We are living in the Golden Age of Silicon, where flows of electrons on chips dictate our interactions, our economy, and our health. The promises of silicon from the late 90s and early 2000s are being realized in real time in front of our eyes. But silicon has a ceiling: transistors can only get so small and we are already running into the limits. The next era will be the Age of Carbon, where organic reactions will dictate how we build, heal, and think.

     I hypothesize that in 50 years or less, almost everything in our lives will be touched by synthetic biology. It will be responsible for the materials you rely on everyday such as concrete, metal, and fabrics. It will produce the fuel for your car, the coffee flavors in your drink, and even do the computations on your phone. It will produce humans that can fight any infection, never age, and run on little sleep and food. In this post, I will outline how synthetic biology will touch everything that you encounter everyday.

     First, why biology? Mother nature has been refining biological systems for billions of years to do one thing: replicate. Along the way, new cell types formed, each one suited for a particular set of chemical reactions that optimize the cell for replication in its environment. To do this, they had to make everything ruthlessly efficient to outcompete their neighbors. They needed to replicate the fastest while using the least amount of resources and time. Then, cells began to work together in multicellular organisms, where each cell wasn’t looking out for itself, but for the whole organism. This allowed properties to emerge like specialization, cooperativity, and ultimately, intelligence. Think of everything mentioned above as tuning knobs that we, as humans and intelligent designers, can fiddle with to fit desired engineering design criteria. The hard part is becoming an intelligent designer. These cells are so complex that we only have a figment of an idea of what is happening inside of them and between them. We have only started to put pen to paper, wrapping our heads around what a cell actually looks like and what is inside. The book "Biology By the Numbers" and quotes like "A cell is a burrito" stunned the biology community and changed how we think of cells, and these were released as recently as 2015! These pieces transformed our idea of cells from sacs of water to highly organized and tightly packaged machines. With advances in AI and events like the virtual cell challenge, it seems like we are on the doorstep of understanding cells, we just need to reach out and open the door in the next ~15 years. Once understanding is reached and we can fully manipulate single cells and multicellular organisms, the sky is the limit in terms of our potential as a human race.

Making molecules

     The application that will come the soonest and is already here to a degree, is bioproduction of industrially relevant molecules. In 1976, venture capitalist Bob Swanson and biochemist Herb Boyer started Genetech, a company that puts pieces of DNA together and puts them into bacteria to produce insulin. While they struggled at first, they eventually were able to optimize the system in yeast and started the industry of biotechnology. The so-called “bioeconomy” more than doubled in the past 3 years ($25B in 2025) with the Ozempic craze, also produced by yeast, and is showing no signs of slowing down. While both of these examples are biologics, or protein/peptide medicines, cells can also make industrially relevant small molecules, or chemicals. They can do this by using protein machines called enzymes, which catalyze a specific chemical reaction, turning a reactant into a desired product. They can express multiple of these enzymes at once, carrying out multi-step chemical processes entirely in a single cell. While they are producing these molecules, they are also growing and dividing, producing more cells to make these chemicals. If all you have to do is put these cells in some nutrients and water, it can seem like you are almost getting free desired chemicals! Some examples of biologically sourced chemicals are citric and lactic acid as food additives, ethanol and butanol as fuels, and vitamin B12 to keep you healthy. These are just current applications that are already affecting your everyday life. Current research is being done to engineer cells to produce bio-acreleins, to replace petroleum derived ingredients in paints and even diapers, 1,4-butandiol which is used to make spandex and plastics, and even chocolate, coffee, eggs, milk, oils, meats, the list goes on! Imagine what we will be able to do with full understanding of the cell and all metabolic pathways. We could engineer them to do almost anything!

Materials

     While further from the present, exciting work is also being done in biologically produced materials. One example is in mycelium leather, where mushrooms are grown in industrial waste, like sawdust, and are combed flat to form a leather-like material. Adidas has a line of mycelium leather based shoes, Stella McCartney made a 2 piece set with it, and Hermés reimagined its classic Victoria travel bag with the material. Although I have heard it has had a tepid response, the technology will only get better. Another example of biology based material is in concrete. While we haven’t been able to produce concrete with cells (yet), there has been research into "self healing" concrete, in which dormant extremophile bacteria live in concrete (which has a pH similar to bleach), and are awoken once exposed to oxygen, which occurs when a crack in the concrete forms. Once activated, the bacteria eat calcium lactate, which was in the concrete mix, and use it to produce calcium carbonate, or limestone. This way, the bacteria are repairing cracks in the concrete as they form! This can increase the lifetime of structures and ease the stress on public works maintenance. Bacteria have also been engineered to produce 1,3-propanediol, which is a moisturizer, a solvent in cosmetics, and a key component of polymer fibers used in textiles and carpets. Trees have been edited to reduce the amount of lignin they make, which allows for cellulose molecules to be packed tighter, resulting in wood as strong as aluminum alloys used in airplanes. Again, these are just current examples, imagine what we will be able to do in 20 years. Dream big. I am talking about trees that grow fast and tall and produce wood stronger and lighter than steel. I am talking about cells growing you a house to your exact design specifications. Nothing is impossible. The future is bright for synthetic biology producing and optimizing materials we encounter in everyday life.

