scholarly journals Ultra-compliant carbon nanotube stretchable direct bladder interface

2019 ◽  
Author(s):  
Dongxiao Yan ◽  
Tim M. Bruns ◽  
Yuting Wu ◽  
Lauren L. Zimmerman ◽  
Chris Stephan ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Large Strain ◽  
Composite Electrodes ◽  
Organ Function ◽  
In Vivo Measurement ◽  
Sensor Resistance ◽  
Bladder Contraction ◽  
Electrical Stimulator

AbstractThe bladder, stomach, intestines, heart, and lungs all move dynamically to achieve their purpose. A long-term implantable device that can attach onto an organ, sense its movement, and deliver current to modify the organ function would be useful in many therapeutic applications. The bladder, for example, is a smooth muscle organ that can suffer from incomplete contractions that result in urinary retention with patients requiring using catheterization. Those affected may benefit from a combination of strain sensor and electrical stimulator to better control bladder emptying. We describe the materials and design of such a device made from thin layer carbon nanotube (CNT) and Ecoflex 00-50 and demonstrate its function with in vivo feline bladders. During bench-top characterization, the resistive and capacitive sensors exhibited reliable output throughout 5,000 stretching cycles under physiology condition. In vivo measurement with piezoresistive device showed a high correlation between sensor resistance and volume. Stimulation driven from Pt-PDMS composite electrodes successfully induced bladder contraction. We present method for reliable connection and packaging of medical grade wire to the CNT device. This work is an important step toward the translation of low-durometer elastomers, stretchable CNT percolation and Pt-PDMS composite, which are ideal for large strain bioelectric applications to sense or modulate dynamic organ states.

Real Time In Vivo Measurement of Ascorbate in the Brain Using Carbon Nanotube-Modified Microelectrodes

2013 ◽  
Vol 25 (7) ◽  
pp. 1757-1763 ◽  
Author(s):  
Nuno R. Ferreira ◽  
Ricardo M. Santos ◽  
João Laranjinha ◽  
Rui M. Barbosa
Keyword(s):  
Carbon Nanotube ◽  
Real Time ◽  
In Vivo Measurement ◽  
The Brain

In vivo measurement of microvasculature: A method for repeated and reproducible quantitation during long-term experiments

1979 ◽  
Vol 18 (1) ◽  
pp. 18-32 ◽  
Author(s):  
G.S. Dimitrievich ◽  
K. Fischer-Dzoga ◽  
R.M. Lee ◽  
M.L. Griem
Keyword(s):  
In Vivo Measurement ◽  
Long Term Experiments

scholarly journals Friction and Wear Behaviors of Reduced Graphene Oxide- and Carbon Nanotube-Reinforced Hydroxyapatite Bioceramics

2020 ◽  
Vol 7 ◽  
Author(s):  
Huanlong Hu ◽  
Zhong Li ◽  
Wen Sun ◽  
Ruitao Li ◽  
Hua Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Carbon Nanotube ◽  
Reduced Graphene Oxide ◽  
Friction And Wear ◽  
Solid Lubrication ◽  
Wear Properties ◽  
Reduced Graphene ◽  
Friction And Wear Properties

Friction and wear properties play an important role in the long-term in vivo performance of load-bearing bioceramic implants. In this study, the friction and wear behaviors of hydroxyapatite (HA) reinforced with reduced graphene oxide (rGO) and rGO + carbon nanotube (CNT) hybrids were studied by ball-on-disk tests to understand the effects of nanocarbon content and morphology on the composites’ tribological behaviors. The intact and worn surfaces were characterized by optical microscopy, nanoindentation, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. We found that the incorporation of rGO and rGO + CNT hybrids in HA bioceramic both improved the friction and wear behaviors, and the highest wear resistance was achieved by employing 1 wt% rGO and 1 wt% CNT as reinforcements. The major reinforcing mechanism was the formation of carbonaceous films between the composite surfaces and counterbody, which served as solid lubrication films that resulted in a lower coefficient of friction, higher hardness, and increased hardness/modulus ratio. Importantly, CNT addition facilitated the uniform distribution of the reinforcements in the HA matrix and the pinning effects of CNT enhanced the connection between rGO and HA.

