Microfabrication of Nanoporous Gold Patterns for Cell-material Interaction Studies

Daggumati, Pallavi; Kurtuluş, Özge; Dimlioglu, Damla; Şeker, Erkin

doi:10.3791/50678

Cited by 19 publications

(32 citation statements)

References 21 publications

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“…25 This and other studies ongoing in our laboratory focus on studying histological and electrophysiological cortical cell response as a function of np-Au morphology to gain insight into the mechanisms by which morphology determines cortical cell coverage and recording fidelity. The differential effects of np-Au on astrocytic versus neuronal cell coverage reported in this study, coupled with previous demonstrations of high fidelity recordings from organoypic slices, 29 compatibility with microfabrication, 28 and reduction of astrocytic proliferation via in situ drug release from the np-Au patterns, 31 identify np-Au as a promising functional coating for chronic neural interfaces.…”

Section: Discussionsupporting

confidence: 69%

“…Images of immunostained samples were acquired using an inverted fluorescent microscope (Zeiss Observer D1). Epi-fluorescent images were analyzed using a custom ImageJ macro 28 to determine cell coverage of a given surface.…”

Section: Methodsmentioning

confidence: 99%

“…25 It combines many other attractive features such as high effective surface area, 17 tunable pore size, 26 well-defined conjugate chemistry, 27 high electrical conductivity, and compatibility with traditional fabrication techniques. 28 The suitability of np-Au as a multifunctional neural electrode coating is highlighted in recent studies that demonstrate its application in high-fidelity recordings from organotypic brain slices, 29 biocompatibility, 29-31 in situ drug delivery for reducing astrocytic proliferation, 31 on demand drug release, 18, 32 and biofouling-resistant electrical performance. 33 Here we report the novel ability for np-Au to reduce astrocytic coverage through topographical cues.…”

Section: Introductionmentioning

confidence: 99%

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Nanoporous Gold as a Neural Interface Coating: Effects of Topography, Surface Chemistry, and Feature Size

Chapman¹,

Chen²,

Stamou³

et al. 2015

ACS Appl. Mater. Interfaces

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131

158

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Designing neural-electrode interfaces that maintain close physical coupling of neurons to the electrode surface remains a major challenge for both implantable and in vitro neural recording electrode arrays. Typically, low-impedance nanostructured electrode coatings rely on chemical cues from pharmaceuticals or surface-immobilized peptides to suppress glial scar tissue formation over the electrode surface (astrogliosis), which is an obstacle to reliable neuron-electrode coupling. Nanoporous gold (np-Au), produced by an alloy corrosion process, is a promising candidate to reduce astrogliosis solely through topography by taking advantage of its tunable length scale. In the present in vitro study on np-Au’s interaction with cortical neuron-glia co-cultures, we demonstrate that the nanostructure of np-Au is achieving close physical coupling of neurons through maintaining a high neuron-to-astrocyte surface coverage ratio. Atomic layer deposition-based surface modification was employed to decouple the effect of morphology from surface chemistry. Additionally, length scale effects were systematically studied by controlling the characteristic feature size of np-Au through variations of the dealloying conditions. Our results show that np-Au nanotopography, not surface chemistry, reduces astrocyte surface coverage while maintaining high neuronal coverage, and may enhance the neuron-electrode coupling through nanostructure-mediated suppression of scar tissue formation.

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Section: Discussionsupporting

confidence: 69%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nanoporous Gold as a Neural Interface Coating: Effects of Topography, Surface Chemistry, and Feature Size

Chapman¹,

Chen²,

Stamou³

et al. 2015

ACS Appl. Mater. Interfaces

Self Cite

131

158

View full text Add to dashboard Cite

show abstract

“…Sample preparation: The gold-silver alloy (precursor to np-Au) patterns were created on the glass coverslips with a combination of photolithography, sputter-deposition, and dealloying processes [31].…”

Section: Methodsmentioning

confidence: 99%

Electrically tunable pore morphology in nanoporous gold thin films

Dorofeeva

Şeker

2015

Nano Res.

