Biomedical subjects

C Dumschat

Publications and source records attributed to C Dumschat.

3 recordsLinked to original sources

PubMed1999

A disposable biosensor for urea determination in blood based on an ammonium-sensitive transducer.

A potentiometric urea-sensitive biosensor using a NH4(+)-sensitive disposable electrode in double matrix membrane (DMM) technology as transducer is described. The ion-sensitive polymer matrix membrane was formed in the presence of an additional electrochemical inert filter paper matrix to improve the reproducibility in sensor production. The electrodes were prepared from one-side silver-coated filter paper, which is encapsulated for insulation by a heat-sealing film. A defined volume of the NH4(+)-sensitive polymer matrix membrane cocktail was deposited on this filter paper. To obtain the urea-biosensor a layer of urease was cast onto the ion-sensitive membrane. Poly (carbamoylsulfonate) hydrogel, produced from a hydrophilic polyurethane prepolymer blocked with bisulfite, served as immobilisation material. The disposable urea sensitive electrode was combined with a disposable Ag/AgCl reference electrode to obtain the disposable urea biosensor. The sensor responded rapidly and in a stable manner to changes in urea concentrations between 7.2 x 10(-5) and 2.1 x 10(-2)mol/l. The detection limit was 2 x 10(-5) mol/l urea and the slope in the linear range 52 mV/decade. By taking into consideration the influence of the interfering K(+)- and Na(+)-ions the sensor can be used for the determination of urea in human blood and serum samples (diluted or undiluted). A good correlation was found with the data obtained by the spectrophotometric routine method.

Biosensing Techniques↗

PubMed1998

Wearable microdialysis system for continuous in vivo monitoring of glucose.

We developed a new system to monitor glucose continuously in vivo. The miniaturised system is very easy to handle and was optimised to a resource-saving working modus. Sampling was performed by means of a biocompatible microdialysis needle probe inserted into the subcutaneous tissue. During glucose tolerance tests the results of our monitoring system were correlated with the glucose level of the venous blood stream. A comparison according to the procedure known as 'error grid analysis' provided an excellent correlation between the two completely independent analyses systems with the reference determination results. All values obtained with our systems were clinically correct or at least clinically acceptable.

Blood Glucose Self-Monitoring↗

PubMed1994

Glucose sensor in containment technology.

A new transducer concept for miniaturized immobilized enzyme glucose sensors is presented. The enzyme containing membrane is anchored inside the microcontainment of a silicon chip together with the metal electrode. Containment based sensors are ideally suited for integration into microsystems. The fabrication process is planned as a full wafer process allowing transfer to low-cost mass-production with a narrow variability. The functionality of the containment concept is demonstrated by the fabrication of chips with single GOD-based amperometric glucose sensors which have been tested in glucose solution. The advantages of the containment technology are discussed.

Biosensing Techniques↗