Integrated 3D-printed reactionware for chemical synthesis and analysis

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

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.

Nanoencapsulation of phase change materials for advanced thermal energy storage systems

Phase change materials (PCMs) allow the storage of large amounts of latent heat during phase transition. They have the potential to both increase the efficiency of renewable energies such as solar power through storage of excess energy, which can be used at times of peak demand; and to reduce overall energy demand through passive thermal regulation. 198.3 million tons of oil equivalent were used in the EU in 2013 for heating. However, bulk PCMs are not suitable for use without prior encapsulation. Encapsulation in a shell material provides benefits such as protection of the PCM from the external environment and increased specific surface area to improve heat transfer. This review highlights techniques for the encapsulation of both organic and inorganic PCMs, paying particular attention to nanoencapsulation (capsules with sizes <1 μm). We also provide insight on future research, which should focus on (i) the development of multifunctional shell materials to improve lifespan and thermal properties and (ii) advanced mass manufacturing techniques for the economically viable production of PCM capsules, making it possible to utilize waste heat in intelligent passive thermal regulation systems, employing controlled, "on demand" energy release/uptake.

Open Design 3D-Printable Adjustable Micropipette that Meets the ISO Standard for Accuracy

Scientific communities are drawn to the open source model as an increasingly utilitarian method to produce and share work. Initially used as a means to develop freely-available software, open source projects have been applied to hardware including scientific tools. Increasing convenience of 3D printing has fueled the proliferation of open labware projects aiming to develop and share designs for scientific tools that can be produced in-house as inexpensive alternatives to commercial products. We present our design of a micropipette that is assembled from 3D-printable parts and some hardware that works by actuating a disposable syringe to a user-adjustable limit. Graduations on the syringe are used to accurately adjust the set point to the desired volume. Our open design printed micropipette is assessed in comparison with a commercial pipette and meets the ISO 8655 standards.

Biodegradable 3D printed polymer microneedles for transdermal drug delivery

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1-55 μm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.

3D-Printed Graphene/Polylactic Acid Electrodes Promise High Sensitivity in Electroanalysis

Additive manufacturing provides a unique tool for prototyping structures toward electrochemical sensing, due to its ability to produce highly versatile, tailored-shaped devices in a low-cost and fast way with minimized waste. Here we present 3D-printed graphene electrodes for electrochemical sensing. Ring- and disc-shaped electrodes were 3D-printed with a Fused Deposition Modeling printer and characterized using cyclic voltammetry and scanning electron microscopy. Different redox probes K₃Fe(CN)₆:K₄Fe(CN)₆, FeCl₃, ascorbic acid, Ru(NH₃)₆Cl₃, and ferrocene monocarboxylic acid) were used to assess the electrochemical performance of these devices. Finally, the electrochemical detection of picric acid and ascorbic acid was carried out as proof-of-concept analytes for sensing applications. Such customizable platforms represent promising alternatives to conventional electrodes for a wide range of sensing applications.

3D printing of graphene-doped target for "matrix-free" laser desorption/ionization mass spectrometry

We report a graphene-doped resin target fabricated via a 3D printing technique for laser desorption/ionization mass spectrometry analysis. The graphene doped in the target acts as an inherent laser absorber and ionization promoter, thus permitting the direct analysis of samples without adding matrix. This work reveals a new strategy for easy designing and fabrication of functional mass spectrometry devices.

A Modular Microfluidic Device via Multimaterial 3D Printing for Emulsion Generation

3D-printing (3DP) technology has been developing rapidly. However, limited studies on the contribution of 3DP technology, especially multimaterial 3DP technology, to droplet-microfluidics have been reported. In this paper, multimaterial 3D-printed devices for the pneumatic control of emulsion generation have been reported. A 3D coaxial flexible channel with other rigid structures has been designed and printed monolithically. Numerical and experimental studies have demonstrated that this flexible channel can be excited by the air pressure and then deform in a controllable way, which can provide the active control of droplet generation. Furthermore, a novel modular microfluidic device for double emulsion generation has been designed and fabricated, which consists of three modules: function module, T-junction module, and co-flow module. The function module can be replaced by (1) Single-inlet module, (2) Pneumatic Control Unit (PCU) module and (3) Dual-inlet module. Different modules can be easily assembled for different double emulsion production. By using the PCU module, double emulsions with different number of inner droplets have been successfully produced without complicated operation of flow rates of different phases. By using single and dual inlet module, various double emulsions with different number of encapsulated droplets or encapsulated droplets with different compositions have been successfully produced, respectively.

