scholarly journals In-Vivo Microsystems: A Review

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4953 ◽  
Author(s):  
Paddy French
Keyword(s):  
Medical Information ◽  
High Volume ◽  
The Body ◽  
Cardiac Catheter ◽  
Silicon Devices ◽  
Silicon Sensors ◽  
Cardiac Catheters ◽  
Single Sensor

In-vivo sensors yield valuable medical information by measuring directly on the living tissue of a patient. These devices can be surface or implant devices. Electrical activity in the body, from organs or muscles can be measured using surface electrodes. For short term internal devices, catheters are used. These include cardiac catheter (in blood vessels) and bladder catheters. Due to the size and shape of the catheters, silicon devices provided an excellent solution for sensors. Since many cardiac catheters are disposable, the high volume has led to lower prices of the silicon sensors. Many catheters use a single sensor, but silicon offers the opportunity to have multi sensors in a single catheter, while maintaining small size. The cardiac catheter is usually inserted for a maximum of 72 h. Some devices may be used for a short-to-medium period to monitor parameters after an operation or injury (1–4 weeks). Increasingly, sensing, and actuating, devices are being applied to longer term implants for monitoring a range of parameters for chronic conditions. Devices for longer term implantation presented additional challenges due to the harshness of the environment and the stricter regulations for biocompatibility and safety. This paper will examine the three main areas of application for in-vivo devices: surface devices and short/medium-term and long-term implants. The issues of biocompatibility and safety will be discussed.

scholarly journals Biocompatibility of Bacterial Magnetosomes as MRI Contrast Agent: A Long-Term In Vivo Follow-Up Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1235
Author(s):  
Xiaohui Nan ◽  
Wenjia Lai ◽  
Dan Li ◽  
Jiesheng Tian ◽  
Zhiyuan Hu ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Magnetic Domain ◽  
Bilayer Membrane ◽  
The Body ◽  
Mri Contrast Agent ◽  
Mri Imaging ◽  
Mri Contrast

Derived from magnetotactic bacteria (MTB), magnetosomes consist of magnetite crystals enclosed within a lipid bilayer membrane and are known to possess advantages over artificially synthesized nanoparticles because of the narrow size distribution, uniform morphology, high purity and crystallinity, single magnetic domain, good biocompatibility, and easy surface modification. These unique properties have increasingly attracted researchers to apply bacterial magnetosomes (BMs) in the fields of biology and medicine as MRI imaging contrast agents. Due to the concern of biosafety, a long-term follow-up of the distribution and clearance of BMs after entering the body is necessary. In this study, we tracked changes of BMs in major organs of mice up to 135 days after intravenous injection using a combination of several techniques. We not only confirmed the liver as the well-known targeted organs of BMs, but also found that BMs accumulated in the spleen. Besides, two major elimination paths, as well as the approximate length of time for BMs to be cleared from the mice, were revealed. Together, the results not only confirm that BMs have high biocompatibility, but also provide a long-term in-vivo assessment which may further help to forward the clinical applications of BMs as an MRI contrast agent.

Modifying Brushite Cement Degradation Using Calcium Alginate Beads

2007 ◽  
Vol 361-363 ◽  
pp. 311-314 ◽  
Author(s):  
Liam M. Grover ◽  
Sarika Patel ◽  
Y. Hu ◽  
Uwe Gbureck ◽  
J.E. Barralet
Keyword(s):  
Calcium Alginate ◽  
Alginate Beads ◽  
The Body ◽  
Cement Matrix ◽  
Calcium Alginate Beads ◽  
Long Term Stability ◽  
The Matrix ◽  
Implant Degradation

