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Biomaterials science and tissue engineering : principles and methods
\"Provides an encyclopedic coverage of biomaterials science which, at the same time, has enough to interest the biomedical scientists and engineers\"-- Provided by publisher.
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Benzodithiophene bearing conjugated polymer-based surface anchoring for sensitive electrochemical glucose detection
An amino-functionalized, conjugated polymer (P(BDBT)) modified glassy carbon electrode (GCE) was employed as an immobilization platform for glucose oxidase (GOx) enzyme to assemble a novel glucose biosensor. Amino groups available on the polymer backbone served as bioconjugation sites for GOx via glutaraldehyde (GA). The biosensor response to the reduction in oxygen amount because of the enzyme reaction was monitored at -0.7 V potential versus Ag/AgCl. The biosensor displayed a broad linear range between 0.1-1.0 mM glucose with a detection limit of 0.17 mM. The values of the apparent Michaelis-Menten constant (...) and sensitivity were determined as 1.74 mM, and 28.17 μA/(mM·cm2), respectively. GOx immobilized P(BDBT) film displayed high stability, selectivity, and reproducibility. Cyclic voltammetry (CV) and Scanning electron microscopy (SEM) techniques were utilized for the characterization of surface modifications. The fabricated biosensor was adept at determining the amount of glucose in a commercial beverage. The simple electrochemical method for the construction of P(BDBT)/GOx biosensors could pave the way to new perspectives in developing profitable biosensors.
Journal Article
Synthesis and characterization of isophorondiamine based epoxy hardeners from aminolysis of PET
The solvolysis of poly(ethylene-terephthalate) (PET) is one of the most researched areas in chemical recycling. In this study PET aminolysis with isophorondiamine has been done - in opposition to recent trends - without excess reagent and the raw reaction product was further used without purification. The aminolysis product was thoroughly characterized with nuclear magnetic resonance (NMR) spectroscopy. Isophoronediamine was used as a solvent to prepare amine crosslinker solutions for epoxy resins. The effect of the concentration on the cross-linking reaction and thermomechanical properties were investigated. The curing reaction was found to be significantly accelerated by the presence of the aminolysis product. Both the ethylene-glycol and the terephthal-amide-diamines have a catalytic effect on the reaction. The glass transition temperature decreased with increasing concentrations of the cross-linker solutions due to the decreasing cross-link density. Thus, raw aminolysis products can be utilized for epoxy curing and are advantageous in modifying slower curing cycloaliphatic cross linker systems.
Journal Article
Molecular Engineering‐Boosted High‐Performance AIE Sonosensitizer for Cancer Sonodynamic‐Augmented Immunotherapy
Immunogenic cell death (ICD) has been demonstrated as a reliable approach to improve therapeutic effect in cancer treatment by triggering antitumor immunity. However, the trigger of ICD on the basis of chemotherapy and phototherapy meets the obstacles of serious side effect and poor penetration ability, which seriously impedes the therapeutic effect. The development of sonodynamic immunotherapy with the evoking of ICD presents high promise for cancer treatment with high efficacy. Herein, high performance aggregation‐induced emission (AIE) sonosensitizer is constructed on the basis of the engineering structure modulation for sonodynamic‐augmented immunotherapy. By regulating the intermolecular interaction and pull‐push electronic effect, sonosensitizer bearing AIE feature and amplified sono‐sensitizing effect is developed. In addition, in vitro observation demonstrated that thiolate‐substituted segment incorporation endows the molecules with enhanced cellular uptake efficiency and improved tumor cell eradication ability. More importantly, the developed sonosensitizer could efficiently evoke ICD upon the trigger of ultrasound, which allows for the efficient tumor eradication both at cellular level and in solid tumor. The inhibition of primary tumor and further boost systemic immunity response with the complete elimination toward the distant tumor is achieved. The investigation highlights the promise of utilizing AIE sonosensitizers in sonodynamic immunotherapy to conquer the current limitation of immunotherapy in solid tumor treatment. The development of sonodynamic immunotherapy with the evoking of immunogenic cell death presents high promise for cancer treatment in biosafe and penetrated manner. Based on engineering structure modulation by regulating intermolecular interaction and push‐pull electronic effect, high performance aggregation‐induced emission (AIE) sonosensitizer with accelerated cellular uptake ability and improved ROS generation effect is constructed for sonodynamic‐augmented immunotherapy, allowing for complete elimination of both primary and distant tumor.
Journal Article
Enzyme-catalyzed amine-functionalization of poly(ethylene-glycol)
This paper presents a new method for the amine-functionalization of poly(ethylene glycol) (PEG) of Mn = 2050 g/mol via Candida antarctica lipase B (CALB)-catalyzed esterification of tert-butyloxycarbonyl (tBOC)-protected β-Alanine and L-Alanine. NMR showed full conversion for protected β-Alanine, and MALDI-ToF demonstrated the purity of the product. After deprotection, the desired diamine-functionalized PEG was obtained. Protected L-Alanine did not reach full conversion by NMR, likely due to the steric hindrance of its methyl side group.
