9. Nanomedicine: Diagnosis, Treatment, and Potential Prospects

Treatment of diseases using conventional drugs is often limited by their low bioavailability, short circulation half-lives, poor solubility, and nonspecificity which results in high-dosage requirements. The high dosage of drug molecules results in higher toxicity, increasing the side effects of the conventional drugs used for treatment of diseases. Nanomedicine is the use of nanotechnology for healthcare with clinical applications ranging from disease diagnosis to formulation of carriers for drug and gene delivery applications. Use of nanotechnology-based delivery vehicles, such as nanoparticles, nanocapsules, micelles, or dendrimers, has emerged as a promising strategy to deliver conventional drugs, recombinant proteins, vaccines, and, more recently, genetic material by addressing the problems related to poor solubility, high toxicity, nonspecific delivery, in vivo degradation, and short circulation half-lives of the conventional drugs, which often limits optimal dosage at the target site. The rapidly growing nanomedicine industry not only caters to the treatment of various diseases including cancer, pain, asthma, multiple sclerosis, and kidney diseases but also helps in differentiating normal and diseased cells. Metallic, polymeric, semiconductor, and magnetic nanoparticles have been employed in engineering nanostructures that are increasingly being employed for disease diagnosis. While the unique optical, magnetic, and size-dependent properties of nanoparticles make them suitable candidates for disease diagnosis, their ability to undergo surface modification with polymers, antibodies, or aptamers helps in increasing their circulation time and reduces their potential toxicity. Conjugation of these nanoparticles with aptamers has been utilized for development of sensors with fluorescence, optical, and electrochemical detection signals which are sensitive, highly specific, reusable, and label-free. Nanostructures have improved medical diagnosis by providing inexpensive, reproducible, sensitive, and highly specific methods for disease diagnosis either in terms of sensors or as imaging agents. Nanomedicine not only includes the fields of therapeutics and diagnostics but also involves development of implantable materials and devices. Despite the innumerable advantages of nanostructures in the field of nanomedicine, only a handful of products have been able to reach the market due to several disadvantages that these magic bullets are associated with including toxicity of the said materials. However, maintenance of a balance between the advantages and disadvantages would definitely open up avenues for personalized medicine through therapeutics, diagnostics, and theranostics. The present chapter discusses the current state-of-the-art materials used in nanomedicine for disease diagnosis or treatment, problems associated with them, and future prospects of nanomedicine toward personalized medicine.