scholarly journals Characterisation of aptamer-anchored poly(EDMA-co-GMA) monolith for high throughput affinity binding

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Caleb Acquah ◽  
Yi Wei Chan ◽  
Sharadwata Pan ◽  
Lau Sie Yon ◽  
Clarence M. Ongkudon ◽  
...  
Keyword(s):  
Schiff Base ◽  
Md Simulations ◽  
Ionic Concentration ◽  
Scanning Calorimetry ◽  
Ligand Density ◽  
Binding Characteristics ◽  
Degradation Temperature ◽  
Base Process ◽  
Molecular Stability ◽  
Poly Ethylene

Abstract Immobilisation of aptameric ligands on solid stationary supports for effective binding of target molecules requires understanding of the relationship between aptamer-polymer interactions and the conditions governing the mass transfer of the binding process. Herein, key process parameters affecting the molecular anchoring of a thrombin-binding aptamer (TBA) onto polymethacrylate monolith pore surface, and the binding characteristics of the resulting macroporous aptasensor were investigated. Molecular dynamics (MD) simulations of the TBA-thrombin binding indicated enhanced Guanine 4 (G4) structural stability of TBA upon interaction with thrombin in an ionic environment. Fourier-transform infrared spectroscopy and thermogravimetric analyses were used to characterise the available functional groups and thermo-molecular stability of the immobilised polymer generated with Schiff-base activation and immobilisation scheme. The initial degradation temperature of the polymethacrylate stationary support increased with each step of the Schiff-base process: poly(Ethylene glycol Dimethacrylate-co-Glycidyl methacrylate) or poly(EDMA-co-GMA) [196.0 °C (±1.8)]; poly(EDMA-co-GMA)-Ethylenediamine [235.9 °C (±6.1)]; poly(EDMA-co-GMA)-Ethylenediamine-Glutaraldehyde [255.4 °C (±2.7)]; and aptamer-modified monolith [273.7 °C (±2.5)]. These initial temperature increments reflected in the associated endothermic energies were determined with differential scanning calorimetry. The aptameric ligand density obtained after immobilisation was 480 pmol/μL. Increase in pH and ionic concentration affected the surface charge distribution and the binding characteristics of the aptamer-modified disk-monoliths, resulting in the optimum binding pH and ionic concentration of 8.0 and 5 mM Mg2+, respectively. These results are critical in understanding and setting parametric constraints indispensable to develop and enhance the performance of aptasensors.

scholarly journals Thermal properties of MECDP copolyesters

2012 ◽  
Vol 16 (5) ◽  
pp. 1456-1459 ◽  
Author(s):  
Ming-Liang Zhao ◽  
Yuan Liu ◽  
Fa-Xue Li ◽  
Xue-Li Wang ◽  
Yu Gao ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermal Degradation ◽  
Ethylene Glycol ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Poly Ethylene Terephthalate ◽  
Oxygen Condition ◽  
Poly Ethylene ◽  
Temperature Melting

MECDP copolyesters based on poly(ethylene terephthalate) were prepared with sodium-5-sulfo-bis-(hydroxyethyl)-isophthalate and poly(ethylene glycol) units as modifiers. Thermal properties of these copolyesters were characterized by differential scanning calorimetry and thermal gravity analyzer. Experimental results indicated that glass transition temperature, melting temperature and thermal degradation temperature reduced with increasing the poly(ethylene glycol) content. The incorporation of poly(ethylene glycol) increased the flexibility and irregularity of molecular chains which led to lower crystallinity, and bought more ether bonds into molecular chains. Besides, the thermal degradation under oxygen condition happened easily compared to that under nitrogen condition.

