3D printing is becoming increasingly prevalent in modern chemistry laboratories. This technology provides chemists with the ability to design, prototype and print functional devices that integrate catalytic and/or analytical functionalities and even to print common laboratory hardware and teaching aids. Although access to 3D printers has increased considerably, some design principles and material considerations need to be weighed before employing such technology in chemistry laboratories. In addition, a certain level of expertise needs to be acquired in order to use computer-aided design, printing software and the specialist hardware associated with higher-end instrumentation. Nonetheless, the recent progress in this field is encouraging, with these printing technologies offering many advantages over traditional production methods. This Review highlights some of the notable advances in this growing area over the past decade. 3D printing is becoming a mainstream technology with considerable increase in access to affordable desktop printers. However, specific design principles and material considerations need to be weighed when printing functional devices that integrate catalytic and/or analytical functionalities, as well as when printing common laboratory hardware.

3D printing for chemical, pharmaceutical and biological applications

3D printing has revolutionized the concept of object manufacturing, making an enormous impact on industry and economy. The technology has found a niche in countless fields, including scientific research. It has rendered practical solutions to scientific problems by offering tailored-shaped devices with exquisite control in design and geometry and through the versatility of printable materials. Applications in analytical and bioanalytical chemistry have been on the rise, with microfluidics being one of the most represented areas of 3D printing towards this chemistry branch. Most stages of the analytical workflow comprising sample collection, pre-treatment and readout, have been enabled by 3D-printed components. Sensor fabrication for detecting explosives and nerve agents, the construction of microfluidic platforms for pharmacokinetic profiling, bacterial separation and genotoxicity screening, the assembly of parts for an on-site equipment for nucleic acid-based detection, the manufacturing of an online device for in vivo detection of metabolites, represent just a few examples of how additive manufacturing technologies have aided the field of (bio)analytical chemistry. In this review, we summarize the most relevant trends of 3D printing applications in this field.

(Bio)Analytical chemistry enabled by 3D printing: Sensors and biosensors

Additive manufacturing with fused deposition modeling (FDM) is currently optimized for a wide range of research and commercial applications. The major disadvantage of FDM-created products is their low quality and structural defects (porosity), which impose an obstacle to utilizing them in functional prototyping and direct digital manufacturing of objects intended to contact with gases and liquids. This article describes a simple and efficient approach for assessing the quality of 3D printed objects. Using this approach it was shown that the wall permeability of a printed object depends on its geometric shape and is gradually reduced in a following series: cylinder > cube > pyramid > sphere > cone. Filament feed rate, wall geometry and G-code-defined wall structure were found as primary parameters that influence the quality of 3D-printed products. Optimization of these parameters led to an overall increase in quality and improvement of sealing properties. It was demonstrated that high quality of 3D printed objects can be achieved using routinely available printers and standard filaments.

Improvement of quality of 3D printed objects by elimination of microscopic structural defects in fused deposition modeling.

3D printing has emerged as a valuable approach for the fabrication of fluidic devices and may replace soft-lithography as the method of choice for rapid prototyping. The potential of this disruptive technology is much greater than this - it allows for functional integration in a single, highly automated manufacturing step in a cost and time effective manner. Integration of functionality with a 3D printer can be done through spatial configuration of a single material, inserting pre-made components mid-print in a print-pause-print approach, and/or through the precise spatial deposition of different materials with a multimaterial printer. This review provides an overview on the ways in which 3D printing has been exploited to create and use fluidic devices with different functionality, which provides a basis for critical reflection on the current deficiencies and future opportunities for integration by 3D printing.

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Increasing the functionalities of 3D printed microchemical devices by single material, multimaterial, and print-pause-print 3D printing

The potential of 3D printing to transform the field of separation science is becoming clear, based upon an increasing capacity to create highly customised devices, materials and structures, with complex geometries. The constantly improving print resolution and increasing variety of available print materials, including functional and composite materials, mean devices can be printed today, which would be extremely challenging to achieve using traditional manufacturing techniques. This review covers the majority of 3D printed devices to-date designed for use within the separation sciences, categorised under application within pre-separation, separation, and post-separation stages of analysis. It describes the impact 3D printing is having on the field, both current and future, recent achievements and challenges, and improvements required to reach its maximum potential as a transformative technology.

