Assessment of Embedded Conjugated Polymer Sensor Arrays for Potential Load Transmission Measurement in Orthopaedic Implants

Abstract

Load transfer through orthopaedic joint implants is poorly understood. The longer-term outcomes of these implants are just starting to be studied, making it imperative to monitor contact loads across the entire joint implant interface to elucidate the force transmission and distribution mechanisms exhibited by these implants in service. This study proposes and demonstrates the design, implementation, and characterization of a 3D-printed smart polymer sensor array using conductive polyaniline (PANI) structures embedded within a polymeric parent phase. The piezoresistive characteristics of PANI were investigated to characterize the sensing behaviour inherent to these embedded pressure sensor arrays, including the experimental determination of the stable response of PANI to continuous loading, stability throughout the course of loading and unloading cycles, and finally sensor repeatability and linearity in response to incremental loading cycles. This specially developed multi-material additive manufacturing process for PANI is shown be an attractive approach for the fabrication of implant components having embedded smart-polymer sensors, which could ultimately be employed for the measurement and analysis of joint loads in orthopaedic implants for in vitro testing.

Multifunctional electromechanical and thermoelectric polyaniline–poly(vinyl acetate) latex composites for wearable devices

“…The literature, presents several examples of PANI blending with several host matrices such as poly(n-butyl methacrylate) (PBMA) [13], poly(dimethysiloxe) (PMDS) [11], styrene-butadiene-styrene copolymer (SBS) [14,15] or poly(ethylene-vinyl acetate) (PVAc) [16] with promising piezoresistive behaviour for deformation sensors [17]. By contrast, fewer studies have been reported about PANI composites used in the fabrication of flexible temperature sensors [2].…”

Implants with Sensing Capabilities

“…To analyze loads in orthopedic implants, a three-dimensionally (3D)-printed sensor array (composed of PANI structures embedded in a polymeric parent phase) was developed. , Linear outputs following fractional changes in resistance occurring during incrementally applied loads, were obtained. For the detection of micromotion, eddy current sensors and factors that affect the sensitivity and range of sensors implanted in the tibia beneath the metallic plate were also investigated .…”

Additive Manufacturing in Total Joint Arthroplasty

“…In the same work, challenges related to the development of such implants are discussed, highlighting the need for collaboration among stakeholders to realize these novel applications. For in situ measurements of implant performance, Micolini and colleagues 40 demonstrated the use of AM to fabricate a polymer sensor array with conductive polyaniline that can be embedded into implants for in-situ measurement of load transmission. Besides that, AM is also being used as a prototyping tool for testing new research approaches.…”