TY - CONF A1 - Hernandez Garcia, Maria Amparo T1 - Optical immuno-detection of targeted explosives using 3D printed optical elements N2 - Immuno-detection biosensors represent a prominent and recognized field within the classical analytical tools. Their popularity stems not only from their selectivity but also from their remarkable sensitivity. However, in applications where trace detection is required, especially with small molecules, sensitivity can become a limitation. For example, this is the case in forensic analysis where the in-situ detection of explosives remains a challenge due to the limited availability of sensitive sensor platforms. In this work, we present an optical biosensor for the highly specific and sensitive detection of Home-Made Explosives (HME). The immunoassay system is placed in a hydrogel environment that is permeable to the analyte and transparent to light interrogating the fluorescently labelled antibodies. The readout of the immunoanalytical system is realized with Supercritical Angle Fluorescence (SAF). This advanced microscopy technique, facilitates the fluorescence detection at the surface level discriminating bulk emission.[1, 2] To achieve this, we have used a commercially available high-resolution (< 22 µm) SLA printer to fabricate a SAF element.[3] Prior to fabrication, an optical simulation was performed to validate the accuracy of the system’s light path for optimum SAF collection. This affordable technology, with a short fabrication time and no design constraints, grants us the freedom to fabricate a parabolic optical element out of transparent resin specifically tailored to collect the emission generated at the interface of the immunoanalytical system. In order to obtain an antibody-specific interface, glass surface was functionalised with the hapten related to the target analyte. In this way, a surface with non-covalently attached labelled antibodies is obtained, making possible their displacement, and, hence, SAF modulation (Figure 1). Aiming at a new generation of sensors, which not only can meet the requirements of trace detection, but can also be used for substance identification, the combination of immunoanalytical recognition with SAF detection offers a modularity and versatility that is, in principle, well suited to the measurement of target analytes at trace levels. T2 - Europtrode 2026 CY - Jena, Germany DA - 29.03.2026 KW - 3D printing KW - SAF KW - Free-form optics KW - Immunoassay PY - 2026 AN - OPUS4-65814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -