TY - JOUR A1 - Hülagü, Deniz A1 - Tobias, Charlie A1 - Gojani, Ardian B. A1 - Rurack, Knut A1 - Hodoroaba, Vasile-Dan T1 - From 2D and Single Particle to 3D and Batch Analysis as a Routine Quality Check Procedure for the Morphological Characterization of Core-Shell Microparticles N2 - CS particles show unique properties by merging individual characteristics of the core and the shell materials. An alteration particularly in their surface roughness affects the final performance of the particles in the targeted application. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task employing microscopic techniques being scarce and showing large differences in terms of methodology and results. In our previous work, we have reported a systematic study with a reliable analysis tool, which evaluates profile roughness quantitatively, for individual core-shell microparticles using electron microscopy (EM) images of both types, Scanning Electron Microscopy (SEM) and transmission mode SEM (or TSEM). The SEM images contain two-dimensional (2D) information, therefore, provide profile roughness data only from the projection in the horizontal plane (in other words, from the “belly”) of a spherical particle. The present study offers a practical procedure to give access to more information by tilting the sample holder and hence allowing images of a single particle to be recorded at different orientations under the same view angle. From the analysis of these images, extended information on surface roughness of the particle can be extracted. Thus, instead of obtaining 2D information from a single SEM image, three-dimensional (3D) information is obtained from 2D projections recorded at different particle orientations. T2 - Microscopy and Microanalysis 2022 CY - Oregon, Portland, USA DA - 31.07.2022 KW - Core-shell particles KW - Image processing KW - Roughness KW - Scanning electron microscopy KW - Tilting PY - 2022 DO - https://doi.org/10.1017/S1431927622002094 SN - 1431-9276 VL - 28 IS - S1 SP - 332 EP - 334 PB - Cambridge University Press AN - OPUS4-55373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Climent Terol, Estela A1 - Weller, Michael G. A1 - Martínez-Mánez, R. A1 - Rurack, Knut T1 - Immunochemical design of antibody-gated indicator delivery (gAID) systems based on mesoporous silica nanoparticles N2 - In this work, the optimization of the immunochemical response of antibody-gated indicator delivery (gAID) systems prepared with mesoporous silica nanoparticles has been studied along various lines of system tailoring, targeting the peroxide-type explosive TATP as an exemplary analyte. The mechanism of detection of these gAID systems relies on a displacement of an antibody “cap” bound to hapten derivatives anchored to the surface of a porous hybrid material, allowing the indicator cargo stored in the mesopores to escape and massively amplify the analyte-related signal. Since our aim was to obtain gAID systems with the best possible response in terms of sensitivity, selectivity, and assay time, sera obtained from different immunization boosts were screened, the influence of auxiliary reagents was assessed, structural hapten modification (hapten heterology) was investigated, and various indicator dyes and host materials were tested. Considering that highly selective and sensitive immunological responses are best obtained with high-affinity antibodies which, however, could possess rather slow dissociation constants, leading to slow responses, the main challenge was to optimize the immunochemical recognition system for a rapid response while maintaining a high sensitivity and selectivity. The best performance was observed by grafting a slightly mismatching (heterologous) hapten to the surface of the nanoparticles in combination with high-affinity antibodies as “caps”, yielding for the first time gAID nanomaterials for which the response time could be improved from hours to <5 min. The materials showed favorable detection limits in the lower ppb range and discriminated TATP well against H2O2 and other explosives. Further optimization led to straightforward integration of the materials into a lateral flow assay without further treatment or conditioning of the test strips while still guaranteeing remarkably fast overall assay times. KW - Antibody-gated indicator delivery systems KW - Signal amplification KW - Immunochemical response optimization KW - Test strip analysis KW - TATP KW - Explosives detection KW - Heterologous hapten PY - 2022 DO - https://doi.org/10.1021/acsanm.1c03417 SN - 2574-0970 VL - 5 IS - 1 SP - 626 EP - 641 PB - American Chemical Society CY - Washington, DC AN - OPUS4-54176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -