Leak Prevention and Fluid Optimization in Wearable Medical Devices

Silicone is a popular material used in medical wearables due to its biocompatibility, flexibility, and durability. When it comes to fluid delivery, silicone tubing is often used due to its non-reactive nature with most biologics, making it ideal for medical applications. Silicone is also an excellent choice in sealing applications in a medical wearable device when a molded component will interface with other components in the fluid path. Silicone’s compression set properties allow it to maintain a leak-free seal even after sterilization and throughout the device's life cycle. Complex silicone molding is as much an art form as a science, so medical OEMs must work with a manufacturer specializing in this area.

Limiting leaks

Another design consideration for leak prevention is to ensure proper placement of tubing connections with adequate space for secure attachment. Stabilizing the tubing to prevent wear-induced leaks is critical. Using solvent-bondable materials like PVC eliminates the need for adhesives and simplifies assembly.

Component and material selection is of utmost importance in leak prevention for wearable medical devices.  

Select medical tubing based on fluid compatibility

Precision tubing is often used in wearable medical devices due to its tight tolerances, allowing for accurate fluid delivery or flow rate accuracy. When selecting precision pump and transfer tubing, it is important to consider the material properties of the tubing, the fluids being delivered, and other important functional requirements such as the targeted flow rate accuracy and pump life. The tubing should be selected based on its compatibility with the fluid, ensuring minimal risk of degradation or chemical reactions that can lead to leaks. The durometer hardness, modulus, elasticity, and other mechanical properties of the material are of critical consideration as the flexibility and kink resistance of the tube will depend upon this characteristic. 

When designing molded components, consider the entire assembled wearable device

Medical wearable devices often involve complex, micro-molded components requiring innovative manufacturing techniques for production. Complex molding allows for intricate shapes and designs needed for fluid delivery systems.

To prevent leaks, molded components must be designed with precision taking the entire assembled device design and components into consideration, ensuring that there is no room for error. Also, the molding should be designed to be durable and able to withstand wear over time without compromising the integrity of the fluid delivery system. 

In sealing applications, if a multi-material or two-shot component is desired rather than assembly, it is critical that molded thermoplastic components bond sufficiently with the mating material or component to avoid leak potential. Silicone is an excellent choice here, but the right grades of thermoplastic and silicone must be selected to ensure the chemical bond is sufficient. Two-shot molding (also known as 2k or double injection molding) is an advanced molding technique that involves molding both materials as part of one process and is an ideal choice for wearable devices because this reduces the number of components and assembly requirements.

Choose a supplier with experience in wearables assembly

Selecting the right component design and materials in concert with considering assembly requirements is a crucial step during the supplier selection and design process. Choosing a supplier experienced in the assembly of wearables during the design phase can ensure that the design, components, and materials selected are optimal and can be automated as much as possible to reduce cost. 

Designing and developing wearable medical devices requires careful consideration concerning fluid delivery, leak prevention, and optimizing the overall device’s functional requirements. Material selection, precision tubing, complex molding, and assembly are all critical components in the design process. Selecting an experienced and full-service supplier spanning all these categories during the supplier selection and design phase will prevent unforeseen challenges from arising during the development and commercialization phase. 

Saint-Gobain is a world-class manufacturer and full-service supplier of medical device components with vast experience with the commercialization of high-volume wearables. Contact us to get started.