Applications of Nanotechnology in Drug Delivery Systems

Every so often, a new term comes along that represents an emerging scientific trend. Biotechnology, genetic engineering, tissue engineering, gene therapy, combinatorial chemistry, high throughput screening, and stem cells are some examples of past terms. Recently, nanotechnology has become a popular term representing the main efforts of the current science and technology. Nanotechnology, which is still not a mature technology and thus, more appropriately called nanoscience, usually refers to research at the scale of 100 nm or less. Nanotechnology is unique in that it represents not just one specific area, but a vast variety of disciplines ranging from basic material science to personal care applications. Thus this technology is very advanced and various researches are a heading in this field very quickly One of the important areas of nanotechnology is “nanomedicine,” which, refers to highly specific medical intervention at the molecular scale for diagnosis, prevention and treatment of diseases The nanoparticles are available in various shapes and sizes and these are  become very important elements in novel drug delivery systems called nanomedicine. These nanoparticles are developed in appropriate sizes and used such that they target at the targeted places in the body. This development of nanoparticles had  brought a revolutionary change in the field of  drug delivery systems.. In drug delivery, nanotechnology is just beginning to make an impact. Many of the current “nano” drug delivery systems, however, are remnants of conventional drug delivery systems that happen to be in the nanometer range, such as liposomes, polymeric micelles, nanoparticles, dendrimers, and nanocrystals. Liposomes and polymer micelles were first prepared in 1960’s, and nanoparticles and dendrimers in 1970’s. Colloidal gold particles in nanometer sizes were first prepared by Michael Faraday more than 150 years ago, but were never referred to or associated with nanoparticles or nanotechnology until recently. About three decades ago, colloidal gold particles were conjugated with antibody for target specific staining, known as immunogold staining. Such an application may be considered as a precursor of recent explosive applications of gold particles in nanotechnology. The importance of nanotechnology in drug delivery is in the concept and ability to manipulate molecules and supramolecular structures for producing devices with programmed functions. Conventional liposomes, polymeric micelles, and nanoparticles are now called “nanovehicles,”. Those conventional drug delivery systems would have evolved to the present state regardless of the current nanotechnology revolution. Cancer is one of the most challenging diseases today, and brain cancer is one of the most difficult malignancies to detect and treat mainly because of the difficulty in getting imaging and therapeutic agents across the blood-brain barrier and into the brain. Many investigators have found that nanoparticles hold promise for ferrying such agents into the brain . Apolipoprotein E was suggested to mediate drug transport across the blood-brain barrier . Loperamide, which does not cross the blood-brain barrier but exerts antinociceptive effects after direct injection into the brain, was loaded into human serum albumin nanoparticles and linked to apolipoprotein E. Robust angiogenesis underlies aggressive growth of tumors. Therefore, one of the mechanisms to inhibit angiogenesis is to starve tumor cells. Angiogenesis is regulated through a complex set of mediators and recent evidence shows that integrin αvβ3 and vascular endothelial growth factors (VEGFs) play important regulator roles. The cell adhesion molecules are glycoproteins found on the cell surface that act as receptors for cell-to-cell and cell-to-extracellular matrix adhesion . Recent advancements of the understanding of the cell adhesion molecules has impacted the design and development of drugs (i.e. peptide, proteins) for the potential treatment of cancer, heart and autoimmune diseases. These molecules have important roles in diseases such as cancer, thrombosis and autoimmune diseases such as type-1 diabetes. There also is an exciting possibility to overcome problems of drug resistance in target cells and to facilitating movement of drugs across barriers such as those in the brain. The challenge, however, remains the precise characterization of molecular targets and to ensure that these molecules are expressed only in the targeted organs to prevent effects on healthy tissues. Secondly, it is important to understand the fate of the drugs once delivered to the nucleus and other sensitive cells organelles. Furthermore, because nanosystems increase efficiency of drug delivery, the doses may need recalibration. Nevertheless, the future remains exciting and wide open. Keywords : Nanotechnology, nanomedicine, nanoparticles, liposomes, polymeric micelles, nanoparticles, dendrimers, and nanocrystals. Liposomes and polymer micelles, DOI : 10.7176/APTA/80-02 Publication date :October 31 st 2019