Surface Modification of Polyimide Thin Films for Peripheral Invasive Neural Interfaces

2013 ◽  
Vol 7 (2) ◽  
Author(s):  
M. Righi ◽  
S. Bossi ◽  
GL. Puleo ◽  
G. Giudetti ◽  
P. Wieringa ◽  
...  
Keyword(s):  
Thin Films ◽  
Amino Acids ◽  
Surface Roughness ◽  
Neuronal Migration ◽  
Neural Interfaces ◽  
Toxic Materials ◽  
Novel Approach ◽  
Physiological Reactions

Despite recognized as one key component for establishing a functional electrical connection with nerves, neural invasive peripheral interfaces are still not optimal for long-term applications in humans. An improvement in the field of biocompatible and non-toxic materials is necessary to overcome the issues of interface/tissue mismatch and physiological reactions. The present work aimed to study, implement and characterize a novel approach to modify the surface of neural mi-crolectrodes basedon polyimide thin films. The purpose was to improve biocompatibility and to promote neuronal migration, growth and differentiation by increasing the surface roughness and endowing the surface with structure-reactivity for thiol-containing amino acids or peptides. L-Cysteine-Rhodamine B, used as a model biomolecule, was successfully grafted on samples surface via the introduction of cross-linkable vinyl groups on polyimide foils. Preliminary in vitro biological analysis allowed to evaluate the tendency of PC12 cells to adhere and to proliferate.

Amino Acid Transporter X Is Required for Hematopoietic Stem Cell Maintenance through Regulating Specific Amino Acids Level

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1166-1166 ◽  
Author(s):  
Zhenrui Li ◽  
Keiyo Takubo ◽  
Pengxu Qian ◽  
Toshio Suda ◽  
Linheng Li
Keyword(s):  
Amino Acids ◽  
Stem Cell ◽  
Amino Acid ◽  
Acid Metabolism ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
Stem Cell Pool

Abstract Hematopoietic stem cells (HSCs) maintenance is required to preserve stem cell pool and compensate the dynamic loss of blood cells. Previous studies of HSCs maintenance mainly focus on the quiescent versus active state of HSCs and accumulated evidence indicates that metabolism plays a critical role in coordinating divergent stem cell states. While recent reports largely emphasized the role of catabolic glycolysis on long-term (LT) HSC maintenance, we found that free amino acids are enriched in primitive stem cell by ~1.5 fold. Given that amino acid metabolism in HSCs is largely unknown, we first cultured bone marrow (BM) cells with individual amino acid deprived medium to study the function of individual amino acids on HSCs in vitro. Surprisingly, we found that specific amino acids, including valine, methionine and threonine (VMT), are essential for maintaining primitive HSCs, as removing them (VMT) individually from media dramatically reduced primitive HSC number by over 95%. Thus, we hypothesize that specific amino acids are critical for preserving the stem cell pool and maintaining their function. To test it, we transplanted equal number of cells cultured with complete or individual VMT deprived media into lethally irradiated recipient mice and found VMT deprivation in vitro impaired stem cell repopulation ability. We also identified the amino acid transporter X (AATX) that is specifically expressed in HSCs and maintain VMT levels within the cell. Furthermore, inhibition of AATX reduced LT-HSC (LSK CD34- Flk2-) number in vivo. BM transplantation indicated that AATX inhibition impaired stem cell long-term reconstitution ability by over 2 fold. Our studies uncovered a role of amino acid metabolism in HSC maintenance and discovered the underlying molecular mechanism related to the amino acid transport. This finding may impact clinical treatment of blood disorders including leukemia. Disclosures No relevant conflicts of interest to declare.

scholarly journals Proposing Urothelial and Muscle In Vitro Cell Models as a Novel Approach for Assessment of Long-Term Toxicity of Nanoparticles

2020 ◽  
Vol 21 (20) ◽  
pp. 7545
Author(s):  
Matej Skočaj ◽  
Maruša Bizjak ◽  
Klemen Strojan ◽  
Jasna Lojk ◽  
Mateja Erdani Kreft ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Polyacrylic Acid ◽  
In Vitro Toxicity ◽  
Continuous Exposure ◽  
Short Term ◽  
Tio2 Nps ◽  
L6 Cells ◽  
Novel Approach

Many studies evaluated the short-term in vitro toxicity of nanoparticles (NPs); however, long-term effects are still not adequately understood. Here, we investigated the potential toxic effects of biomedical (polyacrylic acid and polyethylenimine coated magnetic NPs) and two industrial (SiO2 and TiO2) NPs following different short-term and long-term exposure protocols on two physiologically different in vitro models that are able to differentiate: L6 rat skeletal muscle cell line and biomimetic normal porcine urothelial (NPU) cells. We show that L6 cells are more sensitive to NP exposure then NPU cells. Transmission electron microscopy revealed an uptake of NPs into L6 cells but not NPU cells. In L6 cells, we obtained a dose-dependent reduction in cell viability and increased reactive oxygen species (ROS) formation after 24 h. Following continuous exposure, more stable TiO2 and polyacrylic acid (PAA) NPs increased levels of nuclear factor Nrf2 mRNA, suggesting an oxidative damage-associated response. Furthermore, internalized magnetic PAA and TiO2 NPs hindered the differentiation of L6 cells. We propose the use of L6 skeletal muscle cells and NPU cells as a novel approach for assessment of the potential long-term toxicity of relevant NPs that are found in the blood and/or can be secreted into the urine.

