Amplified Photoacoustic Signal and Enhanced Photothermal Conversion of Polydopamine-Coated Gold Nanobipyramids for Phototheranostics and Synergistic Chemotherapy.

Light-responsive nanoprobes were suffering from the threat of high-dose laser irradiation, and it was important for constructing new nanoprobes for safe and efficient phototheranostics. Here, polydopamine (PDA)-coated gold nanobipyramids (AuNBPs@PDA) were synthesized for amplified photoacoustic (PA) signal and enhanced photothermal conversion with low-dose laser irradiation and then doxorubicin (DOX)-loaded AuNBPs@PDA-DOX nanoprobes were constructed for PA imaging-guided synergistic photothermal therapy (PTT) and chemotherapy. The AuNBPs@PDA nanoparticles possessed higher photothermal conversion efficiency (42.07%) and stronger PA signal than those of AuNBP nanoparticles, and the AuNBPs@PDA-DOX nanoprobes showed dual-responsive DOX release of pH and photothermal stimulation. With low-dose laser irradiation (1.0 W/cm2) and low-concentration AuNBPs@PDA-DOX (60 µg/mL), the 4T1 cell viability was reduced to about 5%, owing to the combination of PTT and chemotherapy, compared with 42.3% of single chemotherapy and 25.3% of single PTT. Moreover, by modeling 4T1 tumor-bearing nude mice, in vivo PA imaging was achieved and the tumors were completely inhibited, demonstrating the excellent synergistic effect of PTT/chemotherapy. Therefore, the developed AuNBPs@PDA-DOX nanoprobes can be used for phototheranostics and synergistic chemotherapy, achieving low-dose laser irradiation and high-efficient visualized theranostics.

Ce6/Mn2+-chelated polydopamine@black-TiO2 nanoprobes for enhanced synergistic phototherapy and magnetic resonance imaging in 4T1 breast cancer.

Black titanium dioxide (TiO2) nanoparticles have attracted great attention due to their application in photothermal therapy (PTT). However, single-mode phototherapy has the risk of recurrence, and the high-dose laser usually imposed to improve the PTT performance can bring a potential threat to security. Here, polydopamine (PDA)-coated black TiO2 (b-P25@PDA) nanoparticles with a core-shell structure were synthesized for enhanced PTT; then, synergistic phototherapy nanoprobes (b-P25@PDA-Ce6 (Mn)) were constructed by coupling chlorin e6 (Ce6) and chelating Mn2+ for simultaneous photodynamic therapy (PDT)/PTT and magnetic resonance (MR) imaging, in which a low-dose laser was used and imaging-guided phototherapy with high efficiency and high safety was achieved. The prepared nanoprobes showed high photothermal conversion efficiency (32.12%), high reactive oxygen generation and excellent MR imaging. In the 4T1 tumor-bearing nude mouse model, the tumors completely disappeared under the combination of PDT/PTT with a low-dose laser but were only partially inhibited by single PDT and single PTT. The current work developed a multifunctional black TiO2-based nanoprobe for enhanced synergistic PDT/PTT and MR imaging, which will be important for the safe and efficient visualized theranostics of cancers.

ZD2-Engineered Gold Nanostar@Metal-Organic Framework Nanoprobes for T1 -Weighted Magnetic Resonance Imaging and Photothermal Therapy Specifically Toward Triple-Negative Breast Cancer.

Compared with other subtypes of breast cancer, triple-negative breast cancer (TNBC) is seriously threatening to human life. Therefore, it is a matter of urgency to develop multifunctional nanoprobes for visualized theranostics of TNBC, achieving specific targeting toward only TNBC, but not other subtypes. Nanoscale metal-organic frameworks (MOFs) show important potential in visualized theranostics of tumors, but it is critical to synthesize well-defined core-shell MOF-based nanocomposites by encapsulating a single nanoparticle within MOF. In this study, a TNBC-targeted peptide (ZD2)-engineered, and a single gold nanostar (AuNS) coated within MIL-101-NH2 (Fe) by coating MOF with four cycles, obtain well-defined core-shell AuNS@MOF-ZD2 nanocomposites, which are expected to achieve T1 -weighted magnetic resonance imaging and photothermal therapy (PTT) specifically targeting toward TNBC. The prepared AuNS@MOF-ZD2 nanocomposites possess good biocompatibility, efficient T1 -weighted magnetic resonance (MR) relaxivity and stable photothermal conversion ability with an efficiency of 40.5%. The in vitro and in vivo characterizations prove their performances of T1 -weighted MR and PTT with a low power density of 808 nm laser, achieving excellent theranostic efficacy in TNBC. Importantly, it is demonstrated that the prepared AuNS@MOF-ZD2 nanoprobes can specifically target TNBC cells (MDA-MB-231), but not other subtypes of breast cancer cells (MDA-MB-435, MDA-MB-468, and MCF-7), indicating their promising application in visualized theranostics of breast cancers with molecular classification.