19F NMR ON/OFF nanoparticles: a universal approach for the specific detection of DNA-binding cancer biomarkers.

A supramolecular approach for the design of assembly-disassembly-driven 19F ON/OFF nanoparticles, triggered by specific molecular recognition, for the detection of DNA binding cancer biomarkers is reported. The key to our design strategy is the characteristic 19F NMR signal of the probe, which completely vanishes in the aggregated state due to the shortening of T2 relaxation. However, molecular recognition of DNA by the cancer biomarkers through specific molecular recognition results in the disassembly of the nanoparticles, which causes the restoration of the characteristic 19F signal of the probe. The universal nature of the approach is demonstrated through the selective detection of various cancer biomarkers including miRNA, ATP, thrombin, and telomerase.

Galactose Grafted Two-Dimensional Nanosheets as a Scaffold for the In Situ Synthesis of Silver Nanoparticles: A Potential Catalyst for the Reduction of Nitroaromatics.

Two major hurdles in NP-based catalysis are the aggregation of the NPs and their recycling. Immobilization of NPs onto a 2D support is the most promising strategy to overcome these difficulties. Herein, amphiphilicity-driven self-assembly of galactose-hexaphenylbenzene-based amphiphiles into galactose-decorated 2D nanosheet is reported. The extremely dense decoration of reducing sugar on the surface of the sheets is used for the in situ synthesis and immobilization of ultrafine catalytically active AgNPs by using Tollens' reaction. The potential of the system as a catalyst for the reduction of various nitroaromatics is demonstrated. Enhanced catalytic activity is observed for the immobilized AgNPs when compared to the corresponding discrete AgNPs. Recovery of the catalytic system from the reaction mixture by ultrafiltration and its subsequent recycling for several cycles without dropping its activity is shown. This is the first report demonstrating the in situ synthesis and immobilization of ultrafine AgNPs onto a 2D nanosheet that exhibits excellent catalytic performance for the reduction of nitroaromatics.

Efficient Capturing of Polycyclic Aromatic Micropollutants From Water Using Physically Crosslinked DNA Nanoparticles.

Design and synthesis of physically (non-covalently) cross-linked nanoparticles through host-guest interaction between ß-CD and adamantane is reported. Specific molecular recognition between ß-CD functionalized branched DNA nanostructures (host) and a star-shaped adamantyl-terminated 8-arm poly(ethylene glycol) polymer (guest) is explored for the design of the nanoparticles. The most remarkable structural features of DNA nanoparticles include their excellent biocompatibility and the possibility of various non-covalent interactions with both hydrophobic and hydrophilic organic molecules. Potential of DNA nanoparticles for the rapid and efficient capture of various micropollutants typically present in water including carcinogens (hydrophobic micropollutants), organic dyes (hydrophilic), and pharmaceutical molecules (hydrophilic) is also demonstrated. The capture of micropollutants by DNA nanoparticles is attributed to the various non-covalent interactions between DNA nanoparticles and the micropollutants. Our results clearly suggest that DNA based nanomaterials would be an ideal candidate for the capturing and removal of both hydrophilic and hydrophobic micropollutants typically present in water.

Galactose-Grafted 2D Nanosheets from the Self-Assembly of Amphiphilic Janus Dendrimers for the Capture and Agglutination of Escherichia coli.

High aspect ratio, sugar-decorated 2D nanosheets are ideal candidates for the capture and agglutination of bacteria. Herein, the design and synthesis of two carbohydrate-based Janus amphiphiles that spontaneously self-assemble into high aspect ratio 2D sheets are reported. The unique structural features of the sheets include the extremely high aspect ratio and dense display of galactose on the surface. These structural characteristics allow the sheet to act as a supramolecular 2D platform for the capture and agglutination of E. coli through specific multivalent noncovalent interactions, which significantly reduces the mobility of the bacteria and leads to the inhibition of their proliferation. Our results suggest that the design strategy demonstrated here can be applied as a general approach for the crafting of biomolecule-decorated 2D nanosheets, which can perform as 2D platforms for their interaction with specific targets.

Self-Assembly of an Aptamer-Decorated, DNA-Protein Hybrid Nanogel: A Biocompatible Nanocarrier for Targeted Cancer Therapy.

Nanocarrier-based chemotherapy is one of the most efficient approaches for the treatment of cancer, and hence, the design of new nanocarriers is very important. Herein, the design of a new class of physically cross-linked nanoparticles (nanogel) solely made of biomolecules including DNA, protein, and biotin as a nanocarrier for the targeted cancer therapy is reported. A specific molecular recognition interaction between biotin and streptavidin is explored for the cross-linking of a DNA nanostructure for the crafting of a nanogel. The most unique structural features of nanogels include the following: (i) excellent biocompatibility, (ii) decoration of the nanogel surface with biotin and streptavidin randomly that allowed the integration of aptamer DNA onto the surface of the nanostructure through the biotin-streptavidin interaction, (iii) high doxorubicin encapsulation efficacy through the intercalation of doxorubicin inside the DNA duplex, and (iv) stimuli responsiveness. The selective uptake of a doxorubicin-loaded nanogel by aptamer-receptor-positive cell lines (CCRF-CEM and HeLa) and its delivery inside the target cells are demonstrated. The selective uptake of the nanogel by CCRF-CEM and HeLa cells is attributed to the specific interaction between the aptamer DNA decorated on the surface of the nanogel with the PTK7 receptor overexpressed on CCRF-CEM and HeLa cell lines. These results imply that the nanogel obtained from the self-assembly of biomolecules would be ideal for the crafting of nanocarriers for targeted cargo delivery applications.