scholarly journals Long term in vitro stability of fully integrated wireless neural interfaces based on Utah slant electrode array

2010 ◽  
Vol 96 (7) ◽  
pp. 073702 ◽  
Author(s):  
Asha Sharma ◽  
Loren Rieth ◽  
Prashant Tathireddy ◽  
Reid Harrison ◽  
Florian Solzbacher
Keyword(s):  
Electrode Array ◽  
Neural Interfaces ◽  
Fully Integrated ◽  
In Vitro Stability

scholarly journals Impact of exocrine pancreatic adaptation on in vitro protein digestibility

1993 ◽  
Vol 69 (2) ◽  
pp. 359-369 ◽  
Author(s):  
P. Valette ◽  
H. Malouin ◽  
T. Corring ◽  
L. Savoie
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Pancreatic Enzyme ◽  
Protein Digestibility ◽  
Low Molecular Weight ◽  
Rapeseed Proteins ◽  
Total Capacity ◽  
Kinetics Of

An in vitro enzymic method was used to study the kinetics of digestion of casein and rapeseed proteins. After a predigestion step with pepsin (EC 3.4.23.1), the protein substrates were submitted to a 24 h hydrolysis either with pancreatin or pancreatic juices of pigs adapted either to casein or rapeseed diets and whose enzyme activities were different. After 3, 6 and 24 h of in vitro digestion, dialysates were collected and analysed for content of nitrogen, amino acids and low-molecular-weight peptides. For a long-term hydrolysis (24 h), overall digestibility of both substrates was not affected by the composition of pancreatic enzyme mixtures. However, at the beginning of hydrolysis a significant effect of pancreatic juices was observed, i.e. individual amino acid digestibility was generally higher when casein pancreatic juice was used for hydrolysis and their relative pattern of release was modified. For both substrates the proportion of amino acids released as low-molecular-weight peptides was not affected by the enzyme mixture used and made up about two-thirds of the total digested material. It is concluded that exocrine pancreatic adaptation to protein sources does not affect the total capacity of protein digestion. However, the changes in initial kinetics of release of amino acids are more dependent on the nature of the protein tested than on the composition of pancreatic enzyme mixtures.

scholarly journals Amino acids metabolism and degradation is regulated during porcine oviductal epithelial cells (OECs) primary culture in vitro – a signaling pathways activation approach

2018 ◽  
Vol 6 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Wiesława Kranc ◽  
Maurycy Jankowski ◽  
Joanna Budna ◽  
Piotr Celichowski ◽  
Ronza Khozmi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Epithelial Cells ◽  
Signaling Pathways ◽  
Primary Cultures ◽  
Reproduction Process ◽  
Porcine Gene ◽  
First Time ◽  
Time Information

AbstractThe ovary is part of the reproductive system, possessing very important functions in the reproduction process (ovum and embryo transfer, providing a suitable environment for sperm capacitation, etc.). There are two types of cells in the fallopian tubes: alveolar and secretive cells. These study shows the metabolic processes in pig oviductal epithelial cells associated with the activation of signaling pathways of amino acids metabolism and degradation during long-term in vitro culture. Oviductal epithelial cells from 45 colonies in the anestrous phase of the estrous cycle have been utilized in this study. RNA extract from the OEC primary cultures was pooled after 24h, 7days, 15 days and 30 days from the beginning of culture and the transcriptome investigated by Affymetrix® Porcine Gene 1.1 ST. From the whole transcript that consisted of 2009 different genes, 1537 were upregulated and 995 were downregulated after 7 days of culture, 1471 were upregulated and 1061 were downregulated after 15 days of culture and 1329 were upregulated and 1203 were downregulated after 30 days of culture. The results of these studies provide, for the first time, information on the activation of metabolic pathways of amino acids such as valine, leucine, isoleucine, cysteine, and methionine in the investigated tissue. They also indicate genes that may be OECs-specific genetic markers that are expressed or upregulated during long-term in vitro culture.

scholarly journals Effect of Short-Term Stimulation with Interleukin-1βand Differentiation Medium on Human Mesenchymal Stromal Cell Paracrine Activity in Coculture with Osteoblasts

