A wireless chemical sensor featuring iron oxide nanoparticle-embedded hydrogels

Song, Seung Hyun; Park, J. H.; Chitnis, Girish; Siegel, Ronald A.; Ziaie, Babak

doi:10.1016/j.snb.2013.12.012

Cited by 50 publications

(25 citation statements)

References 61 publications

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“…This technique has the potential for becoming a standard pharmaceutical film characterization method with significantly improved temporal efficiency as compared to current standards (e.g., Flory-Rehner swelling, which can take days [23][24][25]). Furthermore, it may be possible to reduce the response time by micro-patterning the gelatin film (as our group has shown with other hydrogel materials [26]), but this will require further characterization to develop a model/correlation between micro-patterns and standard (un-patterned) pharmaceutical film. (e) prepare a ferrogelatin disc by casting, curing, and laser-machining dry ferrogelatin, then attach it to the PET using a UV curable adhesive; (f) the structure is ready for test using a secondary read-out coil and an impedance analyzer.…”

Section: Resultsmentioning

confidence: 99%

Nanoparticle-enabled wireless monitoring and characterization of physical degradation kinetics in pharmaceutical gelatin films

Ochoa¹,

Jiang²,

Park³

et al. 2016

Sensors and Actuators A: Physical

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Degradation kinetics of pharmaceutical excipient films effect their overall performance and drug release profile. Characterizing them is traditionally labor-intensive and time-consuming, requiring spectroscopy or periodic mass measurements. Here we present an alternative rapid technique for electrically (and wirelessly) measuring the polymeric matrix swelling and material degradation in aqueous media for characterizing functional films. The film is loaded with ferromagnetic nanoparticles and used as the core of a planar coil whose resonant frequency is monitored remotely. When placed in an aqueous solution, swelling and dissolution of the film induce contrasting changes in the capacitance and inductance of the coil, respectively, allowing identification of the swelling and dissolution phases. The dissolution profile of iron oxide-loaded gelatin is compared with spectrophotometry data, further demonstrating the technique can distinguish among films with various levels of crosslinking (showing a resonant frequency difference of 116 kHz between completely noncrosslinked and fully crosslinked gelatin). The key characteristics of the film degradation kinetics can be captured within 20-30 minutes of data collection.

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Section: Resultsmentioning

confidence: 99%

Nanoparticle-enabled wireless monitoring and characterization of physical degradation kinetics in pharmaceutical gelatin films

Ochoa¹,

Jiang²,

Park³

et al. 2016

Sensors and Actuators A: Physical

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“…If it is too large, then there will be an extra “jamming” stress. Recently, a simple method to measure hydrogel swelling in a small cavity has been proposed, which avoids these difficulties [215]. In this method, commercially available SPIONs, embedded in polystyrene microspheres, are dispersed in the hydrogel during synthesis.…”

Section: Sensing and Signal Transduction By Swelling And Shrinkingmentioning

confidence: 99%

Stimuli sensitive polymers and self regulated drug delivery systems: A very partial review

Siegel

2014

Journal of Controlled Release

109

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Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an “on-demand” basis. So called “stimuli-responsive” and “intelligent” systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two.

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“…stimuli [1]- [5]. They are in particular attractive for implantable applications since they do not require an on-board power source and/or electronic circuitry.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, passive LC sensing methods require sophisticated custom-made readout electronics. We previously reported on a simpler scheme using a thin ferrogel (magnetically functionalized hydrogel) film bonded on top of a planar inductor [5]. Swelling-deswelling of the gel resulted in a change of the inductance that was remotely monitored using the standard LC sensing scheme (phase-dip method).…”

Section: Introductionmentioning

confidence: 99%

Batch-fabricated hydrogel/polymeric-magnet bilayer for wireless chemical sensing

Park¹,

Kim²,

Ziaie³

2015

2015 28th IEEE International Conference on Micro Electro Mechanical Systems (MEMS)

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This paper introduces a fabrication and wireless chemical sensing scheme using a hydrogel/ polymeric-magnet bilayer. The swelling/deswelling of the hydrogel in response to chemical stimuli (e.g. pH, glucose etc.) results in vertical movement of the polymeric permanent magnet located on top of the hydrogel film. The hydrogel volume change is wirelessly detected by a giant magnetoresistance (GMR) sensor. A pH-sensitive hydrogel magnet bilayer is fabricated and tested as proof of the concept. The sensor shows a sensitivity of 0.01 Oe/pH, a resolution of 0.05 pH unit between pH 4 and pH 6, and a response time of 30 minutes. The described device is the first integrated wireless hydrogel/polymeric-magnet transducer with potential applications in biomedical and environmental sensing areas.

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A wireless chemical sensor featuring iron oxide nanoparticle-embedded hydrogels

Cited by 50 publications

References 61 publications

Nanoparticle-enabled wireless monitoring and characterization of physical degradation kinetics in pharmaceutical gelatin films

Nanoparticle-enabled wireless monitoring and characterization of physical degradation kinetics in pharmaceutical gelatin films

Stimuli sensitive polymers and self regulated drug delivery systems: A very partial review

Batch-fabricated hydrogel/polymeric-magnet bilayer for wireless chemical sensing

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