TY - JOUR

T1 - Optimization of the angle for scattered light measurements in 3D-printed cultivation vessels

AU - Debener, Nicolas

AU - Kuhnke, Louis Maximilian

AU - Beutel, Sascha

AU - Bahnemann, Janina

N1 - Publisher Copyright: © The Author(s) 2025.

PY - 2025/10

Y1 - 2025/10

N2 - Monitoring key parameters during the cultivation of microorganisms—including biomass concentration—is often a crucial prerequisite for attaining reproducible results in the field of biotechnology. In order to overcome the drawbacks associated with conventional methods for assessing biomass concentration (such as cell dry weight or optical density measurements), several devices to facilitate continuous online monitoring have been developed. Yet despite the success of innovative solutions (such as acceleration sensors) in addressing the challenging dynamical behavior of liquids within shaken systems, the performance of these sensors can still be affected by reflections at the liquid–air interface or at the top of the cultivation vessels. In our previous work, a 3D-printed cultivation vessel equipped with modified optical waveguide paths was utilized in an effort to overcome this challenge, allowing for the measurement of scattered light in a lateral direction. In this work, we developed an optical adapter that allows for the rapid assessment of the optimal measurement angle of excitation and detection within these 3D-printed cultivation vessels. The findings of the present study indicate that an angle of 110° yields higher signal intensities and enhanced sensitivity in comparison to larger angles, and this finding was additionally confirmed for a set of biotechnologically relevant microorganisms. While these results suggest that the angle of 110° should be integrated into the cultivation vessels in the future, the optical adapter also holds the potential to further investigate vessels with different sizes or geometries.

AB - Monitoring key parameters during the cultivation of microorganisms—including biomass concentration—is often a crucial prerequisite for attaining reproducible results in the field of biotechnology. In order to overcome the drawbacks associated with conventional methods for assessing biomass concentration (such as cell dry weight or optical density measurements), several devices to facilitate continuous online monitoring have been developed. Yet despite the success of innovative solutions (such as acceleration sensors) in addressing the challenging dynamical behavior of liquids within shaken systems, the performance of these sensors can still be affected by reflections at the liquid–air interface or at the top of the cultivation vessels. In our previous work, a 3D-printed cultivation vessel equipped with modified optical waveguide paths was utilized in an effort to overcome this challenge, allowing for the measurement of scattered light in a lateral direction. In this work, we developed an optical adapter that allows for the rapid assessment of the optimal measurement angle of excitation and detection within these 3D-printed cultivation vessels. The findings of the present study indicate that an angle of 110° yields higher signal intensities and enhanced sensitivity in comparison to larger angles, and this finding was additionally confirmed for a set of biotechnologically relevant microorganisms. While these results suggest that the angle of 110° should be integrated into the cultivation vessels in the future, the optical adapter also holds the potential to further investigate vessels with different sizes or geometries.

KW - 3D printing

KW - Light scattering

KW - Online monitoring

KW - Optical waveguide

UR - http://www.scopus.com/inward/record.url?scp=105018345153&partnerID=8YFLogxK

U2 - 10.1007/s00216-025-06131-4

DO - 10.1007/s00216-025-06131-4

M3 - Article

C2 - 41039129

AN - SCOPUS:105018345153

VL - 417

SP - 5627

EP - 5635

JO - Analytical and Bioanalytical Chemistry

JF - Analytical and Bioanalytical Chemistry

SN - 1618-2642

IS - 25

ER -