Advanced Materials for Sensing Applications: An Overview

By Ankit SinghReviewed by Susha Cheriyedath, M.Sc.Sep 11 2024

With technology advancing at a rapid pace, the need for sensors that can detect even the smallest changes in physical, chemical, or biological environments has grown significantly. Advanced materials are at the core of this innovation, offering greater sensitivity, accuracy, and durability. Whether it is in medical diagnostics or keeping tabs on environmental changes, these materials are transforming how we monitor the world around us, delivering solutions that are not only precise but also highly reliable.

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From Silicon to Smart Materials

The history of advanced materials in sensing applications dates back to the mid-20^th century, when the first solid-state sensors were introduced. These early sensors, built with materials like silicon—still a cornerstone of semiconductor technology—had limited sensitivity and selectivity.

By the late 20^th century, advancements in materials science brought about ceramics and polymers, enabling more specialized sensors for humidity, pressure, and temperature measurement. The 1990s saw a significant leap forward with the advent of nanomaterials. Carbon nanotubes (CNTs) and graphene, in particular, transformed sensor capabilities by offering greater surface area and improved conductivity, both essential for heightened sensitivity.

Today, sensing materials have evolved to include a wide range of nanostructures, functionalized surfaces, and intelligent materials, enabling cutting-edge applications in healthcare, environmental monitoring, and industrial automation.

Nanomaterials

Nanomaterials, particularly carbon-based materials like graphene and CNTs, have become indispensable in advanced sensing technologies. Graphene, a single layer of carbon atoms just one atom thick, is celebrated for its high electrical conductivity and large surface area, making it ideal for detecting trace amounts of gases, chemicals, and biomolecules. Recent studies have shown that graphene-based gas sensors can detect gases like nitrogen dioxide at concentrations as low as parts per billion, a crucial feature for monitoring air quality.¹

Similarly, CNTs have shown exceptional potential in chemical and biosensing applications. Their high aspect ratio and unique electrical properties allow them to respond sensitively to even the slightest changes in their environment. For example, researchers have successfully demonstrated CNTs' effectiveness in detecting glucose levels, offering new possibilities for diabetes management. This class of nanomaterials paves the way for miniaturized, high-performance sensors across industries, from healthcare to environmental protection.¹

One such real-world example is a CNT-based biosensor developed for glucose detection in human blood plasma. This CNT-based sensor not only provided more accurate and faster glucose readings compared to current technologies but also demonstrated greater sensitivity, potentially lowering the detection limit for glucose. This advancement could open the door to improved, non-invasive monitoring solutions in diabetes management, enhancing both patient comfort and clinical outcomes.⁸

Two-Dimensional Materials Beyond Graphene

While graphene has long dominated the field of two-dimensional (2D) materials, other 2D materials, such as transition metal dichalcogenides (TMDs) like molybdenum disulfide (MoS₂), are emerging as promising candidates for advanced sensing applications. Unlike graphene, TMDs possess a bandgap, making them ideal for applications requiring semiconducting properties.⁵

MoS₂-based sensors, for instance, have demonstrated high sensitivity to gases such as ammonia and methane, which has significant potential for environmental monitoring and industrial safety. The unique electronic properties and mechanical flexibility of these materials allow for the development of highly sensitive, flexible sensors that can be seamlessly integrated into wearable and portable devices.⁵

Metal-Organic Frameworks

Metal-organic frameworks (MOFs) represent another highly promising class of materials that have garnered significant attention for sensing applications. Composed of metal ions and organic ligands arranged in crystalline structures, MOFs are highly porous, making them ideal for gas sensing. Their remarkable specificity and responsiveness to volatile organic compounds (VOCs) are particularly valuable for environmental monitoring and industrial safety.²

One of the key advantages of MOFs is their tunable nature, allowing researchers to design them for specific sensing targets. For example, MOFs can be engineered to detect harmful gases such as ammonia or hydrogen sulfide. In addition, MOF-based sensors have shown potential in medical diagnostics, where they can detect biomarkers in exhaled breath, offering a non-invasive method to monitor diseases like lung cancer.²

In a recent study published in the Chemical Engineering Journal, researchers were able to successfully demonstrate the use of MOFs for selective gas detection at room temperature. MOFs exhibited high sensitivity to hazardous hydrogen sulfide gas, surpassing conventional materials in both speed and accuracy. The study's findings hold significant promise for industries requiring real-time gas monitoring, such as chemical plants and environmental monitoring systems, where rapid detection is critical for safety.⁷

Conducting Polymers

Conducting polymers such as polyaniline and polypyrrole have emerged as attractive materials for sensing applications due to their unique electrical properties and flexibility. These substances can be readily synthesized and tailored to accommodate specific sensing needs, rendering them highly versatile. Polyaniline-based sensors have demonstrated particular effectiveness in detecting ammonia, a significant gas utilized in diverse industrial operations and healthcare diagnostics.³

The flexibility of conducting polymers also allows for their integration into wearable sensors, a rapidly growing field. For instance, polypyrrole has been used to create flexible, skin-compatible sensors capable of monitoring physiological indicators like body temperature and hydration levels. This positions conducting polymers as key materials in the development of wearable health monitoring devices.⁴

Quantum Dots

Quantum dots (QDs), semiconductor nanoparticles, have garnered increasing attention in optical sensing due to their size-dependent optical properties. These materials excel in fluorescent sensors, as their light emission can be precisely tuned to specific wavelengths.

