Modifying surface charge density of thermoplastic nanofluidic biosensors by multivalent cations within the slip plane of the electric double layer

Thermoplastic nanofluidic devices are promising platforms for sensing single biomolecules due to their mass fabrication capability. When the molecules are driven electrokinetically through nanofluidic networks, surface charges play a significant role in the molecular capture and transportation, especially when the thickness of the electrical double layer is close to the dimensions of the nanostructures in the device. Here, we used multivalent cations to alter the surface charge density of thermoplastic nanofluidic devices. The surface charge alteration was done by filling the device with a multivalent ionic solution, followed by withdrawal of the solution and replacing it with KCl for conductance measurement. A systematic study was performed using ionic solutions containing Mg2+ and Al3+ for nanochannels made of three polymers: poly(ethylene glycol) diacrylate (PEGDA), poly(methyl methacrylate) (PMMA) and cyclic olefin copolymer (COC). Overall, multivalent cations within the slip plane decreased the effective surface charge density of the device surface and the reduction rate increased with the cation valency, cation concentration and the surface charge density of thermoplastic substrates. We demonstrated that a 10-nm diameter in-plane nanopore formed in COC allowed translocation of λ-DNA molecules after Al3+ modification, which is attributed to the deceased viscous drag force in the nanopore by the decreased surface charge density. This work provides a general method to manipulate surface charge density of nanofluidic devices for biomolecule resistive pulse sensing. Additionally, the experimental results support ion-ion correlations as the origin of charge inversion over specific chemical adsorption.

Medienart:

E-Artikel

Erscheinungsjahr:

2022

Erschienen:

2022

Enthalten in:

Zur Gesamtaufnahme - volume:648

Enthalten in:

Colloids and surfaces. A, Physicochemical and engineering aspects - 648(2022) vom: 05. Sept.

Sprache:

Englisch

Beteiligte Personen:

Jia, Zheng [VerfasserIn]
Choi, Junseo [VerfasserIn]
Lee, Sunggun [VerfasserIn]
Soper, Steven A [VerfasserIn]
Park, Sunggook [VerfasserIn]

Links:

Volltext

Themen:

Biomolecule sensing
Charge inversion
DNA translocation
Journal Article
Multivalent ions
Nanopore
Thermoplastic nanofluidics

Anmerkungen:

Date Revised 02.02.2023

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1016/j.colsurfa.2022.129147

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM351964924