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Electrical current is used for tuning pore morphology of nanoporous gold thin films at significantly lower temperatures than previously reported via electrically-assisted mechanisms.This technique allows for precisely controlling the extent and location of pore coarsening and producing a wide range of distinct morphologies on a single substrate for high-throughput studies of structure-property relationships. ABSTRACTNanoporous gold (np-Au) is an emerging nanostructured material that exhibits many desirable properties, including high electrical and thermal conductivity, high surface area-to-volume ratio, tunable pore morphology, well-established surface-binding chemistry, and compatibility with microfabrication. These features made np-Au a popular material for fuel cells, optical and electrical biosensors, drug delivery vehicles, neural electrode coatings, and as a model system for nano-scale mechanics. In each application, np-Au morphology plays an essential role in the overall device operation. Therefore, precise control of morphology is necessary for attaining optimal device performance. Traditionally, thermal treatment in furnaces and on hot plates is used for obtaining np-Au with self-similar but coarser morphologies. However, this approach lacks the ability to create different morphologies on a single substrate and requires high temperatures (>250 °C) that are not compatible with most plastic substrates. Herein, we report electro-annealing as a method that for the first time makes it possible to control the extent and location of pore coarsening on a single substrate with one fast treatment step. In addition, the electro-annealing entails much lower temperatures (<150 °C) than traditional thermal treatment, putatively due to electrically-assisted phenomena that contribute to thermally-activated surface diffusion of gold atoms responsible for coarsening. Overall, this approach can be easily scaled up to display multiple pore morphologies on a single chip and therefore enable high-throughput screening of optimal nanostructures for specific applications.

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“…3` end of p2 was modified with an amine group to enable tagging with MB. Probe ssDNA (p1): 5ThioMC6-D/CGT GTT ATA AAA TGT AAT TTG GAA TT; Probe ssDNA (p2): 5ThioMC6-D/CGT GTT ATA AAA TGT AAT TTG GAA TT/3AmMO Target DNA (t1): AAT TCC AAA TTA CAT TTT ATA ACA CG Fabrication of nanoporous gold (np-Au) electrodes Np-Au gold films were prepared as described previously 41 . Briefly, the glass coverslips were cleaned by immersion in a freshly-prepared piranha solution for 10 minutes, rinsed with deionized (DI) water, and dried under nitrogen flow prior to metal deposition.…”

Section: Experimental Section Chemicals and Reagentsmentioning

confidence: 99%

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

2015

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Advances in materials science and chemistry have led to the development of a wide range of nanostructured materials for building novel electrochemical biosensors. A systematic understanding of the challenges related to electrode morphology involved in designing such sensors is essential for developing effective biosensing tools. In this study, we use nanoporous gold (npAu) thin film electrode coatings with sub-micron thicknesses, as a model system to investigate the influence of nanostructuring on DNA-methylene blue (MB) interactions and their application for DNA biosensors. The interaction of single-and double-stranded DNA immobilized onto morphologically different np-Au films with MB was electrochemically interrogated via square wave voltammetry (SWV). The electrochemical signal from these electrodes in response to MB decayed progressively with each SWV scan. The decay rate was governed by accessibility of the electrochemically-active np-Au surface by the analyte. The optimum frequency for extracting the maximum signal via SWV was influenced by the film morphology, where the optimum frequency was lower for the nanoporous morphology with lower density of molecular access points into the porous coating. Overall, the np-Au electrodes exhibited a 10-fold enhancement in probe grafting density and approximately 10-fold higher electrochemical current upon probetarget hybridization as compared to the planar Au electrodes. The np-Au electrodes enabled sensitive detection with a dynamic range of 10 nM to 100 nM that shifts by an order of magnitude for coarsened np-Au morphology due to increased target penetration into the porous network and hence enhanced hybridization efficiency. These findings provide insight into the influence of nanostructuring on the transport mechanisms of small molecules and nucleic acids, and yield an understanding of diverse sensor performance parameters such as DNA grafting density, hybridization efficiency, sensitivity and dynamic range.

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Microfabrication of Nanoporous Gold Patterns for Cell-material Interaction Studies

Cited by 19 publications

References 21 publications

Nanoporous Gold as a Neural Interface Coating: Effects of Topography, Surface Chemistry, and Feature Size

Nanoporous Gold as a Neural Interface Coating: Effects of Topography, Surface Chemistry, and Feature Size

Electrically tunable pore morphology in nanoporous gold thin films

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

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