The hydrolysis of brushite in calcium phosphate cements to form hydroxyapatite is known to result in the long term stability of the material in the body. It has previously been established that this hydrolysis reaction can be influenced by implant volume, media refreshment rate and media composition. In this study, the effect of macroporosity on the rate of degradation of the material is investigated. Macroporosity was incorporated into the material using calcium alginate beads mixed into the cement paste. The inclusion of the calcium alginate beads did not influence the degree of conversion of the material and allowed the incorporation of porosity at up to maximum of 57%. The macroporosity weakened the cement matrix (from 46.5 to 3.2 MPa). When aged the brushite in the macroporous cement dissolved completely from the matrix resulting in a weight loss of 60wt% in a period of 28 days. This suggests that the controlled incorporation of calcium alginate beads into brushite cements in vivo can be used to control implant degradation rate.

scholarly journals Effects of long-term in vivo micro-CT imaging on hallmarks of osteopenia and frailty in aging mice

2020 ◽  
Author(s):  
Ariane C. Scheuren ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Body Weight ◽  
Aging Process ◽  
Frailty Index ◽  
Ct Imaging ◽  
Morphometric Parameters ◽  
The Body ◽  
The Other ◽  
Micro Ct

AbstractIn vivo micro-CT has already been used to monitor microstructural changes of bone in mice of different ages and in models of age-related diseases such as osteoporosis. However, as aging is accompanied by frailty and subsequent increased sensitivity to external stimuli such as handling and anesthesia, the extent to which longitudinal imaging can be applied in aging studies remains unclear. Consequently, the potential of monitoring individual mice during the entire aging process – from healthy to frail status – has not yet been exploited. In this study, we assessed the effects of long-term in vivo micro-CT imaging - consisting of 11 imaging sessions over 20 weeks - on hallmarks of aging both on a local (i.e., static and dynamic bone morphometry) and systemic (i.e., frailty index (FI) and body weight) level at various stages of the aging process. Furthermore, using a premature aging model (PolgA(D257A/D257A)), we assessed whether these effects differ between genotypes.The 6th caudal vertebrae of 4 groups of mice (PolgA(D257A/D257A) and PolgA(+/+)) were monitored by in vivo micro-CT every 2 weeks. One group was subjected to 11 scans between weeks 20 and 40 of age, whereas the other groups were subjected to 5 scans between weeks 26-34, 32-40 and 40-46, respectively. The long-term monitoring approach showed small but significant changes in the static bone morphometric parameters compared to the other groups. However, no interaction effect between groups and genotype was found, suggesting that PolgA mutation does not render bone more or less susceptible to long-term micro-CT imaging. The differences between groups observed in the static morphometric parameters were less pronounced in the dynamic morphometric parameters. Moreover, the body weight and FI were not affected by more frequent imaging sessions. Finally, we observed that longitudinal designs including baseline measurements at young adult age are more powerful at detecting effects of in vivo micro-CT imaging on hallmarks of aging than cross-sectional comparisons between multiple groups of aged mice subjected to fewer imaging sessions.

scholarly journals Is Surface Metastability of Today’s Ceramic Bearings a Clinical Issue?

2021 ◽  
Vol 5 (10) ◽  
pp. 273
Author(s):  
Alessandro Alan Porporati ◽  
Laurent Gremillard ◽  
Jérôme Chevalier ◽  
Rocco Pitto ◽  
Marco Deluca
Keyword(s):  
Raman Spectroscopy ◽  
The Body ◽  
Clinical Issue ◽  
Surface Stability ◽  
In Vitro Aging ◽  
Aging Kinetics ◽  
Many Sources

