(Im)possibility
During the first two weeks of the residency I had two important practical questions: could we synthesize or obtain at LEPABE nanoparticles that react (are attracted/repelled) to an electromagnetic field force?; could we synthesize or obtain at LEPABE that excite/absorb 445nm radiation and emit any other wavelength of the visible spectrum? Soon after I've understood that the nano4med research team level of commitment with the projects they had in hands, was total. Besides that the call for the artistic residence was clear: artists could only explore processes, materials and results developed by the lab teams. That meant it was impossible to do experiments that would fall out of the lab research scope that was in course. So, my initial intentions of exploring electromagnetism and ferrofluids as media to modulate matter were frustrated. Even with these constraints, there was the chance to run some adsorption experiments using vortex and ultrasounds technologies, available in the lab, to fixate respectively thioflavin and riboflavin molecules to triiron tetraoxid particles. (Figures 4 a, b and c) My intention was to produce particles that would be simultaneously fluorescent and moved by magnetic field forces. We didn’t succeed because the fixation didn’t happen. After this failed experience I decided to move forward without magnetic fields forces, and simply explore articulations between light and solutions of tioflavin, riboflavin and salt. (Imagem de 9 de fevereiro de 2022).
Initial objectives
1. Build a mediation system that makes it possible to affect – human perception at a human scale – the dynamics that occur at the nanoscale in the interaction and manipulation of nanomaterials.
2. Model nanomaterials – controlling the positioning, organization, and appearance of nanoparticles – through electromagnetism and/or coherent light controlled by audio signals.
3. Study the propagation of electromagnetic waves in heterogeneous media and explore the aesthetic potential of modeling the appearance of light and the chromatic sensation produced by the interaction of coherent light and electromagnetic fields with colloids.
Areas of study
I wanted to investigate the incidence of laser light on solutions, colloids, and suspensions while exploring the combinatorial possibilities of ferrofluids in heterogeneous media. As such, three areas of study were methodologically considered in strict articulation:
1. Dimension of quantum dots (Figure 1);
2. Mixture (solution, colloid, suspension) (Figure 2);
3. Radiation and electromagnetic field.
My initial proposal also considered:
1. An artistic research process anchored in the development of an innovative artistic research field that uses nanotechnology laboratory resources, materials, and techniques for artistic and aesthetic purposes;
2. Expansion of convergence points that enhance the usefulness and practical counterpart of aesthetic and artistic formalization processes in the optimization of scientific research processes and protocols.
From nano to molecular
At the time of my residence, the beginning of March 2022, the lab researchers were using Thioflavin T (a fluorophore that binds to proteins/peptides with a beta-sheet secondary structure), and vitamin B12 (a natural molecule that has therapeutic potential to treat neurological diseases and cancer). It was common to see in the lab computer monitors two-dimensional cartesian spectrograms representing relative intensities (vertical axis) of different wavelengths (horizontal axis) from part of the electromagnetic spectrum. Some of these graphics showed two lines: one representing the absorption and another the emission of a given nanoparticle or molecule. These graphics were produced by the above mentioned BioTek Synergy Neo2. My interest about light made me deepen the study on photoluminescence , in particular fluorescence and phosphorescence. As the Neo2 worked with a xenon lamp combined with a monochromator (filter that absorbs all wavelengths except a specific one) I considered that there was a huge waste of energy because almost of it was absorbed by the filter, this fact justified my option to use a coherent source of light – laser.
During this research I came across the article “Magnetron-sputtered Polytetrafluoroethylene-stabilized Silver Nanoisland Surface for Surface-Enhanced Fluorescence” [1] where I found an image (Figure 3) that depicts the absorption and fluorescence spectrum of riboflavin solution in water. The image also depicted the excitation wavelength and the chemical formula of the molecule (rioboflavin). This image was the key, the trigger, of my work. A phenomena that I knew since I was a child – fluorescence under UV light inside discotheques and clubs – was clearly explained with a single image. From the graphic observation I understood that there’s a very small amount of matter, much smaller than a nano dot, a molecule that is able to be excited with photons oscillating with a certain frequency and immediately emits photons oscillating at a lower frequency. Basically a small amount of matter that under blue light emits green light. And the best was that this molecule is natural [2].
I immediately bought riboflavin to make my first tests.
