A microdots array-based fluoremetric assay with superwettability profile for simultaneous and separate analysis of iron and copper in red wine

Developments, challenges and future trends in advanced sustainable machining technologies for preparing array micro-holes

The use of array micro-holes is becoming increasingly prevalent across a range of industries, including the aerospace, automotive, electronics, medical and chemical industries. The utilization of advanced sustainable machining technologies offers distinctive advantages and is pivotal for the sustainable manufacture of array micro-holes. This paper examines the sustainable machining techniques commonly employed in the production of array micro-holes, including electrical discharge machining, laser machining, electrochemical machining and composite machining technologies. The paper begins with an elaboration of the processing principles and characteristics of multiple non-traditional machining techniques. The performance indicators of the most commonly used processing technologies in industrial production are summarized from seven perspectives. Six significant avenues for the advancement of sustainable manufacturing technology for array micro-holes have been identified and categorized. This article provides a summary and evaluation of the previous relevant literature, with the aim of offering guidance for the development of array micro-hole processing technologies.

Colorimetric detection of electrolyte ions in blood based on biphasic microdroplet extraction

BACKGROUND

Timely diagnosis and prevention of diseases require rapid and sensitive detection of biomarkers from blood samples without external interference. Abnormal electrolyte ion levels in the blood are closely linked to various physiological disorders, including hypertension. Therefore, accurate, interference-free, and precise measurement of electrolyte ion concentrations in the blood is particularly important.

RESULTS

In this work, a colorimetric sensor based on a biphasic microdroplet extraction is proposed for the detection of electrolyte ions in the blood. This sensor employs mini-pillar arrays to facilitate contact between adjacent blood microdroplets and organic microdroplets serving as sensing phases, with any color changes being monitored through a smartphone's colorimetric software. The sensor is highly resistant to interference and does not require pre-treatment of the blood samples. Remarkably, the sensor exhibits exceptional reliability and stability, allowing for rapid enrichment and detection of K+, Na+, and Cl- in the blood within 10 s (Cl-), 15 s (K+) and 40 s (Na+) respectively.

SIGNIFICANCE

The colorimetric sensor based on biphasic microdroplet extraction offers portability due to its compact size and ease of operation without the need for large instruments. Additionally, it is location-independent, making it a promising tool for real-time biomarker detection in body fluids such as blood.

Combined fabrication of zeolitic imidazolate framework-8 and lanthanide towards coordination polymers: A dual-signal fluorescent probe for sensing Cu2+ based on synergistic effect of aggregation-induced emission and antenna effect

Copper ion (Cu2+) detection remains an important task for monitoring water quality because of its specific toxicity. Herein, a new dual-signal fluorescent probe was developed by combining zeolitic imidazolate framework-8 (ZIF-8) and lanthanide for the detection of Cu2+ for the first time. The lanthanide coordination polymer (guanosine monophosphate and Eu3+, GMP/Eu) was initially incorporated into ZIF-8 to yield ZIF-8/GMP/Eu nanomaterials with extremely weak single emission fluorescence at 618 nm. It was found that the resulted nanomaterials could display a dual emission fluorescence at 515 nm and 618 nm after the introduction of tetracycline (TC) due to the synergistic effect of aggregation-induced emission effect (AIE, TC induced by ZIF-8) and antenna effect (AE, between TC and GMP/Eu). Interestingly, in the presence of Cu2+, the AIE of TC was destroyed because of the interaction of Cu2+ with ZIF-8 and TC. The AE between TC and GMP/Eu disappeared due to the formation of complex between TC and Cu2+. A dual-signal fluorescent probe of ZIF-8/GMP/Eu/TC was thereby established for sensing Cu2+ in the range of 0.5-100 μM. Such a dual-signal response strategy that intelligently utilized the "ON"/"OFF" of AIE and AE can not only eliminate the background interference, but also ensure the improved selectivity of Cu2+ sensing. Subsequently, the dual-signal fluorimetric strategy was applied for the detection of Cu2+ in environmental water samples, indicating the potential feasibility of applications for water quality monitoring.

Sensitive fluorescence ELISA for the detection of zearalenone based on self-assembly DNA nanocomposites and copper nanoclusters

Zearalenone (ZEN), produced by Fusarium species, is a potential risk to human health. Traditional enzyme-linked immunosorbent assay (ELISA) is restricted due to low sensitivity for the detection of ZEN. Herein, enzyme nanocomposites (ALP-SA-Bio-ssDNA, ASBD) were prepared with the self-assembly strategy based on streptavidin-labeled alkaline phosphatase (SA-ALP) and dual-biotinylated ssDNA (B2-ssDNA). The enzyme nanocomposites improved the loading amount of ALP and catalyzed more ascorbic acid 2-phosphate to generate ascorbic acid (AA). Subsequently, Cu2+ could be reduced to copper nanoclusters (CuNCs) having strong fluorescence signal by AA with poly T. Benefiting from the high enzyme load of nanocomposites and the strong signal of CuNCs, the fluorescence ELISA was successfully established for the detection of ZEN. The proposed method exhibited lower limit of detection (0.26 ng mL-1) than traditional ELISA (1.55 ng mL-1). The recovery rates ranged from 92.00% to 108.38% (coefficient of variation < 9.50%) for the detection of zearalenone in corn and wheat samples. In addition, the proposed method exhibited no cross reaction with four other mycotoxins. This proposed method could be used in trace detection for food safety.

