10 research outputs found
Realization and Properties of Biochemical-Computing Biocatalytic XOR Gate Based on Enzyme Inhibition by a Substrate
We consider a realization of the XOR logic gate in a process biocatalyzed by
an enzyme (here horseradish peroxidase: HRP), the function of which can be
inhibited by a substrate (hydrogen peroxide for HRP), when the latter is
inputted at large enough concentrations. A model is developed for describing
such systems in an approach suitable for evaluation of the analog noise
amplification properties of the gate. The obtained data are fitted for gate
quality evaluation within the developed model, and we discuss aspects of
devising XOR gates for functioning in "biocomputing" systems utilizing
biomolecules for information processing
Who Shot the Bullet? Projectile Composition Characterization as an Evolutionary Method for Enhancement of Ballistics Evidence Analysis
Biochemical Filter with Sigmoidal Response: Increasing the Complexity of Biomolecular Logic
Multianalyte Digital Enzyme Biosensors with Built-in Boolean Logic
Multianalyte Digital Enzyme
Biosensors with Built-in Boolean Logi
Keypad Lock Security System Based on Immune-Affinity Recognition Integrated with a Switchable Biofuel Cell
An immune-based biorecognition system mimicking a keypad lock device was integrated with a switchable biofuel cell resulting in the power output change upon the correct input of the āpasswordā encoded in the antibody-sequence
Realization of Associative Memory in an Enzymatic Process: Toward Biomolecular Networks with Learning and Unlearning Functionalities
We report a realization of an associative memory signal/information
processing system based on simple enzyme-catalyzed biochemical reactions.
Optically detected chemical output is always obtained in response
to the triggering input, but the system can also ālearnā
by association, to later respond to the second input if it is initially
applied in combination with the triggering input as the ātrainingā
step. This second chemical input is not self-reinforcing in the present
system, which therefore can later āunlearnā to react
to the second input if it is applied several times on its own. Such
processing steps realized with (bio)Āchemical kinetics promise applications
of bioinspired/memory-involving components in ānetworkedā
(concatenated) biomolecular processes for multisignal sensing and
complex information processing
Artificial Muscle Reversibly Controlled by Enzyme Reactions
Chemically induced actuation of a polypyrrole (Ppy) artificial muscle was controlled by biocatalytic reactions, resulting in changes in the redox state of the polymer film mediated by soluble redox species. The biocatalytic process triggered by diaphorase in the presence of NADH resulting in the reduction of the Ppy film was reflected by the potential shift in the negative direction generated in the film. Conversely, the biocatalytic process driven by laccase in the presence of O<sub>2</sub> resulted in the oxidation of the Ppy film, thus yielding the positive potential shift. Both reactions produced opposite bending of the Ppy flexible strip, allowing reversible actuation controlled by the biocatalytic processes. The biocatalytic reactions governing the chemical actuator can be extended to multistep cascades processing various patterns of biochemical signals and mimicking logic networks. The present chemical actuator exemplifies the first mechanochemical device controlled by biochemical means with the possibility to scale up the complexity of the biochemical signal-processing system
Implanted Biofuel Cell Operating in a Living Snail
Implantable biofuel cells have been suggested as sustainable
micropower
sources operating in living organisms, but such bioelectronic systems
are still exotic and very challenging to design. Very few examples
of abiotic and enzyme-based biofuel cells operating in animals in
vivo have been reported. Implantation of biocatalytic electrodes and
extraction of electrical power from small living creatures is even
more difficult and has not been achieved to date. Here we report on
the first implanted biofuel cell continuously operating in a snail
and producing electrical power over a long period of time using physiologically
produced glucose as a fuel. The āelectrifiedā snail,
being a biotechnological living ādeviceā, was able to
regenerate glucose consumed by biocatalytic electrodes, upon appropriate
feeding and relaxing, and then produce a new āportionā
of electrical energy. The snail with the implanted biofuel cell will
be able to operate in a natural environment, producing sustainable
electrical micropower for activating various bioelectronic devices
Biomolecular Filters for Improved Separation of Output Signals in Enzyme Logic Systems Applied to Biomedical Analysis
Biomolecular logic systems processing biochemical input signals and producing ādigitalā outputs in the form of YES/NO were developed for analysis of physiological conditions characteristic of liver injury, soft tissue injury, and abdominal trauma. Injury biomarkers were used as input signals for activating the logic systems. Their normal physiological concentrations were defined as logic-0 level, while their pathologically elevated concentrations were defined as logic-1 values. Since the input concentrations applied as logic 0 and 1 values were not sufficiently different, the output signals being at low and high values (0, 1 outputs) were separated with a short gap making their discrimination difficult. Coupled enzymatic reactions functioning as a biomolecular signal processing system with a built-in filter property were developed. The filter process involves a partial back-conversion of the optical-output-signal-yielding product, but only at its low concentrations, thus allowing the proper discrimination between 0 and 1 output values
Electrochemically Controlled Drug-Mimicking Protein Release from Iron-Alginate Thin-Films Associated with an Electrode
Novel biocompatible hybrid-material composed of iron-ion-cross-linked
alginate with embedded protein molecules has been designed for the
signal-triggered drug release. Electrochemically controlled oxidation
of Fe<sup>2+</sup> ions in the presence of soluble natural alginate
polymer and drug-mimicking protein (bovine serum albumin, BSA) results
in the formation of an alginate-based thin-film cross-linked by Fe<sup>3+</sup> ions at the electrode interface with the entrapped protein.
The electrochemically generated composite thin-film was characterized
by electrochemistry and atomic force microscopy (AFM). Preliminary
experiments demonstrated that the electrochemically controlled deposition
of the protein-containing thin-film can be performed at microscale
using scanning electrochemical microscopy (SECM) as the deposition
tool producing polymer-patterned spots potentially containing various
entrapped drugs. Application of reductive potentials on the modified
electrode produced Fe<sup>2+</sup> cations which do not keep complexation
with alginate, thus resulting in the electrochemically triggered thin-film
dissolution and the protein release. Different experimental parameters,
such as the film-deposition time, concentrations of compounds and
applied potentials, were varied in order to demonstrate that the electrodepositon
and electrodissolution of the alginate composite film can be tuned
to the optimum performance. A statistical modeling technique was applied
to find optimal conditions for the formation of the composite thin-film
for the maximal encapsulation and release of the drug-mimicking protein
at the lowest possible potential