Gold-Bipyramid-Based Nanothernostics: FRET-Mediated Protein-Specific Sialylation Visualization and Oxygen-Augmenting Phototherapy against Hypoxic Tumor.

Abstract

Despite several attempts, incorporating biological detection that supplies necessary biological information into therapeutic nanotheranostics for hypoxic tumor treatments is considered to be in its infancy. It is therefore imperative to consolidate biological detection and desirable phototherapy into a single nanosystem for maximizing theranostic advantages. Herein, we develop a versatile nanoprobe through combined fluorescence resonance energy transfer (FRET) and oxygen-augmenting strategy, namely APT, which enables glycosylation detection, O2 self-sufficiency, and collaborative phototherapy. Such APT nanoprobes were constructed by depositing platinum onto gold nano-bipyramids (Au NBPs), linking FITC fluorophore-labeled AS1411 aptamers for introducing FRET donors, and by conjugating G-quadruplex intercalated with TMPyP4 to their surfaces via the SH-DNA chain. By installing FRET acceptors on the glycan of targeted EpCAM glycoprotein using the metabolic glycan labeling and click chemistry, FRET signals appear on the cancerous cell membranes, not normal cells, when donors and acceptors are within an appropriate distance. This actualizes protein-specific glycosylation visualization while revealing glycan-based changes correlated with tumor progression. Interestingly, the deposited platinum scavenges excessive H2O2 as artificial nanoenzymes to transform O2 that alleviates tumor hypoxia and simultaneously elevates singlet oxygen (1O2) for inducing cancer cell apoptosis. Notably, the significant hyperthermia devastation was elicited via APT nanoprobes with phenomenal photothermal therapy (PTT) efficiency (71.8%) for thermally ablating cancer cells, resulting in synergistically enhanced photodynamic-hyperthermia therapy. Consequently, APT nanoprobes nearly actualized thorough tumor ablation while demonstrating highly curative biosafety. This work offers a new paradigm to rationally explore a combined FRET and oxygen-augmenting strategy with a focus on nanotheranostics for hypoxic tumor elimination.