An automated optofluidic biosensor platform combining interferometric sensors and injection moulded microfluidics

Abstract

A primary limitation preventing practical implementation of photonic biosensors within point-of-care platforms is their integration with fluidic automation subsystems. For most diagnostic applications, photonic biosensors require complex fluid handling protocols; this is especially prominent in the case of competitive immunoassays, commonly used for detection of low-concentration, low-molecular weight biomarkers. For this reason, complex automated microfluidic systems are needed to realise the full point-of-care potential of photonic biosensors. To fulfil this requirement, we propose an on-chip valve-based microfluidic automation module, capable of automating such complex fluid handling. This module is realised through application of a PDMS injection moulding fabrication technique, recently described in our previous work, which enables practical fabrication of normally closed pneumatically actuated elastomeric valves. In this work, these valves are configured to achieve multiplexed reagent addressing for an on-chip diaphragm pump, providing the sample and reagent processing capabilities required for automation of cyclic competitive immunoassays. Application of this technique simplifies fabrication and introduces the potential for mass production, bringing point-of-care integration of complex automated microfluidics into the realm of practicality. This module is integrated with a highly sensitive, label-free bimodal waveguide photonic biosensor, and is demonstrated in the context of a proof-of-concept biosensing assay, detecting the low-molecular weight antibiotic tetracycline.

A Review of Current Methods in Microfluidic Device Fabrication and Future Commercialization Prospects

“…Other research conducted by Szydzik et al aims to improve the functionality of injection molded microfluidics by introducing a novel method of integrating complex fluid handling into existing methods [32]. They argue that improved fluid handling in injection molded microfluidics will be required in order for this technique's full potential to be realized in point-of-care diagnostics.…”

Silicon‐Based Integrated Label‐Free Optofluidic Biosensors: Latest Advances and Roadmap

“…In 2017, Szydzik et al reported a multiplexed BiMW‐based biosensor chip integrated with pneumatic valve‐based microfluidic modules offering a high degree of flexible, automatic and on‐chip sequential manipulation of multiple fluidic samples. [ 192 ] As illustrated in Figure a,b, utilizing a one‐step injection molding technique, a thin PDMS slab‐based microfluidic channel was integrated with the silicon sensor chip and also a thick PDMS interface slab. An automatic competitive immunoassay was performed with “cycles” of reference and competitive assays for detecting tetracycline antibiotics.…”

A Review of Design Considerations for Hemocompatibility within Microfluidic Systems

“…On-chip microfluidic fluid handling technologies have been applied to highly complex applications, 7 including gene expression profiling, 208,209 polymerase chain reaction, 210 cell culture platforms 211,212 , single cell analysis, 184,213 and biosensor integration. 214,215 While complex microfluidic systems have been demonstrated with a high degree of sophistication within these areas of application, little evidence exists in the literature of development of these high throughput systems with a specific focus on manipulation of whole blood. While it is possible that this delayed application is due to fabrication impracticalities, 216 challenges associated with hemocompatibility could also play a role, and it is possible that achieving the full potential that complex on-chip microfluidic systems have demonstrated in other application areas may be dependent on careful consideration of material and operational hemocompatibility.…”