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Hsu MC, Alfadhel A, Forouzandeh F, Borkholder D. Biocompatible Magnetic Nanocomposite Microcapsules as Microfluidic One-way Diffusion Blocking Valves with Ultra-low Opening Pressure. MATERIALS & DESIGN 2018; 150:86-93. [PMID: 30364560 PMCID: PMC6197471 DOI: 10.1016/j.matdes.2018.04.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A one-of-a-kind biocompatible magnetic nanocomposite microcapsule is developed as an in-line passive valve that can be integrated with micropumps and microfluidics. The magnetic nanocomposites act as the core for building a valve that utilizes the magnetic force attraction for sealing the microfluidic channels. The nanocomposites, molded with commercial microtubings, are prepared by incorporating Fe3O4 nanoparticles into polyethylene-glycol (PEG). Parylene-C provides a flexible, biocompatible shell and moisture barrier for the microcapsule that enables deformation and sealing to the microfluidic channel wall. The highly customizable valve design offers easy scalability, and simplicity for integration into microfluidic systems. The presented magnetically-responsive microcapsule demonstrates reliable performance as a passive one-way valve that exhibits unique features and capabilities including effective flow-rectification with steady flows, extremely low leakage flows from backpressures at a rate of 4.7 nL/min kPa-1, successfully block 99.96% of the diffusion, and extremely low inlet flow opening pressure of 2.1 kPa.
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Affiliation(s)
- Meng-Chun Hsu
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Ahmed Alfadhel
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Farzad Forouzandeh
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - David Borkholder
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY, USA
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Alfadhel A, Ouyang J, Mahajan CG, Forouzandeh F, Cormier D, Borkholder DA. Inkjet Printed Polyethylene Glycol as a Fugitive Ink for the Fabrication of Flexible Microfluidic Systems. MATERIALS & DESIGN 2018; 150:182-187. [PMID: 30364619 PMCID: PMC6197481 DOI: 10.1016/j.matdes.2018.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper demonstrates a novel and simple processing technique for the realization of scalable and flexible microfluidic microsystems by inkjet-printing polyethylene-glycol (PEG) as a sacrificial template, followed by embedding in a structural layer (e.g. soft elastomers). The printing technology allows production of an array of PEG droplets simultaneously, reducing cost and manufacturing time. The PEG can be removed through heating above its phase-change temperature after the formation of the structural layer, with hydraulic flow removing the material. The developed technique allows easy modulation of the shape and dimensions of the pattern with the ability to generate complex architectures without using lithography. The method produces robust planar and multilayer microfluidic structures that can be realized on wide range of substrates. Moreover, microfluidics can be realized on other systems (e.g. electrodes and transducers) directly without requiring any bonding or assembling steps, which often limit the materials selection in conventional microfluidic fabrication. Multilayer Polydimethylsiloxane (PDMS) microfluidic channels were created using this technique to demonstrate the capability of the concept to realize flexible microfluidic electronics, drug delivery systems, and lab-on-a-chip devices. By utilizing conductive liquid metals (i.e. EGaIn) as the filling material of the channels, flexible passive resistive components and sensors have been realized.
