The design of immobilized enzyme preparations is an important and relevant area of modern sciences and technologies. Immobilization of enzymes from animal sources (component I) on natural carriers ...(component II) increases the system stability by protecting the active site of the enzyme from deactivation; facilitates the separation and accelerates the recovery of the enzyme. This makes reuse possible and provides a significant reduction in operating costs. Hydrolytic enzymes (such as lipases) and polysaccharides (such as chitosan) are the most promising of such pairs of components. The main attention here is devoted to the discussion on lipase immobilization on polysaccharide (mainly - chitin and chitosan). Based on the analysis of the available literature, the most adequate method is the immobilization of lipase from porcine pancreas (LPP) on polysaccharide particles (such as chitin or chitosan) pre-treated with ultrasound (to increase the particle surface area) and glutaraldehyde (for particle activation) that shows reasonably high LPP activity and stability. In order to increase further the activity of the lipase, some authors proposed to incorporate a spacer in the form of 1,3-diaminopropane (or 1,3-diaminobutane) prior to activation of the surface of the chitosan particles. In particular cases, the use of chitin (instead of chitosan) may be an alternative solution for biotechnological applications.
Recently the idea of constructing “supramolecular enzyme systems” realized in the so-called “coimmobilized multienzymatic systems” strategy. The most fascinating example is the combined assay of a mixture of native LPP, glycerol kinase (from Cellulomonas) and glycerol-3-phosphate oxidase (from Aerococcus viridans) linked by glutaraldehyde to chitosan (as shell for inorganic nanoparticle core). This material was placed on a Pt-electrode as biosensor and was successfully applied for amperometric determination of the triglyceride level in the serum of healthy and diseased person. Thus, the whole innovative research-production sequence is described by Aggarwal V. and Pundir C.S.: from simple components to advanced material and further biomedical application.
Thus, the following approach of lipase immobilization appears the most promising for future applications: a few types of lipases or the combination of LPP with some other enzymes immobilized simultaneously on multifunctional carriers (as nanohybrids of inorganic core and polysaccharide shell).
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•Immobilization of enzymes on natural carriers is an important area of biocolloids.•Lipase immobilized on chitosan particles (ChiPs) is useful for bionanotechnology.•Lipase adsorption on ChiPs (using ultrasound) increases the activity and stability.•Lipase linked to ChiPs (by glutaraldehyde) is useful for particle activation.
The design of polymeric composite materials (PCM) for the optical control of chemical substances is currently one of the actively developing fields of science “at the junction” of polymer, organic, ...and analytical chemistry. The purpose of this work is the preparation of PCM containing derivatives of crown ethers for the optical determination of barium ions. The polymeric composite materials containing a novel optical molecular sensor have been obtained and investigated on the basis of a number of film-forming polymers. The best results have been obtained for PCM based on polyvinyl butyral films (since the fluorescence and absorption maxima shifted by 9 and 16 nm, respectively) in the fluorescence and absorption spectra of this PCM in the presence of barium ions. This makes the proposed PCM highly promising as sensor elements for the detection of the barium ions in the aqueous solutions.
This review discusses recent works on monolayer, multilayer and polymer films of various crown-ether derivatives. Preparation and investigation of such membrane nanostructures based on photosensitive ...and surface-active crown-ethers is a rapidly growing field at the “junction” of colloids and polymers, materials sciences and nanotechnology. These membranes can serve as convenient models for studying the self-organization and molecular recognition processes at interfaces that are typical for biomembranes. The results obtained for such structures by absorption and fluorescence spectroscopy, atomic force and Brewster-angle microscopy, surface pressure and surface potential isotherm measurements have been described. The possibility of developing multifunctional materials possessing advanced properties has been demonstrated.
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•Recent works on layers and films of various crown-ether derivatives are discussed in this review.•Membrane nanostructures can serve for studying the self-organization and molecular recognition processes.•Possibility of developing micro- and nanomaterials possessing advanced properties is demonstrated.