Water decontamination by polyoxometalate-functionalized 3D-printed hierarchical porous devices

The design of organic-inorganic hybrid composites has revolutionized application-driven materials design. Here, we show how hierarchically structured, 3D-printed ABS polymers can be surface-functionalized with lacunary polyoxometalate anions ([α-PW₉O₃₄]^9-) featuring heavy-metal binding sites. The resulting composite is highly porous and can be used for the removal of transition-metal pollutants from water. Thus, a facile blueprint for decentralized production of water filtration devices is reported.

3D printing in chemical engineering and catalytic technology: structured catalysts, mixers and reactors

Computer-aided fabrication technologies combined with simulation and data processing approaches are changing our way of manufacturing and designing functional objects. Also in the field of catalytic technology and chemical engineering the impact of additive manufacturing, also referred to as 3D printing, is steadily increasing thanks to a rapidly decreasing equipment threshold. Although still in an early stage, the rapid and seamless transition between digital data and physical objects enabled by these fabrication tools will benefit both research and manufacture of reactors and structured catalysts. Additive manufacturing closes the gap between theory and experiment, by enabling accurate fabrication of geometries optimized through computational fluid dynamics and the experimental evaluation of their properties. This review highlights the research using 3D printing and computational modeling as digital tools for the design and fabrication of reactors and structured catalysts. The goal of this contribution is to stimulate interactions at the crossroads of chemistry and materials science on the one hand and digital fabrication and computational modeling on the other.

Prolongation of liver-specific function for primary hepatocytes maintenance in 3D printed architectures

Isolated primary hepatocytes from the liver are very similar to in vivo native liver hepatocytes, but they have the disadvantage of a limited lifespan in 2D culture. Although a sandwich culture and 3D organoids with mesenchymal stem cells (MSCs) as an attractive assistant cell source to extend lifespan can be used, it cannot fully reproduce the in vivo architecture. Moreover, long-term 3D culture leads to cell death because of hypoxic stress. Therefore, to overcome the drawback of 2D and 3D organoids, we try to use a 3D printing technique using alginate hydrogels with primary hepatocytes and MSCs. The viability of isolated hepatocytes was more than 90%, and the cells remained alive for 7 days without morphological changes in the 3D hepatic architecture with MSCs. Compared to a 2D system, the expression level of functional hepatic genes and proteins was higher for up to 7 days in the 3D hepatic architecture. These results suggest that both the 3D bio-printing technique and paracrine molecules secreted by MSCs supported long-term culture of hepatocytes without morphological changes. Thus, this technique allows for widespread expansion of cells while forming multicellular aggregates, may be applied to drug screening and could be an efficient method for developing an artificial liver.

Three-Dimensional Bioprinting Strategies for Tissue Engineering

Over the past decades, many approaches have been developed to fabricate biomimetic extracellular matrices of desired properties for engineering functional tissues. However, the inability of these techniques to precisely control the spatial architecture has posed a significant challenge in producing complex tissues. 3D bioprinting technology has emerged as a potential solution by bringing unprecedented freedom and versatility in depositing biological materials and cells in a well-controlled manner in the 3D volumes, therefore achieving precision engineering of functional tissues. In this article, we review the application of 3D bioprinting to tissue engineering. We first discuss the general strategies for printing functional tissue constructs. We next describe different types of bioprinting with a focus on nozzle-based techniques and their respective advantages. Finally, we summarize the limitations of current technologies and propose challenges for future development of bioprinting.

pH-Controlled One Pot Syntheses of Giant Mo2O2S2-Containing Seleno-Tungstate Architectures

Self-assembly reactions of Na₂WO₄, SeO₂/SeO₃^2-, and [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ give, depending on the pH value, two new large polyoxometalate complexes: i.e., [(γ-Se₂W₁₄O₅₂)₃(Mo₂O₂(μ-S)₂(H₂O)₂)₆]^24- (1) isolated at pH 3.5 and [(γ-Se₂W₁₄O₅₂)₄(WO₃(H₂O))₈(W₂O₅)₂(W₄O₁₂)₂(Mo₂O₂(μ-S)₂(H₂O)₂)₄(Mo₂O₂(μ-S)₂(SeO₃))₄]^36- (2) isolated at pH 2. Both compounds were characterized in the solid state by single-crystal X-ray diffraction, EDX, elemental analysis, TGA, and FT-IR and in solution by ESI-MS and NMR.