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Affiliation(s)
- Ahmed Alfadhel
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Jing Ouyang
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Chaitanya G. Mahajan
- Industrial and Systems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Farzad Forouzandeh
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Denis Cormier
- Industrial and Systems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - David A. Borkholder
- Microsystems Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
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Frisina RD, Ding B, Zhu X, Walton JP. Age-related hearing loss: prevention of threshold declines, cell loss and apoptosis in spiral ganglion neurons. Aging (Albany NY) 2017; 8:2081-2099. [PMID: 27667674 PMCID: PMC5076453 DOI: 10.18632/aging.101045] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/08/2016] [Indexed: 12/18/2022]
Abstract
Age-related hearing loss (ARHL) -presbycusis - is the most prevalent neurodegenerative disease and number one communication disorder of our aged population; and affects hundreds of millions of people worldwide. Its prevalence is close to that of cardiovascular disease and arthritis, and can be a precursor to dementia. The auditory perceptual dysfunction is well understood, but knowledge of the biological bases of ARHL is still somewhat lacking. Surprisingly, there are no FDA-approved drugs for treatment. Based on our previous studies of human subjects, where we discovered relations between serum aldosterone levels and the severity of ARHL, we treated middle age mice with aldosterone, which normally declines with age in all mammals. We found that hearing thresholds and suprathreshold responses significantly improved in the aldosterone-treated mice compared to the non-treatment group. In terms of cellular and molecular mechanisms underlying this therapeutic effect, additional experiments revealed that spiral ganglion cell survival was significantly improved, mineralocorticoid receptors were upregulated via post-translational protein modifications, and age-related intrinsic and extrinsic apoptotic pathways were blocked by the aldosterone therapy. Taken together, these novel findings pave the way for translational drug development towards the first medication to prevent the progression of ARHL.
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Affiliation(s)
- Robert D Frisina
- Department Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA.,Department Chemical and Biomedical Engineering, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
| | - Bo Ding
- Department Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
| | - Xiaoxia Zhu
- Department Chemical and Biomedical Engineering, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
| | - Joseph P Walton
- Department Communication Sciences and Disorders, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA.,Department Chemical and Biomedical Engineering, Global Center for Hearing and Speech Research, University of South Florida, Tampa FL, 33612, USA
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Johnson DG, Borkholder DA. Towards an Implantable, Low Flow Micropump That Uses No Power in the Blocked-Flow State. MICROMACHINES 2016; 7:E99. [PMID: 30404274 PMCID: PMC6189832 DOI: 10.3390/mi7060099] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/26/2016] [Accepted: 05/20/2016] [Indexed: 11/25/2022]
Abstract
Low flow rate micropumps play an increasingly important role in drug therapy research. Infusions to small biological structures and lab-on-a-chip applications require ultra-low flow rates and will benefit from the ability to expend no power in the blocked-flow state. Here we present a planar micropump based on gallium phase-change actuation that leverages expansion during solidification to occlude the flow channel in the off-power state. The presented four chamber peristaltic micropump was fabricated with a combination of Micro Electro Mechanical System (MEMS) techniques and additive manufacturing direct write technologies. The device is 7 mm × 13 mm × 1 mm (<100 mm³) with the flow channel and exterior coated with biocompatible Parylene-C, critical for implantable applications. Controllable pump rates from 18 to 104 nL/min were demonstrated, with 11.1 ± 0.35 nL pumped per actuation at an efficiency of 11 mJ/nL. The normally-closed state of the gallium actuator prevents flow and diffusion between the pump and the biological system or lab-on-a-chip, without consuming power. This is especially important for implanted applications with periodic drug delivery regimens.
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Affiliation(s)
- Dean G Johnson
- Rochester Institute of Technology, Microsystems Engineering, Rochester, NY 14623, USA.
| | - David A Borkholder
- Rochester Institute of Technology, Microsystems Engineering, Rochester, NY 14623, USA.
