Biomolecular Release from Alginate‐modified Electrode Triggered by Chemical Inputs Processed through a Biocatalytic Cascade – Integration of Biomolecular Computing and Actuation

Abstract

Biocatalytic cascades involving more than one or two enzyme‐catalyzed step are inefficient inside alginate hydrogel prepared on an electrode surface. The problem originates from slow diffusion of intermediate products through the hydrogel from one enzyme to another. However, enzyme activity can be improved by surface immobilization. We demonstrate that a complex cascade of four consecutive biocatalytic reactions can be designed, with the enzymes immobilized in an LBL‐assembled polymeric layer at the alginate‐modified electrode surface. The product, hydrogen peroxide, then induces dissolution of iron‐cross‐linked alginate, which results in release process of entrapped biomolecular species, here fluorescently marked oligonucleotides, denoted F‐DNA. The enzymatic cascade can be viewed as a biocomputing network of concatenated AND gates, activated by combinations of four chemical input signals, which trigger the release of F‐DNA. The reactions, and diffusion/release processes were investigated by means of theoretical modeling. A bottleneck reaction step associated with one of the enzymes was observed. The developed system provides a model for biochemical actuation triggered by a biocomputing network of reactions.

Dual‐responsive shape memory hydrogels with self‐healing and dual‐responsive swelling behaviors

“…In recent years, as natural hydrophilic polymers, polysaccharides, including sodium alginate, [49][50][51] carboxymethyl cellulose, 52 chitosan, 53 starch 54 and carrageenan, [55][56] have been widely utilized as starting materials for fabricating hydrogels due to their non-toxicity, biocompatibility, biodegradability, and renewability. [57][58][59] Sodium alginate is a natural polymer with multiple carboxyl groups, which have outstanding coordination capability with divalent or polyvalent metal cations, 60 and is a suitable material for preparing SMHs and intelligent hydrogels.…”

Not‐XOR (NXOR) Logic Gate Realized with Enzyme‐Catalyzed Reactions: Optical and Electrochemical Signal Transduction

“…The alternative application possible already at the present level of the technology relates to the special kind of binary (YES/NO) biosensing, where the multiple analytes are logically processed through biomolecular reactions without involving electronics. Other applications of small‐scale information processing systems based on biomolecular reactions bring us to novel areas with switchable “smart” materials controlled by logically processed biomolecular signals, switchable/tunable bioelectronic devices (e. g., biofuel cells) controlled by external signals, signal‐stimulated release processes, etc . Overall, the “negative” conclusions on applicability of biomolecular logic systems for computational applications are fully compensated by very positive conclusions on their applications in switchable “smart” materials and binary biosensing systems.…”

Boolean Logic Gates Realized with Enzyme‐catalyzed Reactions – Unusual Look at Usual Chemical Reactions

“…Overall, the research in molecular/biomolecular information processing, which has been motivated originally to progress unconventional computing applications, is broadly developing to areas not directly related to computing in its narrow definition. This research is bringing us to novel areas in sensing/biosensing, switchable “smart” materials controlled by logically processed signals, bioelectronic devices (e. g., biofuel cells) controlled by external signals,, signal‐controlled release processes, etc.…”

“…In the most studied experimental approaches, the enzyme systems carrying out Boolean logic operations were used in solutions, performing simple biocatalytic reactions ,. Recently, experiments have been reported with enzymes as the “gate machinery” immobilized on solid supports, or at interfaces, allowing their separation from the reacting species. It should be noted that this definition of the logic inputs and machinery part can be changed.…”