Three-Dimensional Printing with Biomass-Derived PEF for Carbon-Neutral Manufacturing

Biomass-derived poly(ethylene-2,5-furandicarboxylate) (PEF) has been used for fused deposition modeling (FDM) 3D printing. A complete cycle from cellulose to the printed object has been performed. The printed PEF objects created in the present study show higher chemical resistance than objects printed with commonly available materials (acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), glycol-modified poly(ethylene terephthalate) (PETG)). The studied PEF polymer has shown key advantages for 3D printing: optimal adhesion, thermoplasticity, lack of delamination and low heat shrinkage. The high thermal stability of PEF and relatively low temperature that is necessary for extrusion are optimal for recycling printed objects and minimizing waste. Several successive cycles of 3D printing and recycling were successfully shown. The suggested approach for extending additive manufacturing to carbon-neutral materials opens a new direction in the field of sustainable development.

Generation of Multilayered 3D Structures of HepG2 Cells Using a Bio-printing Technique

Background/Aims

Chronic liver disease is a major widespread cause of death, and whole liver transplantation is the only definitive treatment for patients with end-stage liver diseases. However, many problems, including donor shortage, surgical complications and cost, hinder their usage. Recently, tissue-engineering technology provided a potential breakthrough for solving these problems. Three-dimensional (3D) printing technology has been used to mimic tissues and organs suitable for transplantation, but applications for the liver have been rare.

Methods

A 3D bioprinting system was used to construct 3D printed hepatic structures using alginate. HepG2 cells were cultured on these 3D structures for 3 weeks and examined by fluorescence microscopy, histology and immunohistochemistry. The expression of liver-specific markers was quantified on days 1, 7, 14, and 21.

Results

The cells grew well on the alginate scaffold, and liver-specific gene expression increased. The cells grew more extensively in 3D culture than two-dimensional culture and exhibited better structural aspects of the liver, indicating that the 3D bioprinting method recapitulates the liver architecture.

Conclusions

The 3D bioprinting of hepatic structures appears feasible. This technology may become a major tool and provide a bridge between basic science and the clinical challenges for regenerative medicine of the liver.

3D printed device including disk-based solid-phase extraction for the automated speciation of iron using the multisyringe flow injection analysis technique

The development of advanced manufacturing techniques is crucial for the design of novel analytical tools with unprecedented features. Advanced manufacturing, also known as 3D printing, has been explored for the first time to fabricate modular devices with integrated features for disk-based automated solid-phase extraction (SPE). A modular device integrating analyte oxidation, disk-based SPE and analyte complexation has been fabricated using stereolithographic 3D printing. The 3D printed device is directly connected to flow-based analytical instrumentation, replacing typical flow networks based on discrete elements. As proof of concept, the 3D printed device was implemented in a multisyringe flow injection analysis (MSFIA) system, and applied to the fully automated speciation, SPE and spectrophotometric quantification of Fe in water samples. The obtained limit of detection for total Fe determination was 7ng, with a dynamic linear range from 22ng to 2400ng Fe (3mL sample). An intra-day RSD of 4% (n = 12) and an inter-day RSD of 4.3% (n = 5, 3mL sample, different day with a different disk), were obtained. Incorporation of integrated 3D printed devices with automated flow-based techniques showed improved sensitivity (85% increase on the measured peak height for the determination of total Fe) in comparison with analogous flow manifolds built from conventional tubing and connectors. Our work represents a step forward towards the improved reproducibility in the fabrication of manifolds for flow-based automated methods of analysis, which is especially relevant in the implementation of interlaboratory analysis.

Biomimetic molecular design tools that learn, evolve, and adapt

A dominant hallmark of living systems is their ability to adapt to changes in the environment by learning and evolving. Nature does this so superbly that intensive research efforts are now attempting to mimic biological processes. Initially this biomimicry involved developing synthetic methods to generate complex bioactive natural products. Recent work is attempting to understand how molecular machines operate so their principles can be copied, and learning how to employ biomimetic evolution and learning methods to solve complex problems in science, medicine and engineering. Automation, robotics, artificial intelligence, and evolutionary algorithms are now converging to generate what might broadly be called in silico-based adaptive evolution of materials. These methods are being applied to organic chemistry to systematize reactions, create synthesis robots to carry out unit operations, and to devise closed loop flow self-optimizing chemical synthesis systems. Most scientific innovations and technologies pass through the well-known "S curve", with slow beginning, an almost exponential growth in capability, and a stable applications period. Adaptive, evolving, machine learning-based molecular design and optimization methods are approaching the period of very rapid growth and their impact is already being described as potentially disruptive. This paper describes new developments in biomimetic adaptive, evolving, learning computational molecular design methods and their potential impacts in chemistry, engineering, and medicine.

