TY - CONF A1 - Hernandez Garcia, Maria Amparo T1 - Low-cost production of free-form optical components via standard LCD 3D printing for advanced opto-sensing N2 - Nowadays, the use of complex optical elements is increasing also in applications such as miniaturized (bio)chemical opto-sensors. However, this can easily result in considerably high costs, time-consuming fabrication processes and the restricted availability of unconventional optics, which is especially problematic during the development phase of such devices. In this work, we propose LCD 3D printing as an alternative cost-effective technique, which is not only user-friendly but also free of design constrains enabling to fabricate free-form optics. A physical and spectroscopic characterization of six commercially available resins was performed together with the replication of optics and chemical sensing applications as a proof of concept. The optical transparency of the commercial mixtures was evaluated to discriminate the materials optically not suitable for the fabrication of transparent optical elements. Among the six resins, five were considered optimally transparent, with an optical transmittance >85% in the visible spectra range. However, fluorescence analysis of two of these commercial resins, assessed with an excitation-emission matrix (EEM), showed a high autofluorescence in the most common spectral working area of 410–600 nm. Therefore, only three commercial resins were considered for an in-depth evaluation. Ensuring that the refractive index (RI) of the resins complies with that of the most common optical materials, i.e., possesses a RI ~1.5 like polymers such as plexiglass or polycarbonate and glasses such as N-BK7, another important feature is an adequate surface quality of the printed objects. This could be accomplished with a dedicated post-treatment procedure allowing to reach a surface roughness of Rq = 0.07 μm, which agrees well with the values of common glass (Rq = 0.05 μm) and polymer lenses (Rq = 0.075 μm). To demonstrate the suitability of the 3D printed lenses, two different chemical sensors earlier published by us were replicated using the equivalent 3D printed lenses, i.e., a strip test for hydrocarbon detection using a 3D printed aspheric condenser and a microfluidic device for the determination of water chlorination using two cylindrical 3D printed lenses.[1, 2] Independent of the optical material used for the lenses, both assays exhibit similar calibration curves and results (see Figure 1 for one example), suggesting that LCD 3D printing is a suitable technique for the fabrication of free-form optics that allows to design, fabricate and test unconventional optics for miniaturized sensors in a much faster and distinctly less expensive manner. T2 - How to develop a sensor? Academic Approaches vs. Industrial Interests (EU Training School) CY - Kaiserslautern, Germany DA - 18.09.2024 KW - 3D-printing KW - Optics KW - Photopolymerization KW - Rapid prototyping KW - Sensors PY - 2024 AN - OPUS4-61444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hernández García, María Amparo T1 - SAF-based optical biosensor with 3D-printed free-form optics for targeted explosives immuno-detection N2 - Guaranteeing safety and security of citizens requires a significant effort and innovative tools from national and international agencies and governments, especially when it comes to the field of explosives detection. The need to detect Improvised Explosive Devices (IEDs) and Home-made Explosives (HMEs) at a point of suspicion, has grown rapidly due to the ease with which the precursors can be obtained and the reagents synthesised. The limited availability of immunoanalytical tools for HME detection presents an opportunity for the development of new devices, which enable a rapid detection and recognise the target analyte with high specificity and sensitivity. In this work, we introduce an optical biosensor for highly specific and sensitive HME detection. The immunoassay system is placed in a hydrogel environment 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), an advanced microscopy technique. To accomplish this, we made use of recent, commercial high resolution (< 22 µm) Liquid Crystal Display 3D printers to fabricate a parabolic optical element with high refractive index (RI>1.5) and transmission values (>90%) from photo-resin. 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 principally well suitable for the measurements of target analytes at trace levels. T2 - 8th International conference in Biosensing Technology CY - Seville, Spain DA - 12.05.2024 KW - 3D printing KW - Biosensor KW - Fluorescence KW - Explosives PY - 2024 AN - OPUS4-60561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -