr radius, electrons and hole suffer quantum confinement, turning the particle stable in a controlled environment.…”

Section: Discussionmentioning

confidence: 99%

“…Quantum dots are inorganic particles about 1 to 10 nm, obtained via semiconductor materials (Singh and Kumar 2006). These nanocrystals, also known as "artificial atoms," are used for applications in materials for engineering (Matsuyama et al 2012;Feng et al 2015;Padovani et al 2015) and bioengineering (Khani et al 2011;Bilan et al 2015;Hosseinzadeh et al 2016) due to the fluorescence and suspension in colloidal medium attributed to quantum confinement (Matsuyama et al 2012). Consequently, quantum dots do not agglomerate when in equilibrium.…”

Section: Introductionmentioning

confidence: 99%

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Quantum Dots as Nonagglomerated Nanofillers for Adhesive Resins

et al. 2016

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Nanoparticles used in adhesive resins are prone to agglomeration, turning the material susceptible to physical failure. Quantum dots are nonagglomerated inorganic nanoparticles (1 to 10 nm) when in equilibrium. The aim of the present study was to synthesize and characterize zinc oxide quantum dots (ZnO) and to develop and evaluate an adhesive resin with the addition of ZnO. ZnO were formulated by self-organization in chemical reaction with isopropanol and added to 2-hydroxyethyl methacrylate (HEMA). HEMA containing ZnO was used for the experimental group and neat HEMA for the control group. Mean ZnO diameter was evaluated in isopropanol and in HEMA by ultraviolet-visible spectroscopy. The adhesives were evaluated for degree of conversion ( n = 5), softening in solvent ( n = 5), ultimate tensile strength ( n = 5), microtensile bond strength ( n = 20) at 24 h and after 6 mo, SEM-EDS (scanning electron microscopy-energy-dispersive x-ray spectroscopy; n = 3), and superresolution confocal microscopy ( n = 3). Data of microtensile bond strength after 6 mo and Knoop hardness after solvent immersion were evaluated by paired t test with a 0.05 level of significance. The other data were evaluated by independent t test with a 0.05 level of significance. Ultraviolet-visible spectroscopy indicated that the mean ZnOQD diameter remained stable in isopropanol and in HEMA (1.19 to 1.24 nm). Fourier transform infrared spectroscopy analysis showed the peak corresponding to zinc and oxygen bond (440 cm). The experimental group achieved a higher degree of conversion as compared with the control group and presented dentin/adhesive interface stability after 6 mo without altering other properties tested. SEM-EDS indicated 1.54 ± 0.46 wt% of zinc, and the superresolution confocal microscopy indicated nonagglomerated nanoparticles with fluorescence blinking in the polymerized adhesive. The findings of this study showed a possible and reliable method to formulate composites with nonagglomerated nanoscale fillers, shedding light on the nanoparticle agglomeration concern.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantum Dots as Nonagglomerated Nanofillers for Adhesive Resins

et al. 2016

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“…In biomedical applications of QDs, such as cancer diagnosis, in order to detection of various diseases the QDs as diagnostic agents are injected directly into the blood vessel and carried by blood to their targets (cancerous cells). Inside of the blood vessel, by exposure of the blood proteins to QDs, these proteins may be adsorbed on the QDs surface, leading to the formation of the protein-QDs conjugates [13][14][15][16]. The attached proteins at the surface of QDs (protein corona) undergo some structural changes, and produce the protein aggregates or some toxic proteins [17,18].…”

Section: Introductionmentioning

confidence: 99%

Interaction of insulin with colloidal ZnS quantum dots functionalized by various surface capping agents

