6 research outputs found
Porous MetalâOrganic Framework Nanoparticles
Metalâorganic frameworks (MOFs) are hybrid crystalline particles composed of metal cations and organic linkers. Ranging from micro- to nanoscale depending on the preparation conditions, they have achieved a prevalent position among porous materials. The fact that varying either the metal cation or the organic component leads to a wide range of pore sizes and structures has made them very appealing materials in a broad variety of fields, including gas storage, heterogeneus catalysis, separation, imaging, biosensing, agriculture, and biomedicine.
By optimizing the internal pore volume, many molecules of different natures can be accommodated within the matrix. For instance, the anticancer drug doxorubicin is well known to enter within iron trimesate MIL-100(Fe) nanoMOF. However, the use of this inclusion complex in biomedicine requires the controlled release of the drug. As reported in one of the articles within this Special Issue [1], this goal can be achieved either by modifying the way the drug is loaded into the MOF or by noncovalently coating the surface with appropriate biocompatible materials. Furthermore, the latter can also lead to a higher colloidal stability of the particles. The innovative use of the ssNMR technique on these inclusion complexes associated with a selective isotope labeling strategy gave the authors deeper insights into both the structure of the complexes as well as to the drug release rates and mechanism
Design of engineered cyclodextrin derivatives for spontaneous coating of highly porous metal-organic framework nanoparticles in aqueous media
Nanosized metal-organic frameworks (nanoMOFs) MIL-100(Fe) are highly porous and biodegradable materials that have emerged as promising drug nanocarriers. A challenging issue concerns their surface functionalization in order to evade the immune system and to provide molecular recognition ability, so that they can be used for specific targeting. A convenient method for their coating with tetraethylene glycol, polyethylene glycol, and mannose residues is reported herein. The method consists of the organic solvent-free self-assembly on the nanoMOFs of building blocks based on beta-cyclodextrin facially derivatized with the referred functional moieties, and multiple phosphate groups to anchor to the nanoparticlesâ surface. The coating of nanoMOFs with cyclodextrin phosphate without further functional groups led to a significant decrease of macrophage uptake, slightly improved by polyethylene glycol or mannose-containing cyclodextrin phosphate coating. More notably, nanoMOFs modified with tetraethylene glycol-containing cyclodextrin phosphate displayed the most effcient âstealthâ effect. Mannose-coated nanoMOFs displayed a remarkably
enhanced binding affnity towards a specific mannose receptor, such as Concanavalin A, due to the multivalent display of the monosaccharide, as well as reduced macrophage internalization. Coating with tetraethylente glycol of nanoMOFs after loading with doxorubicin is also described. Therefore, phosphorylated cyclodextrins o er a versatile platform to coat nanoMOFs in an organic solvent-free, one step manner, providing them with new biorecognition and/or âstealthâ properties
Poly(amido amine)-Based Mannose-Glycodendrimers As Multielectron Redox Probes for Improving Lectin Sensing
An easy-to-prepare series of electroactive polyÂ(amido
amine) (PAMAM)-based
dendrimers of generations G0 to G2 having mannopyranosylferrocenyl
moieties in the periphery to detect carbohydrateâprotein interactions
is reported. The synthesis involved the functionalization of the PAMAM
surface with azidomethylferrocenyl groups and subsequent coupling
of mannoside units by the CuÂ(I)-catalyzed Huisgen reaction. The binding
affinity of the series of electroactive glycodendrimers was studied
by isothermal titration calorimetry (ITC) and differential pulse voltammetry
(DPV). Upon complexation of the glycodendrimers conjugates with prototypical
concanavalin A (Con A), voltammograms showed a decrease of the peak
current. Such dendrimers showed a notable improvement of redox sensing
abilities toward Con A when compared with mono- and divalent analogues,
based on both the glycoside multivalent and ferrocene dendritic effects
βâCyclodextrin-Bearing Gold Glyconanoparticles for the Development of Site Specific Drug Delivery Systems
Three novel gold nanoparticles containing
multiple long, flexible
linkers decorated with lactose, β-cyclodextrin, and both simultaneously
have been prepared. The interaction of such nanoparticles with β-d-galactose-recognizing lectins peanut agglutinin (PNA) and
human galectin-3 (Gal-3) was demonstrated by UVâvis studies.
Gal-3 is well-known to be overexpressed in several human tumors and
can act as a biorecognizable target. This technique also allowed us
to estimate their loading capability toward the anticancer drug methotrexate
(MTX). Both results make these glyconanoparticles potential site-specific
delivery systems for anticancer drugs