Protein Crystals as Novel Microporous Materials

Abstract

Cross-linked protein crystals (CLPCs) constitute a novel type of molecular sieves with high porosity. In order to characterize the fully hydrated CLPC, the method of macromolecular porosimetry was applied. This technique allows one to estimate the apparent pore sizes and pore size distribution in solid and soft hydrated porous sorbents directly from size exclusion chromatography. According to this method, CLPCs offer a wide range of pore size (15−100 Å), porosity (0.5−0.8), and pore surface area (800−2000 m2/g). These CLPC materials can be made chemically and mechanically stable, and are capable of separating molecules by size, chemical structure, and chirality.

Cross-linked protein crystals for vaccine delivery

“…The solvent content of typical protein crystals is composed of uniform solvent-filled channels that ranges from 30% to 65% of the total crystal volume (30). For example, the porosity of CLPC-HSA was determined to be 65% (17). The appearance of a macroscopic protein crystal containing roughly 10 7 -10 15 molecules begins with formation of small but stable nuclei (30-40 molecules) whose intermolecular contacts are similar to those found in the final crystal.…”

“…(ii) Protein crystals by definition are very pure, can currently be produced on large scale (13), and do not require cumbersome manufacturing processes used for the preparation of synthetic microspheres. (iii) CLPCs are remarkably stable (13) at elevated temperature, in organic and mixed solvents, and against mechanical disruption and shear (14)(15)(16)(17). (iv) Because the degree of cross-linking can be manipulated by the concentration of the cross-linking agent, time of reaction, and the reaction conditions, one can produce a variety of CLPCs with different dissolution profiles.…”

“…(iv) Because the degree of cross-linking can be manipulated by the concentration of the cross-linking agent, time of reaction, and the reaction conditions, one can produce a variety of CLPCs with different dissolution profiles. In short, CLPCs constitute a type of biodegradable microparticulates with high-porosity, pore surface area, and a wide range of pore size (17).…”

Microindentation Hardness of Protein Crystals under Controlled Relative Humidity

“…This also leads to the difficulty of protein crystallization [8]. On the other hand, it is expected that these features can lead to unique mechanical properties [9][10][11]. The intracrystalline water in protein crystals is qualitatively classified into two types: one is free water moving freely through the crystals and the other is bound water held around each protein molecule [12][13][14].…”

Template‐Directed Synthesis of Nanoplasmonic Arrays by Intracrystalline Metalization of Cross‐Linked Lysozyme Crystals

“…[1] These channels provide a chemically heterogeneous and chiral environment that comprises 30-65 % of the total crystal volume with associated pore volumes and surface areas in the range of 0.9-3.6 mL g À1 and 800-3000 m 2 g À1 , respectively. [1][2][3] The use of protein crystals for materials applications has been traditionally restricted by their mechanical and chemical fragility; however the onset of simple cross-linking technology has significantly extended the scope for protein aggregates and crystals in catalysis and drug delivery, [4,5] separation science, [2,[6][7][8] and sensors. [9] In general, cross-linking is achieved by soaking the protein crystals in a 1-5 % aqueous glutaraldehyde solution containing a heterogeneous mixture of monomers and aldol-based oligomers of various lengths.…”