Plasmonic nanoparticles and nucleic acids hybrids for targeted gene delivery,bioimaging,and molecular recognition

Promising biomedical applications of hybrid materials composed of gold nanoparticles and nucleic acids have attracted strong interest from the nanobiotechnological community.The particular interest is owing to the robust and easy-to-make synthetic approaches,to the versatile optical and catalytic properties of gold nanoparticles combined with the molecular recognition and programmable properties of nucleic acids.The significant progress is made in the develop-ment of DNA-gold nanostructures and their applications,such as molecular recognition,cell and tissue bioimaging,targeted delivery of therapeutic agents,etc.This review is focused on the critical discussion of the recent applications of the gold nanoparticles-nucleic acids hybrids.The effect of particle size,surface,charge and thermal properties on the interactions with functional nucleic acids is discussed.For each of the above topics,the basic principles,recent advances,and current challenges are discussed.Emphasis is placed on the systematization of data over the theranostic systems on the basis of the gold nanoparticles-nucleic acids hybrids.Specifically,we start our discussion with observation of the recent data on interaction of various gold nano-particles with nucleic acids.Further we describe existing gene delivery systems,nucleic acids detection,and bioimaging technologies.Finally,we describe the phenomenon of the polymerase chain reaction improvement by gold nanoparticle additives and its potential underlying mechanisms.Lastly,we provide a short summary of reported data and outline the challenges and perspectives.

Au-nanocluster-loaded human serum albumin nanoparticles with enhanced cellular uptake for fluorescent imaging

Protein-directed fluorescent Au nanoclusters have been widely studied owing to their potential applications in sensing,imaging,and drug and gene delivery.However,the use of nanoclusters in drug delivery is limited by low cellular uptake.In this study,human serum albumin-directed Au nanoclusters served as building blocks to obtain protein nanoparticles by desolvation.The nanoparticles had a decent quantum yield(QY),high colloidal stability and low cytotoxicity,and they could be readily conjugated with biological molecules.The cellular uptake of the Au nanoclusters and nanocluster-loaded protein nanoparticles were studied by confocal fluorescence microscopy.Agglomeration of the protein-directed Au nanoclusters into 50–150-nm nanoparticles dramatically increased the cellular uptake.

Introduction to the special issue on surface-enhanced Raman spectroscopy and functionalized plasmonic nanoparticles for biomedical applications

Since its first discovery in 1974 from the enhanced Raman spectra of pyridine molecules on roughened silver surface,surface-enhanced Raman spectrosco-py(SERS)has garnered significant attention in the field of chemistry,biology,and medicine.With the sensitivity of down to single-molecule level and the intrinsic"fingerprint"spectrum,SERS enables the ultra-sensitive,specific,selective,and multi-plexing label-free analysis of a trace of molecules in aqueous biological environments,minus the inter-ference from water,white-light or tissue auto-fluorescence background.

Gold nanorods with a hematoporphyrin-loaded silica shell for dual-modality photodynamic and photothermal treatment of tumors in vivo

Nanocomposites （NCs） consisting of a gold nanorod core and a mesoporous silica shell doped with hematoporphyrin （HP） have been fabricated in order to improve the efficiency of cancer treatment by combining photothermal and photodynamic therapies （PDT ＋ PTT） in vivo. In addition to the long-wavelength plasmon resonance near 810-830 nm, the fabricated NCs exhibited a 400-nm absorbance peak corresponding to bound HP, generated singlet oxygen under 633-nm excitation near the 632.5-nm Q-band, and produced heat under a 808-nm near-infrared （NIR） laser irradiation. These modalities were used for a combined PDT ＋ PTT treatment of large （about 3 cm3） solid tumors in vivo with a xenorafted tumor rat model. NCs were directly injected into tumors and irradiated simultaneously with 633-nm and 808-nm lasers to stimulate the combined photodynamic and photothermal activities of NCs. The efficiency of the combined therapy was evaluated by optical coherence tomography, histological analysis, and by measurements of the tumor volume growth during a 21-day period. The NC-mediated PDT led to weak changes in tissue histology and to a moderate 20% decrease in the tumor volume. In contrast, the combined PDT ＋ PTT treatment resulted in the large-area tumor necrosis and led to dramatic decrease in the tumor volume.