Nauka prawa finansowego po I dekadzie XXI wieku

Księga pamiątkowa dedykowana profesorowi Apoloniuszowi Kosteckiem

Manufacturing of substitutes for spongy bone with increased absorbability

Composite scaffolds with increased hydrophilicity were prepared for cancellous bone regeneration by the freeze-extraction method. As a construction material, a poly–L–lactide (PLLA) was applied. As a hydrophilic, modifying agent a methacrylic acid copolymer, trade name Eudragit, was used. Apreliminary investigation and optimization of the processwere performed. For the obtained scaffolds, regression equations determining the effect of: EudragitE100/PLLA weight ratio; volume ratio of methanol (porophore)/PLLA solution in dioxane on interconnected porosity and mass absorbability of obtained implants were calculated

Biomimetic scaffolds based on chitosan in bone regeneration. A review

Chitosan (CS) is a polysaccharide readily used in tissue engineering due to its properties: similarity to the glycosaminoglycans present in the body, biocompatibility, non-toxicity, antibacterial character and owing to the fact that its degradation that may occur under the influence of human enzymes generates non-toxic products. Applications in tissue engineering include using CS to produce artificial scaffolds for bone regeneration that provide an attachment site for cells during regeneration processes. Chitosan can be used to prepare scaffolds exclusively from this polysaccharide, composites or polyelectrolyte complexes. A popular solution for improving the surface properties and, as a result enhancing cell-biomaterial interactions, is to coat the scaffold with layers of chitosan. The article focuses on a polysaccharide of natural origin – chitosan (CS) and its application in scaffolds in tissue engineering. The last part of the review focuses on bone tissue and interactions between cells and chitosan after implantation of a scaffold and how chitosan’s structure affects bone cell adhesion and life processes

Optimisation of Glycerol and Itaconic Anhydride Polycondensation

Glycerol polyesters have recently become objects of interest in tissue engineering. Barely known so far is poly(glycerol itaconate) (PGItc), a biocompatible, biodegradable polyester. Due to the presence of a C=C electron-acceptor moiety, it is possible to post-modify the product by Michael additions to change the properties of PGItc. Thus, using PGItc as one of the elements of cellular scaffold crosslinked in situ for bone tissue regeneration seems to be a very attractive yet unexplored solution. This work aims to optimize the synthesis of PGItc to obtain derivatives with a double bond in the side chain with the highest conversion rates. The experiments were performed with itaconic anhydride and glycerol using mathematical planning of experiments according to the Box-Behnken plan without solvent and catalyst. The input variables of the process were the ratio of the OH/COOH, temperature, and reaction time. The optimised output variables were: the degree of esterification (EDtitr), the degree of esterification calculated from the analysis of 1H NMR spectra (EDNMR), and the degree of itaconic anhydride conversion—calculation based on 13C NMR spectra (%X13CNMR). In each of statistical models, the significance of the changed synthesis parameters was determined. Optimal conditions are when OH/COOH ratio is equal to 1.5, temperature is 140 °C and time of reaction is 5 h. The higher OH/COOH ratio, temperature and longer the experiment time, the higher the value of the degree of esterification and the degree of anhydride conversion

Optimizing the conditions of PGSu synthesiswith simplex method

Poly(glycerol succinate) – PGSu – is one of glycerol polyesters which has focused nowadays the interestof scientists developing new biomaterials. Probably the polyester could be used as a drug carrier or asa cell scaffold in tissue engineering. Due to its potential use in medicine, it is extremely important todevelop a synthesis and then optimize it to obtain a material with desired properties. In this work oneflask two-step polycondensation of glycerol and succinic anhydride to PGSu is presented. Synthesiswas optimized with the simplex method and also described using a second-degree equation with twovariables (temperature and time) to better find the optimum conditions. PGSu was characterized byFTIR spectroscopy, NMR spectroscopy, degree of esterification was determined, and also molecularweight was calculated for each experiment using Carothers equation. A new synthesis route wasdeveloped and optimized. Temperature and time influence on molecular weight and esterificationdegree of obtained polyester are presented. Based on experiments conducted in this work, it waspossible to obtain poly(glycerol succinate) with molecular weight of 6.7 kDa

The catalyst-free polytransesterification for obtaining linear PGS optimized with use of 22 factorial design

Poly(glycerol sebacate) (PGS) is a polyester that is particularly useful for tissue engineering appli- cations. Many researchers have focused on the application and characterization of materials made from PGS. Synthesis is often superficially described, and the prepolymer is not characterized before crosslinking. Considering the different functionality of each monomer (glycerine – 3, sebacic acid – 2), materials with a branched structure can be obtained before the crosslinking process. Branched struc- tures are not desirable for elastomers. In this work, method to obtain linear PGS resins is presented. Moreover, synthesis was optimized with the use of the Design of Experiments method for minimizing the degree of branching and maximizing the molecular weight. The process was described via mathe- matical models, which allows to the association of process parameters with product properties. In this work ca. 1kDa and less than 10% branched PGS resin was produced. This resin could be used to make very flexible elastomers because branching is minimized

Ocena właściwości antymikrobiologicznych proleków chlorofenezyny

Spheres of prodrug of polylactide (PLA) or polycaprolactone (PCL) or a copolymer thereof with chlorphenesin (CF) were obtained. Furthermore spheres with an active substance additionally dispersed in the prodrug matrix – hybrid spheres – were prepared. The antimicrobial properties of the prodrug forms obtained were investigated towards bacteria, yeast, and filamentous fungi to verify whether the CF activity of the new formulations maintains. This research shows a wide spectrum of antimicrobiological application, especially when using CF as a preservative.Otrzymano sfery z proleku chlorofenezyny (CF) i polilaktydu (PLA), polikaprolaktonu (PCL) lub ich kopolimeru, a także sfery hybrydowe z substancją aktywną dodatkowo rozproszoną w matrycy proleku. W celu sprawdzenia, czy aktywność CF została zachowana, zbadano właściwości antymikrobiologiczne wszystkich otrzymanych form proleku wobec bakterii, drożdży i grzybów strzępkowych. Uzyskane wyniki wskazują na możliwe szerokie spektrum aplikacji tych form leku, szczególnie w charakterze konserwantu

Poly(glycerol itaconate) Crosslinking via the aza-Michael Reaction—A Preliminary Research

In unsaturated glycerol polyesters, the C=C bond is present. It makes it possible to carry out post-polymerisation modification (PPM) reactions, such as aza-Michael addition. This reaction can conduct crosslinking under in-situ conditions for tissue engineering regeneration. Until now, no description of such use of aza-Michael addition has been described. This work aims to crosslink the synthesised poly(glycerol itaconate) (PGItc; P3), polyester from itaconic acid (AcItc), and glycerol (G). The PGItc syntheses were performed in three ways: without a catalyst, in the presence of p-toluenesulfonic acid (PTSA), and in the presence of zinc acetate (Zn(OAc)2). PGItc obtained with Zn(OAc)2 (150 °C, 4 h, G:AcItc = 2:1) was used to carry out the aza-Michael additions. Crosslinking reactions were conducted with each of the five aliphatic diamines: 1,2-ethylenediamine (1,2-EDA; A1), 1,4-butanediamine (1,4-BDA; A2), 1,6-hexanediamine (1,6-HDA; A3), 1,8-octanediamine (1,8-ODA; A4), and 1,10-decanediamine (1,10-DDA; A5). Four ratios of the proton amine group: C=C bond were investigated. The maximum temperature and crosslinking time were measured to select the best amine for the addition product’s application. FTIR, 1H NMR, DSC, and TG analysis of the crosslinked products were also investigated