Controlled-Access Hollow Mechanized Silica Nanocontainers

Abstract

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.

Targeted Intracellular Delivery of Antituberculosis Drugs to Mycobacterium tuberculosis-Infected Macrophages via Functionalized Mesoporous Silica Nanoparticles

“…These pores run parallel through the MSNP and form a hexagonal pattern. MSNP are attractive delivery vehicles for M. tuberculosis drugs because they can be manufactured with a variety of surface and internal functionalizations, allowing incorporation of a variety of different design features (27,28), especially those that allow controlled release of cargo under specific environmental conditions (10,13,15,35,50). The biocompatible solid MSNP framework provides intrinsic stability compared with existing liposome-, polymer-, and copolymer-based nanoparticle delivery platforms.…”

Symmetry and dynamics of molecular rotors in amphidynamic molecular crystals

“…By comparison, the development of artificial molecular machines over the last few decades has evolved from the design of molecules that emulate the structure and motion of macroscopic objects (2,3), to elegant examples of photo-(4) and electroactive rotary molecular motors (5), chemoactive linear motors (6) and actuators (7), among many others (8,9). Although there is much important knowledge to be gathered from the syntheses and dynamics of molecules in solution, lessons from biological systems and potential materials applications have led to subsequent efforts toward the design and characterization of artificial molecular rotors linked to surfaces (10)(11)(12) and in the bulk of crystalline solids (13,14).…”

Aerosol Processing of Graphene and Its Application to Oil Absorbent and Glucose Biosensor

“…The fabrication of hollow GR has been studied because of their promising properties, such as large specific surface area, low density, and high porosity [50][51][52][53][54][55][56][57][58][59][60][61][62][63] . Accordingly, various methods such as the sol-gel and hydrothermal methods have been developed to synthesize hollow particles of inorganic materials using templates and a series of many steps for treatment [64][65][66][67][68][69] .…”