scholarly journals Physicochemical and Biological Properties of Graphene-Oxide-Coated Metallic Materials

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5752
Author(s):  
Aleksandra Poniatowska ◽  
Paulina Anna Trzaskowska ◽  
Maciej Trzaskowski ◽  
Tomasz Ciach
Keyword(s):  
Graphene Oxide ◽  
Biological Properties ◽  
Negative Control ◽  
L929 Cells ◽  
Potential Applications ◽  
Direct Cell ◽  
Future Potential ◽  
The Stability ◽  
Modified Hummers Method ◽  
Modification Of The Surface

In this article, we present graphene oxide (produced by a modified Hummers’ method) coatings obtained using two different methods: electrophoretic deposition on 316L stainless steel and chemical modification of the surface of gold applied to the steel. The coating properties were characterized by microscopic and spectrometric techniques. The contact angle was also determined, ranging from 50° to 70°. Our results indicated that GO coatings on steel and gold were not toxic towards L929 cells in a direct cell adhesion test—on all tested materials, it was possible to observe the growth of L929 cells during 48 h of culture. The lack of toxic effect on cells was also confirmed in two viability tests, XTT and MTT. For most of the tested materials, the cell viability was above 70%. They showed that the stability of the coating is the crucial factor for such GO coatings, and prove that GO in the form of coating is non-toxic; however, it can show toxicity if detached from the surface. The obtained materials also did not show any hemolytic properties, as the percentage of hemolysis was on the level of the negative control, which is very promising in the light of future potential applications.

Chitosan-Stabilized Oil-in-Water Nanoemulsions

2022 ◽  
pp. 44-58
Author(s):  
Viktoria Milkova
Keyword(s):  
Physicochemical Characteristics ◽  
Biological Properties ◽  
Precise Control ◽  
Theoretical Approaches ◽  
Natural Polysaccharide ◽  
Oil In Water ◽  
Degree Of Acetylation ◽  
Key Factor ◽  
Potential Applications ◽  
The Stability

Chitosan is a natural polysaccharide and emulsifier that can ensure a significant emulsion stability at suitable pH, ionic strength, composition, concentration, or thermal processing. The evaluation of the electrokinetic properties is a key factor in investigation of the stability of the nanoemulsions with a view to their potential applications in bionanotechnology. Consequently, the precise control over the physicochemical characteristics of chitosan (degree of acetylation, DA and molecular weight, Mw) can provide a high stability and specific biological properties of the developed functional structures. The chapter is focused on the interpretation of the electrokinetic response from nanoemulsion stabilized by adsorption of chitosan (as a polyelectrolyte or uncharged polymer) by using appropriate theoretical approaches.

scholarly journals Graphene Oxide: Opportunities and Challenges in Biomedicine

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1083
Author(s):  
Pariya Zare ◽  
Mina Aleemardani ◽  
Amelia Seifalian ◽  
Zohreh Bagher ◽  
Alexander M. Seifalian
Keyword(s):  
Graphene Oxide ◽  
Biomedical Applications ◽  
Volume Ratio ◽  
Biological Properties ◽  
Light Weight ◽  
Human Organs ◽  
Biological Features ◽  
Proliferation And Differentiation ◽  
Future Potential

Desirable carbon allotropes such as graphene oxide (GO) have entered the field with several biomedical applications, owing to their exceptional physicochemical and biological features, including extreme strength, found to be 200 times stronger than steel; remarkable light weight; large surface-to-volume ratio; chemical stability; unparalleled thermal and electrical conductivity; and enhanced cell adhesion, proliferation, and differentiation properties. The presence of functional groups on graphene oxide (GO) enhances further interactions with other molecules. Therefore, recent studies have focused on GO-based materials (GOBMs) rather than graphene. The aim of this research was to highlight the physicochemical and biological properties of GOBMs, especially their significance to biomedical applications. The latest studies of GOBMs in biomedical applications are critically reviewed, and in vitro and preclinical studies are assessed. Furthermore, the challenges likely to be faced and prospective future potential are addressed. GOBMs, a high potential emerging material, will dominate the materials of choice in the repair and development of human organs and medical devices. There is already great interest among academics as well as in pharmaceutical and biomedical industries.

