Supercapacitive transport of pharmacologic agents using nanoporous gold electrodes

Gittard, Shaun D.; Pierson, Bonnie E.; Ha, Cindy M.; Wu, Chung-An Max; Narayan, Roger J.; Robinson, David B.

doi:10.1002/biot.200900250

Cited by 25 publications

(18 citation statements)

References 57 publications

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“…It should be noted that the loading capacity for the SAM-modified np-Au also decreased, as the SAM layer likely reduced the fluorescein-surface affinity. With the availability of a large repertoire of functional thiols 60,61 and the ability to iontophoretically load np-Au films 62 , it should be possible to optimize the system to circumvent the reduced loading capacity and also to modulate the sensitivity to halides or molecular triggers for tuning the release rate. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 mechanism played a more dominant role at higher ionic strengths, while the latter proved to be more important at lower ionic strengths.…”

Section: Modulating Sensitivity Of Release To Halidesmentioning

confidence: 99%

Halide-Gated Molecular Release from Nanoporous Gold Thin Films

Polat

Şeker

2015

J. Phys. Chem. C

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Nanoporous materials have attracted significant attention as drug delivery platforms, in which interfacial phenomena are often more influential than fluid mechanics in defining molecular loading capacity and release kinetics. This study employs nanoporous gold (np-Au) as a model material system to investigate physical mechanisms of molecular release of fluorescein (a small molecule drug surrogate) from the sub-micron-thick np-Au coatings. Specifically, the study reveals an interfacial mechanism where halide ion-gold surface interactions dictate the loading capacity and release kinetics of fluorescein. We systematically study the effect of halide concentration and species on release kinetics from sputter-deposited np-Au films with a combination of quantitative electron microscopy, fluorospectrometry, and electrochemical surface characterization techniques. The results suggest that the interplay of halide-gold interaction probability and affinity determine the nature of release kinetics. The former mechanism plays a more dominant role at higher ionic strengths, while the latter is more important at lower ionic strengths. This interfacial phenomenon is further complemented by functionalizing the np-Au with self-assembled monolayers (SAMs) of alkane-thiols for modulating gold surface-halide affinity and consequently the molecular release kinetics.

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Section: Modulating Sensitivity Of Release To Halidesmentioning

confidence: 99%

Halide-Gated Molecular Release from Nanoporous Gold Thin Films

Polat

Şeker

2015

J. Phys. Chem. C

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“…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%

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

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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“…Their open-cell porous nanostructure makes them promising candidates for applications including catalysis [1-7] and sensing [8,9]. They also show potential as actuators [10][11][12][13][14] for micro-electro-mechanical systems and drug delivery devices [15]. Nanoporous gold (np-Au) has been the focus of many studies, due to the relatively simple method of synthesis via chemical dealloying from gold-silver alloys [16].…”

mentioning

confidence: 99%

Mechanical properties of bulk single crystalline nanoporous gold investigated by millimetre-scale tension and compression testing

Briot

Kennerknecht

Eberl

et al. 2014

Philosophical Magazine

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In this work, the mechanical behaviour of millimetre-scale, bulk single crystalline, nanoporous gold at room temperature is reported for the first time. Tension and compression tests were performed with a custom-designed test system that accommodates small-scale samples. The absence of grain boundaries in the specimens allowed measurement of the inherent strength of millimetre-scale nanoporous gold in tension. The elastic modulus and strength values in tension and compression were found to be significantly lower than values measured with nanoindentation-based techniques and previously reported in the literature, but close to those reported for millimetre-scale polycrystalline samples tested using traditional compression techniques. Fracture toughness was found to be very low, in agreement with the macroscopic brittleness of nanoporous gold, but this is due to the localization of deformation to a narrow zone of ligaments, which individually exhibit significant plasticity and necking

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Supercapacitive transport of pharmacologic agents using nanoporous gold electrodes

Cited by 25 publications

References 57 publications

Halide-Gated Molecular Release from Nanoporous Gold Thin Films

Halide-Gated Molecular Release from Nanoporous Gold Thin Films

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

Mechanical properties of bulk single crystalline nanoporous gold investigated by millimetre-scale tension and compression testing

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