TY - JOUR A1 - Steglich, P. A1 - Rabus, D. G. A1 - Sada, C. A1 - Paul, Martin A1 - Weller, Michael G. A1 - Mai, C. A1 - Mai, A. T1 - Silicon Photonic Micro-Ring Resonators for Chemical and Biological Sensing: A Tutorial N2 - Silicon photonic micro-ring resonators (MRR) developed on the silicon-on-insulator (SOI) platform, owing to their high sensitivity and small footprint, show great potential for many chemical and biological sensing applications such as label-free detection in environmental monitoring, biomedical engineering, and food analysis. In this tutorial,we provide the theoretical background and give design guidelines for SOI-based MRR as well as examples of surface functionalization procedures for label-free detection of molecules. After introducing the advantages and perspectives of MRR, fundamentals of MRR are described in detail, followed by an introduction to the fabrication methods, which are based on a complementary metal-oxide semiconductor (CMOS) technology. Optimization of MRR for chemical and biological sensing is provided, with special emphasis on the optimization of waveguide geometry. At this point, the difference between chemical bulk sensing and label-free surface sensing is explained, and definitions like waveguide sensitivity, ring sensitivity, overall sensitivity as well as the limit of detection (LoD) of MRR are introduced. Further, we show and explain chemical bulk sensing of sodium chloride (NaCl) in water and provide a recipe for label-free surface sensing. KW - Biosensors KW - Biophotonics KW - Chemosensor KW - Biosensor KW - Microresonator KW - Nanophotonics KW - Optical sensors KW - Photonic sensors KW - Optoelectronic KW - Ring resonator KW - Silicon photonics KW - Miniaturization KW - Lab-on-a-chip KW - Lab-on-chip KW - Waveguide KW - Surface chemistry KW - Silanization KW - Glutaraldehyde KW - Affinity immobilization KW - Antibody KW - Oriented immobilization KW - Real-time measurement PY - 2022 U6 - https://doi.org/10.1109/JSEN.2021.3119547 SN - 1530-437X VL - 22 IS - 11 SP - 10089 EP - 10105 PB - IEEE AN - OPUS4-55147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Paul, Martin T1 - Microarrays for the screening of monoclonal antibodies from supernatants N2 - In this thesis a protocol based on a direct competitive and non-competitive immunoassay using the microarray format was developed to screen emulated hybridoma supernatants against the drug carbamazepine (CBZ). As support, epoxy slides were manufactured by coating microscope glass slides with epoxy silanes. The manufactured epoxy slides showed similar capacity for protein immobilization as commercially available NEXTERION slides, but showed a higher autofluorescence background. On the epoxy slides, protein A, Cys-A, G and Cys-G were immobilized as antibody capturing coating. It could be shown that the Cys-tag considerably increased the immobilization of all compared proteins, especially of protein G. Protein Cys-G immobilized at pH 8-9 was considered the most suitable protein for antibody immobilization due to good spot uniformity and a high binding capacity for IgG. Additionally, in immobilization experiments it could be shown, that 10-500 fold excess of bovine IgG, introduced by two different fetal bovine serum (FBS) products, showed no significant competition on the immobilization of mice or goat IgG on protein Cys-G. To examine the captured antibodies for affinity to CBZ, the CBZ-TOTA-DY654 tracer was custom synthesized. It could be demonstrated, that the tracer antibody interaction was competitive with the tracer precursor, CBZ-TOTA-NH2 and CBZ. Furthermore, the synthesized tracer was also successfully used by externals to evaluate CBZ affine hybriodoma cells in flow cytometry. In the simulated screening, five antibodies with known affinity to CBZ were diluted in a cell culture medium. The screening method allowed to differentiate between affine antibodies (IC50 < 20 µg/ml) and unaffine antibodies (IC50 > 20 µg/ml), when concentrations of 0.1 µg/ml IgG or greater have been used. Of five applied antibodies, all highly affine clones (CE2 and B3212M) were reported as positives while no false-positive samples were observed. The screening included competitive, with around 89500 fold excess of CBZ, and non-competitive tracer incubation on different segments of the same chip, which resulted in total signal suppression on the competitive segment. The screening was performed in 20 hours, only a few nanoliters, of each simulated