Friday 28th of May. Yoonha Kim and I head to Adlershof, a suburban campus of the Humboldt University of Berlin which is home to the Institute of Physics. Mohammad Fardin Gholami, our colleague from the cluster Matters of Activity, is happy to show us his working place, in the lab for macromolecular physics of Jürgen P. Rabe. Together we are preparing a VR installation for the exhibition “Stretching Materialities.” The project name of this work is “Virtual Sensing Knife.” It is a speculative simulation of the Sensing Knife — which is itself speculation between physics and neurosurgery.
The Sensing Knife is a project initiated by Prof. Rabe and later expanded by Fardin: the idea is to turn the sensitive probe of an atomic force microscope (AFM) into a neurosurgical tool that would “sense the brain material as it also can cut through it.” In order to further explore this idea and the imaginary that it encompasses, I am developing with a small team a VR installation which is bringing the visitors to encounter brain tissues at the level of the cell, and experience the boundary between zones of different densities (the typical case study in neurosurgery is the ablation of a tumor).
The coming together of a team of anthropologists, designers, and scientists has brought the project to unexpected paths. The aim of today is to “listen to a neuron” with one of the AFMs — an idea that came to Fardin during a visit of the sound designer Nico Espinoza.
Fardin has just received a few samples of HT22 cells from the team of Thomas Picht at the department of neurosurgery of the University Hospital of the Charité. Originally collected from a mouse’s hippocampus, they are multiplying and freely floating within a pinkish solution that nurtures them – whereby healthy cells actually interact and adhere to the Petri dish's inner surface. In this experiment, we are aiming to come to touch and listen, “as if with a stethoscope,” to an individual living neuron. The cells keep on floating, for now, maybe aware of our plans, perhaps already oblivious of their previous form of life and the act of scientific violence that has sent them to swim freely again. In a comment to an earlier draft of this text, Fardin wrote: “they are sure alive, their perception of environment might change as we perturb it with an oscillating probe...that’s exciting for me to think, I like to think that they are aware of mechanical perturbations surrounding them. «
The AFM sits in a box that isolates it acoustically from the outside world. This machine is constituted of two parts: one inverted optical microscope, on the right, makes it possible to adjust and control the action of the AFM, on the left. The AFM stands on three legs above the sample, which is moved underneath. The AFM has been invented in 1986, and the technology is in constant development ever since (see Dufrêne & al. 2017). The device is built around a swappable microcantilever often made of silicon dioxide, probably one of the thinnest, finest, and most sensitive human manufactured measuring artifacts. It is used to scan objects whose size is so minuscule that they are impossible to see with visible light — because the wavelengths of visible light are literally too large to interact with such entities. The originality of this technique is to bring a sensing needle into close contact. In the realm of physics, as Karen Barad reminds us, there isn’t any actual “touch” but only force fields: “The reason the desk feels solid, or the cat’s coat feels soft, or we can (even) hold coffee cups and one another’s hands, is an effect of electromagnetic repulsion. All we really ever feel is the electromagnetic force, not the other whose touch we seek. (…) Electromagnetic repulsion: negatively charged particles communicating at a distance push each other away.” (2012, 209)
Rotating knobs, Fardin is controlling the position of the tip of the cantilever on the microscope. The first generations of AFM were actually probing the surface of the materials by scanning and touching them. “We were destroying a lot of what we were touching” – the voice of Prof. Rabe resonates in my head as I am writing these lines. He has presented several times already this technology to the team and told us a few stories that link him, his lab, corporations, and some lucky students who became millionaires by developing the next generations of these costly machines. After destroying many of their objects of study, the physicists adjusted the mode of operation of the machine: the AFM now conducts its scan by hovering directly above the material, rather than touching them, feeling the repulsion and attraction fields and figuring out the resistance and elasticity. The cantilever oscillates and the scanning is effectively produced by figuring out the perturbation of this baseline frequency. However, the researchers also used it to manipulate protein single ribbons, “blow” circular protein into perfect loops or carve their initials on the surface of cells. This is how Jürgen Rabe came up with the idea of using it as a blade to perform surgery at the level of the cell — a surgical cut which would not harm the organism but only elegantly separate matter and let it bind and cohere again almost immediately together through its inherent activity (see collective article 2021 on the “informed cut”). Of course, the professor is perfectly aware that this is an overly ambitious project, and he sets it into the longer-term using a grand historical backdrop: “it took 15 years for the American to land on the moon”, he says with a smile when someone raises the question of the feasibility of this project.
Meanwhile, Fardin is observing the cells within the pinkish solution – a few drops of the pink solution were within a plastic Petri dish containing the cells. Fardin points to a grid with a red point on the screen: the red point isn’t centered and keeps moving erratically — the vibration frequency of the cantilever is picked up using the reflection of a laser, and the red point indicates the alignment of the laser with the photodiode (sensor to detect the reflected laser). The restless motion signifies that there is a micro perturbation impacting the reading of the movements of the cantilever. He checks out the scene directly using the optical microscope: “That cell is hanging to the cantilever!” he says, showing us the culprit. Joining to his words his whole body, he mimicks the clinging as if he was hanging his body to a bar (or a cliff). His understanding of the situation is embodied, he is entering into correspondence with both the AFM and the cell by propelling himself onto the microscopic stage.