The tunability of QDs allows for the development of multi-functional sensors capable of detecting various analytes simultaneously. This has broad applications in medical diagnostics, where early and accurate detection is critical. Moreover, QD-based sensors are being explored for environmental applications, such as water quality monitoring, where they can detect contaminants like heavy metals and pesticides.⁶

A recent Chemosensors study highlighted the use of QD-based fluorescent immunosensor for cancer biomarker detection in blood. Functionalized with specific biomolecules, the QDs were able to detect trace amounts of biomarkers, allowing for earlier cancer diagnosis. This advancement marks a notable stride in non-invasive diagnostic technologies, presenting the opportunity for broader adoption in oncology clinical settings. It could pave the way for more prompt interventions and tailored treatments for cancer patients.⁹

Innovators in Action

Several leading companies are at the forefront of commercializing sensors built with advanced materials. For example, Honeywell and Siemens have integrated nanomaterials into their environmental monitoring devices, significantly improving sensitivity and selectivity. Bosch is also advancing the field by developing automotive sensors that use materials like transition metal dichalcogenides (TMDs) and graphene to monitor gases and pollutants.

In the healthcare sector, companies like Abbott and Medtronic are utilizing advanced materials in medical sensors. Abbott’s continuous glucose monitoring system, for instance, employs nanomaterials to provide real-time blood sugar readings, marking a major breakthrough in diabetes management. Similarly, Medtronic's Guardian^™ sensors integrate cutting-edge materials to offer improved accuracy and durability for glucose monitoring. These innovators are harnessing advanced materials to expand the possibilities of sensor technology in various commercial applications.

Challenges in the Field

Despite the significant advancements in the development of advanced materials for sensing applications, several key challenges remain. One of the foremost issues is the scalability of production. While materials such as graphene and QDs exhibit exceptional performance in laboratory settings, scaling up their production for commercial use poses substantial difficulties. This challenge limits their broader adoption, especially in industries where cost-effective mass production is essential.

Another critical challenge is ensuring the long-term stability and durability of sensors that utilize advanced materials. In practical, real-world environments, sensors must maintain consistent performance over extended periods. However, the complex nature of some advanced materials can impact their durability, raising concerns about their reliability in large-scale applications.

Integration into existing electronic systems further complicates the use of these materials. Advanced materials often require specialized fabrication techniques that are both time-intensive and costly. This need for tailored processes creates barriers to compatibility with current manufacturing systems, slowing down widespread adoption. Overcoming these challenges is crucial for unlocking the full potential of advanced materials in commercial sensor technologies.

Future Prospects and Conclusion

Advanced materials are reshaping the landscape of sensing technology, offering breakthroughs in sensitivity, precision, and versatility across multiple industries. From healthcare to environmental monitoring, these materials have unlocked new possibilities that were previously unattainable with conventional technologies. As research continues and challenges like scalability and integration are addressed, the potential for these materials will only grow.

Looking ahead, the combination of advanced materials with emerging technologies like artificial intelligence promises to revolutionize the way sensors operate, enabling real-time analysis and smarter, more efficient solutions. The future of sensing is bright, and advanced materials will be at the heart of the next wave of innovation.

The Sensors Industry: A Comprehensive Guide

References and Further Reading

1. Raya, I. et al. (2022). A review of gas sensors based on carbon nanomaterial. Carbon Lett. 32, 339–364. DOI:10.1007/s42823-021-00276-9. https://link.springer.com/article/10.1007/s42823-021-00276-9
2. Li, H.-Y. et al. (2020). Functional metal–organic frameworks as effective sensors of gases and volatile compounds. Chemical Society Reviews, 49(17), 6364–6401. DOI:10.1039/c9cs00778d. https://pubs.rsc.org/en/content/articlelanding/2021/1v/c9cs00778d/
3. Dipak, P. et al. (2020). Synthesis of polyaniline (printable nanoink) gas sensor for the detection of ammonia gas. J Mater Sci: Mater Electron 31, 22512–22521. DOI:10.1007/s10854-020-04760-2. https://link.springer.com/article/10.1007/s10854-020-04760-2
4. Liu, X. et al. (2024). Organic Flexible Electronics for Innovative Applications in Electronic Skin. Advanced Materials Technologies. DOI:10.1002/admt.202400661. https://onlinelibrary.wiley.com/doi/abs/10.1002/admt.202400661
5. Chettri, B. et al. (2022). First principle insight into co-doped MoS2 for sensing NH3 and CH4. Facta universitatis - series: Electronics and Energetics, 35(1), 43–59. DOI:10.2298/fuee2201043c. https://casopisi.junis.ni.ac.rs/index.php/FUElectEnerg/article/view/8205
6. Cotta, M. A. (2020). Quantum Dots and Their Applications: What Lies Ahead? ACS Applied Nano Materials, 3(6), 4920–4924. DOI:10.1021/acsanm.0c01386. https://pubs.acs.org/doi/full/10.1021/acsanm.0c01386
7. Kou, R. et al. (2024). Engineering defective organic–inorganic heterojunctions as an alternative approach to precious metal modification in ultrasensitive H2S gas detection at room temperature. Chemical Engineering Journal, 154678. DOI:10.1016/j.cej.2024.154678. https://www.sciencedirect.com/science/article/abs/pii/S1385894724061692
8. Azimi, S. et al. (2020). Plasma‐functionalized Highly Aligned CNT‐based Biosensor for Point of Care Determination of Glucose in Human Blood Plasma. Electroanalysis, 32(2), 394–403. DOI:10.1002/elan.201800895. https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/abs/10.1002/elan.201800895
9. Sousa, M. P. et al. (2022). New Quantum-Dot-Based Fluorescent Immunosensor for Cancer Biomarker Detection. Chemosensors, 10(12), 518. DOI:10.3390/chemosensors10120518. https://www.mdpi.com/2227-9040/10/12/518

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