Development of a highly sensitive fluorescent probe using Delonix regia (Gulmohar) tree pod shell for precise sarcosine detection in human urine samples: advancing prostate cancer diagnosis

We designed a highly sensitive fluorescent sensor for the early detection of sarcosine, a potential biomarker for prostate cancer. This sensor was based on surface-cobalt-doped fluorescent carbon quantum dots (Co-CD) using a FRET-based photoluminescent sensing platform. Blue luminescent carbon quantum dots (CQD) were synthesised through a hydrothermal approach, utilizing Delonix regia tree pod shells. Cobalt was employed to functionalize the CQD, enhancing the quantum-entrapped effects and minimizing surface flaws. To optimize Co-CD preparation, we employed a Box-Behnken design (BBD), and response surface methodology (RSM) based on single-factor experiments. The Co-CD was then used as a fluorescent probe for selective Cu2+ detection, with Cu2+ quenching Co-CD fluorescence through an energy transfer process, referred to as 'turn-off'. When sarcosine was introduced, the fluorescence intensity of Co-CD was restored, creating a 'turn-on' response. The sensor exhibited a Cu2+ detection limit (LOD) of 2.4 µM with a linear range of 0 μM to 10 µM. The sarcosine detection in phosphate buffer saline (PBS, pH 7.4) resulted in an LOD of 1.54 μM and a linear range of 0 to 10 µM. Importantly, the sensor demonstrated its suitability for clinical analysis by detecting sarcosine in human urine. In summary, our rapid and highly sensitive sensor offers a novel approach for the detection of sarcosine in real samples, facilitating early prostate cancer diagnosis.

Fluorescent covalent organic frameworks for environmental pollutant detection sensors and enrichment sorbents: a mini-review

Covalent organic frameworks (COFs) are a class of porous crystalline materials based on organic building blocks containing light elements, such as C, H, O, N, and B, interconnected by covalent bonds. Because of their regular crystal structure, high porosity, stable mechanical structure, satisfactory specific surface area, easy functionalization, and high tunability, they have important applications in several fields. Currently, most of the established methods based on COFs can only be used for individual detection or adsorption of the target. Impressively, fluorescent COFs as a special member of the COF family are able to achieve highly selective and sensitive detection of target pollutants by fluorescence enhancement or quenching. The construction of a dual-functional platform for detection and adsorption based on fluorescent COFs can enable the simultaneous realization of visual monitoring and adsorption of target pollutants. Therefore, this paper reviews the research progress of fluorescent COFs as fluorescence sensors and adsorbents. First, the fluorescent COFs were classified according to the different bonding modes between the building blocks, and then the applications of fluorescent COF-based detection and adsorption bifunctional materials for various environmental contaminants were highlighted. Finally, the challenges and future application prospects of fluorescent COFs are discussed.

Fluorescence detection of 4-nitrophenol and α-glucosidase activity based on 4-nitrophenol-regulated fluorescence of silicon nanoparticles

A fluorescence assay for the detection of 4-nitrophenol (4-NP), α-glucosidase (α-Glu) activity and α-Glu inhibitors (AGIs) is developed based on the inner filter effect (IFE), a flexible and simple signal transfer strategy. In this assay, silicon nanoparticles (Si NPs) synthesized under mild and easily accessible conditions are employed as fluorescent indicators. 4-NP efficaciously quenches the fluorescence of Si NPs through the IFE at a very rapid rate, thus achieving 4-NP detection in a mix-to-read manner, which is suitable for on-site detection. The quenching mechanism has been comprehensively studied and confirmed. More significantly, based on the fact that 4-NP can be generated through α-Glu-catalyzed hydrolysis of 4-nitrophenyl-α-D-glucopyranoside (NPG), the fluorescence detection of α-Glu activity is legitimately achieved by employing NPG as the substrate. The linear ranges for 4-NP and α-Glu activity detection are 0.5-60 μM and 0.5-60 mU mL-1 with low detection limits of 0.074 μM and 0.094 mU mL-1, respectively. This method not only can preciously assay targets in real samples, but is also capable of screening AGIs as drugs as well as assessing their inhibition efficiency.