Sodium alginate-based tissue-mimicking phantom with tunable optical properties for laser thermotherapy

In the laser ablation and thermal therapy technologies, tissue-mimicking phantoms (TMPs) play a crucial role, enabling both the preclinical testing and equipment calibration, without the use of biological tissues. Special attention is paid to the simultaneous replication of optical, thermal, and mechanical properties of target tissues in a single TMP. Sodium alginate forms a promising material platform for the TMP development due to the tunability of its physical properties, biocompatibility, and exceptional thermal stability. Indeed, as a polysaccharide derived from brown seaweed, sodium alginate forms hydrogels (through the ionic cross-linking) with controllable mechanical and optical properties, and tailored texture and structural integrity. In this paper, the alginate-based TMP loaded by CuSO₄, as an absorptive component, and ovalbumin, as a scattering component that also models the thermal coagulation of proteins, is judiciously designed to capture the key optical, thermal, and mechanical properties of tissues. To make its applications in studies of the laser coagulation and ablation of hepatocellular carcinoma (HCC) of the liver possible, a case example of such a TMP is considered, which models the liver tissues at the 1064 nm wavelength. The experimental studies involving exposure of TMP to laser radiation demonstrate that it offers controlled coagulation thresholds and enables visualization of the heat-induced tissue damage through the reversible or irreversible phase transitions. Our findings uncover the potential of the developed TMP in laser thermotherapy technologies.