Recent Trends in Chemsensor Evaluation: Techniques, Challenges, and Future Perspectives

Abstract

Chemsensors have been playing a crucial role in various aspects of biomedical science, analytical and environmental chemistry. The toxic metal ions like Zn, Cd, Cu, Pb and Hg have increased gradually but now have reached an alarming situation, crossing the threshold value. Due to high toxicity of these heavy metals there is an obvious need for a sensor system to detect their presence. Chemsensors prove very promising as the system is rapid, selective, sensible, low-cost, easy-to-use, and has the ability to provide real-time signals. An evaluation of various chemsensors known to us, proves their potential to serve human kind and therefore a deep and wide angle is required to cover these sensors.Apart from fluorescent, luminescent, optical,conjugate, gas, amide based chemsensors have also been developed. During recent times considerable efforts has been has been devoted to the synthesis of chemical compounds having the capability to sense or trap a particular toxic metal ion. A particular category of such compound being sterically encumbered selenium containing species. Due to large covalent radius and greater polarizability of selenium compared to Oxygen, Nitrogen & Sulfur which greatly influences the complexation properties of these compounds. Selenium containing hosts have been reported to display strong affinities with Hg2+ or Ag2+(environmentally toxic metal ions). As confirmed by physicochemical data the presence of multiple soft selenium donor, the flexibility of the arms, steric bulk and open exterior geometry make these molecules potent tool for trapping Hg (II) selectively. Hence such tailored ligand and complexes could serve a great potential for trapping environmentally toxic metal ion and thus has application as sensors. The integration of sustainable materials and self-powered sensing mechanisms further enhances the applicability of chemosensors in real-world scenarios. This paper provides a comprehensive overview of current evaluation techniques, identifies major challenges, and discusses future directions for developing more reliable and efficient chemosensors.

Introduction

Chemical sensors are devices that convert chemical information, such as the concentration of specific analytes, into measurable signals. These sensors range from macroscopic tools like pH electrodes to microscopic molecular receptors that selectively bind target chemicals. Among emerging sensor materials, organoselenium compounds show promise for selectively detecting toxic heavy metals like mercury (Hg²?), due to their soft selenium donor sites and steric properties.

Heavy metal ions such as lead, cadmium, and mercury pose significant health and environmental risks. Traditional detection methods are costly, time-consuming, and impractical for field use, especially in developing countries. Fluorescent probes, including organoselenium-based ones, have been developed for sensitive and selective detection of Hg²?, although challenges remain in biological applications.

Various types of chemosensors have been developed:

• Fluorescent chemosensors for alkali, alkaline earth, and transition metal ions, often based on coordination chemistry or specific metal-induced reactions.

• Anion sensors targeting biologically and environmentally important anions.

• Biomacromolecule sensors for studying DNA, proteins, and other biological molecules.

• Luminescent and optical sensors employing changes in photophysical properties or nanostructured materials.

• Conjugate sensors using photoinduced electron transfer mechanisms.

• Amide-based sensors for detecting heavy metals with applications in forensic and environmental chemistry.

• Gas sensors, including advanced heterostructure designs with metal oxides and 2D materials, offer improved sensitivity and selectivity for detecting pollutants.

Applications of chemosensors span bio-medical diagnostics, environmental monitoring, food safety, and wearable health devices. Despite advances, challenges such as selectivity, stability, biocompatibility, calibration, and real-world robustness limit widespread deployment.

Future directions include integrating photonic crystals, quantum plasmonic technologies, and artificial intelligence to enhance sensitivity and selectivity. Wearable, self-powered sensors that monitor health non-invasively are gaining traction. The ongoing focus is on making chemosensors more cost-effective, user-friendly, and environmentally sustainable, enabling their use in smart cities, personalized medicine, and advanced analytical systems.

Conclusion

The field of chemsensors has developed significantly over 150 years. They have covered a diverse area of human interference, be it clinical biochemistry, medical diagnosis, industrial process control, environmental monitoring, tracing selective toxic metal ion etc. Chemosensors have made significant strides in recent years, driven by advancements in nanomaterials, signal transduction mechanisms, and integration with emerging technologies such as artificial intelligence (AI) and the Internet of Things (IoT). These sensors play a crucial role in environmental monitoring, healthcare diagnostics, food safety, and industrial applications due to their high sensitivity, selectivity, and rapid response times.Despite these advancements, several challenges remain, including sensor stability, cross-sensitivity, miniaturization, and real-world deployment under varying environmental conditions. Researchers are addressing these issues by developing hybrid materials, flexible and wearable sensor platforms, and AI-driven data analysis methods. The present paper highlights few of the important chemsensors used in the area of heavy metal ion detection and their advantages in terms of its easy production, low cost, ease of operation, reliability and good sensor to sensor reproducibility etc. However, operating a sensor in a natural environment poses substantial challenges in terms of ruggedness, long-term stability and calibration. Today, we are witnessing the explosive development in this field of sensors, their applications have covered almost all of the fields. Thebiological and environmental analysis has increasingly stringent requirements imposed by regulatory bodies, so while a current chemsensor may work it may fall short of the required selectivity or sensitivity required for use in a specific practical application in future or so. To meet the upcoming challenges of present and future world we need, and will continue to need an increasing number of chemsensors.

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Copyright © 2025 Dr. Richa Saxena. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.