New Squishy 3D Printing Method Could Make Brain Surgery Safer

A new 3D printing technique using silicone can create accurate models of your brain’s blood vessels, allowing neurosurgeons to practice with more realistic simulations before operating, according to our recently published research.

Many neurosurgeons practice each operation before entering the operating room based on models what they know about the patient’s brain. But the current models that neurosurgeons use for training not mimicking real blood vessels well. They provide unrealistic tactile feedback, lack small but important structural details, and often exclude entire anatomical components that determine how each procedure will be performed. Realistic and personalized replicas of patients’ brains in preoperative simulations could reduce errors in actual surgical procedures.

3D printinghowever, could make replicas with the soft feel and structural precision that surgeons need.

The Squish Factor

3D printing is generally thought of as a process of depositing layer upon layer of molten plastic that solidifies when building a freestanding structure. Unfortunately, many flexible materials do not melt and resolidify like the plastic filaments used by 3D printers typically do. Users only get one shot with soft materials like silicone – they have to be printed in a liquid state and then irreversibly solidified.

How do you create a complex 3D shape from a liquid without ending up with a collapsing puddle or blob?

The researchers developed a broad approach called on-board 3D printing for this purpose. With this technique, the “ink” is deposited inside a bath of a second support material intended to circulate around the printing nozzle and to trap the ink in the place just after the removal of the nozzle. This allows users to create complex shapes from liquids by keeping them trapped in three-dimensional space until the printed structure solidifies. Embedded 3D printing has been effective in structuring a variety of soft materials such as hydrogels, microparticles and even living cells.

However, printing with silicone remained difficult. Liquid silicone is an oil, while most carrier materials are water-based. Oil and water have a high interfacial tension, which is the driving force behind why oil droplets take on circular shapes in water. This force also causes 3D printed silicone structures to deform, even in a support.

Worse still, these interfacial forces cause small diameter silicone elements to break into droplets as they are printed. A lot of research has gone into making silicone materials that can be printed without supportbut these heavy modifications also change the properties that users care about, such as the softness and elasticity of the silicone.

3D printing silicone with AMULIT

As researchers working at the interface of soft matter physics, mechanical engineeringAnd materials sciencewe decided to tackle the problem of interfacial tension by developing a silicone oil carrier material.

We felt that most silicone-based inks would be chemically similar to our silicone support material, greatly reducing interfacial tension, but also different enough to stay separate when put together for 3D printing. We created many candidate support materials, but found that the best approach was to create a dense emulsion of silicone oil and water. You can think of it as a crystalline mayonnaise, made of micro-droplets of water encased in a continuum of silicone oil. We call this method additive manufacturing with ultra-low interfacial tension or AMULIT.

With our AMULIT support, we were able to print standard silicone at high resolution, creating features as small as 8 micrometers (about 0.0003 inch) in diameter. Printed structures are as stretchy and durable as their traditionally molded counterparts.

These capabilities have allowed us to 3D print accurate models of a patient’s brain blood vessels based on a 3D scan as well as a functional heart valve model based on average human anatomy.

3D printing of silicone in the field of health

Silicone is a essential component of countless productsfrom everyday consumer goods like kitchen utensils and toys to advanced technologies in the electronics, aerospace and healthcare sectors.

Silicone products are usually made by pouring or injecting liquid silicone into a mold and removing the molding after solidification. The cost and difficulty of making high-precision molds limits manufacturers to products with only a few predetermined sizes, shapes, and designs. Removing delicate silicone structures from molds without damaging them is an additional barrier, and manufacturing defects increase when casting very complex structures.

Overcoming these challenges could enable the development of advanced silicone-based technologies in the healthcare industry, where personalized implants or imitations of patient-specific physiological structures could transform care.

This article was originally published on X by Senthilkumar Duraivel and Thomas Angelini at the University of Florida. Read it original article here.