The authors have declared that no competing interests exist.
The centrifuge is an essential tool for many aspects of research and medical diagnostics. However, conventional centrifuges are often inaccessible outside of standard laboratory settings, such as remote field sites, because they require a constant external power source and can be prohibitively costly in resource-limited settings and Science, technology, engineering, and mathematics (STEM)-focused programs. Here we present the 3D-Fuge, a 3D-printed hand-powered centrifuge, as a novel alternative to standard benchtop centrifuges. Based on the design principles of a paper-based centrifuge, this 3D-printed instrument increases the volume capacity to 2 mL and can reach hand-powered centrifugation speeds up to 6,000 rpm. The 3D-Fuge devices presented here are capable of centrifugation of a wide variety of different solutions such as spinning down samples for biomarker applications and performing nucleotide extractions as part of a portable molecular lab setup. We introduce the design and proof-of-principle trials that demonstrate the utility of low-cost 3D-printed centrifuges for use in remote field biology and educational settings.
This Community Page article describes a low-cost 3D-printed centrifuge to enable sequencing in remote field conditions and lowering the barrier to synthetic biology research in high schools to broaden participation in hands-on STEM.
The centrifuge is an indispensable piece of equipment for laboratories, with general applications ranging from DNA isolation to clinical diagnostics. Yet, conventional centrifuges are often inaccessible outside of established lab settings (such as remote field sites), require a constant external power source, and can be prohibitively costly for STEM-focused programs. Progress has been made in the field of frugal science [
Here, we present the 3D-Fuge, a 3D-printed device based on the principles of the paperfuge [
(A) Example of the 3D-Fuge utilized for Case Study 2, with 0.2 mL PCR tubes (VWR, USA) placed alongside for comparison. (B) Construction of the 3D-Fuge through 3D Printing. (C) 3D-Fuge utilized in Case Study 1 (rainforest in Peru), shown holding up to 4 spin-columns and flow-through tubes for nucleotide extractions. (D) Example usage of the 3D-Fuge in the field located in Southeastern Peru. (E) Comparison of long-range PCR results from human cheek swab nucleotide extractions using a standard benchtop centrifuge (left) and the 3D-Fuge (right). (F) Image of the portable lab setup, including the 3D-Fuge, the miniPCR (miniPCR) powered by an external battery pack, the MinION DNA sequencer (Oxford Nanopore Technologies, USA), and the Foldscope (Foldscope Instruments, USA). (G) Image of the 3D-Fuge utilized in Case Study 2 (high school in Atlanta, Georgia) shown holding PCR tubes (0.2 mL). (H) Usage of the 3D-Fuge in a high school. (I) Image of color output processing for data collection of chromoprotein expression. Phone captures the image of liquid culture pellets for RGB color analysis. (J) Sample illumination chamber utilized for standardized sample illumination. (K–L) Representative time evolution of the RPM and RCF of the 3D-Fuges over 2 cycles (counterclockwise and then clockwise inversion) utilized in each of the case studies. The peak RPM achieved is approximately 6,000 for both case studies. The above graphs illustrate the overall oscillatory motion of the 3D-Fuge, the change in angular velocity demonstrating the peak RPM over an interval, and the changing relative centrifugal force with a relative maximum of 2100
The total cost was calculated by combining the cost of the string used and 3D-printing material (see
3D-Fuge Model | String Length (m) | Weight (grams) | Radius (mm) | Volume (mL) | RCF (× |
Cost |
---|---|---|---|---|---|---|
Design 1 | 0.46–0.56 | 26.30 | 30 | 2.0 | 1,370 | $0.72–$0.74 |
Design 2 | 1.04 | 13.50 | 45 | 0.2 | 2,070 | $0.41 |
To demonstrate the capability of this device to perform routine experiments without access to conventional laboratory equipment, we carried out nucleotide extractions under both lab and remote field conditions (
Nucleotide extractions are a necessary first step for numerous molecular experiments, such as DNA sequencing projects, and often require centrifugation steps to separate and purify high-quality nucleic acids from the sample of interest. The ability to rapidly extract and purify nucleic acids with a low-cost hand-powered centrifuge can be useful for a wide range of molecular applications when one does not have access to conventional laboratory equipment, such as in the field or in resource-limited settings. Portable sequencing projects are already emerging in applied field settings, including real-time species or environmental sample identifications [
(A, B) Field site for the portable lab study located in Tamboapta, Peru. (C–F) Examples of specimens collected for
Before the expedition, we first compared DNA extractions in the lab using a standard benchtop centrifuge (Eppendorf, model 5415 D) and the hand-powered 3D-Fuge. A human cheek swab sample was collected and DNA extractions were carried out using the Quick-DNA Miniprep Plus Kit (Zymo Research, Irvine, CA) according to manufacturer's protocol. Eluted DNA yields were assessed using a Nanodrop, and the results between centrifuge strategies, such as nucleotide concentration and a 260/280 ratio, were comparable (
