Not always what closes best opens better: mesoporous nanoparticles capped with organic gates

Abstract

Four types of calcined MCM-41 silica nanoparticles, loaded with dyes and capped with different gating ensembles are prepared and characterized. N1 and N2 nanoparticles are loaded with rhodamine 6G and capped with bulky poly(ethylene glycol) derivatives bearing ester groups ( 1 and 2 ). N3-N4 nanoparticles are loaded with sulforhodamine B and capped with self-immolative derivatives bearing ester moieties. In the absence of esterase enzyme negligible cargo release from N1, N3 and N4 nanoparticles is observed whereas a remarkable release for N2 is obtained most likely due to the formation of an irregular coating on the outer surface of the nanoparticles. In contrast, a marked delivery is found in N1, N3 , and N4 in the presence of esterase enzyme. The delivery rate is related to the hydrophilic/hydrophobic character of the coating shell. The use of hydrophilic poly(ethylene glycol) derivatives as gating ensembles on N1 and N2 enables an easy access of esterase to the ester moieties with subsequent fast cargo release. On the other hand, the presence of a hydrophobic monolayer on N3 and N4 partially hinders esterase enzyme access to the ester groups and the rate of cargo release was decreased.

Chromogenic Chemodosimeter Based on Capped Silica Particles to Detect Spermine and Spermidine

“…This amount is within the range of functionalization values previously described by our group in a great variety of nanogates (0.5-3.5 mmol/g) [50]. However, the amount of Rhodamine 6G is significantly higher (2.7 wt%) than that previously charged in previous works (0.57-0.95 wt% range) [51]. These differences are probably due to both the size of the organic arms and the gate construction method (directly or sequentially).…”

Copper-Catalyzed Synthesis of 4-CF3-1,2,3-Triazoles: An Efficient and Facile Approach via Click Reaction

“…The following supporting information can be downloaded at: , Table S1: Optimization of the Reaction Conditions; Copies of 1 H NMR, 19 F NMR and 13 C NMR spectra [ 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ].…”

Smart microdevices for nutraceutical-controlled delivery

“…The siliceous composition of MSPs causes the presence of silanol groups along their surface, both internal and external. 96,97 The well-known chemistry of Si makes the surface easy to functionalize with organic molecules of several types. 98 This allows the formation of hybrid organic-inorganic compounds based on MSPs, whose joint-properties overcome those of the starting materials.…”

“…101 Due to the presence in the organism of a wide variety of biochemical phenomena able to be used as stimuli, the number of switchable moieties used to recognize them is vast and constantly growing. [96][97][98][102][103][104][105] All the supramolecular interactions stablished between the components, add to the new hybrid material some "extra" properties over those that MSPs generally had. Among these properties, those detailed below can be highlighted.…”

“…95 Homeostasis of the intestinal barrier is compromised by numerous diseases of the digestive system, such as inflammatory bowel diseases or some types of cancer. [96][97][98][99][100][101] Alterations in the intestinal barrier, whether profitable to induce treatment or damaging due to pathologies or drug side effects, end up affecting the entire organism. 101 Therefore, the study of the interaction of drug carriers with an intestinal barrier model, either in vitro or in vivo, is essential to validate its oral administration.…”