In Vitro Examination of Poly(glycerol sebacate) Degradation Kinetics: Effects of Porosity and Cure Temperature

2014 ◽  
Vol 1621 ◽  
pp. 87-92 ◽  
Author(s):  
Nadia M. Krook ◽  
Courtney LeBlon ◽  
Sabrina S. Jedlicka
Keyword(s):  
Biomedical Applications ◽  
Degradation Kinetics ◽  
Morphological Changes ◽  
Scanning Calorimetry ◽  
Tissue Engineering Scaffolds ◽  
Degradation Study ◽  
Wide Range ◽  
Thermal Changes ◽  
Cure Temperature

ABSTRACTPoly(glycerol sebacate) (PGS) is a biodegradable and biocompatible elastomer that has been used in a wide range of biomedical applications. While a porous format is common for tissue engineering scaffolds, to allow cell ingrowth, PGS degradation has been primarily studied in a nonporous format. The purpose of this research was to investigate the degradation of porous PGS at three frequently used cure temperatures: 120°C, 140°C, and 165°C. The thermal, chemical, mechanical, and morphological changes were examined using thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, compression testing, and scanning electron microscopy. Over the course of the 16-week degradation study, the samples’ pores collapsed. The specimens cured at 120°C demonstrated the most degradation and became gel-like after 16 weeks. Thermal changes were most evident in the 120°C and 140°C cure PGS specimens, as shifts in the melting and recrystallization temperatures occurred. Porous samples cured at all three temperatures displayed a decrease in compressive modulus after 16 weeks. This in vitro study helped to elucidate the effects of porosity and cure temperature on the biodegradation of PGS and will be valuable for the design of future PGS scaffolds.

scholarly journals Fabrication of Micro/Nanofibrous Scaffolds using a Robotic Manipulator and Their Application for Tissue Engineering

2020 ◽  
Author(s):  
Andrii Shynkarenko ◽  
Dekel Azulay ◽  
Sarka Hauzerova ◽  
Andrea Klapstova ◽  
Michal Moucka ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Dominant Role ◽  
Robotic Manipulator ◽  
Wound Dressings ◽  
Scanning Calorimetry ◽  
Tissue Engineering Scaffolds ◽  
Nanofibrous Scaffolds ◽  
Dimensional Network ◽  
Wide Range

Abstract Background: Nanofibrous materials currently find a wide range of medical and bioengineering applications including tissue-engineering scaffolds, sutures, and wound dressings. Recently, production of nanofibrous materials via Electrospinning has played a dominant role in this area. Here we introduce an alternative method, which we call the drawing method, which allows us to produce individual micro and nanofibers and to position them precisely into a two-dimensional network. Results: The creation of such nano or micro fibrous networks is enabled thanks to a special arm-like robotic manipulator that we have designed, including its control system software. In this work we produced and tested microfibrous scaffolds of precise geometry made of two different biodegradable polymers: Polycaprolactone and Polylactide – Polycaprolactone copolymer. The microfibrous networks produced thereby were analyzed using a scanning electronic microscope and tested in vitro for cell adhesion and proliferation. The crystallinity of the resulting manufactured polymeric structures was evaluated using differential scanning calorimetry. Conclusions: The mechanical drawing of individual microfibers presented in this article is a promising method to produce precisely oriented nano and microfibrous structures for technical as well as bioengineering applications. Our results indicate that the mechanical drawing of microfibers expands the possibilities for the preparation of tissue engineering scaffolds. Therefore, we believe that the range of applications of mechanical fiber drawing may soon expand.

scholarly journals Individual Expression of Hepatitis A Virus 3C Protease Induces Ferroptosis in Human Cells In Vitro

2021 ◽  
Vol 22 (15) ◽  
pp. 7906
Author(s):  
Alexey A. Komissarov ◽  
Maria A. Karaseva ◽  
Marina P. Roschina ◽  
Andrey V. Shubin ◽  
Nataliya A. Lunina ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Proteolytic Enzymes ◽  
Morphological Changes ◽  
Human Cells ◽  
Mitochondrial Potential ◽  
3C Protease ◽  
Wide Range

Regulated cell death (RCD) is a fundamental process common to nearly all living beings and essential for the development and tissue homeostasis in animals and humans. A wide range of molecules can induce RCD, including a number of viral proteolytic enzymes. To date, numerous data indicate that picornaviral 3C proteases can induce RCD. In most reported cases, these proteases induce classical caspase-dependent apoptosis. In contrast, the human hepatitis A virus 3C protease (3Cpro) has recently been shown to cause caspase-independent cell death accompanied by previously undescribed features. Here, we expressed 3Cpro in HEK293, HeLa, and A549 human cell lines to characterize 3Cpro-induced cell death morphologically and biochemically using flow cytometry and fluorescence microscopy. We found that dead cells demonstrated necrosis-like morphological changes including permeabilization of the plasma membrane, loss of mitochondrial potential, as well as mitochondria and nuclei swelling. Additionally, we showed that 3Cpro-induced cell death was efficiently blocked by ferroptosis inhibitors and was accompanied by intense lipid peroxidation. Taken together, these results indicate that 3Cpro induces ferroptosis upon its individual expression in human cells. This is the first demonstration that a proteolytic enzyme can induce ferroptosis, the recently discovered and actively studied type of RCD.

scholarly journals Synthesis and Evaluation of AlgNa-g-poly(QCL-co-HEMA) Hydrogels as Platform for Chondrocyte Proliferation and Controlled Release of Betamethasone

2021 ◽  
Vol 22 (11) ◽  
pp. 5730
Author(s):  
Jomarien García-Couce ◽  
Marioly Vernhes ◽  
Nancy Bada ◽  
Lissette Agüero ◽  
Oscar Valdés ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Controlled Release ◽  
Biomedical Applications ◽  
Release Kinetics ◽  
Cell Types ◽  
Tissue Engineering Scaffolds ◽  
Almost All ◽  
Scanning Electron

Hydrogels obtained from combining different polymers are an interesting strategy for developing controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using a different concentration of the components. The hydrogels were characterized by Fourier transform-infrared spectroscopy, scanning electron microscopy, and a swelling degree. Betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at a different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner for up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay showed that almost all hydrogels are cytocompatibles and an increase of proliferation in both cell types after one week of incubation was observed by the Live/Dead® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics, and biocompatibility.

scholarly journals Effects of innate immune receptor stimulation on extracellular α-synuclein uptake and degradation by brain resident cells

2021 ◽  
Author(s):  
Changyoun Kim ◽  
Somin Kwon ◽  
Michiyo Iba ◽  
Brian Spencer ◽  
Edward Rockenstein ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Morphological Changes ◽  
Direct Interaction ◽  
Innate Immune ◽  
Pathological Feature ◽  
Tlr2 Expression ◽  
Immune Receptors ◽  
Age Related ◽  
Stimulation Of

AbstractSynucleinopathies are age-related neurological disorders characterized by the progressive deposition of α-synuclein (α-syn) aggregates and include Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). Although cell-to-cell α-syn transmission is thought to play a key role in the spread of α-syn pathology, the detailed mechanism is still unknown. Neuroinflammation is another key pathological feature of synucleinopathies. Previous studies have identified several immune receptors that mediate neuroinflammation in synucleinopathies, such as Toll-like receptor 2 (TLR2). However, the species of α-syn aggregates varies from study to study, and how different α-syn aggregate species interact with innate immune receptors has yet to be addressed. Therefore, we investigated whether innate immune receptors can facilitate the uptake of different species of α-syn aggregates. Here, we examined whether stimulation of TLRs could modulate the cellular uptake and degradation of α-syn fibrils despite a lack of direct interaction. We observed that stimulation of TLR2 in vitro accelerated α-syn fibril uptake in neurons and glia while delaying the degradation of α-syn in neurons and astrocytes. Internalized α-syn was rapidly degraded in microglia regardless of whether TLR2 was stimulated. However, cellular α-syn uptake and degradation kinetics were not altered by TLR4 stimulation. In addition, upregulation of TLR2 expression in a synucleinopathy mouse model increased the density of Lewy-body-like inclusions and induced morphological changes in microglia. Together, these results suggest that cell type-specific modulation of TLR2 may be a multifaceted and promising therapeutic strategy for synucleinopathies; inhibition of neuronal and astroglial TLR2 decreases pathogenic α-syn transmission, but activation of microglial TLR2 enhances microglial extracellular α-syn clearance.

A Review on Application of Novel Solid Nanostructures in Drug Delivery

2018 ◽  
Vol 53 ◽  
pp. 22-36 ◽  
Author(s):  
Habibollah Faraji ◽  
Reza Nedaeinia ◽  
Esmaeil Nourmohammadi ◽  
Bizan Malaekeh-Nikouei ◽  
Hamid Reza Sadeghnia ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Therapy ◽  
Biomedical Applications ◽  
Imaging Biomarkers ◽  
Cellular Functions ◽  
Scientific Innovation ◽  
Wide Range ◽  
Targeted Drug

Nanotechnology as a multidisciplinary and scientific innovation plays an important role in numerous biomedical applications, such as molecular imaging, biomarkers and biosensors and also drug delivery. A wide range of studies have been conducted on using of nanoparticles for early diagnosis and targeted drug therapy of various diseases. In fact, the small size, customized surface, upgraded solubility, or multi-functionality of nanoparticles enabled them to interact with complex cellular functions in new ways which opened many doors and created new biomedical applications. These studies demonstrated that nanotechnology vehicles can formulate biological products effectively, and this nano-formulated products with a potent ability against different diseases, were represented to have better biocompatibility, bioaccessibility and efficacy, under in vitro and in vivo conditions.

scholarly journals Development of 3D Bioactive Nanocomposite Scaffolds Made from Gelatin and Nano Bioactive Glass for Biomedical Applications

2010 ◽  
Vol 19 (2) ◽  
pp. 096369351001900 ◽  
Author(s):  
M. Mozafari ◽  
F. Moztarzadeh ◽  
M. Rabiee ◽  
M. Azami ◽  
N. Nezafati ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bioactive Glass ◽  
Biomedical Applications ◽  
Cell Attachment ◽  
Tissue Engineering Scaffolds ◽  
Study Results ◽  
Nanocomposite Scaffold ◽  
Nanocomposite Scaffolds ◽  
First Time

In this research, macroporous, mechanically competent and bioactive nanocomposite scaffolds have been fabricated from cross-linked gelatine (Gel) and nano bioactive glass (nBG) through layer solvent casting combined with freeze-drying and lamination techniques. This study has developed a new composition to produce a new bioactive nanocomposite which is porous with interconnected microstructure, pore sizes are 200-500 μm, porosity are 72%-86%. Also, we have reported formation of chemical bonds between nBG and Gel for the first time. Finally, the in vitro cytocompatability of the scaffolds was assessed using MTT assay and cell attachment study. Results indicated no sign of toxicity and cells found to be attached to the pore walls offered by the scaffolds. These results suggested that the developed nanocomposite scaffold possess the prerequisites for bone tissue engineering scaffolds and it can be used for tissue engineering applications.

scholarly journals Inclusion Complexes of β and HPβ-Cyclodextrin with α, β Amyrin and In Vitro Anti-Inflammatory Activity

Biomolecules ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 241 ◽  
Author(s):  
Walter Ferreira da Silva Júnior ◽  
Danielle Lima Bezerra de Menezes ◽  
Luana Carvalho de Oliveira ◽  
Letícia Scherer Koester ◽  
Patrícia Danielle Oliveira de Almeida ◽  
...  
Keyword(s):  
Inclusion Complexes ◽  
Biological Activities ◽  
Physicochemical Characterization ◽  
Inflammatory Activity ◽  
Scanning Calorimetry ◽  
Promising Alternative ◽  
Wide Range ◽  
Natural Mixture ◽  
Anti Inflammatory

α, β amyrin (ABAM) is a natural mixture of pentacyclic triterpenes that has a wide range of biological activities. ABAM is isolated from the species of the Burseraceae family, in which the species Protium is commonly found in the Amazon region of Brazil. The aim of this work was to develop inclusion complexes (ICs) of ABAM and β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD) by physical mixing (PM) and kneading (KN) methods. Interactions between ABAM and the CD’s as well as the formation of ICs were confirmed by physicochemical characterization in the solid state by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). Physicochemical characterization indicated the formation of ICs with both βCD and HPβCD. Such ICs were able to induce changes in the physicochemical properties of ABAM. In addition, the formation of ICs with cyclodextrins showed to be an effective and promising alternative to enhance the anti-inflammatory activity and safety of ABAM.

