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3D Printing Techniques in Environmental Science and Engineering Will Bring New Innovation Ligang Hu and Guibin Jiang* State Key Laboratory of Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China printing. The research areas described below are examples of areas that will likely benefit from 3D printing in the near future. (1) 3D printing of miniaturized devices for on site environmental assessment or rapid toxicity evaluation of specific chemicals and accurate evaluation of their potential human impact. For example, a pilot study has demonstrated a small-scale single chamber air-cathode microbial fuel cell fabricated via 3D printing for continuous water quality monitoring. This could act as a sensor for chemical oxygen demand or detect the content of cadmium in water.3 Lab-on-a-Chip systems can be readily fabricated via 3D printing nowadays and have been widely applied in various types of toxicity assays, including applications in environmental studies. Given the low cost and accessibility, it could be expected that 3D-printed Lab-on-a-Chip systems will be widely applied in environmentally relevant toxicity assays, although current application remains rare. 3D printing technology will not change the theory behind these miniaturized devices, but will provide a pathway to precisely and cost-effectively fabricate them on site. This practice will enable the performance of environmental 3D printing techniques are currently driving innovation in the assessment or toxicity assays rapidly in rural locations manufacturing industry, and this innovation will likely extend to without the need for expensive instrumentation and may all areas of science and technology in the near future. 3D substantially change the way for environmental monitorprinting enables the digital design and fabrication of complex ing and toxicity assay in undeveloped areas. 3D objects, layer-by-layer, with a wide range of materials. The (2) 3D bioprinting of organs with various cell types and technique has several advantages over traditional manufacturing mimicking of the function of real organs. This is the most advanced research front of 3D printing in the life processes, such as the ability to perform rapid prototyping, sciences. Toxicity assays based on 3D bioprinted organs allowing minor variations on a basic design, and the fabrication may serve as alternatives for classical toxicity assays using of unique objects. For example, dentists can now use 3D animal models. The benefits of such assays have been printing to produce precise dental implants within hours to demonstrated in some areas. For example, synthetic skin exactly match the needs of a specific patient; such a process has been fabricated through the 3D bioprinting of stem generally takes weeks with traditional fabrication. cells to test the safety, effectiveness, and appearance of In past few years, the rate of research publications involving cosmetic products “in vivo”.4 The fabrication process was 3D printing has increased considerably. For example, the relatively fast and was able to simulate different types of number of publications in Web of Science found using “3D skin, in which multiple types are not readily provided for printing” or “additive manufacture” as search terms has traditional model. Furthermore, considering the discrepincreased by thousands annually since 2013, exceeding a total ancies between the effects of chemicals on human and of 10 000 in 2016. Nevertheless, in the field of environmental animal models, 3D bioprinted organs with human stem science and engineering, the application of 3D printing cells may provide more “real” data for evaluation of technology remains rare. A limited number of studies have chemical safety on humans. been performed, and those available have mainly focused on the (3) Manufacturing of devices with a sophisticated geometry, which could be used for treatment or purification of fabrication of small devices, such as atmospheric sampling water, collection of samples, measurement of pollutants, devices for fine particles or devices for water treatment, or on the potential environmental and health concerns originating from 3D printing.1,2 Thus, environmental science and Received: January 16, 2017 engineering still has a significant potential to benefit from 3D © XXXX American Chemical Society
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DOI: 10.1021/acs.est.7b00302 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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Environmental Science & Technology
Figure 1. A gel electrophoresis cell for metalloprotein analysis fabricated via 3D printing. (A) Blueprint of the gel electrophoresis cell. (B) The fabricated gel electrophoresis cell was coupled to ICP-MS for metalloprotein analysis.
living cells. While, it is currently difficult to print a single object with multiple raw materials considering the different printer requirements. Additionally, commercially available printing materials remain limited. For example, polylactic acid, acrylonitrile butadiene styrene, and resins are the most commonly utilized materials in commercially available benchtop printers and the properties (i.e., mechanic properties and chemical/thermal resistance) of these materials limit their application in scientific research. Nevertheless, the current bottleneck hindering the large scale application of 3D printing in environmental science and engineering is a lack of awareness and development of pathways to integrate the technology into current research in the area.
