Biomimetic properties

Due to their better biomimetic properties, phospholipids have been proposed as an alternative to 1-octanol for lipophiiicity studies. The use of immobilized artificial membranes (lAM) in lipophiiicity determination was recently reviewed and we thus only briefly summarize the main conclusions [108]. lAM phases are silica-based columns with phospholipids bounded covalently. lAM are based on phosphatidylcholine (PC) linked to a silica propylamine surface. Most lipophiiicity studies with lAM were carried out using an aqueous mobile phase with pH values from 7.0 to 7.4 (log D measurements). Therefore, tested compounds were neutral, totally or partially ionized in these conditions. It was shown that the lipophiiicity parameters obtained on I AM stationary phases and the partition coefficients in 1-octanol/water system were governed by different balance of intermolecular interactions [109]. Therefore the relationships between log kiAM and log Poet varied with the class of compounds studied [110]. However, it was shown that, for neutral compounds with log Poet > 1, a correspondence existed between the two parameters when double-chain lAM phases (i.e., lAM.PC.MG and IAM.PC.DD2) were used [111]. In contrast, in the case of ionized compounds, retention on lAM columns and partitioning in 1 -octanol / water system were significantly different due to ionic interactions expressed in lAM retention but not in 1-octanol/water system and due to acidic and basic compounds behaving differently in these two systems. 

Techniques to produce multiscale biomaterial scaffolds with designer geometries are the need of the hour to provide improved biomimetic properties for functional tissue replacements. While micrometer fibers generate an open pore stnicture, nanofibers support cell adhesion and facilitate cell-cell interactions. This was further proven by cell penetration studies, which showed superior ingrowth of cells into hierarchical structures. Mixed bimodal scaffolds of two different polymers are another promising approach, because they exhibit hierarchical pore/ surface systems and combine the beneficial properties of both polymers at two different scales. Vaiious 3D micro- and nanoscale multiscale scaffolds have been fabricated through various techniques and were found to have the potential to essentially recreate natural bone, cardiac, neural, and vascular tissues. 

A series of Cu and Cu compounds with tridentate ligands incorporating benzimidazole or pyrazole have also been synthesized and structurally characterized. " Their nitrite binding and biomimetic properties were investigated and the Cu complexes were shown to bind nitrite with high affinity either through one or both O atoms depending on the stereochemical feature... 

Huang Z, Feng Q, Yu B, Li S (2011) Biomimetic properties of an injectable chitosan/nano-hydroxyapatite/collagen composite. Mater Sd Eng C 31 683-687... 

The recent trend of tissue engineering is the design of biomimetic scaffolds with similar mechanical, stmcmral and chemical properties compared to the natural extracellular matrix (ECM) of the tissue to be regenerated. In the case of PURs, biomimetic properties can be obtained by tuning the PUR block structure and composition, as underlined in the following paragraphs. 

This chapter discussed synthesis of PURs with biomimetic properties and tailored biodegradation as well as the most used processing or bulk/surface modification methods for the preparation of biomimetic scaffolds. 

CiardeUi G, Sartori S, SUvestri A, Serafini P, Caporale A, Boccafoschi F. Multiblock polyurethanes in biomedical applications fine tuning of degradation and biomimetic properties. AIP CortfProc 2010 1255 16-8. 

Clusters of metals are also cores for the assembly of dendrimers which show electrochemical and biomimetic properties [63, 64], A peculiar case is represented by the stabilization of gold nanoparticles with sulfur containing dendritic ligands which provide the control of nano-architecmre dimensions for stable assemblies [65]. 

Polymers represent the largest and versatile class of biomaterials being extensively applied in multitude of biomedical applications. This versatility is attributed to the relative ease with which polymers can be designed and prepared with a wide variety of structures and appropriate physical, chemical, surface and biomimetic properties. As described in this book a new arsenal of synthetic and applied methodologies are under study that provides an enhanced range of tools to greatly expand the biomedical applications of polymeric materials. 

The future requirement for the polymers would be biomimetic properties contain chemical signals, soluble growth factors, physical properties, mechanical properties which are similar to natural ECM and more conductive for epidermis and dermis regeneration. 

Ohnishi, M., Ishimoto, C., and Seto, J., The biomimetic properties of gas-sensitive films for odorants constructed by the Langmuir-Blodgett techniques, Solid Films, 210/211, 455, 1992. Okahata, Y., Ye, X., Shimizu, A., and Ebato, H., Interactions of bioactive compounds with lipid membranes deposited on a quartz crystal microbalance. Thin Solid Films, 180, 51, 1989. 

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