Fabrication and characterization of a microfluidic flow cytometer for the advanced undergraduate laboratory
Bibliographic record
Abstract
Microfluidic devices can be used to explore a vast range of phenomena in biophysics and soft-matter physics. While the popularity of these devices is in part driven by the ease of soft-lithography, most research labs still depend upon expensive, clean-room fabrication of photoresist molds, which can make this technique inaccessible to the undergraduate laboratory. However, there are much simpler, if coarser, approaches to designing molds that are capable of producing surprisingly complicated devices. Here, we detail the fabrication and characterization of a microfluidic device for flow cytometry or particle sorting on a chip. Our device is a layered polydimethylsiloxane chip that uses a series of Quake valves to sort. The molds were fabricated on equipment accessible to most undergraduate labs. The techniques and physics we discuss in this manuscript can be employed to create an almost endless variety of devices for learning about complex fluid mechanics, mesoscopic, soft-matter, and biological physics.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".