Riboflavin is excited with photons that oscillate at frequencies close to 673 THz and emits photons that oscillate at approximately 545 THz – wavelengths of 445 and 550 nm, respectively. I conclude that riboflavin – by reducing the frequency of oscillation of photons – reduced the velocity at which they oscillate. It’s known that the speed of light is constant, but also that an oscillating particle has variable velocity depending on the oscillation frequency. As velocity implies acceleration, the reduction of a particle velocity implies its slow-down. I discussed these ideas with Manuel Melle-Franco, a chemical physicist, principal researcher at Aveiro University Institute of Materials. He shortly instructed me that for every three photons absorbed by a riboflavin molecule one is returned, oscillating at a lower frequency. It is a phenomenon of energy re-emission, frequency reduction and oscillation speed reduction. This conclusion grounded the title I gave to the artwork: (Des)aceleração.
It’s worth to mention that before I found de above mentioned article and closed my choice for riboflavin, I studied other possibilities that were also no available at Lepabe like antibody dyes fluorophores for microscopy and imaging[3] or GmKate fluorescent protein[4] .
Custom DAC to ILDA interface
The proper operation of each one of the two laser scanners and three laser lights, that integrates one laser show system, requires a parallel transmission of at least five analogue control signals. ILDA[6] is known as an analog signal transmission protocol to control laser light systems from a computer or a controller. As I am experienced in artistic computer programming to calculate, generate, process and control digital audio signals that have to be converted to analogue signals in order to be heard, I decided to control the laser using DSP (Digital Signal Processing).
Computer control signals are serial, therefore they have to be converted to parallel analog systems via a DAC – digital to analog converters. A multi channel audio card converts multiple digital (discrete) audio signals to multiple analogue (continuous) ones. The standard output connectors from audio cards are independent TRS female connectors (with three contact points each) and the standard ILDA connector on the laser show system has 25 pins (each one is one connector). In order to send the analogue signals from the DAC to the laser show system I had to build a custom interface following Ted Davis wiring diagram(Figure 7)[7]. (Figures 8 a, b, c and d).
Laser control
The laser show system used in this residency is a Class IV laser that can be hazardous for human eyes and skin. As I wanted to use the laser to excite riboflavin molecules, diluted in water as a solution contained inside petri boxes, and because petri boxes are made of glass and glass is highly reflective material I needed an absolute precise control over the laser beam. In a total controlled environment (my studio basement), without any reflective material, I started developing original software to control the laser. I’m a geometer for a long time and geometry deals space properties – point, line, plane, distance, shape, size, or relative position of figures – therefore I started to program a software that could compute digital signals that, after converted to analogue ones, allowed me to draw precise geometric shapes – circles, triangles and squares. These exercises gave me the skill to control the laser beam in a very precise way. (Figures 9 a, b, c, d, e and f).
The artwork (Des)Aceleração began as a submission I made in early 2022 for a 2SMART artistic residency that took place in March and April of the same year at Nano4Med, LEPABE – Laboratory for Process Engineering, Environment, Biotechnology, and Energy. I chose this excellent nanotechnology research lab due to my intrinsic motivation to use and explore light as an expressive artistic medium. In this lab, I could explore the interaction of light with nanoparticles and affect humans with the ways that light affects and is affected by matter at the nanoscale.
Light has been studied and used since immemorial times. Light scattering, reflection, and absorption effects are felt in and by nature, and explored by humans, from the arts to the sciences. In order to perceive the events that occur at the nanoscale, we need Transmission Electron Microscopes (TEM) that function as prostheses of the human sense of vision (Human->TEM->Nanomaterial). For this residency, I intended to produce research that cuts out the prostheses and reverses the aforementioned direction, affecting human visual sensations (Nanomaterial->Laser Light->Human) with events that result from the interaction of manipulated electromagnetic radiation (coherent light – laser) with nanomaterials.
The senses of hearing and vision have always coexisted in human beings. The phenomenon of seeing and hearing simultaneously is called auditory-visual integration. The research I intended to develop initially in the residency would result in a perceptual object composed of nanoparticles in a heterogeneous environment whose appearance – shape, volume and chromatic sensation – would be modeled by audible audio signals that simultaneously would control electromagnetic fields and laser beams.
Methodology
A hybrid top-down and bottom-up approach was used. From top to bottom, the methodology was determined by the intentions expressed above. From the base to the top, the methodology was determined by the process of familiarization, approximation, knowledge, and recognition of the materials, techniques, tools, and instruments of Nano4Med, so that the conceptualization of the work(s) was formalized during the laboratory experience.
Site specificity
This artistic residency culminated with a public individual exhibition at the Library of Engineering Faculty of Porto University. The space is a long parallelepiped and only four of its six sides (floor, ceiling and north and south walls) are closed. The west face of this volume is totally filled with windows that have the full height of the space. The east face of the volume is open to the foyer and reception of the library. (Figures 11 a and b) My experiment needed a totally controlled light environment because the riboflavin molecules are excited, as I wrote above, with 450nm wavelengths and both, natural light – that enters by the library west wall – and artificial light – that comes from the foyer – are composed by this wavelength as well. As my experiment worked with two specific wavelengths – 445nm from the laser and 550nm emitted by the riboflavin molecules – I needed to be sure that no other light source would emit this wavelength and contaminate my experience. Simultaneously I needed some light for the visitors to understand and navigate the space. My childhood memories of photography dark rooms made me remember what spaces illuminated with red light felt like. Also, red light doesn’t have the wavelengths absorbed and emitted by the riboflavin molecules so I decided that red, as ambient light, would be the third colour used in the experiment. I had at my disposal the most powerful light source known – the sun – which energy propagates inside the library through its big windows on the west wall. I used a low pass filter, that blocked all wavelengths below 640 nm, in all windows and a black clothing that blocked all visible wavelengths coming from the artificial lights on the foyer. As a “coincidence” the experiment was done with the primary light colours: red, green and blue; red from the filtered sunlight, green emitted by the riboflavin and blue emitted from the laser. It is worth mentioning that the red filter on the windows allowed my experiment to dialogue with the exterior space, including in the experiment itself all the movements that occurred outside. (Figure 12).
Figure 12: Natural light filtered with lowpass filter and blue laser exciting solution of riboflavin.
Composition
The final composition of this artistic experiment was done in the exhibition space once all the conditions and resources were gathered in the same place. One of the most common strategies in my creative process is the subversion of mediums to create new ones. In all my artistic experiences I end up transforming and subverting the original function of mediums by creating new thoughts, new ideas and new functions for existing mediums. In (des)aceleração it wasn’t different: the exhibition venue as become part of exhibit object itself; the riboflavin that as a biological function in live beings, worked as a way to deaccelerate the speed of photons that oscillate at frequencies with 450 nm wavelength; the petri dishes which laboratory function is to isolate bacteria growth, were used as recipient, as a light scattering medium and as “pixel”; the library vertical plinths – normally used for fixing images on their faces and as space dividers, were laid down and united – became a single volume that was used as a base that justified the petri plates placement; the multichannel sound card designed to convert digital audio signals into analogue ones was used control respectively the laser galvos and the brightness of the laser light.
The laser light movement through the petri boxes was inspired in some diagrammatic representations of the riboflavin molecule visual models, special in the chemical bonds between its atoms (Figure 13). The placement of the petri boxes made me remember the long rectangular matrix from the classic game Tetris therefore, when I was programming the software that simultaneously calculates the laser light movement and the sound synthesis, I decided to use as a basis for the sound composition the Tetris theme notes – a major scale with chromatic change on the fifth grade.
The laser movements and the sound diffusion are synchronically operated by an original algorithm that, using stochastic and probabilistic processes, calculates, in real time, the digital signals that once converted to analogue ones control the galvos, the lasers brightness and the loudspeakers. What can be heard in the installation results from the combination of two sound synthesis processes – one additive and another subtractive. The additive process generates a new tone every time the laser focuses on one petri plate (one iteration). This first process adds six digital audio signals generated by six sawtooth antialiased oscillators. One oscillator is set , at each iteration, randomly with one of the fundamental frequencies of the notes that constitutes the major Tetris theme scale. The remaining sawtooth oscillators are simultaneously set with the first five harmonics of the frequency of the first oscillator. Once the laser focuses on a particular petri box there’s a vibrato that affects both the sound and the laser and decays with time. The subtractive process consists of a white noise generator whose signal is filtered through a low pass filter whose cut off frequency is the fundamental frequency of the sawtooth wave generator used in the above mentioned additive process. The resulting filtered digital audio signal is added with two sine waves, one oscillating at the same fundamental frequency and the other oscillating as the first harmonic of the former one. The sound is spatialized with two sound channels, reinforcing the movement of the laser light in the space.
