Tony Cass

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.See related commentary by Soto-Rivera and Agus, http://ccforum.com/content/17/3/155

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.

Protein Engineering for Biosensors

In Chapter 2, we introduced the basic concept of electrochemical sensors and biosensors. In this chapter, we will focus on the biological aspects of biosensors in two important regards; the first being the biological molecules involved in the molecular recognition process that gives the biosensors their specificity and sensitivity as illustrated in Figure 3.1 [1]. We will discuss how these proteins can be engineered to improve sensor performance. The second aspect is concerned with biocompatibility, which is the mutual interaction between the sensor and the tissue within which it is located. Although progress has been made in making implantable biosensors reliable and robust over a period of days, there are still significant technical issues associated with long-term (weeks to months) implantation. This reflects in part the response of the tissue to trauma and in part the inherent robustness of the biological molecules used in the sensor. This implies that the solution to long-term implantation will come from a combination of factors including minimally invasive implantation, understanding and modulating tissue response to implantation, and modifying the properties of the biomolecules. Molecular recognition occurring at or near the sensor surface can be transduced through a variety of different physical sensing modalities and this leads to a sensor classification shown below.

8×16 channel physiological monitoring platform of stem cell culture systems

An up to 128 channel PC-based physiological measurement platform for stem cell cultures is presented in this paper. The platform is designed to measure the most important stem cell culture parameters namely pH, temperature and glucose in real-time. The aim is to optimize the whole bioprocess by means of the acquisition of real-time, on-line, in-situ quantitative physiology information from the culture. The hardware system of the physiological measurement platform is designed in a modular manner. Each is designed as an independent 16 channel data acquisition system specific to a sensor type. Up to eight data acquisition modules are connected together and then connected to the host PC to form the 8times16 channel physiological measurement platform. The host PC is mainly used for data acquisition process control. With the virtual instrumentation application software programmed in LabVIEW, the user-friendly interface of physiological measurement platform is easy to use in facilitating the acquisition, display and management different types of physiological data. The platform is generic by design and can be interfaced with a variety of potentiometric and amperometric sensors. This operational attributes renders the platform suitable for any cell culture application where quality control is needed through the quantitative monitoring of the bioprocess and its subsequent informed assessment and interpretation. Furthermore, the modular structure facilitates the introduction of new sensor to the platform.