Computer-Aided 4D Modeling of Hydrolytic Degradation in Micropatterned Bioresorbable Membranes

2013 ◽  
Vol 7 (2) ◽  
Author(s):  
Ibrahim T. Ozbolat ◽  
Michelle Marchany ◽  
Joseph A. Gardella ◽  
Bahattin Koc
Keyword(s):  
Degradation Kinetics ◽  
Morphological Changes ◽  
Dynamic Geometry ◽  
Hydrolytic Degradation ◽  
Controlled Drug Release ◽  
Polymeric Membranes ◽  
Surface Erosion ◽  
Computer Aided ◽  
Kinetics Of

Real-time degradation studies of bioresorbable polymers can take weeks, months, and even years to conduct. For this reason, developing and validating mathematical models that describe and predict degradation can provide a means to accelerate the development of materials and devices for controlled drug release. This study aims to develop and experimentally validate a computer-aided model that simulates the hydrolytic degradation kinetics of bioresorbable polymeric micropatterned membranes for tissue engineering applications. Specifically, the model applies to circumstances that are conducive for the polymer to undergo surface erosion. The developed model provides a simulation tool enabling the prediction and visualization of the dynamic geometry of the degrading membrane. In order to validate the model, micropatterned polymeric membranes were hydrolytically degraded in vitro and the morphological changes were analyzed using optical microscopy. The model is then extended to predict spatiotemporal degradation kinetics of variational micropatterned architectures.

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.

Bioresorbable electrospun nanofibrous scaffolds loaded with bioactive molecules

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Chiara Gualandi ◽  
Piotr Wilczek ◽  
Maria Letizia Focarete ◽  
Gianandrea Pasquinelli ◽  
Michal Kawalec ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Degradation Kinetics ◽  
Hydrolytic Degradation ◽  
Mesenchymal Cells ◽  
Bioactive Molecules ◽  
Differential Interference Contrast Microscopy ◽  
Electrospinning Technique ◽  
Ki 67 ◽  
Nanofibrous Scaffolds

AbstractElectrospinning technology is used to fabricate sub-micrometric fiber mats made of a random equimolar poly(lactide-co-glycolide) copolymer (PLGA), whose in vitro hydrolytic degradation kinetics is investigated over a period of 49 days in phosphate buffer at 37 °C. The PLGA mats show a decrease of molecular weight (by GPC) from the very beginning of the experiment, whereas a macroscopic weight loss from the samples is appreciated (by gravimetry) only after 20 days of buffer exposure. The molar mass distribution curves remain monomodal during the degradation experiment suggesting that no acid auto-catalyzed hydrolysis, commonly observed in bulk specimens, occurs in sub-micrometric PLGA fibers. PLGA scaffolds containing Endothelial Growth Factor Supplement (ECGS) were also fabricated by electrospinning, from ECGS-containing polymer solutions. Mesenchymal cells derived from human bone marrow mononuclear cells were cultured in the presence of such ECGS-loaded PLGA scaffolds. Flow cytometry and Differential Interference Contrast microscopy were used to characterize the cell cultures over a 7 day period. The results of AnexinV/PI staining and of intranuclear Ki-67 protein expression show, together with concomitant cell morphology modifications, that growth factors released from the scaffolds support the survival, proliferation and growth of the mesenchymal cells. This result demonstrates that ECGS maintains its bioactivity upon release from the electrospun fibers and shows the versatility of the electrospinning technique.

scholarly journals Chemical-bromatological composition and in vitro ruminal kinetics of sugar cane silage with maniçoba

2018 ◽  
Vol 40 (1) ◽  
pp. 42569
Author(s):  
Francisco Allan Leandro de Carvalho ◽  
Percivaldo Xavier Resende ◽  
Clístenes Amorim Benicio ◽  
Jackson De Oliveira Siqueira ◽  
Daniel Ribeiro Menezes ◽  
...  
Keyword(s):  
Sugar Cane ◽  
Nutritive Value ◽  
Degradation Kinetics ◽  
Gas Production ◽  
Metabolizable Energy ◽  
Randomized Design ◽  
In Vitro Gas Production ◽  
Inclusion Level ◽  
Kinetics Of

The objective this study was to evaluate the effect of maniçoba supplementation in sugar cane silage with respect to chemical-bromatological composition and the in vitro degradation kinetics of the silage. This experiment was conducted in a completely randomized design with four treatments (maniçoba levels: 0, 20, 30, and 40%) and six repetitions. Silage samples were analyzed for their chemical-bromatological composition, digestible energy, metabolizable energy, total digestible nutrients, in vitro gas production and degradability parameters. The silage with higher inclusion level had better bromatological composition (p < 0.05) than the silage without maniçoba for CP, NDF, ADF and MM (6.49, 56.64, 38.66 and 4.52% versus 2.21, 70.96, 49.95 and 2.78%). Higher ME content (2.35 MJ kg-1 MS versus 1.85 MJ kg-1 MS), DE (2.87 Mcal kg-1 MS versus 2.25 Mcal kg-1 MS) and TDN (65.16% versus 51.11%), respectively. The highest values for gas production were also observed in silage with added maniçoba due to higher NFC content (34.87%). With an increase in the proportion of maniçoba, there was an increase in the soluble a fraction, b fraction, and thus a higher effective degradability of dry matter (46.56%). The addition of maniçoba improves the nutritive value of sugarcane silage.  

