In Situ Cross-linking Polymerization-Induced Self-Assembly: Not Only Generates Cross-linked Structures But Also Promotes Morphology Transition by the Cross-linker

2021 ◽  
Author(s):  
Jamshid Kadirkhanov ◽  
Cheng-Lin Yang ◽  
Zi-Xuan Chang ◽  
Ren-Man Zhu ◽  
Cai-Yuan Pan ◽  
...  

Compared with the post-polymerization cross-linking strategy, in situ cross-linking by divinyl comonomers in polymerization-induced self-assembly (PISA) is a more straightforward and convenient approach to produce structurally stabilized nano-objects. However, cross-linking...

2020 ◽  
Vol 11 (22) ◽  
pp. 3654-3672 ◽  
Author(s):  
Wen-Jian Zhang ◽  
Jamshid Kadirkhanov ◽  
Chang-Hui Wang ◽  
Sheng-Gang Ding ◽  
Chun-Yan Hong ◽  
...  

This review discusses the strategies of core-cross-linking in most of the PISA literatures (including post-polymerization cross-linking, photo-cross-linking and in situ cross-linking) and the applications of the cross-linked nano-objects.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3637
Author(s):  
Yong Wang ◽  
Austin Green ◽  
Xiaomei Yao ◽  
Hang Liu ◽  
Saleha Nisar ◽  
...  

Improving the longevity of composite restorations has proven to be difficult when they are bonded to dentin. Dentin demineralization leaves collagen fibrils susceptible to enzymatic digestion, which causes breakdown of the resin–dentin interface. Therefore, measures for counteracting the enzymatic environment by enhancing dentin collagen’s resistance to degradation have the potential to improve the durability of dental composite restorations. This study aimed to evaluate the effects of polyphenol-rich extracts and a chemical cross-linker on the cross-linking interaction, resistance to digestion, and endogenous matrix metalloproteinase (MMP) activities of dentin collagen under clinically relevant conditions. Ten-µm-thick films were cut from dentin slabs of non-carious extracted human third molars. Following demineralization, polyphenol-rich extracts—including grape seed (GSE), green tea (GTE), and cranberry juice (CJE)—or chemical cross-linker carbodiimide with n-hydroxysuccinimide (EDC/NHS) were applied to the demineralized dentin surfaces for 30 s. The collagen cross-linking, bio-stabilization, and gelatinolytic activities of MMPs 2 and 9 were studied by using Fourier-transform infrared spectroscopy, weight loss, hydroxyproline release, scanning/transmission electron microscopy, and in situ zymography. All treatments significantly increased resistance to collagenase degradation and reduced the gelatinolytic MMP activity of dentin collagen compared to the untreated control. The CJE- and GSE-treated groups were more resistant to digestion than the GTE- or EDC/NHS-treated ones (p < 0.05), which was consistent with the cross-linking interaction found with FTIR and the in situ performance on the acid-etched dentin surface found with SEM/TEM. The collagen films treated with CJE showed the lowest MMP activity, followed by GSE, GTE, and, finally, EDC/NHS. The CJE-treated dentin collagen rapidly increased its resistance to digestion and MMP inhibition. An application of CJE as short as 30 s may be a clinically feasible approach to improving the longevity of dentin bonding in composite restorations.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 478
Author(s):  
Gjylije Hoti ◽  
Fabrizio Caldera ◽  
Claudio Cecone ◽  
Alberto Rubin Pedrazzo ◽  
Anastasia Anceschi ◽  
...  

