Strategies for non‐invasive imaging of polymeric biomaterial in vascular tissue engineering and regenerative medicine using ultrasound and photoacoustic techniques

Abstract

The ability of new polymeric materials to provide excellent biomechanical properties expanded their potential for biomedical applications enormously. The use of non-invasive imaging modalities could provide crucial information to monitor the efficacy/effectiveness/efficiency of the new materials employed in 'regenerative' approaches, including scaffolds, hydrogels, self-assembling materials and nanosized structures. The assessment of the morpho-functional and metabolic changes of treated or implanted tissues, the visualization of sites of drug delivery and the real-time check of the in vivo efficacy of therapeutics could be achieved by non-invasive micro-and macro-imaging techniques. The macro-and nano-requirements of these new materials and their behaviour in vivo can be investigated using standard approaches such as computed tomography, MRI and ultrasound techniques and the emerging photoacoustic imaging. This paper presents recent advancements of ultrasonography and the novel photoacoustic technique to monitor the morpho-functional parameters of synthetic polymeric scaffolds and conduits in experimental models.

Enhanced Photoacoustic Signal of Passion Fruit-Like Nanoarchitectures in a Biological Environment

“…The development of noninvasive techniques for diagnostic purposes is a crucial step toward the reduction of patient’s pain, health risks, and social costs. In this context, photoacoustic imaging (PAI) plays a pivotal role, allowing quick in vivo morphological, functional, and molecular information to be obtained. − …”

In Vivo Tracking of Tissue Engineered Constructs

“…For this method, the pulsed laser energy causes heat-induced, elastic tissue expansion, of which emits ultrasonic waves in the MHz range. Via ultrasound transducers, these waves are detected and electronically processed to output a final picture (Figure 11) [132]. PAI diverges based on the acquisition method into photoacoustic microscopy (PAM—focused scanning) and photoacoustic tomography (PACT—inverse reconstruction) [133].…”

“…The advantages of PAI include its non-invasiveness, non-destructiveness, macro to microscale versatility, and compatibility with established imaging modalities. Conversely, PAI challenges include merging optical and acoustic signals, limited scanning speed for wide fields of motion and optimized mathematical models across measurement scales [132,133].…”

Recent progress in photoacoustic molecular imaging

“…As PAT draws increasing attention from the biomedical community at large, more and more molecular probes are being developed specifically for PAT by researchers in synthetic chemistry, protein engineering, and nanotechnology. The availability of commercial PAT systems has also accelerated the adoption of these molecular probes in fundamental research areas, including cancer biology [8, 31, 33, 35, 39, 45, 85, 86], neuroscience [87–90], and regenerative medicine [91–94]. …”