scholarly journals Long-Term In Vivo Biocompatibility of Single-Walled Carbon Nanotubes

2019 ◽  
Author(s):  
Thomas V. Galassi ◽  
Merav Antman-Passig ◽  
Zvi Yaari ◽  
Jose Jessurun ◽  
Robert E. Schwartz ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Near Infrared ◽  
Complete Blood Count ◽  
Aggregation State ◽  
Single Walled Carbon ◽  
Wide Range ◽  
Short And Long Term

AbstractOver the past two decades, measurements of carbon nanotube toxicity and biodistribution have yielded a wide range of results. Properties such as nanotube type (single-walled vs. multi-walled), purity, length, aggregation state, and functionalization, as well as route of administration, greatly affect both the biocompatibility and biodistribution of carbon nanotubes. These differences suggest that generalizable conclusions may be elusive and that studies must be material- and application-specific. Here, we assess the short- and long-term biodistribution and biocompatibility of a single-chirality DNA-encapsulated single-walled carbon nanotube complex upon intravenous administration that was previously shown to function as an in-vivo reporter of endolysosomal lipid accumulation. Regarding biodistribution and fate, we found bulk specificity to the liver and >90% signal attenuation by 14 days in mice. Using near-infrared hyperspectral microscopy to measure single nanotubes, we found low-level, long-term persistence in organs such as the heart, liver, lung, kidney, and spleen. Measurements of histology, animal weight, complete blood count, and biomarkers of organ function all suggest short- and long-term biocompatibility. This work suggests that carbon nanotubes can be used as preclinical research tools in-vivo without affecting acute or long-term health.

In vivo measurement of structural changes in the microcirculation of the skeletal muscle under long term blood flow loading

Biorheology ◽  
1996 ◽  
Vol 33 (1) ◽  
pp. 84-84
Author(s):  
K KOSAKI ◽  
S ICHIOKA ◽  
M SHIBATA ◽  
A KAWARADA ◽  
A KAMIYA
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Structural Changes ◽  
In Vivo Measurement

Long term in vivo reactions to PTFE and polyester in the cardiovascular system - what will be the fate of septal defect occlusion devices?

2014 ◽  
Vol 62 (S 01) ◽  
Author(s):  
M. Sigler ◽  
S. Huell ◽  
R. Foth ◽  
W. Ruschewski ◽  
T. Tirilomis ◽  
...  
Keyword(s):  
Cardiovascular System ◽  
Septal Defect

The depressing (negative) effect of oestradiol benzoate on the in vitro secretion of LH and FSH by the pituitary gland of the LRH-pretreated long-term ovariectomized rat changes into the augmentative (positive) effect after discontinuation of the LRH-pretreatment

1985 ◽  
Vol 110 (3) ◽  
pp. 329-337 ◽  
Author(s):  
G. A. Schuiling ◽  
H. Moes ◽  
T. R. Koiter
Keyword(s):  
Depressing Effect ◽  
Ovx Rats ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate ◽  
Negative Effect ◽  
Positive Effect ◽  
Perifusion System

