BMS1029 Current Topics In Biosciences


Title of the project

Touch Screen Devices and Microbial Contamination

Null Hypothesis

Touch screen and keypad mobile phones will be free from microbes

To determine if there are bacterial pathogens on the surfaces of touch-screen devices.

To determine the presence of microbes on touchscreen devices.

To compare and analyse between two devices that have more microbes on their surfaces, such touch screen device or keypad.



The mobile phone has become an indispensable material good in recent times.

The technology has advanced to the point that smartphones are now more capable of transferring any type of language as well as functions like sending and receiving messages, emails, chat and surfing the web.

Modern smartphones have a touchscreen that can be accessed by finger touch.

This makes it more likely that the touchscreen can be contaminated by microorganisms present on the hands.

During the research that followed, it was found that not only were the fingers being touched by the phones, but also the eyes, ears, and mouth came into contact with them.

It was found that the keypad device had a similar microbial burden to the smartphone.

In addition, the electromagnetic radiations emitted by smartphones and the mechanical waves attract microorganisms.

The research suggests that the presence of microbes on the surface is also dependent on personal hygiene and occupational environment.

This could be due to the fact the device was being used within a medical environment, which is very susceptible to harboring large amounts of microbial population.

It was also discovered that smartphones can emit electromagnetic waves. Therefore it was necessary to examine how electromagnetic waves affected both the microbial populations present on the touchscreen devices and the keypad devices.

The research on keypads revealed that they could also be responsible in cross-contamination in cases of hospital-acquired diseases.

These infections can be reduced by regular cleaning and proper disinfection.

This study is designed to identify and analyze the microbial load present on the surface of these phones’ screens.

This paper will compare and contrast the microbial load on the touch screen and keypad of the phone device.

This research is expected to yield key results. It will allow us to compare the microbes found on the various devices. We will then use wipes to determine the number of microbes left after each wash.

The microorganisms that grow on the plates can also be expected to increase.

The Progress to Date


The first step was to collect touch screen devices and keypad devices in order to determine the microbial loads.

For the purpose of microbiological recovery, a 25 cm2 surface area was considered. A handmade filter frame was made from sterilized UV paper and rays.

To collect the microbes, a sterilized dry cotton swab had to be rubbed on the mark surface about 10 times.

This was then immersed in 0.9% NaCl, which was sterilized and vortexed for 2 minutes.

This method was chosen because it is a standard laboratory procedure for determining the recovery of the microbial population and its counts.

This improves the ability to identify the microorganisms.

The swab that was collected was spread on the plate containing nutrients agar.

This was then incubated at 37°C aerobically for 48 hours. The saline solution of 100 ul was then stirred at 10,000 rpm for 5 minutes.

The pellet was then suspended once more in a 100 ul saline mixture and poured into the plates.

For this, a pour-plate technique was used.

This is a convenient method because it allows the microorganisms to grow on the surface and in the agar.

Spread plate technique should not be used as it will only permit microbes to grow on its surface.

Preparation of agar

Peptone water was used to prepare the nutrient agar in an aseptic manner.

This was the preferred culture medium because it is universal and can be used by most cultivable microorganisms.

The nutrient agar plate contains complex nutritional components that enable different types and strains of bacteria and fungi to grow there.

The culture solution was serially diluted to a 10-7 dilution factor for sub-culturing.

After that, the dilutions of 10, 5, and 10-6 were plated.

This was because lower dilutions than this would produce a lawn for culture, while higher dilutions will give less colonies.

Streak plate

To prepare the steak plate, the colonies had to be poured on top of the previously prepared plate.

To identify, study and test microbes, it is necessary to collect details from each of the populations.

After pouring, a streak plate and then the spread plate were collected.

These plates were used to collect the results and then calculate the number of selected plates.

The chosen plate was parboiled with a 10-2 dilution factor. It contained three different colonies that were to be sub-cultured.

After streaking at 37?C, the plates were incubated for 24hrs.

Transferring the culture from the previous plate was enough to sub-culturing on a new plate.

This was then incubated at 37oC for approximately 24 hours.

Sub-culturing can be used to extend the lifespan of the cells present in the culture.

Sub-culturing involves the use of 10-2 diluted.

Identification of the culture

Gram staining is a technique that distinguishes between gram-negative and gram-positive bacteria. It was used for the identification of the microbial community.

This was then viewed under the microscope using the 10X lens.

This enabled us to identify the colony’s morphology and growth characteristics.

This allowed for the identification of the biochemical profile which included the catalase and oxidase enzymes, coagulases, citrates, and indole tests.

Next Step

Safety precautions must be observed when working in a laboratory. They should be established at the outset. But, there are some practices that can lead to mistakes during the experiment.

These may include:

The preparation time of the nutrient gar might be too long for some people, and the agar may spill out in the microwave oven.

Since the culture was hot, this experiment was repeated multiple times. This led to negative results.

The necessary precautions were taken during sub-culturing to prevent cross-contamination. Every time culture is transferred, there is the possibility of contamination (Rana et. al.

Refer to

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How to disinfect the iPad.

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M. Koroglu and S. Gunal. Yildiz. F., Savas. M. Ozer. A. and Altindis. M.

Comparison of touch-screen and keypad mobile phones/devices as potential risks for microbial infection.

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The risk of microbial contamination is significantly higher for keypad phones than for touch screen phones.

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