ABSTRACT
Cellular imaging technologies employing metallic surface-enhanced Raman scattering (SERS) tags have gained much interest toward clinical diagnostics, but they are still suffering from poor controlled distribution of hot spots and reproducibility of SERS signals. Here, we report the fabrication and characterization of high narrow nanogap-containing Au@Au core-shell SERS nanoparticles (GCNPs) for the identification and imaging of proteins overexpressed on the surface of cancer cells. First, plasmonic nanostructures are made of gold nanoparticles (â¼15 nm) coated with gold shells, between which a highly narrow and uniform nanogap (â¼1.1 nm) is formed owing to polyA anchored on the Au cores. The well controlled distribution of Raman reporter molecules, such as 4,4'-dipyridyl (44DP) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), are readily encoded in the nanogap and can generate strong, reproducible SERS signals. In addition, we have investigated the size-dependent SERS activity of GCNPs and found that with the same laser wavelength, the Raman enhancement discriminated between particle sizes. The maximum Raman enhancement was achieved at a certain threshold of particle size (â¼76 nm). High narrow nanogap-containing Au@Au core-shell SERS tags (GCTs) were prepared via the functionalization of hyaluronic acid (HA) on GCNPs, which recognized the CD44 receptor, a tumor-associated surface biomarker. And it was shown that GCTs have a good targeting ability to tumour cells and promising prospects for multiplex biomarker detection.
Subject(s)
Gold , Metal Nanoparticles/chemistry , Neoplasms/diagnostic imaging , Cell Line, Tumor , Dinitrobenzenes/chemistry , Dinitrobenzenes/pharmacology , Gold/chemistry , Gold/pharmacology , Humans , Hyaluronan Receptors/metabolism , Neoplasm Proteins/metabolism , Neoplasms/metabolism , Pyridines/chemistry , Pyridines/pharmacology , Spectrum Analysis, Raman/methodsABSTRACT
DNA origami technique was first introduced in 2006 by Rothemund, it has gained widespread research interest and led to explosive achievements, in which long single-stranded DNA (ssDNA) is folded into a designed nanostructure, in either two dimensions (2D) or three dimensions (3D), with the aid of many shorter staple strands. A series of methods for new design principles for DNA origami nanostructures have already been proposed, ranging from the preparation of scaffold to the folding mechanisms. After that, novel strategies in functionalizing DNA origami nanostructures and their practical applications are gradually becoming research hotspots. This review focuses on the development in the new scaffold design approaches, folding conditions, various nano objects functionalized on DNA origami nanostructures, and their applications as drug carriers in the recent five years. We anticipate more exploratory and extendible work developed based on the summary of progress obtained previously.
Subject(s)
DNA/chemistry , Drug Delivery Systems , Nanostructures/chemistry , Animals , HumansABSTRACT
A novel three-dimensional (3D) superstructure based on the growth and origami folding of DNA on gold nanoparticles (AuNPs) was developed. The 3D superstructure contains a nanoparticle core and dozens of two-dimensional DNA belts folded from long single-stranded DNAs grown inâ situ on the nanoparticle by rolling circle amplification (RCA). We designed two mechanisms to achieve the loading of molecules onto the 3D superstructures. In one mechanism, ligands bound to target molecules are merged into the growing DNA during the RCA process (merging mechanism). In the other mechanism, target molecules are intercalated into the double-stranded DNAs produced by origami folding (intercalating mechanism). We demonstrated that the as-fabricated 3D superstructures have a high molecule-loading capacity and that they enable the high-efficiency transport of signal reporters and drugs for cellular imaging and drug delivery, respectively.
Subject(s)
DNA/chemistry , Metal Nanoparticles/chemistry , Antibiotics, Antineoplastic/chemistry , Antibiotics, Antineoplastic/toxicity , Cell Line, Tumor , Cell Survival/drug effects , Cell-Penetrating Peptides/chemistry , Cell-Penetrating Peptides/metabolism , Doxorubicin/chemistry , Doxorubicin/toxicity , Drug Carriers , Gold/chemistry , Humans , Microscopy, Confocal , Nucleic Acid Amplification Techniques , Quantum Dots/chemistryABSTRACT
Prostate-specific antigen (PSA) is one of the most important biomarkers for the early diagnosis and prognosis of prostate cancer. Although many efforts have been made to achieve significant progress for the detection of PSA, challenges including relative low sensitivity, complicated operation, sophisticated instruments, and high cost remain unsolved. Here, we have developed a strategy combining rolling circle amplification (RCA)-based DNA belts and magnetic bead-based enzyme-linked immunosorbent assay (ELISA) for the highly sensitive and specific detection of PSA. At first, a 96-base circular DNA template was designed and prepared for the following RCA. Single stranded DNA (ssDNA) products from RCA were used as scaffold strand for DNA origami, which was hybridized with three staple strands of DNA. The resulting DNA belts were conjugated with multiple enzymes for signal amplification and then employed to magnetic bead based ELISA for PSA detection. Through our strategy, as low as 50 aM of PSA can be detected with excellent specificity.
