Towards biodegradable wireless implants

Abstract

A new generation of partially or even fully biodegradable implants is emerging. The idea of using temporary devices is to avoid a second surgery to remove the implant after its period of use, thereby improving considerably the patient's comfort and safety. This paper provides a state-of-the-art overview and an experimental section that describes the key technological challenges for making biodegradable devices. The general considerations for the design and synthesis of biodegradable components are illustrated with radiofrequency-driven resistor-inductor-capacitor (RLC ) resonators made of biodegradable metals (Mg, Mg alloy, Fe, Fe alloys) and biodegradable conductive polymer composites (polycaprolactone-polypyrrole, polylactide-polypyrrole). Two concepts for partially/fully biodegradable wireless implants are discussed, the ultimate goal being to obtain a fully biodegradable sensor for in vivo sensing.

New application of three‐dimensional printing biomaterial in nasal reconstruction

“…The superior rheological and viscoelastic properties render PCL easy to manufacture and manipulate into a large range of implants and devices. Coupled with relatively inexpensive production routes and U.S. Food and Drug Administration approval, this polymer provides a promising platform for the production of implants that may be manipulated physically, chemically, and biologically to possess tailorable degradation kinetics to suit a specific anatomical site . Several trials have demonstrated PCL‐based implants to have adequate structural integrity to withstand biomechanical loads over time .…”

Electrically conducting biodegradable polymer composites (polylactide‐polypyrrole and polycaprolactone‐polypyrrole) for passive resonant circuits

“…Real‐time access to in vivo physiological parameters is of great interest for medical doctors to observe the impact of drugs and treatments directly or to allow for efficient disease prevention by improved means for diagnosis. A promising concept presented in [1] is the development of wireless biomedical implants, which are biodegradable, including the electrical transmitter circuits. The benefit would be to avoid a second surgery to remove the implant after its period of use, a significant improvement for the patient's well‐being and safety.…”

Development of Electroplated Magnesium Microstructures for Biodegradable Devices and Energy Sources

“…Poly-L-lactic acid (PLLA) was selected as the encapsulation material for proof-of-concept because it is an FDA-approved, commercially-available, and well-studied biodegradable polymer. Microfabrication with PLLA has also garnered interest from the bioMEMS community in recent years [14], [18], [28]. It should be noted that alternative biodegradable polymers may be used for the embossing and encapsulation of Mg.…”

“…However, citric acid will also etch magnesium isotropically via an oxidative mechanism, which, ultimately, reduced the Mg thickness by 15% and increased surface roughness threefold [17]. Boutry et al utilized EDM to fabricate RLC resonators from 3-mm-thick commercial Mg that featured a width of 1 cm and a gap of 0.6 mm [14]- [18]. As shown, the bulk micromachining of commercial Mg is limited in minimum attainable feature size, amenability to three-dimensional multilayered structures, and post-process integration with other MEMS.…”