supernatant, were consumed in the screening process, furthermore in the method standard 96 well MTPs were used and no cleanroom facilities were required. KW - Carbamazepine KW - Microscopic slides KW - Protein A cys KW - Competition KW - Epoxy silanes KW - Supernatant KW - Antibody immobilization PY - 2017 SP - 1 EP - 96 PB - Humboldt-Universität zu Berlin CY - Berlin AN - OPUS4-54645 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wilke, Marco A1 - Röder, Bettina A1 - Paul, Martin A1 - Weller, Michael G. T1 - Sintered Glass Monoliths as New Supports for Affinity Columns N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 minute. Due to the glass material's excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nanofiltration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run. KW - Affinity Chromatography KW - Glass KW - Purification KW - Antibodies KW - Solid support KW - HPLC KW - FPLC KW - Separation PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-529117 SP - 1 PB - MDPI CY - Basel AN - OPUS4-52911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steglich, Patrick A1 - Paul, Martin A1 - Mai, C. A1 - Böhme, A. A1 - Bondarenko, S. A1 - Weller, Michael G. A1 - Mai, A. T1 - A monolithically integrated microfluidic channel in a silicon-based photonic-integrated-circuit technology for biochemical sensing N2 - In this work, a cost-effective optofluidic system is proposed and preliminary experimental results are presented. A microfluidic channel monolithically integrated into a photonic integrated circuit technology is used in conjunction with a cyclic olefin copolymer (COC) substrate to provide fluidic in- and output ports. We report on initial experimental results as well as on the simple and cost-effective fabrication of this optofluidic system by means of micro-milling. KW - Biosensors KW - Biophotonics KW - Optical sensors KW - Photonic sensors KW - Ring resonators KW - Silicon photonics KW - Lab-on-a-chip KW - Microfluidics KW - Chip KW - Biochip PY - 2021 U6 - https://doi.org/10.1117/12.2588791 VL - 11772 SP - 1 EP - 5 PB - SPIE AN - OPUS4-53559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Paul, Martin A1 - Tannenberg, Robert A1 - Tscheuschner, Georg A1 - Wilke, Marco A1 - Weller, Michael G. T1 - Cocaine Detection by a Laser-induced Immunofluorometric Biosensor N2 - The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue in public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect ultra-small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 23 pM (7 ppt) of cocaine with a response time of 90 seconds and a total assay time below 3 minutes. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement. KW - Drug search KW - Customs KW - Confiscation KW - Border surveillance KW - Narcotics KW - International drug trade KW - Drug trafficking KW - Illicit drug KW - Immunosensor KW - Antibodies KW - Detection PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-529951 SP - 1 PB - MDPI CY - Basel AN - OPUS4-52995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Martin A1 - Tannenberg, Robert A1 - Tscheuschner, Georg A1 - Ponader, Marco A1 - Weller, Michael G. T1 - Cocaine Detection by a Laser-Induced Immunofluorometric Biosensor N2 - The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue for public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 7 ppt (23 pM) of cocaine with a response time of 90 s and a total assay time below 3 min. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement. KW - Online detection KW - Security KW - Monoclonal antibody KW - Microfluidic mixing KW - Microfluidics KW - Lab-on-a-chip KW - Monolithic column KW - Affinity chromatography KW - Laser-induced fluorescence KW - LIF KW - ELISA KW - Wipe test KW - Low-cost PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-534487 VL - 11 IS - 9 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-53448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Steglich, P. A1 - Rabus, D. G. A1 - Sada, C. A1 - Paul, Martin A1 - Weller, Michael G. A1 - Mai, C. A1 - Mai, A. T1 - Silicon Photonic Micro-Ring Resonators for Chemical and Biological Sensing: A Tutorial N2 - Silicon photonic micro-ring resonators (MRR) developed on the silicon-on-insulator (SOI) platform, owing to their high sensitivity and small footprint, show great potential for many chemical and biological sensing applications such as label-free detection in environmental monitoring, biomedical engineering, and food analysis. In this tutorial, we