RESUMO
Plastic recycling is critical for dematerializing of plastics. It has a profound implication on decoupling economic growth from environmental pressure and advancing waste plastic governance domestically and internationally while identifying drivers that might improve decoupling. In this study, plastic consumption and recycling patterns are presented, and the factors influencing the acceleration of dematerialization subsequent to the ban were investigated in the G7 countries and China. The results show that plastic consumption increases from 7.60 million metric tons (mt) to 12.60 mt between 2017 and 2019, and subsequently rapidly decreases to 6.84 mt in 2020. The plastic recycling rate drastically decreased by 21.3% in 2017, and decreased slightly from 2017 to 2020, at an annual rate of 2.9% on average. China's ban shocked the decoupling trends, which showed resilience and motivated the development of robust plastic recycling, and the global recycling transformation pattern accelerated the dematerialization of plastics. Decoupling performances of the G7 and China gradually stabilized in 2019, and all the countries were strongly decoupled in 2020, although decoupling index (DI) fluctuates from 2017 to 2020. Among the recycling-trading drivers, the improvement of waste plastic quality in recycling contributes more to decoupling, the recycling rate shows a more negative decoupling effect on China before the ban, and the population effect is weak relative to other influencing factors. The factors revealed the mechanism of decoupling of plastic consumption in the recycling-trading process, and the recyclability improvement in terms of plastic quality is important for dematerialization.
Assuntos
Desenvolvimento Econômico , Plásticos , China , ReciclagemRESUMO
In general, the traditional impedimetric aptasensor for detecting protein is based on its high molecular weight and low dielectric constant. Yet, the efficiency of these aptasensors is hindered by the slight resistance change in the trace concentration range because of the high initial resistance (the electrostatic repulsion between the compact negatively charged DNA on the electrode and [Fe(CN)6]3-/4-). To effectively and simply circumvent this issue and improve the detection sensitivity, we design an impedimetric aptasensor by reducing the substrate DNA's density on the electrode through the target-inspired recycling DNA cleavage. In order to enlarge the differences in resistance, the polyacrylic acid (PAA) nanogel is implemented as amplifier due to its poor conduction and negative charge that can hinder electron transfer and repulse the mediator [Fe(CN)6]3-/4-, respectively. Based on the target-inspired DNAzyme and PAA nanogel as amplifier, the ultrasensitive impedimetric aptasensor of carcinoembryonic antigen (CEA) in the buffer solution possesses a wide dynamic range of 10â¯fgâ¯mL-1 to 10â¯ngâ¯mL-1 and ultra-low detection limit of 7.9â¯fgâ¯mL-1 (10-fold relative to equivalent aptasensors). When tested in human serum, the proposed aptasensor exhibits good performance with an ultra-low detection limit of 1.4â¯fgâ¯mL-1, which is slightly higher than that in buffer solution.
Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Antígeno Carcinoembrionário/isolamento & purificação , Técnicas Eletroquímicas , Alanina/análogos & derivados , Alanina/química , Antígeno Carcinoembrionário/sangue , Antígeno Carcinoembrionário/química , DNA Catalítico/química , Ouro/química , Humanos , Nanopartículas Metálicas/química , Nanogéis , Polietilenoglicóis/química , Polietilenoimina/química , Zinco/químicaRESUMO
Multidrug resistance (MDR) is a major obstacle for the clinical therapy of malignant human cancers. The discovery of RNA interference provides efficient gene silencing within tumor cells for reversing MDR. In this study, a new "binary polymer" low-density lipoprotein-N-succinyl chitosan-cystamine-urocanic acid (LDL-NSC-SS-UA) with dual pH/redox sensitivity and targeting effect was synthesized for the co-delivery of breast cancer resistance protein small interfering RNA (siRNA) and paclitaxel (PTX). In vivo, the co-delivering micelles can accumulate in tumor tissue via the enhanced permeability and retention effect and the specific recognition and combination of LDL and LDL receptor, which is overexpressed on the surface of tumor cell membranes. The siRNA-PTX-loaded micelles inhibited gene and drug release under physiological conditions while promoting fast release in an acid microenvironment or in the presence of glutathione. The micelles escaped from the lysosome through the proton sponge effect. Additionally, the micelles exhibited superior antitumor activity and downregulated the protein and mRNA expression levels of breast cancer resistance protein in MCF-7/Taxol cells. The biodistribution and antitumor studies proved that the siRNA-PTX-loaded micelles possessed prolonged circulation time with a remarkable tumor-targeting effect and effectively inhibited tumor growth. Therefore, the novel dual pH/redox-sensitive polymers co-delivering siRNA and PTX with excellent biocompatibility and effective reversal of MDR demonstrate a considerable potential in cancer therapy.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Portadores de Fármacos/química , Paclitaxel/administração & dosagem , Polímeros/química , RNA Interferente Pequeno/administração & dosagem , Animais , Linhagem Celular Tumoral , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/farmacocinética , Liberação Controlada de Fármacos , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Feminino , Humanos , Concentração de Íons de Hidrogênio , Lipoproteínas LDL , Células MCF-7/efeitos dos fármacos , Camundongos Nus , Micelas , Oxirredução , Paclitaxel/química , Paclitaxel/farmacocinética , Polímeros/administração & dosagem , Interferência de RNA , RNA Interferente Pequeno/genética , Distribuição TecidualRESUMO
