Aptamer-conjugated, fluorescent gold nanorods as potential cancer theradiagnostic agents.

GNRs are emerging as a new class of probes for theradiagnostic applications thanks to their unique optical properties. However, the achievement of proper nanoconstructs requires the synthesis of highly pure GNRs with well-defined aspect ratio (AR), in addition to extensive surface chemistry modification to provide them with active targeting and, possibly, multifunctionality. In this work, we refined the method of the seed mediated growth and developed a robust procedure for the fabrication of GNRs with specific AR. We also revealed and characterized unexplored aging phenomena that follow the synthesis and consistently alter GNRs' final AR. Such advances appreciably improved the feasibility of GNRs fabrication and offered useful insights on the growth mechanism. We next produced fluorescent, biocompatible, aptamer-conjugated GNRs by performing ligand exchange followed by bioconjugation to anti-cancer oligonucleotide AS1411. In vitro studies showed that our nanoconstructs selectively target cancer cells while showing negligible cytotoxicity. As a result, our aptamer-conjugated GNRs constitute ideal cancer-selective multifunctional probes and promising candidates as photothermal therapy agents.

Clinical review: Consensus recommendations on measurement of blood glucose and reporting glycemic control in critically ill adults.

The management reporting and assessment of glycemic control lacks standardization. The use of different methods to measure the blood glucose concentration and to report the performance of insulin treatment yields major disparities and complicates the interpretation and comparison of clinical trials. We convened a meeting of 16 experts plus invited observers from industry to discuss and where possible reach consensus on the most appropriate methods to measure and monitor blood glucose in critically ill patients and on how glycemic control should be assessed and reported. Where consensus could not be reached, recommendations on further research and data needed to reach consensus in the future were suggested. Recognizing their clear conflict of interest, industry observers played no role in developing the consensus or recommendations from the meeting. Consensus recommendations were agreed for the measurement and reporting of glycemic control in clinical trials and for the measurement of blood glucose in clinical practice. Recommendations covered the following areas: How should we measure and report glucose control when intermittent blood glucose measurements are used? What are the appropriate performance standards for intermittent blood glucose monitors in the ICU? Continuous or automated intermittent glucose monitoring - methods and technology: can we use the same measures for assessment of glucose control with continuous and intermittent monitoring? What is acceptable performance for continuous glucose monitoring systems? If implemented, these recommendations have the potential to minimize the discrepancies in the conduct and reporting of clinical trials and to improve glucose control in clinical practice. Furthermore, to be fit for use, glucose meters and continuous monitoring systems must match their performance to fit the needs of patients and clinicians in the intensive care setting.

Increasing the trapping efficiency of particles in microfluidic planar platforms by means of negative dielectrophoresis.

We present a novel planar electrode geometry in which particles (typically 10 microm in diameter) are focused near a defined surface before being trapped using negative dielectrophoresis. The focusing element can deflect particles having speeds up to hundreds of micrometers per second. This trapping configuration results in improved trapping yields and a decrease in overall reagent consumption. Particles are trapped dynamically while flowing in a microfluidic channel.

Cell-bionics: tools for real-time sensor processing.

The accurate monitoring of the physiological status of cells, tissues and whole organisms demands a new generation of devices capable of providing accurate data in real time with minimal perturbation of the system being measured. To deliver on the promise of cell-bionics advances over the past decade in miniaturization, analogue signal processing, low-power electronics, materials science and protein engineering need to be brought together. In this paper we summarize recent advances in our research that is moving us in this direction. Two areas in particular are highlighted: the exploitation of the physical properties inherent in semiconductor devices to perform very low power on chip signal processing and the use of gene technology to tailor proteins for sensor applications. In the context of engineered tissues, cell-bionics could offer the ability to monitor the precise physiological state of the construct, both during 'manufacture' and post-implantation. Monitoring during manufacture, particularly by embedded devices, would offer quality assurance of the materials components and the fabrication process. Post-implantation monitoring would reveal changes in the underlying physiology as a result of the tissue construct adapting to its new environment.

SERS platforms for high density DNA arrays.

Surface Enhanced Raman Scattering (SERS) gives rise to analytical applications with much promise. In our approach three steps are necessary. We require a SERS platform of high enhancement. This has been achieved using the special technique of Island Lithography, combined with Ag deposition by galvanic exchange, yielding an enhancement factor of 10(8). Probe oligonucleotide molecules are attached to a specific area on the platform, at the optimized surface concentration, using thiolated single stranded (ss) DNA molecules. The optimum surface concentration has been determined and interpreted in the light of the polyelectrolyte behaviour of ssDNA. Finally the change in SERS produced by hybridisation of the probe molecules to a target DNA molecule is measured. Highly discernible changes have been obtained. No change in probe signal is seen when presented with one base mismatched target. From this work it is concluded that the prospects for label-free DNA detection in high-density arrays is now close to achievement.

Biotechnology. Paper Alert.

A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in biotechnology.