From: mk_thisisit
The creation and sustenance of human brain organoids represent a groundbreaking advancement in biotechnology, enabling the development of biological processors from living cells [00:00:01]. Final Spark, a Swiss biocomputing startup founded in 2014, is notable as the world’s first to build a living processor from living neurons [00:01:03]. This approach aims to combine the computing power of traditional computers with the efficiency of the human brain [00:01:15].
What is a Human Brain Organoid?
A human brain organoid is essentially a small fragment of nervous tissue [00:01:26]. It is composed of neurons derived from human cells [00:01:31]. While the concept of human brain organoids is not entirely new, with many researchers worldwide working on them [00:02:08], Final Spark’s unique contribution lies in using them for computing purposes [00:02:26]. Functionally, these organoids are designed to resemble the fetal brain [00:05:32].
Creation Process
The process begins with obtaining human cells:
- Cell Sourcing Companies specializing in cell production provide pluripotent stem cells [00:03:04].
- Reprogramming These stem cells are typically derived from fibroblasts (skin cells) that have been reprogrammed to a state of pluripotency [00:03:10]. Pluripotency means they have the ability to become any type of cell [00:03:22].
- Differentiation Specific methods are used to differentiate these pluripotent stem cells into neurons [00:03:36]. This involves adding particular molecules to the culture medium, signaling the cells to transform into neurons, astrocytes, and other brain cell types [00:03:51].
- 3D Structure Formation The cells are grown on special plates that facilitate the formation of a three-dimensional structure [00:00:07], [00:04:55]. Over time, these cells reorganize themselves into structures that resemble parts of the brain [00:05:19].
Sustaining Life
Keeping the organoids alive is a significant challenge [00:00:36], as initially, they would die within a few hours [00:14:09]. Now, they can be maintained for weeks, even up to almost three years [00:07:06].
Key elements for sustaining brain organoids include:
- Culture Medium A special pinkish culture medium provides essential nutrients for their survival [00:05:51].
- Flow System A continuous flow system, managed by tubes and a pump, ensures the growing medium circulates under the organoid at rates like 30-50 microliters per minute [00:06:23].
- Controlled Environment Organoids are kept in an incubator with precise conditions, including a controlled atmosphere to ensure sufficient oxygen [00:06:44].
- Temperature Regulation The temperature inside the incubator is maintained at exactly 37 degrees Celsius, mirroring the human body’s temperature [00:06:48].
- Orbital Shaker Some organoids are placed on an orbital shaker, which helps nutrients and oxygen to penetrate the organoid more effectively [00:05:35].
Connecting to a Neural Platform
To facilitate computation, organoids are placed on a multi-electrode array (MEA) [00:07:17]. The organoid is positioned directly on the electrodes to record its activity [00:07:22]. A membrane with a hole in the middle, referred to as “confetti,” assists in precisely positioning the organoid in the center and helps reduce system noise [00:08:39].
Energy Efficiency and Purpose
The primary motivation for developing biological processors is their remarkable energy efficiency compared to artificial neural networks [00:09:50]. A simulation of 100 artificial neurons can consume several kilowatts of power, whereas the human brain, with 86 billion neurons, requires only 20 watts [00:10:01]. This significant difference in energy consumption makes biocomputing a promising path for advanced artificial intelligence calculations [00:17:10].
The ability to record neural activity from these organoids, as demonstrated by observable “bursts” of activity suggesting communication between neurons, was a key breakthrough [00:00:30], [00:12:28]. Researchers aim to induce specific behaviors, which they refer to as learning, often using substances like dopamine as a reward mechanism to encourage desired actions from the brain organoid [00:13:19].
Ethical Considerations
The ethical implications of using living human neurons for computational purposes are recognized as a serious concern [00:00:44], [00:14:19]. Final Spark actively engages with universities and ethics experts, attending conferences to present their work and allow those knowledgeable in the field to consider the societal implications [00:14:57]. While rat cells could potentially be used for computations, human cells are preferred due to the potential for therapeutic applications that could directly benefit people [00:15:41].