Introduction 

The Analog Incubator gets its name from its analog dial control. It consists of an insulated chamber, which has optimal environmental conditions to grow and maintain cell and microbial cultures. Therefore, the Analog incubator can be used for several applications in research, medical, food, and industrial laboratories. It is used in E. coli tests, food and beverage tests, and diagnostic protocols for water. It is also used in the clinical and pharmaceutical fields and the cosmetics industry. 

The Analog Incubator includes a thermometer and a built-in temperature port to regulate temperature levels inside the chamber. Temperature stability and warming time are improved with the help of a circulation fan equipped in the chamber. A heating pilot light indicates the heater is on. The Analog Incubator is compact and is available in small and medium sizes. However, despite its smaller size, several culture plates can be incubated inside the chamber simultaneously since it holds up to four shelves.

Apparatus Features

The Analog Incubator is constructed out of steel and aluminum. The exterior part of the incubator is powder coated to prevent scratches and stains, whereas the interior is made of aluminum, which is easy to clean. A mechanical latch is present to close the incubator’s door. Analog dial control is in the center of the lower portion of the incubator’s front wall. A heating pilot light is beside the analog dial control, indicating the on/off mode of the heater. 

The incubator includes a thermometer and a built-in temperature port. The chamber’s operating temperature range is from ambient +10 to 90°C. A circulation fan is present within the chamber, which improves warming time and temperature stability. The temperature stability at 37 ºC is ± 1 °C, and uniformity is ±1.5 °C. It is available in small and medium sizes and with two removable shelves; however, it can hold up to four shelves. The shelf area is 1.26ft².

Analog Incubator Controls and Indicators 

• Temperature Adjustment Knob – it is used to change the temperature of the chamber. 
• Timer – it is used to set the desired incubation timer. It will notify the operator when the allotted time has passed at the end of the cycle.
• Heat Indicator – it is constantly on as the chamber heats up. It begins to flash when the desired temperature is approached and flashes intermittently when the device is maintaining the set temperature.

Protocol 

1. Place the sample inside the incubator and close the chamber’s door. 
2. Switch the incubator on using the power switch. 
3. Set the desired temperature of the chamber using the temperature adjustment knob. 
4. Once the temperature is set, the heater lamp will turn on and remain lit until the chamber reaches the set temperature. 
5. Wait 15 to 30 minutes for temperature re-equilibration when changing temperatures. 
6. Remove the sample from the chamber, close the chamber’s doors, and press the power off switch.

To clean the incubator’s shelves or accompanying equipment, use a lint-free cloth. Clear surfaces of all observable dirt. Disinfect the incubator using a 70% isopropyl alcohol solution. 

Applications 

The Analog Incubator is used to incubate samples in medical, clinical, pharmaceutical, and industrial laboratories. It can identify disease-causing microorganisms by taking a sample of sputum, mucus, blood, or other secretions from the patient. The sample is then placed in a culture medium and multiples inside the incubator, allowing them to be identified with greater accuracy. 

The Analog Incubator is used in the following:

• Incubating assays, such as incubating E. coli cultures, throat cultures, broth incubation, petrifilms.
• Heating histology slides.
• Warming packs for phlebotomy.
• Water quality testing.
• Food sample testing.

Literature Review 

Evaluation of the cornea’s thermal safety during accelerated cross-linking with riboflavin under strong UVA irradiances 

Sherr, Kamaev, Friedman, & Muller (2012) evaluated pig eyes cornea’s thermal safety during accelerated cross-linking with riboflavin under strong UVA irradiances. The analog incubator was used to place the sample eyes with a thermocouple inserted under the corneal flap at 33°C. After that, the eyes were irradiated with a 370 nm light source for ten minutes. Additionally, the cornea was treated with a 0.2% riboflavin-5-phosphate solution in PBS that contained 20% dextran. The rise in temperature was monitored for 10 minutes after the corneas were exposed to  UV radiation. Thermocouple tests of the ocular surface under UV irradiation with and without riboflavin revealed an initial rise in temperature before reaching a steady state. The results concluded that under high UVA irradiances, the increase in corneal temperature brought on by rapid cross-linking with riboflavin is safe.

Evaluation of halogenated energetic reactions in neutralizing bacterial spores 

Mulamba, Hunt, and Pantoya (2013) evaluated halogenated energetic reactions in neutralizing bacterial spores to study biological warfare. Bacillus thuringiensis (BT) spores were used in the study and subjected to variable temperature and iodine gas treatment to examine the mechanism for neutralizing the spores. For bacterial preparation, a 0.1 mL sample of the bacteria suspension (comprising a bacillus concentration of 3.0 × 107 CFU/mL suspended in a 40% ethanol solution in a 10 mL glass vial) was collected using an Eppendorf research pipette and placed on top of a biocidal exposure chamber. The analog incubator was used to evaporate the solution in the vial at 37°C for 12 hours, allowing the vial’s surface to be covered with dried spores for the experiment. The results indicated that heat transmission in the spore increases the halogen gas’s efficiency in the neutralization process and that higher temperatures increase spore permeability, allowing gas penetration, and accelerating the neutralization process. A mathematical model revealed that using thermal conditions alone for neutralization would require almost 1,000 °C. However, a combination of a thermal-biocidal gas process would only require elevated temperatures of 360°C to generate 80% neutralization in tens of milliseconds for the same neutralization. 

Precautions 

• Ensure that the power switch is accessible while using the incubator. 
• Connect the incubator to power sources that have a safety ground terminal.

• Don’t touch the chamber to check the temperature. 
• Avoid touching hot surfaces during high-temperature operation. 
• Ensure the operating temperature is lower than the sample material’s maximum operating temperature.
• Wear safety goggles to reduce the risk of eye injury during high-temperature operations. 

Strengths 

The Analog incubator can incubate various samples, including bacterial cultures. It provides the optimal environment for microbial samples to grow. It is compact and available in small and medium sizes, which saves laboratory bench space. Moreover, the size of the incubator also allows it to be moved around easily if needed. The incubator is easy to operate. The temperature can be easily set using the temperature adjustment knob, and the heating indicator light is used to observe if the heating inside the chamber is turned on. 

Summary

• The Analog Incubator provides optimal environmental conditions to grow and maintain cell and microbial cultures. 
• It consists of an insulated chamber with a door. An analog dial control is present outside the chamber to set the temperature. 
• The chamber also includes a heat indicator, built-in temperature port, thermometer, and a circulating fan to regulate temperature levels.
• The Analog incubator has several applications in research, medical, pharmaceutical, food, and industrial laboratories. It is used in E. coli, food and beverage, and water diagnostic protocols.
• Operators should follow safety protocols while using the incubator, such as wearing safety goggles and avoiding touching hot surfaces during high-temperature operations.

References

Sherr, E. A., Kamaev, P., Friedman, M. D., & Muller, D. (2012). Thermal safety analysis for accelerated cross-linking with riboflavin. Investigative Ophthalmology & Visual Science, 53(14), 6810-6810.

Mulamba, O., Hunt, E. M., & Pantoya, M. L. (2013). Neutralizing bacterial spores using halogenated energetic reactions. Biotechnology and bioprocess engineering, 18(5), 918-925.