As Natasha Myers has shown in her book Rendering Life Molecular (2015), “molecular modelers’ responsive bodies are attuned to subtle molecular forces and affinities; they hitch rides on the molecular movements they model and allow these intricate forms to inflect their gestures and affects.” (Myers and Dumit 2011, 240) A leading brand of AFM has chosen for name “Nanosurf”: that name brings me to picture the macromolecular physicists and AFM operators riding the matters’ wave as they scan their reliefs, sliding on top of magnetic force fields.
Like a blind person with a stick, the researcher is probing the material which lies beyond the scope of their perception, their senses augmented by information inputs that can take multiple shapes — 2D or 3D visualizations. Their prosthetic crystalline fingers, sensing matter down the scale, are sometimes portrayed as submarines sounding the ocean’s floor. The perceptive body of the researchers goes down the scale with their instruments, with their hearts and souls: “Modelers transduce these affects through their body-work and propagate these gestures through performative articulations that excite others into action.” (Myers and Dumit 2011, 241)
The company MicroMotion, one of the manufacturers of the cantilevers, has used the submarine as a key visual on its promotional material sent in the expensive boxes of cantilevers (“The content of this box costs 4.500 euros”, as a label reminds the lab visitors in bold characters on a transparent box the size of an old Nintendo game cartridge). One of these posters was adorning the wall of the lab on my previous visit. The imaginary of the immersion “down the scale”, as the title has it, brings back the dreams of the 19th-century explorers and their taxonomic enterprises, the discovery of unknown territories: “you never know what you might catch”. Moreover, it points again in the direction of the immersion of the experimenter into a fluid medium that they're experiencing through their sensory immersion, sounding the bottom floor of matter. Calling it a practical “pun", Helmreich reflects on the etymology of the verb “to sound”: “sound as fathoming has its etymological moorings in the Old English sund, "sea," whereas sound as vibration reaches back to Old English swinn, "melody”. (2007, 624)
©MoA & Itaru Yasuda, Virtual Sensing Knife, excerpt from research process
Not unlike Stefan Helmreich in his astonishingly immersive text “An anthropologist underwater” (ibid.), I have been dreaming with a small team of transposing the machinic sensorial immersion of AFM into a VR installation. “How have underwater soundscapes come into audibility for humans? Devices that permit listening across different media-from water over into air environments (like the inside of the sub)-are key,” writes Helmreich (ibid. 624). In the project "Virtual Sensing Knife”, Fardin, Yoonha, and I are working with a sound designer and an interaction programmer to produce a simulation of Prof. Rabe’s vision for a knife that senses and cuts, down at the level of the cell. This multimodal anthropological project proceeds as an inventive and iterative ’sounding‘ of the potential intra-actions between physics, design, and neurosurgery. We are exploring techno-poetic paths to relate to the more-and-less-human status of neuronal tissues. That endeavor broadly encompasses Helmreich’s “immersive soundscape, submarine cyborg and transductive ethnography”. “Each group of neurons, any cut or isolated circuit can be thought of as a subject with relation to the rest” (Dumit 2006, see also 2014) — this immersive field trip may provide an understanding of the profoundly alien agency of the neuron: The neuron is both a figure of the convertibility of humans and machines and an illustration of the hypo-subject embedded into the microbiome context (see Helmreich 2015).
Here is a verbatim of my oral attempt to explicit that prototype and our research project during a presentation last week at the cluster:
“This is the prototype we have, which is the work of Itaru and Nico. What you’re looking at is the first step of this iterative process. We had to decide what to do first. (…) We decided to first work on just this kind of blob of virtual material. This virtual material would be probed or sounded with a handheld device, which makes it possible to encounter one type of material. The sound that you hear is triggered, modified, and changed by the way you interact with the matter. (…) There is always sound in the background, which is the vibration of the oscilloscope of the sensing knife, which is trying to touch something that is at the bottom of the scale. The crispy noise that you can hear are perturbations, in form of information of the neuron, what is happening. The next step is to create different blobs with different types of sounds, and then of course the exciting part of this working with different materials that are colliding together. Understand what is happening when you have different digital materials that are closely intertwined together and that has a boundary. The idea behind that is to make this invisible boundary sensible and to make it tangible in different ways, not only by touching. (…) But I wanted to hint at this very old text on VR by Michael Heim explaining that VR can be a way to “train and enhance receptivity.” And a strategy to induce a more receptive atmosphere is exactly what we’re working on and having empathy for other beings. We’re developing a way to relate to other entities, non-human entities like the cell of a brain for example. “
I would like to thank Yoonha Kim, Fardin Gholami and Anne Delle for their comments!