Derivatives of Graphene Oxide as Potential Drug Carriers

From Design to Study of Liposome-Driven Drug Release Part 1: Impact of Temperature and pH on Environment

The marketed drug Doxorubicin (DOX) and the promising anti-cancer agent 9-(N-piperazinyl)-5-methyl-12(H)-quino[3,4-b][1,4]benzothiazinium chloride (9-PBThACl) were used to prepare and compare a range of liposomal delivery systems based on dipalmitoylphosphatidylcholine (DPPC). Liposome-assisted drug release was examined using the spectrophotometric method. In order to provide in vitro release characteristics of liposomal conjugates (L_DPPC/drug vs. L_{DPPC/drug/drug}) as well as to evaluate the impact of temperature and pH buffering on the conformation/polarity of the phospholipid bilayer, the encapsulation efficiency of the liposomes entrapping 9-PBThACl and DOX was calculated. In fact, some competition between the investigated molecules was noticed during the entrapment process because relatively high values of the encapsulation efficiency were observed only for the liposomal complexes containing one trapped drug molecule. An averaged absorbance value enabled us to indicate the pH value of the environment (pH ≈ 6.8), at which the physicochemical property profiles of the liposomal complexes were noticeably changed. Moreover, the operational factors limiting the drug release kinetics from the produced liposomes were mathematically modeled. First-order and Bhaskas models ensured satisfactory compliance with the experimental data for the liposomal complexes buffered at pH values of 5.50, 6.00, and 7.40, respectively.

Advances in Biologically Applicable Graphene-Based 2D Nanomaterials

Climate change and increasing contamination of the environment, due to anthropogenic activities, are accompanied with a growing negative impact on human life. Nowadays, humanity is threatened by the increasing incidence of difficult-to-treat cancer and various infectious diseases caused by resistant pathogens, but, on the other hand, ensuring sufficient safe food for balanced human nutrition is threatened by a growing infestation of agriculturally important plants, by various pathogens or by the deteriorating condition of agricultural land. One way to deal with all these undesirable facts is to try to develop technologies and sophisticated materials that could help overcome these negative effects/gloomy prospects. One possibility is to try to use nanotechnology and, within this broad field, to focus also on the study of two-dimensional carbon-based nanomaterials, which have excellent prospects to be used in various economic sectors. In this brief up-to-date overview, attention is paid to recent applications of graphene-based nanomaterials, i.e., graphene, graphene quantum dots, graphene oxide, graphene oxide quantum dots, and reduced graphene oxide. These materials and their various modifications and combinations with other compounds are discussed, regarding their biomedical and agro-ecological applications, i.e., as materials investigated for their antineoplastic and anti-invasive effects, for their effects against various plant pathogens, and as carriers of bioactive agents (drugs, pesticides, fertilizers) as well as materials suitable to be used in theranostics. The negative effects of graphene-based nanomaterials on living organisms, including their mode of action, are analyzed as well.

Targeted inhibition of methicillin-resistant Staphylococcus aureus biofilm formation by a graphene oxide-loaded aptamer/berberine bifunctional complex

Biofilm formation is known to promote drug resistance in methicillin-resistant Staphylococcus aureus (MRSA), which is closely related to persistent infections in hospital settings. In this study, a DNA aptamer specific to penicillin-binding protein 2a (PBP2a) with a dissociation constant (K_d) of 82.97 ± 8.86 nM was obtained after 14 cycles of systematic evolution of ligands by exponential enrichment (SELEX). Next, a bifunctional complex containing the aptamer intercalated by berberine into the double-strand region was prepared and adsorbed onto the surface of graphene oxide (GO) by π-stacking interactions. The GO-loaded aptamer/berberine bifunctional complex showed significantly higher inhibition of MRSA biofilm formation than the control. Furthermore, this study shows that the complex possesses anti-biofilm activity, which can be attributed to the ability of the aptamer to reduce cell-surface attachment by blocking the function of PBP2a and berberine to attenuate the level of the accessory gene regulator (agr) system, which plays an important role in mediating MRSA biofilm formation. Therefore, the simultaneous delivery of berberine and PBP2a-targted aptamer using GO may have potential for the treatment of chronic infections caused by MRSA biofilms. It also provides a new avenue for multitarget treatment of bacterial biofilms.