Journal Article
Anionic ring-opening polymerization of isobutylene oxide initiated with potassium salts activated by 18-crown-6: Determination of mechanism and characterization of polyether monols and diols
Various potassium salts, i.e., KOH, HOC3H6OC3H6OK, CH3OK, i-PrOK, t-BuOK, CbK, and (Me3Si)2NK activated by 18-crown-6 appeared to be active initiators of first anionic polymerization of isobutylene oxide. The processes were performed in mild conditions, i.e., tetrahydrofuran solution at room temperature under normal pressure. The polymers obtained are polyether-monols or -diols also containing macromolecules with starting groups having double bonds (12.5- 46.6 mol%). It was stated that polymer unsaturation results not only from chain transfer reaction to monomer but mainly from deprotonation of monomer by an initiator, which behaves in the polymerizations as nucleophilic bases. In all systems, isomerization of the double bonds is also observed. Most of the obtained polymers are crystalline, insoluble materials with crystalline content up to 52.47% for a derived sample with potassium i-propoxide as initiator. The proneness of the polyisobutylene oxide to form crystal-type package is influenced by the average molar mass of the polymers. They are bimodal with Mn = 400-1300 (Mcalc = 1440) and very low dispersities (Mw/Mn = 1.01-1.12). 13C NMR, MALDI-TOF, FTIR, SEC, XRD, and DSC techniques were used for polymers analysis. A mechanism of the processes studied was proposed.
Journal Article
Poly(1,4-cyclohexanedimethylene 2,6-naphthalate) polyester with high melting point: Effect of different synthesis methods on molecular weight and properties
In the current manuscript, a new approach for the synthesis of poly(1,4- cyclohexanedimethylene 2,6-naphthalate) (PCHDMN) derived from dimethyl 2,6-naphthalenedicarboxylate (2,6-DMN) and 1,4-Cyclohexanedimethanol (CHDM) via melt polycondensation method is introduced. The effect of three different synthesis pathways, polycondensation time and temperature on polyesters molecular weight increase has been investigated. All of the prepared samples were characterized measuring their intrinsic viscosity (IV), thermal properties and morphology with differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), respectively. The results demonstrated the effectiveness of the synthesis pathway proposed for the preparation of PCHDMN, resulting in high molecular weight (IV value around 0.5 dL/g) and much shorter reaction time. Melt polycondensation temperatures above melting point of polyester should be avoided to be used due to the decomposition of polyester. This was proved by thermogravimetric analysis (TGA) and Pyrolysis-gas chromatography-mass spectroscopy analysis (Py-GC/MS).
Journal Article
Synthesis and characterization of polyacrylonitrile-grafted copolymers based on poly(vinylidene fluoride)
Grafted poly(vinylidene fluoride) (PVDF)-based copolymers attract great attention due to their tunable ferroelectric and dielectric characteristics, which gives great perspectives for electronic applications. In this work, two strategies for poly-acrylonitrile-grafted PVDF-based copolymers synthesis, namely single electron transfer radical polymerization (SET-LRP) and photoinduced Cu(II)-mediated reversible deactivation radical polymerization (RDRP) were investigated, their advantages and shortcomings are discussed. Using these methods two series of poly(vinylidene fluoride-co-chlorotrifluoroethylene)-grafted-polyacrylonitrile p(VDF-co-CTFE)-g-PAN and poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroeth-ylene)-grafted-polyacrylonitrile p(VDF-co-TrFE-co-CTFE)-g-PAN with different PAN content were prepared. Important characteristics of the grafted PVDF-based copolymers such as phase behavior, thermal stability, and dielectric properties were investigated, and impacts of the macromolecular backbone type, as well as the content of grafted PAN on these prop-erties, are discussed. It was shown that PAN incorporation leads to significant dielectric properties change since the dielectric permittivity of PAN-grafted copolymers is twice higher in comparison to the pristine copolymers. The crucial impact of PAN grafting onto PVDF-based copolymers backbone on their phase, thermal and dielectric behavior is demonstrated.
Journal Article
Uncatalyzed urethane forming reaction of 1,3-xylylene diisocyanate with aliphatic alcohols of varying chain lengths and polyols
In this article, we report a detailed study on the kinetics of the reaction of 1,3-xylylene diisocyanate (1,3-XDI) with alcohols of varying alkyl chain lengths and with low molecular weight polyols such as monomethoxylated polyethylene glycol (mPEG) and polytetrahydrofuran (PTHF) in toluene, in the absence of a catalyst. It was found that the pseudo-firstorder rate coefficient increased with the increasing alkyl chain length (k1,app was found to be 0.0166 and 0.0341 min-1 for 1-propanol and 1-hexanol, respectively) and the reactivities of the 1,3-xylyene diisocyanate towards the alcohols and polyols are between those of the aromatic and alkyl isocyanates. The activation energies were also determined and were found to vary from 25.6 to 38.6 kJ/mol (from 1-propanol to 1-hexanol). According to further kinetic studies, the rate coefficients k1>app and k2,app for the reaction of 1,3-XDI with PTHF were determined to be (1.13±0.01)-10-2 and (1.28±0.01)-10-2 min-1, respectively. It was also found that the rate constants did not depend significantly on the length of the polymer chain. ever, lower rate coefficients were obtained for the 1,3-XDI-mPEG reaction (k1,app = (2.64±0.03)-10-3 min-1 and k2,app = (2.45±0.03)-10-3 min-1). Besides, the dependence of the pseudo-first-order rate coefficient on the concentration of the alcohols was also studied, and based on these findings a reaction mechanism is proposed.
Journal Article