Novel core-shell-shell structured nanoparticles 75 nm in diameter with all-in-one "smart" functional capabilities for simultaneous photoresponsive drug release, photodynamic therapy, and cell imaging are designed and prepared. These nanoparticles consist of an upconversion (UC) emission core, a photosensitizer-embodied silica sandwich shell, and a β-cyclodextrin (β-CD) gated mesoporous silica outmost shell with drugs (Rhodamine B as a model) loaded inside. We show in this proof-of-concept demonstration that, under 980 nm near-infrared irradiation, UC 540 nm green light emissions were emitted for cell imaging, and 660 nm red light emissions were excited for activating photosensitizers to generate singlet oxygen, which could be exploited directly to kill cancer cells and simultaneously dissociate β-CD gatekeeper to release drugs. The preliminary results reported here will shed new light on the future design and applications of multifunctional platforms for cancer therapy and diagnostic.
Functionalized silica sols were obtained by the hydrolytic condensation of (γ-methacryloxypropyl)trimethoxysilane (MPMS), (γ-glycidyloxypropyl)trimethoxysilane (GPMS) and tetraethoxysilane (TEOS). Three different sols were obtained: MPS (derived from MPMS and TEOS), GPS-MPS (derived from GPMS, MPMS and TEOS), and GPSD (derived from GPMS, TEOS and diglycidyl ether of bisphenol A, DGEBA). These silica sols were mixed with a phenolic resin (PR). Ethylenediamine was used as a hardener for epoxy-functionalized sols and benzoyl peroxide was used as an initiator of the free-radical polymerization of methacrylate-functionalized silica sols. Glass fiber-reinforced composites were obtained from the neat PR and MPS-PR, GPS-MPS-PR and GPSD-PR. The resulting composites were evaluated as ablation resistant materials in an acetylene-oxygen flame. A large increase in the ablation resistance was observed when the PR was modified by the functionalized silica sols. The ablation resistance of the composites decreased as follows: GPSD-PR > MPS-PR > GPS-MPS-PR > PR.
The CO 2 /CH 4 competitive adsorption behaviors in bituminous coal before and after oxidation are investigated by the density functional theory. It is found that coal oxidation can decrease the adsorption energy of CO 2 and CH 4 on the functional groups. There exists a critical distance when CO 2 and CH 4 are adsorbed on the functional groups. The effects of different functional groups (−N−, −S−, −HS, −OH) of coal on adsorption characteristics are also evaluated. The interaction between CO 2 and the −N− functional group is strongest among these functional groups. The adsorption performance under different CO 2 /CH 4 ratios is examined. The displacement of CH 4 will be enhanced at a higher CO 2 /CH 4 molar ratio. Meanwhile, the grand canonical Monte Carlo simulation is carried out to analyze the effect of the coal density change caused by oxidation on CO 2 /CH 4 competitive adsorption. The evaluation of the coal oxidation effect on CO 2 /CH 4 competitive adsorption characteristics is helpful for an understanding of the gas adsorption mechanism in coal seams, which is beneficial to the development of CO 2 -enhanced coalbed methane recovery.
Abstract:In this study, we report UV-MALDI-TOF MS evidence of a fullerene-like silsesquioxane, a high-symmetry polyhedral oligomeric silsesquioxane (POSS or SSO) formulated as R 60 -Si 60 O 90 or T 60 (T = RSiO 1.5 ). The T 60 preparation can be performed using a normal hydrolytic condensation of [(3-methacryloxy)propyl]trimethoxysilane (MPMS) as an example. Theoretically, four 3sp 3 hybrid orbitals (each containing an unpaired electron) of a Si atom are generated before the bond formation. Then it bonds to another four atom electrons using the four generated hybrid orbitals which produced a stable configuration. This fullerene-like silsesquioxane should exhibit much more functionality, activity and selectivity and is easier to assemble than the double bonds in a fullerene.Keywords: polyhedral oligomeric silsesquioxane (POSS); high-symmetry; fullerene-like silsesquioxane; synthesis and characterization The fullerene buckyball (FBB), C 60 , was named "Molecule of the Year" for 1991 by Science [1]. Since the discovery of the C 60 buckyball, fullerene science has continued to accelerate, investigating both the basic science and its potential applications [2,3]. One investigation involves a major focus on its analogue, the Si 60 cluster [4,5]. For Si 60 clusters, the cages should not be very stable due to the use of three (3sp 3 ) orbitals to bond to other Si atoms. Thus, the cages need some other atoms for the fourth bond whereas the C 60 fullerene uses the second period sp 2 orbitals along with a π bond to bond exclusively with other C atoms. Most investigations focus on endohedral Si 60 isomers (using the fourth bond of the 3sp 3 orbital) which are unstable [6]. To produce a stable Si 60 configuration, Wang and Yang conducted ab initio calculations based on density functional theory on a Si 60 fullerene-like cage passivated with F or Cl atoms [7]; however, this research is limited by a complex experimental synthesis.In this study, we report UV-MALDI-TOF MS evidence of a fullerene-like silsesquioxane, a high-symmetry polyhedral oligomeric silsesquioxane (POSS or SSO) formulated as R 60 -Si 60 O 90 or T 60 (T = RSiO 1.5 ) [8]. Theoretically, four 3sp 3 hybrid orbitals (each containing an unpaired electron) of a Si atom are generated before the bond formation. Then it bonds to another four atom electrons using the four generated hybrid orbitals which produced a stable configuration. A significant difference between a FBB and T 60 POSS is that the cage in the former is the four-bond (three 2sp 2 hybrid orbits and one original 2p orbital) connection of each C atom on the FBB surface, while it is the three-bond (three of four 3sp 3 hybrid orbits) connection of each Si atom on the POSS surface. The remaining bond to each silicon connects to a pendant organic group adorning the surface of the T 60 cage, showing a hedgehog buckyball (HBB, see Figure 1). These organic groups exhibit much more functionality, activity and
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