Polysaccharide matrices formed via thermoinduced sol–gel phase transition are promising systems u... more Polysaccharide matrices formed via thermoinduced sol–gel phase transition are promising systems used as drug carriers and minimally invasiveness scaffolds in tissue engineering. The strong shear field generated during injection may lead to changes in the conformation of polymer molecules and, consequently, affect the gelation conditions that have not been studied so far. Chitosan (CS) and hydroxypropyl cellulose (HPC) sols were injected through injection needles (14 G–25 G) or sheared directly in the rheometer measuring system. Then the sol–gel phase transition conditions were determined at 37 °C using rheometric, turbidimetric, and rheo-optical techniques. It was found that the use of low, respecting injection, shear rates accelerate the gelation, its increase extends the gelation time; applying the highest shear rates may significantly slow down (HPC) or accelerate gelation (CS) depending on thixotropic properties. From a practical point of view, the conducted research indicates t...
Low-concentrated colloidal chitosan systems undergoing a thermally induced sol–gel phase transiti... more Low-concentrated colloidal chitosan systems undergoing a thermally induced sol–gel phase transition are willingly studied due to their potential use as minimally invasive injectable scaffolds. Nevertheless, instrumental injectability tests to determine their clinical utility are rarely performed. The aim of this work was to analyze the flow phenomenon of thermosensitive chitosan systems with the addition of disodium β-glycerophosphate through hypodermic needles. Injectability tests were performed using a texture analyzer and hypodermic needles in the sizes 14G–25G. The rheological properties were determined by the flow curve, three-interval thixotropy test (3ITT), and Cox–Merz rule. It was found that reducing the needle diameter and increasing its length and the crosshead speed increased the injection forces. It was claimed that under the considered flow conditions, there was no need to take into account the viscoelastic properties of the medium, and the model used to predict the in...
Progress on Chemistry and Application of Chitin and its Derivatives, 2020
The aim of this paper was to conduct preliminary instrumental tests to determine the possibility ... more The aim of this paper was to conduct preliminary instrumental tests to determine the possibility of injection applications for thermosensitive chitosan systems, including injection needles and application conditions. Among the many biomedical and pharmaceutical applications of chitosan, the minimally invasive thermosensitive scaffolds that form in vivo are an interesting solution. Despite many studies on colloidal chitosan systems undergoing sol-gel phase transition, almost no studies have examined their injectability. It has been stated that the use of acetic acid as a solvent reduces the forces needed for injection. Moreover, the key impact of injection temperature was determined. Storing the medium at room temperature before the injectability test led to a decrease in the value of forces needed for injection. The obtained results are discussed based on the change of the rheological properties of the chitosan hydrogels.
The presented work describes the method of preparation of thermosensitive chitosan hydrogels usin... more The presented work describes the method of preparation of thermosensitive chitosan hydrogels using calcium β-glycerophosphate salt as the only pH neutralizing agent and supporting the crosslinking process. The presence of calcium ions instead of sodium ions is particularly important in the case of scaffolds in bone tissue engineering. Rheological and physicochemical properties of low concentrated chitosan solutions with the addition of calcium β-glycerophosphate were investigated using rotational rheometry techniques, Zeta potential (by electrophoresis), XPS, and SEM analysis together with an EDS detector. It was found to be possible to prepare colloidal solutions of chitosan containing only calcium β-glycerophosphate (without sodium ions) undergoing a sol-gel phase transition at the physiological temperature of the human body. It has also been shown that it is possible to further enrich the obtained cellular scaffolds with calcium ions. Using the addition of calcium carbonate, hydr...
In recent years, intensive research has been carried out on the use of hydrogels obtained from na... more In recent years, intensive research has been carried out on the use of hydrogels obtained from natural polymers, mainly chitosan. These products are increasingly replacing solutions based on synthetic materials in medicine. This publication presents the results of studies on the sol-gel transition of chitosan solutions as the base material for the preparation of thermosensitive hydrogels for potential applications in tissue engineering. The measurements were carried out for systems consisting of chitosan lactate and chitosan chloride solutions using β-glycerol phosphate disodium salt pentahydrate and uridine 5′-monophosphate disodium salt as the cross-linking agents. The sol-gel transition point of the solutions was determined based on the rheological measurements in the cone-plate configuration of the rotational rheometer and experiments performed using the method of nuclear magnetic resonance. The obtained results showed a significant influence of the cross-linking agent on the co...
