A one-step in-situ assembly strategy to construct PEG@MOG-100-Fe shape-stabilized composite phase change material with enhanced storage capacity for thermal energy storage

γ-aminobutyric acid (GABA) alleviated oxidative damage and programmed cell death in fresh-cut pumpkins

The regulation of γ-aminobutyric acid (GABA) on plant anti-oxygenation and programmed cell death (PCD) in fresh-cut pumpkins was investigated. Exogenous GABA positively promoted GABA accumulation and alleviated oxidant damage in pumpkins tissue. Pumpkins treated with GABA showed lower electrolyte leakage, reactive oxygen species (ROS) and MDA content, while higher activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) as compared to the non-treated tissues. Our results also found that GABA treatment retarded DNA degradation and cytochrome c release and delayed the apoptosis of pumpkin cells. On the other hand, the inhibitor of GABA generation, 3-mercaptopropionic acid (3-MP) treatment not only accelerated oxidant damage, but also induced cell death involving chromatin condensation, DNA ladder and cytochrome c releasing. Taken together, our present research indicated that exogenous GABA could alleviate the wound-induced oxidative stress and PCD occurrence in fresh-cut pumpkins.

ROS-Activated nanoscale coordination polymers for enhanced ultrasound-mediated therapy for the treatment of cancer

Stimuli-responsive nanoplatforms for efficient delivery of drugs in an on-demand manner show promising potential for killing cancer cells with high accuracy and minimal invasiveness. Herein, taking advantage of the good tissue-penetrating depth of sonodynamic therapy (SDT), reactive oxygen species (ROS)-responsive nanoscale coordination polymers (NCPs) were designed through self-assembly of porphyrins (PP) and platinum, which contained ROS-cleavable thioketal (TK) linkers to enhance the release of doxorubicin (Dox) during SDT. Upon exposure to the ultrasound (US), the Dox-loaded NCPs (PTK@PEG/Dox) could generate high amounts of cytotoxic ROS and heat, which not only induced the apoptosis of MCF-7 cells but also facilitated the efficient release of Dox due to the decomposition of the ROS-sensitive TK linkers, achieving the synergistic therapy of US-induced therapy and chemotherapy. After being modified with Arg-Gly-Asp (RGD) peptide, RGD/PTK@PEG exhibited a good targeting ability to cancer cells. Importantly, using the multicellular tumor spheroids (MCTS) derived from MCF-7 cells as a model, the RGD/PTK@PEG/Dox exhibited an efficient and controlled release behavior of Dox under the US irradiation, accompanying a tremendous anti-cancer effect for inducing apoptosis in the solid tumor tissues. This work provided a potential strategy to design controllable and stimuli-responsive nanoplatforms for synergistic/enhanced US-induced cancer therapy. STATEMENT OF SIGNIFICANCE: Stimulus-responsive nanoplatforms can deliver drugs efficiently in an on-demand manner, showing the potential to kill cancer cells with high accuracy and minimal invasiveness. Taking advantage of the good penetration ability of ultrasound (US), nanoscale coordination polymers (NCP) composed of porphyrin (PP), thioketal (TK) linkers, and platinum(II) were prepared via a coordination-driven self-assembly procedure. After doxorubicin (Dox) was loaded on the NCP (PTK@PEG/Dox), the nanoplatform responded to reactive oxygen species (ROS) under the stimulation of US, and induced the on-demand release of Dox, thereby achieving the combined therapeutic effect of sonodynamic therapy (SDT) and chemotherapy for cancer. This work provides a potential strategy for the development of controllable and stimuli-responsive nanoplatforms for enhanced ultrasound-induced cancer therapy.

Metal-Organic Gel-Modulated Synthesis of Hierarchically Porous Molecularly Imprinted Polymers for Efficient Removal of Sildenafil from Water

Molecularly imprinted polymers (MIPs) with high specific recognition capability are promising in environmental remediation. However, traditional MIPs usually show poor specific binding affinity toward templates in pure aqueous medium, thus greatly limiting their practical applications in wastewater treatment. Herein, we proposed a facile and versatile method to synthesize a water-compatible hierarchically porous MIP (HP-MIP), in which a metal-organic gel (MOG) was formed by in situ assembly and acted as a removable structural modulator. Remarkably, the integration of the MOG modulator and template imprinting defects significantly improved the specific template binding affinity of HP-MIP in water. The adsorption behavior of HP-MIP fitted well with the heterogeneous Freundlich isotherm, suggesting that HP-MIP possessed greater site heterogeneity to sildenafil than HP-NIP, which confirmed the efficiency of HP-MIP for the removal of sildenafil from water. This approach provides an important pathway to prepare water-compatible porous MIP for efficient removal of highly toxic organic pollutants from wastewater.

