Additive Manufacturing for Medical Devices

What are the main challenges and opportunities in developing silicone applications for use in healthcare?

Healthcare professionals, institutions and systems are facing greater challenges than ever in delivering efficient and cost-effective solutions in a great variety of areas, from the need to provide care to ageing populations, dealing with unprecedented events such as global pandemics and responding to severe humanitarian and public health crises. These challenges need to be met at the same time as having to respond to patients’ ongoing demands for better and more comfortable care in all circumstances, which are compatible with economic pressures in both the public and private health sectors.

New technologies, in particular digital solutions, are facilitating progress not only in developing new products, but also in enabling collaboration between researchers, caregivers, healthcare managers, designers, engineers, manufacturers, patients, etc.

In this blog, we focus on how new materials, in particular silicones, and new techniques such as digitization and Additive Manufacturing, are key elements in improving the quality of healthcare for patients while improving performance, both technically and economically, for healthcare providers.

What are the main benefits of medical grade silicones in healthcare applications?

Before we look at current progress in new digital and Additive Manufacturing processes, it’s important to remind readers that medical-grade silicones have been used in healthcare and pharmaceutical applications for over two-thirds of a century. Their use varies from non-invasive wound care adhesives to orthoses and prostheses, via implants, drug-delivery systems, surgical tools and devices, diagnostic and monitoring systems, long-term implants, etc.  

Whatever the application, in the operating theater, on the skin or inside the body, silicones are materials of choice because of their biocompatibility, chemical inertness, hypo-allergenicity, versatile and high-performance physical properties and stability across a wide range of conditions. 

Silicone elastomers dedicated to additive manufacturing

From prototyping to functional parts

Here is a short (non-exhaustive) list of some well-established uses of silicones in healthcare and in the next section, we will outline how these applications are being bolstered by digital technology and Additive Manufacturing:

Medical grade Silicones for General and Advanced Surgery:

Prosthetics and Orthotics:

Manufacturers of prosthetics devices, such as artificial limbs, use silicones for their mechanical properties and for the comfort they provide to end users. Prosthetic devices made with silicones are lightweight and feature outstanding feel and appearance features. 

Medical Valves and other fluid management devices:

Devices used for fluid management in medical devices include tubing, catheters, valves, etc.

Cardiac Resynchronization Devices:

These long-term Implants, generally referred to as pacemakers, adjust to abnormally high or irregular heart rhythms or other potentially life-threatening cardiac anomalies.

Pharmaceutical drug delivery systems:

Used for the transfer of critical pharmaceutical fluids, excipients and drugs, offering unrivaled biocompatibility, chemical inertness, thermal stability, flexible physical properties and environmental stability.

Pharmaceutical Manufacturing

Silicones are used for processing critical fluids in pharmaceutical manufacturing: peristaltic pump tubing, transfer tubing, high pressure reinforced hoses, gaskets and seals. Flexibility and easy sterilization (steam, heat, radiation) are ideal for carriers of critical fluids.

Diagnostics and monitoring

Medical-grade silicones are used in disposable and home-health devices, microfluidic chips, gaskets and cushioning pads for their inertness, ease of processing and superior biocompatibility These devices have become a lifestyle trend to monitor health parameters on a daily basis, including innovative wearable solutions such as watches, implantable sensors, smart textiles, and for on-demand access to health data like oxygen, stress, blood glucose, or fitness levels.  

In Vitro Diagnostics (IVD)

In Vitro Diagnostics (IVD) point of care tests (POCT) are emerging trends in diagnosis, especially for disposable and home-health options, eliminating the need to travel to medical facilities. Silicones facilitate fabrication on a micrometer scale and integration of valves, micropumps and other components.

Transdermal Drug Delivery

A Transdermal Drug Delivery System (TDDS) is an adhesive patch that contains a drug or medication which is placed on the skin to deliver specific doses over time into the body, at a defined release rate. Silicone adhesives provide many advantages compared to other traditional adhesive technologies, including reduced skin irritation and good compatibility with the main drugs used in this field.

Drug Eluting Devices

The key advantages is to target accurate drug delivery to specific locations, eliminating reliance on patient compliance. Silicone is the highest standard for biomaterials because of its permeable matrix structures, creating space for APIs to reside and pass through over time in drug eluting devices.

Stents

These devices keep coronary pathways open and often require additional biocompatible silicone coatings to provide corrosion resistance and decrease tissue ingrowth. 

Neurostimulation Devices

These surgically-implanted devices function through thin wires or leads. Medical grade silicones are used for gaskets, seals, adhesives, lead insulators, and drug delivery systems, etc.