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Jan O. Voss ◽  
Claudia Loebel ◽  
Jennifer J. Bara ◽  
Marc Anton Fussinger ◽  
Fabian Duttenhoefer ◽  
...  
Keyword(s):  
Osteogenic Differentiation ◽  
Interleukin 1 ◽  
Regulatory Function ◽  
Regulatory Effect ◽  
Differentiation Medium ◽  
Novel Approach ◽  
Osteogenic Gene Expression ◽  
Transwell System

Introduction.Human mesenchymal stromal cells (hMSCs) exhibit the potential to accelerate bone healing by enhanced osteogenic differentiation. Interleukin-1βis highly expressed during fracture healing and has been demonstrated to exert a significant impact on the differentiation behaviour of hMSCs. Here, we investigate the effect of 2-hour IL-1βstimulation on the differentiation and paracrine activity of hMSCs in coculture with osteosarcoma cellsin vitro.Methods.hMSCs from 3 donors were incubated for 2 hours with 10 ng/mL IL-1βand subsequently cocultured with MG63-GFP cells either in control or in differentiation medium in a transwell system for 28 days. Genetic and functional effects were investigated.Results.hMSCs cultured in control medium exhibited a regulatory effect on cocultured MG63-GFP cells, resulting in upregulation of osteogenic gene expression in combination with increased ALP activity. However, while stimulated hMSCs cultured under differentiation conditions exhibit signs of osteogenic differentiation, osteogenic differentiation also caused an impaired regulatory effect on the cocultured MG63-GFP cells.Conclusion.Short stimulation of hMSCs has the potential to modify their long-term behaviour. In addition, undifferentiated hMSCs are able to regulate osteoblast differentiation; however, this regulatory function is lost upon osteogenic differentiationin vitro. This offers a novel approach for clinical cell therapy protocols.

Nano-Scale Evaluation of Surface Morphology Before and After Environmental Exposure In Vitro of an Advanced Alumina/Zirconia Composite for Arthroplastic Applications

2010 ◽  
Vol 76 ◽  
pp. 224-228
Author(s):  
Kengo Yamamoto ◽  
Giuseppe Pezzotti
Keyword(s):  
Surface Roughness ◽  
Environmental Exposure ◽  
Hip Prostheses ◽  
Force Microscopy ◽  
Head Surface ◽  
Before And After ◽  
Moist Environment

In view of the imminent release on the Japanese market of hip prostheses made of an advanced alumina/zirconia, we performed morphologic and spectroscopic assessments of their surfaces with high spatial resolution. Femoral heads were characterized to a degree of statistical accuracy in the as-received state and after long-term exposures in vapor-moist environment. Surface and sub-surface screening was made by atomic force microscopy (AFM) and by confocal Raman spectroscopy, respectively. AFM scanning was systematically repeated with nanometer resolution on portions of surface as large as several tens of micrometers, randomly selected on the head surface, while in-depth scanning by the Raman probe allowed non-destructive analysis of phase structure in the sub-surface slab of material. Polymorphic transformation in zirconia was confined to the first few micrometers below the surface and involved no significant increase in surface roughness even after long-term environmental exposure. Surface roughness lied in a range <10 nm after environmental exposures up to 100 h, corresponding to an exposure time in vivo of several human lifetimes (i.e., according to experimentally derived thermal activation energy).

Investigating the surface changes of silicon in vitro within physiological environments for neurological application

2014 ◽  
Vol 1621 ◽  
pp. 237-242 ◽  
Author(s):  
Maysam Nezafati ◽  
Stephen E. Saddow ◽  
Christopher L. Frewin
Keyword(s):  
Surface Roughness ◽  
Construction Materials ◽  
Large Change ◽  
Neural Implants ◽  
Neural Recordings ◽  
Atomic Force ◽  
Initial Stage ◽  
Artificial Cerebrospinal Fluid

ABSTRACTSilicon has been used as one of the primary substrates for micro-machined intra-cortical neural implants (INI). The presence of various ions in the extracellular environment combined with cellular biological activity establishes a harsh, corrosive environment in the brain for INI, and as such, a long-term implant’s construction materials must be able to resist these environments. We have examined if environmental components could contribute to changes in the material, which in turn may be a contributing factor to the decreased long-term reliability in INI optimal neural recordings, which have prevented clinical use these devices for the last 4 decades. We tested silicon in artificial cerebrospinal fluid (ACSF), Dulbecco's modified eagle medium (DMEM), and H4 cells cultured within DMEM for 96 hours at 37°C as three various physiological environments to investigate the material degradation. We have observed that Si samples immersed in only DMEM and ACSF showed very minor surface alterations. However, Si samples cultured with H4 cells exhibited a large change in surface roughness from 0.24±0.04 nm to 4.85 nm. The scanning electron microscope (SEM) micrographs showed the presence of pyramid shaped pits. Further characterization with atomic force microscope (AFM) verified this result and quantified the severe changes in the surface roughness of these samples. At this initial stage of the investigation, we are endeavoring to identify the cause of these changes to the Si surface, but based on our observations, we believe that the increased corrosion could be result of chemical products released into the surrounding environment by the cells.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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