The potentials of additive manufacturing for mass production of electrochemical energy systems

Additive manufacturing has established itself as a popular and powerful tool in electrochemistry research and development. In this short review, we focus on the latest results in both 3D printing and electrochemistry communities that could potentially benefit manufacturing in the electrochemical industry. We provide insights from recent and relevant research works and conclude that the likely scenario in the industry is the deployment of a combination of subtractive and additive technologies in order to manufacture high quality and cost-effective electrochemical reactors within reasonable timeframes.     

3D-printed electrochemical sensors: A new horizon for measurement of biomolecules

Electrochemical sensors are widely used to monitor biomolecules. However, limitations in sensor geometry have restricted the scope of currently used electrochemical sensors. 3D-printing has emerged as a promising manufacturing approach, to robustly make electrochemical sensors, that can stably measure in biological environments. This review highlights the recent trends in the development of 3D-printed electrodes and biosensors for measurement of biomolecules. Novel geometries of 3D-printed electrodes have provided the means to conduct ex vivo measurement in the intestinal tract and in vivo measurements in the brain. 3D-printing is providing the ability to manufacture electrochemical sensors that can measure biomolecules in diverse areas of the body.     

Additive manufacturing for energy storage: Methods,designs and material selection for customizable 3D printed batteries and supercapacitors

Additive manufacturing and 3D printing in particular have the potential to revolutionize existing fabrication processes, where objects with complex structures and shapes can be built with multifunctional material systems. For electrochemical energy storage devices such as batteries and supercapacitors, 3D printing methods allows alternative form factors to be conceived based on the end use application need in mind at the design stage. Additively manufactured energy storage devices require active materials and composites that are printable, and this is influenced by performance requirements and the basic electrochemistry. The interplay between electrochemical response, stability, material type, object complexity and end use application are key to realising 3D printing for electrochemical energy storage. Here, we summarise recent advances and highlight the important role of methods, designs and material selection for energy storage devices made by 3D printing, which is general to the majority of methods in use currently.     

3D printing for aqueous and non-aqueous redox flow batteries

Additive manufacturing technologies, generally grouped under the name of 3D printing, are experiencing an explosion of interest during the last few years. The possibility of fast prototyping enabled by 3D printing has been recognized as a crucial booster for device fabrication and general scientific advancements. In this review, attention is focused on the latest developments in the field of redox flow batteries which are, similar to other energy related devices, characterized by the recent adoption of 3D printing methods for the fabrication of key components. Whether simply to investigate flow phenomena, test new designs or fabricate final-product components with custom features, the use of 3D printing can critically drive this field of research towards better performing energy-storage systems. The latest and most representative examples of redox flow battery studies will be discussed, categorized in relation to the electrolyte used and whether the devices are employed in aqueous or non-aqueous applications.     

Fracture resistance measurement of fused deposition modeling 3D printed polymers

A method is presented to characterize the fracture resistance and interlayer adhesion of fused deposition modeling (FDM) 3D printed materials. Double cantilever beam (DCB) specimens of acrylonitrile butadiene styrene (ABS) were designed and printed with a precrack at the layers' interface. The DCBs were loaded in an opening mode and the load-displacement curves were synchronized with the optical visualization of the crack tip to detect the critical load at the crack initiation. A finite element model, coupled with J-integral method and fracture surface analysis was then developed to obtain the apparent fracture resistance (J_cr,a) and the interlayer fracture resistance (J_cr,i), as a measure of the interlayer adhesion. The maximum J_cr,i was measured to be 4017 J/m², a value close to the fracture resistance of bulk ABS. Both J_cr,a and J_cr,i increased with the printing temperature. This method can find a great importance in the structural applications of printed materials.     

3D printed polylactic acid nanocomposite scaffolds for tissue engineering applications

In this study, biodegradable polylactic acid (PLA) and PLA nanocomposite scaffolds reinforced with magnetic and conductive fillers, were processed via fused filament fabrication additive manufacturing and their bioactivity and biodegradation characteristics were examined. Porous 3D architectures with 50% bulk porosity were 3D printed, and their physicochemical properties were evaluated. Thermal analysis confirmed the presence of ~18 wt% of carbon nanostructures (CNF and GNP; nowonwards CNF) and ~37 wt% of magnetic iron oxide (Fe₂O₃) particles in the filaments. The in vitro degradation tests of scaffolds showed porous and fractured struts after 2 and 4 weeks of immersion in DMEM respectively, although a negligible weight loss is observed. Greater extent of degradation is observed in PLA with magnetic fillers followed by PLA with conductive fillers and neat PLA. In vitro bioactivity study of scaffolds indicate enhancement from ~2.9% (PLA) to ~5.32% (PLA/CNF) and ~ 3.12% (PLA/Fe₂O₃). Stiffness calculated from the compression tests showed decrease from ~680 MPa (PLA) to 533 MPa and 425 MPa for PLA/CNF and PLA/Fe₂O₃ respectively. Enhanced bioactivity and faster biodegradation response of PLA nanocomposites with conductive fillers make them a potential candidate for tissue engineering applications such as scaffold bone replacement and regeneration.     