Solid-State Grafting of Poly(ethylene glycol) onto Alginic Acid

2014 ◽  
Vol 1060 ◽  
pp. 180-183
Author(s):  
Siti Salimah Mohamad Ismail ◽  
Chan Chin Han ◽  
Tin Wui Wong
Keyword(s):  
Ethylene Glycol ◽  
Alginic Acid ◽  
Carboxyl Group ◽  
Amino Group ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Rate Of Reaction ◽  
Poly Ethylene ◽  
Kinetics Of

Melt reaction of poly (ethylene glycol) and alginic acid (guluronate-rich and mannuronate-rich) was studied. The poly (ethylene glycol) was end-capped with reactive amino group while the sodium alginate was converted to alginic acid before melt reaction. The melt reaction kinetics of poly (ethylene glycol) and alginic acid were monitored by differential scanning calorimetry. The reaction temperatures were ranged between 75 and 96 °C, below the degradation temperature of both parent polymers. The reactive amino group of poly (ethylene glycol) reacted with carboxyl group of alginic acid. The rate of reaction increased with reaction temperature.

scholarly journals Synthesis and Characterization of N-Substituted Polyether-Block-Amide Copolymers

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 773
Author(s):  
Jyun-Yan Ye ◽  
Kuo-Fu Peng ◽  
Yu-Ning Zhang ◽  
Szu-Yuan Huang ◽  
Mong Liang
Keyword(s):  
Titanium Isopropoxide ◽  
Decomposition Temperature ◽  
Phenyl Isocyanate ◽  
Cross Linking ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Melt Polycondensation ◽  
Structural Regularity

A series of N-substituted polyether-block-amide (PEBA-X%) copolymers were prepared by melt polycondensation of nylon-6 prepolymer and polytetramethylene ether glycol at an elevated temperature using titanium isopropoxide as a catalyst. The structure, thermal properties, and crystallinity of PEBA-X% were investigated using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, and thermogravimetric analysis. In general, the crystallinity, melting point, and thermal degradation temperature of PEBA-X% decreased as the incorporation of N-methyl functionalized groups increased, owing to the disruption caused to the structural regularity of the copolymer. However, in N-acetyl functionalized analogues, the crystallinity first dropped and then increased because of a new γ form arrangement that developed in the microstructure. After the cross-linking reaction of the N-methyl-substituted derivative, which has electron-donating characteristics, with poly(4,4′-methylenebis(phenyl isocyanate), the decomposition temperature of the resulting polymer significantly increased, whereas no such improvements could be observed in the case of the electro-withdrawing N-acetyl-substituted derivative, because of the incompleteness of its cross-linking reaction.

scholarly journals Tailoring Atomoxetine Release Rate from DLP 3D-Printed Tablets Using Artificial Neural Networks: Influence of Tablet Thickness and Drug Loading

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 111
Author(s):  
Gordana Stanojević ◽  
Djordje Medarević ◽  
Ivana Adamov ◽  
Nikola Pešić ◽  
Jovana Kovačević ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Release Rate ◽  
Drug Loading ◽  
Prolonged Release ◽  
Cylindrical Shape ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Artificial Neural ◽  
Poly Ethylene

Various three-dimensional printing (3DP) technologies have been investigated so far in relation to their potential to produce customizable medicines and medical devices. The aim of this study was to examine the possibility of tailoring drug release rates from immediate to prolonged release by varying the tablet thickness and the drug loading, as well as to develop artificial neural network (ANN) predictive models for atomoxetine (ATH) release rate from DLP 3D-printed tablets. Photoreactive mixtures were comprised of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) 400 in a constant ratio of 3:1, water, photoinitiator and ATH as a model drug whose content was varied from 5% to 20% (w/w). Designed 3D models of cylindrical shape tablets were of constant diameter, but different thickness. A series of tablets with doses ranging from 2.06 mg to 37.48 mg, exhibiting immediate- and modified-release profiles were successfully fabricated, confirming the potential of this technology in manufacturing dosage forms on demand, with the possibility to adjust the dose and release behavior by varying drug loading and dimensions of tablets. DSC (differential scanning calorimetry), XRPD (X-ray powder diffraction) and microscopic analysis showed that ATH remained in a crystalline form in tablets, while FTIR spectroscopy confirmed that no interactions occurred between ATH and polymers.

scholarly journals Comparative Study of Structural Changes of Polylactide and Poly(ethylene terephthalate) in the Presence of Trichoderma viride

