In Vivo Imaging of Biodegradable Implants and Related Tissue Biomarkers

Abstract

Non-invasive longitudinal imaging of osseointegration of bone implants is essential to ensure a comprehensive, physical and biochemical understanding of the processes related to a successful implant integration and its long-term clinical outcome. This study critically reviews the present imaging techniques that may play a role to assess the initial stability, bone quality and quantity, associated tissue remodelling dependent on implanted material, implantation site (surrounding tissues and placement depth), and biomarkers that may be targeted. An updated list of biodegradable implant materials that have been reported in the literature, from metal, polymer and ceramic categories, is provided with reference to the use of specific imaging modalities (computed tomography, positron emission tomography, ultrasound, photoacoustic and magnetic resonance imaging) suitable for longitudinal and non-invasive imaging in humans. The advantages and disadvantages of the single imaging modality are discussed with a special focus on preclinical imaging for biodegradable implant research. Indeed, the investigation of a new implant commonly requires histological examination, which is invasive and does not allow longitudinal studies, thus requiring a large number of animals for preclinical testing. For this reason, an update of the multimodal and multi-parametric imaging capabilities will be here presented with a specific focus on modern biomaterial research.

Biodegradable Polyurethane Scaffolds in Regeneration Therapy: Characterization and In Vivo Real-Time Degradation Monitoring by Grafted Fluorescent Tracer

“…Since biodegradable implants are essentially designed to be part of the human body, they should be biochemically neutral, nontoxic, and not provoke adverse reactions . The same characteristics should be true for their degradation products.…”

“…Since biodegradable implants are essentially designed to be part of the human body, they should be biochemically neutral, nontoxic, and not provoke adverse reactions. 56 The same characteristics should be true for their degradation products. Therefore, liquid chromatography−mass spectrometry (LC-MS), which helps to identify the chemicals, was further used to analyze the decomposed components of the PUs during degradation.…”

Beyond Tissue replacement: The Emerging role of smart implants in healthcare

“…Most studies of permanent non-biodegradable implants are accompanied by inflammatory reactions [ 259 ]. Chronic inflammation, characterized by long-lasting immune responses, is generally not observed with biodegradable implants [ 260 ]. It is important to note that the extent of the inflammatory response can vary depending on the specific material composition, the implant's interaction with the biological environment, and individual variations in immune responses.…”

Gamete-exporting organs of vertebrates: dazed and confused

“…Researchers can utilize the same organism at various developmental time points. Multiple noninvasive imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and ultrasound (US), are available (see https://encyclopedia.pub/entry/12494; Riehakainen et al, 2021). It is preferable to avoid the use of radioactive tracers or heavy molecular dyes.…”