| 1. |
- Shen, Xiantao, et al.
(författare)
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Catalytic Formation of Disulfide Bonds in Peptides by Molecularly Imprinted Microgels at Oil/Water Interfaces
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 8:44, s. 30484-30491
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Tidskriftsartikel (refereegranskat)abstract
- This work describes the preparation and investigation of molecularly imprinted polymer (MIP) microgels (MGs) stabilized Pickering emulsions (PE) for their ability to catalyze the formation of disulfide bonds in peptides at the O/W interface. The MIP MGs were synthesized via precipitation polymerization and a programmed initiator change strategy. The MIP MGs were characterized using DLS analysis, SEM measurement and optical microscopy analysis. The dry and wet MIP MGs showed a hydrodynamic diameter of 100 nm and 280 nm, respectively. Template rebinding experiment showed that the MIP MGs bound over two times more template (24 mg g-1) compared to the uptake displayed by a non-imprinted reference polymer (NIP) MG (10 mg g-1) at saturation. Using the MIP MGs as stabilizers, catalytic oxidation systems were prepared by emulsifying the oil phase and water phase in presence of different oxidizing agents. During the cyclization, the isolation of the thiol precursors and the oxidizing reagents non-selectively decreased the formation of the byproducts, while the imprinted cavities on the MIP MGs selectively promoted the intramolecular cyclization of peptides. When I2 was used as the oxidizing agent, the MIP-PE-I2 system showed a product yield of 50 %, corresponding to a nearly two-fold increase compared to the non-imprinted polymer NIP-PE-I2 system (26 %). We believe the interfacial catalysis system presented in this work may offer significant benefits in synthetic peptide chemistry by raising productivity while suppressing the formation of by-products.
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| 2. |
- Shen, Xiantao, et al.
(författare)
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Reflux precipitation polymerization : A new synthetic insight in molecular imprinting at high temperature
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; :85, s. 81458-81461
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of uniform molecularly imprinted polymer (MIP) microspheres (MSs) using distillation precipitation polymerization (DPP) at high temperature has attracted great interest in the field of molecular imprinting. However, there are still some shortcomings in this method. In this work, to create uniform MIP MSs in a short time and to demonstrate the effects of high temperature on imprinting performance, a new precipitation polymerization method (reflux precipitation polymerization, RPP) was used for the first time to fabricate MIP MSs in this study. The SEM images of the polymeric MSs indicate the presence of template molecules could improve the particle morphology and size uniformity. The specific molecular recognition of the monodispersed MIP MSs was confirmed by fluorescence measurement and HPLC-UV analysis. The binding behavior of the MIP MSs was simulated using the heterogeneous Freundlich isotherm, which shows that the MIP MSs produced by the RPP possess compatible selectivity in comparison with those produced by traditional PP method. It is noted that, for the first time, we demonstrated that molecular imprinting at high temperature was only successful when electrostatic interactions played important roles in the imprinting process.
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