Gold nanorods (GNRs) are versatile asymmetric nanoparticles with unique optical properties. These properties make GNRs ideal agents for applications such as photothermal cancer therapy, biosensing,... Show moreGold nanorods (GNRs) are versatile asymmetric nanoparticles with unique optical properties. These properties make GNRs ideal agents for applications such as photothermal cancer therapy, biosensing, and in vivo imaging. However, as-synthesised GNRs need to be modified with a biocompatible stabilising coating in order to be employed in these fields as the ligands used to stabilise GNRs during synthesis are toxic. An issue is that GNR performance in the aforementioned techniques can be affected by these modified coatings. For example if coatings are too thick then GNR entry into cells, or their sensitivity in sensing applications, can be compromised. Here we show that thiolated peptide amphiphiles (PAs) can act as GNR stabilisers and provide a thin and highly-stable coating under physiologically relevant conditions. Additionally, all tested PAs formed highly ordered (51.8-58.8% β-content), and dense (2.62-3.87 peptides per nm2) monolayers on the GNR surface. Moreover, the PA-coated GNRs demonstrated no cytotoxicity in vitro and, via injection in zebrafish embryos, the behavior and cellular interactions of such PA-coated GNRs were visualised in vivo, in real time, with two-photon (2P) microscopy. Show less
Surface charge plays a fundamental role in determining the fate of a nanoparticle, and any encapsulated contents, in vivo. Herein, we describe, and visualise in real time, light-triggered switching... Show moreSurface charge plays a fundamental role in determining the fate of a nanoparticle, and any encapsulated contents, in vivo. Herein, we describe, and visualise in real time, light-triggered switching of liposome surface charge, from neutral to cationic, in situ and in vivo (embryonic zebrafish). Prior to light activation, intravenously administered liposomes, composed of just two lipid reagents, freely circulate and successfully evade innate immune cells present in the fish. Upon in situ irradiation and surface charge switching, however, liposomes rapidly adsorb to, and are taken up by, endothelial cells and/or are phagocytosed by blood resident macrophages. Coupling complete external control of nanoparticle targeting together with the intracellular delivery of encapsulated (and membrane impermeable) cargos, these compositionally simple liposomes are proof that advanced nanoparticle function in vivo does not require increased design complexity but rather a thorough understanding of the fundamental nano-bio interactions involved. Surface charge plays an important role in determining nanoparticle fate in vivo. Here the authors report on the development of a light triggered charge switching liposome and demonstrate light triggered liposome targeting, uptake and payload delivery in a zebrafish model. Show less
Surface charge plays a fundamental role in determining the fate of a nanoparticle, and any encapsulated contents, in vivo. Herein, we describe, and visualise in real time, light-triggered switching... Show moreSurface charge plays a fundamental role in determining the fate of a nanoparticle, and any encapsulated contents, in vivo. Herein, we describe, and visualise in real time, light-triggered switching of liposome surface charge, from neutral to cationic, in situ and in vivo (embryonic zebrafish). Prior to light activation, intravenously administered liposomes, composed of just two lipid reagents, freely circulate and successfully evade innate immune cells present in the fish. Upon in situ irradiation and surface charge switching, however, liposomes rapidly adsorb to, and are taken up by, endothelial cells and/or are phagocytosed by blood resident macrophages. Coupling complete external control of nanoparticle targeting together with the intracellular delivery of encapsulated (and membrane impermeable) cargos, these compositionally simple liposomes are proof that advanced nanoparticle function in vivo does not require increased design complexity but rather a thorough understanding of the fundamental nano-bio interactions involved. Show less
