Surface Chemistry-Engineered Hydrogel-Based Ionic Transistor for Ultra-Sensitive and Rapid Detection of Pharmaceutical Contaminants in Water

Improper disposal and handling of chemotherapeutic drugs allow them to infiltrate water bodies, accelerating the development of drug-resistant bacteria, a significant human health threat. This issue is particularly critical for potent, specialized chemotherapy drugs like Methotrexate and Tamoxifen. These pharmaceutical contaminants not only disrupt ecosystems but also contribute to the spread of drug-resistant strains. To address this, we present an innovative ionic transistor that utilizes a two-dimensional confined channel and a polyvinyl alcohol (PVA)-based hydrogel as the ionic membrane. The surface chemistry of the hydrogel is modified to selectively capture Methotrexate and Tamoxifen, enabling precise detection in various water matrices, including municipal wastewater and natural water bodies. We explored both dual-gated and back-gated transistor configurations, and our device reliably detected these chemotherapy drugs at trace concentrations. Our device demonstrates reliable performance in distinguishing between Methotrexate and Tamoxifen, even at trace concentrations commonly found in contaminated water sources. The integration of the unique electronic properties of the confined channel with the high ionic conductivity of the hydrogel ensures robust and sensitive detection of these pharmaceutical pollutants. This study not only highlights a novel approach to monitoring chemotherapeutic pollutants but also holds great potential for broader environmental applications and future advancements in water quality management.