Innovations in biomimicry-based materials and techniques

Innovations in materials and techniques based on biomimicry are transforming construction engineering. Biomimicry is the discipline that studies nature's models, systems, and processes to emulate them in solving engineering problems. The term was popularized by Janine Benyus in Biomimicry: Innovation Inspired by Nature (William Morrow, 1997; ISBN 978-0060533229), although the practice predates the term: Heinz Isler's shell vaults in the 1950s were already inspired by leaf forms.

In construction, biomimicry is not about imitating natural forms for aesthetic purposes, but about understanding the functional principles that 3.8 billion years of evolution have optimized —structural efficiency with minimal material, thermal regulation without external energy, self-repair, hydrophobicity— and translating them into measurable technical solutions. The innovations described below are backed by scientific research published in peer-reviewed journals.

Concrete is the world's most widely used construction material (over 10 billion tonnes annually) and its main pathology is cracking, which allows water and aggressive agents to penetrate, accelerating reinforcement corrosion and reducing the structure's service life. Researcher Henk Jonkers at Delft University of Technology (Netherlands) developed a concrete that repairs itself using bacteria of the genus Bacillus.

The mechanism works as follows: bacterial spores and calcium lactate (nutrient) are encapsulated in expanded clay particles and incorporated into the concrete mix during batching. The spores remain dormant while the concrete is intact. When a crack appears, water penetrates and activates the spores: the bacteria germinate, metabolize the calcium lactate, and produce calcium carbonate (CaCO₃) that precipitates and seals the crack. The process can repair cracks up to 0.8 mm wide.

The foundational research was published in: Jonkers, H.M., Thijssen, A., Muyzer, G., Copuroglu, O., and Schlangen, E. (2010). "Application of bacteria as self-healing agent for the development of sustainable concrete." Ecological Engineering, 36(2), 230-235. DOI: 10.1016/j.ecoleng.2008.12.036. Subsequent research has extended the application to low-temperature marine environments (Palin, Wiktor, and Jonkers, 2017, Biomimetics, 2(3), 13; DOI: 10.3390/biomimetics2030013).

Macrotermes termites in Africa maintain their mounds at a constant temperature of approximately 31°C, despite outdoor temperatures ranging from 2°C at night to 40°C during the day. They achieve this through a network of ducts that exploit pressure and temperature differentials to generate convective airflows without any energy consumption.

Architect Mick Pearce, in collaboration with engineers Arup, applied this principle to the design of the Eastgate Centre in Harare (Zimbabwe), completed in 1996. The 31,000 m² building (shopping center and offices) has no conventional air conditioning system. Instead, a high thermal mass concrete structure absorbs heat during the day; at night, fans (the only mechanical component) draw cool outside air through the building to dissipate accumulated heat, "charging" the structure with coolness for the following day. Hot air is evacuated through rooftop chimneys.

According to data published by Arup, the Eastgate Centre consumes 35% less total energy than six comparable buildings with conventional HVAC in Harare. The capital cost saving was 10% by eliminating the air conditioning system. The building demonstrates that biomimetic passive ventilation is viable at commercial scale in hot climates.

Lotus plant leaves (Nelumbo nucifera) remain clean in muddy environments thanks to their superhydrophobic surface: micropapillae of 10-20 micrometers in diameter covered with wax nanotubes create a water contact angle greater than 150 degrees, so that droplets roll off carrying dirt particles with them. This phenomenon was scientifically described by botanists Wilhelm Barthlott and Christoph Neinhuis in 1997.

In construction, the lotus effect has been translated into facade coatings and paints that drastically reduce the need for cleaning and maintenance. The best-known product is Lotusan, a facade paint developed by Sto SE & Co. (Germany) that incorporates a microstructure similar to the lotus leaf. Field studies show that treated facades maintain their clean appearance for over a decade without washing, reducing water consumption and chemical detergents associated with building maintenance.

Another relevant application is Pilkington Activ self-cleaning glass, which combines a photocatalytic TiO₂ layer (which decomposes organic matter with ultraviolet light) with a hydrophilic surface that causes water to spread in a sheet, carrying away residues. This dual mechanism —photocatalysis plus hydrophilicity— reduces the frequency of window cleaning in high-rise buildings.

Bones are evolution-optimized composite materials: they combine stiffness (dense cortical bone) with lightness (porous trabecular bone), distributing material precisely where stresses demand it. The same principle is observed in the spicules of the glass sponge Euplectella aspergillum, whose silica lattice structure withstands remarkable mechanical loads with minimal material.

In construction, these principles are applied through topology optimization: algorithms that remove material from low-stress zones, generating organic forms similar to bone structures. Companies like Arup have used topology optimization combined with additive manufacturing (3D printing) to produce structural steel nodes weighing up to 75% less than conventional equivalents while maintaining the same load-bearing capacity. The MX3D pedestrian bridge project over the Oudezijds Achterburgwal canal in Amsterdam (2021) applies these principles.

Plant photosynthesis converts solar energy into chemical energy with modest efficiency but minimal infrastructure complexity. In construction, this principle translates into two innovation pathways:

Facade bioreactors: the BIQ House project in Hamburg (Germany, 2013), designed by Arup and SSC Strategic Science Consult for the International Building Exhibition (IBA), incorporated the world's first microalgae bioreactor facade. Laminated glass panels measuring 2.5 m by 0.7 m contain a microalgae culture that grows with sunlight, producing biomass for biogas generation while simultaneously providing dynamic shading (algae grow more with more sunlight, increasing shading when it is most needed). The panels also capture solar heat stored in a geothermal system.

Perovskite solar cells inspired by photosynthesis: although technically not direct biomimicry, perovskite cells replicate the principle of photon capture in thin layers, achieving efficiencies exceeding 25% in the laboratory with potentially much lower manufacturing costs than conventional silicon. Their integration into ventilated facades and semi-transparent glass represents one of the most promising frontiers of sustainable construction.

The main challenge of biomimicry in construction is scalability. Jonkers' self-healing concrete works in the laboratory and in prototypes, but its cost remains 2 to 4 times higher than conventional concrete. Superhydrophobic surfaces lose effectiveness with mechanical abrasion. Facade bioreactors require specialized maintenance.

However, the trend is clear: as the construction industry assumes more ambitious decarbonization targets and seeks to reduce long-term maintenance costs, biomimetic solutions are transitioning from academic curiosities to technically viable options. The combination of biomimicry with additive manufacturing, artificial intelligence for form optimization, and new bio-based materials is accelerating this transition.