Automatic algorithmic driven monitoring of atrioventricular nodal re-entrant tachycardia ablation to improve procedural safety.

Background: During slow pathway modification for atrioventricular nodal reentrant tachycardia, heart block may occur if ablation cannot be stopped in time in response to high risk electrogram features (HREF).

Objectives: To develop an automatic algorithm to monitor HREF and terminate ablation earlier than human reaction.

Methods: Digital electrogram data from 332 ablation runs from February 2020 to June 2022 were included.

Anatomy of the proximal septal vein in patients with focal intramural ventricular arrhythmias.

Background: Focal ventricular arrhythmias (VAs) originating from the intramural myocardium of the basal septum are difficult to localize and ablate. Proximal septal veins emptying into the great cardiac vein can reach close to the origin of intramural arrhythmias.

Objective: To assess characteristics of proximal septal coronary veins in patients with intramural VAs.

Intramural mapping of intramural septal ventricular arrhythmias.

Background: Intramural ventricular arrhythmias (VAs) can originate in patients with or without structural heart disease. Electrogram (EGM) recordings from intramural sources of VA have not been described thoroughly.

Objective: We hypothesized that the presence of scar may be linked to the site of origin (SOO) of focal, intramural VAs.

Surgical ablation supplemented by ethanol injection for ventricular tachycardia refractory to percutaneous ablation.

Background: A combination of endocardial and epicardial approaches has improved the overall success rate of ventricular tachycardia (VT) ablation in patients with cardiomyopathy. However, the origins of some VTs are truly intramural or close to coronary arteries, which makes this combined strategy either prone to failure or too risky.

Objectives: This observational study aimed to explore the feasibility and efficacy of direct epicardial ablation combined with intramural ethanol injection via surgical approach for inaccessible intramural VTs or VTs too close to coronary arteries.

A multicenter randomized controlled trial of a modified Valsalva maneuver for cardioversion of supraventricular tachycardias.

Clinical Question: Valsalva maneuver is a recognized treatment for supraventricular tachycardia, but in clinical setting it has a low chance to achieve successful cardioversion. Studies suggested that the postural modification of valsalva maneuver may improve the rate of cardioversion. We further modified the maneuver and conduct a multicenter randomized controlled trial to test its efficacy.

A high-energy-density sugar biobattery based on a synthetic enzymatic pathway.

High-energy-density, green, safe batteries are highly desirable for meeting the rapidly growing needs of portable electronics. The incomplete oxidation of sugars mediated by one or a few enzymes in enzymatic fuel cells suffers from low energy densities and slow reaction rates. Here we show that nearly 24 electrons per glucose unit of maltodextrin can be produced through a synthetic catabolic pathway that comprises 13 enzymes in an air-breathing enzymatic fuel cell.

Cell-free Biosystems in the Production of Electricity and Bioenergy.

: Increasing needs of green energy and concerns of climate change are motivating intensive R&D efforts toward the low-cost production of electricity and bioenergy, such as hydrogen, alcohols, and jet fuel, from renewable sugars. Cell-free biosystems for biomanufacturing (CFB2) have been suggested as an emerging platform to replace mainstream microbial fermentation for the cost-effective production of some biocommodities. As compared to whole-cell factories, cell-free biosystems comprised of synthetic enzymatic pathways have numerous advantages, such as high product yield, fast reaction rate, broad reaction condition, easy process control and regulation, tolerance of toxic compound/product, and an unmatched capability of performing unnatural reactions.

In situ regeneration of NADH via lipoamide dehydrogenase-catalyzed electron transfer reaction evidenced by spectroelectrochemistry.

NAD/NADH is a coenzyme found in all living cells, carrying electrons from one reaction to another. We report on characterizations of in situ regeneration of NADH via lipoamide dehydrogenase (LD)-catalyzed electron transfer reaction to regenerate NADH using UV-vis spectroelectrochemistry. The Michaelis-Menten constant (K(m)) and maximum velocity (V(max)) of NADH regeneration were measured as 0.

Responsive interface switchable by logically processed physiological signals: toward "smart" actuators for signal amplification and drug delivery.

Biomarkers characteristic of liver injury, alanine transaminase and lactate dehydrogenase, were processed by an enzyme-based system functioning as a logic AND gate. The NAD+ output signal produced by the system upon its activation in the presence of both biomarkers was then biocatalytically converted to a decrease in pH. The acidic pH value biocatalytically produced by the system as a response to the biomarkers triggered the restructuring of a polymer-modified electrode interface.

Bacteria-based AND logic gate: a decision-making and self-powered biosensor.

We developed a bacteria-based AND logic gate using a Pseudomonas aeruginosa lasI/rhlI double mutant with two quorum-sensing signaling molecules as the input signals. We showed a distinct electrical output signal, despite the complexity and continuous regulation of metabolic reactions of living cells.

Self-powered biomolecular keypad lock security system based on a biofuel cell.

The enzyme-based keypad lock was integrated with a biofuel cell yielding a self-powered biomolecular information security system. The correct "password" introduced into the keypad lock resulted in the activation of the biofuel cell, while all other "wrong" permutations of the enzyme inputs preserved the "OFF" state of the biofuel cell.

Dual magnetobiochemical logic control of electrochemical processes based on local interfacial pH changes.