Recent studies on zirconia-toughened alumina (ZTA) evidenced that in vivo aged implants display a much higher monoclinic zirconia content than expected from in vitro simulations by autoclaving. At the moment, there is no agreement on the source of this discrepancy: Some research groups ascribe it to the effect of mechanical impact shocks, which are generally not implemented in standard in vitro aging or hip walking simulators. Others invoke the effect of metal transfer, which should trigger an autocatalytic reaction in the body fluid environment, accelerating the kinetics of tetragonal-to-monoclinic transformation in vivo. Extrapolations of the aging kinetics from high (autoclave) to in vivo temperature are also often disputed. Last, Raman spectroscopy is by far the preferred method to quantify the amount of monoclinically transformed zirconia. There are, however, many sources of errors that may negatively affect Raman results, meaning that the final interpretation might be flawed. In this work, we applied Raman spectroscopy to determine the monoclinic content in as-received and in vitro aged ZTA hip joint implants, and in one long-term retrieval study. We calculated the monoclinic content with the most used equations in the literature and compared it with the results of X-ray diffraction obtained on a similar probe depth. Our results show, contrary to many previous studies, that the long-term surface stability of ZTA ceramics is preserved. This suggests that the Raman technique does not offer consistent and unique results for the analysis of surface degradation. Moreover, we discuss here that tetragonal-to-monoclinic transformation is also necessary to limit contact damage and wear stripe extension. Thus, the surface metastability of zirconia-containing ceramics may be a non-issue.

scholarly journals Senescent Cell Depletion Through Targeting BCL-Family Proteins and Mitochondria

2020 ◽  
Vol 11 ◽  
Author(s):  
Ying Fan ◽  
Jiaoqi Cheng ◽  
Huihong Zeng ◽  
Lijian Shao
Keyword(s):  
Adenine Nucleotide ◽  
The Body ◽  
Mitochondrial Dna Mutation ◽  
Dna Mutation ◽  
Unfolded Protein ◽  
Respiratory Complex I ◽  
Protein Response

Senescent cells with replicative arrest can be generated during genotoxic, oxidative, and oncogenic stress. Long-term retention of senescent cells in the body, which is attributed to highly expressed BCL-family proteins, chronically damages tissues mainly through a senescence-associated secretory phenotype (SASP). It has been documented that accumulation of senescent cells contributes to chronic diseases and aging-related diseases. Despite the fact that no unique marker is available to identify senescent cells, increased p16INK4a expression has long been used as an in vitro and in vivo marker of senescent cells. We reviewed five existing p16INK4a reporter mouse models to detect, isolate, and deplete senescent cells. Senescent cells express high levels of anti-apoptotic and pro-apoptotic genes compared to normal cells. Thus, disrupting the balance between anti-apoptotic and pro-apoptotic gene expression, such as ABT-263 and ABT-737, can activate the apoptotic signaling pathway and remove senescent cells. Mitochondrial abnormalities in senescent cells were also discussed, for example mitochondrial DNA mutation accumulation, dysfunctional mitophagy, and mitochondrial unfolded protein response (mtUPR). The mitochondrial-targeted tamoxifen, MitoTam, can efficiently remove senescent cells due to its inhibition of respiratory complex I and low expression of adenine nucleotide translocase-2 (ANT2) in senescent cells. Therefore, senescent cells can be removed by various strategies, which delays chronic and aging-related diseases and enhances lifespan and healthy conditions in the body.

scholarly journals Evaluation of γ-oryzanol Accumulation and Lipid Metabolism in the Body of Mice Following Long-Term Administration of γ-oryzanol

Nutrients ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 104 ◽  
Author(s):  
Eri Kobayashi ◽  
Junya Ito ◽  
Naoki Shimizu ◽  
Takumi Kokumai ◽  
Shunji Kato ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Plasma Lipids ◽  
Rice Bran Oil ◽  
The Body ◽  
Biologically Active ◽  
Lipid Lowering ◽  
Single Oral Administration ◽  
Term Administration

γ-Oryzanol (OZ), abundant in rice bran oil, has gained attention due to its physiological activities (e.g., lipid-lowering effects). However, the absorption and metabolism of orally ingested OZ have not yet been fully elucidated. In this study, diets containing normal or high contents of OZ were fed to obesity model mice for 8 weeks, and OZ concentrations in plasma and organs were analyzed by HPLC-MS/MS. To evaluate the relationship between OZ accumulation and lipid metabolism in vivo, lipid concentrations in the mice plasma and liver were also measured. As a result, the accumulation of intact OZ in plasma and organs was seen in mice fed diets containing OZ, where mice fed diets containing higher OZ contents demonstrated higher levels of OZ accumulation and lower amounts of plasma lipids. These results, in combination with our additional data from a single oral administration test, suggest the possibility that intact OZ, along with its metabolites (e.g., ferulic acid), is biologically-active.

