How evolutionary is nanomedicine in therapeutics? Is it worth all the hype? Can we, as engineers, find opportunities in the field of nanomedicine? Well, I hope this article will answer many similar questions.
Nanotechnology and its manifestation in Medicine
Let’s start with the understanding of how exactly is nanotechnology playing a noteworthy role in the field of medicine. From its very dawn, nanotechnology has indeed shaped the fundamental industrial applications such as manufacturing, biotechnology, semiconductors and fabrication of work area from micro to large- scale prospects. The impact of nanotechnology on the medical domain is well pronounced and the results can be pointed out at biosensors, nanosized microchips, modified liposomal action and mainly the ease brought in the fields of treatment and diagnosis of diseases.
Why use Nanotechnology for Drug delivery?
If the goal of research on nanotechnology is just to make something nano, new, and more complicated, the goal is achieved as seen from the progress made in the last decade, at least in part. The ultimate goal of any research in drug delivery, however, must be to develop drug-delivery systems, nanoparticulate systems in this case, to prevent, to control, and to treat debilitating diseases. Most scientists working in the pharmaceutical and biotechnology sectors, as well as in academia, want to develop nanoparticle formulations that can deliver drugs more effectively to the target site for enhanced efficacy and reduced side effects.
Nanoparticles offer important multifunctional platforms for biomedical applications. Varieties of nanoparticles, such as silica nanoparticles, quantum dots, metal nanoparticles, and lanthanide nanoparticles, have unique properties which are adapted for different applications in the bio-analysis field. Nanoparticles not only ensure the drug delivery but also the confirmation of target site (commonly tumors). A new challenge of essentially tracking down the nanomedicine from systemic to subcellular level is posed which is swept off with the use of fluorescent markers, those being detectable during diagnostic assays.
Various examples in different forms include:
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Fe3O4 nanocrystals on uniform dye-doped mesoporous silica nanoparticles to be used as a contrast agent in magnetic resonance imaging and loaded doxorubicin in the pores.
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Histidine-tagged cyan fluorescent protein-capped magnetic mesoporous silica nanoparticles system was fabricated for drug delivery and fluorescent imaging.
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Quantum dots are small-sized (1–10 nm) semiconductor nanocrystals composed of the inorganic elemental core (e.g., Cd and Se) surrounded by a metallic shell (ZnS). They are widely used in biological research and can also be used as drug carriers or simply as fluorescent labels for other drug carriers remain highlighted.
Other notable advancements include usage of iron oxide and gold nanoparticles due to the presence of surface plasmons which make the nanoparticles to absorb light in the visible region, making it possible to study their size-dependent light absorption through surface plasmon resonance (SPR). In terms of biocompatibility and non-cytotoxicity, gold nanoparticles as approved by the Food and Drug Administration(FDA) have distinct advantages over other metallic particles and could also be utilized as a favorable carrier for delivery of drugs. These nanoparticles can be conjugated with amino acid and proteins. Fabrication of gold nanoparticles and functionalization with organic molecules to interact with any physiological system are more important. These functionalized nanoparticles are a promising candidate for drug delivery as biomarkers of the drug-resistant cancer cell. Reported application of gold nanoparticles includes insulin delivery by nasal route, improved antimicrobial action against E. coli strains and ciprofloxacin- protected nanoparticles for better drug release.
Misconceptions and Limitations:
Yes, though nanobiotechnological advancements are a promising outcome, it is not all that it looks like. Nanotechnology fever was fueled by an observation of the behavior of nanoparticles in tumors in mice, known as the enhanced permeation and retention (EPR) effect. The EPR effect is considered to be responsible for increased delivery of nanoparticles to targeted tumors in mouse experiments. This notion evolved into an idea that only nanoparticles have the EPR effect. Careful analysis of the original data, however, indicates that albumin and IgG are actually better in accumulating at the tumor site.
The enhanced EPR effect of PEGylated nanoparticles was thought to be due to the increased circulation cycles. Thus, it has been widely assumed that PEGylated nanoparticles having the EPR effect will result in an enhanced tumor-killing effect, and therefore, the problem of targeted drug delivery to tumors was partially solved. The reality is that these assumptions have produced numerous research articles, but have made no significant advances in translation into patient treatment
Nanoparticle formulations, as compared with solution formulations, increase the drug concentration around a tumor by 100–400%. These increases are phenomenal by any measure. What is missing here, however, is the big picture showing the full story on drug delivery. It should be understood that >95% of the administered nanoparticles end up at sites other than the targeted tumor; this fact has been largely overlooked. Nanoparticles may provide an alternative way of making aqueous solution formulations for intravenous administration of poorly soluble drugs without using undesirable excipients. This is a great use of nanoparticle approaches. It is simply different than the widely believed notion that nanoparticles would be far superior to non-particulate solution formulations.
Future Opportunities:
Nanoparticles are rapidly becoming the focus of most efforts aiming at targets and site-specific drug delivery. The targeting ability of nanoparticles depends on certain factors such as particle size, surface charge, surface modification and hydrophobicity. Still many problems related to selective binding, targeted delivery and toxicity need to be overcome. Limited knowledge about the toxicity of nanoparticles is a major concern and certainly deserves more attention. If these nanoparticles are cautiously designed to tackle problems related to target and route of administration, they may lead to a new more successful paradigm in the world of therapeutics and research. The most promising research in nanoparticle production is via using supercritical fluids which are environmentally friendly and free of toxic solvents. Much research is currently being performed to overcome these hurdles which will definitely establish nanoparticle-based drug delivery as the gold standard for site-specific therapeutics. Though ample optimizations are existing in the field nanotechnological research in the medical field is an evergreen opportunity.