scholarly journals Extraordinary thermal behavior of graphene oxide in air for electrode applications

2021 ◽  
Author(s):  
Joong Tark Han ◽  
Joon Young Cho ◽  
Jeong Hoon Kim
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Physical Properties ◽  
Thermal Behavior ◽  
Stability Of Solution ◽  
Exfoliated Graphene ◽  
Potential Applications ◽  
Thermal Stability Of

The thermal stability of solution-exfoliated graphene oxide (GO) in air is one of the most important physical properties influencing its potential applications. To date, majority of the GO prepared by...

scholarly journals A pH-Responsive Foam Formulated with PAA/Gemini 12-2-12 Complexes

2021 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Hernán Martinelli ◽  
Claudia Domínguez ◽  
Marcos Fernández Leyes ◽  
Sergio Moya ◽  
Hernán Ritacco
Keyword(s):  
Surface Tension ◽  
Dynamic Surface Tension ◽  
Foam Formation ◽  
Ph Responsive ◽  
Dynamic Surface ◽  
X Ray ◽  
Equilibrium Surface Tension ◽  
Potential Applications ◽  
The Stability ◽  
Air Interfaces

In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics.

scholarly journals Lerf–Klinowski-type models of graphene oxide and reduced graphene oxide are robust in analyzing non-covalent functionalization with porphyrins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexandra Siklitskaya ◽  
Ewelina Gacka ◽  
Daria Larowska ◽  
Marta Mazurkiewicz-Pawlicka ◽  
Artur Malolepszy ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Excited States ◽  
Reduced Graphene ◽  
Simulation Protocol ◽  
Potential Applications ◽  
H 26 ◽  
High Level ◽  
Experimental And Theoretical Studies ◽  
Low Solubility

AbstractGraphene-based nanohybrids are good candidates for various applications. However, graphene exhibits some unwanted features such as low solubility in an aqueous solution or tendency to aggregate, limiting its potential applications. On the contrary, its derivatives, such as graphene oxide (GO) and reduced graphene oxide (RGO), have excellent properties and can be easily produced in large quantities. GO/RGO nanohybrids with porphyrins were shown to possess great potential in the field of photocatalytic hydrogen production, pollutant photodegradation, optical sensing, or drug delivery. Despite the rapid progress in experimental research on the porphyrin-graphene hybrids some fundamental questions about the structures and the interaction between components in these systems still remain open. In this work, we combine detailed experimental and theoretical studies to investigate the nature of the interaction between the GO/RGO and two metal-free porphyrins 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) and 5,10,15,20-tetrakis(4-hydroxyphenyl) porphyrin (TPPH)]. The two porphyrins form stable nanohybrids with GO/RGO support, although both porphyrins exhibited a slightly higher affinity to RGO. We validated finite, Lerf–Klinowski-type (Lerf et al. in J Phys Chem B 102:4477, 1998) structural models of GO ($$\hbox {C}_{59}\hbox {O}_{26}\hbox {H}_{26}$$ C 59 O 26 H 26 ) and RGO ($$\hbox {C}_{59}\hbox {O}_{17}\hbox {H}_{26}$$ C 59 O 17 H 26 ) and successfully used them in ab initio absorption spectra simulations to track back the origin of experimentally observed spectral features. We also investigated the nature of low-lying excited states with high-level wavefunction-based methods and shown that states’ density becomes denser upon nanohybrid formation. The studied nanohybrids are non-emissive, and our study suggests that this is due to excited states that gain significant charge-transfer character. The presented efficient simulation protocol may ease the properties screening of new GO/RGO-nanohybrids.

scholarly journals Anthocyanins Recovered from Agri-Food By-Products Using Innovative Processes: Trends, Challenges, and Perspectives for Their Application in Food Systems

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2632
Author(s):  
Henrique Silvano Arruda ◽  
Eric Keven Silva ◽  
Nayara Macêdo Peixoto Araujo ◽  
Gustavo Araujo Pereira ◽  
Glaucia Maria Pastore ◽  
...  
Keyword(s):  
Food Systems ◽  
Food Industry ◽  
Biological Properties ◽  
Extraction Techniques ◽  
Naturally Occurring ◽  
Current Review ◽  
Natural Colorants ◽  
Conventional Extraction ◽  
The Stability ◽  
By Products

