The Maze Engineers Vapor Chamber adapted from an alcohol vapor chamber created by Mortan et al 2014.

The primary objective of the chamber is to expose rodent subjects to vaporized liquid in a controlled, continuous, and developmentally-timed manner. Specifically, it aimed to:

  1. Ensure Consistent Dosage and Environmental Control:

    • Maintained precise vapor concentrations, airflow, humidity, and temperature to reduce variability.

    • Control duration, frequency, and intensity of exposure.

2. Minimize Stress Compared to Injections or Oral Administration:

    • Vapor inhalation is less invasive than other administration routes, making it ideal for long-term exposure during critical developmental periods.

3. Use any volatile liquid, including ethanol

The system comprises of:

    • 2 enclosures with  + vapor inlets + air outlets
    • A vapor delivery: Air pump with T connector; 2 air flow regulators and a filter flask

Price & Dimensions

Vapor Delivery Apparatus

$ 4,990.00

+S&H
  •  2 Enclosures: Acrylic, 22 L x 32 W x 14 H inch + door + vapor inlets + air outlets
  • Vapor delivery: Air pump with T connector; 2 air flow regulators; filter flask

Documentation

Introduction

In the original publication, the vapor chamber was designed to model alcohol exposure during critical periods of development in mice. This approach is designed to replicate human prenatal alcohol exposure spanning all three trimesters, offering a powerful tool to study Fetal Alcohol Spectrum Disorders (FASDs) in a controlled and reproducible manner.

The vapor chambers were configured to house up to six mouse cages at a time. This setup facilitates the delivery of ethanol vapor in a manner that minimizes stress to subjects by avoiding the need for injections or oral gavage. The system allows for continuous exposure of subjects. This design is especially advantageous for researchers working with genetically modified mouse strains, as it supports consistent, long-term exposure across critical developmental windows.

Key experimental observations from using this vapor exposure model revealed that pregnant mice (dams) developed metabolic tolerance to ethanol, while the neonatal pups did not. Despite significant ethanol exposure, no notable differences were detected in physical parameters such as fetal and pup weights, placenta weight, litter size, or mortality, suggesting the chamber provides a physiologically stable environment. This minimizes confounding effects from stress, handling, or other non-exposure-related factors, enhancing the reliability of developmental outcome measurements.

In conclusion, this methodology provides a robust and ethically considerate approach to modeling prenatal and early postnatal alcohol exposure. Its relevance lies in enabling in-depth exploration of the mechanisms driving FASDs, including potential genetic and neurodevelopmental pathways. By mimicking human-like patterns of alcohol exposure and reducing experimental variability, this model serves as an essential tool in both basic and translational research on the effects of developmental ethanol exposure.

Apparatus and Equipment

The apparatus consists of two acrylic chambers, 1 test chamber, and 1 control chamber, each with the dimensions of 22 L x 32 W x 14 H inches. Each chamber has a door and vapor inlet and air outlet. Each chamber can hold up to 6 standard shoebox mouse cages.

Vapor is delivered to the test chamber using an air pump connected to an airflow regulator and filter flask containing ethanol. The control chamber has air delivered to it from the air pump. The air pump has a flow rate of

Testing Protocol

  1. Connect chambers and tubing to the air pump as outlined in the include manual
  2. Calibrate exposure chambers and assess vapor level:

    • Prepare Vapor Source:
      Pour 600 ml of  volatile test chemical into a filter flask, insert an aeration stone, and connect the flask’s side arm to the chamber’s air inlet tubing.

    • Activate Airflow:
      Close the chamber doors and start the air pump to begin circulating air through the system.

    • Regulate Air Mixture:
      Adjust the airflow so that the amount of air bubbling through the ethanol is roughly half the volume of the plain air being mixed with it. The total airflow of the ethanol-air mix should equal the flow of plain air.

    • Equilibration Period:
      Allow at least 30 minutes for the vapor concentration inside the chamber to stabilize before taking any measurements.

    • Measure Ethanol Concentration:
      Using an 18G needle and a 60 ml syringe, draw 5 ml of chamber air through a septum, then dilute it to 60 ml with room air (1:12 dilution). Test the sample (for example, for alcohol, use a breathalyzer, following the manufacturer’s instructions. Adjust dilution if needed based on expected alcohol levels.

    • Target Vapor Concentration:
      Tune airflow regulators to achieve desired vaor level (for ethanol this is approximately 4.5–5 g/dl, which serves as the standard exposure level).

3. Vapor Exposure publication example:

    • Prenatal Exposure:
      Pregnant dams are exposed to ethanol vapor for 4 hours daily starting at 10 AM during the light cycle (6 AM–6 PM), except on the day of birth to prevent pup mortality.

    • Maternal Monitoring:
      Dams are weighed on gestational days 5, 13–14, and 18–20 to monitor pregnancy progression. Bedding is changed on weighing days to minimize additional handling.

    • Food Maintenance:
      Daily replacement of food pellets is performed for ethanol-exposed groups to prevent ingestion of ethanol-contaminated feed.

    • Postnatal Exposure:
      From postnatal day 1 to 12 (P1–P12), both dams and pups are exposed together to ethanol vapor for 4 hours per day, starting at 10 AM. No exposure is given on the day of birth.

    • Pup Monitoring:
      Pups are weighed on P2, P8, P12, and P25. Bedding is changed on P8 and P12 to reduce stress from frequent handling.

    • Post-Exposure Housing:
      After the final exposure on P12, cages are transferred to standard animal housing facilities.

Literature Review

Investigation of olfactory learning in Aedes Aegypti mosquitoes 

Vinauger, Lutz, & Riffell (2014) investigated the role of olfactory stimuli in searching for the blood meal in  A. aegypti mosquitoes. The study was composed of three groups; the control group, untrained, and trained mosquitoes. A Mosquito Olfactory Maze was utilized for training and task performance. The individual and group training sessions were conducted; mosquitoes were exposed to conditional stimuli, which was paired with a blood reward. The heat was used as an unconditional stimulus to induce blood-feeding responses in mosquitoes.  The results of the individual training sessions revealed that only two feeding trials were enough for A. aegypti to create new memories, which will stay for at least 24 hrs. Trained mosquitoes were able to create an association between the conditional stimuli (L-lactic acid ) and unconditional stimuli and retain them for 24 hrs. The results of the group training experiments to the L-lactic acid revealed that individually tested mosquitoes but group-trained performed similarly to individually trained subjects. It was observed that different odors could not be used as conditional stimuli. L-lactic acid and 1-octen-3-ol were observed to be associated with obtaining blood meal while not being innately attractant, while the inverse was observed of innately aversive odors.  The study concluded that learning is a vital factor in odor responses in the A. aegypti

References

Morton RA, Diaz MR, Topper LA, Valenzuela CF. Construction of vapor chambers used to expose mice to alcohol during the equivalent of all three trimesters of human development. J Vis Exp. 2014 Jul 13;(89):51839. doi: 10.3791/51839. PMID: 25046568; PMCID: PMC4132936.