In biomedical studies, wearable sensors are used to analyze the patient’s physiological parameters. 3D printing can improve the manufacturing of biosensors since its techniques rely on adding the desired material layer-by-layer by a simple one-step digitally controlled process, avoiding some disadvantages associated with screen printing, such as masking and drying steps. Besides, 3D printing methodologies require fewer steps and less manual labor to complete the prototypes compared to conventional methods: once the prototype is designed and uploaded to the system, the biosensor will be manufactured accordingly, eliminating the need for much human intervention. 1 2
At Washington State University's School of Mechanical and Materials Engineering, researchers have developed a new approach to printing glucose biosensors. Commercial carbon ink modified with Prussian blue as an electron transfer mediator and a custom enzyme ink were 3D printed onto a tattoo paper using the direct-ink-writing method. The results show that 3D printed electrodes have a more uniform and defect-free surface, making them more sensitive to electrochemical detection. Furthermore, the direct-ink-writing method has been shown to save time and material, reducing the overall course of the operation, compared to other methods. 3 4
Figure 1: The biosensor manufacturing process developed by Washington State University 4
Several mobile phone-assisted diagnostics have been developed to lower the cost of current diagnostic strategies to support 3D printed equipment and improve the performance of existing diagnostics like spectrophotometers and Polymerase Chain Reaction (PCR). Similarly, research by Plevniak et al. (2016) created a disease diagnosis 3D-printed equipment that detects blood hemoglobin levels by integrating 3D printing of microfluidic point-of-care device with smartphone-based technology. The smartphone promotes colorimetric signal detection to overcome the distance barrier for efficient screening. The device mechanism works by analyzing a finger prick of blood driven by capillary force into the mixing chamber, mixed with an oxidizing agent. 5 6
A transparent resin consisting of triethylene glycol diacrylate, sobornyl methacrylate, and phenylbis(2,4,6-trimethylbenzoyl)-phosphine 2% -3% phosphine oxide photoinitiator was used to produce clear 3D microfluidic chips. Thus, even though this study focuses on the point-of-care diagnosis of anemia, it can be adapted to enable the development of other blood-based diagnostic tests, representing a novel and efficient diagnostic model. 6
Figure 2: Low-cost, smartphone-based, 3D-printed POC microfluidic chip (smartphone iPOC3D system) for rapid diagnosis of anemia in 60 sec. 6
REFERENCES
1. Muñoz, J. & Pumera, M. 3D-printed biosensors for electrochemical and optical applications. Trends Analyt. Chem. 128, 115933 (2020).
2. Han, T., Kundu, S., Nag, A. & Xu, Y. 3D Printed Sensors for Biomedical Applications: A Review. Sensors 19, (2019).
3. Nesaei, S. et al. Micro additive manufacturing of glucose biosensors: A feasibility study. Anal. Chim. Acta 1043, 142–149 (2018).
4. 3D-printed biosensors for diabetes patients. https://www.labnews.co.uk/article/2024966/3d_printed_biosensors_for_diabetes_patients.
5. Sharafeldin, M., Jones, A. & Rusling, J. F. 3D-Printed Biosensor Arrays for Medical Diagnostics. Micromachines (Basel) 9, (2018).
6. Plevniak, K., Campbell, M., Myers, T., Hodges, A. & He, M. 3D printed auto-mixing chip enables rapid smartphone diagnosis of anemia. Biomicrofluidics 10, 054113 (2016).