Drip Flow Biofilm Reactor®
High Air-Liquid Interface Biofilm Reactor for Low Shear Research
The Drip Flow Biofilm Reactor® is the standard platform for growing biofilm under low shear conditions at the air-liquid interface, recognized in ASTM E2647 and used across dental, medical device, food safety, and general biofilm research. Where the CDC Biofilm Reactor generates turbulent, high-shear conditions, the DFR creates a fundamentally different environment. Media drips continuously onto the coupon surface via gravity, producing extremely low shear with a short hydraulic residence time. This makes the DFR the appropriate choice when modeling surfaces exposed to thin fluid films, draining flows, or mouth and respiratory tract environments.
The reactor consists of four or six independent parallel channels machined into a rectangular base held at a 10-degree angle by an anodized aluminum support stand. Each channel holds one standard 25mm x 75mm x 1mm slide-format coupon (18.75 cm²), retained by two pegs and covered by a polycarbonate lid with an O-ring seal, a Mininert® valve influent port, and a bacterial air vent for sterile gas exchange. Channels are independent, providing separate sampling opportunities within a single run. The entire system is autoclavable and reusable.
DFR 110-4PET
4-channel PET (polyethylene terephthalate) Drip Flow Biofilm Reactor® with Reactor Support Stands
Applications
The DFR is used across a wide range of biofilm research and product development applications. Its low shear, high gas-exchange environment makes it particularly well suited for microsensor monitoring of microenvironmental gradients within the biofilm, high biomass production for cryosectioning and structural analysis, and general biofilm studies where thin-film or low-flow conditions are relevant. The reactor models environments including food-processing conveyor belts and produce sprayers, catheters, lungs with cystic fibrosis, and the oral cavity, making it a standard choice for dental and oral care material evaluations including toothpaste, mouthwash, and implant surface testing, as well as indwelling medical device evaluations such as catheters and stents. Each independent channel allows multiple treatment conditions or concentrations to be run simultaneously within a single experiment.
DFR 112 Catheter and Stent Modification
The DFR 112 is a modified version of the Drip Flow Biofilm Reactor designed specifically for catheter and stent biofilm studies. Sample sections are mounted inside the reactor channels using female luer and barbed fittings, with multiple barbed fitting sizes included to accommodate a range of catheter and stent outer diameters. The elevated injection port valve provides sufficient distance above the sample for proper droplet formation, preventing direct nozzle contact with the sample surface.
The DFR 112 supports two independent flow paths simultaneously. Flow over the exterior of the catheter or stent surface is delivered via the standard drip mechanism through the injection port. Flow through the lumen of the sample is enabled by a separate alternate influent port on the exterior of the reactor, using 1/8″ luer fittings sized for size 16 tubing. This dual-flow capability allows researchers to study biofilm formation and treatment efficacy on both the inner and outer surfaces of tubular medical devices within the same experiment. The DFR 112 is available in all three reactor materials and both four-channel and six-channel configurations.
DFR 110-6AL
6-channel red-anodized aluminum Drip Flow Biofilm Reactor® with Reactor Support Stands
Drip Flow Biofilm Reactor® Models at a Glance
| Model | Channels | Reactor Material | Catheter / Stent Capable | Included With Every Model |
|---|---|---|---|---|
| DFR 110-4 | 4 | Polysulfone | No | Reactor body, ported lids, lid gaskets, bacterial air vents, glass slide coupons (50 pc.), slide removal tool, glass flow breaks, reactor support stand, 6-month limited warranty |
| DFR 110-4PET | 4 | PET | No | |
| DFR 110-4AL | 4 | Anodized Aluminum | No | |
| DFR 110-6 | 6 | Polysulfone | No | |
| DFR 110-6PET | 6 | PET | No | |
| DFR 110-6AL | 6 | Anodized Aluminum | No | |
| DFR 112-4 | 4 | Polysulfone | Yes | Reactor body, ported lids, lid gaskets, bacterial air vents, glass slide coupons (50 pc.), slide removal tool, glass flow breaks, reactor support stand, female luer and barbed fittings (assorted sizes), 1/8" barbed luer adapters, 6-month limited warranty |
| DFR 112-4PET | 4 | PET | Yes | |
| DFR 112-4AL | 4 | Anodized Aluminum | Yes | |
| DFR 112-6 | 6 | Polysulfone | Yes | |
| DFR 112-6PET | 6 | PET | Yes | |
| DFR 112-6AL | 6 | Anodized Aluminum | Yes |
Watch instructional videos on the DFR (Produced by the Center for Biofilm Engineering at MSU):
Reactor Material Selection
Polysulfone is the original reactor material, a yellowish-clear thermoplastic that is autoclavable and resistant to acidic chemistries. It is the most chemically resistant of the three options but is also the most fragile. It is a crystalline plastic that can crack or craze under physical or thermal stress, and should be handled with the same care as glass.
Black PET (Polyethylene Terephthalate) has similar chemical resistance to Polysulfone but is significantly more resistant to physical and thermal stress. As an amorphous plastic without fracture planes it handles rough use much better than Polysulfone and is also a slightly less expensive option. PET is opaque and autoclavable. Both plastic options will eventually degrade with repeated autoclave cycles.
Anodized Aluminum offers the highest resistance to both thermal and physical stress and is the best choice for high-cycle labs. The anodized coating is very thin and can be scratched easily, Once it is removed, the underlying aluminum is highly reactive in salt-containing solutions such as growth media. The coating will also degrade with repeated exposure to acidic conditions but can be restored by reanodizing.
Replacement Parts
All Drip Flow Biofilm Reactor components and parts are available for purchase individually. Check out our full list of replacement parts:
Slide Sample Coupon
Many materials are already available, and we are always willing to try new materials for specialty projects! Check out our full list of available materials and pricing:
ASTM Standard Method using the Drip Flow Biofilm Reactor
Standard Test Method for Quantification of Pseudomonas aeruginosa Biofilm Grown Using Drip Flow Biofilm Reactor® with Low Shear and Continuous Flow:
