scholarly journals Hydroxyethyl Starch-Based Functionalization of Gold Nanorods: A Possible Alternative to Polyethylene Glycol as a Surface Modifier

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Asmita Pandey ◽  
Sujan Khadka ◽  
Ying Wan
Keyword(s):  
Polyethylene Glycol ◽  
Hydroxyethyl Starch ◽  
Heat Generation ◽  
Gold Nanorods ◽  
Half Life ◽  
Colloidal Stability ◽  
Mononuclear Phagocyte ◽  
Mononuclear Phagocyte System ◽  
Promising Alternative ◽  
Surface Modifier

PEGylation refers to the process of functionalizing nanoparticles with polyethylene glycol (PEG) to avoid unspecific uptake by the mononuclear phagocyte system and prolong the circulation half-life of nanomedicines. Immunogenicity and nonbiodegradability are the major limitations in PEGylation that can be resolved by substituting PEG with biofriendly polymers, such as hydroxyethyl starch (HES). In the current study, thiolated hydroxyethyl starch (HES-SH, 130/0.4) was harnessed to stabilize gold nanorods (AuNRs) and compared with PEG-SH-coated AuNRs at different aspects of characterization and photothermal analysis. Our results confirm that AuNRs were functionalized successfully with both HES-SH and PEG-SH, where the initial spectra and colloidal stability of gold nanorods were restored after functionalization. In addition, the photothermal conversion stability of gold nanorods was maintained during both HESylation and PEGylation without affecting the heat generation. In summary, we presume that HES-SH can be used as a surface modifier to stabilize gold nanorods and might be used as a promising alternative to PEG.

The influence of polyethylene glycol passivation on the surface plasmon resonance induced photothermal properties of gold nanorods

Nanoscale ◽  
2018 ◽  
Vol 10 (28) ◽  
pp. 13684-13693 ◽  
Author(s):  
Ramesh Marasini ◽  
Arunkumar Pitchaimani ◽  
Tuyen Duong Thanh Nguyen ◽  
Jeffrey Comer ◽  
Santosh Aryal
Keyword(s):  
Surface Plasmon Resonance ◽  
Heat Conduction ◽  
Polyethylene Glycol ◽  
Surface Plasmon ◽  
Gold Nanorods ◽  
Plasmon Resonance ◽  
Colloidal Stability ◽  
Surface Passivation ◽  
Liquid Interface ◽  
Comprehensive Study

This comprehensive study suggested an optimum PEG polymer length of 5 kDa is advantageous for surface passivation and colloidal stability of AuNRs, which also maximizes the heat conduction from the nanorod–liquid interface to the surroundings, thereby, enhancing photothermal efficiency.

Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3353-3360
Author(s):  
Susana Helena Arellano Ramírez ◽  
Perla García Casillas ◽  
Christian Chapa González
Keyword(s):  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Infrared Spectrometry ◽  
Ammonium Bromide ◽  
Chloroauric Acid ◽  
Vis Spectroscopy ◽  
Seed Mediated ◽  
Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

The Impact of Bioconjugation on the Interfacial Activity of a Protein Biosurfactant

2018 ◽  
Author(s):  
Hossam H Tayeb ◽  
Marina Stienecker ◽  
Anton Middelberg ◽  
Frank Sainsbury
Keyword(s):  
Polyethylene Glycol ◽  
Colloidal Stability ◽  
Point Mutations ◽  
Pharmaceutical Formulations ◽  
Industrial Processes ◽  
Parent Molecule ◽  
Site Specific ◽  
Interfacial Activity ◽  
Surface Active ◽  
The Impact

Biosurfactants, are surface active molecules that can be produced by renewable, industrially scalable biologic processes. DAMP4, a designer biosurfactant, enables the modification of interfaces via genetic or chemical fusion to functional moieties. However, bioconjugation of addressable amines introduces heterogeneity that limits the precision of functionalization as well as the resolution of interfacial characterization. Here we designed DAMP4 variants with cysteine point mutations to allow for site-specific bioconjugation. The DAMP4 variants were shown to retain the structural stability and interfacial activity characteristic of the parent molecule, while permitting efficient and specific conjugation of polyethylene glycol (PEG). PEGylation results in a considerable reduction on the interfacial activity of both single and double mutants. Comparison of conjugates with one or two conjugation sites shows that both the number of conjugates as well as the mass of conjugated material impacts the interfacial activity of DAMP4. As a result, the ability of DAMP4 variants with multiple PEG conjugates to impart colloidal stability on peptide-stabilized emulsions is reduced. We suggest that this is due to constraints on the structure of amphiphilic helices at the interface. Specific and efficient bioconjugation permits the exploration and investigation of the interfacial properties of designer protein biosurfactants with molecular precision. Our findings should therefore inform the design and modification of biosurfactants for their increasing use in industrial processes, and nutritional and pharmaceutical formulations.

scholarly journals African Trypanosomiasis-Associated Anemia: The Contribution of the Interplay between Parasites and the Mononuclear Phagocyte System

2018 ◽  
Vol 9 ◽  
Author(s):  
Benoit Stijlemans ◽  
Patrick De Baetselier ◽  
Stefan Magez ◽  
Jo A. Van Ginderachter ◽  
Carl De Trez
Keyword(s):  
Mononuclear Phagocyte ◽  
Mononuclear Phagocyte System ◽  
African Trypanosomiasis
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