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 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 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.

scholarly journals Novel In Vivo-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered Gluconacetobacter xylinus

2010 ◽  
Vol 76 (18) ◽  
pp. 6257-6265 ◽  
Author(s):  
Vikas Yadav ◽  
Bruce J. Paniliatis ◽  
Hai Shi ◽  
Kyongbum Lee ◽  
Peggy Cebe ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
De Novo ◽  
Biomass Conversion ◽  
Gluconacetobacter Xylinus ◽  
The Poor ◽  
Wide Range ◽  
Potential Applications ◽  
Rapid Hydrolysis

ABSTRACT Despite excellent biocompatibility and mechanical properties, the poor in vitro and in vivo degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce N-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during de novo synthesis from Gluconacetobacter xylinus. The cellulose produced from these engineered cells (modified bacterial cellulose [MBC]) was evaluated and compared with cellulose produced from normal cells (bacterial cellulose [BC]). High GlcNAc content and lower crystallinity in MBC compared to BC make this a multifunctional bioengineered polymer susceptible to lysozyme, an enzyme widespread in the human body, and to rapid hydrolysis by cellulase, an enzyme commonly used in biomass conversion. Degradability in vivo was demonstrated in subcutaneous implants in mice, where modified cellulose was completely degraded within 20 days. We provide a new route toward the production of a family of tailorable modified cellulosic biopolymers that overcome the longstanding limitation associated with the poor degradability of cellulose for a wide range of potential applications.

Effect of selective oxidation of bacterial cellulose on degradability in phosphate buffer solution and their affinity for epidermal cell attachment

RSC Advances ◽  
2014 ◽  
Vol 4 (105) ◽  
pp. 60749-60756 ◽  
Author(s):  
Xiangning Shi ◽  
Qiuyan Cui ◽  
Yudong Zheng ◽  
Shuai Peng ◽  
Guojie Wang ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Mass Loss ◽  
Bacterial Cellulose ◽  
Selective Oxidation ◽  
Phosphate Buffer ◽  
Degradation Rate ◽  
Cell Attachment ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Cell Adhesion And Proliferation

Oxidized bacterial cellulose showed the 3D nano-fibrils structure of BC. The mass loss and degradation rate of OBC were much higher than those of BC. When immersed in PBS, OBC degraded gradually. Cell-adhesion and proliferation studies revealed that OBC had excellent cellular affinity.

scholarly journals Encapsulation of Polyphenols from Lycium barbarum Leaves into Liposomes as a Strategy to Improve Their Delivery

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1938
Author(s):  
Ramona-Daniela Păvăloiu ◽  
Fawzia Sha’at ◽  
Georgeta Neagu ◽  
Mihaela Deaconu ◽  
Corina Bubueanu ◽  
...  
Keyword(s):  
Particle Size ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Entrapment Efficiency ◽  
Cytoprotective Effect ◽  
Buffer Solution ◽  
Lycium Barbarum ◽  
Burst Effect ◽  
Pharmaceutical Applications

This study is focused on the encapsulation of polyphenols from Lycium barbarum leaves into liposomes as a strategy to improve their delivery. Liposomes loaded with Lycium barbarum leaves extract were obtained and characterized for particle size, polydispersity, entrapment efficiency, and stability. Liposomes presented entrapment efficiency higher than 75%, nanometric particle size, narrow polydispersity, and good stability over three months at 4 °C. The liposomes containing Lycium barbarum offered a slower release of polyphenols with attenuated burst effect compared with the dissolution of free Lycium barbarum extract in phosphate buffer solution at pH 7.4. Moreover, an in vitro pretreatment of 24 h with loaded liposomes showed a cytoprotective effect against H2O2-induced cytotoxicity on L-929 mouse fibroblasts cells. These preliminary findings imply that liposomes could be successfully employed as carriers for polyphenols in pharmaceutical applications.

Preparation and Characterization of Danazol Nanoparticles for Dissolution Improvement

2018 ◽  
Vol 9 (SPL1) ◽  
Author(s):  
Luma Safa el-din Al-Hassnaui
Keyword(s):  
Particle Size ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Amorphous State ◽  
Volume Ratio ◽  
In Vitro Dissolution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Freeze Dried

Danazol is a synthetic steroid used for endometriosis treatment, haslow bioavailability as it is practically insoluble in water. This study has been carried out to prepare and characterize danazol nanoparticles by nanoprecipitation method at a different polymer to drug ratios of 0.5:1,1:1,2:1 and 3:1 using different polymers of CMC-30 and various grades of HPMC and PVP,as stabilizers. Variables that might affect the particle size as polymer type,polymer to drug ratio,temperature of precipitation,addition rate of danazol solution,volume ratio,time of stirring,concentrationof drug,have been investigated. The particle size of the prepared formulas has been in the nano-sized except those using CMC and the best formula has beenF20 at a polymer to drug ratio of0.5:1 which has given the smallest particle sizeof 33nm.The investigations of the drug–stabilizer compatibility havebeen studied by FTIR and DSC,crystalline state by XRD,size,and shape of nanoparticles by FESEM and the results showed that there has been no interaction between the danazol and stabilizer and there has been a partial conversion of danazol from crystalline to an amorphous state with a size below 100nm. Most of the studied factors havebeen found affect the particle size of the nanoparticles.The Entrapment efficiency has been (91.3% ± 0.4) in the (F20). The solubility study revealed that 6.75,4.97 and 5.1 folds increased of solubility of danazol for nanoparticles than that for raw in distilled water,0.1N HCl and in phosphate buffer of pH 6.8.The simple capsule has been prepared by incorporation of freeze-dried of F20 with lactose as a filler and the in vitro dissolution study has been conducted using 0.1N HCl (pH 1.2) with 2% w/v Brij-35,phosphate buffer solution(pH 6.8) with 2% w/v Brij-35as dissolution media. Within 30 minutes,100% of the danazol has been released from the nanoparticle capsule in both dissolution media compared to the raw and physical blend capsules as controls havebeen nearly complete in 120 minutes.One can conclude that Antisolvent method is an easy,efficient method to prepare danazol nanoparticles with an intense effect on solubility and faster in vitro dissolution rate than raw drug and its physical blend with stabilizer.

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.

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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