We have developed a novel method to protect DNA from cleavage using bioconjugated nanoparticles. Positively charged amino-modified silica nanoparticles have been directly prepared using water-in-oil microemulsion. Plasmid DNA can be easily enriched onto the positively charged nanoparticle surface, and the DNA strands are well protected from enzymatic cleavage. When incubated with nuclease enzyme for enzymatic cleavage, free plasmid DNA strands are completely cleaved, while those on the nanoparticle surfaces are intact. Our results clearly demonstrate unique properties of nanomaterials when combined with biomolecules. Our simple bionanotechnology will be highly useful in DNA separation, manipulation, and detection, and possibly in genetic engineering and gene therapy, as plasmid DNA can be protected in cellular environments without any change in its property.

A new category of mechanized nanoparticles, consisting of a hollow mesoporous silica spherical framework controlled by a supramolecular system containing the alpha-cyclodextrin (alpha-CD) ring on a stalk that is tethered to the pore openings on the nanosphere, is synthesized and tested. Construction of the nanovalve relies on the hydrogen-bonding interaction between alpha-CD and the stalk. The stalk is bonded to the nanoparticle chemically and contains an anilino group that is located on the end of the linker molecule that is closest to the pore entrance. When the alpha-CD ring is complexed with the stalk at neutral pH, the bulky cyclic component is located near the pore openings, thereby blocking departure of cargo molecules that were loaded in the nanopores and hollow interior of the particle. Protonation of the nitrogen atoms at lower pH causes the binding affinity to decrease, releasing the alpha-CD and allowing the cargo molecules to escape. The properties of this newly designed pH-responsive nanovalve are compared to those of conventional mesoporous silica nanoparticles. The on-command pH-activated release is measured using luminescence spectroscopy. The effect of different stalk lengths and pH conditions on the release of fluorescent dye cargo molecules is measured.

Lithium–sulfur (Li–S) batteries are one of the most promising next‐generation energy storage systems due to their ultrahigh theoretical specific capacity. However, their practical applications are seriously hindered by some inevitable disadvantages such as the insulative nature of sulfur and Li2S, volume expansion of the cathode, the shuttle effect of polysulfides, and the growth of lithium dendrites on the anode. Of these, the polysulfide shuttle effect is one of the most critical issues causing the irreversible loss of active materials and rapid capacity degradation of batteries. Herein, modified separators with functional coatings inhibiting the migration of polysulfides are enumerated based on three effects toward polysulfides: the adsorption effect, separation effect, and catalytic effect. To solve the shuttle effect problem, researchers have replaced liquid electrolytes with solid‐state electrolytes. In this review, solid‐state electrolytes for lithium–sulfur batteries are grouped into three categories: inorganic solid electrolytes, solid polymer electrolytes, and composite solid electrolytes. Challenges and perspectives regarding the development of an optimized strategy to inhibit the polysulfide shuttle for enhancing cycle stability in lithium–sulfur batteries are also proposed.