Open Access

Ziel des Projekts war die Entwicklung eines miniaturisierten, siliziumbasierten photonischen Biosensors zur schnellen, empfindlichen und kostengünstigen Detektion klinisch relevanter Herzmarker direkt am Patienten (Point-of-Care). Im Fokus standen zwei Biomarker: das kardiale Troponin I (cTnI) als hochspezifischer Akutmarker des Herzinfarkts sowie das C-reaktive Protein (CRP) als prognostischer Entzündungs- und Risikomarker für Herz-Kreislauf-Erkrankungen. Eine schnelle, quantitative und ortsnahe Messung dieser Marker kann die Diagnose beschleunigen und Behandlungsentscheidungen verbessern. Im Projektverlauf wurden die wesentlichen Bausteine einer solchen Plattform erarbeitet und erstmals zusammengeführt: Die Etablierung von Referenzassays (ELISA) als Vergleichsmaßstab, die Entwicklung der Oberflächenchemie für die Sensorchips, ein kontaktloses Druckverfahren zur präzisen Beschichtung der winzigen Sensorstrukturen sowie erste funktionale Messungen am photonischen Biosensor. Als zentrale Ergebnisse konnten die spezifische Detektion eines Proteins in Echtzeit, die gleichzeitige Mehrkanal-Messung über mehrere Sensoren sowie ein erster Nachweis des Biomarkers CRP am Chip demonstriert werden. Der Transfer auf den anspruchsvolleren Marker Troponin I sowie die Bestimmung belastbarer Nachweisgrenzen bleiben offene, gezielt zu bearbeitende Punkte.

Rapid detection and localization of liquid fuel spills is critical for first responders assessing fire and health hazards, yet current methods require ground-based sampling or specialized instrumentation, limiting their practicality for wide-area emergency response. We present a drone-based passive colorimetric sensor system using test strips impregnated with Nile red, similar to colored confetti. Nile red is a solvatochromic dye that undergoes distinct visible color transitions upon exposure to different liquids. The dye is embedded within a polymer matrix that minimizes leaching while providing high optical contrast between dry, water-exposed, and fuel-exposed states. The sensor strips exhibit solvent-specific colorimetric responses within one minute of exposure, readily detectable by standard RGB cameras mounted on unmanned aerial vehicles (UAV) at altitudes up to 50 m. Automated classification was validated at 20 m altitude, enabling remote surveillance of contaminated surfaces without specialized equipment. Color-corrected image analysis using Calibrite ColorChecker calibration ensures reliable interpretation under variable field illumination (625–77,000 lux). Systematic laboratory evaluation of twelve fossil and bio-derived fuels revealed characteristic hue shifts that clearly discriminate ethanol-containing gasoline blends from diesel-range fuels. Field validation confirmed localization and classification of fuel-exposed sensors, achieving F1 scores of 0.94 for gasoline and 0.98 for diesel detection with no false positives in the tested scenarios. This cost-effective and scalable approach provides actionable information on both contamination location and fuel type, crucial for rapid hazard assessment in emergency response scenarios.

Reusable enzyme carriers are valuable for proteomic workflows, yet many supports are expensive or lack robustness. This study describes the covalent immobilization of recombinant trypsin on micrometer-sized corundum particles and assesses their performance in protein digestion and antibody analysis. The corundum surface was cleaned with potassium hydroxide, silanized with 3-aminopropyltriethoxysilane and activated with glutaraldehyde. Recombinant trypsin was then attached, and the resulting imines were reduced with sodium cyanoborohydride. Aromatic amino acid analysis (AAAA) estimated an enzyme loading of approximately 1 µg/mg. Non-specific adsorption of human plasma proteins was suppressed by blocking residual aldehydes with a Tris-glycine-lysine buffer. Compared with free trypsin, immobilization shifted the temperature optimum from 50 to 60 °C and greatly improved stability in 1 M guanidinium hydrochloride. Activity remained above 80% across several reuse cycles, and storage at 4 °C preserved functionality for weeks. When applied to digesting the NISTmAb, immobilized trypsin provided peptide yields and sequence coverage comparable to soluble enzyme and outperformed it at elevated temperatures. MALDI-TOF MS analysis of Herceptin digests yielded fingerprint spectra that correctly identified the antibody and achieved 60% sequence coverage. The combination of low cost, robustness and analytical performance makes corundum-immobilized trypsin an attractive option for research and routine proteomic workflows.

Lateral flow immunoassays (LFA) are widely used for decentralized testing, but their application for in-field plant virus diagnostics is often limited by tedious sample preparation. Here, we present a simplified dipstick LFA for the detection and monitoring of cowpea chlorotic mottle virus (CCMV) as a model plant pathogen. The assay employes a monoclonal mouse antibody for capture and a polyclonal rabbit antibody conjugated to 80-nm gold nanoparticles for detection. Conventional sample and conjugate pads are omitted, allowing the test strips to be dipped directly into wells containing plant extract and antibody-gold conjugate. In addition, no plastic casing was necessary, which significantly reduces waste. It was shown that CCMV concentrations as low as 4 μg/L or 400 pg per sample could be reliably detected in 15 minutes. Specificity tests confirmed that other plant viruses, cowpea mosaic virus (CPMV) and tobacco mosaic virus (TMV), did not produce false positive results. Furthermore, we describe a field-compatible sampling procedure using a manual punch and a disposable syringe. This step combines sample grinding, extraction, and conjugate reconstitution within the syringe frit, enabling the analysis of punched leaf discs without laboratory equipment. When applied to CCMV-infected cowpea plants, the assay revealed systemic infection before visual symptoms became apparent. This work demonstrates that simplified LFAs combined with innovative sampling techniques can provide sensitive, specific, and rapid diagnostics for crop monitoring and support early intervention strategies in agriculture.

This work presents the development of a real-time, multichannel detector for biomolecules based on photonic integrated circuits with super-compact CMOS chips. The presentation focuses on using micro-ring-resonators for bioassays, enabling highly integrated and scalable biosensing-solutions. The talk also covers major challenges like including microfluidic integration, data analysis, custom surface functionalization, and chip packaging.