scholarly journals Hydroxypropylmethylcellulose as a film and hydrogel carrier for ACP nanoprecursors to deliver biomimetic mineralization

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhe Wang ◽  
Zihuai Zhou ◽  
Jiayan Fan ◽  
Leiqing Zhang ◽  
Zhixin Zhang ◽  
...  

AbstractDemineralization of hard tooth tissues leads to dental caries, which cause health problems and economic burdens throughout the world. A biomimetic mineralization strategy is expected to reverse early dental caries. Commercially available anti-carious mineralizing products lead to inconclusive clinical results because they cannot continuously replenish the required calcium and phosphate resources. Herein, we prepared a mineralizing film consisting of hydroxypropylmethylcellulose (HPMC) and polyaspartic acid-stabilized amorphous calcium phosphate (PAsp-ACP) nanoparticles. HPMC which contains multiple hydroxyl groups is a film-forming material that can be desiccated to form a dry film. In a moist environment, this film gradually changes into a gel. HPMC was used as the carrier of PAsp-ACP nanoparticles to deliver biomimetic mineralization. Our results indicated that the hydroxyl and methoxyl groups of HPMC could assist the stability of PAsp-ACP nanoparticles and maintain their biomimetic mineralization activity. The results further demonstrated that the bioinspired mineralizing film induced the early mineralization of demineralized dentin after 24 h with increasing mineralization of the whole demineralized dentin (3–4 µm) after 72–96 h. Furthermore, these results were achieved without any cytotoxicity or mucosa irritation. Therefore, this mineralizing film shows promise for use in preventive dentistry due to its efficient mineralization capability. Graphical Abstract

2021 ◽  
Author(s):  
Zhe Wang ◽  
Zihuai Zhou ◽  
Jiayan Fan ◽  
Leiqing Zhang ◽  
Zhixin Zhang ◽  
...  

Abstract Demineralization of tooth hard tissues leads to dental caries, which causes health problem and economic burden throughout the world. Biomimetic mineralization strategy is expected to reverse initial dental caries. Commercially available mineralizing anti-carious products lead to indefinite clinical results because they could not continuously replenish calcium and phosphate resources. Herein, we prepared a novel mineralizing film (NMF) consisting of hydroxypropylmethylcellulose (HPMC) and polyaspartic acid-stabilized amorphous calcium phosphate (PAsp-ACP) nanoparticles. HPMC containing multiple hydroxyls is a gel-forming material that could be either desiccated to be a dry film or gradually changed into gel in moist milieu. The HPMC was, for the first time, used as a carrier of PAsp-ACP nanoparticles for delivering biomimetic mineralization in moist milieu. Our results indicated the hydroxyls and methoxyls of HPMC could assist the stability of PAsp-ACP nanoparticles and maintain their bioactivity of mineralization. The results further demonstrated that the NMF bioinspired the early mineralization of demineralized dentin at 24 hrs and the heavy mineralization of the whole demineralized dentin (3-4 µm) at 72-96 hrs without any cytotoxicity and mucosa irritation. Therefore, the NMF might be promising mineralizing strategy for preventive dentistry with efficient mineralization capability.


