Flow Control for Toxicity Testing and Exposure

The Elveflow OB1 is a pressure controller that governs how a toxicant reaches your model and for how long. It pushes a liquid dose from a sealed reservoir at a flow rate you set, pulseless and responding in about ten milliseconds. Paired with an Elveflow flow sensor, it holds that flow rate through the run. With an Elveflow MUX distribution valve, it steps between solutions in sequence: a dose, a wash, then the next dose. And because it also delivers vacuum, it can draw a gas or an aerosol across an air–liquid-interface chip. It does not supply the model or the readout; it controls the exposure. So a cell monolayer, a 3D model, an organ-on-chip, or a whole-organism device meets a defined, repeatable dose you can defend as a New Approach Methodology.

For toxicity work, the deciding factor is whether the dose stays exactly what you set, run after run. Pressure-driven control is the option that does. A syringe pump turns pulsatile at the low flow rates a long exposure uses and pauses to refill, which interrupts a wash-in or wash-out and pushes the dose around. A peristaltic pump will recirculate a compound over a long study, but its rollers add a pulse whose size tracks the flow rate. A rocker moves medium by tilting the plate, so the dose and the shear follow the rocking cycle, not a value you dial in. The Elveflow OB1 delivers continuous flow from a non-contact pressure source, reaches its setpoint in roughly ten milliseconds, and runs up to four independent lines at once. You can expose several conditions side by side and read them against each other in one experiment. Because the pressure acts on the gas above the reservoir, the instrument never contacts your toxicant.

Think of the exposure in two parts, the concentration and the timing, and the Elveflow OB1 governs both through the flow. The concentration is set by your solutions, and for a whole range at once, by a gradient-generator chip. The OB1 drives that chip’s inlets, and an Elveflow MFS or BFS flow sensor holds each inlet flow rate in a feedback loop, so the concentrations the chip lays down stay fixed through the run. The timing is set by an Elveflow MUX distribution valve. It steps one line through a dose, a wash, then the next dose, up to twelve solutions in a programmed order, and several valves chain together past twelve. So the numbers on your dosing plan come from the chemistry you prepare, and the OB1 makes sure the model receives them, at the concentration and on the timing you specified.

Yes, and doing it on a chip is faster and tighter than a plate of hand-made dilutions. Pair the Elveflow OB1 with a gradient-generator chip. The OB1 drives the chip’s inlets at held flow rates, the chip mixes one stock into a graded row of concentrations, and every chamber sees its dose at the same moment under the same flow. That is the advantage for a concentration-effect curve: every point is acquired in parallel, from the same starting material. The differences you measure come from the dose, not from pipetting scatter or timing gaps between wells. Read viability, a stress marker, or whatever endpoint your assay reports across the row, and the curve falls out of one experiment.

Yes. Gas-phase exposure uses the vacuum side of the instrument. Because the Elveflow OB1 delivers vacuum as well as pressure, it can draw a test gas through a gradient generator and across an air–liquid-interface chip. This builds a gas concentration gradient over the cells. In one lung-chip study, an OB1 held a steady negative pressure that pulled air and formaldehyde through the chip and generated the formaldehyde gradient the bronchial cells met. Viability fell and oxidative stress rose down that gradient [Frontiers in Bioengineering and Biotechnology, 2025, 1]. So inhalation and respiratory-toxicity work, on a vapour or an aerosol, is within reach on the same instrument.

Yes. The Elveflow OB1 draws from reservoirs holding a millilitre to several litres, so a long perfusion has the volume to run for days without a refill. You program the exposure sequence once, and it proceeds on its own overnight and across days. For a repeated-dose or chronic study, an Elveflow MUX recirculation valve can return the medium to its reservoir, so a costly test compound serves the whole run and is not wasted. A non-contact design keeps the pump out of the fluid path, and the programmed profile handles each dose and wash. A multi-day exposure runs without stop-start handling at the bench.

