Experimental and theoretical photoluminescence studies in nucleic acid assembled gold-upconverting nanoparticle clusters

Abstract

Combinations of rare earth doped upconverting nanoparticles (UCNPs) and gold nanostructures are sought as nanoscale theranostics due to their ability to convert near infrared (NIR) photons into visible light and heat, respectively. However, because the large NIR absorption cross-section of the gold coupled with their thermo-optical properties can significantly hamper the photoluminescence of UCNPs, methods to optimize the ratio of gold nanostructures to UCNPs must be developed and studied. We demonstrate here nucleic acid assembly methods to conjugate spherical gold nanoparticles (AuNPs) and gold nanostars (AuNSs) to silica-coated UCNPs and probe the effect on photoluminescence. These studies showed that while UCNP fluorescence enhancement was observed from the AuNPs conjugated UCNPs, AuNSs tended to quench fluorescence. However, conjugating lower ratios of AuNSs to UCNPs led to reduced quenching. Simulation studies both confirmed the experimental results and demonstrated that the orientation and distance of the UCNP with respect to the core and arms of the gold nanostructures played a significant role in PL. In addition, the AuNS-UCNP assemblies were able to cause rapid gains in temperature of the surrounding medium enabling their potential use as a photoimaging-photodynamic-photothermal agent.

DNA‐Assembled Core‐Satellite Upconverting‐Metal–Organic Framework Nanoparticle Superstructures for Efficient Photodynamic Therapy

“…Herein, NaFY 4 :Yb/Er UCNPs were synthesized using a thermal decomposition method to produce monodisperse particles 23.8 ± 1.4 nm in diameter (Figure S8, Supporting Information) . The powder XRD pattern of the as‐prepared NaYF 4 ,Yb,Er UCNPs and selected area electron diffraction pattern further confirmed the UCNPs have a β‐phase crystalline structure (Figures S8 and S9, Supporting Information).…”

Tuning the Coupling in Single‐Molecule Heterostructures: DNA‐Programmed and Reconfigurable Carbon Nanotube‐Based Nanohybrids

“…As a proof of concept, we assembled individual single‐walled CNTs (SWCNTs) coupled to single colloidal semiconductor nanocrystals (Quantum Dots, QDs), chosen as model systems due to their tunable emissions and broad absorbances that further make them ideal candidates for novel light harvesting systems in photovoltaics and light emitting diodes;13 A bioinspired approach was pursued via the use of DNA as the linking moiety, due to its demonstrated ability to chemically program the assembly of nanoparticle‐based materials 14. In particular, we altered the number of bases in a double stranded (ds)DNA, in order to regulate the nanoscale distance between a SWCNT and a QD, in 1:1 nanohybrids.…”

Synthesis and Assembly of Click‐Nucleic‐Acid‐Containing PEG–PLGA Nanoparticles for DNA Delivery

“…CNAs are a recently reported synthetic analogs of DNA that are produced by photoinitiated thiolene chemistry . While synthetic polymers have been used to incorporate nucleobases for building assemblies and new materials, CNAs present a new class of nucleobase polymers that have the potential to be made with sequence control through thiol‐click reactions.…”