The effect of PEG length on the size and guest uptake of PEG-capped MIL-88A particles

Abstract

Different PEG length capping ligands were used to fabricated micro- and nano-MIL-88A particles. A model drug was encapsulated and released by counter-ion exchange, and its rate was dependent on the presence of PEG chains on the surface.

GraftFast Surface Engineering to Improve MOF Nanoparticles Furtiveness

“…In contrast, MIL‐100(Fe)@PEG 5KDa remained stable up to 24 h (194 nm), whereas MIL‐100(Fe)@PEG 2KDa already shown tendency to aggregate (600 nm). One can conclude that in this particular media, the stabilization effect increases with the PEG chain length, i.e., larger polymer chains covering the NPs provide additional colloidal stability . In the case of PBS, a similar stabilizing effect was observed, with only minor variations of the hydrodynamic diameter up to 6 h, from their original size 166 and 174 nm to less than 300 nm, for MIL‐100(Fe)@PEG 2KDa and PEG 5KDa , respectively.…”

“…One can conclude that in this particular media, the stabilization effect increases with the PEG chain length, i.e., larger polymer chains covering the NPs provide additional colloidal stability. [46] In the case of PBS, a similar stabilizing effect was observed, with only minor variations of the hydrodynamic diameter up to 6 h, from their original size 166 and 174 nm to less than 300 nm, for MIL-100(Fe)@PEG 2KDa and PEG 5KDa , respectively. This contrasts with the dramatic aggregation of the uncoated MIL-100(Fe) PBS suspensions at 6 h, likely due to chemical degradation as a consequence of the exchange of the organic linker with phosphates from the medium.…”

DNA Detection by Flow Cytometry using PNA‐Modified Metal–Organic Framework Particles

“…[2b, 13, 15] Given the similar molecular weight of undecynoic acid comparedt ot he fluorine-containing capping ligand described before, [13] we presume the BET areas to be similar.T he zeta potentialv alues of uncoated MIL-88A( 19.4 AE 3.4mV) were shifted to more neutral values of 12.4 AE 0.3 and 12.4 AE 0.4 mV in the case of alkyne- MIL-88Aa nd biotin-MIL-88A, respectively,i nl ine with ap artial capping of free Fe coordination sites at the surface, as discussed before. [15] In summary,w es uccessfully functionalized the surfaceo fM IL-88A with alkyne and biotin groups,w hich can be used for further covalent and non-covalentf unctionalization, respectively.…”

“…The changes observed in the spectra of the functionalized MOFs compared to the native MIL-88A are attributed to the flexibility of the framework and the effect of water absorption into the pores. [13][14][15] The presence of the ligands may further affect the degree of hydration.F igure 1 shows scanning electron microscopy (SEM) images andt he average length and width of MIL-88A, alkyne-MIL-88A, and biotin-MIL-88A particles, which confirmthe successful synthesis of the MOFs. As observed before, [13,15] adding small-MWligands to the MOF surface has only limited effect on the MOF particle size.…”

“…[13][14][15] The presence of the ligands may further affect the degree of hydration.F igure 1 shows scanning electron microscopy (SEM) images andt he average length and width of MIL-88A, alkyne-MIL-88A, and biotin-MIL-88A particles, which confirmthe successful synthesis of the MOFs. As observed before, [13,15] adding small-MWligands to the MOF surface has only limited effect on the MOF particle size. Here, we only observe as ignificant decreasei nt he width but not the length of the particles.…”