Most molecular probes used in biomedical research require dyes or fluorescence in order to obtain meaningful signals. These probes usually are quite limited with regard to the complexity of what they can image - be it the measurable concentration range or the number of molecules that can be simultaneously detected. This is an issue that is particularly relevant when it comes to track the simultaneous multiple molecular transformations that dictate complicated diseases like cancer. Scientists now have come up with an intriguing new class of molecular probes to solve this problem. They took an existing spectroscopic technique - surface-enhanced Raman scattering (SERS) - and developed a unique class of nanoparticle labels that provide for different responses when excited by laser light.
Extracellular signaling molecules are the language that cells use to communicate with each other. These molecules transfer information not only via their chemical compositions but also through the way they are distributed in space and time throughout the cellular environment. With the development of nanosensing techniques, scientists are trying to to eavesdrop on the cellular whisper and they getting closer to deciphering extracellular signaling - an important task in understanding how cells organize themselves, for instance during organ development or immune responses. Now, researchers have reported a novel sensing technique to interrogate extracellular signaling at the subcellular level. They developed a nanoplasmonic resonator array to enhance fluorescent immunoassay signals up to more than one hundred times to enable the first time submicrometer resolution quantitative mapping of endogenous cytokine secretion from an individual cell in nanoscale close to the cell.
Currently, when adult stem cells are harvested from a patient, they are cultured in the laboratory to increase the initial yield of cells and create a batch of sufficient volume to kick-start the process of cellular regeneration when they are re-introduced back into the patient. The process of culturing is made more difficult by spontaneous stem cell differentiation, where stem cells grown on standard plastic tissue culture surfaces do not expand to create new stem cells but instead create other cells which are of no use in therapy. New findings show that nanoscale patterning is a powerful tool for the non-invasive manipulation of stem cells. Their facile fabrication process employed, a range of thermoplastics that can be processed with exquisite reproducibility down to 5 nm fidelity using injection moulding approaches, offers unique potential for the generation of cell culture platforms for the up-scale of autologous cells for clinical use.
Silicone elastomers are widely used for biomedical applications and products. One major challenge for biomedical applications is to control the ingrowth of silicone-based implants and to avoid bacterial infections on device surfaces. The use of ions from metals like silver and copper is a promising, long-lasting method to achieve such bioactive effects. Researchers have now found a novel effect caused by a combination of copper and silver nanoparticles in silicone. By fabricating bioactive nanocomposite materials that release these ions in specific concentration levels and during a long time, manufacturers can control the bioactive effects of their medical devices or implants.
MicroRNAs (miRNAs) are short ribonucleic acid molecules, consisting of 21-25 nucleotide bases, that negatively regulate gene expression, also termed as gene silencing. Each miRNA is thought to regulate multiple genes, and since the human genome encodes hundreds of miRNAs, the potential regulatory circuitry afforded by miRNA is enormous. Recent discoveries suggest the association of specific miRNA sequences with a spectrum of diseases including cardiovascular and autoimmune diseases, as well as with a variety of cancers. It is therefore imperative, for diagnostics and prognostics, to accurately measure the expression levels of target miRNA molecules in patients' tissue samples or body fluids. To that end, researchers have developed an alternative way for the direct analysis of miRNAs in an array format, demonstrating fast and ultrasensitive detection of specific miRNAs.
It is widely believed that stem cell therapies have the potential to revolutionize the treatment of human diseases. Key to the success of such therapies are two crucial properties: the ability of stem cells to develop into any specialized cell type depending on the specific need at hand; and the ability to guide the fate of the stem cells by various external factors. Researchers in Asia have now demonstrated that graphene provides a promising biocompatible scaffold that does not hamper the proliferation of human mesenchymal stem cells and accelerates their specific differentiation into bone cells. The differentiation rate is comparable to the one achieved with common growth factors, demonstrating graphene's potential for stem cell research.
Superparamagnetic iron oxide nanoparticles (SPIONs) are emerging as promising candidates for various biomedical applications such as enhanced resolution imaging or targeted drug or gene delivery due to their biocompatibility, low cost of production, ability to immobilize biological materials on their surfaces, and potential for direct targeting using external magnets. Over the past few years, researchers demonstrated that magnetofection is an appropriate tool for rapid and specific gene transfection with low dose in vitro and site-specific in vivo applications. In new work, scientists in Australia have now successfully demonstrated the use of magnetofection for the delivery of malaria DNA vaccine.
Macrophages are white blood cells with a wide presence in various organs and tissues, that perform an essential role in keeping organisms healthy by scavenging cellular debris and disease agents. Since macrophages play an indispensable role in most pathological conditions, they represent an ideal target for therapeutic applications. Several approaches seeking to use macrophages for targeted therapies involve feeding therapeutic nanoparticles to macrophages ex vivo, followed by re-injection of the macrophages to target the diseased site. These techniques are often hampered by reduced drug release rates and drug degradation. Overcoming these limitations, scientists now report the ability of cellular backpacks to successfully encapsulate and controllably release drugs and avoid phagocytic internalization while remaining on the macrophage's surface.