provide the theoretical background and give design guidelines for SOI-based MRR as well as examples of surface functionalization procedures for label-free detection of molecules. After introducing the advantages and perspectives of MRR, fundamentals of MRR are described in detail, followed by an introduction to the fabrication methods, which are based on a complementary metal-oxide semiconductor (CMOS) technology. Optimization of MRR for chemical and biological sensing is provided, with special emphasis on the optimization of waveguide geometry. At this point, the difference between chemical bulk sensing and label-free surface sensing is explained, and definitions like waveguide sensitivity, ring sensitivity, overall sensitivity as well as the limit of detection (LoD) of MRR are introduced. Further, we show and explain chemical bulk sensing of sodium chloride (NaCl) in water and provide a recipe for label-free surface sensing. KW - Lab on a chip KW - Biosensor KW - Cmos KW - Silanization KW - Surface derivatization KW - Evanescent wave PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-529360 SP - 1 EP - 18 PB - IEEE CY - Piscataway Township AN - OPUS4-52936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilke, Marco A1 - Röder, Bettina A1 - Paul, Martin A1 - Weller, Michael G. T1 - Sintered glass monoliths as supports for affinity columns N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 min. Due to the glass material’s excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nano-filtration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run. KW - Affinity Chromatography KW - Affinity Extraction KW - Affinity Separation KW - Protein Purification KW - Down Stream Processing KW - Antibody Purification KW - Diagnostic Antibodies KW - Therapeutic Antibodies KW - Automated Purification KW - HPLC KW - FPLC KW - IgG determination KW - Concentration step KW - Monoclonal Antibodies KW - Polyclonal Antibodies KW - Human Plasma KW - Glass Support KW - Borosilicate Glass KW - Monolith KW - Sintered Material KW - Additive Manufacturing KW - Column holder KW - Construction KW - Open Science KW - Citizen Science KW - Protein A KW - Regeneration KW - High-Speed Separations KW - Robustness PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-527581 SN - 2297-8739 VL - 8 IS - 5 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-52758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paul, Martin A1 - Schleeh, C. A1 - Weller, Michael G. T1 - Development of a high-sensitivity biosensor for the quasi-continuous detection of the explosive TNT and the illegal drug cocaine N2 - An immunofluorometric biosensor with laser-induced fluorescence detection was presented. For TNT an LOD of 60 ppb and for cocaine an LOD of 9 ppb was achieved. A swipe test was performed in less than 3 minutes. No significant cross-reactivity was observed. T2 - 15. Interdisziplinäres Doktorandenseminar des Arbeitskreises Prozessanalytik der GDCh CY - Online meeting DA - 06.09.2021 KW - PETN KW - HMX KW - RDX KW - Microfluidic mixing KW - Lab-on-a-chip KW - Affinity column KW - Monolithic material KW - Sintered glass KW - Dy-654 KW - Flowcell KW - Epifluorescence KW - CMOS camera KW - Diode laser KW - Antibody screening PY - 2021 AN - OPUS4-53329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paul, Martin A1 - Weller, Michael G. T1 - Fast Detection of TNT at ppt Level by an Immunofluorometric Biosensor N2 - The mechanism of this system is based on kinetic competition. This biosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. If the explosive 2,4,6-trinitrotoluene (TNT) is introduced some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein. The fluorescence is detected by highly sensitive laser-induced fluorescence with a conventional CMOS camera. The system achieved limits of detection of approx.1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of TNT. The total assay time is less than 8 minutes. A cross-reactivity test with 5000 pM solutions of pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) showed no cross reactivity. T2 - Doktorandenseminar 2020 des Arbeitskreis-Prozessanalytik CY - Online meeting DA - 21.09.2020 KW - TNT KW - Explosive KW - Antibody KW - Fluorescence KW - Biosensor KW - Affinity PY - 2020 AN - OPUS4-51314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Martin A1 - Tscheuschner, Georg A1 - Herrmann, Stefan A1 - Weller, Michael G. T1 - Fast Detection of 2,4,6-Trinitrotoluene (TNT) at ppt Level