scholarly journals Effects of Magnesium Oxide (MgO) Shapes on In Vitro and In Vivo Degradation Behaviors of PLA/MgO Composites in Long Term

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1074 ◽  
Author(s):  
Yun Zhao ◽  
Hui Liang ◽  
Shiqiang Zhang ◽  
Shengwei Qu ◽  
Yue Jiang ◽  
...  
Keyword(s):  
Magnesium Oxide ◽  
Ph Value ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Biomedical Material ◽  
Degradation Behaviors ◽  
In Vivo Degradation

Biodegradable devices for medical applications should be with an appropriate degradation rate for satisfying the various requirements of bone healing. In this study, composite materials of polylactic acid (PLA)/stearic acid-modified magnesium oxide (MgO) with a 1 wt% were prepared through blending extrusion, and the effects of the MgO shapes on the composites’ properties in in vitro and in vivo degradation were investigated. The results showed that the long-term degradation behaviors of the composite samples depended significantly on the filler shape. The degradation of the composites is accelerated by the increase in the water uptake rate of the PLA matrix and the composite containing the MgO nanoparticles was influenced more severely by the enhanced hydrophilicity. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO through the neutralization of the acidic product of the PLA degradation. In addition, the improvement of the in vivo degrading process of the composite illustrated that the PLA/MgO materials can effectively regulate the degradation of the PLA matrix as well as raise its bioactivity, indicating the composites for utilization as a biomedical material matching the different requirements for bone-related repair.

scholarly journals In Vitro Structural Changes of Nano-Bacterial Cellulose Immersed in Phosphate Buffer Solution

2011 ◽  
Vol 10 ◽  
pp. 55-66 ◽  
Author(s):  
Yan Mei Chen ◽  
Ting Fei Xi ◽  
Yu Feng Zheng ◽  
Liang Zhou ◽  
Yi Zao Wan
Keyword(s):  
Bacterial Cellulose ◽  
Phosphate Buffer ◽  
Structural Changes ◽  
Ph Value ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Potential Applications ◽  
Scaffold Materials

Nano-bacterial cellulose (nBC), secreted by Acetobacter xylinum, is expected to have potential applications in tissue engineering. In this paper, the in-vitro degradation performance and the corresponding mechanism of nBC immersed in phosphate buffer solution (PBS) for different time periods was investigated. The pH value variation of solution, material degradation, and the swelling and structural changes of nBC was analysed successively. The results indicate that water molecules attack the exposed nBC fibrils, weakening the bonding strength of inter- and intra-molecular chains and disconnecting partial C-O-C bonds. The disconnection of C-O-C bonds is considered the primary reason for the degradation of nBC large molecular chains after nBC is immersed in PBS. The present work is instructive for controlling the in-vivo degradation performance of nBC acting as bone tissue engineered scaffold materials.

scholarly journals Fabrication, Crystalline Behavior, Mechanical Property and In-Vivo Degradation of Poly(l–lactide) (PLLA)–Magnesium Oxide Whiskers (MgO) Nano Composites Prepared by In-Situ Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1123 ◽  
Author(s):  
Hui Liang ◽  
Yun Zhao ◽  
Jinjun Yang ◽  
Xiao Li ◽  
Xiaoxian Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Oxide ◽  
Bone Repair ◽  
In Situ Polymerization ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Biomedical Material ◽  
In Vivo Degradation

The present work focuses on the preparation of poly(l–lactide)–magnesium oxide whiskers (PLLA–MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA–MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA–MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA–MgO composite to serve as a biomedical material for bone-related repair.

scholarly journals Performance of Polyester-Based Electrospun Scaffolds under In Vitro Hydrolytic Conditions: From Short-Term to Long-Term Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 786 ◽  
Author(s):  
Oscar Gil-Castell ◽  
José David Badia ◽  
Jordi Bou ◽  
Amparo Ribes-Greus
Keyword(s):  
Molar Mass ◽  
Pure Water ◽  
Phosphate Buffer Solution ◽  
Short Term ◽  
Buffer Solution ◽  
Electrospun Scaffolds ◽  
The Stability ◽  
Short Time

The evaluation of the performance of polyesters under in vitro physiologic conditions is essential to design scaffolds with an adequate lifespan for a given application. In this line, the degradation-durability patterns of poly(lactide-co-glycolide) (PLGA), polydioxanone (PDO), polycaprolactone (PCL) and polyhydroxybutyrate (PHB) scaffolds were monitored and compared giving, as a result, a basis for the specific design of scaffolds from short-term to long-term applications. For this purpose, they were immersed in ultra-pure water and phosphate buffer solution (PBS) at 37 °C. The scaffolds for short-time applications were PLGA and PDO, in which the molar mass diminished down to 20% in a 20–30 days lifespan. While PDO developed crystallinity that prevented the geometry of the fibres, those of PLGA coalesced and collapsed. The scaffolds for long-term applications were PCL and PHB, in which the molar mass followed a progressive decrease, reaching values of 10% for PCL and almost 50% for PHB after 650 days of immersion. This resistant pattern was mainly ascribed to the stability of the crystalline domains of the fibres, in which the diameters remained almost unaffected. From the perspective of an adequate balance between the durability and degradation, this study may serve technologists as a reference point to design polyester-based scaffolds for biomedical applications.