Kontrolowane uwalnianie substancji czynnych jest jednym z głównych nurtów badań w przemyśle farma... more Kontrolowane uwalnianie substancji czynnych jest jednym z głównych nurtów badań w przemyśle farmaceutycznym. Sprzyja to tworzeniu nowych leków, wykazujących wyższą skuteczność oraz ograniczone działania niepożądane. Podstawową formę leków w kontrolowanych systemach uwalniania stanowi połączenie substancji czynnej z polimerową matrycą o specjalnie dobranej przepuszczalności. Jednym z rozwiązań stosowanych obecnie w farmakologii jest użycie matryc polimerowych tworzących układy koloidalne. Przemiany fazowe zol-żel takich układów wywołane są zmianami pH lub temperatury. Układy te można zaliczyć do tzw. inteligentnych systemów dystrybucji leków. Wzbudzają one szczególne zainteresowanie zwłaszcza w aspekcie stosowania ich jako nośników leków oraz jako materiałów do hodowli komórkowej. Układy polimerowe inteligentnych systemów dostarczania leków oparte są głownie na związkach zwanych hydrożelami. Są to trójwymiarowe sieci, cechujące się dużą absorpcją i zdolnością utrzymania wody w swojej...
ABSTRACT The combination of medicinal substance and an appropriate polymer matrix with specially ... more ABSTRACT The combination of medicinal substance and an appropriate polymer matrix with specially adjusted permeability has became a basic form of medicine in the controlled drag delivery. One of main solutions used recently in pharmacology is the application of polymer matrices which form colloidal systems. The sol-gel phase transition is inhibited by a change of pH or temperature. Thermosensitive systems are produced from polymers whose sol-gel transition in water solutions depends on temperature. Thermosensitive hydrogel systems are currently obtained mainly from poly(N-isopropylacrylamide) (PNIPA), copolymer (polyethylene oxide - polypropylene oxide - polyethylene oxide), polyethylene glycol, lactic acid copolymer with glycolic acid and polyethylene glycol, and polysaccharides (xyloglucane, ethylcellulose, hydroxyethylcellulose and chitosan). At the temperature below 25°C these systems occur in the form of sols which at human body temperature are transformed into gels. Such systems belong to the so called intelligent ones and are a subject of special interest, particularly in view of their possible use as drug carriers and also as material for cell culture in the past.
Introduction Chitosan is a semi-crystalline amino-polysaccharide obtained through deacetylation o... more Introduction Chitosan is a semi-crystalline amino-polysaccharide obtained through deacetylation of chitin. Due to its physicochemical properties, chitosan has a variety of applications in sewage treatment processes (chelating properties), food industry and biomedicine – in processes of creating smart drug carriers [1]. Chitosan is dissolved in low concentrated solutions of organic and non-organic acids in which it forms salts with dissolvent ions. Chitosan properties change from hydrophobic to hydrophilic and a colloidal system is created in which the polymer chains remain dispersed in a continuous medium – acid solution. Such a system shows a possibility for a sol-gel phase transition. Chitosan hydrogels may form as a result of increasing the concentration of the polymer [2], through the change of pH of the solution or through heating it [1,3,4]. The aim of this work was to create hydrogels sensitive to temperature changes from low-concentration solutions of chitosan and to describ...
The thermosensitive hydrogels are widely used in tissue engineering due to their non-invasive app... more The thermosensitive hydrogels are widely used in tissue engineering due to their non-invasive application. Special interest of researchers, due to the specific characteristics of both materials, is aimed at composites of natural origin obtained from chitosan hydrogels combined with collagen. The mechanical properties of the thermosensitive chitosan-fish collagen hydrogels and the sol-gel phase transition parameters were determined by the rotational rheometry measurement techniques. Based on comparison of the obtained storage modulus G' curves, it was found that the addition of collagen negatively affects the mechanical properties of composite scaffolds. The addition of this protein substance decreases their elasticity. Only the smallest concentration (0.25g collagen/1 g chitosan) of collagen improves the mechanical properties of composite hydrogels, from 56 kPa to 61 kPa. Conducted non-isothermal studies allowed to conclude that the addition of collagen causes an increasing temp...
