Abstract:Phenylboronic acids are a class of compounds that bind glucose and other sugars. When polymerized into hydrogels, they provide a convenient nonenzymatic means for sensing glucose concentration, provided competing sugars are present at negligible concentrations. In this paper we provide a comprehensive study of swelling of hydrogels containing methacrylamidophenylboronic acid (MPBA), as a function of pH and concentration of either glucose or fructose. In one set of hydrogels, MPBA is substituted at 20 mol· % in… Show more
“…Here, it can be revealed that the binding of glucose moieties with the mineralized hydrogels gradually increases the charge density within the hydrogels, hence enhances the hydrophilicity within the hydrogel which finally leads to the rise in the swelling capacity (Kim et al 2014). …”
Section: Resultsmentioning
confidence: 99%
“…As far as the swelling behavior is concerned, two main important phenomenons are focused: (1) Donnan osmotic pressure and (2) elastic property within the polymeric network structure. When these two phenomena become equal, no further uptake of the solution takes place by the material and hence super-saturation stage is attained (Kim et al 2014). Fig.…”
Biomaterials having stimuli response are interesting in the biomedical field. This paper reports about swelling response and internalstructural of biomineralized (CaCO3) polyvinylpyrrolidone (PVP) carboxymethylcellulose (CMC) hydrogel having various thicknesses (0.1–0.4 mm). Samples were tested in aqueous solution using temperature ranges from 10 to 40 °C; pH varies from 4 to 9, time 60 min. In addition, an experiment was conducted in the presence of simulated biological solutions (SBS): glucose (GS), physiological fluid (PS) and urea (US) at temperature 37 °C and pH 7.5 for 180 min. It is noticed that the maximum swelling ratio reached in 30–40 °C at pH 7 in aqueous solution. Among biological fluids, the swelling ratio shows: US > PS > GS at temperature 37 °C, pH 7.5, time 150 min. The equilibrium swelling ratio of the test sample in SBS and their non-reformative apparent structure confirm that biomineralized (CaCO3) PVP–CMC hydrogel can be acclaimed for medical application like bone tissue engineering.Graphical Abstract
“…Here, it can be revealed that the binding of glucose moieties with the mineralized hydrogels gradually increases the charge density within the hydrogels, hence enhances the hydrophilicity within the hydrogel which finally leads to the rise in the swelling capacity (Kim et al 2014). …”
Section: Resultsmentioning
confidence: 99%
“…As far as the swelling behavior is concerned, two main important phenomenons are focused: (1) Donnan osmotic pressure and (2) elastic property within the polymeric network structure. When these two phenomena become equal, no further uptake of the solution takes place by the material and hence super-saturation stage is attained (Kim et al 2014). Fig.…”
Biomaterials having stimuli response are interesting in the biomedical field. This paper reports about swelling response and internalstructural of biomineralized (CaCO3) polyvinylpyrrolidone (PVP) carboxymethylcellulose (CMC) hydrogel having various thicknesses (0.1–0.4 mm). Samples were tested in aqueous solution using temperature ranges from 10 to 40 °C; pH varies from 4 to 9, time 60 min. In addition, an experiment was conducted in the presence of simulated biological solutions (SBS): glucose (GS), physiological fluid (PS) and urea (US) at temperature 37 °C and pH 7.5 for 180 min. It is noticed that the maximum swelling ratio reached in 30–40 °C at pH 7 in aqueous solution. Among biological fluids, the swelling ratio shows: US > PS > GS at temperature 37 °C, pH 7.5, time 150 min. The equilibrium swelling ratio of the test sample in SBS and their non-reformative apparent structure confirm that biomineralized (CaCO3) PVP–CMC hydrogel can be acclaimed for medical application like bone tissue engineering.Graphical Abstract
“…Thus PBA is an excellent Lewis acid, which complexes with Lewis bases such as:OH − and –N: groups. The most commonly studied PBA, methacrylamidophenylboronic acid (MPBA) acts, when in a hydrogel, as an acid with pKa≈8.5 [150, 151]. At physiologic pH and in the absence of glucose, only a small fraction of the MPBA units are ionized.…”
Section: Stimuli Responsive Hydrogelsmentioning
confidence: 99%
“…Of more concern is the fact that pH in the blood can vary, especially during diabetes. Since the mechanism described above relies on an acid-base binding step, the degree of swelling depends jointly on pH and glucose concentration [151, 156]. The latter problem can be averted, in principle, either by lowering the pKa of PBA by increasing the electron withdrawing character of the groups attached to or neighboring the phenyl ring [157-159], or by incorporating Lewis base groups such as amines into the hydrogel, which can take over the role played by:OH − ions [148, 151, 160].…”
Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an “on-demand” basis. So called “stimuli-responsive” and “intelligent” systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two.
“…Polymeric materials with specific stimuli responsive behavior are widely used for medical and biotechnological applications [1][2][3][4]. In particular, polymeric hydrogel systems have attracted great interest due to their soft and flexible consistency and their ability to absorb large amounts of water, keeping at the same time their three-dimensional stability [5,6].…”
Abstract.1 This paper reports on a study of novel heterohydrogel materials with regular inclusions of the dispersed phase such as polystyrene latex nanoparticles. Synthesized 3D hydrogel matrices contain a balanced number of cross-links and a defined amount of polystyrene nanoparticles with 50 or 85 nm in radius. This study has shown that the obtained hydrogel matrices are capable of changing the swelling degree and their optical properties depending on the size and concentration of the dispersed nanoparticles. The results of the performed studies revealed that the synthesized 3D hydrogels are sensitive for even small changes of glucose concentration and therefore are very promising materials for biosensors.
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