MoS2-based nanosensors in biomedical and environmental monitoring applications

Field effect transistor based wearable biosensors for healthcare monitoring

The rapid advancement of wearable biosensors has revolutionized healthcare monitoring by screening in a non-invasive and continuous manner. Among various sensing techniques, field-effect transistor (FET)-based wearable biosensors attract increasing attention due to their advantages such as label-free detection, fast response, easy operation, and capability of integration. This review explores the innovative developments and applications of FET-based wearable biosensors for healthcare monitoring. Beginning with an introduction to the significance of wearable biosensors, the paper gives an overview of structural and operational principles of FETs, providing insights into their diverse classifications. Next, the paper discusses the fabrication methods, semiconductor surface modification techniques and gate surface functionalization strategies. This background lays the foundation for exploring specific FET-based biosensor designs, including enzyme, antibody and nanobody, aptamer, as well as ion-sensitive membrane sensors. Subsequently, the paper investigates the incorporation of FET-based biosensors in monitoring biomarkers present in physiological fluids such as sweat, tears, saliva, and skin interstitial fluid (ISF). Finally, we address challenges, technical issues, and opportunities related to FET-based biosensor applications. This comprehensive review underscores the transformative potential of FET-based wearable biosensors in healthcare monitoring. By offering a multidimensional perspective on device design, fabrication, functionalization and applications, this paper aims to serve as a valuable resource for researchers in the field of biosensing technology and personalized healthcare.

Molybdenum Disulfide as Tunable Electrochemical and Optical Biosensing Platforms for Cancer Biomarker Detection: A Review

Cancer is a common illness with a high mortality. Compared with traditional technologies, biomarker detection, with its low cost and simple operation, has a higher sensitivity and faster speed in the early screening and prognosis of cancer. Therefore, extensive research has focused on the development of biosensors and the construction of sensing interfaces. Molybdenum disulfide (MoS2) is a promising two-dimensional (2D) nanomaterial, whose unique adjustable bandgap shows excellent electronic and optical properties in the construction of biosensor interfaces. It not only has the advantages of a high catalytic activity and low manufacturing costs, but it can also further expand the application of hybrid structures through different functionalization, and it is widely used in various biosensors fields. Herein, we provide a detailed introduction to the structure and synthesis methods of MoS2, and explore the unique properties and advantages/disadvantages exhibited by different structures. Specifically, we focus on the excellent properties and application performance of MoS2 and its composite structures, and discuss the widespread application of MoS2 in cancer biomarkers detection from both electrochemical and optical dimensions. Additionally, with the cross development of emerging technologies, we have also expanded the application of other emerging sensors based on MoS2 for early cancer diagnosis. Finally, we summarized the challenges and prospects of MoS2 in the synthesis, functionalization of composite groups, and applications, and provided some insights into the potential applications of these emerging nanomaterials in a wider range of fields.

Tumor-targeted molybdenum disulfide@barium titanate core-shell nanomedicine for dual photothermal and chemotherapy of triple-negative breast cancer cells

Combinational therapy can improve the effectiveness of cancer treatment by overcoming individual therapy shortcomings, leading to accelerated cancer cell apoptosis. Combinational cancer therapy is attained by a single nanosystem with multiple physicochemical properties providing an efficient synergistic therapy against cancer cells. Herein, we report a folate receptor-targeting dual-therapeutic (photothermal and chemotherapy) core-shell nanoparticle (CSNP) exhibiting a molybdenum disulfide core with a barium titanate shell (MoS₂@BT) to improve therapeutic efficacy against triple-negative breast cancer (TNBC) MDA-MB-231 cells. A simple hydrothermal approach was used to achieve the MoS₂@BT CSNPs, and their diameter was calculated to be approximately 180 ± 25 nm. In addition to improving the photothermal efficiency and stability of the MoS₂@BT CSNPs, their surface was functionalized with polydopamine (PDA) and subsequently modified with folic acid (FA) to achieve enhanced tumour-targeting CSNPs, named MoS₂@BT-PDA-FA (MBPF). Then, gemcitabine (Gem) was loaded into the MBPF, and its loading and releasing efficacy were calculated to be 17.5 wt% and 64.5 ± 3%, respectively. Moreover, the photothermal conversion efficiency (PCE) of MBPF was estimated to be 35.3%, and it also showed better biocompatibility, which was determined by an MTT assay. The MBPF significantly increased the ambient temperature to 56.3 °C and triggered Gem release inside the TNBC cells when exposed to a near-infrared (NIR) laser (808 nm, 1.5 W cm^-2, 5 min). Notably, the MoS₂@BT-based nanosystem was used as a photothermal agent and a therapeutic drug-loading container for combating TNBC cells. Benefiting from the combined therapy, MBPF reduced TNBC cell viability to 81.3% due to its efficient synergistic effects. Thus, the proposed tumour-targeting MoS₂@BT CSNP exhibits high drug loading, better biocompatibility, and improved anticancer efficacy toward TNBC cells due to its dual therapeutic approach in a single system, which opens up a new approach for dual cancer therapy.

