Microbes know the non-linear tricks, and so do we!
New 3D printable container with convenient tweezers is now available to fight the microbes. The product is designed to decrease the probability of payment-mediated microbes ending up on the hands. The idea is to contain possibly contaminated money and other small items inside a single-hand-operated container, and manipulate the items with the inverted tweezers provided. The tweezers can also be used to interact with payment terminals. The installation of the tweezers in the proper orientation on the backside of the container locks the container. This way, the accidental opening of the container can be avoided, functioning also as a reminder to use the tweezers.
Depending on your needs, you can vary the size of the model. Typical payment cards fit in the 100% model, but smaller scaling such as 75% is more convenient to handle and works well with coins and banknotes. You can use the container and the tweezers as such. But if you want to take part in the innovation, you can design your own sub-containers and tweezers. If you decide to print one, read the provided preparation guidelines carefully, and practice at your home to use the product. For example, folding banknotes inside the container might require a little experience. The container will also open and close easier if the thumb-operated knob is pushed from the right direction. Playing with the product is the best teacher. It is recommended to wash the container regularly with detergents, sanitizers could be used as well.
The described product alone cannot provide 100% protection against microbes. However, in combination with other hygiene measures, it can decrease the probability of microbial transmissions on hands. The product is lab-tested on a small scale, and the lab efficiency of the product was found to be about 90% in reducing cash-mediated microbes. Vaakalintu Ltd cannot guarantee the proper making and use of the product, why Vaakalintu Ltd cannot provide any estimations about its efficiency or functionality in general use.
Remember to read the MyMiniFactory Blog post for furher details, click here!.
Want to spread awareness about the non-linear tricks we humans can do? Shirts and coffee mugs decorated with the demonstrative images are available on Vaakalintu-Product Store, click here!
I hope the container and tweezers are helpful and enjoyable to 3D print. Before using the 3D print outside, remember to practice at home with real money. I wish you all good luck and a bright future. Do not forget the other hygiene measures. Remember: Microbes know the non-linear tricks, and so do we!
Ilmari Tamminen, Entrepreneur
Vaakalintu Ltd, Inventions for you!
In April 2020
90% lab efficiency, how the product was tested
Wearing a respirator and nitrile gloves, later ones frequently sterilized with an alcohol solution, 48 Petri dishes were casted with a microbial culturing medium. The medium consisted of about 8 mg/ml bouillon and 40 mg/ml agar hydrogel, both bought from a grocery store. First, 10X concentrate of the bouillon was prepared by dissolving proper amount of the conencentrate into boiling water. The mixture was then centrifuged for a while to precipitate solid particles. Fats were solidified on the surface, under which the clear supernatant was transferred to another container. An appropriate volume of the bouillon concentrate was boiled in water with the agar powder for a few minutes. More water was added to replace the evaporated liquid, then the mixture was re-heated a little, after which the hot solution was cast in the Petri dishes. A hot air blower was used near the casting to create upward air currents decreasing the risk of airborne microbes settling onto the Petri dishes. The Petri dishes were equilibrated until the surfaces of the mediums became solid but tacky, keeping the dishes upside down with their lids closed in an electric oven adjusted to +25 Celcius.
All the Petri dishes were divided into two groups named "Bare hands" and "Container" (N = 24 + 24). All the Petri dishes were visually divided into two equally large halves with a marker, the other halves being the "Control" areas (N = 48) to account for the experimental microbial background load. Three coins and one banknote were heavily contaminated with soil bacteria. Only one of the coins contained brass, a possible source of microbicidal copper, which effect was considered insignificant. Water was intensively mixed with fertile soil, the suspension was centrifuged, and a tissue paper was damped with the supernatant. At the beginning of each experimental round, both sides of the coins and the folded banknote were touched on the damp tissue paper and transferred to a plate. Hands were washed with soap water and rinsed twice with water, then dried with tissue paper. Three buckets were used for the job, and the small amount of transferred soap into the rinsing buckets was considered insignificant. All the hand contacts with the culture mediums were done near the upward air current produced by the hot air blower. After the wash, the five fingertips of the right hand were touched with the control area of a Petri dish. Then the coins and the banknote were transferred from the plate to another and back, after which the "Bare hand" area of the same Petri dish was touched with the fingertips. The procedure was repeated.
After the 24 Petri dishes were used, the same process was repeated but now with the container and the tweezers. Now the coins and banknote were transferred from the plate into the container with the tweezers operated by the right hand. After installing the tweezers on the container to lock it, the container was shaken a couple of times the opening pointing downwards, and the interface between the drawer and the container was swiped with the fingertips of the right hand. Then the tweezers were used to return the money on the plate, after which the "Container" area of a Petri dish was touch with the right-hand finger tips. After the whole series was ready, all the Petri dishes were incubated in +25 Celsius for two days. Open glass of water was kept inside the oven to supply air moisture, and the oven door was slightly open letting oxygen in.
Wearing a P3 respirator and protective glasses to avoid possible legionella bacteria and other pathogens, a marker was used to count the microbial colonies. Counting casting imperfections was avoided, and the number of colonies in irregular bacterial masses was approximated by surface area. To count the p-value estimations for the statistical significance between the "Container" and the rest of the data, 10 000 000 permutations for each test were computed in R 3.6.3 for the absolute median differences. The "Container" vs "Bare hands" p-value est. was 0.00; the "Container" vs "Control" p-value est. was 2.28e-05; both indicating statistically significant results. To calculate the median differences, the experimental background, the median of the "Control", was first subtracted from the other medians. The container seemed to decrease the cash mediated microbial transmissions on the fingertips by 90% on average. Once during the experiment, the 3D print was accidentally touched with dirty hands right after recontaminating the money, which actually better simulates real-life usage.