An autonomous organic reaction search engine for chemical reactivity

The exploration of chemical space for new reactivity, reactions and molecules is limited by the need for separate work-up-separation steps searching for molecules rather than reactivity. Herein we present a system that can autonomously evaluate chemical reactivity within a network of 64 possible reaction combinations and aims for new reactivity, rather than a predefined set of targets. The robotic system combines chemical handling, in-line spectroscopy and real-time feedback and analysis with an algorithm that is able to distinguish and select the most reactive pathways, generating a reaction selection index (RSI) without need for separate work-up or purification steps. This allows the automatic navigation of a chemical network, leading to previously unreported molecules while needing only to do a fraction of the total possible reactions without any prior knowledge of the chemistry. We show the RSI correlates with reactivity and is able to search chemical space using the most reactive pathways.

While automated reaction systems typically work for the synthesis of pre-defined molecules, automated systems to discover reactivity are more challenging. Here the authors report an autonomous organic reaction search engine that allows discovery of the most reactive pathways in a multi-reagent, multistep reaction system.

The Hitchhiker's Guide to Flow Chemistry ∥

Flow chemistry involves the use of channels or tubing to conduct a reaction in a continuous stream rather than in a flask. Flow equipment provides chemists with unique control over reaction parameters enhancing reactivity or in some cases enabling new reactions. This relatively young technology has received a remarkable amount of attention in the past decade with many reports on what can be done in flow. Until recently, however, the question, "Should we do this in flow?" has merely been an afterthought. This review introduces readers to the basic principles and fundamentals of flow chemistry and critically discusses recent flow chemistry accounts.

Emerging Droplet Microfluidics

Droplet microfluidics generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels. Due to its remarkable advantages, droplet microfluidics bears significant value in an extremely wide range of area. In this review, we provide a comprehensive and in-depth insight into droplet microfluidics, covering fundamental research from microfluidic chip fabrication and droplet generation to the applications of droplets in bio(chemical) analysis and materials generation. The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development. We believe this review will promote communications among biology, chemistry, physics, and materials science.

High Performance, Low Cost Carbon Nanotube Yarn based 3D Printed Electrodes Compatible with a Conventional Screen Printed Electrode System

3D printing technology has been widely used as a rapid prototyping fabrication tool in several fields, including electrochemistry. In this work, we incorporate 3D printing technology with carbon nanotube yarns for electrochemical sensing of dopamine in the presence of ascorbic acid and uric acid. The novel 3D printed electrode provides a circular concavity detection zone with grooves to insert three electrodes. The electrode connections are fully compatible with conventional screen printed electrode workstation setups. The CNT yarn 3D printed electrode showed excellent electrocatalytic activity for the redox reaction of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA). Three well-defined sharp and fully resolved anodic peaks were found with the peak potentials using cyclic voltammetry (CV) at 50 mV, 305 mV, and 545 mV for AA, DA, and UA respectively and using differential pulse voltammetry (DPV) at 91 mV, 389 mV, and 569 mV, respectively. DA detection limit was 0.87 ± 0.09 μM. The CNT yarn 3D printed electrode displayed high reproducibility and stability. The electrode design enables the study of electrode reactions at the sidewall of CNTs, which cannot be performed using electrodes made by conventional fabrication methods. The new fabrication method provides a new platform to prototype new electrode materials for electrochemistry, providing a low-cost, customizable design compatible existing screen printed electrodes technology.

Microfluidic EBG Sensor Based on Phase-Shift Method Realized Using 3D Printing Technology

In this article, we propose a novel microfluidic microstrip electromagnetic band gap (EBG) sensor realized using cost-effective 3D printing technology. Microstrip sensor allows monitoring of the fluid properties flowing in the microchannel embedded between the microstrip line and ground plane. The sensor’s operating principle is based on the phase-shift method, which allows the characterization at a single operating frequency of 6 GHz. The defected electromagnetic band gap (EBG) structure is realized as a pattern in the microstrip ground plane to improve sensor sensitivity. The designed microfluidic channel is fabricated using a fused deposition modelling (FDM) 3D printing process without additional supporting layers, while the conductive layers are realized using sticky aluminium tape. The measurement results show that the change of permittivity of the fluid in the microfluidic channel from 1 to 80 results in the phase-shift difference of almost 90°. The potential application is demonstrated through the implementation of a proposed sensor for the detection of toluene concentration in toluene–methanol mixture where various concentrations of toluene were analysed.

