Light-Induced Reversible DNA Ligation of Gold Nanoparticle Superlattices

DNA-mediated self-assembly of nanoparticles has been of great interest because it enables access to nanoparticle superstructures that cannot be synthesized otherwise. However, the programmability of higher order nanoparticle structures can be easily lost under DNA denaturing conditions. Here, we demonstrate that light can be employed as an external stimulus to master the stability of nanoparticle superlattices (SLs) via the promotion of a reversible photoligation of DNA in SLs. The oligonucleotides attached to the nanoparticles are encoded to ligate using 365 nm light, effectively locking the SLs and rendering them stable under DNA denaturing conditions. The reversible process of unlocking these structures is possible by irradiation with light at 315 nm, recovering the structures to their natural state. Our work inspires an alternative research direction toward postassembly manipulation of nanoparticle superstructures using external stimuli as a tool to enrich the library of additional material forms and their application in different media and environments

Modulating Pharmacokinetics, Tumor Uptake and Biodistribution by Engineered Nanoparticles

Inorganic nanoparticles provide promising tools for biomedical applications including detection, diagnosis and therapy. While surface properties such as charge are expected to play an important role in their in vivo behavior, very little is known how the surface chemistry of nanoparticles influences their pharmacokinetics, tumor uptake, and biodistribution.Using a family of structurally homologous nanoparticles we have investigated how pharmacological properties including tumor uptake and biodistribution are influenced by surface charge using neutral (TEGOH), zwitterionic (Tzwit), negative (TCOOH) and positive (TTMA) nanoparticles. Nanoparticles were injected into mice (normal and athymic) either in the tail vein or into the peritoneum.Neutral and zwitterionic nanoparticles demonstrated longer circulation time via both i.p. and i.v. administration, whereas negatively and positively charged nanoparticles possessed relatively short half-lives. These pharmacological characteristics were reflected on the tumor uptake and biodistribution of the respective nanoparticles, with enhanced tumor uptake by neutral and zwitterionic nanoparticles via passive targeting

Directed organization of gold nanoparticles in polymer coatings through infrared-assisted evaporative lithography

Infrared-assisted evaporative lithography (IRAEL) is presented as an emerging technology to direct the assembly of gold nanospheres (AuNSs) into large-scale superstructures within colloidal polymeric coatings. The organization of gold nanoparticle arrays within the superstructures can be tuned over length scales, ranging from micrometers up to several millimetres, giving rise to intrinsic plasmonic properties. © 2013 The Royal Society of Chemistry

The sedimentation of colloidal nanoparticles in solution and its study using quantitative digital photography

Sedimentation and diffusion are important aspects of the behavior of colloidal nanoparticles in solution, and merit attention during the synthesis, characterization, and application of nanoparticles. Here, the sedimentation of nanoparticles is studied quantitatively using digital photography and a simple model based on the Mason–Weaver equation. Good agreement between experimental time‐lapse photography and numerical solutions of the model is found for a series of gold nanoparticles. The new method is extended to study for the first time the gravitational sedimentation of DNA‐linked gold nanoparticle dimers as a model system of a higher complexity structure. Additionally, simple formulas are derived for estimating suitable parameters for the preparative centrifugation of nanoparticle solutions

The sedimentation of colloidal nanoparticles in solution and its study using quantitative digital photography

Sedimentation and diffusion are important aspects of the behavior of colloidal nanoparticles in solution, and merit attention during the synthesis, characterization, and application of nanoparticles. Here, the sedimentation of nanoparticles is studied quantitatively using digital photography and a simple model based on the Mason–Weaver equation. Good agreement between experimental time‐lapse photography and numerical solutions of the model is found for a series of gold nanoparticles. The new method is extended to study for the first time the gravitational sedimentation of DNA‐linked gold nanoparticle dimers as a model system of a higher complexity structure. Additionally, simple formulas are derived for estimating suitable parameters for the preparative centrifugation of nanoparticle solutions

Selective killing of cells triggered by their mRNA signature in the presence of smart nanoparticles.