Next, while in the Peruvian Amazon, specimens such as whole insects and plant leaves were collected and preserved in 1.5 mL Eppendorf tubes containing DNA Shield (Zymo) for downstream processing (
As before, all DNA extractions in the field were carried out using the Quick-DNA Miniprep Plus Kit (Zymo). Specimens were homogenized using a pestle and incubated with proteinase K for 1 to 3 hours (
For the butterfly (
Reporter proteins are a quintessential part of synthetic biology [
(A) Location of high school on map of the United States. (B) Workflow schematic for color analysis, beginning with transformation of the plasmid and plating, growth of liquid cultures, isolation of small portion of culture, centrifugation with 3D-Fuge, and sample illumination chamber and color picker for measurements. (C) Images of 3D-Fuges utilized in experiments. (D) Image of sample illumination chamber and phone used for capturing the image (Left). Image of view of chromoprotein-expressing bacterial pellets in sample illumination chamber (Right). This image does not represent the pellets utilized for measurements indicated in Fig 3G. (E) Diagram for regulation of chromoprotein expression in plasmid construct. (F) Color wheel utilized for hue value measurements. As darker shades occur counterclockwise around the color wheel, darker colors correlate with a smaller hue value. (G) Hue value measurements for Scrooge Orange chromoprotein at varying IPTG concentrations. As expected, increasing IPTG concentrations results in smaller hue values, indicating successful analysis of color expression using the 3D-Fuge and sample illumination chamber. SD,
The Isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible chromoprotein plasmid constructs (obtained from ATUM Bio, 2018;
The chamber was utilized to ensure standardized white illumination of the sample and facilitate the capturing of an image through the opening at the top (
Developments in portable nucleotide sequencing hold great promise for fields such as human health applications, metagenomics, agriculture, and molecular taxonomy [
One limitation to the current 3D-Fuge design is that it can hold up to 4 spin-column tubes at once, which means increasing radius and weight to accommodate additional tubes may reduce the maximum speed and increase muscle fatigue by the user [
The field of frugal science is helping to develop new low-cost portable tools and applications, such as the ability to perform real-time diagnostics in remote environments, and enabling greater access to those with an interest in scientific devices, such as high school students. Here we introduce the 3D-Fuge, a 3D-printed device capable of centrifugation of a wide variety and volumes of solutions, such as spinning down samples for biomarker applications and performing nucleotide extractions as part of a portable molecular lab setup. Overall, we hope that the design and proof-of-principle trials presented here will stimulate others to continue research into the development of low-cost scientific devices and that the 3D-Fuge will be valuable to a range of users including students, labs in resource limited settings, and field researchers.
Shows the RPM of both designs over a cycle of 5 runs. Both designs have similar peak RPM at around 6,000; however, they have slightly different periods of revolution. The data shows reproducible rpm cycles with time. Data for the graph can be found on GitHub (
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Shows the RCF values of both designs over a cycle of 5 runs. Although both the designs have the same rpm values, Design 1 has a smaller g-force due to its smaller radius (see
(TIF)
(A) Components and 3D-printed parts of the 3D-Fuge. (B) Comparison of human cheek swab DNA extractions using a conventional laboratory bench top centrifuge (left) and the 3D-Fuge (right) with their respective Nanodrop DNA quantifications. Long-range mitochondrial PCR products using these extracts can be found in
(TIF)
(A) Bird's eye view of the main piece for the 3D-Fuge including its dimensions. (B) Bottom-up view of the 3D-Fuge as well as its dimensions. (C) Connector piece(s) dimensions. CAD, Computer-aided design.
(TIF)
(A) Top-down view of the 3D-Fuge and its dimensions. (B) Bottom-up view of the 3D-Fuge and its dimensions. (C) Bird's eye view of the 3D-Fuge including its dimensions. CAD, Computer-aided design.
(TIF)
Detailed protocols for chromoproteins transformation, 3D-Fuge design and materials, nucleotide extractions, and high-speed video analysis to estimate spinning speed of 3D-Fuges.
(PDF)
A. F. P. would like to thank staff at the Jacobs Institute for Design Innovation as well as members of the Patel Lab, Rainforest Expeditions, Helen Kurkjian, Bjorn Hartmann, and the Center for Interdisciplinary Biological Inspiration in Education and Research (CiBER) at the University of California Berkeley for feedback and helpful suggestions on the project. We would also like to thank E. Kim and C. Lee for assisting with centrifugation of chromoprotein samples, and the rest of the 2018 Lambert iGEM Team and BhamlaLab for their support and feedback.
Collection permits in Peru were issued by the Servicio Nacional Forestal y de Fauna Silvestre, 403-2016-SERFORDGGSPFFS, 019-2017-SERFOR-DGGSPFFS.
Basic Local Alignment Search Tool
Hue-Saturation-Luminance
National Center for Biotechnology Information
Polymerase chain reaction
polymeric material
relative centrifugal force
revolutions per minute
ribosomal DNA
Red-Green-Blue
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