Flexible medical electronic coating technology: Precision coating of gold, silver, and platinum empowers wearable medical and neural regulation

1、 Introduction: Opportunities in the Era of Flexible Medical Electronics

Flexible medical electronics is one of the most transformative technological directions in the field of healthcare in recent years. By combining electronic devices with flexible and stretchable substrates, flexible medical electronics can achieve conformal bonding with human skin, tissue, and even organs, providing a new solution for scenarios such as remote patient monitoring, chronic disease management, neural regulation, and implantable healthcare.

According to industry research data, the global flexible hybrid electronics market is expected to reach approximately $136 million in 2024, with a compound annual growth rate of 14.8% from 2025 to 2032. The global wearable patch market is estimated to be worth approximately $9.95 billion in 2024 and is expected to reach $15.71 billion by 2030. In the sub field of medical flexible bioelectrodes, the global market size is expected to reach approximately 245 million US dollars by 2025, and is expected to maintain a steady growth trend until 2032.

The core device of flexible medical electronics - flexible electrodes, whose performance largely depends on the selection of conductive layer materials and coating processes. How to achieve high conductivity, low contact impedance, excellent biocompatibility, and long-term reliability of metal coatings on flexible polymer substrates is one of the most core technical propositions in this field.

2、 Core requirements for coating technology in flexible medical electronics

Unlike traditional rigid electronic devices, flexible medical electronics impose more stringent comprehensive requirements on electrode coating layers:

• Low contact impedance.The impedance at the electrode tissue/skin interface is a key parameter that determines signal quality. Low impedance means higher signal-to-noise ratio and more accurate signal acquisition.
• High conductivity and mechanical stability.The coating layer needs to have excellent conductivity and maintain stable electrical performance under mechanical deformation conditions such as repeated bending and stretching.
• Biocompatibility.As devices that come into direct contact with the skin, tissues, and even implantation sites, coating materials need to be non-toxic, non irritating, and meet the biosafety requirements for long-term wear or implantation. Materials in direct contact with neural tissue must comply with ISO 10993 and GB/T 16886 series biocompatibility standards.
• Flexibility and adhesion.The coating layer needs to be firmly combined with the flexible substrate, and should not fall off or crack in dynamic usage scenarios such as bending and twisting.

3、 Advanced Institute Technology: A professional manufacturer of flexible medical electronic coating

Advanced Institute (Shenzhen) Technology Co., Ltd. was established in 2016, headquartered in Bao'an District, Shenzhen. It is a national high-tech enterprise specializing in shielding materials, insulation materials, thermal conductivity materials, and precious metal coatings. The company has its own registered trademark "Research Platinum" and has dual production bases in Shenzhen and Dongguan. It has passed ISO9001 quality management system certification and its products comply with GJB 773A aerospace standards and RoHS environmental requirements.

In the field of coating technology, the company has independently built magnetron sputtering and vacuum evaporation production lines, using roll to roll continuous production technology, which can continuously deposit metal layers on the surface of flexible polymer films. Suitable substrates include various flexible materials such as FEP, PI, PET, LCP, PPS, PEN, PP, etc., and can be plated with metals including gold, silver, copper, aluminum, tin, nickel, titanium, platinum, etc. Relying on advanced physical vapor deposition (PVD) technology, the company has achieved nanometer level precise control of metal thin films on the substrate surface, with thickness ranging from a few nanometers to several hundred nanometers, ensuring extremely high uniformity and density.

Core process capability:

• Plasma pretreatment activation.In response to the problem of insufficient bonding strength between metal and polymer substrates, Advanced Institute Technology has developed a plasma pretreatment process, which effectively improves the bonding strength between the substrate and the metal layer by bombarding the substrate surface with plasma.
• Magnetron sputtering and vacuum evaporation.The company uses composite processes such as magnetron sputtering and vacuum evaporation to deposit metal coatings on flexible polymer film substrates such as PI (polyimide), PET, FEP, etc. The metal coating achieves stress transition from the substrate to the metal layer through gradient coating design, effectively avoiding interface delamination caused by modulus differences.
• Cyanide free gold plating and pulse electroplating.In the gold plating process, the company adopts cyanide free gold plating technology, which has significant advantages in reducing environmental pollution and improving operational safety. Simultaneously introducing pulse electroplating technology, by precisely controlling the switching time and frequency of the current, the porosity in the coating is effectively reduced, and the density and uniformity of the coating are improved.

