On-Chip Open Microfluidic Devices for Chemotaxis Studies

Abstract

Microfluidic devices can provide unique control over both the chemoattractant gradient and the migration environment of the cells. Our work incorporates laser-machined micro and nanofluidic channels into bulk fused silica and cover slip-sized silica wafers. We have designed “open” chemotaxis devices that produce passive chemoattractant gradients without an external micropipette system. Since the migration area is unobstructed, cells can be easily loaded and strategically placed into the devices with a standard micropipette. The reusable monolithic glass devices have integral ports that can generate multiple gradients in a single experiment. We also used cover slip microfluidics for chemotaxis assays. Passive gradients elicited from these cover slips could be readily adapted for high throughput chemotaxis assays. We have also demonstrated for the first time that cells can be recruited into cover slip ports eliciting passive chemoattractant gradients. This proves, in principle, that intravital cover slip configurations could deliver controlled amounts of drugs, chemicals, or pathogens as well as recruit cells for proteomic or histological analysis in living animals while under microscopic observation. Intravital cover slip fluidics will create a new paradigm for in vivo observation of biological processes.

Lymphocytes can self-steer passively with wind vane uropods

“…For instance, polarized cells are commonly described as being more sensitive to chemoattractant at the anterior than at the posterior 5 . Recent microfluidics experiments on neutrophil chemotaxis show indeed that a cell engages a turn when its leading edge only is exposed to a 90°change of chemical cue direction 12 . Similarly, we used a microfluidic chamber to expose lymphocytes to a 90°c hange in flow direction (Fig.…”

A Novel Microdevice for Rapid Neutrophil Purification and Phenotyping in Type 2 Diabetes Mellitus

“…The developed microfluidic chemotaxis assay characterizes neutrophil migration and motility (velocity), which can yield useful clinical information in patients with burn injury and asthma . Unlike analysis of single‐cell trajectories which is limited by the field‐of‐view during imaging, the measured chemotaxis phenotypes are based on average or “bulk” neutrophil migratory behavior which do not require expensive microscopy system for time‐lapse imaging, and offers the potential for performing multiple chemotaxis assays each time.…”

Intravital Microfluidic Windows for Delivery of Chemicals, Drugs and Probes

“…Channels were fabricated using a laser ablation system which consists of a diode-pumped frequency doubled Neodymium-doped Yttrium Orthovanadate (Nd:YVO4) laser pump (Verdi), a Ti:Sapphire laser oscillator (Tsunami) and a regenerative amplifier (RegA9000). The substrate position was controlled by an Aerotech ANT95 nanopositioning system and is capable of carefully coordinating the alignment and positioning of the design features through software-controlled stages with nanometer precision.We have previously shown that we can make several chemotaxis devices in glass coverslips [5]. Here, we demonstrate the usefulness of intravital microfluidic windows by staining subcellular organelles in tissues, obtaining cellular responses by adding ligands, and have also set up chemical gradients, all in a living animal.…”