Development of 3D printed mesofluidic devices to elute and concentrate DNA

To understand structural variation for personal genomics, an extensive ensemble of large DNA molecules will be required to span large structural variations. Nanocoding, a whole‐genome analysis platform, can analyze large DNA molecules for the construction of physical restriction maps of entire genomes. However, handling of large DNA is difficult and a system is needed to concentrate large DNA molecules, while keeping the molecules intact. Insert technology was developed to protect large DNA molecules during routine cell lysis and molecular biology techniques. However, eluting and concentrating DNA molecules has been difficult in the past. Utilizing 3D printed mesofluidic device, a proof of principle system was developed to elute and concentrate lambda DNA molecules at the interface between a solution and a poly‐acrylamide roadblock. The matrix allowed buffer solution to move through the pores in the matrix; however, it slowed down the progression of DNA in the matrix, since the molecules were so large and the pore size was small. Using fluorescence intensity of the insert, 84% of DNA was eluted from the insert and 45% of DNA was recovered in solution from the eluted DNA. DNA recovered was digested with a restriction enzyme to determine that the DNA molecules remained full length during the elution and concentration of DNA.     

Rapid prototyping of electrochemical energy storage devices based on two dimensional materials

Rapid prototyping methods such as additive manufacturing (three dimensional printing) and laser scribing have attracted much attention for manufacturing next-generation electrochemical energy storage devices because of their simplicity, low cost, medium throughput, and ability to prepare electrodes with unique form factors and multiple functionalities, such as stretchability, flexibility, and wearability. Of the wide array of potential active materials that can be used for energy storage, two dimensional materials such as graphene, MXenes, and MoS₂ have exceptionally high conductive surface areas and are attractive candidates for printing thick, high loading supercapacitors and batteries. In this brief review, we highlight recent progress and major challenges which must be overcome to make these manufacturing approaches and the resulting printed devices commercially viable.     

Concentration of lambda concatemers using a 3D printed device

Identifying significant variations in genomes can be cumbersome, as the variations span a multitude of base pairs and can make genome assembly difficult. However, large DNA molecules that span the variation aid in assembly. Due to the DNA molecule's large size, routine molecular biology techniques can break DNA. Therefore, a method is required to concentrate large DNA. A bis-acrylamide roadblock was cured in a proof-of-principle 3D printed device to concentrate DNA at the interface between the roadblock and solution. Lambda concatemer DNA was stained with YOYO-1 and loaded into the 3D printed device. A dynamic range of voltages and acrylamide concentrations were tested to determine how much DNA was concentrated and recovered. The fluorescence of the original solution and the concentrated solution was measured, the recovery was 37% of the original sample, and the volume decreased by a factor of 3 of the original volume.     

Discrete DNA three-dimensional nanostructures: the synthesis and applications

Structural DNA nanotechnology, an emerging technique that utilizes the nucleic acid molecule as generic polymer to programmably assemble well-defined and nano-sized architectures, holds great promise for new material synthesis and constructing functional nanodevices for different purposes. In the past three decades, rapid development of this technique has enabled the syntheses of hundreds and thousands of DNA nanostructures with various morphologies at different scales and dimensions. Among them, discrete three-dimensional (3D) DNA nanostructures not only represent the most advances in new material design, but also can serve as an excellent platform for many important applications. With precise spatial addressability and capability of arbitrary control over size, shape, and function, these nanostructures have drawn particular interests to scientists in different research fields. In this review article, we will briefly summarize the development regarding the synthesis of discrete DNA 3D nanostructures with various size, shape, geometry, and topology, including our previous work and recent progress by other groups. In detail, three methods majorly used to synthesize the DNA 3D objects will be introduced accordingly. Additionally, the principle, design rule, as well as pros and cons of each method will be highlighted. As functions of these discrete 3D nanostructures have drawn great interests to researchers, we will further discuss their cutting-edge applications in different areas, ranging from novel material synthesis, new device fabrication, and biomedical applications, etc. Lastly, challenges and outlook of these promising nanostructures will be given based on our point of view.     