Polysaccharide matrices formed via thermoinduced sol–gel phase transition are promising systems u... more Polysaccharide matrices formed via thermoinduced sol–gel phase transition are promising systems used as drug carriers and minimally invasiveness scaffolds in tissue engineering. The strong shear field generated during injection may lead to changes in the conformation of polymer molecules and, consequently, affect the gelation conditions that have not been studied so far. Chitosan (CS) and hydroxypropyl cellulose (HPC) sols were injected through injection needles (14 G–25 G) or sheared directly in the rheometer measuring system. Then the sol–gel phase transition conditions were determined at 37 °C using rheometric, turbidimetric, and rheo-optical techniques. It was found that the use of low, respecting injection, shear rates accelerate the gelation, its increase extends the gelation time; applying the highest shear rates may significantly slow down (HPC) or accelerate gelation (CS) depending on thixotropic properties. From a practical point of view, the conducted research indicates t...
Low-concentrated colloidal chitosan systems undergoing a thermally induced sol–gel phase transiti... more Low-concentrated colloidal chitosan systems undergoing a thermally induced sol–gel phase transition are willingly studied due to their potential use as minimally invasive injectable scaffolds. Nevertheless, instrumental injectability tests to determine their clinical utility are rarely performed. The aim of this work was to analyze the flow phenomenon of thermosensitive chitosan systems with the addition of disodium β-glycerophosphate through hypodermic needles. Injectability tests were performed using a texture analyzer and hypodermic needles in the sizes 14G–25G. The rheological properties were determined by the flow curve, three-interval thixotropy test (3ITT), and Cox–Merz rule. It was found that reducing the needle diameter and increasing its length and the crosshead speed increased the injection forces. It was claimed that under the considered flow conditions, there was no need to take into account the viscoelastic properties of the medium, and the model used to predict the in...
Progress on Chemistry and Application of Chitin and its Derivatives, 2020
The aim of this paper was to conduct preliminary instrumental tests to determine the possibility ... more The aim of this paper was to conduct preliminary instrumental tests to determine the possibility of injection applications for thermosensitive chitosan systems, including injection needles and application conditions. Among the many biomedical and pharmaceutical applications of chitosan, the minimally invasive thermosensitive scaffolds that form in vivo are an interesting solution. Despite many studies on colloidal chitosan systems undergoing sol-gel phase transition, almost no studies have examined their injectability. It has been stated that the use of acetic acid as a solvent reduces the forces needed for injection. Moreover, the key impact of injection temperature was determined. Storing the medium at room temperature before the injectability test led to a decrease in the value of forces needed for injection. The obtained results are discussed based on the change of the rheological properties of the chitosan hydrogels.
The presented work describes the method of preparation of thermosensitive chitosan hydrogels usin... more The presented work describes the method of preparation of thermosensitive chitosan hydrogels using calcium β-glycerophosphate salt as the only pH neutralizing agent and supporting the crosslinking process. The presence of calcium ions instead of sodium ions is particularly important in the case of scaffolds in bone tissue engineering. Rheological and physicochemical properties of low concentrated chitosan solutions with the addition of calcium β-glycerophosphate were investigated using rotational rheometry techniques, Zeta potential (by electrophoresis), XPS, and SEM analysis together with an EDS detector. It was found to be possible to prepare colloidal solutions of chitosan containing only calcium β-glycerophosphate (without sodium ions) undergoing a sol-gel phase transition at the physiological temperature of the human body. It has also been shown that it is possible to further enrich the obtained cellular scaffolds with calcium ions. Using the addition of calcium carbonate, hydr...
In recent years, intensive research has been carried out on the use of hydrogels obtained from na... more In recent years, intensive research has been carried out on the use of hydrogels obtained from natural polymers, mainly chitosan. These products are increasingly replacing solutions based on synthetic materials in medicine. This publication presents the results of studies on the sol-gel transition of chitosan solutions as the base material for the preparation of thermosensitive hydrogels for potential applications in tissue engineering. The measurements were carried out for systems consisting of chitosan lactate and chitosan chloride solutions using β-glycerol phosphate disodium salt pentahydrate and uridine 5′-monophosphate disodium salt as the cross-linking agents. The sol-gel transition point of the solutions was determined based on the rheological measurements in the cone-plate configuration of the rotational rheometer and experiments performed using the method of nuclear magnetic resonance. The obtained results showed a significant influence of the cross-linking agent on the co...