Polymer Networks Synthesized from Poly(Sorbitol Adipate) and Functionalized Poly(Ethylene Glycol)

Polymer networks were prepared by Steglich esterification using poly(sorbitol adipate) (PSA) and poly(sorbitol adipate)-graft-poly(ethylene glycol) mono methyl ether (PSA-g-mPEG12) copolymer. Utilizing multi-hydroxyl functionalities of PSA, poly(ethylene glycol) (PEG) was first grafted onto a PSA backbone. Then the cross-linking of PSA or PSA-g-mPEG12 was carried out with disuccinyl PEG of different molar masses (Suc-PEGn-Suc). Polymers were characterized through nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). The degree of swelling of networks was investigated through water (D2O) uptake studies, while for detailed examination of their structural dynamics, networks were studied using 13C magic angle spinning NMR (13C MAS NMR) spectroscopy, 1H double quantum NMR (1H DQ NMR) spectroscopy, and 1H pulsed field gradient NMR (1H PFG NMR) spectroscopy. These solid state NMR results revealed that the networks were composed of a two component structure, having different dipolar coupling constants. The diffusion of solvent molecules depended on the degree of swelling that was imparted to the network by the varying chain length of the PEG based cross-linking agent.

Multielement Synergetic Effect of Boron Nitride and Multiwalled Carbon Nanotubes for the Fabrication of Novel Shape-Stabilized Phase-Change Composites with Enhanced Thermal Conductivity

Shape-stabilized phase-change composites (SSPCCs) have been widely applied for thermal energy storage and thermal management because of their excellent properties. To further improve their thermal conductivity and thermal cycling stability, we successfully designed and synthesized a series of SSPCCs with three-dimensional (3D) thermally conductive networks by exploiting the synergistic effect between one-dimensional (1D) carbon nanotubes (CNTs) and two-dimensional (2D) hexagonal boron nitride (h-BN). The interconnected thermally conductive network composed of h-BN and multiwalled carbon nanotubes (MWCNTs) enhanced the SSPCC performance. The micromorphologies of the prepared SSPCCs revealed that well-dispersed MWCNTs, hydroxylated h-BN, and polyethylene glycol (PEG) molecular chains effectively bonded into a 3D cross-linking structure of the SSPCCs. Moreover, the chemical and crystalline structural and thermal properties and thermal cycling stability of the novel SSPCCs were systematically investigated by various characterization techniques. The presence of a 3D thermally conductive network in the as-synthesized SSPCCs evidently improved the shape stability, phase-change behavior, and thermal stability. Benefiting from the 3D nanostructural uniqueness of SSPCCs, the thermal conductivity of SSPCC-2 was up to 1.15 W m^-1 K^-1, which represented a significant enhancement of 239.7% compared with that of pure PEG. Meanwhile, the efficient synergistic effect of h-BN and MWCNTs remarkably enhanced the heat-transfer rate of the SSPCCs. These results demonstrate that the prepared SSPCCs have potential for applications in thermal energy storage and thermal management systems. This study opens a new avenue toward the development of SSPCCs with good comprehensive properties.

One-step synthesis of Cu(II) metal-organic gel as recyclable material for rapid, efficient and size selective cationic dyes adsorption

Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic. Herein, a rationally designed a Cu(II)-based metal-organic gel (Cu-MOG) with a nanoporous 3D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes. The Cu-MOG exhibited high efficiency, with an adsorption capacity of up to 650.32 mg/g, and rapid adsorption efficiency, with the ability to adsorb 80% of Neutral Red within 1 min. The high adsorption efficiency was attributed to its large specific surface area, which enabled it to massively bind cationic dyes through electrostatic interaction, and a nanoporous structure that promoted intra-pore diffusion. Remarkably, the Cu-MOG displayed size-selective adsorption, based on adsorption studies concerning dyes of different sizes as calculated by density functional theory. Additionally, the adsorption performance of the Cu-MOG still maintained removal efficiency of 100% after three regeneration cycles. These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.