In recent years, efforts in the development of lab-on-a-chip (LoC) devices for point-of-care (PoC) applications have increased to bring affordable, portable, and sensitive diagnostics to the patients’ bedside. To reach this goal, research has shifted from using traditional microfabrication methods to more versatile, rapid, and low-cost options. This work focuses on the benchtop fabrication of a highly sensitive, fully transparent, and flexible poly (dimethylsiloxane) (PDMS) microfluidic (μF) electrochemical cell sensor. The μF device encapsulates 3D structured gold and platinum electrodes, fabricated using a shape-memory polymer shrinking method, which are used to set up an on-chip electrochemical cell. The PDMS to PDMS-structured electrode bonding protocol to fabricate the μF chip was optimized and found to have sufficient bond strength to withstand up to 100 mL/min flow rates. The sensing capabilities of the on-chip electrochemical cell were demonstrated by using cyclic voltammetry to monitor the adhesion of murine 3T3 fibroblasts in the presence of a redox reporter. The charge transfer across the working electrode was reduced upon cell adhesion, which was used as the detection mechanism, and allowed the detection of as few as 24 cells. The effective utilization of simple and low cost bench-top fabrication methods could accelerate the prototyping and development of LoC technologies and bring PoC diagnostics and personalized medicine to the patients’ bedside.
Macrophages are major contributors to the rejection of foreign materials introduced to living tissues. Given that cell‐surface interactions can have important effects on phagocytic capacity and cytokine production, changes in macrophage morphology have been reported for different materials and surface patterns. However, the details of how surface topography impacts morphology and function remain unclear. This study investigates whether changes in the surface topography of glassy substrates alter macrophage shape and modulate phagocytic function and the secretion of pro‐inflammatory cytokine IL‐6. The morphology of murine bone marrow–derived macrophages cultured on micro‐ and nanostructured SiO2 films is quantified through fractal analysis. It is observed that membrane protrusions increase on nanostructured surfaces and macrophages adopt unique star‐shaped morphologies on microstructures. Macrophages on both micro‐ and nanostructured surfaces display greater phagocytic capacity, compared to those on flat controls. In contrast, the secretion of pro‐inflammatory cytokine IL‐6 is not increased when cells are cultured on the structured surfaces. The diffusion of a transmembrane receptor is also measured, which reveals no impact of structuring or plasma treatment on receptor diffusion. Altogether, these data indicate that surface topography does not increase IL‐6 production or alter membrane mobility but can significantly impact phagocytosis.
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