MoS2 and MoS2 Nanocomposites for Adsorption and Photodegradation of Water Pollutants: A Review

The need for fresh and conveniently treated water has become a major concern in recent years. Molybdenum disulfide (MoS₂) nanomaterials are attracting attention in various fields, such as energy, hydrogen production, and water decontamination. This review provides an overview of the recent developments in MoS₂-based nanomaterials for water treatment via adsorption and photodegradation. Primary attention is given to the structure, properties, and major methods for the synthesis and modification of MoS₂, aiming for efficient water-contaminant removal. The combination of MoS₂ with other components results in nanocomposites that can be separated easily or that present enhanced adsorptive and photocatalytic properties. The performance of these materials in the adsorption of heavy metal ions and organic contaminants, such as dyes and drugs, is reviewed. The review also summarizes current progress in the photocatalytic degradation of various water pollutants, using MoS₂-based nanomaterials under UV-VIS light irradiation. MoS₂-based materials showed good activity after several reuse cycles and in real water scenarios. Regarding the ecotoxicity of the MoS₂, the number of studies is still limited, and more work is needed to effectively evaluate the risks of using this nanomaterial in water treatment.

Core-shell nanocomposite of flower-like molybdenum disulfide nanospheres and molecularly imprinted polymers for electrochemical detection of anti COVID-19 drug favipiravir in biological samples

A novel electrochemical sensor is reported for the detection of the antiviral drug favipiravir based on the core–shell nanocomposite of flower-like molybdenum disulfide (MoS₂) nanospheres and molecularly imprinted polymers (MIPs). The MoS₂@MIP core–shell nanocomposite was prepared via the electrodeposition of a MIP layer on the MoS₂ modified electrode, using o-phenylenediamine as the monomer and favipiravir as the template. The selective binding of target favipiravir at the MoS₂@MIP core–shell nanocomposite produced a redox signal in a concentration dependent manner, which was used for the quantitative analysis. The preparation process of the MoS₂@MIP core–shell nanocomposite was optimized. Under the optimal conditions, the sensor exhibited a wide linear response range of 0.01 ~ 100 nM (1.57*10⁻⁶ ~ 1.57*10⁻² μg mL⁻¹) and a low detection limit of 0.002 nM (3.14*10⁻⁷ μg mL⁻¹). Application of the sensor was demonstrated by detecting favipiravir in a minimum amount of 10 μL biological samples (urine and plasma). Satisfied results in the recovery tests indicated a high potential of favipiravir monitoring in infectious COVID-19 samples.

Measurement of trace bisphenol A in drinking water with combination of immunochromatographic detection technology and SERS method

Sensitive and selective detection of target analyte is very important in many fields such as commodity inspection and quality monitoring. In this work, based on the principle of competitive immunoassay, surface-enhanced Raman spectroscopy (SERS) was used to establish a rapid and highly sensitive method for the detection of trace amounts of bisphenol A in water. Here, Raman molecule 5,5-dithiobis-2-nitrobenzoic acid and anti-BPA antibody were conjugated with Au (core)@Ag (shell) nanoparticle to serve as SERS nanoprobe. After the SERS nanoprobe is combined with the substance to be tested, it uses the siphon effect to pass through the test line and the charging line on the test strip. And the Raman test was performed on the T line with a Raman spectrometer. The detection limitation was 0.1 pg/mL. Compared with the reported gas chromatography, liquid chromatography, fluorescence analysis, and other detection methods, SERS ICA does not demand complicated sample preparation procedures, and has the advantages of simple detection methods, quick results, High sensitivity, good specificity, and low technical demands for laboratory environment and testers. In addition, Raman spectrometers have gradually developed to be portable, making it easier to meet the needs of on-site rapid and highly sensitive detection, and will show broad prospects for applications in the fields of biomedical diagnosis and food safety monitoring.

Nano-Enable Materials Promoting Sustainability and Resilience in Modern Agriculture

Intensive conventional agriculture and climate change have induced severe ecological damages and threatened global food security, claiming a reorientation of agricultural management and public policies towards a more sustainable development model. In this context, nanomaterials promise to support this transition by promoting mitigation, enhancing productivity, and reducing contamination. This review gathers recent research innovations on smart nanoformulations and delivery systems improving crop protection and plant nutrition, nanoremediation strategies for contaminated soils, nanosensors for plant health and food quality and safety monitoring, and nanomaterials as smart food-packaging. It also highlights the impact of engineered nanomaterials on soil microbial communities, and potential environmental risks, along with future research directions. Although large-scale production and in-field testing of nano-agrochemicals are still ongoing, the collected information indicates improvements in uptake, use efficiency, targeted delivery of the active ingredients, and reduction of leaching and pollution. Nanoremediation seems to have a low negative impact on microbial communities while promoting biodiversity. Nanosensors enable high-resolution crop monitoring and sustainable management of the resources, while nano-packaging confers catalytic, antimicrobial, and barrier properties, preserving food safety and preventing food waste. Though, the application of nanomaterials to the agri-food sector requires a specific risk assessment supporting proper regulations and public acceptance.

Integrated contact lens sensor system based on multifunctional ultrathin MoS2 transistors

Smart contact lenses attract extensive interests due to their capability of directly monitoring physiological and ambient information. However, previous demonstrations usually lacked efficient sensor modalities, facile fabrication process, mechanical stability, or biocompatibility. Here, we demonstrate a flexible approach for fabrication of multifunctional smart contact lenses with an ultrathin MoS₂ transistors-based serpentine mesh sensor system. The integrated sensor systems contain a photodetector for receiving optical information, a glucose sensor for monitoring glucose level directly from tear fluid, and a temperature sensor for diagnosing potential corneal disease. Unlike traditional sensors and circuit chips sandwiched in the lens substrate, this serpentine mesh sensor system can be directly mounted onto the lenses and maintain direct contact with tears, delivering high detection sensitivity, while being mechanically robust and not interfering with either blinking or vision. Furthermore, the in vitro cytotoxicity tests reveal good biocompatibility, thus holding promise as next-generation soft electronics for healthcare and medical applications.