Computation

     So far, I have talked about biology being able to replicate and produce almost anything. However, once we have perfect control over the cell, things get really crazy: cells can be the basis of all computation. Let’s unpack this. Since this is mostly theoretical, let's get into some math. First, let’s compare energy that a GPU will take vs energy cells will take. The theoretical efficiency ceiling to flip a bit is $E = k_{B} \cdot T \cdot \ln(2)$, where $k_{B}$ is the Boltzmann constant. Current GPUs take 10^-11 joules to perform an operation, where cells take just 10^-20 (think an ATP molecule binding to something). Cells are astoundingly more energy efficient. Now let’s look at speed. Since cells rely on chemical kinetics to perform an operation, instead of GPUs which use electricity to do their computations, cells are about 10^6 slower. This is a ton slower and could be a problem for cellular computing. Additionally, cellular computation isn’t binary and deterministic like today’s computers, but is stochastic as molecules move around according to brownian motion. However, this isn’t a problem, as startups are already making GPUs that use stochastic signals instead of deterministic signals, and it shouldn’t be too much of a challenge to move this to measuring cell signals. The final nail in the coffin for silicon is the 3D layering that biology is capable of. Even though features on a silicon chip can be layered on top of each other, they can only get so close until the heat from the operations interferes with neighboring gates. Since cells are so efficient, they can be packed in tight. Let’s think about this in terms of a human brain. The brain can perform 10^18 operations per second, consuming 20 Watts. For silicon to replicate this amount of computation, it would need 20 Megawatts. Now this is assuming that each cell would give either an on or off signal according to its inputs. Let’s consider the case where there are multiple computations happening inside of each cell and the numbers are off the charts.

     One extra thing I want to mention, especially since AI is so prescient, is the idea of a mini neural network inside of a cell. In silicon, a neuron in a neural network is represented by $y = f\left(\sum_{i=1}^{n} (w_{i} \cdot x_{i} + b)\right)$. Where x are the inputs, w are the weights, b is the bias, and those terms are wrapped in an activation function. This is exactly what happens in a phosphorylation cascade inside of a cell. The inputs are the concentrations of the signaling molecules, the weights are the binding affinity of enzymes to those molecules, the bias is the basal activity of the enzymes, and the activation function is the sigmoid function common in living systems. In this way, we could have a mini neural network in each cell, communicating in a larger population of cells, able to spit out an answer. Even though the speed is still an issue, cells are doing thousands of computations at once, where a transistor can only do one. Taken all together, I am convinced that much further down the line, cells will be the basis of our computation.

Information Storage

     Another awesome trait about cells is the amount of information that they can pack into an incredibly small amount of space. Take humans for example; if you stretched out our DNA in just one of our cells, it would be about 2 meters long. Take the DNA from all the cells in our body and it would go to the moon and back. Another advantage of DNA as an information storage system is that it is base 4, not base 2 like modern computers, so it can code for information more densely. Due to this, some companies, like Twist Biosciences, have been exploring DNA as a form of information storage. Twist is a DNA synthesis company, so their dream is to take the information you want to store, synthesize the corresponding DNA sequence, store it somewhere physically, then take it out and sequence the DNA when the information needs to be accessed. This is a dream because DNA synthesis isn’t that fast, isn’t that cheap, and there are DNA sequences that are extremely hard to synthesize using current methods, limiting its use cases. Sequencing is also relatively expensive and slow for this application, on top of not being sensitive enough to reliably read every base of every DNA molecule. However, DNA sequencing has been outpacing Moore’s law for the past 20 years, but DNA synthesis is a real bottleneck and hasn’t had the same gains that DNA sequencing has flourished from. I have hope that this will be a realistic application of DNA technology soon.

Engineering organisms

     Finally, we get to how synthetic biology can engineer multicellular organisms to bring us into the future. Well there is the obvious application: solve aging, cure all diseases, etc…, but I dream even bigger. Do you remember in my post “How De-Extinction Paves the Way for Designer Humans” where I discuss how Colossus Biosciences may build designer animals for specific purposes like being cute or hunting enemies? (If not, you should give it a read. It’s shorter than this post don’t worry) Well the beginning of this has already started to happen. Mike Levin’s team out of Tufts has been messing around with limb regeneration (another application btw), and has made so-called anthrobots. These are clumps of tracheal cells that spin in circles, making more clumps of tracheal cells. Those clumps also start moving and make more! Multicellular synthetic Von Neumann machines. They found that when they put these anthrobots onto a monolayer of neuronal cells in a dish and made a scratch, the anthrobots would spontaneously repair the scratch! This work sets the precedent for living biological robots, living inside of us, repairing us as we are damaged. This was an incredible paper to read and I highly recommend you read it, even if you don’t have a strong science or biology background. This is just one example. Here more than anywhere, the sky is really the limit on how we can engineer synthetic organisms or existing organisms to improve human health or towards any design criteria.

     Of course the huge asterisk with all of this is how much we are able to understand about cellular behavior, and how much research we can do into these applications in the next 50 years. With current progress accelerating and NIH/NSF funding hopefully not getting nuked, I have high hopes that we will be living in the Age of Carbon very soon.