Size-Controllable Synthesis of Uniform Spherical Covalent Organic Frameworks at Room Temperature for Highly Efficient and Selective Enrichment of Hydrophobic Peptides

Abstract

Covalent organic frameworks (COFs) represent a new class of porous crystalline polymers with a diversity of applications. However, synthesis of uniform spherical COFs poses a great challenge. Here, we present size-controllable synthesis of uniform spherical COFs from nanometer to micrometer scale by a facile approach at room temperature. The as-prepared spherical COFs with different sizes exhibited ultrahigh surface area, good crystallinity, and chemical/thermal stability. Multifarious microscopic and spectroscopic techniques were performed to understand the formation mechanism and influencing factors of the spherical COFs. Moreover, the general applicability for room-temperature synthesis of the spherical COFs was demonstrated by varying different building blocks. Spherical COFs, because of the advantageous nature of their surface area, hydrophobicity, and mesoporous microenvironment, serve as an attractive restricted-access adsorption material for highly selective and efficient enrichment of hydrophobic peptides and size exclusion of macromolecular proteins simultaneously. On this basis, the spherical COFs were successfully applied to the specific capture of ultratrace C-peptide from human serum and urine samples. This research provides a new strategy for room-temperature controllable synthesis of uniform spherical COFs with different sizes and extends the application of COFs as an attractive sample-enrichment probe for clinical analysis.

The Application of Covalent Organic Frameworks for Chiral Chemistry

“…There is also a report about preparing sphere COFs with uniform size recently. [89] Another issue is that π−π stacked structures of COFs may trigger the thermal decay of photoexcited states easily and result in less or nonemissive, limiting the application of luminescent COFs. Some solutions have been proposed, such as exfoliating COFs into ultrathin nanosheets or postmodified skeletons by organic dye molecules with fluorescence.…”

Nanoscale covalent organic frameworks as theranostic platforms for oncotherapy: synthesis, functionalization, and applications

“…The particle size of the obtained TAPB-PDA COF varied from the minimum of 200 nm to the maximum of 500 nm with changes in the initial monomer concentration. This approach has been widely applied to the synthesis of various Schiff-base COFs, [220][221][222][223][224] implying its widespread feasibility.…”

Recent advances of sorption efficiency and mechanism of radionuclides on covalent organic frameworks materials

“…因此, 合成热 稳定、耐酸碱和抗辐照的COFs仍然存在不小挑战. 国 内外学者通过预先设计组分、控制合成条件和选择不 同方法可制备不同形貌的COFs, 如球状、薄片状 [58] 、 纳米纤维状 [33] 和花瓣状(图1(e~h)) [56] , 这些COFs的热 [45] ; 球状(e)、薄片状(f)、纳米纤维状(g)和花瓣状(h) COF的SEM形貌图 [56,58,67] (网络版彩图) MC法优化反应条件合成同样具有高稳定性的COFs是 一项艰巨的挑战. Biswal等 [61] 具有高效的选 择性吸附和强亲和力 [74] .…”

“…Tetragonal (a), rhombic (b), hexagonal star (c) and hexatomic ring (d) COF skeleton, respectively; (e-h) SEM images of COF with spherical (e), lamellar (f), nanofiber (g) and petaloid (h) morphology, respectively[56,58,67] (color online).…”