Pyrolyzed Walnut Shell-Based Flexible Electrodes for Magnetically Triggered ON/OFF DNA Release

Paolo Bollella; Blanca Cassano; Verdiana Marchianò; Angelo Tricase; Eleonora Macchia; Luisa Torsi

doi:10.1002/anbr.202500131

Pyrolyzed Walnut Shell-Based Flexible Electrodes for Magnetically Triggered ON/OFF DNA Release

Paolo Bollella^*
, Blanca Cassano
, Verdiana Marchianò
, Angelo Tricase
, Eleonora Macchia
, Luisa Torsi^*

^*Corresponding author for this work

Physics

Research output: Contribution to journal › Article › Scientific › peer-review

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Abstract

A magnetically gated, enzymatically driven DNA release platform based on sustainable pyrolyzed walnut shell-derived carbon electrodes is reported. Upon glucose addition under aerobic conditions, biocatalytic oxygen reduction at the cathode induces a local pH increase, resulting in electrostatic repulsion of negatively charged 5(6)-carboxyfluorescein-labeled DNA (FAM-labeled DNA). Electrochemical analysis reveals an oxygen reduction reaction (ORR) onset potential of +0.576 ± 0.003 V vs. Ag/AgCl and a maximum current of −8.2 ± 0.4 μA. Electrochemical impedance spectroscopy (EIS) confirms a post-ORR increase in interfacial resistance from 6.2 ± 0.5 to 11.1 ± 0.9 kΩ. DNA release reaches 97% after 400 min, corresponding to a surface density of 22 ± 4 nmol cm⁻². A competing enzymatic gate, composed of co-immobilized glucose oxidase and catalase (GOx–CAT) on magnetic nanoparticles (MNPs), enables remote suppression of electron flow and DNA release upon application of a 0.3 T magnetic field. Under “OFF” conditions, DNA release is reduced to 1%, and anodic current decreases by 60%. The system exhibits excellent reversibility over four ON–OFF cycles with minimal performance degradation. This bioelectronic platform represents a self-powered, reversible strategy for stimuli-responsive drug release.

Original language	English
Article number	2500131
Journal	Advanced NanoBiomed Research
Volume	5
Issue number	10
DOIs	https://doi.org/10.1002/anbr.202500131
Publication status	Published - Oct 2025
MoE publication type	A1 Journal article-refereed

Funding

The following funding agencies are acknowledged: NoOne—a binary sensor with a single-molecule digit to discriminate biofluids enclosing zero or at least one biomarker, ERC Stg2021, GA:101040383; Centro di Innovazione in Single-Molecule Digital Assay—“Digital Assay” from Regione Puglia DGR N. 218 of 21/02/2022; Italian network of excellence for advanced diagnosis (INNOVA), Ministero della Salute -code PNC-E3-2022-23683266 PNC-HLS-DA, CUP: C43C22001630001; Complementary National Plan PNC-I.1 “Research initiatives for innovative technologies and pathways in the health and welfare sector” D.D. 931 of 06/06/2022, DARE—DigitAl lifelong pRevEntion initiative, code PNC0000002. This work was partially supported by the European Union under the Italian National Recovery and Resilience Plan (NRRP) of NextGenerationEU, the partnership on “Telecommunications of the Future” (PE00000001 - program “RESTART,” Structural Project DREAMS), and CSGI (Centre for Colloid and Surface Science). Open access publishing facilitated by Universita degli Studi di Bari Aldo Moro, as part of the Wiley - CRUI-CARE agreement. The following funding agencies are acknowledged: NoOne—a binary sensor with a single‐molecule digit to discriminate biofluids enclosing zero or at least one biomarker, ERC Stg2021, GA:101040383; Centro di Innovazione in Single‐Molecule Digital Assay—“Digital Assay” from Regione Puglia DGR N. 218 of 21/02/2022; Italian network of excellence for advanced diagnosis (INNOVA), Ministero della Salute ‐code PNC‐E3‐2022‐23683266 PNC‐HLS‐DA, CUP: C43C22001630001; Complementary National Plan PNC‐I.1 “Research initiatives for innovative technologies and pathways in the health and welfare sector” D.D. 931 of 06/06/2022, DARE—DigitAl lifelong pRevEntion initiative, code PNC0000002. This work was partially supported by the European Union under the Italian National Recovery and Resilience Plan (NRRP) of NextGenerationEU, the partnership on “Telecommunications of the Future” (PE00000001 ‐ program “RESTART,” Structural Project DREAMS), and CSGI (Centre for Colloid and Surface Science).