by a Laser-Induced Immunofluorometric Biosensor N2 - The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports venues, theaters, and other large buildings. Security in these environments can be achieved by different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of the explosive 2,4,6-trinitrotoluene (TNT), some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of TNT. The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds. The consumption of the labeled antibody is surprisingly low: 1 mg of the reagent would be sufficient for more than one year of continuous biosensor operation. KW - Airport KW - Aviation KW - Bombs KW - Terrorism KW - Biosensing KW - Continuous Sensor KW - High-Speed KW - Ultrasensitive PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-511245 VL - 10 IS - 8 SP - 89 PB - MDPI CY - Basel AN - OPUS4-51124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Paul, Martin A1 - Weller, Michael G. T1 - Antibody Screening by Microarray Technology – Direct Identification of Selective High-Affinity Clones N2 - The primary screening of hybridoma cells is a time-critical and laborious step during the development of monoclonal antibodies. Often critical errors occur in this phase, which supports the notion that the generation of monoclonal antibodies with hybridoma technology is difficult to control and hence a risky venture. We think that it is crucial to improve the screening process to eliminate most of the immanent deficits of the conventional approach. With this new microarray-based procedure, several advances could be achieved: Selectivity for excellent binders, high throughput, reproducible signals, avoidance of misleading avidity (multivalency) effects, and simultaneous performance of competition experiments. The latter can directly be used to select clones of desired cross-reactivity properties. In this paper, a model system with two excellent clones against carbamazepine, two weak clones and blank supernatant has been designed to examine the effectiveness of the new system. The excellent clones could be detected largely independent of the IgG concentration, which is unknown during the clone screening since the determination and subsequent adjustment of the antibody concentration is not possible in most cases. Furthermore, in this approach, the enrichment, isolation, and purification of IgG for characterization is not necessary. Raw cell culture supernatant can be used directly, even when fetal calf serum (FCS) or other complex media had been used. In addition, an improved method for the oriented antibody-immobilization on epoxy-silanized slides is presented. Based on the results of this model system, we conclude that this approach should be preferable to most other protocols leading to many of false positives, causing expensive and lengthy confirmation steps to weed out the poor clones. KW - Hybridoma KW - Monoclonal Antibodies KW - Clones KW - Competitive Immunoassay KW - Hapten Immunoassay KW - False Positives PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-506621 SN - 2310-287X SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-50662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Steglich, P. A1 - Bondarenko, S. A1 - Mai, C. A1 - Paul, Martin A1 - Weller, Michael G. A1 - Mai, A. T1 - CMOS-Compatible Silicon Photonic Sensor for Refractive Index Sensing Using Local Back-Side Release N2 - Silicon photonic sensors are promising candidates for lab-on-a-chip solutions with versatile applications and scalable production prospects using complementary metal-oxide semiconductor (CMOS) fabrication methods. However, the widespread use has been hindered because the sensing area adjoins optical and electrical components making packaging and sensor handling challenging. In this work, a local back-side release of the photonic sensor is employed, enabling a separation of the sensing area from the rest of the chip. This approach allows preserving the compatibility of photonic integrated circuits in the front-end of line and metal interconnects in the back-end of line. The sensor is based on a micro-ring resonator and is fabricated on wafer-level using a CMOS technology. We revealed a ring resonator sensitivity for homogeneous sensing of 106 nm/RIU. KW - Photonic biosensor KW - Lab-on-a-chip KW - Ring resonator KW - Resonance wavelength shift KW - PIC technology KW - Back-side integration PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-517139 VL - 32 IS - 19 SP - 1241 EP - 1244 PB - IEEE AN - OPUS4-51713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paul, Martin A1 - Schleeh, Clemens A1 - Weller, Michael G. T1 - High sensitivity online detection of Trinitrotoluene (TNT) N2 - The antibody A.1.1.1 was labeled and found to be very sensitive and highly selective for TNT. A novel monolithic affinity column was coated with a Trinitroaniline (TNA)-BSA affinity conjugate and a custom laser induced fluorescence detector were built to allow for continuous and sensitive detection. The affinity column combined with the high sensitivity detector resulted in a limit of detection of approx. 