scholarly journals Modified Nanodiamonds as a Means of Polymer Surface Functionalization. From Fouling Suppression to Biosensor Design

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2980
Author(s):  
Pavel V. Melnikov ◽  
Anastasia Yu. Alexandrovskaya ◽  
Alina O. Naumova ◽  
Nadezhda M. Popova ◽  
Boris V. Spitsyn ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Polymer Surface ◽  
Mixed Composition ◽  
Precise Control ◽  
Polar Groups ◽  
Bactericidal Properties ◽  
Wall Interaction ◽  
Biosensor Response

The development of different methods for tuning surface properties is currently of great interest. The presented work is devoted to the use of modified nanodiamonds to control the wetting and biological fouling of polymers using optical sensors as an example. We have shown that, depending on the type of modification and the amount of nanodiamonds, the surface of the same fluorinated polymer can have both bactericidal properties and, on the contrary, good adhesion to the biomaterial. The precise control of wetting and biofouling properties of the surface was achieved by the optimization of the modified nanodiamonds thermal anchoring conditions. In vitro and in vivo tests have shown that the fixation of amine functional groups leads to inhibition of biological activity, while the presence of a large number of polar groups of mixed composition (amide and acid chloride) promotes adhesion of the biomaterial and allows one to create a biosensor on-site. A comprehensive study made it possible to establish that in the first 5 days the observed biosensor response is provided by cells adhered to the surface due to the cell wall interaction. On the 7th day, the cells are fixed by means of the polysaccharide matrix, which provides much better retention on the surface and a noticeably greater response to substrate injections. Nevertheless, it is important to note that even 1.5 h of incubation is sufficient for the formation of the reliable bioreceptor on the surface with the modified nanodiamonds. The approach demonstrated in this work makes it possible to easily and quickly isolate the microbiome on the surface of the sensor and perform the necessary studies of its substrate specificity or resistance to toxic effects.

Evidence for an Increased Generation of Prostacyclin in the Microvasculature and an Impairment of the Platelet α-Granule Release in Chronic Renal Failure

1988 ◽  
Vol 60 (02) ◽  
pp. 205-208 ◽  
Author(s):  
Paul A Kyrle ◽  
Felix Stockenhuber ◽  
Brigitte Brenner ◽  
Heinz Gössinger ◽  
Christian Korninger ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Blood Clotting ◽  
Normal Subjects ◽  
Chronic Uraemia ◽  
Wall Interaction ◽  
End Stage ◽  
Granule Release

SummaryThe formation of prostacyclin (PGI2) and thromboxane A2 and the release of beta-thromboglobulin (beta-TG) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the micro vasculature made to determine bleeding time, was studied in patients with end-stage chronic renal failure undergoing regular haemodialysis and in normal subjects. In the uraemic patients, levels of 6-keto-prostaglandin F1α (6-keto-PGF1α) were 1.3-fold to 6.3-fold higher than the corresponding values in the control subjects indicating an increased PGI2 formation in chronic uraemia. Formation of thromboxane B2 (TxB2) at the site of plug formation in vivo and during whole blood clotting in vitro was similar in the uraemic subjects and in the normals excluding a major defect in platelet prostaglandin metabolism in chronic renal failure. Significantly smaller amounts of beta-TG were found in blood obtained from the site of vascular injury as well as after in vitro blood clotting in patients with chronic renal failure indicating an impairment of the a-granule release in chronic uraemia. We therefore conclude that the haemorrhagic diathesis commonly seen in patients with chronic renal failure is - at least partially - due to an acquired defect of the platelet a-granule release and an increased generation of PGI2 in the micro vasculature.

scholarly journals Sevoflurane Promotes Bactericidal Properties of Macrophages through Enhanced Inducible Nitric Oxide Synthase Expression in Male Mice

2019 ◽  
Vol 131 (6) ◽  
pp. 1301-1315 ◽  
Author(s):  
Thomas J. Gerber ◽  
Valérie C. O. Fehr ◽  
Suellen D. S. Oliveira ◽  
Guochang Hu ◽  
Randal Dull ◽  
...  
Keyword(s):  
Early Stage ◽  
No Synthase ◽  
Control Group ◽  
Male Mice ◽  
Proinflammatory Response ◽  
E Coli ◽  
Inducible No Synthase ◽  
Bactericidal Properties

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Sevoflurane with its antiinflammatory properties has shown to decrease mortality in animal models of sepsis. However, the underlying mechanism of its beneficial effect in this inflammatory scenario remains poorly understood. Macrophages play an important role in the early stage of sepsis as they are tasked with eliminating invading microbes and also attracting other immune cells by the release of proinflammatory cytokines such as interleukin-1β, interleukin-6, and tumor necrosis factor-α. Thus, the authors hypothesized that sevoflurane mitigates the proinflammatory response of macrophages, while maintaining their bactericidal properties. Methods Murine bone marrow–derived macrophages were stimulated in vitro with lipopolysaccharide in the presence and absence of 2% sevoflurane. Expression of cytokines and inducible NO synthase as well as uptake of fluorescently labeled Escherichia coli (E. coli) were measured. The in vivo endotoxemia model consisted of an intraperitoneal lipopolysaccharide injection after anesthesia with either ketamine and xylazine or 4% sevoflurane. Male mice (n = 6 per group) were observed for a total of 20 h. During the last 30 min fluorescently labeled E. coli were intraperitoneally injected. Peritoneal cells were extracted by peritoneal lavage and inducible NO synthase expression as well as E. coli uptake by peritoneal macrophages was determined using flow cytometry. Results In vitro, sevoflurane enhanced lipopolysaccharide-induced inducible NO synthase expression after 8 h by 466% and increased macrophage uptake of fluorescently labeled E. coli by 70% compared with vehicle-treated controls. Inhibiting inducible NO synthase expression pharmacologically abolished this increase in bacteria uptake. In vivo, inducible NO synthase expression was increased by 669% and phagocytosis of E. coli by 49% compared with the control group. Conclusions Sevoflurane enhances phagocytosis of bacteria by lipopolysaccharide-challenged macrophages in vitro and in vivo via an inducible NO synthase–dependent mechanism. Thus, sevoflurane potentiates bactericidal and antiinflammatory host-defense mechanisms in endotoxemia.

Modulation of Oxygen Tensions via Microfabricated Devices

2011 ◽  
Author(s):  
Shawn C. Oppegard ◽  
David T. Eddington
Keyword(s):  
Cellular Response ◽  
Tumor Oxygenation ◽  
Low Oxygen ◽  
Oxygen Control ◽  
Precise Control ◽  
Additional Equipment ◽  
Cancer Tumor ◽  
D Cell

Oxygen is a key modulator of many cellular pathways and plays an important role in a number of cellular behaviors. The hypoxic inducible factor 1α (HIF-1α) is often considered the master regulator of the cellular response to oxygen tension (1). HIF-1α is a transcription factor involved in angiogenesis, glucose transport and glycolysis, apoptosis, migration, and differentiation, among many other functions (2). Unfortunately devices permitting in vitro oxygen modulation fail to meet the needs of biomedical research due to the inability to effectively mimic conditions found in vivo. The gold standard for hypoxia work is the hypoxic chamber, but the tool requires hours for equilibration and is not effective at generating very low oxygen levels (3). As an example demonstrating this disadvantage, cancer tumor oxygenation can change in the span of minutes (4). Intermittent hypoxia, or the changing of oxygen over time, has been shown to be important in heart attack, stroke, and sleep apnea as well. Other microfluidic approaches, although offering more oxygen control, are often difficult to disseminate to other labs due to the requirement of specialized methods and equipment for their operation. In this work, a microfabricated technology has been developed to grant precise control the temporal and spatial oxygen concentration exposed to both cell monolayers in the multiwell plate as well as with 3-D cell-seeded constructs. The concept is adaptable to both pre-established and novel experiments depending on the needs of the researcher. The devices are simple to use and require minimal additional equipment beyond what is available to a standard cell culture lab.

scholarly journals Advancements and Potential Applications of Microfluidic Approaches—A Review

Chemosensors ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 46 ◽  
Author(s):  
Ishtiaq Ahmed ◽  
Zain Akram ◽  
Mohammed Bule ◽  
Hafiz Iqbal
Keyword(s):  
Modern Science ◽  
Cellular Interactions ◽  
Cellular Microenvironment ◽  
Engineering Research ◽  
Precise Control ◽  
Microfluidic Technology ◽  
Potential Applications ◽  
Micro Level

A micro-level technique so-called “microfluidic technology or simply microfluidic” has gained a special place as a powerful tool in bioengineering and biomedical engineering research due to its core advantages in modern science and engineering. Microfluidic technology has played a substantial role in numerous applications with special reference to bioscience, biomedical and biotechnological research. It has facilitated noteworthy development in various sectors of bio-research and upsurges the efficacy of research at the molecular level, in recent years. Microfluidic technology can manipulate sample volumes with precise control outside cellular microenvironment, at micro-level. Thus, enable the reduction of discrepancies between in vivo and in vitro environments and reduce the overall reaction time and cost. In this review, we discuss various integrations of microfluidic technologies into biotechnology and its paradigmatic significance in bio-research, supporting mechanical and chemical in vitro cellular microenvironment. Furthermore, specific innovations related to the application of microfluidics to advance microbial life, solitary and co-cultures along with a multiple-type cell culturing, cellular communications, cellular interactions, and population dynamics are also discussed.