scholarly journals A Rationally Designed Novel Polymer for Safe and Synergistic Delivery of High Dose Bortezomib, Pomalidomide/Lenalidomide, and Dexamethasone for Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4681-4681
Author(s):  
Alexandre Detappe ◽  
Hung Nguyen ◽  
Clelia Mathieu ◽  
Yivan Jiang ◽  
Michael Agius ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Combination ◽  
Standard Of Care ◽  
The Body ◽  
Term Survival ◽  
Long Term Survival ◽  
Specific Concentration ◽  
Multiple Drugs

Abstract Introduction. Synergistic delivery of free drugs is highly challenging due to each drug's unique pharmacokinetics and biodistribution profiles. The standard of care Bortezomib, Pomalidomide/Lenalidomide, and Dexamethasone only demonstrates synergy in a specific concentration window. This specific concentration window has been proven difficult to reach using free drugs. Whereas the Bortezomib, Pomalidomide/Lenalidomide, and Dexamethasone drug combination is the standard of care for patients, an improved method to deliver drugs more specifically to the tumor in higher concentration and at their synergistic ratios would greatly improve the clinical outcome of Multiple Myeloma patients treatments. Methods and Results. We developed a novel 10 nm biodegradable bottlebrush polymer made of various PEG macromonomers conjugated to clinically used Myeloma drugs, including Bortezomib, Pomalidomide, Lenalidomide, and Dexamethasone. By combining the different macromonomer-drug conjugates together, we defined the most synergistic drug ratio by using the Chou-Talalay method in MM.1S, and KMS11 cell lines. Before evaluating the efficacy of the combination therapy in-vivo, we determined the maximum tolerated dose (MTD) for the Bortezomib bottlebrush alone by monitoring body weight loss, performing H&E staining in all major organs, and performing blood test panels. We successfully injected up to 25x the tolerated dose of free Bortezomib (0.75 mg/kg once a week) with our novel bottlebrush polymer conjugated to Bortezomib (18.75 mg/kg) without signs of toxicity in healthy Balb/c mice. We next evaluated the efficacy of Bortezomib bottlebrush in an orthotopic model of MM.1SGFP+/Luc+ Multiple Myeloma. We determined by fluorescence imaging of harvested organs and by flow cytometry that approx. 5% of the injected dose of bottlebrush Bortezomib (0.95 mg/kg) accumulated in the bone marrow. As a result, this improved and safer delivery technique allowed us to increase by 12 and 10 days the long-term survival of the MM.1SGFP+/Luc+ SCID mice, as compared to free Bortezomib (0.75 mg/kg) and low dose Bortezomib bottlebrush (0.75 mg/kg), respectively (p-value = 0.038, Mann-Whitney). In order to improve the long-term survival and to reach a complete response, we are currently investigating the use of the combination of the 3 drugs: Bortezomib, Pomalidomide, Dexamethasone simultaneously loaded in our bottlebrush at synergistic ratios and comparing the efficacy and toxicity of this combination to the 3 different single loaded bottlebrushes and to the efficacity and toxicity of the free drug combination. Conclusion. In conclusion, we developed a novel polymer enabling the controlled loading of multiple drugs at their optimal synergistic ratios. In addition, we demonstrated that the conjugation of the drug on our polymer enables the safe delivery of a higher tolerated dose in the body compared to treatments using free drugs and provided improved in-vivo therapeutic outcomes. Disclosures Ghobrial: Janssen: Consultancy; BMS: Consultancy; Celgene: Consultancy; Takeda: Consultancy.

