Volume 2, Issue 4 - Special issue: Biomedical Nanotechnologies / Issue editor: Christoph Alexiou

The use of nanoparticles in tumor imaging, molecular imaging, and drug delivery has significantly expanded in the last few years. The relatively new field of “theranostics” combines their capacity for drug delivery with their potential as contrast agents. Depending on the imaging modality used, several types of nanoparticles are available, such as gold for optical imaging or superparamagnetic iron oxide for magnetic resonance imaging. This review will give a short overview of the different types of nanoparticles as well as their development and potential application in recent years. Furthermore, it describes the research on classic imaging modalities as well as on new techniques to image nanoparticles in vivo and focuses on magnetic-based imaging modalities.

Cancer is one of the biggest challenges facing the medical research in our time. The goals are to improve not only the therapeutic outcome, even in the cases of advanced and metastatic cancer, but also the methods of treatment, which often have considerable adverse effects. In addition, the current developments, such as demographic change, population growth, and increasing healthcare costs, have to be taken into consideration. In all likelihood, nanotechnology and, in particular, the use of magnetic nanoparticles consisting of the elements nickel, cobalt, and iron can make a significant contribution. The greatest potential can be ascribed to the drug delivery systems: magnetic nanoparticles are functionalized by binding them to various substances, including chemotherapeutic agents, radionuclides, nucleic acids, and antibodies. They can then be guided and accumulated using a magnetic field. Hyperthermia can be induced with an alternating magnetic field, providing another therapeutic option. Magnetic nanoparticles may be useful in overcoming cancer drug resistance. They also contribute to realizing a combination of diagnostic investigation and therapy in the field of “theranostics”. The multifaceted and promising results of research in the recent years offer the prospect of a real advance in cancer therapy in the near future.

As an interdisciplinary field, tissue engineering (TE) aims to regenerate tissues by combining the principles of cell biology, material science, and biomedical engineering. Nanotechnology creates new materials that might enable further tissue-engineering applications. In this context, the introduction of nanotechnology and nanomaterials promises a biomimetic approach by mimicking nature. This review summarizes the current scope of nanotechnology implementation possibilities in the field of tissue engineering of bone, muscle, and vascular grafts with forms on nanofibrous structures.

Collagen is increasingly attracting attention for bone tissue engineering applications. However, due to its low mechanical properties, applications including mechanical loads or requiring structural integrity are limited. To tackle this handicap, collagen can be combined with (nanoscale) silica in a variety of composite materials that are attractive for bone tissue engineering. Considering research carried out in the past 15 years, this article reviews the literature discussing the development of silica/collagen composites that have been synthesized by adding silica from different sources as inorganic bioactive material to collagen as organic matrix. Different routes for the fabrication of collagen/silica composites are presented, focusing on nanocomposites. In vitro cell bioactivity studies demonstrated the osteogenic and, in some cases, angiogenic potential of the composites. Relevant in vivo studies discussing integration of the materials in bone tissue are discussed. Due to the understanding of possible interaction between silicon species and collagen, the effect of different silica precursors on the collagen self-assembly process is also discussed. On the basis of literature results and as discussed in this review, collagen/silica nanocomposites and hybrids represent attractive biomaterials for bone regeneration applications.

Atherosclerosis results from the accumulation of the modified lipoproteins within the artery walls, which triggers complex vascular inflammatory processes. Although the pharmacologic agents for the treatment of clinical manifestations of atherosclerosis are available, their systemic delivery has serious disadvantages, such as considerable side effects or low efficacy at tolerated doses. Moreover, the treatment of atherosclerosis using the interventional techniques bears further shortcomings: the implanted stents require a lengthy antiplatelet therapy and carry the risk of in-stent restenosis. In the surgical approach to atherosclerosis, apart from the overall risk of open heart surgery, the lack of adequate venous material for bypasses constitutes a common problem. The nanotechnology has the potential to overcome the disadvantages of the current therapy of atherosclerosis, e.g., by the formation of nanosized assemblies for the earlier detection of atherosclerotic lesions and for cell-specific delivery of therapeutics. Replacing the current systemic pharmacological approach by a locally targeted treatment of plaques can substantially minimize the adverse effects, by lowering the drug cytotoxicity and reducing the required dosage. Moreover, a new generation of nanotechnological approaches to the revascularization procedures is now emerging, e.g., vascular tissue engineering utilizing the magnetic nanoparticles or the design of stents with the reduced risk of thrombosis and restenosis. This review discusses the possible applications of the nanomedical approaches in the treatment of cardiovascular diseases.

Recent nanotechnology research has been enhancing or creating new applications that have the potential to advance the diagnosis or therapy of diseases. These contributions to the field of nanomedicine have so far been focused on creating the new technologies rather than focusing on particular diseases in order to improve their outcomes. For the latter to occur, we recommend the following: (1) creation of interdisciplinary research funding that awards collaborations between biological, medical, clinical, and pharmaceutical scientists with their colleagues in engineering, physics, and chemistry, (2) increasing the training of bio- and medical students in the field of nanotechnology, and (3) focusing on specific diseases for creating nano-based solutions. In this review, we focus on ovarian cancer as an example of a disease that could benefit from advances in nanotechnology to enhance its understanding, diagnosis, and therapy. We also stress the need to train biological, medical, clinical, and pharmaceutical students in the field of nanotechnology with presenting results on such training in USA pharmacy schools.