Nanotechnology in healthcare (Part 2: Nanomedicine therapy)
In terms of therapy, the most significant impact of nanomedicine is expected to be realized in drug delivery and regenerative medicine. Nanoparticles enable physicians to target drugs at the source of the disease, which increases efficiency and minimizes side effects. They also offer new possibilities for the controlled release of therapeutic substances. Nanoparticles are also used to stimulate the body's innate repair mechanisms. A major focus of this research is artificial activation and control of adult stem cells.
The diagram below indicate what has already been achieved and what are the future prospects for nanomedicine:
Source: Philips Medical Systems (7th FWP refers to the European Union's Seventh Framework Program) (click on image to enlarge)
Let's take a look at examples of nanomedicine approaches in select areas:
Cancer nanomedicine
Nanotechnology in cancer treatments is already a reality providing a wide range of new tools and possibilities, from earlier diagnostics and improved imaging to better, more efficient, and more targeted therapies. We mentioned cancer diagnosis and imaging in the above sections.
In therapy, nanotechnology is at the forefront of both targeted drug delivery and intrinsic therapies. For instance, nanoparticles can be used as tumor-destroying hyperthermia agents that are injected into the tumor and then be activated to produce heat and destroy cancer cells locally either by magnetic fields, X-Rays or light.
Sneaking existing chemotherapy drugs or genes into tumor cells via nanomaterials allows much more localized delivery both reducing significantly the quantity of drugs absorbed by the patient for equal impact and the side effects on healthy tissues in the body.
Coupling both modes of action has also been achieved with gold nanorods carrying chemotherapy drugs and locally excited in the tumor by infrared light. The induced heat both releases the encapsulated drug and helps destroying the cancer cells, resulting in a combined effect of enhanced delivery and intrinsic therapy.
Smart cancer theranostics – a combination of the words therapeutics and diagnostics – describes a treatment platform that combines a diagnostic test with targeted therapy based on the test results, i.e. a step towards personalized medicine.
The drug release mechanism via functional outcome of the pH response illustrated in the schematic diagram. (Image: Smart Materials and Biodevice group, Linköping University)
Nanomedicine targeting atherosclerosis
Although current treatments have reduced the number of deaths from atherosclerosis-related disease, atherosclerosis remains a dangerous health problem: Atherosclerotic cardiovascular disease causes 56 million deaths annually worldwide.
In one recent study, targeted biodegradable nano 'drones' delivered a special type of drug that promotes healing successfully restructured atherosclerotic plaques in mice to make them more stable. This remodeling of the plaque environment would be predicted in humans to block plaque rupture and thrombosis and thereby prevent heart attacks and strokes.
In another study, researchers developed a new therapy to treat atherosclerosis and prevent heart failure with a new biomedical nanopolymer that reduces arterial plaque and inflammation in the cardiovascular system.
Nanomedicine to combat diabetes
Painful insulin injections could become a thing of the past for diabetes sufferers when smart insulin patches start replacing injections for diabetes.
Other ongoing research projects study the delivery of insulin in the form of nanoparticles into the nose, or into lungs as a spray, or through the gastrointestinal tract as a pill. In each case, non-invasive and painless application routes have been opened by the use of nanoparticles. Furthermore, tests are currently being conducted on nanomaterials engineered with a glucose responsive coating; these can act as an insulin depot once injected under the skin.
Scientists even are working on a Type 1 diabetes vaccine by using liposomes that imitate cells in the process of natural death.
Most ophthalmic diseases are usually treated with topically administered drug formulations (e.g. eye drops). Their main disadvantage is the short time of contact with the eye, which leads to a low degree of absorption of the active substance (less than 5% of the drug administered).
Nano- and microcarriers of drug substances can solve the problems with the drug delivery in the ocular tissues and nanoparticle drug delivery systems show great promise for related applications.
Tissue engineering is a difficult task where living cells must be organized into tissues with structural and physiological features resembling actual structures in the body.
Tissue engineering involves seeding of cells on bio-compatible scaffolds – that were fabricated through techniques like electrospinning and self-assembly – providing adhesive surfaces. Researchers though face a range of problems in generating tissue which can be circumvented by employing nanotechnology. It provides substrates for cell adhesion and proliferation and agents for cell growth and can be used to create nanostructures and nanoparticles to aid the engineering of different types of tissue.
We have posted a detailed discussion of nanomedicine research efforts that deal developing HIV AIDS treatments, i.e. diagnosing and fighting the Human immunodeficiency virus (HIV) that causes AIDS (Acquired Immune Deficiency Syndrome). Nanotechnology offers a unique opportunity to combine and improve different pharmacological profiles of antiretroviral drugs, with more convenient drug administration and potentially better patient adherence to HIV therapy.
Nanotechnology solutions to combat superbugs and antimicrobial resistance
Since their introduction about 70 yers ago, antibiotics have dramatically reduced deaths from infectious diseases. However, through overuse and misuse, many microorganisms have developed antimicrobial resistance (AMR). Antibiotic-resistance strains of tuberculosis (TB) are emerging and Methicillin-rsistant Staphylococcus aureus (MRSA) infections are a growing problem in hospitals. Today we are facing a global crisis in antibiotics caused by rapidly evolving resistance among microbes responsible for common infections that threaten to turn them into untreatable diseases. Every antibiotic ever developed was at risk of becoming useless.
The emergence of superbugs has made it imperative to search for novel methods, which can combat the microbial resistance. For this reason, the application of nanotechnology in pharmaceuticals and microbiology is gaining importance to prevent the catastrophic consequences of antibiotic resistance.
Nanotechnology based approaches to combat superbugs are advantageous to improve various preventive measures such as coatings and filtration. Similarly, diagnosis using efficient nanosensors or probes can speed up the treatment process at an early stage of disease. Nano-based drug carriers for existing antibiotics enhance their bioavailability and make them more targets specific. Also the combination of nanoparticles along with antibiotics makes them more lethal for micro-organisms.
Probable mechanisms of nanomaterial based antibacterial solutions. (Image: CKMNT)
Going one step further, there are efforts to replace antibiotics altogether with rapidly adaptable nanotherapeutics. They argue that recent advances in nanomaterials, genome sequencing, nucleotide synthesis, and bioinformatics could converge in nanotherapeutics with tailored sequence, specificity, and function that can overcome earlier challenges with small molecule-based approaches.
Nanosurgery
Nanosurgery tools hold the promise of studying or manipulating and repairing individual cells without damaging the cell. For instance, nanosurgery could remove or replace certain sections of a damaged gene inside a chromosome; sever axons to study the growth of nerve cells; or destroying an individual cell without affecting the neighboring cells.
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Return to Part 1: Nanotechnology in healthcare – Fitness monitoring, diagnostics and prevention
By
Michael
Berger
– Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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