Adsorption-Based Removal of Sb (III) from Wastewater by Graphene Oxide-Modified Zirconium-Based Metal-Organic Framework Composites

The treatment of Sb (III) wastewater produced from mining activities is uniquely challenging and has therefore garnered increasing attention. Here, an amino-modified zirconium-based metal-organic framework material (UiO-66-NH2) and its composites were loaded onto graphene oxide (GO@UiO-66-NH2) via the hydrothermal method, after which these materials were used to adsorb Sb (III) in mine wastewater. The effects of adsorption time, pH, initial Sb (III) concentration, temperature, and adsorbent dosage on the removal performance of Sb (III) were then investigated. The adsorption processes of Sb (III) were examined via adsorption kinetic, isotherm, and thermodynamic analyses. XRD, SEM, and FTIR analyses demonstrated the presence of a porous structure and high levels of oxygen-containing functional groups on the UiO-66-NH2 and GO@UiO-66-NH2 surfaces. During the Sb (III) adsorption process, the adsorption rates of UiO-66-NH2 and GO@UiO-66-NH2 were very fast in the first 10 minutes, and the adsorption equilibrium was achieved in 12 h, with the adsorption efficiencies of 91.76% and 93.79%, respectively. At a pH of 7.0, 25°C, an initial Sb (III) concentration of 100 mg/L, and an adsorbent dosage of 0.04 g/L, the maximum Sb (III) adsorption capacities of UiO-66-NH2 and GO@UiO-66-NH2 reached 39.23 mg/g and 61.07 mg/g, respectively. The adsorption process was accurately described by the Langmuir model, meaning that the Sb (III) was adsorbed through single-layer uniform adsorption. Moreover, the adsorption process was highly consistent with the pseudo-second-order model, which was indicative of spontaneous and endothermic chemical adsorption. Additionally, the Sb (III) removal efficiency could be maintained approximately 70% after sorption-desorption recycling four times. Therefore, our study provides an economical and effective method for the removal of Sb (III) in wastewater treatment.

Effect of consumption of I, Se, S and nanoaquacitrates on hematological and biochemical parameters of the organism of rabbits

Using nanotechnologies to obtain compounds of mineral substances is promising because of the importance of the amount of mineral substances, but the limiting factor is particularly their bioavailability in the digestive tract. The conducted studies determined the stimulating effect of nanoaquachelates of separate biogene microelements on the course of biochemical processes of the organisms of animals, their productivity and quality of the obtained products. However, the mechanisms of impact of carboxylates of separate elements and their combinations on functioning of physiological systems of various species of animals, level of transformation of these elements into the products and their biological value remain unstudied. Therefore, the objectives of the study were changes in hematological biochemical and productive parameters of the organisms of rabbits consuming I, Se, S, the impacts of these elements on their organism from the 53 to 85th days of life. Studies were performed on young Termonde rabbits. Animals of experimental groups I, II, III, and IV were fed with feeds of the diet of the control group for 24 h with water containing solution of І, Se, S calculated respectively as 2.5, 5.0, 10.0 and 20.0 µg of І/L of water. The experiment lasted 45 days, including a 12 day preparation period and 33 day experimental. On the 53rd day of life of animals in the preparation period, and 68th and 85th days of life in the experimental periods (15th and 33rd days of watering with supplements), we collected samples of blood from the marginal ear vein of 6 animals (3 males and 3 females) of the group for hematological and biochemical studies. We determined that watering with the solution of microelements І, Se, S led to changes in the overall amount of white blood cells, making it 17.1% lower in the blood of animals of the experimental group II, 26.2% higher in group ІІІ on the 15th day, and 12.0% higher in group IV on the 31st day of the experiment compared with the control. Absolute amounts of lymphocytes, monocytes and granulocytes by the periods of the study were observed to have no significant changes throughout the study, though their parameters were within the physiological values compared with the control. The amount of red blood cells in the blood of rabbits of experimental groups І, ІІ and ІІІ was higher respectively by 8.1%, 5.7% and 12.0% at the first stage of the study and 18.1%, 13.3%, 24.5% and 24.9% higher in animals of experimental groups І, ІІ; ІІІ and ІV at the final stage of the study compared with the control group. Hemoglobin concentration in blood of rabbits of experimental groups II and III during the study was significantly higher. Hematocrit value in blood of rabbits of experimental groups I–III was significantly higher on the 33rd day of the experiment compared with the control. Consumption of solution of microelements in the amount of 10.0 µg of I/L by the animals of experimental group III led to 15.1% higher content of total protein in the blood on the 33rd day of the study compared with the control group of animals. The level of creatinine was no higher than the physiological parameters and was 9.2%, 15.0% and 15.4% higher in the blood of rabbits of experimental groups II, III, IV on the 33rd day of the experiment compared with the control group. No significant changes in the content of triacylglycerols in the blood of rabbits of the experimental groups were seen throughout the study. However, the content of cholesterol in the blood of rabbits of experimental groups III and IV was significantly higher at the first stage compared with the control group. Further, it is practical to study physiologically substantiated amounts of solution of microelements І, Se, S in the diet of mother rabbits to determine their effect on their ability to become pregnant, reproductive function, milk production and survival of offspring.

