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Editorial, Seminars in Cell & Developmental Biology
It is a pleasure to introduce this special edition of Cell and Development
Biology dedicated to the field and application of Biosensors. This edition
comprises seven reviews covering the most active research areas where we believe
some of the most prominent advances in the field are likely to emerge in the
near to medium term. In line with scope of this journal, some emphasis is given
towards techniques applicable to Cell Biology
Carrier systems and biosensors for biomedical applications.
This chapter addresses both carrier systems and biosensors which are often
applied directly to tissues, either as skin patches, implanted or ingested by a
variety of routes. It follows that there is a common theme between these
applications and many of those discussed elsewhere within this book. Any device,
scaffold or implant within the body must usually display extreme
biocompatibility if it is not to cause harm to the patient. The techniques of
tailoring surfaces to ensure no adverse reactions are a common theme running
throughout this work on tissue engineering
Energy storage for a lunar base by the reversible chemical reaction: CaO+H2O reversible reaction Ca(OH)2
A thermochemical solar energy storage concept involving the reversible reaction CaO + H2O yields Ca(OH)2 is proposed as a power system element for a lunar base. The operation and components of such a system are described. The CaO/H2O system is capable of generating electric power during both the day and night. The specific energy (energy to mass ratio) of the system was estimated to be 155 W-hr/kg. Mass of the required amount of CaO is neglected since it is obtained from lunar soil. Potential technical problems, such as reactor design and lunar soil processing, are reviewed
On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology
The DiComp Shunting Dielectric Sensor (SDS) is a new patent-pending technology developed under the Small Business Innovation Research Program (SBIR) for NASA's Kennedy Space Center. The incorporation of a shunt electrode into a conventional fringing field dielectric sensor makes the SDS uniquely sensitive to changes in material dielectric properties in the KHz to MHz range which were previously detectable only at GHz measurement frequencies. The initial NASA application of the SDS for Nutrient Delivery Control has demonstrated SDS capabilities for thickness and concentration measurement of Hoagland nutrient solutions. The commercial introduction of DiComp SDS technology for concentration and percent solids measurements in dispersions, emulsions and solutions represents a new technology for process measurements for liquids in a variety of industries
Sonochemically fabricated microelectrode arrays for biosensors. Part II. Modification with a polysiloxane coating
A polymer modified sonochemically fabricated glucose oxidase microelectrode
array with microelectrode population densities of up to 2.5 x 105
microelectrodes cm-2 is reported. These microelectrode sensors were formed by
first depositing an insulating film on commercial screen printed electrodes
which was subsequently sonicated to form cavities of regular sizes in the film.
Electropolymerisation of aniline at the microelectrode cavities formed
polyaniline protrusions containing entrapped glucose oxidase. Chemical
deposition of polysiloxane from dichlorodimethysilane was used to deposit a thin
protective and diffusion mass transport controlling coating over the electrodes.
The physical and electrochemical properties of these films were studied. The
performance of the final glucose oxidase based microelectrode sensor array is
reported
Flexible Ultrathin PolyDVB/EVB Composite Membranes for the Optimization of a Whole Blood Glucose Sensor.
An ultrathin composite membrane has been developed as the outer covering barrier
in a model amperometric glucose oxidase enzyme electrode. The membrane was
formed by cathodic electropolymerization of divinylbenzene/ethylvinylbenzene at
the surface of a gold coated polyester support membrane. Permeability
coefficients were determined for O2 and glucose across membranes with a range of
polymer thicknesses. Anionic interferents (such as ascorbate), were screened
from the working electrode via a charge exclusion mechanism. The enzyme
electrode showed an initial 10% signal drift when first exposed to whole human
blood over a period of 2 hours, after which responses remained essentially
stable. Whole blood patient glucose determinations yielded a correlation
coefficient of r2=0.99 compared to standard hospital analyses
Electrochemical Aptasensor for Detection of Dopamine
This work presents a proof of concept of a novel, simple, and sensitive method of detection of dopamine, a neurotransmitter within the human brain. We propose a simple electrochemical method for the detection of dopamine using a dopamine-specific aptamer labeled with an electrochemically active ferrocene tag. Aptamers immobilized on the surface of gold screen-printed gold electrodes via thiol groups can change their secondary structure by wrapping around the target molecule. As a result, the ferrocene labels move closer to the electrode surface and subsequently increase the electron transfer. The cyclic voltammograms and impedance spectra recorded on electrodes in buffer solutions containing different concentration of dopamine showed, respectively, the increase in both the anodic and cathodic currents and decrease in the double layer resistance upon increasing the concentration of dopamine from 0.1 to 10 nM L-1. The high affinity of aptamer-dopamine binding (KD ≈ 5 nM) was found by the analysis of the binding kinetics. The occurrence of aptamer-dopamine binding was directly confirmed with spectroscopic ellipsometry measurements
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