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Development and validation of a 3D-printed spectral verification system for colorimetric-based biosensors
Jacqueline Balles1,2, Robert Reiners1, Dieter Spiehl1,2, Edgar Dörsam1,2 and Andreas Blaeser2,3
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1 Technical University of Darmstadt, Department of Mechanical Engineering, Institute of Printing Science and Technology, Magdalenenstr. 2, 64289 Darmstadt, Germany
2 Technical University of Darmstadt, Centre for Synthetic Biology, Schnittspahnstr. 10, B2|05, 64287 Darmstadt, Germany
3 Technical University of Darmstadt, Department of Mechanical Engineering, BioMedical Printing Technology, Magdalenenstr. 2, 64289 Darmstadt, Germany
We propose a method to transfer colorimetric assays based on gold nanoparticle aggregation from the laboratory to clinics, practices, or even to an application at home, by creating printed biosensors. While colorimetric assays need laboratory equipment and trained personnel, our printed biosensors (through manual pipetting) are storable, portable and usable from anyone anywhere. The method is verified using a model system for detection of the analyte amino acid cysteine (cys) and a spectral experimental setup in transmission. The model system consists of dispersed gold nanoparticles, which aggregate after cys addition. The biosensor is created by pipetting droplets of a gold nanoparticle solution onto the carrier Hostaphan GN 4600. Its functionality is sustained during the drying process through an addition of glucose, which preserves the gold nanoparticles from aggregation through its amorphous state. The glucose mixture can be kept amorphous over a long time by controlling the surrounding humidity with silica gel beads in an airtight container. The sample mount for the experimental setup is 3D-printed and designed to measure the spectral transmittance of the biosensor before and after analyte addition. The characterization of the setup suggests to expect coefficients of variation below 1 %, which validates its use. The biosensor and transmission spectrometer are tested with analyte concentrations between 10 mM and 50 mM. After a successful verification the printed biosensor would be ready to be evaluated without special equipment, meaning visually or with commercially available imaging techniques. Keeping in mind the possible application at home, the most obvious solution is using your own eyes or smartphone. These methods are discussed in the outlook.
Keywords: spectrometer, gold nanoparticle aggregation, color change, ready to use, printed biosensor
JPMTR 139 | 2006 Original scientific paper
Standardizing milling process parametersfor the narrowest pigment particle size distribution with optimum energy consumption
Shilpa Anchawale, Motupalli (Prasanna) Raghav Rao and Yogesh Nerkar
Department of Printing Engineering, PVG’s College of Engineering and Technology, Savitribai Phule Pune University, Pune, India
Water-based ink, used in production of a new type of green packaging material has an efficient application in the flexible packaging industry to resolve the environmental issues related to volatile organic compound. To get the best possible application properties of dispersed pigment whose performance is mainly measured by the particle size distribution, it is essential to reduce the size of agglomerates. Concentrated dispersed material is manufactured by using a stirred bead mill, which is an energy-intensive process. The process of dispersion must be done efficiently and in the shortest possible time to draw out of the pigment its maximum color properties at the minimum cost. The grinding-energy efficiency is a significant parameter in bead milling as that affects the amount of energy used during grinding of pigment particles. The milling process needs to be optimized to reduce energy consumption. The objective of this study is to determine optimum dispersion process parameters to optimize energy consumption to achieve the narrowest pigment particle size distribution of rubine red pigments used in water-based ink. Experiments were conducted for fine grinding of organic rubine red pigment using a vertical bead mill. The experiments were conducted for varying sizes of grinding media from 0.5 mm to 1.0 mm, for two pigment loadings of 30 % and 37 %, and by extending milling time from 4 h to 6 h. The pigment particle size distribution and power consumption during each trial were measured to optimize process parameters with minimum energy consumption. Response surface design was performed to analyze data. Analysis of variance (ANOVA) techniques were used to check the significance of factors and the interaction of factors. The regression model for specific energy consumption was developed and tested; validation trial for dispersion process parameters concludes that 30 % pigment loading and mixed grinding media size provides narrowest pigment particle size distribution of 128 nm with minimum energy consumption of 1.67 kWh/t.
Keywords: pigment dispersion, bead milling, grinding efficiency, transparency, regression analysis
JPMTR 140 | 2007 Original scientific paper
Tadanobu Sato1 and Craig Revie2
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1 Fujifilm, 2-26-30 Nishi Azabu Minato-ku, Tokyo 106-8620, Japan
2 FFEI Limited, The Cube, Maylands Avenue, Hemel Hempstead, HP2 7DF UK
Recent developments in inkjet technology have enabled the development of high-speed inkjet presses with similar quality and performance to conventional printing presses. These inkjet presses can print on a wide range of papers. Prints made on some papers are of high quality whereas on others are unacceptable. These print results vary from one digital press to another. The focus of this publication is the development of techniques to predict print quality from measurements of papers. Two studies were conducted. In the first, a set of around 250 papers were measured, prints were made on a single digital press and the print quality assessed. In the second, a set of 20 papers were measured, prints were made on three digital presses from different manufacturers and the print quality assessed for each. The studies were unable to identify or develop a single metric that can be used to predict print quality, however, a set of techniques is presented that have been found to be effective predictors of print quality where multiple metrics are used in combination and these methods and results are presented. Both studies adopted a ‘black box’ approach where only the paper measurements and the result of assessment were used to make predictions.
Keywords: inkjet press, print quality, paper property, logistic regression, quality prediction model
JPMTR 141 | 2014 Research paper
Clemson University, 200 L Godfrey Hall, Clemson, SC 29634
In this study, I sought to identify skills, content knowledge, and tools needed in higher education graphic communications programs. Currently a lack of research on the topic of graphic communications competencies exists. The industry is also experiencing a widening scope as well as rapid advancements in technology. The research study utilized a modified Delphi Technique as its method and included participants consisting of full-time graphic communications educators and industry professionals located in the southeast United States. One goal of the study was to gain a consensus among experts regarding what students are expected to know when entering the industry. The purpose of the research was to utilize what experts find to be the most important skills, content knowledge, and tools as a framework for developing and evaluating current higher education graphic communications curriculum. Participants of the study overwhelmingly identified soft skills as being the most needed skills, while software applications were identified as the most needed tools. The results of the project will allow educators to determine whether the current curriculum is preparing students to enter the field.
Keywords: curriculum, employment, evaluation, soft skills, software, tools
JPMTR 142 | 2011 Research paper