Lipases play an important role in numerous metabolic reactions in all living species and may be activated at interfaces by some biopolymers in vivo, but inhibited—in vitro. The effect of two chitosan ...samples with different molecular weights on the activity of lipase from porcine pancreas (LPP) in triacetin hydrolysis was investigated. An equimolar amount or excess of chitosan activates LPP by a factor of 1.2 to 1.6. In order to support these data, a negatively charged polyelectrolyte—sodium polystyrene sulfonate (PSS)—was used instead of chitosan. A small increase in LPP activity was found also at an equimolar amount or excess of PSS. This unexpected effect can be explained as “interfacial activation” of LPP with opening of the hydrophobic channel for triacylglycerol hydrolysis. The observed activation effect is important for fundamental biochemistry of human and animal digestion models, as well as for further lipase applications.
Graphical abstract
Possible molecular interactions between chitosan and lipase from porcine pancreas
Photo-activated or “Caged” rhodamine dyes are the most useful for microscopic investigation of biological tissue by various fluorescent techniques. Novel precursor of the fluorescent dye (PFD813) has ...been studied for photosensitive staining of numerous animal cells. The functional rhodamine dye (Rho813) with intensive fluorescence has been obtained after photoactivation of its precursor PFD813 inside cells. The dye Rho813 has been successfully used for the optical detection of particular features in biological objects (HaCaT cells, HBL-100, MDCK, lymphocytes). Moreover, the chitosan conjugate with PFD molecules (“Chitosan-PFD813″) has been obtained and studied for the first time. The developed procedures and obtained data are important for further applications of novel precursors of fluorescent dyes (“caged” dyes) for microscopic probing of biological objects. As example, the synthesized “Chitosan-PFD813″ has been successfully applied in this study for intracellular transport visualization by fluorescent microscopy.
Photoactivated (“caged”) fluorescent dyes are modern tools for structure and function studies of cell membranes and subcellular organelles. Recently synthesized precursors of rhodamine fluorescent ...dyes (abbreviations PFD813 and PFD814) important for microscopic probing of biological objects have been studied in solution. In order to characterize the behavior at interfaces, monolayers of PFD813 and PFD814 on water have been formed and investigated. The interactions of these precursors with the biomembrane component dimyristoylphosphatidylethanolamine in monolayers at the air–water interface and after transfer to glass plates have been studied by measuring monolayer parameters and spectroscopic properties before and after photo-chemical formation of the fluorescent rhodamine dyes Rho813 and Rho814, respectively.
This paper discusses several works on supramolecular systems such as monolayer and multilayer, polymer films of various crown-containing dyes, surface-active monomers and polymers. Design, production ...and investigation of the membrane nanostructures based on crown ethers is a rapidly developing field at the "junction" of materials sciences and nanotechnology. These nanostructures can serve as convenient models for studying the self-organization and molecular recognition processes at interfaces that are typical for biomembranes. Based on the results obtained for such structures by absorption and fluorescence spectroscopy, atomic force and Brewster-angle microscopy, surface pressure and surface potential isotherm measurements, the possibility of developing micro- and nanomaterials possessing a set of specified properties (including chemosensor, photochromic and photorefractive materials) is demonstrated.
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The interaction of a photosensitive and surface-active dithiacrown-ether derivative (in polymer-based mixed monolayers) with Cd2+ from aqueous solutions, which has been found by ...surface pressure, potential and spectral changes, is promising for future applications in nanosized sensing materials.
The spectral and isotherm changes observed for a new photosensitive bis(crown ether) derivative assigned as optical molecular tweezers (OMT) in mixed monolayers with stearic acid by addition of ...ammonium and diammonium salts indicated the strongest complex formation between OMT and 1,3-diaminopropane dihydrochloride that may be of particular interest for design of chemosensoring nanomaterials.
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