Kontrolowane uwalnianie substancji czynnych jest jednym z głównych nurtów badań w przemyśle farma... more Kontrolowane uwalnianie substancji czynnych jest jednym z głównych nurtów badań w przemyśle farmaceutycznym. Sprzyja to tworzeniu nowych leków, wykazujących wyższą skuteczność oraz ograniczone działania niepożądane. Podstawową formę leków w kontrolowanych systemach uwalniania stanowi połączenie substancji czynnej z polimerową matrycą o specjalnie dobranej przepuszczalności. Jednym z rozwiązań stosowanych obecnie w farmakologii jest użycie matryc polimerowych tworzących układy koloidalne. Przemiany fazowe zol-żel takich układów wywołane są zmianami pH lub temperatury. Układy te można zaliczyć do tzw. inteligentnych systemów dystrybucji leków. Wzbudzają one szczególne zainteresowanie zwłaszcza w aspekcie stosowania ich jako nośników leków oraz jako materiałów do hodowli komórkowej. Układy polimerowe inteligentnych systemów dostarczania leków oparte są głownie na związkach zwanych hydrożelami. Są to trójwymiarowe sieci, cechujące się dużą absorpcją i zdolnością utrzymania wody w swojej...
ABSTRACT The combination of medicinal substance and an appropriate polymer matrix with specially ... more ABSTRACT The combination of medicinal substance and an appropriate polymer matrix with specially adjusted permeability has became a basic form of medicine in the controlled drag delivery. One of main solutions used recently in pharmacology is the application of polymer matrices which form colloidal systems. The sol-gel phase transition is inhibited by a change of pH or temperature. Thermosensitive systems are produced from polymers whose sol-gel transition in water solutions depends on temperature. Thermosensitive hydrogel systems are currently obtained mainly from poly(N-isopropylacrylamide) (PNIPA), copolymer (polyethylene oxide - polypropylene oxide - polyethylene oxide), polyethylene glycol, lactic acid copolymer with glycolic acid and polyethylene glycol, and polysaccharides (xyloglucane, ethylcellulose, hydroxyethylcellulose and chitosan). At the temperature below 25°C these systems occur in the form of sols which at human body temperature are transformed into gels. Such systems belong to the so called intelligent ones and are a subject of special interest, particularly in view of their possible use as drug carriers and also as material for cell culture in the past.
Introduction Chitosan is a semi-crystalline amino-polysaccharide obtained through deacetylation o... more Introduction Chitosan is a semi-crystalline amino-polysaccharide obtained through deacetylation of chitin. Due to its physicochemical properties, chitosan has a variety of applications in sewage treatment processes (chelating properties), food industry and biomedicine – in processes of creating smart drug carriers [1]. Chitosan is dissolved in low concentrated solutions of organic and non-organic acids in which it forms salts with dissolvent ions. Chitosan properties change from hydrophobic to hydrophilic and a colloidal system is created in which the polymer chains remain dispersed in a continuous medium – acid solution. Such a system shows a possibility for a sol-gel phase transition. Chitosan hydrogels may form as a result of increasing the concentration of the polymer [2], through the change of pH of the solution or through heating it [1,3,4]. The aim of this work was to create hydrogels sensitive to temperature changes from low-concentration solutions of chitosan and to describ...
The thermosensitive hydrogels are widely used in tissue engineering due to their non-invasive app... more The thermosensitive hydrogels are widely used in tissue engineering due to their non-invasive application. Special interest of researchers, due to the specific characteristics of both materials, is aimed at composites of natural origin obtained from chitosan hydrogels combined with collagen. The mechanical properties of the thermosensitive chitosan-fish collagen hydrogels and the sol-gel phase transition parameters were determined by the rotational rheometry measurement techniques. Based on comparison of the obtained storage modulus G' curves, it was found that the addition of collagen negatively affects the mechanical properties of composite scaffolds. The addition of this protein substance decreases their elasticity. Only the smallest concentration (0.25g collagen/1 g chitosan) of collagen improves the mechanical properties of composite hydrogels, from 56 kPa to 61 kPa. Conducted non-isothermal studies allowed to conclude that the addition of collagen causes an increasing temp...
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