Evaluating Immobilization of Hemoglobin onto Nanomesoporous MCM-41

Abstract

Introduction: The development and applications of biological products have been seriously hindered by conventional immobilization for its low efficiency and high cost. The immobilization on solid supports for enzyme is an area of intense research due to their widespread use in synthetic chemistry and various industries. This paper highlights a great interest in the adsorption of an enzyme on the solid porous structured material and the design of new controlled delivery systems. The enzyme immobilized on solid supports and synthetic materials of the reaction mixture with strong mechanical force and easy separation serves as a high selective catalyst. Objective: A novel protein delivery system for hemoglobin (Hb) enzyme was proposed by incorporating the molecular molecules into the mesopores of well-ordered hexagonal nanometer MCM (Mobil Composition of Matters) - 41. The prepared adsorbents were successfully applied to the design and synthesis of new functionalization materials. Various parameters affecting adsorption process, such as adsorption time, adsorption isotherm, and the reusability of adsorbent, were investigated. Methods: The interaction between Hb and MCM-41 was investigated using powder X-ray diffraction (XRD), Fourier infrared spectroscopy, UV-visible solid diffuse reflectance spectroscopy and 77 K lowtemperature N2 adsorption-desorption study. Results: The experimental parameters were optimized, including the concentrations of Hb, the MCM-41 amount, and the interior surface of phenyl-functionalized Ph-MCM-41 materials. Under the optimized conditions, the biocatalytic performance was studied for Hb/MCM-41 and Hb/Ph-(MCM-41). The adsorption process of Hb by MCM-41 / Ph-(MCM-41) was in agreement with the quasi-two-order kinetic model. Process of Hb adsorption by MCM-41 / Ph-(MCM-41) belongs to an exothermic reaction, the reaction is not reversible at 4°C and it is a spontaneous reaction. The Freundlich model can better describe the adsorption of hemoglobin on MCM-41 / Ph-(MCM-41). During the desorption process of composite (MCM-41)-Hb/[Ph-(MCM-41)]-Hb in 0.1 mol/L NaOH solution, the desorption rate can reach above 70% at 2 min. At 60 min, the desorption reached equilibrium and the desorption rates were 99.58% and 91.36%, respectively. The reuse activity experimental results indicated that the immobilized enzyme exhibited high catalytic activity. Reusability stability studies suggested that the prepared composites retained their activity even after five recycling runs. This shows that the phenylation of MCM-41 reduced the "leakage" of enzyme in the main material. Conclusion: The results of the present study demonstrated that Hb/MCM-41 and Hb/Ph-(MCM-41) are highly efficient potential nanobiocatalysts for the immobilization of enzymes onto mesoporous materials.