scholarly journals In vitro dissolution and in vivo gamma scintigraphic evaluation of press-coated salbutamol sulfate tablets

2013 ◽  
Vol 63 (4) ◽  
pp. 545-551 ◽  
Author(s):  
Wei Li ◽  
Cai-Hong Shi ◽  
Yi-Ling Sheng ◽  
Ping Cui ◽  
Yu-Qing Zhao ◽  
...  
Keyword(s):  
In Vitro Release ◽  
Phosphate Buffer Solution ◽  
Gamma Scintigraphy ◽  
In Vitro Dissolution ◽  
Salbutamol Sulfate ◽  
Buffer Solution ◽  
Delayed Release ◽  
Vitro Release

Abstract The aim of this study was to investigate the in vitro and in vivo performance of salbutamol sulfate press-coated tablets for delayed release. The in vitro release behavior of press-coated tablets with the outer layer of PEG 6000/ Eudragit S100 blends (2:1) in pH 1.2 (0.1 mol L-1 HCl) and then pH 6.8 buffer solution was examined. Morphological change of the press-coated tablet during in vitro release was recorded with a digital camera. Release of salbutamol sulfate from press-coated tablets was less than 5 % before 3 h and was completed after 8 h in pH 6.8 phosphate buffer solution. In vivo gamma scintigraphy study carried out on healthy men indicated that the designed system released the drug in lower parts of the GI tract after a lag time of 5 hours. The results showed the capability of the system of achieving delayed release of the drug in both in vitro and in vivo gamma scintigraphy studies.

In vitro and in vivo degradation behaviors of synthetic absorbable bicomponent monofilament suture prepared with poly(p-dioxanone) and its copolymer

2007 ◽  
Vol 92 (4) ◽  
pp. 667-674 ◽  
Author(s):  
Jung Nam Im ◽  
Jeong Kyung Kim ◽  
Hyun-Kyoon Kim ◽  
Chang Hoon In ◽  
Kuen Yong Lee ◽  
...  
Keyword(s):  
Monofilament Suture ◽  
Degradation Behaviors ◽  
In Vivo Degradation

scholarly journals The Degradation Properties of MgO Whiskers/PLLA Composite In Vitro

2018 ◽  
Vol 19 (9) ◽  
pp. 2740 ◽  
Author(s):  
Yun Zhao ◽  
Bei Liu ◽  
Hongwei Bi ◽  
Jinjun Yang ◽  
Wei Li ◽  
...  
Keyword(s):  
Ph Value ◽  
Composite Films ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
In Vitro Degradation ◽  
Final Weight ◽  
Cell Affinity ◽  
Degradation Properties ◽  
Composite Samples

In this study, composite films of stearic acid–modified magnesium oxide whiskers (Sa–w-MgO)/poly-l-lactic acid (PLLA) were prepared through solution casting, and the in vitro degradation properties and cytocompatibility of the composites with different whisker contents were investigated. The results showed that the degradation behavior of the composite samples depended significantly on the whisker content, and the degradation rate increased with the addition of MgO content. Furthermore, the degradation of the composites with higher contents of whiskers was influenced more severely by the hydrophilicity and pH value, leading to more final weight loss, but the decomposition rate decreased gradually. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO whiskers through neutralization of the acidic product of PLLA degradation. The cytocompatibility of the composites also increased remarkably, as determined from the cell viability results, and was higher than that of PLLA at the chosen whisker content. This was beneficial for the cell affinity of the material, as it notably led to an enhanced biocompatibility of the PLLA, in favor of promoting cell proliferation, which significantly improved its bioactivity, as well.

scholarly journals In Vitro Activity Assays of Sputtered HAp Coatings with SiC Addition in Various Simulated Biological Fluids

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 389 ◽  
Author(s):  
Alina Vlădescu ◽  
Anca Pârâu ◽  
Iulian Pană ◽  
Cosmin M. Cotruț ◽  
Lidia R. Constantin ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Electrochemical Behavior ◽  
Biological Fluids ◽  
Phosphate Buffer Solution ◽  
Implantable Devices ◽  
Buffer Solution ◽  
The Media ◽  
Tissue Interface