3D-Printed High-Density Droplet Array Chip for Miniaturized Protein Crystallization Screening under Vapor Diffusion Mode

Here we describe the combination of three-dimensional (3D) printed chip and automated microfluidic droplet-based screening techniques for achieving massively parallel, nanoliter-scale protein crystallization screening under vapor diffusion mode. We fabricated high-density microwell array chips for sitting-drop vapor diffusion crystallization utilizing the advantage of the 3D-printing technique in producing high-aspect-ratio chips. To overcome the obstacle of 3D-printed microchips in performing long-term reactions caused by their porousness and gas permeability properties in chip body, we developed a two-step postprocessing method, including paraffin filling and parylene coating, to achieve high sealability and stability. We also developed a simple method especially suitable for controlling the vapor diffusion speed of nanoliter-scale droplets by changing the layer thickness of covering oil. With the above methods, 84 tests of nanoliter-scale protein crystallization under vapor diffusion mode were successfully achieved in the 7 × 12 droplet array chip with a protein consumption of 10 nL for each test, which is 20-100 times lower than that in the conventional large-volume screening system. Such a nanoliter-scale vapor diffusion system was applied to two model proteins with commercial precipitants and displayed advantages over that under microbatch mode. It identified more crystallization conditions, especially for the protein samples with lower concentrations.

Stereoselective Catalytic Synthesis of Active Pharmaceutical Ingredients in Homemade 3D-Printed Mesoreactors

3D-printed flow reactors were designed, fabricated from different materials (PLA, HIPS, nylon), and used for a catalytic stereoselective Henry reaction. The use of readily prepared and tunable 3D-printed reactors enabled the rapid screening of devices with different sizes, shapes, and channel dimensions, aimed at the identification of the best-performing reactor setup. The optimized process afforded the products in high yields, moderate diastereoselectivity, and up to 90 % ee. The method was applied to the continuous-flow synthesis of biologically active chiral 1,2-amino alcohols (norephedrine, metaraminol, and methoxamine) through a two-step sequence combining the nitroaldol reaction with a hydrogenation. To highlight potential industrial applications of this method, a multistep continuous synthesis of norephedrine has been realized. The product was isolated without any intermediate purifications or solvent switches.

Comparing Microfluidic Performance of Three-Dimensional (3D) Printing Platforms

Three-dimensional (3D) printing has emerged as a potential revolutionary technology for the fabrication of microfluidic devices. A direct experimental comparison of the three 3D printing technologies dominating microfluidics was conducted using a Y-junction microfluidic device, the design of which was optimized for each printer: fused deposition molding (FDM), Polyjet, and digital light processing stereolithography (DLP-SLA). Printer performance was evaluated in terms of feature size, accuracy, and suitability for mass manufacturing; laminar flow was studied to assess their suitability for microfluidics. FDM was suitable for microfabrication with minimum features of 321 ± 5 μm, and rough surfaces of 10.97 μm. Microfluidic devices >500 μm, rapid mixing (71% ± 12% after 5 mm, 100 μL/min) was observed, indicating a strength in fabricating micromixers. Polyjet fabricated channels with a minimum size of 205 ± 13 μm, and a surface roughness of 0.99 μm. Compared with FDM, mixing decreased (27% ± 10%), but Polyjet printing is more suited for microfluidic applications where flow splitting is not required, such as cell culture or droplet generators. DLP-SLA fabricated a minimum channel size of 154 ± 10 μm, and 94 ± 7 μm for positive structures such as soft lithography templates, with a roughness of 0.35 μm. These results, in addition to low mixing (8% ± 1%), showed suitability for microfabrication, and microfluidic applications requiring precise control of flow. Through further discussion of the capabilities (and limitations) of these printers, we intend to provide guidance toward the selection of the 3D printing technology most suitable for specific microfluidic applications.

