ABSTRACT
Various types of hybrid magnetic nanoparticles (MNPs) under the dispersion aspect have been applied successfully for the develop-ment of novel diagnostic techniques and therapeutic approaches for many diseases, including cancers. In this direction, the newer diagnostics and therapeutic agents based on MNPs are continuously developed. A unique feature of these MNPs is that these can be en-capsulated in other materials such as functional polymers as well as a silica matrix. Furthermore, intense efforts are being made to
employ the MNPs to deliver these to the targeted organ or effective site and test their performance. Thus hybrid MNPs and their colloi-dal forms with desirable functional and reactive characteristics are very promising because of their several intrinsic properties such as their high specific surface area, shape, chemical composition, size and surface functionality control, surface charge nature and density, degradation, internal morphology, and responsiveness to stimuli of pH, light, and temperature. Due to the dual role of the MNPs in di-agnostics and therapy, now a new subfield known as theranostics has emerged and generated high interest in the treatment of dis-eases and is primarily applied for cancer. One principal advantage is evident that due to dual functions of MNPs: these can enable us to save critical time for treatment of fatal diseases like cancer where the lapse between diagnosis and therapy is very important. In addition, the controlled release of therapeutic agents for cancer treatment to the tumor site is also a challenging field at present. Because of novel development in the MNPs, these particles can be tailored, as required, to serve as therapeutics drug delivery vehicles. In view of the above-mentioned importance of MNPs and their role in diagnostics, therapy, and drug delivery, the current chapter pro-vides an overview on some of the latest developments about MNPs such as their role as biomedical materials, encapsulation and release from silica matrix, in vitro and in vivo diagnostics of cancer, pH-and temperature-responsive drug release, magnetic resonance imaging (MRI) and tumor diagnostics, and theranostics. In addition, a short description of nanomaterials toxicities is also given at the end. 9.1 IntroductionBiomedical nanotechnology has given a variety of opportunities to fight against many diseases. Drug and gene delivery, protein and peptide delivery, and recent advancements of theranostics are the important subfields along with other applications. Diseases, which are in dire need of complete solutions to save humanity, include diabetes mellitus, cancer, and neurodegenerative and cardiovascular diseases. Every year millions of people lose their struggle for life against these well-known illnesses. Cancer is important and has been well investigated for a cure but still there is no valuable success.
Along with other branches like nanonephrology, advancements in proteomics, and genomics, nanotechnology has also emerged as one of the most fruitful applications in oncology and can be understood as a definite medical boon for diagnosis, treatment, and prevention of cancer disease. In the last decade, the application of nanotechnologies for drug delivery in cancer has been extensively explored with hope to improve the efficacy and to reduce side effects of chemotherapy (Douzeich-Eyrolles et al., 2007). It might be applied in cancer through molecular tumor imaging, early detection (like high-throughput nanosensor devices for detecting the biomarkers of cancer), molecular diagnosis, targeted therapy, and cancer bioinformatics. Considering the preference is intratumoral administration, the various methods of direct introduction of anticancer drugs should kept in mind, including injection of drugs directly into the tumor, tumor necrosis therapy, injection into the arterial blood supply of cancerous tissues, local injection into tumor for radiopotentiation, localized delivery of anticancer drugs by electroporation (electrochemotherapy), and local delivery by anticancer drug implants. Further specification may include heat-activated targeted drug delivery, tissue-selective drug delivery, use of vascular-targeting agents, use of a carrier, or selective permeation of the anticancer agent into the tumor. The choice of the method depends upon the stage and location of the tumor, drug specifications, and the importance of treatment. In the present chapter, we have tried to shed some light on the cancer nomenclature, diagnosis, treatment, classification of the nanomaterials used at present for the treatment, their use in controlled release for both diagnosis and treatment purposes, and, at the end, toxicities of nanomaterials in short. From the perspective of diagnosis and therapy of cancer, there is a great focus on the nanomaterials at the moment. One main characteristic, which distinguishes nanomaterials from their bulk counterparts, is the scale of various materials. Figure 9.1 presents an elegant view to compare the size range of various materials. Furthermore, various nanomaterials have been developed and include photonic particles (such as quantum dots [QDs]) as optical probes to monitor DNAs and the interactions of proteins; metallic nanoparticles as plasmonic nanoprobes; magnetic nanoparticles (MNPs) as unique probes to detect proteins, bacteria, cells, and
