Monodispersed MOF-808 Nanocrystals Synthesized via a Scalable Room-Temperature Approach for Efficient Heterogeneous Peptide Bond Hydrolysis

Abstract

Zr(IV)-based metal-organic frameworks (MOFs) such as the Zr(IV) trimesate MOF-808 are promising materials for catalytic applications. In this work, we report an aqueous solution-based room temperature strategy to produce well-defined monodispersed MOF-808 nanocrystals down to 35 nm with a high space-time yield, up to 2516 g/ m 3 / day, and an excellent crystallinity and porosity. The resulting nanocrystals show remarkable colloidal dispersion during one day in a wide range of nanoparticles concentrations. As a result, 35 nm MOF-808 colloidal-level nanocrystals exhibit the highest rate of selective peptide bond and protein hydrolysis among reported Zr(IV)-based MOFs. This result may open new opportunities for highly efficient peptide or protein hydrolysis using scalable nano-catalyst.

Enhancing the Catalytic Activity of MOF‐808 Towards Peptide Bond Hydrolysis through Synthetic Modulations

“…[14,25] Recently, we have also showcased that the linker : metal ratio in the synthesis can be reliably used to tune the size of MOF-808 particles, and that such control over the synthesis can ultimately be used to boost the MOF-808 reactivity. [35] In this work, MOF batches with smaller particles hydrolysed peptide bonds significantly faster than large ones. However, the most hydrolytically active MOF-808 in this work was still an order of magnitude slower than our original report using MOF-808 synthesized with formic acid and DMF at 130 °C, even though our novel synthesis provided particles much smaller than the first time, suggesting the synthetic protocol plays an important role in the final reactivity of the MOF.…”

“…Particle size and number of defects, often related to enhanced reactivity in the literature, do not explain the differences observed in reactivity studies here. MOFs with smaller particle sizes are often regarded as more active MOFs [35,52,53] due to the increase in external surface areas. However, the similar particle sizes of MOF 130-20-A/B/D/E clearly did not govern the observed reactivity.…”

“…Considering the striking effects of the Zr(IV) precursor used in the synthesis on the reactivity of MOF-808, we further evaluated how this precursor influence would be affected by altering the reaction time and temperature used during synthesis, given that MOFs with different crystallinity, [40] particle sizes, [35] and number of defects [23,36] have been previously obtained by varying these parameters. As MOF-808 was originally synthesized at 100 °C for a longer time, [54] we have expanded our matrix of temperature and time to effect the proposed comparison (Figure 4).…”

“…For example, when UiO‐66 was prepared using trifluoracetic acid as a modulator, it led to a more defective structure, and a 10‐fold increase in the peptide bond hydrolysis rate was observed [14,25] . Recently, we have also showcased that the linker : metal ratio in the synthesis can be reliably used to tune the size of MOF‐808 particles, and that such control over the synthesis can ultimately be used to boost the MOF‐808 reactivity [35] . In this work, MOF batches with smaller particles hydrolysed peptide bonds significantly faster than large ones.…”

Impact of capping agent removal from Au NPs@MOF core–shell nanoparticle heterogeneous catalysts

“…1) takes advantage of our previously reported two-steps room temperature synthesis of MOF-808 with small modifications. 14 PVP is a commonly used stabilizer in the preparation of MNPs for its role not only in the control of their size/shape but also in the prevention of their aggregation. Au was used as a model metal to investigate the removal of surface PVP due to its high reactivity for some standard catalytic reactions once the active sites are accessible.…”