Francisca Villanueva-Flores is studying her last year of PhD in biochemistry at Instituto de Biotecnología in the Universidad Nacional Autónoma de México. Her main research focuses in the development of medical nanodevices for neuronal tissue engineering. In her PhD, she synthetized a nanoimplant for restoring cellular function (unpublished data). Her research interests also include the understanding of cell-nanomaterial interactions to develop novel, efficient and safe therapeutic nanobiomaterials.
The development of novel materials as scaffolds for cell culture has gained attention. The current challenge is to provide a scaffold that mimics natural tissues. We synthetized at physiological temperature a pH-responsive and biocompatible nanostructured hydrogel with three different crosslinking degrees by varying the content of glutaraldehyde (GA). According with our data of scanning electron microscopy (SEM) and FTIR, we observed that the hydrogel is conformed highly ordered nanofibers of poly (vinyl alcohol co-vinyl acetate) (nsPAcVA). By atomic force microscopy (AFM), we showed that nsPAcVA has nanopores homogeneously distributed on its surface. We characterized the relative amount of remaining hydroxyl groups and of formed acetal bridges by FTIR, and by mechanical tests, we measured the Young’s modulus, strain stress, elastic deformation and tensile strength. nsPAcVA had swelling dynamics dependent on pH and crosslinking. By cyclic voltammetry, we showed that nsPAcVA has ionic conductivity properties inversely proportional to its crosslinking degree. Based on this, we evaluated its capability to controllably release a model molecule. Diffusion analysis through the Peppas equation showed that at lower crosslinking degrees (5 and 10% of GA content), diffusion from nsPAcVA was Fickian. Moreover, we demonstrated for the very first time that nsPAcVA is an efficient scaffold for growth of mammalian cells (embryonic mouse hypothalamic mHypoE-N1 and human lung carcinoma A-549 cells). mHypoE- grown on nsPAcVA had lower proliferation than the control, but after 108 h of adaptation, cells proliferated at comparable growth levels than the control. No significant difference in A-549 cell growth over nsPAcVA and the control was observed. We present a very easy synthesizable, cheap, biocompatible and nanostructured scaffold for controlled drug release with promising physicochemical characteristics to be applied as a tissue engineering material that integrates abiotic and biotic components towards a new generation of smart implants which ultimately could mimic natural tissues.
Steven Mufamadi is the founder of Nabio Consulting (Pty) Ltd, a start-up company on nanotechnology and biotechnology that is based in South Africa (SA). His expertise is on bio-nanotechnology and nanomedicine formulations for pharmaceutical application. Mufamadi he is also co-founder of the nanotechnology symposia series on HIV/AIDS, TB, malaria, cancer, energy and water in partnership with SA government, an initiative that is aiming on facilitation of nanotechnology development, innovation, commercialization and public engagement in SA through dialogues between government/policy makers, researchers, industry, entrepreneurs and investors.
Cancer is a global threat; about 8.2 million people die as a result of cancer each year. In South Africa, cancer has increased from 5.6 to 9% between 2006 and 2015. Nanotechnology is a most promising field for generating new applications in medicine. The anti-proliferative and apoptosis inducing properties of silver nanoparticles (Ag NPs) makes them ideal candidates for anticancer therapy. The purpose of this study is to illustrate the biological synthesis of Ag NPs using plant extracts for Nanomedicine; also, to showcase the mechanism of action of the Ag NPs on cancer cell lines and the potential impact in oncology. Green synthesis of Ag NPs is a simple synthetic technique which could be achieved by blending of silver ions together with plant extracts, which can act as reducing and capping agents, to form Ag NPs with different sizes and shapes. This approach offers simplicity, rapid synthesis, environment friendly, inexpensive biological procedure for nanoparticle fabrication with low systemic toxicity to human. Additionally, green synthesis approach using plant extracts are easy to scale up for larger-scale production of nanoparticles. The use of Ag NPs as a new generation of anticancer therapy showed improved in vitro anti-cancer efficacy against different cancer cell lines at low concentration. The main mechanism of action of Ag NPs on cancer cell death involves the uptake of Ag NPs inside the cell via endocytosis or diffusion, which causes mitochondrial dysfunction and formation of reactive oxygen species (ROS), resulting in damage to cellular components such as proteins, DNA and cell membrane (Figure 1). Many studies showed that cell uptake and anticancer activity to be influenced by nanoparticle’s size (1-100nm). The toxicity of green synthesized Ag NPs on normal cells highly depends on the plant extract used for the stabilization and reduction of metal ion. Conclusion & Significance:Green silver nanotechnology using plant extracts promising to offer anticancer therapy at atomic scale and molecular level. However, in-depth study on Ag NPs properties in mammalian immune system and in vivo toxicity study is recommended in order to confirm safety and clinical significance.