Bi-functional nanostructured semiconductor photocatalysts for renewable energy Production and environmental Remediation

Abstract:

Photocatalytic wastewater treatment and concurrent energy production is a promising strategy to address the renewable energy supply and environmental degradation issues (1). Many efforts have been devoted in recent years for achieving enhanced photocatalytic activity as well as optimizing reaction conditions and materials design towards sustainability and economic growth.  In this presentation, various strategies are introduced to develop efficient dual-functional semiconductor photocatalysts for environmental remediation and simultaneous renewable energy production (2). Some of the major concurrent photocatalytic reactions that will be addressed are including i) photocatalytic H₂ generation combined with oxidation of organic pollutants, ii) photocatalytic mineralization of organic pollutants and reduction of produced CO₂ to useful chemicals,  iii) photocatalytic removal of  mixture of organic pollutants and heavy metals, iv) H⁺ and CO₂ reduction and v) simultaneous H₂ and H₂O₂ productions. To enhance the overall reaction, it is necessary to understand elementary processes of photocatalysis such as photophysics and chemistry at the surface/interface of nanostructured phototcatalyst. During photocatalysis for renewable energy production from wastewater treatment, the organic pollutant can either play as a hole scavenger or as an electron donor to increase the rate of H₂ production. Moreover, simultaneous adsorption and photodegradation of drugs such as tetracycline on the studied photocatalysts will be introduced.  Finally, charge transfer mechanism during the reaction on nanostructured semiconductor photocatalysts will be proposed.

 

 

Nanotechnology in Renewable Energy: Borophene vs. Graphene-based Nanomaterials 

Abstract:

The energy consumption has been substantially increased in recent decades due to the world population growth, industrialization, and improving living standards in the developing countries. The development and use of renewable energy sources (solar and wind energies) has attracted much recent attention because of the considerable price decline of them and also the side effects of using fossil fuels on the environment such as greenhouse gas emissions, global warming, and rising global fuels prices. Since the nanoscale materials have significant properties, nanotechnology and nanoscience as the special fields exhibit the unique potential applications to improve environment and to expand the use of renewable resources. One of the most nanotechnology and nanoscience applications is synthesis of nanomaterials for the renewable energy storage devices such as fuel cells, batteries and supercapacitors. Graphene/graphene-based nanocomposites are one of the best known and widely used nanomaterials in the field of energy. Graphene is a monolayer of carbon atoms with sp²-hybridized bond that are joined together in a hexagonal lattice to form a two-dimensional structure. Recently, lots of research has been done on graphene-based nanomaterials for battery technology, fuel cells, solar cells, and energy storage devices. A new substance has come from synthesis in 2015 called “borophene”, which contains boron atoms instead of carbon atoms in graphene. Borophene is stronger than graphene with very good conductivity of both electricity and heat. What do you think about the future of borophene-based nanomaterials in renewable energy systems?

Design of a Novel Multifunctional prosthetic Mesh with an Absorbable Nanofiber Layer as a Potential Implant for repairing of abdominal wall hernias and defects

Abstract:

This talk is mainly focused on scientific strategies to design, develop and evaluate a new multifunctional prosthetic mesh for treatment of abdominal wall defects, especially hernia without complications. Abdominal wall defects caused by ventral hernia, trauma, infection, and tumour resection are frequent problems in abdominal surgery. Currently, hernioplasty, a type of hernia repair surgery where a mesh patch is sewn over the weakened region of a tissue, represents the standard technique for repairing inguinal hernia worldwide. An optimal mesh should play another role, which is important to be used in abdominal hernia regeneration. It assists the healing process hernia defect by supportive ingrowth of the body’s connective tissue by the induction of strong collagen tissue around the mesh fibers. However, the use of these materials has its complications. Hernia operations are often expected to face the risk of mesh adhesion to surrounding tissues, especially in the abdominal zone. Besides, prostheses are permanent foreign materials in the body that may cause chronic inflammation, infection, and other complications. After general abdominal surgery, abdominal peritoneal adhesions are reported in 67–93% of patients who receive an artificial synthetic mesh. These adhesions cause severe morbidity due to complications, such as intestinal obstruction, enterocutaneous fistulas, and pain. Moreover, extensive abdominal wall defects with voluminous hernias still represent a great challenge due to the large size ring with marginal distortion. Furthermore, large defect with tension on the closure of the wound can affect surgical outcome Therefore, surgeons and researchers still working on developing new techniques to improve the surgical outcomes. Double-layered composite meshes developed in recent years, could support the healing of the wound on one side, the other surface contacts with the viscera has to have non-sticking property. The non-sticky layer of the composite meshes may exhibit a temporary or permanent non-sticky property, where the temporary layer is needed until the wound healing process is completed. Considering the positive characteristics of nanofibers, it has attracted more interest than other ways to treat the inflammatory and infectious diseases as well as anti-adhesion barriers. These topics will be covered here in this talk and some research experiences related to this topic will be presented as well.