100 pM TNT or 20 ppt TNT for offline detection and was able to detect picogram amounts within three minutes. T2 - SALSA Make and Measure 2020 CY - Online meeting DA - 15.10.2020 KW - Biosensor KW - Explosive KW - Antibody KW - Online KW - Fluorescence PY - 2020 AN - OPUS4-51529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Martin A1 - Weller, Michael G. T1 - Antibody Screening by Microarray Technology - Direct Identification of Selective High-Affinity Clones N2 - The primary screening of hybridoma cells is a time-critical and laborious step during the development of monoclonal antibodies. Often, critical errors occur in this phase, which supports the notion that the generation of monoclonal antibodies with hybridoma technology is difficult to control and hence, a risky venture. We think that it is crucial to improve the screening process to eliminate most of the critical deficits of the conventional approach. With this new microarray-based procedure, several advances could be achieved: Selectivity for excellent binders, high-throughput, reproducible signals, avoidance of misleading avidity (multivalency) effects, and performance of simultaneous competition experiments. The latter can also be used to select clones of desired cross-reactivity properties. In this paper, a model system with two excellent clones against carbamazepine, two weak clones, and blank supernatant containing fetal bovine serum was designed to examine the effectiveness of the new system. The excellent clones could be detected largely independent of the immunoglobulin G (IgG) concentration, which is usually unknown during the clone screening since the determination and subsequent adjustment of the antibody concentration are not feasible in most cases. Furthermore, in this approach, the enrichment, isolation, and purification of IgG for characterization is not necessary. Raw cell culture supernatant can be used directly, even when fetal calf serum (FCS) or other complex media is used. In addition, an improved method for the oriented antibody-immobilization on epoxy-silanized slides is presented. Based on the results of this model system with simulated hybridoma supernatants, we conclude that this approach should be preferable to most other protocols leading to many false positives, causing expensive and lengthy elimination steps to weed out the poor clones. KW - ELISA KW - Immunoassay KW - Microarray KW - Lab-on-a-chip KW - Miniaturization KW - Aautomatisation KW - HTS KW - High-throughput KW - Screening KW - Fluorescence KW - Label KW - Hybridoma KW - Inhibition PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-503361 SN - 2073-4468 VL - 9 IS - 1 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-50336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steglich, P. A1 - Mai, C. A1 - Bondarenko, S. A1 - Paul, Martin A1 - Weller, Michael G. A1 - Schrader, S. A1 - Mai, A. T1 - BioPIC - Integration of Biosensors based on Photonic Integrated Circuits by Local-Backside Etching N2 - Silicon photonic sensors are promising candidates for lab-on-a-chip solutions with versatile applications and scalable production prospects using complementary metal-oxide semiconductor (CMOS) fabrication methods. However, the widespread use has been hindered because the sensing area adjoins optical and electrical components making packaging and sensor handling challenging. In this work, a local back-side release of the photonic sensor is employed, enabling a separation of the sensing area from the rest of the chip. This approach allows preserving the compatibility of photonic integrated circuits in the front-end of line and metal interconnects in the back-end of line. T2 - ATTRACT online Conference CY - Online meeting DA - 22.09.2020 KW - Silicon Photonics KW - Photonic Sensor KW - Photonic Integrated Circuits KW - Point-Of-Care-Diagnostics KW - CMOS KW - Microfluidics KW - Lab-on-a-chip KW - Ring resonator PY - 2020 UR - https://attract-eu.com/showroom/project/integration-of-biosensors-based-on-photonic-integrated-circuits-by-local-backside-etching-biopic/ SP - 1 EP - 5 AN - OPUS4-51735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paul, Martin A1 - Weller, Michael G. T1 - Development of a biosensor for the online detection of explosives N2 - An affinity column, which removed up to 99 % of high affinity Anti-TNT antibody at high antibody concentrations, was manufactured based on a monolithic glass core and a trinitroaniline-BSA conjugate. To detect the label Dy654 in the nM range an epi-fluorescence microscope setup with a CMOS camera was established to serve as online fluorescence detector with multiplexing capabilities. T2 - ANAKON 2019 CY - Münster, Germany DA - 25.03.2019 KW - Online fluorescence KW - Trinitro KW - Affinty KW - Antibody PY - 2019 AN - OPUS4-47745 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tannenberg, Robert A1 - Paul, Martin A1 - Röder, Bettina A1 - Gande, S. L. A1 - Sreeramulu, S. A1 - Saxena, K. A1 - Richter, C. A1 - Schwalbe, H. A1 - Swart, C. A1 - Weller, Michael G. T1 - Chemiluminescence biosensor for the determination of cardiac troponin I (cTnI) N2 - Cardiac troponin I (cTnI) is a crucial biomarker for diagnosing cardiac vascular diseases, including acute myocardial infarction (AMI). This study presents a proof-of-concept chemiluminescence-based immunosensor for rapid and accurate measurement of cTnI, with the potential for online monitoring. The immunosensor incorporates a flow cell design and a sensitive complementary metal-oxide-semiconductor (CMOS) camera for optical readout. A microfluidic setup was established to enable selective and quasi-online determination of cTnI within ten minutes. The sensor was tested with recombinant cTnI in phosphate buffer, demonstrating measurements in the concentration range of 2–25 µg/L, with a limit of detection (LoD) of 0.6 µg/L (23 pmol/L) achieved using the optimized system. The immunosensor exhibited high selectivity, as no cross-reactivity was observed with other recombinant proteins such as cTnT and cTnC at a concentration of 16 µg/L. Measurements with diluted blood plasma and serum yielded an LoD of 60 µg/L (2.4 nmol/L) and 70 µg/L (2.9 nmol/L), respectively. This biosensor offers a promising approach for the rapid and sensitive detection of cTnI, contributing to the diagnosis and management of acute myocardial infarction and other cardiac vascular diseases. N2 - Das kardiale Troponin I (cTnI) ist ein wichtiger Biomarker für die Diagnose von Herz-Kreislauf-Erkrankungen, einschließlich des akuten Myokardinfarkts (AMI). In dieser Studie wird ein auf Chemilumineszenz basierender Immunsensor für die schnelle und genaue Messung von cTnI vorgestellt, der das Potenzial für eine Online-Überwachung hat. Der Immunsensor besteht aus einer Durchflusszelle und einer empfindlichen CMOS-Kamera (Complementary Metal-Oxide-Semiconductor) zur optischen Detektion. Es wurde ein mikrofluidischer Aufbau entwickelt, der eine selektive und quasi Online-Bestimmung von cTnI innerhalb von zehn Minuten ermöglicht. Der Sensor wurde mit rekombinantem cTnI in Phosphatpuffer getestet und zeigte einen Messbereich von 2-25 µg/L, wobei mit dem optimierten System eine Nachweisgrenze (LoD) von 0,6 µg/L (23 pmol/L) erreicht wurde. Der Immunsensor zeigte eine hohe Selektivität, da keine Kreuzreaktivität mit anderen rekombinanten Proteinen wie cTnT und cTnC bei einer Konzentration von 16 µg/L beobachtet wurde. Messungen mit verdünntem Blutplasma und Serum ergaben einen LoD von 60 µg/L (2,4 nmol/L) bzw. 70 µg/L (2,9 nmol/L). Dieser Biosensor bietet einen vielversprechenden Ansatz für den schnellen und empfindlichen Nachweis von cTnI, der zur Diagnose und Behandlung des akuten Myokardinfarkts und anderer kardialer Gefäßerkrankungen beitragen kann. KW - Acute myocardial infarction KW - Heart attack KW - Emergency KW - Diagnosis KW - Cardiac troponin KW - Biomarker KW - Immunosensor KW - Biosensor KW - Chemiluminescence KW - Luminol KW - Peroxidase KW - Monoclonal antibodies KW - Flow injection immunoassay KW - Immunometric assay KW - Immunometric biosensor KW - Microfluidic system KW - Monolithic column KW - Online biosensor PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-575471 SN - 2079-6374 VL - 13 IS - 4 SP - 1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-57547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -