Article updated on 16 January 2020.
Artificial nanostructures, such as nanoparticles and nanodevices, being of the same size as biological entities, can readily interact with biomolecules on both the cell surface and within the cell.
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Nanomedical developments range from nanoparticles for molecular diagnostics, imaging, and therapy to integrated medical nanosystems, which may perform complex repair actions at the cellular level inside the body in the future.
Nano Medicine is a fast-emerging field of research which is closely associated with three interrelated terms:
• Nano diagnostics
• Targeted drug delivery system
• Regenerative medicine Nano diagnostics
The goal of nano diagnostics is to identify disease at the earliest stage possible, ideally at the level of a single cell. Nanotechnology can offer diagnostic tools of better sensitivity, specificity, and reliability. Advancement in microscopic and spectroscopic techniques towards ultra-high spatial resolution, molecular resolution developed a highly sensitive and reliable detection process. The main concept of nano diagnostic is “find, fight and follow”, i.e., theragnostic.
Nano diagnostics plays a vital role in managing cancer and infectious diseases. One of the advanced techniques of detecting cancer involves combining QDs coated with paramagnetic liquid and silica nanoparticle to generate an MRI probe. This probe is being used to detect molecules involved in cancer. In the case of detecting infectious diseases, one aspect is to identify the specific pathogens in patients.
Nano diagnostics provides a fast, inexpensive, and reproducible method to detect pathogens/viruses in patients. On the other hand, conventional methods of detection of pathogens are time-consuming, with less sensitivity. In the recent past, several nanotechnology-based approaches have been developed to detect α-synuclein, dopamine (Parkinson's disease) and mitochondrial dysfunction. It also represents a promising approach for Alzheimer's disease diagnosis and treatment.
Targeted Drug Delivery Systems
The long-term objective of drug delivery systems is the ability to target selected cells and/or receptors within the body. Nanotechnology is critical in reaching these goals. Nanoparticles are useful as drug carriers for the effective transport of poorly soluble therapeutics. When a drug is suitably encapsulated, in nanoparticulate form, it can be delivered to the appropriate site, released in a controlled way and protected from undergoing premature degradation.
This results in higher efficacy and dramatically minimizes undesirable side effects. Such nanoparticulate delivery systems can be used to more effectively treat cancer and a wide range of other diseases, which calls for drugs of high potency.
Cancer immunotherapy is a potential treatment option under clinical settings. But the major challenges of immunotherapy include limited patient response, limited tumor specificity, immune-related unfavorable events, an immunosuppressive tumor microenvironment. Therefore, a nanoparticle-based drug delivery system has been used to not only increase the efficacy of immunotherapeutic agents but also significantly reduce the toxicity. Recently, advanced nanoparticle-based drug delivery systems were effectively utilized in cancer immunotherapy to reduce the toxic side effects and immune-related adverse events.
A future vision is to develop nanoparticles that carry therapeutic payloads or genetic content into diseased cells, minimizing side effects, as the nanoparticles will only become active upon reaching their ultimate destination. They may even check for overdosage before becoming active, thus preventing drug-related poisoning.
The goal of regenerative medicine is to achieve functional rehabilitation of tissue or cells injured through a wound, disease, or aging. Current research highlights that nanotechnology provides advanced biomaterials with specified morphologies which can create a nanoscale extracellular environment capable of promoting the adhesion and proliferation of stem cells and accelerating stem cell differentiation in a controlled manner in tissue engineering.
The focus of regenerative medicine is to work with the body’s own repair mechanisms, preventing and treating disabling chronic diseases such as diabetes, osteoarthritis, and degenerative disorders of the cardiovascular and central nervous system and to help victims of disabling injuries.
Rather than targeting the symptoms or attempting to delay the progress of these diseases, future therapies will be designed to rectify chronic conditions using the body’s own healing mechanisms. To name some examples: facilitating the regeneration of healthy cartilage in an osteoarthritic joint, re-establishing a physiological release profile in diabetic pancreatic islets, or promoting self-repair mechanisms in areas of the central nervous system and of the heart.
Nanotechnology helps in delivering these growth factors effectively at the target site and also extends local availability considerably, thereby reducing the healing time. Most of the growth factors used in skin regeneration are administered topically using gelatin, collagen, and hyaluronic acid-modified systems.
Nanotechnology can play a pivotal role in the development of cost-effective therapies for in-situ tissue regeneration. This involves not only a deeper understanding of the basic biology of tissue regeneration but also identifying effective ways to initiate and control the regenerative process. This ‘nanobiomimetic’ strategy depends on three basic elements:
• Intelligent biomaterials
• Bioactive signaling molecules
By ‘tailoring’ resorbable polymers at the molecular level for specific cellular responses, nanotechnology can assist in the development of biomimetic, intelligent biomaterials. These biomaterials are designed to react positively to changes in the immediate environment, stimulating specific regenerative events at the molecular level, directing cell proliferation, cell differentiation, and extracellular matrix production and organization.
The sequential signaling of bioactive molecules, which triggers regenerative events at the cellular level, is necessary for the fabrication and repair of tissues. Nano-assisted technologies should enable the sequential delivery of proteins, peptides, and genes to mimic nature’s signaling cascade. As a result, bioactive materials are produced, which release signaling molecules at controlled rates that in turn activate the cells in contact with the stimuli.
Nano-assisted technologies will aid in achieving two main objectives – to identify signaling systems, in order to leverage the self-healing potential of endogenous adult stem cells; and to develop efficient targeting systems for stem cell therapies.
Of huge impact would also be the ability to implant cell-free, intelligent bioactive materials that would effectively provide signaling to stimulate the self-healing potential of the patient’s own stem cells. Nanotechnology application for hepatocyte regeneration is relatively new but is a rapidly developing field with a promising future.
Nanoparticles and nanostructured scaffolds provide an exact mimic of hepatic ECM facilitating the differentiation of progenitor cells into hepatocytes. A recent achievement in the hepatic regeneration is the development of silymarin nanoparticles using nanoprecipitation.
Source: European Commission