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Kim ES, Gustenhoven E, Mescher MJ, Pararas EEL, Smith KA, Spencer AJ, Tandon V, Borenstein JT, Fiering J. A microfluidic reciprocating intracochlear drug delivery system with reservoir and active dose control. LAB ON A CHIP 2014; 14:710-21. [PMID: 24302432 PMCID: PMC3902088 DOI: 10.1039/c3lc51105g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Reciprocating microfluidic drug delivery, as compared to steady or pulsed infusion, has unique features which may be advantageous in many therapeutic applications. We have previously described a device, designed for wearable use in small animal models, that periodically infuses and then withdraws a sub-microliter volume of drug solution to and from the endogenous fluid of the inner ear. This delivery approach results in zero net volume of liquid transfer while enabling mass transport of compounds to the cochlea by means of diffusion and mixing. We report here on an advanced wearable delivery system aimed at further miniaturization and complex dosing protocols. Enhancements to the system include the incorporation of a planar micropump to generate reciprocating flow and a novel drug reservoir that maintains zero net volume delivery and permits programmable modulation of the drug concentration in the infused bolus. The reciprocating pump is fabricated from laminated polymer films and employs a miniature electromagnetic actuator to meet the size and weight requirements of a head-mounted in vivo guinea pig testing system. The reservoir comprises a long microchannel in series with a micropump, connected in parallel with the reciprocating flow network. We characterized in vitro the response and repeatability of the planar pump and compared the results with a lumped element simulation. We also characterized the performance of the reservoir, including repeatability of dosing and range of dose modulation. Acute in vivo experiments were performed in which the reciprocating pump was used to deliver a test compound to the cochlea of anesthetized guinea pigs to evaluate short-term safety and efficacy of the system. These advances are key steps toward realization of an implantable device for long-term therapeutic applications in humans.
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Affiliation(s)
- Ernest S Kim
- The Charles Stark Draper Laboratory, Cambridge, MA, USA.
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Borkholder DA, Zhu X, Frisina RD. Round window membrane intracochlear drug delivery enhanced by induced advection. J Control Release 2013; 174:171-6. [PMID: 24291333 DOI: 10.1016/j.jconrel.2013.11.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 11/22/2013] [Indexed: 11/24/2022]
Abstract
Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy+canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds.
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Affiliation(s)
- David A Borkholder
- Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester 14623, USA; Department of Microsystems Engineering, Rochester Institute of Technology, Rochester 14623, USA; Department of Otolaryngology, University of Rochester Medical School, Rochester 14642, USA; Department of Biomedical Engineering, University of Rochester Medical School, Rochester 14642, USA.
| | - Xiaoxia Zhu
- Department of Otolaryngology, University of Rochester Medical School, Rochester 14642, USA; International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester 14623, USA.
| | - Robert D Frisina
- Department of Otolaryngology, University of Rochester Medical School, Rochester 14642, USA; Department of Biomedical Engineering, University of Rochester Medical School, Rochester 14642, USA; Department of Neurobiology & Anatomy, University of Rochester Medical School, Rochester 14642, USA; International Center for Hearing & Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester 14623, USA.
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Pararas EEL, Borkholder DA, Borenstein JT. Microsystems technologies for drug delivery to the inner ear. Adv Drug Deliv Rev 2012; 64:1650-60. [PMID: 22386561 DOI: 10.1016/j.addr.2012.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 02/06/2012] [Accepted: 02/15/2012] [Indexed: 12/20/2022]
Abstract
The inner ear represents one of the most technologically challenging targets for local drug delivery, but its clinical significance is rapidly increasing. The prevalence of sensorineural hearing loss and other auditory diseases, along with balance disorders and tinnitus, has spurred broad efforts to develop therapeutic compounds and regenerative approaches to treat these conditions, necessitating advances in systems capable of targeted and sustained drug delivery. The delicate nature of hearing structures combined with the relative inaccessibility of the cochlea by means of conventional delivery routes together necessitate significant advancements in both the precision and miniaturization of delivery systems, and the nature of the molecular and cellular targets for these therapies suggests that multiple compounds may need to be delivered in a time-sequenced fashion over an extended duration. Here we address the various approaches being developed for inner ear drug delivery, including micropump-based devices, reciprocating systems, and cochlear prosthesis-mediated delivery, concluding with an analysis of emerging challenges and opportunities for the first generation of technologies suitable for human clinical use. These developments represent exciting advances that have the potential to repair and regenerate hearing structures in millions of patients for whom no currently available medical treatments exist, a situation that requires them to function with electronic hearing augmentation devices or to live with severely impaired auditory function. These advances also have the potential for broader clinical applications that share similar requirements and challenges with the inner ear, such as drug delivery to the central nervous system.
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Affiliation(s)
- Erin E Leary Pararas
- Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139, USA
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