Metal-organic framework-based nanostructures for renewable energies and environmental applications

Abstract:

Metal-organic frameworks (MOFs), also known as porous coordination polymers (PCPs), constructed by inorganic nodes (metal ions/clusters) with organic linkers, have emerged as an exciting class of crystalline materials with flexible tunability in porous structure and composition, rich topology, enhanced surface area, and broad visible-light absorption. These characteristics enable MOFs to show potential applications in the various fields of heterogeneous catalysis, gas storage, separation, chemical sensors, water oxidation, and supercapacitors. To satisfy the practical applications of MOFs, controllable integration of MOFs and functional materials (e.g., metal nanoparticles, graphitic carbon nitride, covalent organic frameworks, magnetic nanoparticles, graphene oxide, and layered double hydroxides) is leading to the creation of many new multifunctional materials, which can enhance the characteristics of MOFs through activity improvement and framework stabilization. In this lecture, we will discuss recent advances in MOF-based nanostructures targeted for renewable ‎energies and environmental applications.‎

The role of Nanotechnology in Cancer diagnosis, treatment, and prediction

Abstract:

Tumors are the main causes of morbidity and mortality worldwide. Despite the efforts of the clinical and research communities, little has been achieved in the past decades in terms of improving the treatment of aggressive tumors. Understanding the underlying mechanism of tumor growth and evaluating the effects of different therapies are valuable steps in predicting the survival time and improving the patients’ quality of life. Several studies have been devoted to tumor growth modeling at different levels to improve the clinical outcome by predicting the results of specific treatments. Recent studies have proposed patient-specific models using clinical data usually obtained from clinical images and evaluating the effects of various therapies.

In cancer, one of the main barriers to effective chemotherapy is inefficient drug delivery because of drug distributions in both tumor and other normal tissues. Thus, new approach is applying targeted drug delivery by using nano carriers and external magnetic and acoustic fields.

Mathematical and computational modeling allows for controlled study of these processes which is not possible or not economical, through empirical methods. These approaches led to personalized medicine to efficient cancer treatment by controlling drug dosage and reaching to target tissue.

Nanomaterials based Biosensors: Revolution of Nanotechnology in Biosensing and Medical Diagnoses

Abstract:

Early detection of non-communicable diseases and screening for illness symptoms in communities are important parts of a medical services in any country. If such programs want to be performed with the usual laboratory tests and diagnostic methods using different scopes, it is time consuming and imposes a large financial burden on the medical system and the country. Portable medical sensors and devices were able to meet this need to a large extent. However, detection of low concentration biomarkers in biological fluids non-invasively were challengeable and required the construction of more sensitive devices with acceptable accuracy and precision. Besides, a need to miniaturize sensors for use in vivo online monitoring during many biological researches or for medical gadgets or even assembling on mobile-phones was raised. With the advent of nanotechnology and the introduction of various nanomaterials, the world of biosensors experienced huge changes. Various nanomaterials were widely applied for the design of biosensors to improve immobilization of bioreceptors, catalyze response processes, increase response time, extend sensor lifetime, increase signal to noise ratio, or even act as transducers. Integration of nanotechnology and biosensors technology led to introduce new devices, gadgets and rapid tests in human life which increased his life quality to a high extent. Here, some features and recent advances are reviewed.

Microfluidic Devices for 2D and 3D Cell Migration in Controllable Microenvironments

Abstract:

Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduce a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells (NSCs) were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor (VEGF) concentration gradients, adult human dermal microvascular endothelial cells (HDMVECs) were also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient was required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.