Malignant proliferation and metastasis in non-small cell lung carcinoma (NSCLC) are great challenges for effective clinical treatment through conventional chemotherapy. The combinational therapy strategy of RNA interfering (RNAi) technology and chemotherapeutic agents have been reported to be promising for effective cancer therapy. In this study, based on multifunctional nanoparticles (NPs), the simultaneous delivery of etoposide (ETP) and anti-Enhancer of Zeste Homologue 2 (EZH2) siRNA for the effective treatment of orthotopic lung tumor was achieved. The NPs exhibited pH/redox dual sensitivity verified by particle size changes, morphological changes, and in vitro release of drugs. Confocal microscopy analysis confirmed that the NPs exhibited endosomal escape property and on-demand intracellular drug release behavior, which can protect siRNA from degradation and facilitate the chemotherapeutic effect respectively. In vitro tumor cell motility study demonstrated that EZH2 siRNA loaded in NPs can decrease the migration and invasion capabilities of tumor cells by downregulating the expression of EZH2 mRNA and protein. In particular, an antiproliferation study revealed that the co-delivery of siRNA and ETP in the multifunctional NPs can induce a synergistic therapeutic effect on NSCLC. In vivo targeting evaluation showed that cRGDyC-PEG modification on NPs exhibited a low distribution in normal organs and an obvious accumulation in orthotopic lung tumor. Furthermore, targeted NPs co-delivering siRNA and ETP showed superior inhibition on tumor growth and metastasis and produced minimal systemic toxicity. These findings indicated that multifunctional NPs can be utilized as a co-delivery system, and that the combination of EZH2 siRNA and ETP can effectively treat NSCLC.
Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Etoposídeo/administração & dosagem , Nanopartículas/administração & dosagem , RNA Interferente Pequeno/administração & dosagem , Células A549 , Animais , Antineoplásicos Fitogênicos/química , Apoptose/efeitos dos fármacos , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Ciclo Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Terapia Combinada , Liberação Controlada de Fármacos , Etoposídeo/química , Feminino , Humanos , Camundongos Nus , Nanopartículas/química , Polímeros/administração & dosagem , Polímeros/química , RNA Interferente Pequeno/químicaRESUMO
In this study, harmine liposomes (HM-lip) were prepared through the thin-film hydration-pH-gradient method and then coated with N-trimethyl chitosan (TMC). Particle size, zeta potential, entrapment efficiency, and in vitro release of HM-lip and TMC-coated harmine liposomes (TMC-HM-lip) were also determined. Sprague Dawley rats were further used to investigate the pharmacokinetics in vivo. Retention behavior in mouse gastrointestinal tract (GIT) was studied through high-performance liquid chromatography and near-infrared imaging. Degradation was further evaluated through incubation with Caco-2 cell homogenates, and a Caco-2 monolayer cell model was used to investigate the uptake and transport of drugs. HM-lip and TMC-HM-lip with particle size of 150-170 nm, an entrapment efficiency of about 81%, and a zeta potential of negative and positive, respectively, were prepared. The release of HM from HM-lip and TMC-HM-lip was slower than that from HM solution and was sensitive to pH. TMC-HM-lip exhibited higher oral bioavailability and had prolonged retention time in GIT. HM-lip and TMC-HM-lip could also protect HM against degradation in Caco-2 cell homogenates. The uptake amount of TMC-HM-lip was higher than that of HM and HM-lip. TMC-HM-lip further demonstrated higher apparent permeability coefficient (P(app)) from the apical to the basolateral side than HM and HM-lip because of its higher uptake and capability to open tight junctions in the cell monolayers. TMC-HM-lip can prolong the retention time in the GIT, protect HM against enzyme degradation, and improve transport across Caco-2 cell monolayers, thus enhancing the oral bioavailability of HM.
Assuntos
Quitosana/química , Trato Gastrointestinal/efeitos dos fármacos , Harmina/metabolismo , Lipossomos/química , Administração Oral , Animais , Disponibilidade Biológica , Células CACO-2 , Permeabilidade da Membrana Celular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Portadores de Fármacos/química , Trato Gastrointestinal/citologia , Trato Gastrointestinal/metabolismo , Humanos , Técnicas In Vitro , Lipossomos/administração & dosagem , Camundongos , Tamanho da Partícula , Ratos , Ratos Sprague-DawleyRESUMO
Interfacial interactions involved in reverse osmosis (RO) membrane fouling by humic acid were quantitatively evaluated using the XDLVO (extended Derjaguin-Landau-Verwey-Overbeek) approach. The role of each individual interfacial interaction during membrane fouling was elucidated with special emphasis devoted into the influence of Ca2+ under different solution pHs. The results showed that, regardless of the presence of Ca2+, van der Waals interaction favoring fouling contributed the most to the interfacial interactions at pH 3, whereas the polar interaction inhibiting fouling played a dominant role at pH 7 and pH 10. Electrostatic double layer interaction appeared to be the weakest in all cases, thus contributing the least to membrane fouling. It was the changing of polar interaction that gave rise to the influence of Ca2+ on membrane fouling, which turned out to be more significant at lower pH. Ca2+ would accelerate humic acid RO membrane fouling at most cases. Correlation analysis between interfacial free energy and fouling extent revealed that XDLVO approach could reasonably predict humic acid RO membrane fouling behaviors under different solution conditions.