scholarly journals Bioresorbable optical sensor systems for monitoring of intracranial pressure and temperature

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw1899 ◽  
Author(s):  
Jiho Shin ◽  
Zhonghe Liu ◽  
Wubin Bai ◽  
Yonghao Liu ◽  
Ying Yan ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Diagnostic Information ◽  
Resonance Imaging ◽  
Optical Components ◽  
Continuous Measurements ◽  
Fabry Perot ◽  
Magnetic Resonance Imaging Mri ◽  
Two Dimensional Photonic Crystal

Continuous measurements of pressure and temperature within the intracranial, intraocular, and intravascular spaces provide essential diagnostic information for the treatment of traumatic brain injury, glaucoma, and cardiovascular diseases, respectively. Optical sensors are attractive because of their inherent compatibility with magnetic resonance imaging (MRI). Existing implantable optical components use permanent, nonresorbable materials that must be surgically extracted after use. Bioresorbable alternatives, introduced here, bypass this requirement, thereby eliminating the costs and risks of surgeries. Here, millimeter-scale bioresorbable Fabry-Perot interferometers and two dimensional photonic crystal structures enable precise, continuous measurements of pressure and temperature. Combined mechanical and optical simulations reveal the fundamental sensing mechanisms. In vitro studies and histopathological evaluations quantify the measurement accuracies, operational lifetimes, and biocompatibility of these systems. In vivo demonstrations establish clinically relevant performance attributes. The materials, device designs, and fabrication approaches outlined here establish broad foundational capabilities for diverse classes of bioresorbable optical sensors.

scholarly journals An In Vitro Protocol for Recording From Spinal Motoneurons of Adult Rats

2008 ◽  
Vol 100 (1) ◽  
pp. 474-481 ◽  
Author(s):  
Jonathan S. Carp ◽  
Ann M. Tennissen ◽  
Donna L. Mongeluzi ◽  
Christopher J. Dudek ◽  
Xiang Yang Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Action Potential ◽  
Mechanical Stability ◽  
Pharmacological Study ◽  
Input Resistance ◽  
Spinal Motoneurons ◽  
Adult Rats ◽  
Precise Control

In vitro slice preparations of CNS tissue are invaluable for studying neuronal function. However, up to now, slice protocols for adult mammal spinal motoneurons—the final common pathway for motor behaviors—have been available for only limited portions of the spinal cord. In most cases, these preparations have not been productive due to the poor viability of motoneurons in vitro. This report describes and validates a new slice protocol that for the first time provides reliable intracellular recordings from lumbar motoneurons of adult rats. The key features of this protocol are: preexposure to 100% oxygen; laminectomy prior to perfusion; anesthesia with ketamine/xylazine; embedding the spinal cord in agar prior to slicing; and, most important, brief incubation of spinal cord slices in a 30% solution of polyethylene glycol to promote resealing of the many motoneuron dendrites cut during sectioning. Together, these new features produce successful recordings in 76% of the experiments and an average action potential amplitude of 76 mV. Motoneuron properties measured in this new slice preparation (i.e., voltage and current thresholds for action potential initiation, input resistance, afterhyperpolarization size and duration, and onset and offset firing rates during current ramps) are comparable to those recorded in vivo. Given the mechanical stability and precise control over the extracellular environment afforded by an in vitro preparation, this new protocol can greatly facilitate electrophysiological and pharmacological study of these uniquely important neurons and other delicate neuronal populations in adult mammals.

scholarly journals Neural Stimulation in vitro and in vivo by Photoacoustic Nanotransducers

2020 ◽  
Author(s):  
Yimin Huang ◽  
Ying Jiang ◽  
Xuyi Luo ◽  
Jiayingzi Wu ◽  
Haonan Zong ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Near Infrared ◽  
Neurological Diseases ◽  
Laser Pulses ◽  
Neural Stimulation ◽  
Nanosecond Laser ◽  
Genetic Method ◽  
Precise Control

AbstractNeuromodulation is an invaluable approach for study of neural circuits and clinical treatment of neurological diseases. Here, we report semiconducting polymer nanoparticles based photoacoustic nanotransducers (PANs) for neural stimulation. Our PANs strongly absorb light in the near-infrared second window and generate localized acoustic waves. PANs can also be surface-modified to selectively bind onto neurons. PAN-mediated activation of primary neurons in vitro is achieved with ten 3-nanosecond laser pulses at 1030 nm over a 3 millisecond duration. In vivo neural modulation of mouse brain activities and motor activities is demonstrated by PANs directly injected into brain cortex. With millisecond-scale temporal resolution, sub-millimeter spatial resolution and negligible heat deposition, PAN stimulation is a new non-genetic method for precise control of neuronal activities, opening potentials in non-invasive brain modulation.

