External stimuli-triggered photodynamic and sonodynamic therapies in combination with hybrid nanomicelles of ICG@PEP@HA: laser vs. ultrasound.

The concept of combining external medical stimuli with internal functional biomaterials to achieve cancer-oriented treatments is being emergingly developed. Optical and acoustical activations have shown particular promise as non-invasive regulation modalities in cancer treatment and intervention. It is always challenging to leverage the contributions of optical and acoustical stimuli and find appropriate biomaterials to optimally match them. Herein, a type of hybrid nanomicelle (ICG@PEP@HA) containing ICG as a photo/sonosensitizer, an amphiphilic peptide for membrane penetration and hyaluronic acid for cluster determinant 44 (CD44) targeting was fabricated. Triggered by the external stimuli of laser and US irradiation, their photo/sonothermal performance, in vitro reactive oxygen species (ROS) production capability and tumor-targeting efficiency have been systematically evaluated. It was interestingly found that the external stimulus of laser irradiation induced a greater quantity of ROS, which resulted in significant cell apoptosis and tumor growth inhibition in the presence of ICG@PEP@HA. The individual analyses and corresponding rationales have been investigated. Meanwhile, these hybrid nanomicelles were administered into MDA-MB-231 tumor-bearing nude mice for PDT and SDT therapies and their biocompatibility assessment, and a prevailing PDT efficacy and reliable bio-safety have been evidenced based on the hematological analysis and histochemical staining. In summary, this study has validated a novel pathway to utilize these hybrid nanomicelles for laser/US-triggered localized tumor treatment, and the treatment efficiency may be leveraged by different external stimuli sources. It is also expected to give rise to full accessibility to clinical translations for human cancer treatments by means of the as-reported laser/US-nanomicelle combination strategy.