Large-Volume Self-Powered Disposable Microfluidics by the Integration of Modular Polymer Micropumps with Plastic Microfluidic Cartridges

Double-Sided Tape in Microfluidics: A Cost-Effective Method in Device Fabrication

The demand for easy-to-use, affordable, accessible, and reliable technology is increasing in biological, chemical, and medical research. Microfluidic devices have the potential to meet these standards by offering cost-effective, highly sensitive, and highly specific diagnostic tests with rapid performance and minimal sample volumes. Traditional microfluidic device fabrication methods, such as photolithography and soft lithography, are time-consuming and require specialized equipment and expertise, making them costly and less accessible to researchers and clinicians and limiting the applicability and potential of microfluidic devices. To address this, researchers have turned to using new low-cost materials, such as double-sided tape for microfluidic device fabrication, which offers simple and low-cost processes. The innovation of low-cost and easy-to-make microfluidic devices improves the potential for more devices to be transitioned from laboratories to commercialized products found in stores, offices, and homes. This review serves as a comprehensive summary of the growing interest in and use of double-sided tape-based microfluidic devices in the last 20 years. It discusses the advantages of using double-sided tape, the fabrication techniques used to create and bond microfluidic devices, and the limitations of this approach in certain applications.

High-Resolution 3D Printing Fabrication of a Microfluidic Platform for Blood Plasma Separation

Additive manufacturing technology is an emerging method for rapid prototyping, which enables the creation of complex geometries by one-step fabrication processes through a layer-by-layer approach. The simplified fabrication achieved with this methodology opens the way towards a more efficient industrial production, with applications in a great number of fields such as biomedical devices. In biomedicine, blood is the gold-standard biofluid for clinical analysis. However, blood cells generate analytical interferences in many test procedures; hence, it is important to separate plasma from blood cells before analytical testing of blood samples. In this research, a custom-made resin formulation combined with a high-resolution 3D printing methodology were used to achieve a methodology for the fast prototype optimization of an operative plasma separation modular device. Through an iterative process, 17 different prototypes were designed and fabricated with printing times ranging from 5 to 12 min. The final device was evaluated through colorimetric analysis, validating this fabrication approach for the qualitative assessment of plasma separation from whole blood. The 3D printing method used here demonstrates the great contribution that this microfluidic technology will bring to the plasma separation biomedical devices market.

Immuno-biosensor on a chip: a self-powered microfluidic-based electrochemical biosensing platform for point-of-care quantification of proteins

The realization of true point-of-care (PoC) systems profoundly relies on integrating the bioanalytical assays into "on-chip" fluid handing platforms, with autonomous performance, reproducible functionality, and capacity in scalable production. Specifically for electrochemical immuno-biosensing, the complexity of the procedure used for ultrasensitive protein detection using screen-printed biosensors necessitates a lab-centralized practice, hindering the path towards near-patient use. This work develops a self-powered microfluidic chip that automates the entire assay of electrochemical immuno-biosensing, enabling controlled and sequential delivery of the biofluid sample and the sensing reagents to the surface of the embedded electrochemical biosensor. Without any need for active fluid handling, this novel sample-to-result testing kit offers antibody-antigen immunoreaction within 15 min followed by the subsequent automatic washing, redox probe delivery, and electrochemical signal recording. The redox molecules ([Fe(CN)₆]^3-/4-) are pre-soaked and dried in fiber and embedded inside the chip. The dimensions of the fluidic design and the parameters of the electrochemical bioassay are optimized to warrant a consistent and reproducible performance of the autonomous sensing device. The uniform diffusion of the dried redox into the injected solution and its controlled delivery onto the biosensor are modeled via a two-phase flow computational fluid dynamics simulation, determining the suitable time for electrochemical signal measurement from the biosensor. The microfluidic chip performs well with both water-based fluids and human plasma with the optimized sample volume to offer a proof-of-concept ultrasensitive biosensing of SARS-CoV-2 nucleocapsid proteins spiked in phosphate buffer saline within 15 min. The on-chip N-protein biosensing demonstrates a linear detection range of 10 to 1000 pg mL^-1 with a limit of detection of 3.1 pg mL^-1. This is the first self-powered microfluidic-integrated electrochemical immuno-biosensor that promises quantitative and ultrasensitive PoC biosensing. Once it is modified for its design and dimensions, it can be further used for autonomous detection of one or multiple proteins in diverse biofluid samples.