scholarly journals A Membrane-Targeted Photoswitch Potently Modulates Neuronal Firing

2019 ◽  
Author(s):  
Mattia L. DiFrancesco ◽  
Francesco Lodola ◽  
Elisabetta Colombo ◽  
Luca Maragliano ◽  
Giuseppe M. Paternò ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Neural Activity ◽  
Neuronal Firing ◽  
Physiological Effects ◽  
Action Potential Firing ◽  
Polar Groups ◽  
Potential Firing ◽  
Spatio Temporal

ABSTRACTOptical technologies allowing modulation of neuronal activity at high spatio-temporal resolution are becoming paramount in neuroscience. We engineered novel light-sensitive molecules by adding polar groups to a hydrophobic backbone containing azobenzene and azepane moieties. We demonstrate that the probes stably partition into the plasma membrane, with affinity for lipid rafts, and cause thinning of the bilayer through their trans-dimerization in the dark. In neurons pulse-labeled with the compound, light induces a transient hyperpolarization followed by a delayed depolarization that triggers action potential firing. The fast hyperpolarization is attributable to a light-dependent decrease in capacitance due to membrane relaxation that follows disruption of the azobenzene dimers. The physiological effects are persistent and can be evoked in vivo after labeling the mouse somatosensory cortex. These data demonstrate the possibility to trigger neural activity in vitro and in vivo by modulating membrane capacitance, without directly affecting ion channels or local temperature.

scholarly journals Advances in Implantable Optogenetic Technology for Cardiovascular Research and Medicine

2021 ◽  
Vol 12 ◽  
Author(s):  
Micah K. Madrid ◽  
Jaclyn A. Brennan ◽  
Rose T. Yin ◽  
Helen S. Knight ◽  
Igor R. Efimov
Keyword(s):  
Optical Devices ◽  
Clinical Applications ◽  
Low Energy ◽  
Cation Channel ◽  
Clinical Translation ◽  
Cardiovascular Research ◽  
Precise Control ◽  
Analysis Of Function

Optogenetic technology provides researchers with spatiotemporally precise tools for stimulation, sensing, and analysis of function in cells, tissues, and organs. These tools can offer low-energy and localized approaches due to the use of the transgenically expressed light gated cation channel Channelrhodopsin-2 (ChR2). While the field began with many neurobiological accomplishments it has also evolved exceptionally well in animal cardiac research, both in vitro and in vivo. Implantable optical devices are being extensively developed to study particular electrophysiological phenomena with the precise control that optogenetics provides. In this review, we highlight recent advances in novel implantable optogenetic devices and their feasibility in cardiac research. Furthermore, we also emphasize the difficulties in translating this technology toward clinical applications and discuss potential solutions for successful clinical translation.

scholarly journals Near-infrared optogenetic engineering of photothermal nanoCRISPR for programmable genome editing

2020 ◽  
Vol 117 (5) ◽  
pp. 2395-2405 ◽  
Author(s):  
Xiaohong Chen ◽  
Yuxuan Chen ◽  
Huhu Xin ◽  
Tao Wan ◽  
Yuan Ping
Keyword(s):  
Genome Editing ◽  
Near Infrared ◽  
Irradiation Time ◽  
Inducible Promoter ◽  
Local Heat ◽  
Multiple Time ◽  
Precise Control ◽  
Multiple Time Points

We herein report an optogenetically activatable CRISPR-Cas9 nanosystem for programmable genome editing in the second near-infrared (NIR-II) optical window. The nanosystem, termed nanoCRISPR, is composed of a cationic polymer-coated Au nanorod (APC) and Cas9 plasmid driven by a heat-inducible promoter. The APC not only serves as a carrier for intracellular plasmid delivery but also can harvest external NIR-II photonic energy and convert it into local heat to induce the gene expression of the Cas9 endonuclease. Due to high transfection activity, the APC shows strong ability to induce a significant level of disruption in different genomic loci upon optogenetic activation. Moreover, the precise control of genome-editing activity can be simply programmed by finely tuning exposure time and irradiation time in vitro and in vivo and also enables editing at multiple time points, thus proving the sensitivity and inducibility of such an editing modality. The NIR-II optical feature of nanoCRISPR enables therapeutic genome editing at deep tissue, by which treatment of deep tumor and rescue of fulminant hepatic failure are demonstrated as proof-of-concept therapeutic examples. Importantly, this modality of optogenetic genome editing can significantly minimize the off-target effect of CRISPR-Cas9 in most potential off-target sites. The optogenetically activatable CRISPR-Cas9 nanosystem we have developed offers a useful tool to expand the current applications of CRISPR-Cas9, and also defines a programmable genome-editing strategy toward high precision and spatial specificity.

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