Mass-spectrometry-based and X-ray fluorescence-based techniques have allowed the study of the distribution of Zn²⁺ ions at extracellular and intracellular levels over the past few years. However, there are some issues during purification steps, sample preparation, suitability for quantification, and the instruments’ availability. Therefore, work on fluorescent sensors based on 8-aminoquinoline as tools to detect Zn²⁺ ions in environmental and biological applications has been popular. Introducing various carboxamide groups into an 8-aminoquinoline molecule to create 8-amidoquinoline derivatives to improve water solubility and cell membrane permeability is also a recent trend. This review aims to present a general overview of the fluorophore 8-aminoquinoline and its derivatives as Zn²⁺ receptors for zinc sensor probes. Various fluorescent chemosensor designs based on 8-amidoquinoline and their effectiveness and potential as a recognition probe for zinc analysis were discussed. Based on this review, it can be concluded that derivatives of 8-amidoquinoline have vast potential as functional receptors for zinc ions primarily because of their fast reactivity, good selectivity, and bio-compatibility, especially for biological applications. To better understand the Zn²⁺ ion fluorophores’ function, diversity of the coordination complex and geometries need further studies. This review provides information in elucidating, designing, and exploring new 8-amidoquinoline derivatives for future studies for the improvement of chemosensors that are selective and sensitive to Zn²⁺.

Sepsis remains a global health emergency, demanding timely and accurate diagnostics to reduce morbidity and mortality. This review critically assesses the recent progress (2020–2025) in the development of electrochemical aptamer-based biosensors for sepsis detection. These biosensors combine aptamers’ high specificity and modifiability with the sensitivity and miniaturization potential of electrochemical platforms. The analysis highlights notable advances in detecting key sepsis biomarkers, such as C-reactive protein (CRP), procalcitonin (PCT), interleukins (e.g., interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)), lipopolysaccharides (LPSs), and microRNAs using diverse sensor configurations, including a field-effect transistor (FET), impedance spectroscopy, voltammetry, and hybrid nanomaterial-based systems. A comparative evaluation reveals promising analytical performance in terms of the limit of detection (LOD), rapid response time, and point-of-care (POC) potential. However, critical limitations remain, including variability in validation protocols, limited testing in real clinical matrices, and challenges in achieving multiplexed detection. This review underscores translational barriers and recommends future directions focused on clinical validation, integration with portable diagnostics, and interdisciplinary collaboration. By consolidating current developments and gaps, this work provides a foundation for guiding next-generation biosensor innovations aimed at effective sepsis diagnosis and monitoring.

The environmental contamination by extremophile Aspergillus species, i.e., Aflatoxin B1, is hardly controllable in Southeast Asia and Sub-Saharan Africa, which lack handling resources and controlled storage facilities. Acute aflatoxicosis poisoning from aflatoxin-prone dietary staples could cause acute hepatic necrosis, acute liver failure, and death. Here, as the cheaper, more straightforward, and facile on-site diagnostic kit is needed, we report an ultraviolet-excitable optical aptasensor based on a fluorinated ethylene propylene film strip. Molecular dynamics on the aptamer.AFB1 complex revealed that the AFB1 to the aptamer increases the overall structural stability, suggesting that the aptamer design is suitable for the intended application. Under various influencing factors, the proposed label-free strategy offers a fast 20-min on-site fabrication simplicity and 19-day shelf-life. The one-pot incubation provides an alternative to catalytic detection and exhibited 4 times reusability. The recovery of crude brown sugar, processed peanuts, and long-grain rice were 102.74 ± 0.41 (n = 3), 86.90 ± 3.38 (n = 3), and 98.50 ± 0.42 (n = 3), comparable to High-Performance Liquid Chromatography-Photodiode Array Detector results. This study is novel owing to the peculiar UV-active spectrum fingerprint and the convenient use of hydrophobic film strips that could promote breakthrough innovations and new frontiers for on-site/forensic detection of environmental pollutants.

Zinc has been demonstrated to boost immune response during SAR-CoV-2 infection, where it prevents coronavirus multiplication. Clinical investigations have testified to its beneficial effects on respiratory health and its deficiency may reduce immune function. A highly sensitive detection of Zn(II) ion via differential pulse voltammetry (DPV) utilizing an environmentally friendly modified screen-printed carbon electrode (SPCE) of electrochemically reduced graphene oxide (ErGO) embedded with carboxylated-8-carboxamidoquinoline (CACQ) as Zn(II) chelating ligand. The green CACQ/ErGO-modified SPCE was characterized by spectroscopy techniques, such as Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and field-emission scanning electron microscopy with energy dispersive X-ray (FESEM-EDX). The modified electrode-solution interface was studied by electrochemical cyclic voltammetry (CV) and DPV methods. The CACQ-modified wrinkled ErGO electrode conferred a large surface-to-volume ratio with multiple binding sites resulting in greater opportunity for multiple dative covalent binding events with Zn(II) via coordination chemistry, and considerably accelerated the electron transfer rate at the electrode surface. The green Zn(II) sensor demonstrated a quick response time (60 s), broad linear range [1 pM-1 μM Zn(II) ion], a limit of detection (LOD) of 0.53 pM, 35 days of storage period (≥80% of its initial response retained), good reproducibility [relative standard deviation (RSD) = 3.4%], and repeatability (RSD = 4.4%). The developed electrode was applied to determine Zn(II) ion concentration in dietary supplement samples, and the results were in good agreement with those obtained from inductively coupled plasma-mass spectrometry (ICP-MS).