The cross-linking density influences the physicochemical properties of cyclodextrin-based nanosponges (CD-NSs). Although the effect of the cross-linker type and content on the NSs performance has been investigated, a detailed study of the cross-linking density has never been performed. In this contribution, nine ester-bridged NSs based on β-cyclodextrin (β-CD) and different quantities of pyromellitic dianhydride (PMDA), used as a cross-linking agent in stoichiometric proportions of 2, 3, 4, 5, 6, 7, 8, 9, and 10 moles of PMDA for each mole of CD, were synthesized and characterized in terms of swelling and rheological properties. The results, from the swelling experiments, exploiting Flory–Rehner theory, and rheology, strongly showed a cross-linker content-dependent behavior. The study of cross-linking density allowed to shed light on the efficiency of the synthesis reaction methods. Overall, our study demonstrates that by varying the amount of cross-linking agent, the cross-linked structure of the NSs matrix can be controlled effectively. As PMDA βCD-NSs have emerged over the years as a highly versatile class of materials with potential applications in various fields, this study represents the first step towards a full understanding of the correlation between their structure and properties, which is a key requirement to effectively tune their synthesis reaction in view of any specific future application or industrial scale-up.


1984 ◽  
Vol 224 (3) ◽  
pp. 1019-1022
Author(s):  
E Kotthaus ◽  
W H Strätling

We have studied the HClO4-solubility of histones H1 and H5 in hen erythrocyte nuclei after treatment with the cross-linker dimethyl 3,3′-dithiobispropionimidate (DTPI). The amount of acid-soluble, non-cross-linked, H1 and H5 histones was drastically decreased, and that of acid-soluble H1/H5 histone dimers went through an optimum as the DTPI concentration was raised. Incubation of the HClO4-insoluble fraction with 2-mercaptoethanol regenerated the acid-solubility of H1/H5 histones in this fraction. When purified H1/H5 histones were treated with increasing concentrations of DTPI under non-cross-linking conditions, the amount of HClO4-soluble histones also greatly decreased, but to a much lesser extent if the DTPI treatment was followed by reduction with 2-mercaptoethanol. This decrease was inversely correlated to the proportion of amino groups modified. It is concluded that, when the cross-linker was used in large excess, the cross-linking reaction competed with a one-end reaction modifying the histones at lysine amino groups by cross-linker molecules, of which the imidoester groups that had not reacted were hydrolysed. It is suggested that this modification produced the changes in acid-solubility.


2020 ◽  
Vol 11 (26) ◽  
pp. 4335-4343 ◽  
Author(s):  
Jongmin Park ◽  
Nam Young Ahn ◽  
Myungeun Seo

Copolymerizing a cross-linker in the PISA process spontaneously produces branched core cross-linked block polymer micelles.


2014 ◽  
Vol 289 (14) ◽  
pp. 10057-10068 ◽  
Author(s):  
Sean E. Reichheld ◽  
Lisa D. Muiznieks ◽  
Richard Stahl ◽  
Karen Simonetti ◽  
Simon Sharpe ◽  
...  

2019 ◽  
Vol 52 (3) ◽  
pp. 1140-1149 ◽  
Author(s):  
Miao Chen ◽  
Jia-Wei Li ◽  
Wen-Jian Zhang ◽  
Chun-Yan Hong ◽  
Cai-Yuan Pan

RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 10710-10726
Author(s):  
Akanksha Pragya ◽  
Suhas Mutalik ◽  
Muhammad Waseem Younas ◽  
Siu-Kwong Pang ◽  
Pui-Kin So ◽  
...  

In situ, time-resolved characterisation of an alginate–acrylamide tough hydrogel dynamic formation process indicate routes to intervention and modification of chemo-physico-mechanical properties.


2013 ◽  
Vol 658 ◽  
pp. 56-60
Author(s):  
Li Qiu Zou ◽  
Guang Feng Wu

In this paper, the linear low density polyethylene (LLDPE) was melted and cross-linked by dicumyl peroxide (DCP) used to prepare cross-linked polyethylene (XPE). The gel content was determined by extraction method. The effect of content of cross-linker, cross- linked time, cross-linked temperature and other factors on the gel content were studied. It was found that the extraction time should be 18h for XPE. The gel content increased with the increasing of cross-linked time. When the cross-linked time was 10-15min, DCP was almost complete decomposition. The gel content was basically stable when the cross-linked temperature was 170-175 oC. The maximum of gel fraction was about 90%.


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