Introduction

The invention of Edible Electronics is a vast technological and gastronomic achievement intended to impact how people perceive edible food significantly. Edible electronic devices are made of natural or synthetic food-based ingredients which are broken down, eaten and metabolized in the body to execute their functions. The way towards ingestible electronics started in the early 1950s as sensing and telecommunication devices using Germanium and Silicon transistors. In 2017, the USFDA approved the 1st ingestible camera to dissolve the digital system within the body without recollection to monitor the internal metabolism. The ultimate goal of green research as a precursor to edible electronic devices was proposed by Bauer and colleagues in an article published in 2010. Edible Electronics in the past has been envisioned as a technique that is not only eco-sustainable, competitively priced and energy-efficient, but also safe for intake and degrades inside the body after it has served its purpose through digestion or even metabolization.

According to US scientists, graphene patterns on ordinary materials like food, paper, cloth and cardboard are used for creating a new class of edible electronics. In addition, several other dietary ingredients are being studied for suitable applications in edible electronic equipment, including monosodium glutamate to increase the electrolyte density, cellulose as a binding material, vegetables for energy drinks, liquid electrolytes for barbecue sauces, jelly, cheese gels, electrolytes, gum candies and packaging materials. The majority of materials generated from natural foods on the other hand, have low electronic conductivity, limiting their utility as DC conductors in edible electronic platforms.

A group led by Giorgio Bonacchini of the Istituto Italiano di Tecnologia (IIT) in Genoa, Italy developed an embossed organic electronic element on transfer paper and are now transferring these components to edible objects like pharmaceutical tablets or pieces of fruit using more economical techniques to track our health and food. In addition, edible supercapacitors have been developed by researchers in the USA from food-safe materials. This team has developed new Laser-Induced Graphene (LIG) technique, which uses a computer-controlled laser to transform various materials into porous graphene foams. Conductivity of the materials should be considered before researching, which could be used as a kind of ID tag on food. Edible circuits have previously been etched onto the surface of food by researchers, paving the path for RFID tags on delicacies that might assist in tracking food from farm to fork. Currently, Edible Electronics seem to be a collection of edibles, synthetic and functional food materials at an experimental stage. However, this concept will be more widely accepted if active and swallowable elements (e.g., medicines, food additives made from grass ingredients) are treated with precise nutrition benchmarks (with recommended daily intake.)

Components of Edible Electronics

In most of the cases, edible materials can inherently possess electronic or ionic conductivity, or a combination of both. Due to their promising electronic functionality and significant level of Reference Daily Intake (RDI), several edible metals and minerals can be accounted as a prospective source to fulfill that role.

Edible Electronics consists of resistors, conductors, transistors, capacitors, batteries, antennas, sensors, inductors, conductive binders (interconnectors), substrates and dielectrics. Thus, the basic framework is the building block of electronic devices which consists of a functionally active and passive element, circuits, sensors, power supplies and communication strategies.

Communication strategies involved in Edible Electronics are applicable with a passive device identical to a radiofrequency system made of edible conductors exploited in powering the simple circuit. In addition, Near Field Communication (NFC) and Radiofrequency Identification (RFID) also carry out data transmission signals, whereas acoustics communication utilizes Piezoelectric Transducers. Another signal transmission is through intrabody communication to the user employing the conductive property of the body through optical visual feedbacks like electrochromic/thermochromic displays or Light-emitting devices to the products.

Sources for developing Edible Electronics

The material should be of the highest quality, as evidenced by the established protocols used to assess its edibleness and safety, as well as its biochemical and organoleptic qualities. Conductors, which are also a part of interconnections and electrodes, are vital for the system. When it comes to edible electronics, there are two types of conductors: electronic and ionic conductors. Generally, edible substances can have electrical or ionic conductivity, which is the basic mechanism behind ionic movement. There is a certain legalized list of edible materials recommended for an electrical utility. This ranges from organic compounds like cellulose, chitin, activated carbon and shellac to tiny gold, silver, magnesium and zinc elements. The dyes and natural pigments are also appropriate candidates for semiconductor devices. For example, carbonized cotton, carbonized protein and carbonized cellulose have practical applications in constructing resistors, inductors and antennas.

Electronic conductors are primarily made up of edible and nontoxic metals (Gold, Silver, etc.), non-metallic chemical stable carbon (activated carbon), and melanin pigments. Ionic conductors are meant for signaling and communication. Electrolytes (Salt, base, acid) and biologically doped polymers (DNA or polypeptides) batteries, Supercapacitors and fuel cells are made of electrolytes or edible ions intended for powering up the system that creates potential within the stomach. In sensing tools and transistors, electrolytes are also a part of the system. Edible electrolytic matrices of chitosan, cellulose, agarose and gelatin with dispersed salts are the source of transistors. Dielectric materials are the elementary components of construction as substrate, insulation and encapsulating substances.

Applications of Edible Electronics in Biomedical and Food Sector

Edible Electronics are classified into two broad categories based on their enactment; first applies to food applications (External environment before consumption) and other biomedical/ pharmaceutical applications (ingested Within the GI tract.)