Current and future impact of 3D printing on the separation sciences

High-performance thin-layer chromatography (HPTLC) is an advantageous analytical technique for analysis of complex samples. Combined with multivariate data analysis, it turns out to be a powerful tool for profiling of many samples in parallel. So far, chromatogram analysis has been time-consuming and required the application of at least two software packages to convert HPTLC chromatograms into a numerical data matrix. Hence, this study aimed to develop a powerful, all in one open-source software for user-friendly image processing and multivariate analysis of HPTLC chromatograms. Using the caret package for machine learning, the software was set up in the R programming language with an HTML–user interface created by the shiny package. The newly developed software, called rTLC, is deployed online, and instructions for direct use as a web application and for local installation, if required, are available on GitHub. rTLC was created especially for routine use in planar chromatography. It provides the necessar...

/pdf/proof-of-principle-of-rtlc-an-open-source-software-developed-4ueyzlk8qo.pdf

Proof-of-Principle of rTLC, an Open-Source Software Developed for Image Evaluation and Multivariate Analysis of Planar Chromatograms

On the basis of open-source packages, 3D printing of thin silica gel layers is demonstrated as proof-of-principle for use in planar chromatography. A slurry doser was designed to replace the plastic extruder of an open-source Prusa i3 printer. The optimal parameters for 3D printing of layers were studied, and the planar chromatographic separations on these printed layers were successfully demonstrated with a mixture of dyes. The layer printing process was fast. For printing a 0.2 mm layer on a 10 cm × 10 cm format, it took less than 5 min. It was affordable, i.e., the running costs for producing such a plate were less than 0.25 Euro and the investment costs for the modified hardware were 630 Euro. This approach demonstrated not only the potential of the 3D printing environment in planar chromatography but also opened new avenues and new perspectives for tailor-made plates, not only with regard to layer materials and their combinations (gradient plates) but also with regard to different layer shapes and pa...

Open-Source-Based 3D Printing of Thin Silica Gel Layers in Planar Chromatography

An artificial neural network (ANN) is presented as a new and superior technique for processing planar chromatography images. Though several algorithms are available for image processing in planar chromatography, the use of ANN has not been explored so far. It simulates how the human brain interprets images, and the intrinsic features of the image were captured on patches of pixels and successfully reconstructed afterward. The obtained high number of observations was a perfect basis for using ANN. As examples, three quite different data sets were processed with this new algorithm to demonstrate its versatility and benefits. Powerful features, which the ANN learned from the image data set, improved the quality of the analytical data. Thus, noise or inhomogeneous background of bioautograms was removed as demonstrated for salvia extracts, improving their bioquantifications. On colorful fluorescence chromatograms of further botanical extracts, the power and benefit of the feature extraction were demonstrated. ...

Powerful Artificial Neural Network for Planar Chromatographic Image Evaluation, Shown for Denoising and Feature Extraction.

Current high-performance-thin-layer-chromatography instrumentation is offline and stepwise automated However, moderate miniaturization offers many advantages and together with the transfer of modern print and media technologies to the field of chromatography (office chromatography) it opens up new avenues This is demonstrated in an all-in-one open-source system developed for planar chromatography and especially for ultrathin-layer chromatography Using an InkShield board to control a thermal inkjet cartridge, picoliter drops were printed at a resolution of 96 dpi on the adsorbent layer Using Marlin, a popular firmware in 3D printing, Cartesian movement of the print head was made possible for full control of the printing process Open-source software was developed to control the device in each operation step Sample solutions and mobile phase were inkjet-printed, exemplarily shown for the analysis of dye- or paraben-mixture solutions Light-emitting diodes (LEDs) were investigated for documentation For example, deep UV LEDs gave access to 254 nm light, and RGB LEDs gave access to the visible-light range Calibration functions with correlation coefficients superior to 0999 were obtained by videodensitometry The developed modular open-source hardware was compact (26 × 31 × 26 cm3), light (<3 kg), and affordable (€810) For the given analyses, the footprint of current instrumentation needed was miniaturized by a factor of 9 The highly reduced material design complies with green chemistry and lean laboratory The design and instruction to reproduce the all-in-one open-source system were made freely available at https://githubcom/OfficeChromatography  It is intended to boost progress and understanding by the nature of do it yourself

Dimitri Fichou

Papers

Proof-of-Principle of rTLC, an Open-Source Software Developed for Image Evaluation and Multivariate Analysis of Planar Chromatograms

Open-Source-Based 3D Printing of Thin Silica Gel Layers in Planar Chromatography

Powerful Artificial Neural Network for Planar Chromatographic Image Evaluation, Shown for Denoising and Feature Extraction.

Office Chromatography: Miniaturized All-in-One Open-Source System for Planar Chromatography.

quanTLC, an online open-source solution for videodensitometric quantification.