Intimate wear is one of apparel’s most technically demanding categories. Bras, underwear, shapewear, maternity garments and performance base layers must balance flexibility, recovery, support, softness and durability all while remaining comfortable against the skin for extended periods.

Delivering this combination of qualities usually requires a complex mix of materials. A single garment may combine natural or synthetic textiles with elastane, foams, adhesives, elastic bands, plastic hardware and metal components. Although each element performs a specific function, bringing so many different materials together can make the finished garment difficult to separate, recycle or manage responsibly after use.

As part of her thesis research, textile designer and researcher Shlomit Ariel of CodedMatter Lab, under the supervision of Yoav Sterman, explored another possible approach using Balena’s BioCir® Flex: printing auxetic structures directly onto natural-fibre textiles to introduce stretch, support and recovery precisely where they are needed.

The result of Shlomit’s research is Gaia, a conceptual nursing bra and underwear set that offers a tangible vision for how intimate garments could be designed with performance, material health and end-of-life considerations in mind from the very beginning.

Why does intimate wear need a material rethink?

The global intimate-apparel category encompasses everything from everyday underwear and sleepwear to shapewear, nursing garments and sports bras. One industry estimate valued the market at approximately $97.3 billion in 2025 and projects it to reach $169.4 billion by 2035. As the category grows, expectations around comfort, functionality, inclusivity, premium materials and more responsible production are growing with it.

Yet the material composition of these garments remains challenging.

Even a relatively small percentage of elastane can complicate textile recycling. Structured products such as bras may contain numerous materials and separately manufactured components, including clasps, underwires, elastic bands, foams and support structures. These combinations are difficult to disassemble and often lack a practical circular pathway.

This reflects a wider industry challenge. The European Environment Agency reports that much of Europe’s textile waste still enters mixed waste streams, while sorting and recycling capacity needs to expand significantly. Textile Exchange has also called for the industry to reduce its reliance on virgin fossil-based synthetics and increase the use of recycled and renewable alternatives. For products worn close to the body, there is another important consideration: material safety. Performance cannot be separated from prolonged skin contact, comfort and chemical safety. The question is therefore not only how a material performs during use, but also what it is made from and what can happen to it after disposal.

Placing function exactly where it is needed

Shlomit Ariel’s thesis research, supervised by Yoav Sterman, examines how auxetic structures printed using flexible biopolymer materials can be bonded directly to natural-fibre knitted textiles.

Auxetic structures are geometries designed to respond to tension in distinctive ways, enabling their behaviour to be adjusted through changes to the pattern, density and direction of the design. Using digital and parametric design methods, Shlomit developed printed structures that introduce targeted flexibility, elastic recovery, support and structure into specific areas of a textile.

Rather than adding a conventional elastic band or assembling a separate plastic component, this approach allows functionality to be placed directly onto the textile only where it is required. The geometry, density and positioning of each structure can be adapted according to the needs of the garment and body.

For this exploration, Shlomit selected BioCir® Flex, Balena’s flexible biopolymer material developed for additive manufacturing, as the material used to print her auxetic structures. Its flexibility and compatibility with 3D printing enabled her to translate the digitally developed patterns into durable, functional structures bonded directly to the textile.

The approach brings together:

• Natural-fibre knitted textiles

• Auxetic structures developed by Shlomit Ariel and printed using BioCir® Flex

• Digital and parametric design

• Targeted areas of stretch, recovery and support

• Fewer separately manufactured functional components

• Reduced reliance on conventional fossil-based elastics in specific applications

• More considered end-of-life possibilities

Gaia:
A nursing-wear concept

Shlomit applied this research to Gaia, a conceptual nursing bra and underwear set made using cotton-knit fabric and heat-bonded auxetic structures printed with BioCir® Flex.

Nursing wear presents a particularly valuable test case. These garments must adapt to changes in the body, provide reliable support, remain soft against sensitive skin, allow practical access and adjustment, and withstand repeated wear and washing. Traditionally, achieving this combination of qualities requires multiple synthetic materials and separately manufactured components.

Through Gaia, Shlomit explored how areas of support, stretch and adjustability as well as functional elements such as clasps could be created through strategically placed auxetic structures.

The concept demonstrates the potential to integrate specific functions directly into a textile while reducing reliance on conventional, persistent plastic components.

The project was developed as part of Shlomit’s thesis research and remains a research concept rather than a commercial product or a Balena-commissioned design. It provides a physical example of how next-generation materials could support a different design process: one in which performance, material composition, skin contact and end-of-life considerations are examined together from the outset

Material performance with material health in mind

BioCir® is Balena’s family of advanced biopolymer materials, developed to deliver the flexibility, durability and mechanical performance required for long-lasting consumer products. Its formulations are compatible with established manufacturing technologies, including extrusion, injection moulding and 3D printing, helping designers and manufacturers explore new material possibilities using familiar processes.

Balena believes that materials should be assessed not only by performance, cost or environmental footprint, but also by their effects on people. BioCir® materials have been developed with material health in mind and meet standards including REACH, RoHS and EN 71. ISO 10993-5 testing also showed no cytotoxic effects on human cells.

These material-level credentials are especially relevant when exploring close-to-body applications, although every finished product would require its own development, validation and testing before commercial use.

Beyond nursing wear

Although Gaia focuses on nursing underwear, Shlomit’s design and manufacturing approach could have wider relevance across intimate apparel, sportswear and other close-to-body products, including:

Bras and bralettes / Underwear and shapewear / Maternity and nursing garments / Adaptive intimate wear / Sports bras / Performance base layers / Close-to-skin activewear / Other garments requiring targeted stretch, recovery and support

Because Shlomit’s auxetic patterns and material placement can be digitally adjusted, the research may also point to future opportunities for customised support, more precise performance and localised manufacturing. Structures could be adapted for different bodies, garment zones or functional requirements without changing the entire textile construction.

Shlomit Ariel’s Gaia project demonstrates how BioCir® Flex can be used within a new approach to textile and garment design. By combining natural-fibre textiles with precisely placed auxetic structures developed through her thesis research and printed using BioCir® Flex, the project explores how targeted functionality might be introduced while reducing reliance on certain conventional synthetic components.

For Balena, the work provides an inspiring example of how independent designers and researchers can use BioCir® materials to investigate new applications and challenge established approaches to product construction.