3D Printed Graphene Based Energy Storage Devices

3D printing technology provides a unique platform for rapid prototyping of numerous applications due to its ability to produce low cost 3D printed platforms. Herein, a graphene-based polylactic acid filament (graphene/PLA) has been 3D printed to fabricate a range of 3D disc electrode (3DE) configurations using a conventional RepRap fused deposition moulding (FDM) 3D printer, which requires no further modification/ex-situ curing step. To provide proof-of-concept, these 3D printed electrode architectures are characterised both electrochemically and physicochemically and are advantageously applied as freestanding anodes within Li-ion batteries and as solid-state supercapacitors. These freestanding anodes neglect the requirement for a current collector, thus offering a simplistic and cheaper alternative to traditional Li-ion based setups. Additionally, the ability of these devices’ to electrochemically produce hydrogen via the hydrogen evolution reaction (HER) as an alternative to currently utilised platinum based electrodes (with in electrolysers) is also performed. The 3DE demonstrates an unexpectedly high catalytic activity towards the HER (−0.46 V vs. SCE) upon the 1000th cycle, such potential is the closest observed to the desired value of platinum at (−0.25 V vs. SCE). We subsequently suggest that 3D printing of graphene-based conductive filaments allows for the simple fabrication of energy storage devices with bespoke and conceptual designs to be realised.

Direct Production of Microstructured Surfaces for Planar Chromatography Using 3D Printing

Through optimization of the printing process and orientation, a suitably developed surface area has been realized upon a 3D printed polymer substrate to facilitate chromatographic separations in a planar configuration. Using an Objet Eden 260VS 3D printer, polymer thin layer chromatography platforms were directly fabricated without any additional surface functionalization and successfully applied to the separation of various dye and protein mixtures. The print material was characterized using gas chromatography coupled to mass spectrometry and spectroscopic techniques such as infrared and Raman. Preliminary studies included the separation of colored dyes, whereby the separation performance could be visualized optically. Subsequent separations were achieved using fluorescent dyes and fluorescently tagged proteins. The separation of proteins was affected by differences in the isoelectric point (pI) and the ion exchange properties of the printed substrate. The simple chromatographic separations are the first achieved using an unmodified 3D printed stationary phase.

Application of 3D printing to prototype and develop novel plant tissue culture systems

BACKGROUND

Due to the complex process of designing and manufacturing new plant tissue culture vessels through conventional means there have been limited efforts to innovate improved designs. Further, development and availability of low cost, energy efficient LEDs of various spectra has made it a promising light source for plant growth in controlled environments. However, direct replacement of conventional lighting sources with LEDs does not address problems with uniformity, spectral control, or the challenges in conducting statistically valid experiments to assess the effects of light. Prototyping using 3D printing and LED based light sources could help overcome these limitations and lead to improved culture systems.

RESULTS

A modular culture vessel design in which the fluence rate and spectrum of light are independently controlled was designed, prototyped using 3D printing, and evaluated for plant growth. This design is compatible with semi-solid and liquid based culture systems. Observations on morphology, chlorophyll content, and chlorophyll fluorescence based stress parameters from in vitro plants cultured under different light spectra with similar overall fluence rate indicated different responses in Nicotiana tabacum and Artemisia annua plantlets. This experiment validates the utility of 3D printing to design and test functional vessels and demonstrated that optimal light spectra for in vitro plant growth is species-specific.

CONCLUSIONS

3D printing was successfully used to prototype novel culture vessels with independently controlled variable fluence rate/spectra LED lighting. This system addresses several limitations associated with current lighting systems, providing more uniform lighting and allowing proper replication/randomization for experimental plant biology while increasing energy efficiency. A complete procedure including the design and prototyping of a culture vessel using 3D printing, commercial scale injection molding of the prototype, and conducting a properly replicated experiment are discussed. This open source design has the scope for further improvement and adaptation and demonstrates the power of 3D printing to improve the design of culture systems.

Combining additive manufacturing and catalysis: a review

A review on additive manufacturing (AM) applied to heterogeneous catalysis reveals enabling power of AM and challenges to overcome in chemical interfacing and material printability.

Nanowire enhanced dimensional accuracy in acrylate resin-based 3D printing

3D printing accuracy can be remarkably enhanced by incorporating nanowires into photopolymerizable resins through the elimination of curl distortion.

Advanced reactor engineering with 3D printing for the continuous-flow synthesis of silver nanoparticles

3D printing has been employed to manufacture advanced reactor geometries based on miniaturised continuous-flow oscillatory baffled reactors (mCOBRs) and they have been applied for the fouling free continuous-flow synthesis of silver nanoparticles with optimal size control.