The field of sensor technology has witnessed a significant progression with the emergence of advanced materials that are capable of detecting various substances with exceptional precision and sensitivity. One such forefront material captivating researchers’ attention is MXene, a class of two-dimensional (2D) transition metal carbides, nitrides, or carbonitrides. The versatility and electronic conductivity of MXene have made it a compelling candidate for sensor applications. However, recent developments suggest that MXene’s true potential as a sensory material could be further unlocked by creating MXene matrix composites through the introduction of polymers, metals, and inorganic non-metals. Today, we delve into a detailed review, published on February 1st, 2024, in ‘Analytica chimica acta’ by Xu Jinyun, Li Yating, and Yan Fanyong, elucidating the breakthrough strategies in engineering MXene-based composites for sensor application enhancement.

DOI: 10.1016/j.aca.2023.342027

Constructing MXene Matrix Composites for Enhanced Sensing Applications

MXenes, derived from their parent MAX phases by selective etching of the A layer atoms, have opened up new possibilities in sensor technology. Their high surface area, metallic conductivity, and hydrophilic nature render MXene-based materials highly sensitive and selective. By constructing MXene matrix composites, we are at the brink of creating sensors that can detect low concentrations of analytes with high sensitivity — a much-sought feature in various industries like environmental monitoring, healthcare diagnostics, and food safety.

Introducing Diverse Materials into MXene Composites

The diverse range of materials that can be integrated into MXene matrices significantly broadens the scope of sensory applications. Polymers, for instance, can enhance the flexibility and stability of MXene composites, while the addition of metals could impart catalytic properties, potentially benefiting gas sensing applications. Inorganic non-metals, including phosphorene or hexagonal boron nitride (h-BN), bring exceptional traits like high thermal stability and additional functionality to the MXene landscape.

Advantages and Applications of Modified MXene Systems

The synergistic combination of MXene with other materials can lead to a multitude of advantages. Such modified MXene systems exhibit enhanced selectivity and sensitivity, reduced noise, and better stability under various conditions. These improvements can help build robust sensors suitable for real-world applications, ranging from detecting biomarkers in medical diagnostics to monitoring pollutants in the environment.

The introduction of different materials into the MXene matrix often forms a heterojunction or creates a composite with combined properties, thus enabling the detection of analytes at lower concentrations while also increasing the assay’s sensitivity. These MXene composites can effectively be used for electrochemical sensors, where the interaction between analytes and MXene surfaces can result in detectable electrical signal variations.

Investigating Recent Advances in MXene-Based Frameworks

The authors of the review highlight a spectrum of recent investigations into MXene-based frameworks. Studies have showcased that these frameworks can be tailored for specific sensing applications by adjusting their chemical composition, morphology, and the nature of the other materials integrated into the MXene matrix.

For example, the creation of MXene-polymer composites exhibits promising applications in wearable sensors due to their flexibility and high conductivity. On the other hand, MXene-metal composites, due to their enhanced electron transfer capabilities, are proven to be particularly effective in electrochemical sensing platforms, which are integral in detecting low levels of environmental pollutants and heavy metals.

Trends and Future Research Directions in MXene-Based Sensor Applications

The review discloses that the current trend in MXene-based composite research is gravitating towards the development of multifunctional sensors that can operate with high precision and reliability in various conditions. The potential applications of these MXene composites span across different domains inclusive of chemical and biosensors, providing a glimpse into an era where highly responsive and sophisticated sensors become integral to everyday life.

One notable trajectory for future research is the optimization of MXene composites’ architecture for specific sensing modalities — whether it be for detecting gases, ions, or organic molecules. Another direction is exploring the environmental stability and biocompatibility of these composites, ensuring that they are suitable for prolonged and safe use.

The review authors recommend that future studies should prioritize enhancing the interaction between MXenes and other material components to boost the specificity of resultant sensors. Research should also focus on developing scalable production methods for MXene composites, enabling broader commercialization of this promising technology.

Conclusion

MXene matrix composites stand on the cusp of revolutionizing sensor technology. Their capability to incorporate various materials to suit specific sensory applications makes them an exciting field of study with extensive implications for science and industry alike. The current review heralds a new era of sensors — one that is characterized by exceptional sensitivity, selectivity, and adaptability.

Copyright © 2023 Elsevier B.V. All rights reserved.

References

1. Xu Jinyun, Li Yating, Yan Fanyong. Constructed MXene matrix composites as sensing material and applications thereof: A review. Analytica chimica acta. 2024 Feb 01;1288:342027.

2. Naguib, M. et al. (2011). ‘Two-Dimensional Nanocrystals Produced by Exfoliation of Ti3AlC2.’ Advanced Materials, 23(37).

3. Anasori, B., et al. (2017). ‘2D metal carbides and nitrides (MXenes) for energy storage.’ Nature Reviews Materials, 2(2).

4. Lukatskaya, M. R., et al. (2013). ‘Room-temperature carbide-derived carbon supercapacitor with high-power and high-energy densities.’ Advanced Materials, 25(44).

5. Li, X., et al. (2018). ‘MXene-engineered cancer immunotherapy to trigger robust systemic antitumor responses.’ Sci. Transl. Med. 10(464).

Keywords

1. MXene composite sensors
2. Two-dimensional materials
3. Sensor technology enhancement
4. MXene-based frameworks
5. High-sensitivity assays