Antimicrobial Coatings Reduce Implant Endotoxin Contamination

Advanced atomic layer deposition (ALD) thin film coating technology reduces microbial growth by hermetically encapsulating implanted devices.

The Picosun (Espoo, Finland) AGILE ultra-thin ALD coatings are designed to ensure pinhole-free coverage over even the smallest parts of an implanted device. The ALD coating impedes microbial adherence to implants, resulting in low values of bacterial endotoxin deposit. The thin film ALD coating is intrinsically biocompatible and remains inert inside the human body, uniformly covering even complex three dimensional (3D) structures with nanoscale details, such as micro-scale neural stimulators, diagnostic sensors, and more. The coating can also be applied to larger items, such as hip, knee, and dental implants.

In addition, the ALD coating completely blocks the diffusion of Na+, K+, Cl– and PO43- ions, which are known to be amongst the most corrosive ionic species in aqueous media, extending the lifetime and operational reliability of the implants, and reducing the need for corrective or replacement surgeries, thus improving the patient's quality of life. ALD oxide coating for medical implants include TiO₂, Al₂O₃, HfO₂, SiO₂, ZrO₂, Nb₂O₅, Ta₂O₅, AlN and TiN ALD films.

“ALD’s excellent barrier properties either as such, or combined with other encapsulation methods, support the trend of miniaturization and increased functionalization of medical microelectronics and enable a variety of novel products,” said Jani Kivioja, PhD, CTO of Picosun Group. “Introduction of ALD encapsulation can also help the manufacturers to replace expensive, noble metal components with cheaper materials, when ALD protection ensures the inertness of the devices inside the body.”

ALD is a thin-film deposition technique based on sequential use of gas phase chemical vapor deposition. The majority of ALD reactions use two chemicals precursors that react with the surface of a material one at a time in a sequential, self-limiting, manner. Through the repeated exposure to separate precursors, a thin film is slowly deposited. ALD is a key process in the fabrication of semiconductor devices, and part of the set of tools available for the synthesis of nanomaterials. ALD coatings can be applied at relatively low temperatures, which advocates their use also on sensitive materials such as plastics and polymers.

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