A New Approach to Obtaining Nano-Sized Graphene Oxide for Biomedical Applications

l-Asparaginase Immobilized on Nanographene Oxide as an Efficient Nanobiocatalytic Tool for Asparagine Depletion in Leukemia Cells

l-Asparaginase (l-ASNase) catalyzes the hydrolysis of l-asparagine, leading to its depletion and subsequent effects on the cellular proliferation and survival. In contrast to normal cells, malignant cells that lack asparagine synthase are extremely susceptible to asparagine deficiency. l-ASNase has been successfully employed in treating pediatric leukemias and non-Hodgkin lymphomas; however, its usage in adult patients and other types of cancer is limited due to significant side effects and drug resistance. Recent research has explored alternative formulations and delivery methods to enhance its efficacy and minimize adverse effects. One promising approach involves the immobilization of l-ASNase onto nanostructured materials, offering improved enzymatic activity and biocompatibility of the support. We harnessed an E. coli l-ASNase type II preparation to develop a novel strategy of enzyme immobilization on graphene oxide (GO)-based support. We compared GO and nanographene oxide (nGO) in terms of their biocompatibility and influence on enzyme parameters. The obtained l-ASNase on the nGO nanobiocatalyst maintains enzymatic activity and increases its stability, selectively acting on K562 leukemia cells without cytotoxic influence on normal endothelial cells. In the case of treated K562 cells, we confirmed enlargement in the cell and nucleus size, disturbance in the cell cycle (interphase and metaphase), and increased apoptosis rate. The potential therapeutic possibilities of immobilized l-ASNase on leukemia cell damage are also discussed, highlighting the importance of further research in this area for advancing cancer therapy.

ZnO-Graphene Oxide Nanocomposite for Paclitaxel Delivery and Enhanced Toxicity in Breast Cancer Cells

A ZnO-Graphene oxide nanocomposite (Z-G) was prepared in order to exploit the biomedical features of each component in a single anticancer material. This was achieved by means of an environmentally friendly synthesis, taking place at a low temperature and without the involvement of toxic reagents. The product was physicochemically characterized. The ZnO-to-GO ratio was determined through thermogravimetric analysis, while scanning electron microscopy and transmission electron microscopy were used to provide insight into the morphology of the nanocomposite. Using energy-dispersive X-ray spectroscopy, it was possible to confirm that the graphene flakes were homogeneously coated with ZnO. The crystallite size of the ZnO nanoparticles in the new composite was determined using X-ray powder diffraction. The capacity of Z-G to enhance the toxicity of the anticancer drug Paclitaxel towards breast cancer cells was assessed via a cell viability study, showing the remarkable anticancer activity of the obtained system. Such results support the potential use of Z-G as an anticancer agent in combination with a common chemotherapeutic like Paclitaxel, leading to new chemotherapeutic formulations.

Rheological Properties of Different Graphene Nanomaterials in Biological Media

Carbon nanomaterials have received increased attention in the last few years due to their potential applications in several areas. In medicine, for example, these nanomaterials could be used as contrast agents, drug transporters, and tissue regenerators or in gene therapy. This makes it necessary to know the behavior of carbon nanomaterials in biological media to assure good fluidity and the absence of deleterious effects on human health. In this work, the rheological characterization of different graphene nanomaterials in fetal bovine serum and other fluids, such as bovine serum albumin and water, is studied using rotational and microfluidic chip rheometry. Graphene oxide, graphene nanoplatelets, and expanded graphene oxide at concentrations between 1 and 3 mg/mL and temperatures in the 25–40 °C range were used. The suspensions were also characterized by transmission and scanning electron microscopy and atomic force microscopy, and the results show a high tendency to aggregation and reveals that there is a protein–nanomaterial interaction. Although rotational rheometry is customarily used, it cannot provide reliable measurements in low viscosity samples, showing an apparent shear thickening, whereas capillary viscometers need transparent samples; therefore, microfluidic technology appears to be a suitable method to measure low viscosity, non-transparent Newtonian fluids, as it is able to determine small variations in viscosity. No significant changes in viscosity are found within the solid concentration range studied but it decreases between 1.1 and 0.6 mPa·s when the temperature raises from 25 to 40 °C.