Injectable Microchips

Han Xiao

Introduction

Microchips, also known as integrated circuits, are essential to the ongoing development of technology. The four main parts of these circuits are capacitors, resistors, semiconductors, and transistors. The capacitors store and evenly distribute energy, while the resistors resist, or lessen, the current passing through. Semiconductors only conduct energy under certain conditions, which makes it perfect for integrated circuits. Last but not least, the transistor is the most important component, as it can increase or change electrical signals and store data. One type of transistor, the field effect transistor (FET), only contains two layers of semiconductors. A current flows through one layer of semiconductors which is named the channel. At one point, the current is met with a gate connected to the second layer, which can either amplify or reduce the strength of the current to execute a basic function such as powering on and off. Finally, the current exits the transistor through a section called the drain. FET transistors are often preferable over other transistors because of its ability to stabilize temperatures and produce less noise when being used.

History

The origin of microchips came from vacuum tubes in the early 1900s. Triode vacuum tubes were much larger, falling between anywhere from 1-6 feet tall, but had similar components as a current integrated circuit. The tubes were extremely inconvenient because they used up a lot of space and energy. They also had to be replaced frequently due to their fragile nature. The first transistors were invented in 1947, and a decade later, the first microchip came into existence. Around the same time from 1958-1959, Jack Kilby and Robert Noyce developed similar models of the integrated circuit. The main differences between their models was the material the semiconductor was made of. Kilby developed a model which had germanium as the material of the semiconductor while Noyce used silicon. Noyce’s model was eventually accepted as the official model because silicon was easier to produce at the time and could withstand higher temperatures. After the discovery, more and more transistors could fit onto the same sliver of silicon each year with the advancement of technology. Transistors were made so incredibly small to the point where they can’t be seen by the naked eye. In 1965, Gordon Moore predicted that we will be able to pack twice as many transistors on a semiconductor of the same size every 2 years; this is now known as Moore’s law. Some in 2021 have predicted Moore’s law will die by 2025 because of the pace at which technology is advancing. Current graphs have shown that we are starting to fall off the predicted curve of how many transistors can fit per square millimeter. Others argue that Moore’s law is alive and well, with a few major companies at the top of the curve each year. As of May 6th 2021, IBM, a company founded in New York, has created the smallest known non-injectable transistor at a size of 2 nanometers. An advantage that smaller microchips bring are more portable devices and increased speed of those devices. The main concern is whether or not a smaller integrated circuit will function properly. This is due to the thinning of the gates and channels throughout the chip. They will become so thin that they can no longer control the amount of voltage that passes through them, leading to too much information being corrupted.

Injectable Microchips

In order for microchips to be injected into the muscle, the first step is to protect the circuits from environments with high moisture. In 2019, scientists at Columbia University developed flexible, waterproof transistors, which is the key to creating injectable microchips. These microchips are intramuscular; it goes into your muscle and all the way underneath your skin. The blood and lipids in your muscle create an environment that is too damp for regular microchips to function in. To make the transistors waterproof, the original semiconductor material of the channels inside were replaced with a thin encapsulation layer derived from monocrystalline. Monocrystalline is a single crystal arranged in a continuous, lattice-like pattern. Due to the material being a single, interconnected crystal, monocrystalline provides the right properties needed to create these microchips. The flexibility of the microchip brings the advantage of being able to squeeze through small crevices in your body system. At the end of May 2021, researchers at Columbia University developed the smallest injectable microchips. The chip is coated entirely with a thin layer of plastic (the type depending on biocompatibility). Since ultrasound is used to communicate with and power the chips, there needs to be a stable connection with the integrated circuit. To enhance the connection between the ultrasound and the circuit, a layer of gold covers both sides of the chip. These intradermal microchips are the size of a dust mite, or 1 millimeter in size. They are currently only being used to measure body temperature, but they will most likely be able to detect deadly diseases after more development.

Conclusion

As of now, Columbia’s intramuscular injectable microchip can only measure body temperature. In the future, scientists hope to go as far as detecting deadly diseases such as cancer. The expansion of possibilities of microchips are limitless, and they might be able to save lives one day. A different type of microchip, RFID, has been injected subcutaneously in people’s palms since 2015 in Sweden. They are different from the intradermal microchips in that their site of injection is in the fatty layer of your skin, while intramuscular microchips are placed inside the muscles. In addition to the site of injection, the RFID chips differ from Columbia’s microchip in functions as well. They act as wallets, keys, personal identification, and transportation tickets for many people in Sweden. Although the number of people with these injections rose dramatically in 2015, these integrated circuits are still more commonly used to track animals and livestock. Seeing as this piece of technology is so accessible in many situations, it may just take over our lives. Regardless of what our fears and hopes are for the future, we know it holds immeasurable potential for such a tiny (and getting tinier) device.

Citations

Manzanetti, Zoe. “Regaining Control of Technology One Microchip at a Time.” Governing, Governing, 21 Apr. 2021, https://www.governing.com/next/regaining-control-of-technology-one-microchip-at-a-time.html.