Author(s):  
Ю.И. Цой

Задача получения однородного состава ЛКМ сводится к правильному выбору пленкообразователей и соответствующих растворителей и, в случае необходимости, разбавителей и добавок. На основе положений теории растворимости была проведена оценка совместимости компонентов и стабильности таких систем. Критериями оценки были приняты параметры растворимости и термодинамического взаимодействия. Исследовали совместимость алкидных лаков с аминоформальдегидными смолами в бутаноле, и результаты этих исследований представлены в треугольной фазовой диаграмме. Для оценки совместимости смол по результатам расчета параметров термодинамического взаимодействия были построены спинодали для тройных систем. Как показывает анализ результатов проведенных исследований, даже при большой разности ?? = |?12 – ?13| = 0,2 наблюдается небольшая область несовместимости. С уменьшением разности ?? область несовместимости сужается. При ?23 > ?с область несовместимости расширяется как для ? = 0,2, так и для ?? = 0,1 и ?? = 0. Таким образом, для таких систем на совместимость компонентов, в первую очередь, влияет их взаимодействие между собой – чем оно больше, тем лучше они совместимы. Проведенные исследования показали, что парциальные параметры растворимости, учитывающие природу когезионных сил, более объективно характеризуют растворимость пленкообразующих смол в органических растворителях, чем их общий параметр растворимости. Растворимость пленкообразующих алкидных и этерифицированных аминоформальдегидных смол в органических растворителях обусловлена термодинамическим взаимодействием молекулярных сил различной природы. Стабильность смеси алкидной и этерифицированной аминоформальдегидной смолы в бутаноле обусловлена в большей степени термодинамическим взаимодействием молекулярных сил; при этом степень бутанолизации меламиноформальдегидной смолы оказывает наибольшее влияние на стабильность cистемы. Проведенные исследования по стабильности лакокрасочных смесей из различных пленкообразующих смол на основе рассмотренных критериев оценки могут быть использованы для совершенствования технологии защитно-декоративной отделки древесины. The problem of obtaining a homogeneous composition of the coatings is reduced to the proper selection of film-forming agents, and diluent and, if appropriate, diluents and additives. On the basis of the theory of solubility, we have carried out the assessment of the compatibility of the components and stability of such systems. The evaluation criteria were adopted the parameters of the solubility and thermodynamic interaction. Researched the compatibility with alkyd varnishes aminoformaldehyde resin in butanol, and the results of these studies are presented in the triangular phase diagram. To evaluate the compatibility of the resins according to the results of calculation of thermodynamic parameters of interaction were built spinodal for ternary systems. As the analysis of the results of the studies, even when the difference ??|?12 – ?13| = 0,2 there is a small area of incompatibility. With the decrease of the difference ? ? region incompatibility narrows. When ?23> ?с region incompatibility extends to ?? = 0,2, and for ?? = 0.1 and ?? = 0. Thus, for such systems, compatibility of components, primarily, affects their interaction with each other – the further away it is, the better they are compatible. Studies have shown that the partial solubility parameters, which take into account the nature of cohesive forces, more objectively characterize the solubility of film-forming resins in organic solvents than their total solubility parameter. The solubility and film-forming aminoformaldehyde esterified alkyd resins in organic solvents due to thermodynamic interaction of molecular forces of different nature. Тhe stability of the mixture and aminoformaldehyde esterified alkyd resin in butanol is generated largely by thermodynamic forces of molecular interaction; the degree of butanolate melamine-formaldehyde resin has the greatest effect on the stability of the system. Conducted research on the stability of the paint mixtures of various film-forming resins on the basis of the evaluation criteria can be used to improve the technology of protective and decorative wood finish.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Veniamin Zheleznov ◽  
Aleksey Golikov ◽  
Tatiana Sokolnitskaya ◽  
Sergey Ivannikov

Abstract The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.


1979 ◽  
Vol 57 (18) ◽  
pp. 2464-2469 ◽  
Author(s):  
David Victor Fikis ◽  
William John Murphy ◽  
Robert Anderson Ross

Infrared spectra of the surfaces of vanadium pentoxide and vanadium pentoxide containing 9.09 mol% caesium and potassium, as sulphates, have been determined after exposure to 2-propanol for various times. Interpretation of the spectra leads to the proposal that the principal source of catalyst activity may be associated with surface hydrogen and hydroxyl groups on V5+ and V4+ sites. The "stability" of the catalysts towards reduction by the alcohol was consistent with the activity series derived from kinetic measurements: V2O5 (pure) < V2O5 (Cs) < V2O5 (K). The degree of sample reduction has also been assessed qualitatively by measurements of the ratio of surface area before to that after reaction and the same catalyst sequence was established. The trend in surface area ratios was similar to that shown by the surface "Tammann" temperatures of vanadium pentoxide and alkali metal sulphates which has been taken to imply that the ease and (or) extent with which the sulphates enter into inter-solid reactions with the oxide in the preparation stage may exert influence on the subsequent reducibility of the individual members of the catalyst series.


Author(s):  
RIVANTI IRMADELA DEVINA ◽  
ADELINE CLARISSA ◽  
NILAKESUMA DJAUHARIE ◽  
KAMIZAR NAZAR ◽  
RATNA MEIDYAWATI

Objective: This study aims to analyze remineralization that occurred in demineralized dentin following polyaspartic acid (pAsp) in PILP immersion.Methods: Sixteen dentin block samples were immersed in demineralized solution. The samples were divided into controls (no pAsp immersion) orpAsp immersion for 3, 7, or 14 days (n’s=4). The samples were evaluated using a scanning electron microscope (SEM) to observe morphology andenergy-dispersive X-ray (EDX) to observe calcium and phosphate levels.Results: SEM revealed that pAsp immersion resulted in significantly higher dentin remineralization compared to the control group. However, therewere no significant differences among 3, 7, and 14 days of immersion. EDX revealed that remineralization occurred by the deposition of calcium andphosphate ions.Conclusion: Including pAsp in the PILP process produced rapid remineralization of demineralized dentin.


