Low-Cost 3D-Printed Microfluidic Devices for Rapid Prototyping and Biological Applications

Summary

We have developed a low-cost, 3D-printed microfluidic device and an open-source Python-based software that can generate programmable concentration gradients. We have validated this customizable platform using osmometry and colorimetric analysis, enabling reproducible osmotic exposure studies and biomedical assays with materials costing under $5 and consumer-grade 3D printing.

Abstract

Microfluidic devices offer precise control over solution mixing and gradient generation, essential for cell-based assays in cryobiology and biomedical research. However, traditional fabrication methods are time-consuming, costly, and require specialized expertise, which limits accessibility. To address these challenges, we developed a cost-effective, reliable, and fully 3D-printed microfluidic device workflow to facilitate rapid and inexpensive prototyping using a consumer-grade printer and biocompatible plastic resins. Here, we demonstrate this workflow with a fluidic mixing device capable of generating programmable concentration gradients and solution combinations. Commercial mixing devices cost more than $300 each and cannot be customized. By utilizing affordable resin materials and an innovative open-channel design sealed with transparent adhesive tape, we overcame common fabrication issues such as channel clogging, enabling rapid and reproducible fabrication of complex microfluidic architectures, all at a materials cost of less than $5. Here we demonstrate this workflow, integrating dual-syringe pumps to create linear osmotic gradients, ranging from iso-osmotic (~300 mOsm/kg) to hyperosmotic (~9,000 mOsm/kg) conditions, followed by a return to isotonicity over defined intervals. To ensure automation and reproducibility, we developed an open-source Python-based software tool that precisely regulates syringe pump activation, flow rates, and gradient timing. The device's performance was validated through continuous osmometric measurements, which confirmed both the linearity and accuracy of gradient generation, and colorimetric measurements to confirm mixing efficacy. This accessible and cost-effective microfluidic platform significantly improves the reproducibility of osmotic exposure studies and shows potential for various biomedical applications, including drug screening and precise chemical modulation.

Introduction

Microfluidic devices have become essential for controlling concentrations and chemical environments in cell-based assays, osmotic stress studies, and drug administration experiments in biomedical research, cryobiology, and other diagnostic applications^1,2. These devices allow for the precise control of fluid flow and concentration at the micrometer scale. For instance, microfluidic devices have been used for the addition and removal of cryoprotective agents during the cryopreservation of cells to prevent osmotic damage³. Similarly, these microfluidic devices are also used to establish s....

Protocol

1. Designing the microfluidic mixing slide

1. Using a suitable CAD software (e.g., AutoCAD 3D or TinkerCAD, AutoDesk, Inc), design a serpentine microchannel with two-channel inlets and a mixing Y-shaped junction, followed by a pathway to facilitate effective mixing and provide adequate channel length for diffusion. Combine the channel elements into a single region.
2. Create a rectangular slide (85 mm x 28 mm x 3 mm) to serve as the base substrate. Then, subtract the previously designed serpentine microchannel from the top surface of the slide to form an open channel structure with proper depth and width.
3. Create each threaded connector port (....

Results

Figure 1 illustrates the overall setup of our device

Figure 1: System setup.From left to right, Python-based control software allows the creation of precise time vs concentration curves by vary.......

Discussion

Microfluidics mixing chambers are typically expensive components manufactured with pre-set configurations. This manuscript demonstrates how rapid prototyping and custom code enable laboratories to rapidly develop mixing chambers, facilitating a wide variety of experimental setups.

We validate complete mixing using colorimetric analysis and osmometry. The osmotic measurements were further compared to calculated theoretical values based on mixture concentration. Colorimetric analysis and osomome.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1/16” OD PEEK Capillary Tubing – 65 µm inner diameter	IDEX Health and Science, USA	SKU: ID-1560	1.5 m, cut into smaller sections. Purchased from Darwin Microfluidics
3D Printer UV Resin Curing Light – 230 V 405 nm	Skouphy, China		Used as post curing station, by placing it in a white styrafoam box with resin part for ~6 S
3x Gastight 1/4-28 UNF Glass Syringes – 5 mL	Hamilton, USA	SKU: HM-10103664	1/4-28 fitting allows for connection to 1/16” PEEK Tubing. Purchased from Darwin Microfluidics
Dimethyl Sulfoxide (DMSO), Certified ACS	Fisher Scientific, USA	Cat.No: D128-1	Purchased from Fisher Scientific
ELITechGroup CALIBRATION STANDARD, 850 MOSM/K	ELITechGroup, USA	VCAT: SS-277, Cat. No: NC1876875	Purchased from Fisher Scientific
ELITechGroup CALIBRATION STANDARD, 300 MOSM/K	ELITechGroup, USA	VCAT: SS-276, Cat. No: NC1876872	Purchased from Fisher Scientific
Flangeless PFA Fittings & ETFE Ferrules 1/4”-28 to 1/16”	IDEX Health and Science, USA	SKU: ID-XP-245X	10 pack, Purchased from Darwin Microfluidics
Food Colouring	Club House, Canada
FreezePoint 6000P Freezing Point Osmometer	ELITechGroup, USA	Model: 6000P
FreezePoint Measuring Vessels	ELITechGroup, USA	VCAT: SS-279, Cat. No: NC1876881	Purchased from Fisher Scientific
Gorilla Super Glue Gel	The Gorilla Glue Company, USA	https://gorillatough.com/product/gorilla-super-glue-gel/
Herringbone Mixer - Glass Chip	Little Things Factory	SKU: LTF-012.00-4264	Purchased from Darwin Microfluidics
Hyperosmotic Media - 40% DMSO (v/v) with 1.2 M NaCl			Made in Lab
Ibidi µ-Slide VI 0.4 – ibiTreat	Ibidi, Germany	Cat.No: 80606
Isosmotic Media- Cytiva HyClone Phosphate Buffered Saline (PBS)	Cytiva, USA	Cat.No: SH3025601	Purchased from Fisher Scientific
Motic Stereoscope	Motic, Hong Kong	Model:  SMZ-168 TLED
NE1000 SyringONE Syringe Pumps	New Era Pump Systems Inc., USA	Model: 1010-US	Purchased from New Era Pump Systems Inc.
Phrozen Sonic Mini 8k Resin 3D Printer	Phrozen Tech Co., LTD. Taiwan (R.O.C.)		Phrozen Sonic Mini 8k
Pump-to-PC RS-232 Primary Network Cable	New Era Pump Systems Inc., USA	Model: CBL-PC-PUMP-7 (7 ft. cable)	9-pin Serial to RS232 converter, Purchased from New Era Pump Systems Inc.
Pump-to-Pump Secondary Network Cable	New Era Pump Systems Inc., USA	Model: CBL-NET-7 (7 ft. cable)	RS232 cable, Purchased from New Era Pump Systems Inc.
Resin- PowerResins Sugical Guide Resin 1000 GR	PowerResins, 3BFab Inc, Türkiye	REF: PSG-03-C
RS-232 to USB Converter Cable	Prolific Technology, Taiwan (R.O.C.)	Model: CBL-USB232	Purchased from New Era Pump Systems Inc.
Slide Sealing Tape- Crystal Clear Gorilla Tape 1.88” x 9 yards	The Gorilla Glue Company, USA
Sodium Chloride (NaCl)	EMD Millipore, MilliporeSigma, Germany	Cat. No: M1064041000	Purchased from Fisher Scientific