A biomimetic smell sensor | Johannes Bintinger | TEDxKlagenfurt

Summary

This script explores building a handheld “tricorder” inspired by Star Trek that diagnoses by smelling — like dogs detecting disease in exhaled breath. It explains olfaction: odorant molecules, binding proteins, combinatorial coding, and neural signaling. The talk contrasts bulky instruments (MRI, mass spectrometers) with compact sensors (chemiresistors, graphene transistors) and describes biomimetic strategies using odorant-binding proteins and receptors to transduce molecular events into electronic signals. Challenges include achieving specificity, interfacing gas, liquid and solid phases, and creating stable membrane-embedded receptors. The goal: a portable device for medical diagnostics, food safety, and environmental monitoring — a real-world tricorder.

Takeaways

• 🚀 The talk draws inspiration from Star Trek’s tricorder, a fictional device capable of non-invasive, real-time diagnostics and environmental scans.
• 🧠 The speaker aims to explore how such a tricorder could become reality by merging biology, chemistry, physics, and electronics.
• 📱 Technological evolution shows how miniaturization (e.g., hard drives shrinking to coin size) is crucial for innovation and portability.
• 👃 The key concept involves replicating the human sense of smell, which relies on olfactory receptors that detect and translate odor molecules into electrical signals.
• 🔬 Smelling is a complex biological process that converts gas-phase molecules into neural signals through receptors, binding proteins, and ion channels.
• 🧩 Humans have about 300 olfactory receptors but can distinguish around 50,000 odors due to combinatorial coding—each scent activates unique receptor patterns like a QR code.
• 🧪 Chemically, even minor molecular changes (like adding one carbon atom) can drastically alter a substance’s smell, highlighting the sensitivity of olfactory detection.
• ⚙️ Technologies such as spectroscopy and mass spectrometry can analyze molecules but are too large for handheld use, motivating the need for smaller sensing devices.
• 💡 Bioelectronics and biomimetic approaches can help create artificial noses by integrating biological sensing mechanisms with materials like graphene for high sensitivity and conductivity.
• 🌿 Odorant-binding proteins serve as molecular shuttles that transfer odor molecules to receptors, and their conformational changes can generate measurable electronic signals.
• 🧬 The ‘holy grail’ of smell sensing involves embedding actual olfactory receptors in artificial membranes to mimic nature’s amplification and sensitivity.
• 🌊 Developing a smell sensor faces the ‘three-phase challenge’—integrating gas, liquid, and solid phases while maintaining electronic stability in wet environments.
• 💻 The invention of the transistor serves as a metaphor for early-stage innovation: small beginnings can lead to transformative technologies with massive global impact.
• 🩺 The ultimate goal is to build a functional medical tricorder for applications like disease diagnostics, food quality control, and environmental monitoring.
• 🖖 The talk concludes with a nod to Spock’s iconic phrase—'Smell is fascinating'—celebrating the wonder of merging science fiction with scientific discovery.

Q & A

What is the main focus of the talk in the transcript?

The main focus of the talk is on developing a medical tricorder, inspired by Star Trek, that can detect and analyze smells, using a combination of biology, chemistry, electronics, and physics.

What scientific breakthrough in olfaction was mentioned in the transcript?

The scientific breakthrough mentioned is the discovery by Richard Axel and Linda Buck, who received the Nobel Prize in 2004 for their work on the molecular mechanisms of smell, specifically how odorant molecules interact with receptors to create smell patterns.

What are odorant binding proteins, and why are they important in the development of smell sensors?

Odorant binding proteins are proteins that help shuttle odor molecules to receptors. They are crucial for creating a working smell sensor because they facilitate the transfer of odor molecules to receptors, which are essential for detecting smells in a sensor system.

How does a biological olfactory system differ from human-made smell sensors?

Biological olfactory systems are highly sophisticated, capable of differentiating thousands of odor molecules based on their size, structure, and functional groups. In contrast, human-made sensors are currently limited in their ability to match the specificity and complexity of the biological system.

What challenge does the speaker mention when trying to combine biology and electronics in a smell sensor?

The challenge is interfacing the three phases—gas, liquid, and solid—in a single device, and successfully combining complex biological systems with electronics. This requires overcoming issues related to keeping biological systems stable within a device and ensuring they function properly with electronic components.

Why is graphene considered a useful material for creating smell sensors?

Graphene is considered useful because it is lightweight, strong, biocompatible, and semiconducting. Its unique properties make it an ideal candidate for building sensors, especially when combined with biological elements like odorant binding proteins to detect smells.

What role does combinatorial coding play in the process of smelling?

Combinatorial coding allows the brain to interpret a vast array of smells using just about 300 olfactory receptors. The process involves combining signals from multiple receptors, each triggered by different odor molecules, to create a unique pattern that corresponds to a specific smell.

What is the 'three-phase challenge' in the context of creating a smell sensor?

The 'three-phase challenge' refers to the difficulty of combining and interfacing three different phases—gas (odor molecules), liquid (aqueous environment in biological systems), and solid (electronic components)—within a smell sensor device.

What is the significance of the first transistor in relation to smell sensors?

The first transistor, though not powerful or efficient at the time, was a revolutionary concept that laid the foundation for future developments in electronics. The speaker draws a parallel between this innovation and the current stage of smell sensor development, suggesting that we are at a similar turning point in this field.

How do mass spectrometry and infrared spectroscopy relate to smell sensing technology?

Both mass spectrometry and infrared spectroscopy are techniques used to analyze molecules based on their physical properties. However, these tools are large and not suitable for handheld devices. The speaker suggests that smaller, more specialized sensors based on these principles could be used in portable smell sensing technologies.