TTF-TCNQ complex based printed biosensor for long-term operation

A printed amperometric glucose sensor based on glucose oxidase adsorbed on crystals of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) is described. The sensitivity and the stability of the sensor are affected by the binder and solvent used for the preparation of the GOD.TTF-TCNQ paste. The sensors are continuously used in a flow injection analysis (FIA) system under continuous polarization at 0.15 V (vs Ag/AgCl) at 37°C. The developed sensors exhibit a large response current, an extended linear range and oxygen independence. The sensors can be used for more than 3 months. The GOD.TTF-TCNQ paste is suitable for the preparation of planar sensor by screen printing method.     

Present status of the functional advanced micro-, nano-printings – a mini review

Additive printing technology and expertise have experienced noteworthy development driven by their ability to revolutionize academic and industrial manufacturing and research. They also have particular practical uses in the areas of micro and nanofabrication. Micro- and nano-printings have found a tremendous number of applications in material synthesis/patterning, electronics, medicine and biotechnology. In this mini review, we examine the important additive micro and nano printing techniques, including contact and noncontact, and roll to roll (R2R) printing methods as well as recently emerging techniques such as micro- or nano-pen printings, laser-induced forward transfer (LIFT) and aerosol jet printing (APJ). We also discuss the materials that are printable by these technologies, the applications of micro- and nano-printings, key features, advantages and challenges.     

Rational design and biomedical applications of DNA-functionalized upconversion nanoparticles

In this review, we mainly introduced recent progress of DNA-functionalized upconversion materials, providing an overview of the design and applications in biosensing, bioimaging and disease therapy. The challenges and future perspectives are also discussed, aiming to promote their applications in materials science and biomedicine.     

Architected porous metals in electrochemical energy storage

Porous metallic structures are regularly used in electrochemical energy storage (EES) devices as supports, current collectors, or active electrode materials. Bulk metal porosification, dealloying, welding, or chemical synthesis routes involving crystal growth or self-assembly, for example, can sometimes provide limited control of porous length scale, ordering, periodicity, reproducibility, porosity, and surface area. Additive manufacturing has shown the potential to revolutionize the fabrication of architected metals, allowing complex geometries not usually possible by traditional methods, by enabling complete design freedom of a porous metal based on the required physical or chemical property to be exploited. We discuss properties of porous metal structures in EES devices and provide some opinions on how architected metals may alleviate issues with electrochemically active porous metal current collectors, and provide opportunities for optimum design based on electrochemical characteristics required by batteries, supercapacitors or other electrochemical devices.     

Investigation of the regeneration of the passive surface oxide layer of TiAl6V4 alloy printed by WAAM technology using different electrochemical test methods

The kinetics of oxide layer formation on surface of Ti6Al4V alloy samples is a very important property especially if their application as medical implants is planned. Damaged protective surface layer usually heals in ambient condition however; during the self-healing process toxic species can get into the surrounding living tissue. In our experiment the kinetics of the healing process proceeding at 3D printed alloy surface has been studied using electrochemical methods, among them scanning electrochemical microscopy. More than 40 min. time period was found long enough for total healing.     

A novel sensitive electrochemical DNA biosensor for assaying of anticancer drug leuprolide and its adsorptive stripping voltammetric determination

The anticancer drug, leuprolide (LPR) bound to double-stranded fish sperm DNA (dsDNA) which was immobilized onto the surface of an anodically activated pencil graphite electrode (PGE), was employed for designing a sensitive biosensor. The interaction of leuprolide (LPR) with double-stranded DNA (dsDNA) immobilized onto pencil graphite electrode (PGE) have been studied by electrochemical methods. The mechanism of the interaction was investigated and confirmed by differential pulse voltammetry using two different interaction methods; at the PGE surface and in the solution phase. The decrease in the guanine oxidation peak current was used as an indicator for the interaction in acetate buffer at pH 4.80. The response was optimized with respect to accumulation time, potential, drug concentration, and reproducibility for both interaction methods. The linear response was obtained in the range of 0.20-6.00 ppm LPR concentration with a detection limit of 0.06 ppm on DNA modified PGE and between 0.20 and 1.00 ppm concentration range with detection limit of 0.04 ppm for interaction in solution phase method. LPR showed an irreversible oxidation behavior at all investigated pH values on a bare PGE. Differential pulse adsorptive stripping (AdSDPV) voltammetric method was developed for the determination of LPR. Under these conditions, the current showed a linear dependence with concentration within a range of 0.005-0.20 ppm with a detection limit of 0.0014 ppm. Each determination method was fully validated and applied for the analysis of LPR in its pharmaceutical dosage form.     

