Adsorption of fluorescein by protein crystals

Abstract

Adsorption characteristics of native and cross-linked lysozyme crystals were examined using fluorescein as model adsorbate. The adsorption isotherms exhibited Langmuir or linear behavior. The affinity constant (b1) and the adsorption capacity (Qsat) for fluorescein were found to depend on the type and concentration of co-solute present in the solution. The dynamics of adsorption isotherm transition from Langmuir to linear showed that affinity of lysozyme for solutes increases in the order 2-(cyclohexylamino)ethanesulphonic acid (CHES), 4-morpholinepropanesulphonic acid (MOPS), acetate, fluorescein. Furthermore, the crystal morphology, the degree of cross-linking of the crystals, and, in particular, solution pH were identified as factors determining fluorescein adsorption by the lysozyme crystals. These factors seem to affect crystal capacity for the solute more than affinity for the solute. Adsorption of fluorescein by cross-linked tetragonal lysozyme crystals was exponentially dependent on the lysozyme net charge calculated from the final solution pH. The 3-5-fold increase in the fluorescein adsorption as a result of cross-linking is presumably due to the increasing hydrophobicity of the lysozyme crystal.

Surface-Modified Chitosan: An Adsorption Study of a “Tweezer-Like” Biopolymer with Fluorescein

“…The monolayer adsorption capacity (Q m ) for FL is 61.8 mg·g −1 which is comparable to other reports for adsorbents used for FL uptake (cf. Table S1) [26,30]. This high adsorption capacity may be due to the greater surface area in accordance with surface modification of chitosan, according to the SEM results.…”

“…Although FL is not considered highly toxic [22] (LC 50 = 3800-5000 mg/L) relative to other synthetic dyes, the problem of intense water coloration that occurs with trace amounts of this dye is understood due to aesthetic considerations. It is noteworthy that comparatively few studies have investigated fluorescein removal from aqueous media using adsorption techniques [23][24][25][26][27][28][29][30][31].…”

Superior Catalytic Performance of Gold Nanoparticles Within Small Cross-Linked Lysozyme Crystals

“…Protein crystals, which present highly ordered three-dimensional structures with high porosities (0.5–0.8), large surface areas (800–2000 m 2 g –1 ), and interpenetrating nanoporous and mesoporous solvent channels of 0.5–10 nm diameter, were traditionally used for the determination of protein structures, until their inherent fragility and solubility were addressed by cross-linking technology. These cross-linked protein crystals then emerged as a novel class of nanoporous materials, with a broad range of applications in biocatalysis, , separation, and adsorption . In addition, cross-linked protein crystals have been widely used for the fabrication of bionanohybrid materials since Colvin et al reported that their nanoporous structures can be applied in the immobilization of NPs .…”

“…These cross-linked protein crystals then emerged as a novel class of nanoporous materials, 17 broad range of applications in biocatalysis, 18,19 separation, 20 and adsorption. 21 In addition, cross-linked protein crystals have been widely used for the fabrication of bionanohybrid materials since Colvin et al reported that their nanoporous structures can be applied in the immobilization of NPs. 22 For example, Mann et al adopted cross-linked lysozyme crystals (CLLCs) as a template in the synthesis of nanoplasmonic arrays, 23 while Lu et al employed native lysozyme crystals to study the mechanism of biomolecule-directed AuNP formation.…”

Quantification of Binary Diffusion in Protein Crystals

“…Rhodamine B diffusion in the orthorhombic lysozyme crystal from a binary mixture obtained at same time and the same position as for fluorescein inFigure 3. tals,22 resulting in relatively small values for K. The influence of sodium present in the solution on the adsorption of rhodamine B by lysozyme crystals is unknown.…”