For the treatment of eye conditions, conventional eye drops have three major disadvantages: they must be applied frequently; their ocular bioavailability is low (i.e. less than 5% of the administered active is absorbed or becomes available at the site of physiological activity); and, their use is often associated with high systemic exposure to actives. The common alternative option, ophthalmic inserts, achieve sustained drug delivery but suffer from other limitations: they are difficult to insert (especially for the elderly and others with visual impairment) and easy to misapply; they are easily expulsed from the eye; patient compliance is low (discomfort and blurring of vision, difficulty of insertion, need for removal at the end of their useful life); and, they are costly to manufacture. Researchers in the UK believe that biodegradable polymer nanoparticles show great promise as drug delivery devices for the eye. They have developed well-tolerated systems that combine the sustained release characteristics of inserts with the patient acceptability of conventional eye drops.
Bioactive glass is currently regarded as the most biocompatible material in the bone regeneration field because of its bioactivity, osteoconductivity (ability of a scaffold to support cell attachment and subsequent bone matrix deposition and formation) and even osteoinductivity (a scaffold that encourages osteogenic precursor cells to differentiate into mature bone-forming cells). However, the formulation of bioactive glass has been limited to bulk, crushed powders and micronscale fibers. Now, researchers in South Korea and the UK have for the first time fabricated bioactive glass in nanofibrous form. This material, which shows excellent bioactivity, is likely to open the door to the development of new nano-structured bone regeneration materials for regenerative medicine and tissue engineering.
A number of neurodegenerative disorders, such as Parkinson's or Alzheimer Disease, may potentially be treated by gene therapy, i.e. the delivery of therapeutic genes to neurons. Currently, the most common carrier molecules to deliver the therapeutic gene to the patient's target cells are viruses that have been genetically altered to carry normal human DNA. Overall gene delivery efficiency is typically low for nonviral vectors. New research undertaken at The Johns Hopkins University offers a systematic approach to understanding the gene delivery process in neurons and explores the intracellular barriers to nonviral gene delivery and possible ways to improve their effectiveness.
A new study presents a viable strategy to stabilize enzymes under conditions found in real world biocatalytic applications. This stabilization of proteins through gold nanoparticles occurs through two mechanisms: 1) binding of the protein in its active structure stabilizes that structure; 2) the gold particles lower the interfacial energy between air and water, thus diminishing the driving force for denaturation. The result is a functional biocatalyst that can be readily applied to biotechnological applications.
Nanoribbons, which are attracting much attention due to their well-defined geometry and perfect crystallinity, require complex and expensive equipment to faricate. Researchers in China have succeeded in fabricating a single nanoribbon sensor and demonstrated its use as a potential in situ monitor to track blood glucose levels, suitable for potential use by diabetics.
Nanoscale sensors based on silicon nanowires and carbon nanotubes are capable of detecting molecules at ultra low concentrations. The potential applications include early detection of cancer and fast sequencing of genome. However, for these applications, the time taken by the sensor to reach stable response is crucial. This time is dictated by the diffusion of molecules (e.g. cancer markers) through the solution and their subsequent capture at the sensor surface. Researchers at Purdue University show that this response is governed by the geometry of diffusion of the system and that nanobiosensors are capable of detecting bio-molecules at much lower concentration than the classical planar sensors.
Multidrug resistance, the principal mechanism by which many cancers develop resistance to chemotherapy drugs, is a major factor in the failure of many forms of chemotherapy. New research by Chinese scientists suggests that nanoparticle surface chemistry and size as well as the unique properties of the magnetic nanoparticles themselves may contribute to a synergistic enhanced effect of drug uptake of targeted cancer cells. These findings could result in promising biomedical applications for cancer therapy.
The controlled release of biomolecules or nanoparticles is a problem of general interest for a wide range of applications. Researchers at Johns Hopkins University in Baltimore have demonstrated the programmed release, by applying a small voltage pulse, of biomolecules and nanoparticles chemically tethered to patterned electrode arrays.