Biomedical Applications

It monitors the GI tract’s health status in performing the crucial task of diagnosis from testing to therapy and regulated drug delivery. E.g., Detecting bleeding in the GI tract enhanced the diagnosis possibility and accuracy of the GI tract and reduced the detecting time of hemorrhages and lesions.

Food Applications

Its edible, innocuous and ecologically friendly character allows it to be used in the food sector for quality control, safety regulation, supply chain, reducing extra packaging, robustness and pollutants, as well as chemical analysis. All of this data is transmitted in real-time. E.g. Smart tagging of the food industry produce. Broadly, it applies for the following purposes.
• Detection of the pH and temperature of GI fluid;
• Monitoring core body temperature;
• Observation of Acidity in the stomach and intestine;
• Examination of concentration of glucose in the GI fluid;
• Perceiving the swelling properties and dissolution properties of the gut mechanism;
• Simulation of food and drinks intake pattern using gastric temperature;
• Diagnosing the gastrointestinal diseases;
• Assessing the gastrointestinal bleeding;
• Detection of adenoma – non-cancerous tumor;
• Analyzing the enzymes and microbial communities from gas sensors.

Some of the currently available types of edible devices and their applications are as under:
• pH value measurement devices intended for detecting pH variation in the stomach;
• Temperature determination devices for sensing intestinal dissimilarities;
• Gastrorrhagia determining capsules;
• Edible carbon paste biodevice helps in examining the acid level of the stomach and intestine;
• Edible hydrogel device with temperature sensor for detecting food and drinks intake pattern;
• X-ray imaging capsule for detecting colon impairment;
• Ingestible micro-bioelectronic device (IMBED) used as a biomarker with an ability to detect the gastrointestinal abnormalities.

Advantages of Edible Electronics

• Cost-effective
• Environmentally friendly
• Robustness
• Eliminate additional packaging in food produce
• Harmless
• Remote health care Monitoring
• Safe Ingestion
• Digestible/ eliminate device recollection
• Real-time Communication

Conclusion

Edible Electronics would be an aggregation of novelty in Information Technology, Medical, Food and Material Science to combat the difficulties faced by the humans and it would be a great boon to Food, Pharmaceutical, and Biomedical Industries. One can anticipate that the holistic approach of this invention is the greatest advantage in collaborating with a broad spectrum of the scientific community. Major concerns need to be tackled, which start from the selection of edible material to the approval of the same material for the ingestion with adequate electronic properties and suitable processing capability. The evolving device would be a potential tool in fundamental areas of life, health and wealth. Its electronic functionalities are ingested in humans with no harm to the milieu.

References

1. Bonacchini, G. E., Bossio, C., Greco, F., Mattoli, V., Kim, Y., Lanzani, G., & Caironi, M. (2018). Tattoo-Paper Transfer as a Versatile Platform for All-Printed Organic Edible Electronics. Advanced Mateials, 1706091, 1–8. https://doi.org/10.1002/adma.201706091

2. Lu, B., Yuk, H., Lin, S., Jian, N., Qu, K., Xu, J., & Zhao, X. (n.d.). Pure PEDOT : PSS hydrogels. Nature Communications, 2019. https://doi.org/10.1038/s41467-019-09003-5

3. Sharova, A. S., & Caironi, M. (2021). Sweet Electronics : Honey-Gated Complementary Organic Transistors and Circuits Operating in Air. Advanced Mateials, 2103183, 1–9. https://doi.org/10.1002/adma.202103183

4. Sharova, A. S., Melloni, F., Lanzani, G., Bettinger, C. J., & Caironi, M. (2020). Edible Electronics : The Vision and the Challenge. Advanced Material Technologies. https://doi.org/10.1002/admt.202000757

5. Wang, X., Xu, W., Chatterjee, P., Lv, C., Popovich, J., Song, Z., Dai, L., Kalani, M. Y. S., Haydel, S. E., & Jiang, H. (2016). Food-Materials-Based Edible Supercapacitors. Advanced Material Technologies, 1–7.
https://doi.org/10.1002/admt.201600059

6. Wu, Y., Ye, D., Shan, Y., He, S., Su, Z., Liang, J., Zheng, J., Yang, Z., Yang, H., Xu, W., & Jiang, H. (2020). Edible and Nutritive Electronics : Materials, Fabrications, Components, and Applications. Advanced Material Technologies, 2000100, 1–28. https://doi.org/10.1002/admt.202000100

7. Xu, W., Yang, H., Zeng, W., Houghton, T., Wang, X., Murthy, R., Kim, H., Lin, Y., Mignolet, M., Duan, H., Yu, H., & Slepian, M. (2017). Food-Based Edible and Nutritive Electronics. Advanced Material Technologies, 1700181, 1–7. https://doi.org/10.1002/admt.201700181

About the Authors:
1. B. Kamalapreetha,
Research Scholar

2. Dr. R. Mahendran,
Associate Professor and Head
Centre of Excellence in Nonthermal Processing,
NIFTEM-Thanjavur.
Email ID: mahendran@iifpt.edu.in

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Author

An editor by day & dreamer at night; passionately involved with both print and digital media; Pet lover; Solo traveller.

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