Lin Shijun,Jiang Sirui,Zhang Yuchen,Dai Zhengwei,Dai Yu,Xia Fan,Zhang Xiaojin
Gold nanorod (AuNR) nanocomposite hydrogels have attracted increasing attention due to the photothermal effect of AuNRs. However, a facile strategy that avoids multi-step surface modification for synthesis of AuNR crosslinkers is still a critical challenge. Here, AuNRs crosslinking PNIPAM hydrogels were prepared by polymerization of NIPAM with N , N ′-bis(acryloyl)cystamine (BACA)-modified AuNRs as crosslinkers. BACA contains a disulfide bond in the structure. Dynamic and reversible Au-thiolate bonding was formed by directly mixing AuNRs and BACA to facilely prepare AuNR crosslinkers before hydrogel formation. The addition of AuNRs gives hydrogels their photothermal effect and remarkable mechanical behaviors. Hydrogels could repeatedly adhere to the surface of pigskin, metal, plastic, and glass with a relatively stable adhesion. The damaged hydrogels heal within 2 min with near-infrared (NIR) laser (808 nm, 300 mW∙cm −2 ) irradiation. This work provides a line of thinking for improvement of PNIPAM hydrogels, making them promising for further applications in biomedicine.
Weiling Chen,Xingtian Chen,Wenjing Liang,Huiqing Liao,Haisang Qin,Bangdong Chen,Minmin Ai
In this study, the moderation–excess interaction of epigallocatechin gallate (EGCG) and calcium ions (Ca 2+ ) to the gelation performance of transparent egg white protein (EWP) gel (EWG) was explored. The oxidation of EGCG introduced a yellowish-brown EWG, whereas the weakening of Ca 2+ ionic bonds caused a notable reduction in the hardness of EWG, from 120.67 g to 73.57 g. Achieving the optimal EGCG-to-Ca 2+ ratio in EWG conferred enhanced water-holding capacity to 86.98%, while an excess of EGCG attributed to the creation of a three-dimensional structure within the void “walls”. The elevated presence of EGCG influenced the ionic bonds and hydrophobic interactions, thereby presenting a moderate–excess relationship with sulfhydryl and disulfide bonds, β-sheet, and α-helical structures. Notably, EGCG reduced the digestibility of EWG to 50.06%, while concurrently fostering the creation of smaller particle sizes. This study provides a scientific basis for the controllable preparation and quality regulation of transparent EWG.
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