An electrode surface modified with a pH-sensitive polymeric brush was reversibly activated by local pH changes produced in situ by glucose oxidase associated with magnetic nanoparticles confined at the surface in the presence of an external magnet. The system mimics Boolean AND logic gate, with the magnetic and chemical input signals stimulating the electrochemical reactions at the switchable interface. Biomedical applications of the "smart" interface controlled by enzymatic reactions through local pH changes are anticipated in various implantable biomedical devices.

Reversible gating controlled by enzymes at nanostructured interface.

A nanostructured biocatalytic interface reversibly gating electrochemical reactions upon chemical signals processed by immobilized enzymes was architectured. The chemical signals were converted to local interfacial pH changes causing restructuring of the stimuli-responsive polymer and switching ON-OFF the electrochemical reaction.

Reversible "closing" of an electrode interface functionalized with a polymer brush by an electrochemical signal.

The poly(4-vinyl pyridine) (P4VP)-brush-modified indium tin oxide (ITO) electrode was used to switch reversibly the interfacial activity by the electrochemical signal. The application of an external potential (-0.85 V vs Ag|AgCl|KCl, 3M) that electrochemically reduced O(2) resulted in the concomitant consumption of hydrogen ions at the electrode interface, thus yielding a higher pH value and triggering the restructuring of the P4VP brush on the electrode surface.

Switchable selectivity for gating ion transport with mixed polyelectrolyte brushes: approaching 'smart' drug delivery systems.

A pH-responsive mixed polyelectrolyte brush from tethered polyacrylic acid (PAA) and poly(2-vinylpyridine) (P2VP) (PAA:P2VP = 69:31 by weight) was prepared and used for selective gating transport of anions and cations across the thin film. An ITO glass electrode was modified with the polymer brush and used to study the switchable permeability of the mixed brush triggered by changes in pH of the aqueous environment in the presence of two soluble redox probes: [Fe(CN)(6)](4-) and [Ru(NH(3))(6)](3+). The responsive behavior of the brush was also investigated using the in situ ellipsometric measurements of the brush swelling, examination of the brush morphology with atomic force microscopy (AFM), and contact angle measurements of the brush samples extracted from aqueous solutions at different pH values.

Biofuel cell logically controlled by antigen-antibody recognition: towards immune-regulated bioelectronic devices.

A switchable biofuel cell logically controlled by immune signals was developed as a model prototype for future adaptive implantable bioelectronic devices regulated by immune reactions. The cell demonstrated NOR Boolean logic operation in situ controlled by antibody signals.

Switchable electrode controlled by Boolean logic gates using enzymes as input signals.

Application of Boolean logic operations performed by enzymes to control electrochemical systems is presented. Indium-tin oxide (ITO) electrodes with the surface modified with poly-4-vinyl pyridine (P4VP) brush were synthesized and used as switchable electrochemical systems. The switch ON and OFF of the electrode activity were achieved by pH changes generated in situ by biocatalytic reactions in the presence of enzymes used as input signals.

Enzyme logic gates for the digital analysis of physiological level upon injury.

A biocomputing system composed of a combination of AND/IDENTITY logic gates based on the concerted operation of three enzymes: lactate oxidase, horseradish peroxidase and glucose dehydrogenase was designed to process biochemical information related to pathophysiological conditions originating from various injuries. Three biochemical markers: lactate, norepinephrine and glucose were applied as input signals to activate the enzyme logic system. Physiologically normal concentrations of the markers were selected as logic 0 values of the input signals, while their abnormally increased concentrations, indicative of various injury conditions were defined as logic 1 input.

Biofuel cell controlled by enzyme logic network--approaching physiologically regulated devices.

A "smart" biofuel cell switchable ON and OFF upon application of several chemical signals processed by an enzyme logic network was designed. The biocomputing system performing logic operations on the input signals was composed of four enzymes: alcohol dehydrogenase (ADH), amyloglucosidase (AGS), invertase (INV) and glucose dehydrogenase (GDH). These enzymes were activated by different combinations of chemical input signals: NADH, acetaldehyde, maltose and sucrose.

Bioelectrocatalytic system coupled with enzyme-based biocomputing ensembles performing boolean logic operations: approaching "smart" physiologically controlled biointerfaces.

The modified electrode for electrocatalytic oxidation of NADH was developed using a pH-switchable redox interface. The operation of the modified electrode was controlled by logic operations performed by enzyme systems processing biochemical input signals. The electrocatalytic oxidation of NADH was activated upon appropriate combinations of the signals processed by the AND/OR logic operations performed by the enzymes.

Switchable electrode controlled by enzyme logic network system: approaching physiologically regulated bioelectronics.

The logic network composed of three enzymes (alcohol dehydrogenase, glucose dehydrogenase, and glucose oxidase) operating in concert as four concatenated logic gates (AND/OR), was designed to process four different chemical input signals (NADH, acetaldehyde, glucose, and oxygen). The cascade of biochemical reactions culminated in pH changes controlled by the pattern of the applied biochemical input signals. The "successful" set of inputs produced gluconic acid as the final product and yielded an acidic medium, lowering the pH of a solution from its initial value of pH 6-7 to the final value of ca.

Biofuel cell controlled by enzyme logic systems.

An enzyme-based biofuel cell with a pH-switchable oxygen electrode, controlled by enzyme logic operations processing in situ biochemical input signals, has been developed. Two Boolean logic gates (AND/OR) were assembled from enzyme systems to process biochemical signals and to convert them logically into pH-changes of the solution. The cathode used in the biofuel cell was modified with a polymer-brush functionalized with Os-complex redox species operating as relay units to mediate electron transport between the conductive support and soluble laccase biocatalyzing oxygen reduction.