The design of nanoparticles that can selectively perform multiple roles is of utmost importance for the development of the next generation of nanoparticulate drug delivery systems. So far most research studies are focused on the customization of nanoparticulate carriers to maximize their drug loading, enhance their optical signature for tracking in cells or provide photo-responsive effects for therapeutic purposes. However, a vital requirement of the new generation of drug carriers must be the ability to deliver their payload selectively only to cells of interest rather than the majority of various cells in the vicinity. Here we show for the first time a new design of nanoparticulate drug carriers that can specifically distinguish different cell types based on their mRNA signature. These nanoparticles sense and efficiently kill model tumour cells by the delivery of an anti-cancer drug but retain their payload in cells lacking the specific mRNA target

Selective killing of cells triggered by their mRNA signature in the presence of smart nanoparticles.

The design of nanoparticles that can selectively perform multiple roles is of utmost importance for the development of the next generation of nanoparticulate drug delivery systems. So far most research studies are focused on the customization of nanoparticulate carriers to maximize their drug loading, enhance their optical signature for tracking in cells or provide photo-responsive effects for therapeutic purposes. However, a vital requirement of the new generation of drug carriers must be the ability to deliver their payload selectively only to cells of interest rather than the majority of various cells in the vicinity. Here we show for the first time a new design of nanoparticulate drug carriers that can specifically distinguish different cell types based on their mRNA signature. These nanoparticles sense and efficiently kill model tumour cells by the delivery of an anti-cancer drug but retain their payload in cells lacking the specific mRNA target

Peptide-coated gold nanoparticles for modulation of angiogenesis in vivo

Catarina Roma-Rodrigues,1 Amelie Heuer-Jungemann,2 Alexandra R Fernandes,1 Antonios G Kanaras,2 Pedro V Baptista1 1UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal; 2Institute for Life Sciences, Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, UK Abstract: In this work, peptides designed to selectively interact with cellular receptors involved in the regulation of angiogenesis were anchored to oligo-ethylene glycol-capped gold nanoparticles (AuNPs) and used to evaluate the modulation of vascular development using an ex ovo chick chorioallantoic membrane assay. These nanoparticles alter the balance between naturally secreted pro- and antiangiogenic factors, under various biological conditions, without causing toxicity. Exposure of chorioallantoic membranes to AuNP–peptide activators of angiogenesis accelerated the formation of new arterioles when compared to scrambled peptide-coated nanoparticles. On the other hand, antiangiogenic AuNP–peptide conjugates were able to selectively inhibit angiogenesis in vivo. We demonstrated that AuNP vectorization is crucial for enhancing the effect of active peptides. Our data showed for the first time the effective control of activation or inhibition of blood vessel formation in chick embryo via AuNP-based formulations suitable for the selective modulation of angiogenesis, which is of paramount importance in applications where promotion of vascular growth is desirable (eg, wound healing) or ought to be contravened, as in cancer development. Keywords: angiogenesis activators, antiangiogenic, CAM assay, gold nanoparticles, peptide-coated gold nanoparticles, vascular developmen

Spectroscopic and hydrodynamic characterisation of DNA‐linked gold nanoparticle dimers in solution using two‐photon photoluminescence

Two‐photon photoluminescence (TPPL) emission spectra of DNA–gold nanoparticle (AuNP) monoconjugates and the corresponding DNA‐linked AuNP dimers are obtained by photon time‐of‐flight spectroscopy. This technique is combined with two‐photon photoluminescence fluctuation correlation spectroscopy (TPPL–FCS) to simultaneously monitor the optical and hydrodynamic behaviour of these nano‐assemblies in solution, with single‐particle sensitivity and microsecond temporal resolution. In this study, the AuNPs have an average core diameter of 12 nm, which renders their dark‐field plasmonic light scattering too weak for single‐particle imaging. Moreover, as a result of the lack of plasmonic coupling in the dimers, the optical extinction, scattering and photoluminescence spectra of the DNA–AuNP complexes are not sufficiently different to distinguish between monomers and dimers. The use of TPPL–FCS successfully addresses these bottlenecks and enables the distinction between AuNP monomers and AuNP dimers in solution by measurement of their hydrodynamic rotational and translational diffusion