In vitro degradation kinetics of pure PLA and Mg/PLA composite: Effects of immersion temperature and compression stress

2017 ◽  
Vol 48 ◽  
pp. 468-478 ◽  
Author(s):  
Xuan Li ◽  
Chenglin Chu ◽  
Yalin Wei ◽  
Chenxi Qi ◽  
Jing Bai ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Compression Stress ◽  
In Vitro Degradation ◽  
Kinetics Of

The In Vitro Degradation Kinetics of Polyurethane Prodrug Materials

2011 ◽  
Vol 399-401 ◽  
pp. 1067-1070
Author(s):  
Chun Yan Li ◽  
Cong Cong Hu ◽  
Zhi Guo Wen ◽  
Sheng Xiong Dong
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Degradation Kinetics ◽  
Hplc Method ◽  
In Vitro Degradation ◽  
Erosion Mechanism ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

The method of high performance liquid chromatography (HPLC) is established to determine the content of antibacterial agent — ciprofloxacin (CF) in the degradation solution of ciprofloxacin-polyurethane (CFPU) and investigate the in vitro degradation kinetics by plotting and fitting the cumulative release curves to inspect the effects of different medium and different concentrations on drug release. The results showed that the HPLC method is accurate, reliable and simple. The drug-release of CFPU was bioresponsive and could be accorded with first order kinetics. It was observed that CF was released from CFPU by a combination of diffusion and erosion mechanism, mainly in the manner of diffusion in the absence of infection while erosion mechanism in the presence of infection.

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 Poly(-caprolactone)/graphene oxide composite systems: A comparative study on hydrolytic degradation at extreme pH values

2020 ◽  
Vol 10 (6) ◽  
pp. 892-902
Author(s):  
Alberto J. Campillo-Fernández ◽  
Pablo González-Reed ◽  
Ana Vidaurre ◽  
Isabel Castilla-Cortázar
Keyword(s):  
Graphene Oxide ◽  
Degradation Kinetics ◽  
Morphological Changes ◽  
Hydrolytic Degradation ◽  
Degradation Behavior ◽  
Composite Systems ◽  
Ph Values ◽  
Speed Up ◽  
Poly Caprolactone ◽  
Degradation Time

Polycaprolactone/Graphene oxide (PCL/GO) composites are shown to be promising substrates for tissue engineering as their degradation behavior is a key aspect in this type of application. The present paper studies the effect of different GO contents (0.1, 0.2 and 0.5 wt%) of PCL/GO composites on accelerated hydrolytic degradation at extreme pH values. Degradation kinetics at pH 13 is strongly affected by GO content, and speed up at higher percentages. The composite with 0.5 wt% of GO was completely degraded in 72 hours, while degradation at pH 1 presents a different profile and seems to have an induction period that lasts more than 1500 hours. Morphological changes, molecular weight distribution, weight loss, degree of swelling and calorimetric properties were investigated as a function of degradation time. According to the results obtained, the addition of small percentages of GO significantly influences the degradation behavior of the composites acting as degradation modulators.

scholarly journals Investigation of certain varieties of carbopol in ketorolac tromethamine hydrophilic matrix tablet formulations and evaluation of the kinetics of its in vitm release

2002 ◽  
Vol 70 (2) ◽  
pp. 189-198
Author(s):  
Genç Lütfi ◽  
Hegazy Nahed ◽  
Arica Betül
Keyword(s):  
Release Kinetics ◽  
In Vitro Release ◽  
Controlled Drug Release ◽  
Matrix Tablets ◽  
In Vitro Dissolution ◽  
Matrix Tablet ◽  
Compression Technique ◽  
Tablet Formulations ◽  
Kinetics Of

Matrix tablets of ketorolac trometharnine (KT) were prepared by direct compression technique and Carbopol 934, 940 and 1342 have been used as polymers in different concentrations (5-15 % ). For the quality control of tablets; physical tests as crushing strength, diameter-height ratio and fkiability, KT amount assay and in vitro dissolution techniques were performed and dissolution profiles were plotted and evaluated kinetically. The in vitro release kinetics of ten different formulations of KT matrix tablet were studied at pH 1.2 and pH 7.0 using the USP dissolution technique and apparatus with basket assembly. Dissolution results were evaluated kinetically and statistically. According to our results, different types and concentrations of carbopol to tablet formulations may effect in controlled drug release.

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