2021 ◽  
Vol 22 (7) ◽  
pp. 3491
Author(s):  
Grażyna B. Dąbrowska ◽  
Zuzanna Garstecka ◽  
Ewa Olewnik-Kruszkowska ◽  
Grażyna Szczepańska ◽  
Maciej Ostrowski ◽  
...  
Keyword(s):  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Molecular Mechanisms ◽  
Blot Hybridization ◽  
Trichoderma Viride ◽  
Cost Effective ◽  
Plastic Pollution ◽  
Scanning Calorimetry ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Plastic pollution is one of the crucial global challenges nowadays, and biodegradation is a promising approach to manage plastic waste in an environment-friendly and cost-effective way. In this study we identified the strain of fungus Trichoderma viride GZ1, which was characterized by particularly high pectinolytic activity. Using differential scanning calorimetry, Fourier-transform infrared spectroscopy techniques, and viscosity measurements we showed that three-month incubation of polylactide and polyethylene terephthalate in the presence of the fungus lead to significant changes of the surface of polylactide. Further, to gain insight into molecular mechanisms underneath the biodegradation process, western blot hybridization was used to show that in the presence of poly(ethylene terephthalate) (PET) in laboratory conditions the fungus produced hydrophobin proteins. The mycelium adhered to the plastic surface, which was confirmed by scanning electron microscopy, possibly due to the presence of hydrophobins. Further, using atomic force microscopy we demonstrated for the first time the formation of hydrophobin film on the surface of aliphatic polylactide (PLA) and PET by T. viride GZ1. This is the first stage of research that will be continued under environmental conditions, potentially leading to a practical application.

scholarly journals Identification of LDPE Grades Focusing on Specific CH2 Raman Vibration Modes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Richard Jumeau ◽  
Patrice Bourson ◽  
Michel Ferriol ◽  
François Lahure ◽  
Marc Ponçot ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Vibrational Spectroscopy ◽  
Phenomenological Model ◽  
Low Density ◽  
Vibration Modes ◽  
Scanning Calorimetry ◽  
Lamella Thickness ◽  
Poly Ethylene

The possibilities of applications of vibrational spectroscopy techniques (Raman spectroscopy) in the analysis and characterization of polymers are more and more used and accurate. In this paper, our purpose is to characterize Low Density Poly(Ethylene) (LDPE) grades by Raman spectroscopy and in particular with CH2 Raman vibration modes. With temperature measurements, we determine different amorphous and crystalline Raman assignments. From these results and on the basis of the evolution of CH2 bending Raman vibration modes, we develop a phenomenological model in correlation with Differential Scanning Calorimetry and in particular with crystalline lamella thickness determination.

scholarly journals Poly(δ-valerolactone)/Poly(ethylene-co-vinylalcohol)/β-Tricalcium Phosphate Composite as Scaffolds: Preparation, Properties, and In Vitro Amoxicillin Release

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 46
Author(s):  
Mohammed Badwelan ◽  
Mohammed Alkindi ◽  
Osama Alghamdi ◽  
Waseem Sharaf Saeed ◽  
Abdel-Basit Al-Odayni ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Tricalcium Phosphate ◽  
Drug Carrier ◽  
Human Mesenchymal Stem Cells ◽  
In Vitro Study ◽  
Micro Computed Tomography ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Poly Ethylene

Two poly(δ-valerolactone)/poly(ethylene-co-vinylalcohol)/β-tricalcium phosphate (PEVAL/PDVAL/β-TCP) composites containing an equal ratio of polymer and filled with 50 and 70 wt% of β-TCP microparticles were prepared by the solvent casting method. Interconnected pores were realized using the salt leached technique, and the porosity of the resulted composites was evaluated by the scanning electron microscopy (SEM) method. The homogeneity of the hybrid materials was investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The prepared materials’ SEM images showed interconnected micropores that respond to the conditions required to allow their uses as scaffolds. The porosity of each scaffold was determined from micro computed tomography (micro-CT) data, and the analysis of the mechanical properties of the prepared materials was studied through the stress-strain compressive test. The proliferation test results used human mesenchymal stem cells (MSCs) to grow and proliferate on the different types of prepared materials, reflecting that the hybrid materials were non-toxic and could be biologically acceptable scaffolds. The antibacterial activity test revealed that incorporation of amoxicillin in the specimens could inhibit the bacterial growth of S. aureus. The in vitro study of the release of amoxicillin from the PEVAL/PDVAL/amoxicillin and PEVAL/PDVAL/β-TCP/amoxicillin drug carrier systems in pH media 7.4, during eight days, gave promising results, and the antibiotic diffusion in these scaffolds obeys the Fickian model.

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