4、 Flexible Medical Electronic Coating Solution

（1） Gold plated electrode - the preferred choice for low impedance and high biocompatibility

Gold has become one of the preferred materials for coating flexible medical electronic electrodes due to its excellent conductivity, chemical stability, and biocompatibility. The chemical inertness of gold endows gold-plated electrodes with excellent corrosion resistance, making them suitable for long-term skin contact and even implantation scenarios.

The electrode plated with gold (thickness about 2 μ m) on a flexible polyimide (PI) substrate has low impedance, which can achieve stable baseline and good signal acquisition effect. Gold plated flexible electrodes have been widely used in surface electromyography (sEMG), nerve stimulation electrodes, implantable medical device electrodes, and other scenarios.

• Low contact impedance, high signal-to-noise ratio
• Excellent biocompatibility, meeting long-term implantation requirements
• Flexible substrate adaptation (PI, PET, FEP, etc.)

（2） Platinum plated electrode - guarantee of high precision and long-term application

Platinum is one of the most widely used electrode materials in the field of neurophysiology. Platinum plated electrodes exhibit excellent performance in high-precision signal acquisition and long-term application scenarios due to their low resistivity characteristics. The sintered resistivity of the platinum electrode slurry developed by Advanced Institute Technology is as low as 1.65 μ Ω· cm, and the square resistance is as low as 20 ± 5m Ω/□, ensuring high sensitivity and fast response of the electrode.

In the field of precision treatment in neurosurgery, SEEG (Stereoscopic Electroencephalogram) electrode implantation technology achieves the localization of epileptic foci through minimally invasive methods. Platinum plated electrodes, with their low resistivity characteristics, are an ideal choice for high-frequency EEG monitoring and can effectively capture the transient discharge activity of epileptic foci. It also has important application value in deep brain stimulation (DBS) therapy.

• Extremely low resistivity, high sensitivity
• Suitable for high-frequency signal acquisition and neuroelectrophysiological monitoring
• Long term stability, suitable for implantable applications

（3） Silver plated electrode - a choice for balancing performance and cost

Silver is the metal material with the highest conductivity. Silver plated electrodes have both excellent conductivity and cost advantages, making them one of the most widely used coating solutions in flexible medical electronics.

• Excellent conductivity performance
• Significant cost advantage
• Flexible process, three-dimensional conductive network can be formed through nano silver wire composite technology

5、 Typical application scenarios

• Wearable medical monitoring devices.Flexible gold/silver plated electrodes are combined with flexible substrates such as PI and PET to adapt to wearable forms such as smart patches and wristbands, achieving long-term and comfortable physiological signal monitoring. The global wearable smart patch market is expected to reach approximately 3.165 billion US dollars by 2025 and is projected to reach 7.928 billion US dollars by 2032.
• Neural regulation and brain computer interface.Neurointerventional devices such as SEEG deep electrodes and deep brain stimulation (DBS) electrodes require extremely high biocompatibility and electrochemical performance of electrode materials. Platinum plated electrodes, with their low impedance and high-frequency response characteristics, have become an ideal choice for the acquisition and regulation of neurophysiological signals.
• Surface electromyography (sEMG).Flexible gold/silver/platinum plated electrodes are used for electromyographic signal acquisition in rehabilitation medicine, sports science, human-computer interaction and other scenarios.
• Implantable medical devices.Gold plated electrodes are suitable for long-term implantable scenarios due to their excellent biocompatibility and corrosion resistance. Materials in direct contact with neural tissue must comply with the ISO 10993 biocompatibility standard.
• Cardiovascular and endoscopic instruments.Advanced Institute Technology's silver/gold plated FEP and PI materials can be applied in medical scenarios such as cardiovascular catheters, endoscopes, and radiofrequency ablation electrodes.

6、 Conclusion

Flexible medical electronics are reshaping the future landscape of the healthcare industry. The performance of flexible electrodes, from wearable health monitoring to precise neural regulation, from surface electromyography to deep electroencephalography, largely depends on the choice of coating materials and processes.

Advanced Institute (Shenzhen) Technology Co., Ltd. relies on its independent process platform of roll to roll magnetron sputtering and vacuum evaporation to provide precision coating services such as gold plating, platinum plating, silver plating, etc. for the flexible medical electronics field. The company is committed to providing high-performance flexible electrode coating solutions for wearable medical, neural engineering, human-computer interaction and other fields, supported by core technologies such as plasma pretreatment, gradient coating design, and cyanide free gold plating, to help the continuous progress of China's high-end medical electronics industry.

*The data in this article is sourced from publicly available information on advanced technology and industry literature, and is provided for reference only. The product parameters are subject to the actual customized specifications*