Jin Zhang,Hui Zeng,Wenshan Liang,Honghua Hu,Michael C. Breadmore,Min Zhang
Capillary electrophoresis (CE) is increasingly used in distributed field environmental monitoring, teaching, and citizen science. Consequently, the development of low-cost CE instruments using inexpensive components and do-it-yourself approaches has gained significant attention. Peristaltic micro-pumps (PMPs), with dimensions as small as 15 × 17 × 34 mm 3 , offer advantages such as low cost, compact size, and energy efficiency, making them highly suitable for miniaturized CE instruments with automated flow-through injection. This study presents the development and application of a closed-loop PMP integrated into a CE system to enhance flow-through injection precision and analytical performance. The closed-loop control design incorporates a Hall sensor to monitor pump rotor positions, ensuring stable operation. The modified PMP achieved a pressure relative standard deviation (RSD) of 0.7% ( n = 10), representing a threefold improvement over time-based and back electromotive force feedback controls. The system was applied to detect common cations and anions in drinking water. Experimental validation confirmed the reliability and precision of the CE system, with injection RSDs below 4.0% ( n = 42 for anions and 58 for cations). The calibration ranges were 0–500 μM with R 2 values ≥ 0.994. Detection limits ranged from 0.9 to 3.6 μM. The RSDs ( n = 10) of peak heights for ions in tap water were between 1.1% and 7.7%. Additionally, the CE system was employed to analyze total nitrogen and total phosphorus in water following persulfate oxidation. The total cost of the system was estimated to be approximately 6000 USD, including a ∼4000 USD TraceDec contactless conductivity detector. These findings demonstrate that the modified CE system with a closed-loop PMP significantly enhances injection precision, analytical performance, and versatility for environmental ion and nutrient detection. This system provides a reliable and cost-effective tool for on-site water quality monitoring.
The construction of heterojunction systems is an effective way to efficiently generate hydrogen by water photolysis. In this work, Ni-MOF (trimesic acid, (BTC)) and g-C 3 N 4 (denoted as CN) were combined, and then Ni-MOF/CN was modified by 4-Methyl-5-vinyl thiazole (denoted as MVTh). Finally, CdS was loaded on the surface of Ni-MOF/CN/MVTh to prepare the photocatalyst Ni-MOF/g-C 3 N 4 /MVTh/CdS (denoted as Ni/CN/M/Cd) with a triangular closed-loop path heterojunction for the first time. As a photocatalyst without precious metal cocatalysts, Ni/CN/M/Cd displayed high H 2 evolution (17.844 mmol·g −1 ·h −1 ) under an optimum CdS loading of 40 wt%. The H 2 evolution rate was approximately 79 times that of Ni-MOF/CN and exceeded those of almost all catalysts based on MOF/CN in the literature. The triangular closed-loop heterojunction formed between Ni-MOF, g-C 3 N 4 , and CdS could realize the directional migration of photocarriers and significantly diminished the transfer resistance of carriers. The Ni 2+ in Ni-MOF provided many cocatalytic sites for H 2 evolution via g-C 3 N 4 and CdS. Furthermore, charge carrier separation in Ni-MOF/CN/CdS improved after the innovative addition of MVTh. This study provides a reference for the construction of a closed-loop heterojunction system without precious metal cocatalysts.
Multi-modal combination therapy for tumors can overcome the limitations of single-modal therapy and bring new opportunities for high-efficient tumor treatment. Nevertheless, how to ingeniously design functionalized nanocarriers to mediate the synergistict effects among various therapeutic approaches remains a core challenge. In this study, we developed a polydopamine (PDA) coated outside and glucose oxidase (GOx) adsorbed inside copper-doped zeolitic imidazolate framework-8 (CZ8) with metformin hydrochloride (MET) / doxorubicin (DOX) as a multifunctional nano-codelivery system, abbreviated as PMDGCZ8, which could focus more on the synergy and continuity of multiple therapies including photothermal therapy (PTT), chemodynamic therapy (CDT), starving tumor therapy (STT) and chemotherapy (CT). Herein, PMDGCZ8 innovatively combined the gating effect of PDA membrane with the pH sensitivity of CZ8 skeleton to form a dual-responsive bomb that could trigger release on demand and significantly improve the accuracy of tumor localization. Furthermore, we also incorporated the strategies of reshaping the tumor hypoxia and immunosuppressive microenvironment into the synergistic treatment process in order to achieve a comprehensive anti-tumor ecological network. Both in vitro and in vivo experiments suggested that PMDGCZ8 significantly enhanced drug accumulation on tumors, reduced systemic toxicity, activated anti-tumor immune response, further inhibited the recurrence and metastasis, and consequently was expected to become a new type of nano-delivery platform with great development potential.
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