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Laser therapies can provide a minimally invasive treatment alternative to surgical resection of tumors. However, the
effectiveness of these therapies is limited due to nonspecific heating of target tissue which often leads to healthy tissue
injury and extended treatment durations. These therapies can be further compromised due to heat shock protein (HSP)
induction in tumor regions where non-lethal temperature elevation occurs, thereby imparting enhanced tumor cell
viability and resistance to subsequent chemotherapy and radiation treatments. Introducing multi-walled nanotubes
(MWNT) into target tissue prior to laser irradiation increases heating selectivity permitting more precise thermal energy
delivery to the tumor region and enhances thermal deposition thereby increasing tumor injury and reducing HSP
expression induction. This study investigated the impact of MWNT inclusion in untreated and laser irradiated monolayer
cell culture and cell phantom model. Cell viability remained high for all samples with MWNT inclusion and cells
integrated into alginate phantoms, demonstrating the non-toxic nature of both MWNTs and alginate phantom models.
Following, laser irradiation samples with MWNT inclusion exhibited dramatic temperature elevations and decreased cell
viability compared to samples without MWNT. In the cell monolayer studies, laser irradiation of samples with MWNT
inclusion experienced up-regulated HSP27, 70 and 90 expression as compared to laser only or untreated samples due to
greater temperature increases albeit below the threshold for cell death. Further tuning of laser parameters will permit
effective cell killing and down-regulation of HSP. Due to optimal tuning of laser parameters and inclusion of MWNT in
phantom models, extensive temperature elevations and cell death occurred, demonstrating MWNT-mediated laser
therapy as a viable therapy option when parameters are optimized. In conclusion, MWNT-mediated laser therapies show
great promise for effective tumor destruction, but require determination of appropriate MWNT characteristics and laser
parameters for maximum tumor destruction.
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