or reaction apparatus (Figure 1). This is the most straightforward method to apply 3D printing in environmentally relevant research. For example, various types of membrane modules with a better performance for water treatment were designed and fabricated via 3D printing technology.5 Optimization of the performance of membrane modules is difficult given their complex module geometry and manufacturing constraints with traditional fabrication methods. The capability of 3D printing in readily manufacturing of objectives with sophisticated geometry enables this kind of optimization and speeds up the development of better performance membrane module. Nevertheless, currently available commercial 3D printers have a printing size limitation. For example, the size of the printed object is generally not larger than 30 cm in any dimension with most benchtop printers. To fabricate large and complicated devices, the printing of discrete elements and their subsequent assembly seems a promising approach.6 Although being considered to have beneficial environmental effects, recent studies have demonstrated that 3D printing may potentially impact the environment in multiple ways. For example, a large amount of fine particles as well as multiple hazardous volatile organic compounds are emitted in the process of printing,7 resulting in health concerns for the operator. Measurable adverse effects on zebrafish embryos were observed when exposed to 3D-printed parts,2 implying a potential aquatic toxicities if the printed objects largely release to environment. It is also noteworthy that the efficiency of manufacturing with 3D printing (energy demand and material waste) depends on how the machines work. Further investigations leading to an optimized procedure for 3D printing are therefore needed to lower the environmental impact and achieve sustainable production and consumption of the technique and 3D printed products.8 As a largely unexplored area, the application of 3D printing in environmental science and engineering may substantially advance or even reshape the field. The performance and accessibility of current machines (i.e., the printing resolution and type of raw materials used) still limit their large scale application in this area, especially with regards to commercially available benchtop printers. The most common materials currently employed in 3D printings include plastics, metals, and
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AUTHOR INFORMATION
Corresponding Author
*Phone: +86 (10) 62849129; e-mail:
[email protected]. ORCID
Ligang Hu: 0000-0002-6213-4720 Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Oskui, S. M.; Diamante, G.; Liao, C.; Shi, W.; Gan, J.; Schlenk, D.; Grover, W. H. Assessing and Reducing the Toxicity of 3D-Printed Parts. Environ. Sci. Technol. Lett. 2016, 3, 1−6. (2) Staymates, M.; Bottiger, J.; Schepers, D.; Staymates, J. A Streamlined, High-Volume Particle Impactor for Trace Chemical Analysis. Aerosol Sci. Technol. 2013, 47, 945−954. (3) Di Lorenzo, M.; Thomson, A. R.; Schneider, K.; Cameron, P. J.; Ieropoulos, I. A Small-Scale Air-Cathode Microbial Fuel Cell for Online Monitoring of Water Quality. Biosens. Bioelectron. 2014, 62, 182− 188. (4) Ng, W. L.; Wang, S.; Yeong, W. Y.; Naing, M. W. Skin Bioprinting: Impending Reality or Fantasy? Trends Biotechnol. 2016, 34, 689−699. (5) Low, Z.-X.; Chua, Y. T.; Ray, B. M.; Mattia, D.; Metcalfe, I. S.; Patterson, D. A. Perspective on 3D Printing of Separation Membranes and Comparison to Related Unconventional Fabrication Techniques. J. Membr. Sci. 2017, 523, 596−613. (6) Bhargava, K. C.; Thompson, B.; Malmstadt, N. Discrete Elements for 3D Microfluidics. Proc. Natl. Acad. Sci. U. S. A. 2014, 111, 15013− 15018.
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DOI: 10.1021/acs.est.7b00302 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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Environmental Science & Technology (7) Kim, Y.; Yoon, C.; Ham, S.; Park, J.; Kim, S.; Kwon, O.; Tsai, P. Emissions of Nanoparticles and Gaseous Material from 3D Printer Operation. Environ. Sci. Technol. 2015, 49, 12044−12053. (8) Rejeski, D., Huang, Y., An NSF Workshop Report: Environmental Implications of Additive Manufacturing; The Science and Technology Innovation Program of the Woodrow Wilson International Center for Scholars: Washington, DC, 2015; https://www.wilsoncenter.org/ sites/default/files/nsf_am_env_final_red.pdf.
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DOI: 10.1021/acs.est.7b00302 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
