Customer’s Application
The client is an innovative medical technology startup focused on developing a next-generation continuous glucose monitoring (CGM) sensor. This device is designed for long-term implantation in diabetic patients to provide real-time blood glucose data. The critical application is the complete potting of the sensor’s microelectronics and the hermetic sealing of the device’s biocompatible housing. The entire potted assembly is intended for direct, long-term contact with subcutaneous human tissue.
The Engineering Challenge
Developing a safe and reliable implantable medical device adhesive presents a formidable set of material science challenges, where failure can have direct consequences for patient health.
- Biocompatibility: The absolute primary challenge is ensuring that the cured epoxy is non-toxic, non-cytotoxic, and does not leach any harmful chemicals or compounds into the patient’s body over time. Any adverse biological response, from minor skin irritation to systemic toxicity, is unacceptable. Failure to demonstrate biocompatibility to regulatory bodies like the FDA is an insurmountable barrier to market entry.
- Sterilisation Resistance: Every implantable device must be sterilised before it can be used in a surgical procedure. The epoxy encapsulant must be able to withstand multiple cycles of common medical sterilisation methods – such as steam autoclaving (high heat, steam, and pressure), ethylene oxide (EtO) gas, or gamma radiation. The epoxy potting compound must withstand these harsh sterilisation cycles without any degradation of its physical properties, loss of adhesion, or cracking.
- Barrier Properties: The potted sensor must be completely impervious to bodily fluids. These fluids are saline and contain various biological agents that are corrosive to electronic components. The epoxy bonding adhesive must form a perfect, long-lasting hermetic seal to prevent any moisture ingress that would lead to a short circuit and device failure.
- Adhesion and Durability: The epoxy must adhere tenaciously to the various substrates used in the device, such as its titanium housing, the ceramic sensor element, and any PEEK (polyether ether ketone) polymer components. It must also possess a degree of toughness and flexibility to accommodate minor movements and stresses within the body without delaminating or failing mechanically.
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The Kohesi Bond Solution | Custom Engineered Certainty
The selection of the potting compound was a critical-path decision in the device’s development, requiring a material with a specific portfolio of certifications and performance characteristics.
- USP Class VI Certification: This is the most crucial requirement for any material intended for implantation. The USP Class VI epoxy has been proven biocompatible through the United States Pharmacopoeia’s stringent (USP) Class VI testing. These in vivo tests involve implanting the material and its extracts into test subjects and observing for any signs of local, systemic, or intracutaneous toxicity.
- ISO 10993-5 Cytotoxicity: In addition to USP Class VI, certification to the ISO 10993-5 standard is highly desirable. This in vitro test provides further evidence of safety by demonstrating that the material is not toxic to living cells in a laboratory setting.
- Sterilisation Resistance: The formulation must be explicitly tested and proven to withstand repeated sterilisation cycles. For example, it must show no loss of adhesion or mechanical strength after being subjected to over 100 steam autoclave cycles at 134°C and 20 psi.
- Low Water Absorption: To ensure long-term protection of the sensitive electronics, the cured epoxy must exhibit minimal water absorption over time when fully immersed.
- High Bond Strength: The material must provide excellent, durable adhesion to medical-grade substrates, including metals like titanium and stainless steel and high-performance polymers like PEEK and polysulfone.
To meet the application’s unique requirements, Kohesi Bond’s adhesive experts custom-formulated KB 1452 HT-2. This highly specialised, two-part biocompatible epoxy adhesive is engineered to exceed USP Class VI and ISO 10993-5 standards for biocompatibility and cytotoxicity. Furthermore, KB 1452 HT-2 demonstrates superior resistance to repeated autoclaving and various sterilisation cycles. It provides robust healthcare equipment bonding to a wide range of plastics, metals, and ceramics while maintaining stability under extreme temperatures.
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KB 1452 HT-2
Kohesi Bond KB 1452 HT-2 is a two component, room temperature curing, medical grade epoxy system suitable for bonding, sealing, potting and encapsulation. Read More
The Result
The CGM device, potted with KB 1452 HT-2, successfully achieved USP Class VI certified adhesive and ISO 10993-5 certifications, clearing the path for human clinical trials and FDA submission. In accelerated testing simulating five years of continuous implantation, the sensors demonstrated zero failures, proving the epoxy’s exceptional reliability in physiological environments.
By choosing medical-grade epoxy adhesives that are pre-certified, the manufacturer effectively de-risked the development process and bypassed the time-consuming gamble of testing unproven materials.
As one of the leading medical-grade adhesive manufacturers, Kohesi Bond delivered more than just an epoxy for medical devices. It provided the regulatory certainty and accelerated speed-to-market essential for critical medical device bonding epoxy innovation.
Technical Specifications Summary
Parameter | Requirement | Significance |
Biocompatibility | USP Class VI Certified | A pass/fail, non-negotiable requirement for implantable medical devices. |
Cytotoxicity | ISO 10993-5 Certified | Provides in vitro proof that the material is non-toxic to living cells. |
Sterilisation Resistance | Withstands >100 Autoclave Cycles | Ensures material integrity and performance for reusable or pre-sterilised devices. |
Service Temperature Range | -60°F to +450°F | Guarantees stability during steam autoclaving and at normal body temperature. |
Adhesion Substrates | Titanium, PEEK, Ceramics, Stainless Steel | Demonstrates strong bonding to common materials used in medical device construction. |
Water Absorption (24hr) | < 0.1% | Prevents moisture ingress from bodily fluids, protecting sensitive electronics long-term. |
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Utsav Shah is a 34-year-old entrepreneur with a passion for scientific discovery. Utsav’s journey began with a deep dive into materials science, earning degrees from USC and the Institute of Chemical Technology. He’s the visionary founder of Kohesi Bond, a top-rated adhesive manufacturer, and Cenerge Engineering Solutions, a leader in heat exchangers and cryogenic pumps. With over a decade of experience, Utsav consults across various industries, ensuring they have the perfect adhesive solution for their needs. Connect with him on LinkedIn!