Bioelectrodes modified with chitosan for long-term energy supply from the body

2015 ◽  
Vol 8 (3) ◽  
pp. 1017-1026 ◽  
Author(s):  
S. El Ichi ◽  
A. Zebda ◽  
J.-P. Alcaraz ◽  
A. Laaroussi ◽  
F. Boucher ◽  
...  
Keyword(s):  
Electrocatalytic Activity ◽  
Energy Supply ◽  
The Body ◽  
Mechanical Compression ◽  
Term Energy

We demonstrate that the use of a Chit–MWCNT matrix, fabricated by mechanical compression, allows construction of a biocompatible enzymatic biocathode which remains operational after more than five months in vivo (retaining 50% of its initial electrocatalytic activity).

scholarly journals Plants and Diabetes: Description, Role, Comprehension and Exploitation

2021 ◽  
Vol 22 (8) ◽  
pp. 3938
Author(s):  
Alessandra Durazzo ◽  
Massimo Lucarini ◽  
Antonello Santini
Keyword(s):  
Chronic Diseases ◽  
Diabetes Management ◽  
The Body ◽  
In Vivo Studies ◽  
Beneficial Effects ◽  
Treatment Of Diabetes ◽  
Main Components

Many plants have been known for centuries to have medicinal importance with potential beneficial effects on health. Phytotherapeutic compounds are well known to play a globally significant role, in particular in the management and treatment of various chronic diseases. Among these, diabetes can cause long term damage to the body other than having a relevant economic burden on society being among the costliest chronic diseases. This motivated the focus of the proposed Special Issue, intended to develop and exploit the potential role of plants in the management and treatment of diabetes. The main topics included are: (i) description and use of medicinal plants for diabetes management; (ii) the elucidation and delineation of their main components, properties (anti-hyperglycaemic, hypoglicaemic, anti-infiammatory, apoptotic agents, etc.), (iii) the mechanism of action (in vitro and in vivo studies); (iv) formulation of nutraceuticals, botanicals, and dietary supplements useful as tools as an alternative or support to anti-diabetic pharmacological therapies; (v) development of new markers.

scholarly journals A chronic photocapacitor implant for noninvasive neurostimulation with deep red light

2020 ◽  
Author(s):  
Malin Silverå-Ejneby ◽  
Marie Jakešová ◽  
Jose J. Ferrero ◽  
Ludovico Migliaccio ◽  
Zifang Zhao ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
High Performance ◽  
Ex Vivo ◽  
Red Light ◽  
The Body ◽  
Charge Generation ◽  
Efficient Charge ◽  
Potential Applicability

AbstractImplantable clinical neuroelectronic devices are limited by a lack of reliable, safe, and minimally invasive methods to wirelessly modulate neural tissue. Here, we address this challenge by using organic electrolytic photocapacitors (OEPCs) to perform chronic peripheral nerve stimulation via transduction of tissue-penetrating deep-red light into electrical signals. The operating principle of the OEPC relies on efficient charge generation by nanoscale organic semiconductors comprising nontoxic commercial pigments. OEPCs integrated on an ultrathin cuff are implanted, and light impulses at wavelengths in the tissue transparency window are used to stimulate from outside of the body. Typical stimulation parameters involve irradiation with pulses of 50-1000 μs length (638 or 660 nm), capable of actuating the implant about 10 mm below the skin. We detail how to benchmark performance parameters of OEPCs first ex vivo, and in vivo using a rat sciatic nerve. Incorporation of a microfabricated zip-tie mechanism enabled stable, long-term nerve implantation of OEPC devices in rats, with sustained ability to non-invasively mediate neurostimulation over 100 days. OEPC devices introduce a high performance, ultralow volume (0.1 mm3), biocompatible approach to wireless neuromodulation, with potential applicability to an array of clinical bioelectronics.

Sign in / Sign up

Export Citation Format

Share Document