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Castomize’s co-founder and CEO Abel Teo on revolutionising orthopaedic casts

Updated: Apr 23

Castomize’s co-founder and CEO, Abel Teo
Castomize’s co-founder and CEO, Abel Teo

The plaster/fibreglass orthopaedic cast has existed in various forms for over 200 years. While its efficacy informs its longevity, the solution has drawbacks like being uncomfortable to wear and tedious to apply/remove. Singapore-based startup Castomize has introduced a 4D-printed cast that improves on the traditional option across every metric, for what may eventually be the new industry standard in orthopaedic casting.


Castomize’s secret sauce is 4D printing. The cast is first 3D-printed in the startup’s proprietary polymer, which is hard and rigid at room temperature. When heated to around 55°C, however, it softens to become more malleable. This change in physical properties is 4D printing’s fourth, final dimension: time. Applying Castomize’s cast is thus a simple process of heating it, then shaping it around the limb to be immobilised before letting it cool down and harden again.

4D-printed cast for fractures by Castomize
Castomize’s 4D-printed cast

Castomize’s cast matches plaster/fibreglass ones in terms of efficacy, while improving on them by also being light, open, waterproof, infinitely re-adjustable, and easy to apply/remove. These features translate to better care from clinicians, as well as an improved healing journey for the patient. Indeed, various organisations have already noted the potential for Castomize’s solution to significantly improve fracture care, and the startup is already securing sales contracts regionally as it transitions to revenue generation.


“3D and 4D printing are slow, which makes it difficult to scale production up when we close larger deals,” notes Castomize’s co-founder and CEO Abel Teo. “This was why we developed our cast to also be suitable for injection moulding, which is much faster and more efficient.” He shares more details about Castomize and its product below.

How did Castomize come about?

This actually started as a student project that was completed and set aside 5 years ago. We pivoted towards orthopaedic casts after our co-founder Mao fractured his arm while mountaineering, and complained so much about his cast and how inconvenient it was. (laughs)


It was clear to us then that there is room for improvement in this space, and the founding team believed that it had the necessary expertise to develop something better. When we received a grant from [Singapore’s] National Research Foundation, we decided to incorporate Castomize – that grant was the threshold we crossed to go from having an idea to being a startup.


What were some technical challenges that the team had to overcome to arrive at Castomize’s current stage of product development?


Developing the right materials was very tough for us, because it’s difficult to precisely mix the necessary solids and liquid additives in small batches. This isn’t an issue for larger companies because they can just scale things up and produce a larger quantity of whatever’s needed, but we lack the scale to do so. Our CTO Johannes overcame this by developing a machine that can precisely mix small batches of the necessary materials, which let us perform both R&D and production on a much, much smaller scale. We’re exploring the possibility of patenting this method of creating materials on a small scale for R&D work.

Close up of 4D-printed cast for fractures by Castomize
Proprietary material aside, the cast’s lattice structure is a network of springs that gives it self-moulding properties when it is soft and malleable

Castomize has approached things from an engineering perspective to improve on the industry standard fibreglass and plaster cast. Was it difficult to get doctors interested since you are not doctors yourselves?


[Co-founder and COO] Eleora has a background in biomedical engineering, co-ownership of a few medical device patents, and experience working with doctors and hospitals, so doctors are actually fairly open to working with us.


The tough part was trying to get our foot in the door initially. Things only started to turn around when we exhibited at [Singapore Week of Innovation and Technology] 2022. That was when we connected with National Healthcare Group, which led to the co-development project for our cast. This gave us crucial access to orthopaedic surgeons and nurses, who provided the necessary feedback to iterate on our product. I think we’re on the right track so far, since their comments are getting more positive each time we meet them. (laughs)

Johannes Sunarko CTO Castomize with NHG clinicians
CTO Johannes Sunarko (left) consulting with clinicians under Singapore’s NHG

Does this mean you’ll soon complete product development?

We expect to finalise the first-generation version of our cast within the next 4 to 5 months. We are still making minor tweaks in areas including the cast’s size and outer material as well. These are all minor design tweaks though. The only remaining major consideration is the fasteners’ design, which needs to be ideal for both doctors and patients.

Are there technical limits for Castomize’s first generation of casts?

Our current casts cannot be used by very small children and people with really large arms. For these two groups of patients, we will need to manufacture custom casts.


What’s next for your casts?

We are exploring modular designs that can immobilise different parts of the body selectively. This is the next step in our product roadmap, and we’re aiming for it to be ready in a year or two. Beyond just using 4D-printing for orthopaedic casts, we see potential applications elsewhere as well. Within the medical space, drug delivery systems and blood vessel stents are of interest to us. Outside of it, anything is possible – entertainment packaging, for example, was something we were previously exploring with an external partner.


And where do you want to bring the company?

We’ve patented the application of 4D-printing to orthopaedic casts, and we want to quickly dominate this space before selling the entire product line to a bigger player in the industry, for an exit that will also be favourable to our investors. Castomize will, however, continue to explore and develop other applications for 4D-printing, like those I’ve previously mentioned.

Castomize VentureBlick 4D-printed cast


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