Keywords

DNA releases
enzyme based electrodes
local pH changes
ON-OFF bioelectrochemical systems
oxygen reduction reactions

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10.1002/anbr.202500131Licence: CC BY

Advanced NanoBiomed Research - 2025 - Bollella - Pyrolyzed Walnut Shell‐Based Flexible Electrodes for MagneticallyFinal published version, 1.55 MBLicence: CC BY

https://urn.fi/URN:NBN:fi-fe2026021814043

Cite this

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title = "Pyrolyzed Walnut Shell-Based Flexible Electrodes for Magnetically Triggered ON/OFF DNA Release",

abstract = "A magnetically gated, enzymatically driven DNA release platform based on sustainable pyrolyzed walnut shell-derived carbon electrodes is reported. Upon glucose addition under aerobic conditions, biocatalytic oxygen reduction at the cathode induces a local pH increase, resulting in electrostatic repulsion of negatively charged 5(6)-carboxyfluorescein-labeled DNA (FAM-labeled DNA). Electrochemical analysis reveals an oxygen reduction reaction (ORR) onset potential of +0.576 ± 0.003 V vs. Ag/AgCl and a maximum current of −8.2 ± 0.4 μA. Electrochemical impedance spectroscopy (EIS) confirms a post-ORR increase in interfacial resistance from 6.2 ± 0.5 to 11.1 ± 0.9 kΩ. DNA release reaches 97\% after 400 min, corresponding to a surface density of 22 ± 4 nmol cm−2. A competing enzymatic gate, composed of co-immobilized glucose oxidase and catalase (GOx–CAT) on magnetic nanoparticles (MNPs), enables remote suppression of electron flow and DNA release upon application of a 0.3 T magnetic field. Under “OFF” conditions, DNA release is reduced to 1\%, and anodic current decreases by 60\%. The system exhibits excellent reversibility over four ON–OFF cycles with minimal performance degradation. This bioelectronic platform represents a self-powered, reversible strategy for stimuli-responsive drug release.",

keywords = "DNA releases, enzyme based electrodes, local pH changes, ON-OFF bioelectrochemical systems, oxygen reduction reactions",

author = "Paolo Bollella and Blanca Cassano and Verdiana Marchian{\`o} and Angelo Tricase and Eleonora Macchia and Luisa Torsi",

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AU - Bollella, Paolo

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AU - Marchianò, Verdiana

AU - Tricase, Angelo

AU - Macchia, Eleonora

AU - Torsi, Luisa

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N2 - A magnetically gated, enzymatically driven DNA release platform based on sustainable pyrolyzed walnut shell-derived carbon electrodes is reported. Upon glucose addition under aerobic conditions, biocatalytic oxygen reduction at the cathode induces a local pH increase, resulting in electrostatic repulsion of negatively charged 5(6)-carboxyfluorescein-labeled DNA (FAM-labeled DNA). Electrochemical analysis reveals an oxygen reduction reaction (ORR) onset potential of +0.576 ± 0.003 V vs. Ag/AgCl and a maximum current of −8.2 ± 0.4 μA. Electrochemical impedance spectroscopy (EIS) confirms a post-ORR increase in interfacial resistance from 6.2 ± 0.5 to 11.1 ± 0.9 kΩ. DNA release reaches 97% after 400 min, corresponding to a surface density of 22 ± 4 nmol cm−2. A competing enzymatic gate, composed of co-immobilized glucose oxidase and catalase (GOx–CAT) on magnetic nanoparticles (MNPs), enables remote suppression of electron flow and DNA release upon application of a 0.3 T magnetic field. Under “OFF” conditions, DNA release is reduced to 1%, and anodic current decreases by 60%. The system exhibits excellent reversibility over four ON–OFF cycles with minimal performance degradation. This bioelectronic platform represents a self-powered, reversible strategy for stimuli-responsive drug release.

AB - A magnetically gated, enzymatically driven DNA release platform based on sustainable pyrolyzed walnut shell-derived carbon electrodes is reported. Upon glucose addition under aerobic conditions, biocatalytic oxygen reduction at the cathode induces a local pH increase, resulting in electrostatic repulsion of negatively charged 5(6)-carboxyfluorescein-labeled DNA (FAM-labeled DNA). Electrochemical analysis reveals an oxygen reduction reaction (ORR) onset potential of +0.576 ± 0.003 V vs. Ag/AgCl and a maximum current of −8.2 ± 0.4 μA. Electrochemical impedance spectroscopy (EIS) confirms a post-ORR increase in interfacial resistance from 6.2 ± 0.5 to 11.1 ± 0.9 kΩ. DNA release reaches 97% after 400 min, corresponding to a surface density of 22 ± 4 nmol cm−2. A competing enzymatic gate, composed of co-immobilized glucose oxidase and catalase (GOx–CAT) on magnetic nanoparticles (MNPs), enables remote suppression of electron flow and DNA release upon application of a 0.3 T magnetic field. Under “OFF” conditions, DNA release is reduced to 1%, and anodic current decreases by 60%. The system exhibits excellent reversibility over four ON–OFF cycles with minimal performance degradation. This bioelectronic platform represents a self-powered, reversible strategy for stimuli-responsive drug release.

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Pyrolyzed Walnut Shell-Based Flexible Electrodes for Magnetically Triggered ON/OFF DNA Release

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