A Genosensor for Sickle Cell Anemia Trait Determination

Sickle cell anemia (SCA) is a common recessive genetic condition in which patients produce an abnormal form of hemoglobin. The disease is common mainly among African individuals and in parts of the continent up to 40 % of the population presents its genetic trait. Currently, disease diagnosis and trait determination are performed using polymerase chain reaction, liquid chromatography and electrophoresis. Although these methods present high sensitivity and are well established, they are costly and require specialized equipment to be performed. We developed an electrochemical genosensor for simple and low cost SCA trait determination. The device was based on the immobilization of single DNA strands containing the disease related mutation on gold platforms using the self‐assembled monolayers technique. The determination of SCA trait was then performed using electrochemical impedance spectroscopy. The genosensor displayed a wide linear range (0.01 to 7.5 μmol L⁻¹, R²=0.979), with a detection limit of 7.0 nmol L⁻¹. Furthermore, the device was able to distinguish between DNA sequences containing or not the mutation (target and non‐target sequences) with precision and great reproducibility (10.4 %, n=3). It is expected that such sensor increases the number of SCA trait determination, promoting early diagnosis and genetically counseling.     

Mechanical evaluation of polymeric filaments and their corresponding 3D printed samples

3D printing technologies permits to produce functional parts with complex geometries, optimized topologies or enhanced internal structures. The relationship between mechanical performance and manufacturing parameters should be exhaustively analyzed to warrant the long term success of printed products. In this work, the mechanical performance of filaments based on acrylonitrile butadiene styrene (ABS), polylactic acid (PLA) and polylactic acid/polyhydroxyalkanoate (PLA/PHA) was investigated and also compared with their corresponding 3D printed samples. In general, the specimen dimensional deviations were found to be within the tolerances defined by the standard testing protocols. Density values revealed a high level of filament fusion promoting a nearly solid internal structure. The filaments exhibited improved tensile performance with respect to their corresponding printed samples. Tensile and bending performance looked quite independent of the raster angle. Izod impact behavior was increased, for ABS systems printed with the ±45° raster orientation. Quasi-static fracture tests displayed improved crack initiation resistance with the 0°/90° raster angle. The crack propagation observed for the ±45° specimens, through the bonding of the inter-layers, suggests weak entanglements.     

Advances in electrochemical detection for probing protein aggregation

Electrochemistry provides an array of methods to investigate protein aggregation and determine biomarkers of neurodenenerative diseases. Biosensors detecting monomeric or oligomeric biomarkers of Alzheimer's disease and Parkinson's disease evolved toward femtomolar, multiplexed detection in blood and biological fluids for less invasive diagnosis. The biosensors also serve as complementary tools in studies investigating putative biomarkers for the assessment of patient's cognitive decline. The study of protein aggregation via the direct electrochemical oxidation focused recently on enhanced sensitivity and on establishing correlations between protein structure and aggregation propensity. Departing from classic approaches, nanopore resistive pulse sensing and single-particle collision electrochemistry enable studying aggregates in solution. Growing applications converge toward accurate evaluation of aggregate populations and method adoption beyond proof of principle.     

3D打印便携式凝胶电泳装置用于蛋白质的快速检测

随着现场分析对于快速、便携和经济型检测的需求,分析仪器的便携化和微型化备受关注。3D打印技术的不断发展,将会极大推动小型化、便携式实验设备的开发和研制。分析仪器的微型化有助于促进资源不足地区在医疗现场、食品安全和环境污染等方面的现场监测。目前,用于蛋白质分离的凝胶电泳装置多为实验室用小型化分析仪器,可用于现场快速分离蛋白质的小型化仪器尚未见报道。该研究设计加工了一款便携式凝胶电泳装置,用于蛋白质的快速分离检测。首先,通过3D打印加工的凝胶电泳装置可在实验室内方便、快捷、低成本的复制。其次,通过对预染蛋白质相对分子质量标准的分离测试,对该系统结构进行优化。优化后该凝胶电泳装置电泳槽的尺寸仅为15 mm×20 mm×17 mm,采用3D打印技术可在5 h内加工完成,耗费打印材料10 mL。正负极所用电泳缓冲液共需4 mL,所使用的25 V锂电池可实现100 h左右的工作时间。装置优化后可实现蛋白质的快速高效分离。随后,在5种常用蛋白质相对分子质量标准的分离中,该装置与商业化平板凝胶电泳分离效果相当,同时具备更快的分离速度。该研究在便携式凝胶电泳装置的开发及其在蛋白质快速分离方面取得了初步成...