2017 ◽  
Vol 24 (34) ◽  
pp. 26534-26544 ◽  
Author(s):  
Zidan Yuan ◽  
Shaofeng Wang ◽  
Xu Ma ◽  
Xin Wang ◽  
Guoqing Zhang ◽  
...  

2014 ◽  
Vol 70 (a1) ◽  
pp. C655-C655
Author(s):  
James Kaduk ◽  
Alagappa Rammohan

Computational studies of > 15 new crystal structures and the 10 previously-reported structures of alkali metal citrates provide insight into why the atoms are where they are. The metal-citrate bonding is predominantly ionic, with very little covalent character, which decreases as the cation size increases. Bond valence calculations indicate that most cations are crowded, and that the crowding decreases as the cation size increases. Although most oxygen atoms coordinate to the metals, a few do not, and they tend to be the least-negative oxygens. Both the citrate hydroxyl groups and water molecules tend to bridge two cations, and the carboxylate coordination is more varied. The solid state energy differences are dominated by differences in van der Waals and electrostatic energy contributions. In the Li and Na salts, the citrate anion occurs predominantly in a higher-energy "kinked" conformation, rather than the extended lowest-energy conformation observed in salts of the larger cations. Detailed conformational analysis of the citrate anions enables quantification of the conformational energy costs in these solids. Hydrogen bonding is important to the stability of these salts. The Mulliken overlap population in the hydrogen bonds provides a quantitative measure of their strength, and permits identification of long (weak) interactions which are significant in some of these compounds. Patterns in both the local environments of the hydrogen bonds and the more-extended features (graph sets) are noted. Polymorphs and sets of isostructural compounds permit more-detailed analysis of the structures and energetics in these compounds. The order of ionization of the three carboxylic acid groups is in general central/terminal/terminal, but there are two exceptions. While we have concentrated on salts containing a single alkali metal cation (and hydrogen), the structures of NaK2C6H5O7 and NaKHC6H5O7 provide an exciting window on a larger universe of mixed salts.


2021 ◽  
Vol 11 (3-S) ◽  
pp. 15-18
Author(s):  
Vipul Wayal ◽  
K. Nagasree ◽  
B. A. Vishwanath

The objective of the present study is to formulate and evaluate Silk based film forming spray for wound healing. On the wound surface the solution solidifies into a film which can deliver the active moiety on site of action. The spray solution was prepared by simple mixing of active extract of Centella Asiatica, Silk Protein and various film forming polymers. Silk protein form scaffold for active fibroblast movement and Asiaticosides from Centella Asiatica extract improve and fasten collagen synthesis. A clear yellowish solution was obtained. The formulations (F1-F8) had a pH range between 5.5–6.5, which was close to the pH of skin. The viscosity of formulation in range of 25–50 cps, completely dry film formed within 5 min in open environment. The Effects of polymers, plasticizers and solvents on spreadability. Surface tension and Spray angle were studied. The high content of ethanol in the formulation fastens the drying time. The results indicated that formulation (F8) showed good spreadability and less drying time. Keywords: Film forming spray, Wound healing, Silk protein, Asiaticoside, Scaffold


Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 787 ◽  
Author(s):  
Shiuh-Tsuen Huang ◽  
Yi-An Hung ◽  
Meei-Ju Yang ◽  
Iou-Zen Chen ◽  
Jeu-Ming Yuann ◽  
...  

Catechins belonging to polyhydroxylated polyphenols are the primary compounds found in green tea. They are associated with many physiological properties. Epicatechin (EC) is a non-gallate-type catechin with four phenolic hydroxyl groups attached. The changes in EC treated with color light illumination in an alkaline condition were investigated by chromatographic and mass analyses in this study. In particular, the superoxide anion radical (O2•−) was investigated during the EC photolytic process. EC is unstable under blue light illumination in an alkaline solution. When EC was treated with blue light illumination in an alkaline solution, O2•− was found to occur via a photosensitive redox reaction. In addition, the generation of monomeric, dimeric, and trimeric compounds is investigated. On the other hand, epigallocatechin gallate (EGCG), which is a gallate-type catechin, is stable under blue light illumination in an alkaline solution. Adding EGCG, during the blue light illumination treatment of EC decreased photolytic formation, suggesting that gallate-type catechins can suppress the photosensitive oxidation of EC. Gallate-type catechins are formed via the esterification of non-gallate-type catechins and gallic acid (GA). The carbonyl group on the gallate moiety of gallate-type catechins appears to exhibit its effect on the stability against the photosensitive oxidation caused by blue light illumination.


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