Design Considerations and Assays for Hemocompatibility of FDA-Approved Nanoparticles

2019 ◽  
Vol 46 (05) ◽  
pp. 637-652
Author(s):  
Amit K. Saha ◽  
Min-Yi S. Zhen ◽  
Folarin Erogbogbo ◽  
Anand K. Ramasubramanian
Keyword(s):  
Biomedical Applications ◽  
Inflammatory Responses ◽  
Mode Of Delivery ◽  
Systemic Circulation ◽  
In Vitro Assays ◽  
Cardiovascular Tissues ◽  
Wide Range ◽  
The Us ◽  
Imaging Sensors

AbstractNanoparticles have numerous biomedical applications including, but not limited to, targeted drug delivery, diagnostic imaging, sensors, and implants for a wide range of diseases including cancer, diabetes, heart disease, and tuberculosis. Although the mode of delivery of the nanoparticles depends on the application and the disease, the nanoparticles are often in immediate contact with the systemic circulation either because of intravenous administration or their ability to enter the bloodstream with relative ease or their longer survival time in circulation. Once in circulation, the nanoparticles may elicit unintended hemostatic and inflammatory responses, and hence the design of nanoparticles for therapeutic applications should take broad hemocompatibility concerns into consideration. In this review, we present the principles underlying the structural and functional design of various classes of nanoparticles that are currently approved by the US Food and Drug Administration, categorize these particles based on their interactions with cardiovascular tissues and ensuing adverse events, and also describe various in vitro assays that may be used evaluate their hemocompatibility.

scholarly journals Thymodepressin—Unforeseen Immunosuppressor

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6550
Author(s):  
Vladislav I. Deigin ◽  
Julia E. Vinogradova ◽  
Dmitry L Vinogradov ◽  
Marina S. Krasilshchikova ◽  
Vadim T. Ivanov
Keyword(s):  
Experimental Evidence ◽  
Synthetic Peptide ◽  
Biomedical Applications ◽  
Biological Properties ◽  
Peptide Drug ◽  
Wide Range ◽  
History Of ◽  
Available Information

The paper summarizes the available information concerning the biological properties and biomedical applications of Thymodepressin. This synthetic peptide drug displays pronounced immunoinhibitory activity across a wide range of conditions in vitro and in vivo. The history of its unforeseen discovery is briefly reviewed, and the current as well as potential expansion areas of medicinal practice are outlined. Additional experimental evidence is obtained, demonstrating several potential advantages of Thymodepressin over another actively used immunosuppressor drug, cyclosporin A.

scholarly journals The novel modeling approach for the study of thermal degradation of PMMA/nanooxide systems

2019 ◽  
Vol 38 (1) ◽  
pp. 95
Author(s):  
Mirjana Jovicic ◽  
Oskar Bera ◽  
Katalin Meszaros Szecsenyi ◽  
Predrag Kojic ◽  
Jaroslava Budinski-Simendic ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Degradation Kinetics ◽  
The Novel ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Total Mass Loss ◽  
Thermal Changes ◽  
Silica Alumina ◽  
Individual Contributions ◽  
Kinetics Of

PMMA (poly(methyl methacrylate)) nanocomposites differing in their nature, size, and surface area were prepared containing one volume percent of silica, alumina or titania. These samples and pure PMMA were prepared in order to analyze how the presence of nanooxides affects the thermal stability and degradation kinetics of the materials. A detailed study of thermal degradation and thermal changes was performed by Simultaneous Thermogravimetry and Differential Scanning Calorimetry (SDT). The proposed mathematical model, including all three heating rates in one minimizing function, well fitted all TGA data obtained with a very high coefficient of correlation. This enabled an assessment of four decomposition steps of the PMMA samples and a calculation of their activation energies and individual contributions to total mass loss. The addition of the largest nanoparticles (titania) caused the highest activation energy for each DTG stage of the PMMA/nanooxide systems. The enhancement of head-to-head H–H bonding strength was achieved by addition of alumina and titania. The influence of the size and nature of nanoparticles on the glass transition temperature of prepared PMMA systems was also determined.

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