Matrix metalloproteinase-1 (MMP-1) is associated with many types of cancers, including oral, colorectal, and brain cancers. This paper describes the fabrication of an MMP-1 immunosensor based on a gold nanoparticle/polyethyleneimine/reduced graphene oxide (AuNP/PEI/rGO)-modified disposable screen-printed electrode (SPE). A microwave-assisted single-step method was employed for the simultaneous reduction of gold and graphene oxide in a PEI environment to avoid AuNP agglomeration. The crystal structure, chemical composition, optical properties, and interior morphology of the materials were probed by X-ray diffraction, Raman spectroscopy, UV-visible spectrometry, and transmission electron microscopy techniques. To assemble a label-free MMP-1 immunosensor layer-by-layer, 3-mercaptopropionic acid was utilized due to its strong sulfur-gold bonding ability, and its tail end was attached to a carboxyl group, allowing the MMP-1 antibody (anti-MMP-1) to be subsequently cross-linked using the traditional N-(3-dimethylaminopropyl) and N′ ethylcarbodiimide hydrochloride method. Differential pulse voltammetry analysis showed a linear relationship with MMP-1 concentration in the range of 1–50 ng ml⁻¹ with an R² value of ∼0.996 (n = 5, RSD < 5%). This immunosensor was successfully applied for MMP-1 detection in urine, saliva, bovine serum, and cell culture media (HSC-3 & C6) of oral and brain cancers showing results comparable to those of the credible ELISA method.

Herein, we present a one-pot hydrothermal approach for synthesizing metal–organic framework-derived copper (II) benzene-1,3,5-tricarboxylate (Cu-BTC) nanowires (NWs) using dopamine as the reducing agent and precursor for a polydopamine (PDA) surface coating formation. In addition, PDA can act as a PTT agent and enhance NIR absorption, producing photothermal effects on cancer cells. These NWs displayed a photothermal conversion efficiency of 13.32% after PDA coating and exhibited good photothermal stability. Moreover, NWs with a suitable T₁ relaxivity coefficient (r₁ = 3.01 mg⁻¹ s⁻¹) can be effectively used as magnetic resonance imaging (MRI) contrast agents. By increasing concentrations, cellular uptake studies showed a greater uptake of Cu-BTC@PDA NWs into cancer cells. Further, in vitro studies showed PDA-coated Cu-BTC NWs possess exceptional therapeutic performance by 808 nm laser irradiation, destroying 58% of cancer cells compared with the absence of laser irradiation. This promising performance is anticipated to advance the research and implementation of copper-based NWs as theranostic agents for cancer treatment.

Hydrogen sulfide (H₂S), an endogenous gasotransmitter, is produced in mammalian systems and is closely associated with pathological and physiological functions. Nevertheless, the complete conversion of H₂S is still unpredictable owing to the limited number of sensors for accurate and quantitative detection of H₂S in biological samples. In this study, we constructed a disposable electrochemical sensor based on PtNi alloy nanoparticles (PtNi NPs) for sensitive and specific in situ monitoring of H₂S released by human breast cancer cells. PtNi alloy NPs with an average size of 5.6 nm were prepared by a simple hydrothermal approach. The conversion of different forms of sulfides (e.g., H₂S, HS⁻, and S²⁻) under various physiological conditions hindered the direct detection of H₂S in live cells. PtNi NPs catalyze the electrochemical oxidation of H₂S in a neutral phosphate buffer (PB, pH 7.0). The PtNi-based sensing platform demonstrated a linear detection range of 0.013–1031 µM and the limit of detection was 0.004 µM (S/N = 3). Moreover, the PtNi sensor exhibited a sensitivity of 0.323 μA μM⁻¹ cm⁻². In addition, the stability, repeatability, reproducibility, and anti-interference ability of the PtNi sensor exhibited satisfactory results. The PtNi sensor was able to successfully quantify H₂S in pond water, urine, and saliva samples. Finally, the biocompatible PtNi electrode was effectively employed for the real-time quantification of H₂S released from breast cancer cells and mouse fibroblasts.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that are widely distributed in the environment. It is noteworthy that the PCBs are endocrine-disrupting substances, and their toxicity induces cancer and damage to the mammalian reproductive system, immune system, stomach, skin, liver, etc. This work aimed to synthesize 3A-amino-3A-deoxy-(2AS, 3AS)-β-cyclodextrin hydrate/tin disulfide composite material and to study its material properties, electrochemical properties, and application to PCB detection. The nanostructured tin disulfide (SnS₂) synthesized by hydrothermal technique and 3A-amino-3A-deoxy-(2AS, 3AS)-β-cyclodextrin hydrate were sequentially modified onto the disposable screen-printed carbon electrode (SPCE) via titration using a micropipette. The 3A-amino-3A-deoxy-(2AS, 3AS)-β-cyclodextrin hydrate (β-CD) improved the selectivity of the modified electrode. The fabricated β-CD/SnS₂/SPCE was employed to determine the presence of PCBs by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The detection range was 0.625–80 μM, with a limit detection of approximately 5 μM. The electrodes were as stable as 88% after 7 days’ storage. The results showed that the β-CD successfully encapsulated PCBs to achieve an electrochemical sensor that reduced the time and increased the convenience of PCBs detection.

Detecting pesticides using techniques that involve simple fabrication methods and conducting the detection at very low levels are challenging. Herein, we report the detection of acetamiprid at the quadrillionth level using surface-enhanced Raman scattering (SERS). The SERS chip comprises Ag nanoparticles deposited on a tetrapod structure of ZnO coated onto indium tin oxide glass (denoted as Ag@ZnO-ITO). Controlled Ag decoration of ZnO occurs via irradiation-induced synthesis. The morphology of the surface plays a significant role in achieving an enhanced SERS performance for acetamiprid detection. 4,4′-Dipyridyl (DPY) is used to investigate synthesis conditions for the chip, leading to an optimal irradiation time of 60 min. Furthermore, the enhancement factor for acetamiprid on Ag@ZnO-ITO is higher than 10⁷. These results demonstrate that SERS sensors have the potential for practical use in acetamiprid detection.