Abstract. The effect of pretreatment in vivo with oestradiol benzoate on in vitro secretion of LH and FSH was studied in long-term ovariectomized (OVX) rats both at the end of a 5-day continuous in vivo pretreatment with LRH and 4-days after cessation of such LRH pretreatment. Rats were on day 0 sc implanted with osmotic minipumps which released LRH at the rate of 250 ng/h. Control rats were implanted with a piece of silicone elastomer with the dimensions of a minipump. On days 2 and 4 the rats were injected with either 3 μg EB or with oil. On day 5 part of the rats were decapitated and the in vitro autonomous (i.e. non-LRH-stimulated) and 'supra-maximally' LRHstimulated release of LH and FSH was studied using a perifusion system. From other rats the minipumps were removed on day 5 and perifusion was performed on day 9. On the 5th day of the in vivo LRH pretreatment the pituitary LH/FSH stores were partially depleted; the pituitaries of the EB-treated rats more so than those of the oil-injected rats. EB alone had no significant effect on the content of the pituitary LH- and FSH stores. On day 9, i.e. 4 days after removal of the minipumps, the pituitary LH and FSH contents had increased in both the oil- and the EB injected rats, but had not yet recovered to control values. In rats not subjected to the 5-days pretreatment with LRH EB had a positive effect on the supra-maximally LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. EB had no effect on the non-stimulated secretion of FSH. After 5 days of in vivo pretreatment with LRH only, the in vitro non-stimulated and supra-maximally LRH-stimulated secretion of both LH and FSH were strongly impaired, the effect correlating well with the LRH-induced depletion of the pituitary LH/FSH stores. In such LRH-pretreated rats EB had on day 5 a negative effect on the (already depressed) LRH-stimulated secretion of LH (not on that of FSH). EB had no effect on the non-stimulated LH/FSH secretion. It could be demonstrated that the negative effect of the combined LRH/EB pretreatment was mainly due to the depressing effect of this treatment on the pituitary LH and FSH stores: the effect of oestradiol on the pituitary LRH-responsiveness (release as related to pituitary gonadotrophin content) remained positive. In LRH-pretreated rats, however, this positive effect of EB was smaller than in rats not pretreated with LRH. Four days after removal of the minipumps there was again a positive effect of EB on the LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. The positive effect of EB on the pituitary LRH-responsiveness was as strong as in rats which had not been exposed to exogenous LRH. The non-stimulated secretion of FSH was again not affected by EB. The results demonstrate that the effect of EB on the oestrogen-sensitive components of gonadotrophin secretion consists of two components: an effect on the pituitary LRH-responsiveness proper, and an effect on the pituitary LH/FSH stores. The magnitude of the effect of EB on the LRH-responsiveness is LRH dependent: it is very weak (almost zero) in LRH-pretreated rats, but strong in rats not exposed to LRH as well as in rats of which the LRH-pretreatment was stopped 4 days previously. Similarly, the effect of EB on the pituitary LH and FSH stores is LRH-dependent: in the absence of LRH, EB has no influence on the contents of these stores, but EB can potentiate the depleting effect of LRH on the LH/FSH-stores. Also this effect disappear after cessation of the LRH-pretreatment.

Enhanced Stability and Controlled Delivery of MOF Encapsulated Vaccines and Their Immunogenic Response In Vivo

2018 ◽  
Author(s):  
Michael Luzuriaga ◽  
Raymond P. Welch ◽  
Madushani Dharmawardana ◽  
Candace Benjamin ◽  
Shaobo Li ◽  
...  
Keyword(s):  
Viral Vector ◽  
Controlled Delivery ◽  
Conformational Structure ◽  
Spectroscopy Analysis ◽  
Zeolitic Imidazolate Framework ◽  
Structural Conformation ◽  
Depth Study ◽  
Viral Nanoparticle

<div><div><div><p>Vaccines have an innate tendency to lose their structural conformation upon environmental and chemical stressors. A loss in conformation reduces the therapeutic ability to prevent the spread of a pathogen. Herein, we report an in-depth study of zeolitic imidazolate framework-8 (ZIF-8) and its ability to provide protection for a model viral vector against dena- turing conditions. The immunoassay and spectroscopy analysis together demonstrate enhanced thermal and chemical stability to the conformational structure of the encapsulated viral nanoparticle. The long-term biological activity of this virus-ZIF composite was investigated in animal models to further elucidate the integrity of the encapsulated virus, the bio-safety, and immunogenicity of the overall composite. Additionally, histological analysis found no observable tissue damage in the skin or vital organs in mice, following multiple subcutaneous administrations. This study shows that ZIF-based protein composites are strong candidates for improved preservation of proteinaceous drugs, are biocompatible, and capable of controlling the release and adsorption of drugs in vivo.</p></div></div></div>

Sign in / Sign up

Export Citation Format

Share Document