Hosseinzadeh

Farniya

Keihan

et al. 2017

Materials Science and Engineering: C

Self Cite

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Interaction of quantum dots (QDs) and proteins strongly influenced by the surface characteristics of the QDs at the protein-QD interface. For a precise control of these surface-related interactions, it is necessary to improve our understanding in this field. In this regard, in the present work, the interaction between the insulin and differently functionalized ZnS quantum dots (QDs) were studied. The ZnS QDs were functionalized with various functional groups of hydroxyl (OH), carboxyl (COOH), amine (NH), and amino acid (COOH and NH). The effect of surface hydrophobicity was also studied by changing the alkyl-chain lengths of mercaptocarboxylic acid capping agents. The interaction between insulin and the ZnS QDs were investigated by fluorescence quenching, synchronous fluorescence, circular dichroism (CD), and thermal aggregation techniques. The results reveal that among the studied QDs, mercaptosuccinic acid functionalized QDs has the strongest interaction (∆G=-51.50kJ/mol at 310K) with insulin, mercaptoethanol functionalized QDs destabilize insulin by increasing the beta-sheet contents, and only cysteine functionalized QDs improves the insulin stability by increasing the alpha-helix contents of the protein, and. Our results also indicate that by increasing the alkyl-chain length of capping agents, due to an increase in hydrophobicity of the QDs surface, the beta-sheet contents of insulin increase which results in the enhancement of insulin instability.

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“…The ordered aggregation or assembly process in general is characterized by an alteration from the native fold toward different conformers with high beta-sheet content. In the case of insulin, for example the native form is composed of 95% alpha-helical structures, whereas in the aggregate form, a clear transition in the secondary structure was observed toward a single peak ranging from 215 to 220 nm indicative of beta-sheet secondary structures similar to the aggregate state observed with IgG/IgY (Hosseinzadeh et al, 2016 ). An evident increase in the amplitude of a negative peak (215 and 220 nm, Figure 2 ) was obtained for the self-assembled Igs (pH 2), compared to their native state (pH 7), which indicates a shift in the secondary structure toward a predominantly beta-sheet structure (Jiang et al, 2012 ).…”

Section: Discussionmentioning

confidence: 98%

Formation of multimeric antibodies for self-delivery of active monomers

Dekel

Machluf²,

Gefen

et al. 2017

Drug Delivery

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Proteins and peptides have been used as drugs for almost a century. Technological advances in the past 30 years have enabled the production of pure, stable proteins in vast amounts. In contrast, administration of proteins based on their native active conformation (and thus necessitating the use of subcutaneous injections) has remained solely unchanged. The therapeutic anti-HER2 humanized monoclonal immunoglobulin (IgG) Trastuzumab (Herceptin) is a first line of the treatment for breast cancer. Chicken IgY is a commercially important polyclonal antibody (Ab). These Abs were examined for their ability to self-assemble and form ordered aggregates, by several biophysical methods. Atomic force microscopy analyses revealed the formation of multimeric nanostructures. The biological activity of multimeric IgG or IgY particles was retained and restored, in a dilution/time-dependent manner. IgG activity was confirmed by a binding assay using HER2 + human breast cancer cell line, SKBR3, while IgY activity was confirmed by ELISA assay using the VP2 antigen. Competition assay with native Herceptin antibodies demonstrated that the binding availability of the multimer formulation remained unaffected. Under long incubation periods, IgG multimers retained five times more activity than native IgG. In conclusion, the multimeric antibody formulations can serve as a storage depositories and sustained-release particles. These two important characteristics make this formulation promising for future novel administration protocols and altogether bring to light a different conceptual approach for the future use of therapeutic proteins as self-delivery entities rather than conjugated/encapsulated to other bio-compounds.

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Unfolding of insulin at the surface of ZnO quantum dots

Cited by 19 publications

References 53 publications

Quantum Dots as Nonagglomerated Nanofillers for Adhesive Resins

Quantum Dots as Nonagglomerated Nanofillers for Adhesive Resins

Interaction of insulin with colloidal ZnS quantum dots functionalized by various surface capping agents

Formation of multimeric antibodies for self-delivery of active monomers

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