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Abstract: CRISPR/Cas9 system is a powerful toolbox for gene editing. However, the low delivery efficiency is still a big hurdle impeding its applications. Herein, we report a strategy to deliver Cas9‐sgPlk‐1 plasmids (CP) by a multifunctional vehicle for tumor therapy. We condensed CPs on TAT peptide‐modified Au nanoparticles (AuNPs/CP, ACP) via electrostatic interactions, and coated lipids (DOTAP, DOPE, cholesterol, PEG2000‐DSPE) on the ACP to form lipid‐encapsulated, AuNPs‐condensed CP (LACP). LACP can enter tumor cells and release CP into the cytosol by laser‐triggered thermo‐effects of the AuNPs; the CP can enter nuclei by TAT guidance, enabling effective knock‐outs of target gene (Plk‐1) of tumor (melanoma) and inhibition of the tumor both in vitro and in vivo. This AuNPs‐condensed, lipid‐encapsulated, and laser‐controlled delivery system provides a versatile method for high efficiency CRISPR/Cas9 delivery and targeted gene editing for treatment of a wide spectrum of diseases. [ABSTRACT FROM AUTHOR]

The aspect ratio (AR) is one of the most intriguing parameters of gold nanorods (GNRs), which plays an important role in determining localized surface plasmon (LSPR) properties. Instead of conventional imaging techniques, the optical extinction spectroscopy (OES) method has been developed for allowing fast statistically measuring the average AR under static approximation. In this work, combining with the previous achievements in spectroscopic technique, we further analyze the effects of gold dielectric function and near distance dielectric sensitivity. The former may reflect possible dielectric loss of real Au samples from ideal single crystalline. The latter reflects the cetyltrimethylammonium bromide (CTAB) adsorption on the surface of GNR induces different LSPR shifts below and above critical micelle concentration (CMC). However, their effect on the determination of AR has not been evaluated in OES method. The average AR measurements as a function of absorbance of CTAB-GNRs and LSPR maximum below the CMC were studied. Our results indicate that after considering these factors, the mean ARs obtained from spectroscopic techniques are closer to those obtained from imaging techniques. [ABSTRACT FROM AUTHOR]

With great advances in wet chemical synthesis of nanoparticles (NPs), plasmonic NPs with various sizes and morphologies are easily available nowadays and demonstrate great potentials in optical, electronic, and biomedical applications. Plasmonic circular dichroism (CD), relating to circular dichroism responses at localized surface plasmon resonance of metal nanostructures, has emerged as a research direction of plasmonics with promising prospects in enantioselective catalysis, chiral separation, and ultrasensitive detections. Herein, plasmonic CD responses of gold nanoparticle based nanostructures are summarized. Two kinds of plasmonic CD phenomena are investigated: structural CD and induced CD. Structural CD is the response from chiral assemblies composed of plasmonic NPs with strong dipole–dipole interactions. Induced CD is the response of nonchiral plasmonic NPs with chiral molecules attached at surface. The weak CD is the result of Coulomb interaction between chiral molecules and plasmonic NPs. Efforts on how to achieve strong CD signals for these two configurations by using chiral molecules and Au nanoparticles are reported. The fabrication of chiral nanostructures, tuning and amplification of CD responses, CD‐based biosensors, chiral catalysis, and future perspectives are presented. The importance of the shape anisotropy of gold nanorods in the generation and amplification of CD signals is especially highlighted. [ABSTRACT FROM AUTHOR]

Au@Cu2O core–shell nanostructures are fabricated to havea plasmon enhancement effect using Au nanorods (Au NRs) as a plasmon-tailorablecore. By varying the concentration of Au NRs, we can tune the shellthickness in the range of 10–25 nm. The shell is composed ofCu2O nanocrystallites. Because of the thin shells, theextinction spectra at wavelength >500 nm are dominated by the Aucore. However, the large dielectric constant of the shell causes anobvious red shift of the surface plasmon resonance (SPR) band of theAu nanorod. Besides, transverse octupolar SPR appears as a resultof the anisotropy of the core and the high dielectric constant ofthe shell. The anisotropic geometry of the Au NR is found to supportthe octupolar resonances at smaller sizes than for their sphericalcounterpart. Theoretical simulations indicate that the transverseSPR bands are divided into two resonances, which are dipolar- andoctupolar-dominant, respectively. The Cu2O shell degradesvia a defect-mediated oxidative pathway, which is aggravated uponlongitudinal SPR excitation. The SPR-mediated local field enhancementand resonance energy transfer are found to enhance the excitationof the defect states in the shell, thus providing a simple yet selectiveprobing strategy for defect states. [ABSTRACT FROM AUTHOR]

Growthkinetics plays an important role in the shape control ofnanocrystals (NCs). Herein, we presented a unique way to fine-tunethe growth kinetics via oxidative etching activated by copper ions.For the overgrowth of gold nanorods (Au NRs), competitive adsorptionof dissolved oxygen on rod surface was found to slow down the overgrowthrate. Copper ions were able to remove the adsorbed oxygen speciesfrom the Au surface via oxidative etching, thus exposing more reactionsites for Au deposition. In this way, copper ions facilitated theovergrowth process. Furthermore, Cu2+rather than Cu+acted as the catalyst for the oxidative etching. Comparativestudy with Ag+indicated that Cu2+cannot regulateNC shapes via an underpotential deposition mechanism. In contrast,Ag+led to the formation of Au tetrahexahedra (THH) anda slight decrease of the growth rate at similar growth conditions.Combining the distinct roles of the two ions enabled elongated THHto be produced. Copper ions activating the O2pathway suggestedthat dissolved oxygen has a strong affinity for the Au surface. Moreover,the results of NC-sensitized singlet oxygen (1O2) indicated that the absorbed oxygen species on the surface of AuNCs bounded with low-index facets mainly existed in the form of molecularO2. [ABSTRACT FROM AUTHOR]