Yes. The Elveflow OB1 controls the exposure regardless of what the substance is: a drug or its metabolite, an industrial or agricultural chemical, a cosmetic ingredient, an airborne pollutant, or a nanomaterial in suspension. It drives any aqueous or biological solution through your chip or model at a set, repeatable flow rate. Its vacuum mode covers gas-phase and air–liquid-interface exposure for airborne agents. That breadth is why the same instrument serves next-generation risk assessment across pharmaceuticals, chemicals, cosmetics and the environment. It fits wherever a defined, animal-free exposure has to stand up.

Yes. A whole-organism test like the zebrafish Fish Embryo Test runs under continuous perfusion when the Elveflow OB1 supplies the flow. In one study, an OB1 with an Elveflow flow sensor perfused zebrafish embryos for the full 96-hour test and delivered the toxicant, holding the flow while the embryos developed and an automatic routine imaged each one. The perfused test scored the median lethal dose and teratogenic endpoints, and it read a stronger toxic effect than the standard multiwell assay [RSC Advances, 2021, 2]. It maps onto the OECD Fish Embryo Acute Toxicity guideline (TG 236), so it fits aquatic ecotoxicology and developmental-toxicity screening.

The Elveflow OB1 keeps the flow steady so a real-time readout stays quantitative; the readout itself comes from your assay. Place an inline sensor or assay downstream of the model. A steady flow lets you follow what the cells release, an enzyme, a secreted marker, or a stress signal, as the exposure runs, with no discrete sampling. In a fatty-liver study, an OB1 held a constant flow that carried the sample past a label-free biosensor tracking albumin, a liver-function marker [Nanomaterials, 2020, 3]. For viability or oxidative-stress endpoints read by imaging, a TTL trigger lines the OB1’s flow up with image acquisition, so dose and image share one clock. The OB1 controls the flow; you choose the endpoint and the assay.

Yes, and for toxicity that reproducibility is the whole point. With an Elveflow MFS or BFS sensor holding the flow in a feedback loop, the Elveflow OB1 replays the same dose on the same timing every run, whoever is at the bench. The dosing stops being one of the things that shifts between replicates or between labs. That transferability is exactly what a validation body checks before it accepts a New Approach Methodology. A method that gives a different answer in another lab’s hands is not one a regulatory agency can rely on. It is timely, too. The FDA Modernization Act and its roadmap to reduce animal testing, alongside parallel moves on chemicals and cosmetics, are pushing toxicology toward standardised, animal-free data. A delivery you can reproduce helps a result meet that bar.

Yes. The OB1 is chip- and model-agnostic. It pushes solution into any reservoir and through standard tubing, so it drives a commercial toxicity chip, your own PDMS device, a biosensor chip, or a millifluidic device holding whole organisms, all the same way, with any aqueous or biological solution. If your setup is unusual, tell us the model and your target flow rate, and we will confirm the configuration. Whatever exposure format your assay needs, the OB1 fits it.

The Elveflow OB1 is a non-contact pump, so the instrument never touches your toxicant or your medium. The fluid path is only the reservoir, tubing and vessel, which means fewer parts to prepare and one less route for contamination across a long exposure. The reservoirs, caps and tubing Elveflow supplies are autoclavable. You sterilise them before each run and prepare the wetted path as you would for any sterile assay. No sterility certification is claimed for the instrument itself, since it stays outside the fluid path.

Yes. Once you have entered the dosing timeline and any solution switches into the Elveflow Smart Interface, the Elveflow OB1 carries it out on its own. An overnight or multi-day exposure needs no one at the bench. Its TTL lines (0/5 V) hand timing back and forth with your other instruments. The OB1 can trigger a microscope to grab an image at a set point, take a trigger from the microscope to launch a dose, or pace a fraction collector to sample the outflow at fixed intervals. For tighter integration, the SDK drives it from Python, MATLAB, LabVIEW or C++. The flow record streams to CSV as the run goes, so the dose history is there when you analyse the endpoint.

Contact us through the form and tell us your assay, the chip or model you use, and the exposure profile you need, liquid or gas, single-dose or chronic. We will help you match the OB1 configuration, sensors and accessories to your toxicity workflow, and answer setup questions before you buy.