Imperial College London: 3D Printing Improved Biocompatible Implant Packaging

Share this Article

Cristina Gentili recently presented a thesis, ‘3D Printed Instrumented Packaging for Implantable Devices,’ to the Centre of Bio-Inspired Technology at the Imperial College London. While there is much research focused on the creation of 3D printed medical models, surgical planning devices, and implants, this study centers on the importance of effective, biocompatible packaging for medical electronic implants. Such devices offer critical monitoring for patients who may be suffering from one or more serious conditions like heart disease, diabetes, and other chronic health issues.

Pointing out that the human body ‘is a critical site,’ Gentili states that device packaging is of the utmost importance due to risk of rejection of damage to tissue. Packaging must offer the following:

  • Biocompatibility
  • Biostability
  • Strength
  • Smooth, soft texture

Materials such as titanium, ceramic, or glass are often used for device packaging as they are able to offer proper resistance against moisture and can also hold up against stress and wear.

Production processes today may be extremely expensive however, as well as complicated and challenging, leaving Gentili to suggest more affordable—and fast—production of polymeric packages via digital light processing (DLP). There are still obstacles to overcome in such manufacturing, though, such as adhesion issues, high porosity, and inferior surface quality.

“Active implantable medical devices are complex systems under extremely tight design constraints. Requirements for implants involve general common design rules and principles, but application specific requirements, as well,” states Gentili. “For instance, the device specific function, sensing mechanism, placement in the body, implantation time… and so on, have all to be taken into account in the whole design phase.”

Active implant scheme

Active implantable medical devices are divided into two categories: diagnostic and therapeutic. Typically used for monitoring, diagnostic AIMDs detect sugar levels, blood pressure, inner ocular pressure, and other physiological signals. Therapeutic AIMDs often act as pacemakers, neurostimulators, recorders, modulators, and more. Main features required are:

  • Ability to receive/sense electric signals
  • Ability to analyze input
  • Actuation, depending on signals arriving from human tissue, resulting in action and electrical output

Active implant basic features and requirements

One of the most difficult challenges in creating packaging for such devices is the hermeticity requirement. More traditional methods for measurement would include exposure in a pressurized helium chamber; however, that technique is not suitable for polymers as they are permeable to helium.

An in situ monitoring system was used to measure humidity and temperature, with data shared through Bluetooth. These techniques offer ‘the best sensitivity’ regarding leak detection and permeation of the implant package. The downside in using these systems, however, is that an electronic structure must accompany such sensors. For this study, the system was designed in a 29×29 mm printed circuit board.

Sensor measurements sent by Bluetooth to the iPhone App. (a) Characteristic values read and notification. (b) Log view.

“… the advantages are that any package material can be used and there are no sensibility limitations due to cavity dimensions,” states Gentili. “In fact, in situ methods are independent on the volume. Furthermore, it is possible to detect the outgassing of internal materials, as well.”

Humidity monitoring system block diagram

“For what concerns the estimated lifetime inside the human body organism, to allow a temperature variation of maximum 4◦C, it turns that the maximum relative humidity allowed in the cavity, to not make condensation happen, is about 80%,” concluded Gentili. “This upperlimit was reached after 4065 minutes of test at 77◦C, which are equivalent to about 37 days (considering sensors tolerances) at human body temperature.

“As a last remark, it has been highlighted that corrosion problems due to ionic contamination in printed circuit board assemblies may further lower the maximum relative humidity level. Therefore, considering this last safer limit, the implant lifetime is estimated to be about 20 days. Hence, the final conclusions assert that the developed package structure is not suitable for a long term implantation. To make it acceptable for at least three months inside the human body organism, it actually needs improvements concerning both the substrate permeability and the sealing process.”

Composite drawings – Top and Bottom layers of Humidity Monitoring System

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘3D Printed Instrumented Packaging for Implantable Devices’]

 

Share this Article


Recent News

MULTI-FUN Consortium Aims to Improve Metal 3D Printing

JCRMRG’s 3D Health Hackathon Aims for Sustainable 3D Printed PPE



Categories

3D Design

3D Printed Art

3D printed automobiles

3D Printed Food


You May Also Like

3D Printing Webinar and Virtual Event Roundup, July 7, 2020

We’ve got plenty of 3D printing webinars and virtual events to tell you about for this coming week, starting with nScrypt’s webinar today. 3Ding and Formlabs will each hold a...

Featured

Interview: Redefine Meat CEO’s Insight into New Alternative Meat & 3D-Printed Food

Amid lifestyle changes toward wellness and health, as well as an inclination of industries to adopt disruptive technologies, the 3D printed plant-based meat industry could go from niche to mainstream...

NIST Grants $1.4 Million to America Makes for 3D Printed PPE

As the COVID-19 pandemic has swept the world and changed life as we know it in many ways—along with opening up many questions for the future—makers, researchers, and medical inventors...

Featured

French Army Deploys Massive Military Print Farm for Spare Parts

The French Army has recently partnered with HAVA3D, a prominent distributor and integrator of additive manufacturing solutions based out of Le Mans, France, to deploy one of the largest 3D...


Shop

View our broad assortment of in house and third party products.