Dentistry

Silicones are used to make replicas of hard and soft oral tissue models, diagnoses or fabrication of prosthetic devices, ensuring high fidelity, reliable impression and reproduction.

This long history in the use of medical-grade silicones and wide range of applications are living proof that healthcare professionals have come to trust silicone experts because they are able to develop tailor-made grades matching performance requirements, such as selected hardness, adjusted kinetics, viscosity, color, etc. This understanding of the technical challenges and long-term relationships are the keys for developing new innovations in materials, digital end-to-end processes and Additive Manufacturing solutions.

Silicone School

Everything you need to know about silicone technologies.

Why is the combination of digital technologies, Additive Manufacturing and silicones particularly well-suited for healthcare applications?

In this section, we look at some of the main applications that currently combine digital technologies, Additive Manufacturing and silicones. We also look at the overall market, its development and take a quick glimpse of promising new medical applications for the future.

To begin with, Star Rapid, a market research leader, reports that the use of medical Additive Manufacturing applications have more than quadrupled in the last five years, rising from $6 billion in 2017 to an estimated $26 billion in 2022.

They explain that “the advantage of Additive Manufacturing comes from creating complex structures that vary in complexity, customization, light weight, strength and speed. As Additive Manufacturing for medical devices continues to gain momentum, there are five main areas where we are seeing the most growth opportunity from this evolving technology.” 

Following on their lead, we propose a quick summary of these five areas:

Dentistry 

This is currently the largest medical market using Additive Manufacturing applications, for a wide range of dentistry and related orthodontics, including dentures, bridges, crowns, braces and implants. Digital dentistry has truly established an end-to-end workflow which typically begins with a scannable model converted into 3D digital data that is directly used to make 3D printed dental appliances using a range of substrates from flexible polymers to rigid titanium. Many dental cabinets now have 3D scanning devices on wheels that can be used by several dentists, with the data being transferred to specialized printers (in-house or outsourced), which are configured to produce immediate solutions.

Anatomical Models

In the past, medical practitioners and students worked on human corpses for their research, training and to chart a surgical intervention. Today, when physicians and clinicians consider individual treatments, they now have access to very accurate models, based on the specific physiological characteristics of their patients, including organs or other bodily parts, as well as the specific pathology they need to deal with, such as tumors. As in dentistry, advanced medical imaging can be used to fabricate real 3D models, replicating shape and degrees of hardness and flexibility. Beyond the surface, scanners dig deeper, including into tendons, ligaments and even vascular structures. These techniques are used in hundreds of hospitals worldwide, both for surgical preparation and to train students and paramedics for more efficient first responder intervention.

Medical tools, valves and fluid management devices

This wide range of medical devices, used in surgery as well as in home or hospital care, includes catheters, personalized grips, variable throughput pumps for pharmaceutical treatments or respiratory machines, etc. Additive Manufacturing is particularly interesting for making specific devices that are adapted to the patient’s needs and anatomy, but also for making small batches of devices for rare diseases. As is the case in dentistry, Additive Manufacturingapplications are also used to make equipment on the spot in places that are far from medical hubs and, for example, in developing countries, where critical devices can be made with small 3D printers using files that are exchanged between health workers and faraway design units. The combination of digital design systems, 3d printing and the intrinsic characteristics pf silicones – biocompatibility, chemical inertness, thermal stability, flexible physical properties and environmental stability – make this a particularly promising field.  

Prosthetics and orthotics

This area has used silicones and combinations of multiple materials for making highly personalized anatomical devices that are functional, robust and, above all, contribute to the patient’s comfort and mobility. Additive manufacturing technology is a huge booster for making more accurate body parts, for use internally (such as hip joints) or externally (such as missing limbs). The advantages of Additive Manufacturing are to streamline preparation upstream through digital scanning, facilitating measurements, fitting and adjustments. It also reduces costs since there is less need for highly-skilled specialists to make the parts and, as is the case for medical tools or dentistry, Additive Manufacturing makes it possible to make prosthetics and orthotics in parts of the world that are far from medical hubs. This is particularly relevant for developing countries or war-torn territories.

Health monitoring, drug delivery and implants

This area is really at the forefront to solve complex applications to monitor people’s health outside medical facilities (both night and day) or to make customized micro-devices that can be inserted into specific parts of the body to monitor behavior er deliver drugs to specific areas for long periods of time. For example, MIT and Harvard researchers have developed an ingestible device that can deliver life-saving medicines and remain in the patient’s stomach for a month. This new generation of in-body devices will benefit greatly from the combination of digital technology, Additive Manufacturing and the intrinsic qualities of medical-grade silicones, enabling treatment as well as the capacity to collect data in real time and respond to emergency situations.