This work is a result of project 2SMART, engineered Smart materials for Smart citizens, with reference
NORTE-01-0145-FEDER-000054, supported by Norte Portugal Regional Operational Programme (NORTE 2020),
under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).
Figure 1: Size dependent optical properties of quantum dots. Source: https://serc.carleton.edu/msu_nanotech/nano_intro.html
Residence
Even if my starting goal was to explore nano materials, I ended up exploring a much smaller dimension – working with molecules and therefore experimenting how coherent light interacts (affects and is affected) with common molecules.
My first sessions at the lab consisted of guided tours where the lab researchers gave me an overview of the research projects they were working on. These sessions allowed me to observe the technologies, tools, instruments and methods they were using to execute their studies.
From all the tools used at Nano4med, one triggered my interest and curiosity – BioTek Synergy Neo2 Hybrid Multimode Reader – by the following three main reasons:
1. this multimode microplate reader also worked as a prosthesis – extension of the human vision to phenomena that occur at molecular and nanoscale in very short time intervals like picoseconds and nanoseconds;
2. the microplate reader used light with different wavelengths and laser light as a medium for spectroscopic analyses of interactions between molecules – time-resolved fluorescence spectroscopy;
3. the microplate reader worked for the lab researchers as a black box, because they never could directly observe what was going on inside the box, the output of the reader is a cartesian two dimensional graph – a spectrogram.
As I wanted to work with laser light, and to counteract the prostheses and black box effect, the existence of BioTek Synergy Neo2 just reinforced my initial objective of building an artistic system that makes visible to the naked human eye dynamics that occur at the nanoscale. Simultaneously, due to my two decades interest in objectiles, I was studying possibilities of controlling and organising nanomaterials. I considered the crystallisation phenomena as a strategy for structural growth of elements based on nanoparticles local interactions triggered by an external medium like laser light and/or electromagnetism. Another possibility I was interested in was to use iron nanoparticles (ferrofluid) and electromagnetism as medium to modulate matter in time.
Cups to petri boxes
The first recipients I used in the first lab experiences to contain the solutions were common lab measuring cylindrical glass cups. (Imagem de 9 de fevereiro de 2022) The cups were totally ok for testing but the printed graduated scale on their sides added a layer of information, a semantic layer that was useless in the artistic system I intended to construct – the graduated scale was noise. I looked for other transparent recipients in the lab without graduated scale or other printed stuff and I immediately considered using test tubes. Their use implies some kind of support to hold them standing therefore, after a short period of reflective practice, I conclude that the support was noise as well. Then, I remembered the amazing Artificial Paradises[5] exhibit by my dear friend Leah Xie, integrated in her Chemical Garden Project,that I had seen 3 years earlier in Shanghai, where Xie used petri boxes as recipients for her compositions. Her work had such a powerful impact in my past experience that I decided to pay her and her work a tribute, therefore I decided to use petri boxes as recipients for the riboflavin solution and place them following an organisation that resembled the one thought by Xie: a flat ortogonal grid formed by columns/rows of petri boxes pristinely aligned. (Figure 5) (Figure 6 a and b).
Accident
After entering the safe zone of accurately controlling the laser beam with custom software and custom interface I started to test the combination of the laser light and riboflavin solution contained in a petri box. Besides having achieved the result I was expecting – green light emission using a blue light source –, accidentally I was surprised with an event with high aesthetically value for me: when the laser beam focused on the glass of the petri plate, it was refracted, reflected and scattered and projected on my studio walls in totally unexpected ways. (Figures 10 a, b, c, d). I was so pleased with the beauty of those scattered light projections that I decided to include these accidental situations in the final artistic experience.
[6] Abbreviation of "International Laser Display Association”, an association of laserists.
[1] Magnetron-Sputtered Polytetrafluoroethylene-Stabilized Silver Nanoisland Surface for Surface-Enhanced Fluorescence
[2] Besides the article referred in the previous note, I also studied the the photoluminescence phenomena in the following sources: The Light Spectrum and its Relationship with Fluorescence and Vio Dye Fluorophores or Molecular Mechanism of a Green-Shifted, pH-Dependent Red Fluorescent Protein mKate Variant