Anthocyanins are naturally occurring phytochemicals that have attracted growing interest from consumers and the food industry due to their multiple biological properties and technological applications. Nevertheless, conventional extraction techniques based on thermal technologies can compromise both the recovery and stability of anthocyanins, reducing their global yield and/or limiting their application in food systems. The current review provides an overview of the main innovative processes (e.g., pulsed electric field, microwave, and ultrasound) used to recover anthocyanins from agri-food waste/by-products and the mechanisms involved in anthocyanin extraction and their impacts on the stability of these compounds. Moreover, trends and perspectives of anthocyanins’ applications in food systems, such as antioxidants, natural colorants, preservatives, and active and smart packaging components, are addressed. Challenges behind anthocyanin implementation in food systems are displayed and potential solutions to overcome these drawbacks are proposed.

scholarly journals Thermally Stimulated Desorption Optical Fiber-Based Interrogation System: An Analysis of Graphene Oxide Layers’ Stability

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 70
Author(s):  
Maria Raposo ◽  
Carlota Xavier ◽  
Catarina Monteiro ◽  
Susana Silva ◽  
Orlando Frazão ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Layer By Layer ◽  
Film Stability ◽  
A Value ◽  
Device Reliability ◽  
Sensor Devices ◽  
Lbl Films ◽  
The Stability

Thin graphene oxide (GO) film layers are being widely used as sensing layers in different types of electrical and optical sensor devices. GO layers are particularly popular because of their tuned interface reflectivity. The stability of GO layers is fundamental for sensor device reliability, particularly in complex aqueous environments such as wastewater. In this work, the stability of GO layers in layer-by-layer (LbL) films of polyethyleneimine (PEI) and GO was investigated. The results led to the following conclusions: PEI/GO films grow linearly with the number of bilayers as long as the adsorption time is kept constant; the adsorption kinetics of a GO layer follow the behavior of the adsorption of polyelectrolytes; and the interaction associated with the growth of these films is of the ionic type since the desorption activation energy has a value of 119 ± 17 kJ/mol. Therefore, it is possible to conclude that PEI/GO films are suitable for application in optical fiber sensor devices; most importantly, an optical fiber-based interrogation setup can easily be adapted to investigate in situ desorption via a thermally stimulated process. In addition, it is possible to draw inferences about film stability in solution in a fast, reliable way when compared with the traditional ones.

scholarly journals The Structure–Properties–Cytotoxicity Interplay: A Crucial Pathway to Determining Graphene Oxide Biocompatibility

2021 ◽  
Vol 22 (10) ◽  
pp. 5401
Author(s):  
Marta Dziewięcka ◽  
Mirosława Pawlyta ◽  
Łukasz Majchrzycki ◽  
Katarzyna Balin ◽  
Sylwia Barteczko ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Defense Mechanisms ◽  
Physicochemical Analysis ◽  
Experimental Models ◽  
Acheta Domesticus ◽  
Synthesis Process ◽  
Synthesis Methods ◽  
Toxicity Potential ◽  
Potential Applications

Interest in graphene oxide nature and potential applications (especially nanocarriers) has resulted in numerous studies, but the results do not lead to clear conclusions. In this paper, graphene oxide is obtained by multiple synthesis methods and generally characterized. The mechanism of GO interaction with the organism is hard to summarize due to its high chemical activity and variability during the synthesis process and in biological buffers’ environments. When assessing the biocompatibility of GO, it is necessary to take into account many factors derived from nanoparticles (structure, morphology, chemical composition) and the organism (species, defense mechanisms, adaptation). This research aims to determine and compare the in vivo toxicity potential of GO samples from various manufacturers. Each GO sample is analyzed in two concentrations and applied with food. The physiological reactions of an easy model Acheta domesticus (cell viability, apoptosis, oxidative defense, DNA damage) during ten-day lasting exposure were observed. This study emphasizes the variability of the GO nature and complements the biocompatibility aspect, especially in the context of various GO-based experimental models. Changes in the cell biomarkers are discussed in light of detailed physicochemical analysis.

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