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Di Trani N, Racca N, Demarchi D, Grattoni A. Comprehensive Analysis of Electrostatic Gating in Nanofluidic Systems. ACS APPLIED MATERIALS & INTERFACES 2022; 14:35400-35408. [PMID: 35905377 DOI: 10.1021/acsami.2c08809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular transport in nanofluidic systems exhibits properties that are unique to the nanoscale. Here, the electrostatic and steric interactions between particle and surfaces become dominant in determining particle transport. At the solid-liquid interface of charged surfaces an electric double layer (EDL) forms due to electrostatic interactions between surfaces and charged particles. In these systems, tunable charge-selective nanochannels can be generated by manipulating electrostatic gating via co-ions exclusion and counterions enrichment of the EDL at the solid-liquid interface. In this context, electrostatic gating has been used to modulate the selectivity of nanofluidic membranes for drug delivery, nanofluidic transistors, and FlowFET, among other applications. While an extensive body of literature investigating nanofluidic systems exists, there is a lack of a comprehensive analysis accounting for all major parameters involved in these systems. Here we performed an all-encompassing modeling investigation corroborated by experimental analysis to assess the influence of nanochannel size, electrolyte properties, surface chemistry, gate voltage, dielectric properties, and molecular charge and size on the exclusion and enrichment of charged analytes in nanochannels. We found that the leakage current in electrostatic gating, often overlooked, plays a dominant role in molecular exclusion. Importantly, by independently considering all ionic species, we found that counterions compete for EDL formation at the surface proximity, resulting in concentration distributions that are nearly impossible to predict with analytical models. Achieving a deeper understanding of these nanofluidic phenomena will help the development of innovative miniaturized systems for both medical and industrial applications.
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Affiliation(s)
- Nicola Di Trani
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
| | - Nevio Racca
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy
| | - Danilo Demarchi
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy
| | - Alessandro Grattoni
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Department of Surgery, Houston Methodist Research Institute, Houston, Texas 77030, United States
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, Texas 77030, United States
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Shin SJ, Chung TD. Electrochemistry of the Silicon Oxide Dielectric Layer: Principles, Electrochemical Reactions, and Perspectives. Chem Asian J 2021; 16:3014-3025. [PMID: 34402214 DOI: 10.1002/asia.202100798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/11/2021] [Indexed: 01/26/2023]
Abstract
Electrochemistry of the silicon oxide dielectric layer, a notable insulator often used as a gate oxide, is counterintuitive, but addresses fundamental questions to yield novel scientific discoveries. In this minireview, the fundamental electron transfer mechanism of silicon oxide in the electrolyte solution is elucidated. The possible electrochemical reactions to date are discussed in detail, providing numerous potential areas of application which are elaborated and justified. This minireview not only provides background but also guides future research.
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Affiliation(s)
- Samuel J Shin
- Department of Chemistry, Seoul National University, Seoul, 08826, Korea
| | - Taek Dong Chung
- Department of Chemistry, Seoul National University, Seoul, 08826, Korea.,Advanced Institutes of Convergence Technology, Suwon-si, Gyeonggi-do, 16229, Korea
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Di Trani N, Silvestri A, Sizovs A, Wang Y, Erm DR, Demarchi D, Liu X, Grattoni A. Electrostatically gated nanofluidic membrane for ultra-low power controlled drug delivery. LAB ON A CHIP 2020; 20:1562-1576. [PMID: 32249279 PMCID: PMC7249613 DOI: 10.1039/d0lc00121j] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Patient-centered therapeutic management for chronic medical conditions is a desired but unmet need, largely attributable to the lack of adequate technologies for tailored drug administration. While triggered devices that control the delivery of therapeutics exist, they often rely on impractical continuous external activation. As such, next generation continuously tunable drug delivery systems independent of sustained external activation remain an elusive goal. Here we present the development and demonstration of a silicon carbide (SiC)-coated nanofluidic membrane that achieves reproducible and tunable control of drug release via electrostatic gating. By applying a low-intensity voltage to a buried electrode, we showed repeatable and reproducible in vitro release modulation of three model analytes. A small fluorophore (Alexa Fluor 647), a large polymer poly(sodium 4-styrenesulfonate) and a medically relevant agent (DNA), were selected as representatives of small molecule therapeutics, polymeric drug carriers, and biological therapeutics, respectively. Unlike other drug delivery systems, our technology performed consistently over numerous cycles of voltage modulation, for over 11 days. Importantly, low power consumption and minimal leakage currents were achieved during the study. Further, the SiC coating maintained integrity and chemical inertness, shielding the membrane from degradation under simulated physiological and accelerated conditions for over 4 months. Through leveraging the flexibility offered by electrostatic gating control, our technology provides a valuable strategy for tunable delivery, setting the foundation for the next generation of drug delivery systems.
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Affiliation(s)
- Nicola Di Trani
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA. and University of Chinese Academy of Science (UCAS), Shijingshan, 19 Yuquan Road, Beijing 100049, China
| | - Antonia Silvestri
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA. and Department of Electronics and Telecommunications, Polytechnic of Turin, Turin, Italy
| | - Antons Sizovs
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA.
| | - Yu Wang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA.
| | - Donald R Erm
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA.
| | - Danilo Demarchi
- Department of Electronics and Telecommunications, Polytechnic of Turin, Turin, Italy
| | - Xuewu Liu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA.
| | - Alessandro Grattoni
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, USA. and Department of Surgery, Houston Methodist Hospital, Houston, TX, USA and Department of Radiation Oncology, Houston Methodist Hospital, Houston, TX, USA
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