Modifying living cell by coating them with a nanolayer of functional materials in order to provide them with new structural and functional features has developed into a popular research area for bionanotechnology researchers. In contrast to genetic manipulation techniques, here the functionality of a cell is modified simply by attaching polymers or nanoparticles to the cell's surface. A recent Perspective paper covers the most interesting and promising work in this area and presents an outlook the major potential future directions. The article focuses on on cell encapsulation with Layer-by-Layer (LbL) self-assembly via sequential adsorption of oppositely charged components: polyelectrolytes, nanoparticles, and proteins.
Researchers in China showed that nanoparticles smaller than 10 nm in diameter accumulate more efficiently and penetrate more deeply in tumors relative to their larger counterparts. Their findings have significant implications for the development of nanomaterials to diagnose and treat cancer. The enhanced tumor accumulation of the ultrasmall nanoparticles may be due, at least in part, to their prolonged blood circulation time. In contrast, most nanomaterials that enter the blood are rapidly cleared by tissue-resident macrophages in the liver and spleen. Ultimately, the ability of ultrasmall nanoparticles to diffuse deep within the tumor bulk may enable the design of nanoparticles that can carry therapeutic and diagnostic agents more efficiently into tumors.
Candida albicans is a leading fungal cause of burn infections in hospital settings. The prevalence of invasive candidiasis in burn cases varies widely, but it accounts as high as 23% of severe infection with a mortality rate ranging from anywhere to 14% to 70%. In a recent pre-clinical study, a nitric oxide releasing nanoparticle platform, which has previously been shown to be antibacterial to both gram positive and negative bacteria, as well as an accelerator of wound healing in excisional animal models, was found to be efficacious in clearing candidal burn infections in mice. This study represents one of many pre-clinical investigations demonstrating the efficacy of the NO nanoparticles as a broad spectrum antimicrobial agent as well as wound healing accelerant.
Wound healing is an exceedingly complex process, involving a multitude of signaling pathways, effector molecules, response phases, as well as a moderated balance between all these components. Nitric oxide (NO) plays a critical role in the wound-healing process via antimicrobial properties, modulation of platelet/cytokine function, vasodilatory effects, and promotion of angiogenesis and matrix deposition. While attempts to administer NO to wound areas have shown some promise, the current modalities all suffer from varying drawbacks, such as administration site irritation or the burden of large, expensive equipment. Researchers have now introduced a nanoparticle platform comprised of silane based sol-gel and sugar-derived glasses that can generate, store, and deliver NO in a controlled and sustained manner is utilized to enhance wound healing in immunodeficient mice.
Nanotechnology offers new strategies to enable minimally invasive and localized approaches for diagnosing and treating cancer, thereby avoiding the serious side effects and shortcomings of chemotherapy. For instance, it has been shown that often less than 1% of the administered drug molecules during chemotherapy enter tumor cells and bind to the nuclear DNA. Another complication is drug resistance of cancer cells. This actually is one of the main causes of failure in the treatment of cancer. Cancer researchers are looking to nanoparticles as a drug carrier capable of localizing and directly releasing drugs into the cell nucleus, leading to a high therapeutic efficacy. Although increased therapeutic efficacy has been realized, there have been no reports on visualizing at nanoscale dimensions how nanoparticles interact with specific organelles. In a new breakthrough for nanomedicine cancer research, scientists have now reported the direct visualization of interactions between drug-loaded nanoparticles and the nucleus of a cancer cell.
Green Fluorescent Protein (GFP) - originally found in a jellyfish - has played a crucial role in life science research, providing insights to many fundamental questions that have paved the way to the biology and medicine of the future. Since the mid-1990s, when the protein was successfully cloned, GFP can be found in research laboratories worldwide used as a visual marker of gene expression and protein localization, easily observed via light (optical) microscopy. GFP can be linked to other proteins and is primarily used to track dynamic changes in living cells. In 2008, biologists who discovered and developed the protein as a laboratory tool won a Nobel Prize for their work. Researchers in Spain have now demonstrated how GFP can also act as an efficient nano-thermometer inside cells.
The Venus flytrap (Dionaea muscipula) is a carnivorous plant that catches and digests little insects. Its trapping mechanism consists of a series of tiny hairs at the crease where the plant's two leaves join. When a fly or spider walk across these hairs, touching two or more of them in succession, the two leaves will close quickly enough - within hundreds of milliseconds - to prevent its escape. Now, researchers have used it as inspiration for a new biomimetic robot made with artificial muscles. The device offers promise in the development of electrically stimulated artificial muscle that could be implanted in people to help overcome muscular disease or paralysis.
Carbon nanotubes, like the nervous cells of our brain, are excellent electrical signal conductors and can form intimate mechanical contacts with cellular membranes, thereby establishing a functional link to neuronal structures. There is a growing body of research on using nanomaterials in neural engineering. Now, researchers have, for the first time, explored the impact of carbon nanotube scaffolds on multilayered neuronal networks. Up to now, all known effects of carbon nanotubes on neurons - namely their reported ability to potentiate neuronal signaling and synapses - have been described in bi-dimensional cultured networks where nanotube/neuron hybrids were developed on a monolayer of dissociated brain cells.