Advances in Drug Delivery Nanosystems Using Graphene-Based Materials and Carbon Nanotubes

Carbon is one of the most abundant elements on Earth. In addition to the well-known crystallographic modifications such as graphite and diamond, other allotropic carbon modifications such as graphene-based nanomaterials and carbon nanotubes have recently come to the fore. These carbon nanomaterials can be designed to help deliver or target drugs more efficiently and to innovate therapeutic approaches, especially for cancer treatment, but also for the development of new diagnostic agents for malignancies and are expected to help combine molecular imaging for diagnosis with therapies. This paper summarizes the latest designed drug delivery nanosystems based on graphene, graphene quantum dots, graphene oxide, reduced graphene oxide and carbon nanotubes, mainly for anticancer therapy.

Potential use of 3D-printed graphene oxide scaffold for construction of the cartilage layer

Background

Three-dimensional (3D) printing involves the layering of seed cells, biologically compatible scaffolds, and biological activity factors to precisely recapitulate a biological tissue. Graphene oxide (GO), a type of micro material, has been utilized as a small molecule-transport vehicle. With the proliferation of GO, the biocompatibility of chondrocytes in a microenvironment constructed by 3D printed scaffolds and GO is innovative. Accordingly, we speculate that, as a type of micro material, GO can be used with 3D scaffolds for a uniform distribution in the cartilage layer.

Results

A qualitative analysis of the chondrocyte-proliferation potential revealed that the culture of 3D printing with a 10% GO scaffold was higher than that of the other groups. Meanwhile, the progress of cell apoptosis was activated. Through scanning electron microscopy, immunofluorescence, and in vivo research, we observed that the newborn cartilage matrix extended along the border of the cartilage and scaffold and matured. After an analysis with immunohistochemical staining with aggrecan and collagen I, the cartilage following the 3D-printed scaffold was thinner than that of the 3D-printed GO scaffold. Furthermore, the collagen I of the cartilage expression in treatment with the GO scaffold was significant from week 2 to 6.

Conclusions

The findings indicate that a 3D-printed GO scaffold can potentially be utilized for the construction of a cartilage matrix. However, the optimum concentration of GO requires further research and discussion.

Graphenic Materials for Biomedical Applications

Graphene-based nanomaterials have been intensively studied for their properties, modifications, and application potential. Biomedical applications are one of the main directions of research in this field. This review summarizes the research results which were obtained in the last two years (2017-2019), especially those related to drug/gene/protein delivery systems and materials with antimicrobial properties. Due to the large number of studies in the area of carbon nanomaterials, attention here is focused only on 2D structures, i.e. graphene, graphene oxide, and reduced graphene oxide.

Potential of Nanomaterial Applications in Dietary Supplements and Foods for Special Medical Purposes

Dietary supplements and foods for special medical purposes are special medical products classified according to the legal basis. They are regulated, for example, by the European Food Safety Authority and the U.S. Food and Drug Administration, as well as by various national regulations issued most frequently by the Ministry of Health and/or the Ministry of Agriculture of particular countries around the world. They constitute a concentrated source of vitamins, minerals, polyunsaturated fatty acids and antioxidants or other compounds with a nutritional or physiological effect contained in the food/feed, alone or in combination, intended for direct consumption in small measured amounts. As nanotechnology provides "a new dimension" accompanied with new or modified properties conferred to many current materials, it is widely used for the production of a new generation of drug formulations, and it is also used in the food industry and even in various types of nutritional supplements. These nanoformulations of supplements are being prepared especially with the purpose to improve bioavailability, protect active ingredients against degradation, or reduce side effects. This contribution comprehensively summarizes the current state of the research focused on nanoformulated human and veterinary dietary supplements, nutraceuticals, and functional foods for special medical purposes, their particular applications in various food products and drinks as well as the most important related guidelines, regulations and directives.

Functional Graphene Oxide Nanocarriers for Drug Delivery

The family of graphene has attracted increasing attention on account of their large specific surface area and good mechanical properties in the biomedical field. However, some characteristics like targeted delivery property and drug delivery capacity could not satisfy the need of a drug carrier. Herein, a graphene oxide (GO) nanocarrier was designed by modification of a folic acid (FA) derivative and a β-cyclodextrin (β-CD) derivative in order to improve two properties, respectively. In the first step, reactive or crosslinkable FA and aldehydic β-CD (β-CD-CHO) were designed and synthesized for further modification. In the second step, synthesized functional molecules were coupled onto GO sheets one by one to obtain the GO nanocarrier. IR spectra and XRD results were used to identify the chemical and structural information before and after modification for the GO nanocarrier. The final GO nanocarrier exhibited a typical thin wrinkled sheet morphology of the GO sheet without any influence by two functional molecules. Finally, in vitro evaluation was used to clarify the drug loading and controlling capacity of the nanocarrier as a drug delivery system. The results revealed that the GO nanocarrier had a better CPT loading capacity and showed better controllability for CPT release.