Considering the requirements of medical implantable devices, it is pointed out that biomaterials should play a more sophisticated, longer-term role in the customization and optimization of the material–tissue interface in order to ensure the best long-term clinical outcomes. The aim of this contribution was to assess the performance of silicon carbide–hydroxyapatite in various simulated biological fluids (Dulbecco’s modified Eagle’s medium (DMEM), simulated body fluid (SBF), and phosphate buffer solution (PBS)) through immersion assays for 21 days at 37 ± 0.5 °C and to evaluate the electrochemical behavior. The coatings were prepared on Ti6Al4V alloy substrates by magnetron sputtering method using two cathodes made of hydroxyapatite and silicon carbide (SiC). After immersion assays the coating’s surface was analyzed in terms of morphology, chemical and phase composition, and chemical bonds. According to the electrochemical behavior in the media investigated at 37 ± 0.5 °C, SiC addition inhibits the dissolution of the hydroxyapatite in DMEM acellular media. Furthermore, after adding SiC, the slow degradation of hydroxyapatite in PBS and SBF media as well as biomineralization in DMEM were observed.

Demonstration of Z-RNA in the Dog Eye Lens Epithelium (Germinative Zone)

1998 ◽  
Vol 4 (S2) ◽  
pp. 1108-1109
Author(s):  
C.E. Gagna ◽  
J.H. Chen ◽  
H.R. Kuo ◽  
W.C. Lambert
Keyword(s):  
Cellular Localization ◽  
Cultured Cells ◽  
Polyclonal Antibodies ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Immunogold Staining ◽  
Z Dna

The purpose of this scientific investigation was to determine the presence and specific cellular localization of left-handed Z-RNA, within germinative zone (GZ) epithelium of the lens (Fig. 1), using anti-Z-RNA IgG polyclonal antibodies. Right-handed B-DNA has the ability to adopt the Z-DNA conformation in vitro (Sinden, 1994). Right-handed A-RNA can be transformed into Z-RNA under specific conditions (Hall et al., 1984), and Z-RNA has been identified in cultured cells (Zarling et al., 1990). Strong evidence supports the idea of Z-DNA in vivo (Sinden, 1994). Removal of proteins by fixatives can induce supercoiling which stabilizes Z-DNA (Sinden, 1994).Anti-Z-RNA antibodies were produced in rabbits immunized with injections of Z-RNA: brominated-poly[ribosomal(G-C)]. For light microscopy, immunohistochemical studies (ABC method), normal dog lens tissues (1 yr old) were fixed in Carnoy's, embedded in paraffin and sectioned 2 μm thick. For electron microscopy (immunogold staining), pieces of epithelium from the GZ of normal dog lens (1 yr old) were fixed with 5% glutaraldehyde in 0.05 M phosphate buffer solution, pH 7.3.

Polyamidoamine dendrimer and dextran conjugates: preparation, characterization, and in vitro and in vivo evaluation

2010 ◽  
Vol 64 (5) ◽  
Author(s):  
Prabhat Shrivastava ◽  
Royana Singh ◽  
Sushant Shrivastava
Keyword(s):  
Phosphate Buffer Solution ◽  
Pamam Dendrimer ◽  
Simulated Gastric Fluid ◽  
Ulcer Index ◽  
Buffer Solution ◽  
In Vivo Evaluation ◽  
Standard Drug ◽  
Dextran 40

AbstractAmide and ester conjugates of aceclofenac with polyamidoamine (PAMAM-G0) dendrimer zero generation and dextran (40 kDa) polymeric carrier, respectively, are presented. The prepared conjugates were characterized by UV, TLC, HPLC, IR, and 1H NMR spectroscopy. The average degrees of substitution of amide and ester conjugates were determined and found to be (12.5 ± 0.24) % and (7.5 ± 0.25) %, respectively. The in vitro hydrolysis studies showed that dextran ester conjugate hydrolyzed faster in a phosphate buffer solution of pH 9.0 as compared to PAMAM dendrimer G0 amide conjugate, and followed the first order kinetics. No amount of the drug was regenerated at pH 1.2 in simulated gastric fluid. The dextran conjugate showed short half-life as compared to the PAMAM dendrimer conjugate. Anti-inflammatory and analgesic activities of the dendrimer conjugate were found to be similar to those of the standard drug. Results of chronic ulceroginic activity showed deep ulceration and high ulcer index for aceclofenac, whereas lower ulcer index was found for the PAMAM dendrimer and dextran (40 kDa) conjugates. Experimental data suggest that PAMAM dendrimer and dextran (40 kDa) can be used as carriers for the sustained delivery of aceclofenac along with a remarkable reduction in gastrointestinal toxicity.

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