**7. Zeolite scaffolds**

Zeolite scaffolds provide a framework above and within which cells seeded in the culture medium can adhere and over time populate them. These processes require that the scaffold structure must also be able to support a growing number of cells allowing the transport of sufficient amounts of nutrients and the removal of waste products having an extended surface where the cells can adhere and migrate freely so as to form a mass of cells with subsequent deposition of an active extracellular matrix (ECM) [21].

A scaffold is a critical component of tissue engineering, as it is intended to release, contain, and form new tissue in vitro or to promote tissue repair in vivo. Porosity, architecture, and rate of degradation are important aspects of the material that allow the growth of cells that guide the formation of tissues such as bone.

An ideal scaffold should have the following characteristics:


*Zeolites as Chameleon Biomaterials: Adsorption of Proteins, Enzymes, Foods, Drugs, Human… DOI: http://dx.doi.org/10.5772/intechopen.88422*

• High surface area to boost the cell adhesion

to assist the body's natural healing processes. The ability of a cell to recognize and interact with the substrate represents the first indispensable step, without which processes such as cell adhesion proliferation, migration, and differentiation would not be possible. Therefore the understanding of the mechanisms that determine the early phases of cell-material adhesion, as well as their control, is indispensable for the design of biomaterials. Both the mechanical and biochemical properties of the material determine the efficacy and agreed with which the cells recognize the material. The possibility of modifying and controlling surface properties at the micro-/ nanolevel constitutes one of the major breakthroughs, because it opens a whole new range of strategies seeking the desired interaction with the biological environment. In order to prepare a new generation of biomaterials with enhanced properties, a different approach needs to be reached, based on a more fundamental understanding of the way in which the structure of a biomaterial controls its biological activity. The chemical properties influence the surface properties of a material and, consequently, cell behavior. When cells are exposed to a suitable scaffold, a layer of proteins is adsorbed on the scaffold surface within a few milliseconds. Thus cells "see" the layer of adsorbed proteins rather than the actual abiotic surface. The chemistry of the surface of a scaffold can be developed in order to control the adsorption of proteins, which in turn controls cell adhesion. According to the hoped-for result, the chemical characteristics of the surface of a material can be modified to modulate the interactions of cells adherent to the substrate, with consequent influence on morphology, migration, differentiation, proliferation, and cell apoptosis. The effect on cell behavior starts at the point of interaction. Furthermore,

the conformation of the surface chemistry also affects the way proteins are

**7. Zeolite scaffolds**

*Zeolites - New Challenges*

cellular matrix (ECM) [21].

**46**

immobilized and the adsorption of these on the surface. Starting from this assumption, we designed and prepared various crystalline zeolite scaffolds, which are different depending on the preparation method. It is evident that a porous, crystalline material having an inorganic framework with modulable acidity, hydrophilicity, and pore size constitutes a stable, homogeneous, ion- and solvent-available support. Zeolite membranes symbolize this novel type of chameleonic scaffold.

Zeolite scaffolds provide a framework above and within which cells seeded in the culture medium can adhere and over time populate them. These processes require that the scaffold structure must also be able to support a growing number of cells allowing the transport of sufficient amounts of nutrients and the removal of waste products having an extended surface where the cells can adhere and migrate freely so as to form a mass of cells with subsequent deposition of an active extra-

A scaffold is a critical component of tissue engineering, as it is intended to release, contain, and form new tissue in vitro or to promote tissue repair in vivo. Porosity, architecture, and rate of degradation are important aspects of the material that allow the growth of cells that guide the formation of tissues such as bone.

An ideal scaffold should have the following characteristics:

and access to nutrients and metabolites

• Biocompatibility suitable not to induce any adverse reaction

• Degradation rate appropriate to match the tissue regeneration process

• Narrow pore size distribution to allow cells to have a sufficient space to grow


When the adhered cells increase in number, they begin to enter the internal pores of the scaffold. If the porosity and interconnection between the pores are good, the cells grow and colonize the entire scaffold releasing their extracellular matrix. The upper layer of cells consumes more oxygen and nutrients, thus limiting the amount available for the cells that are migrating into the scaffold; the maximum depth at which cells can survive corresponds to the depth of cellular penetration. We studied many types of both self-supported and hybrid PLA-containing zeolitic membranes (MMMs) to study interactions with different types of normal [22] or carcinogenic (MDA-MB-231 [23] and MCF-7 [24]) cells. Initial cell tethering and filopodia exploration are followed by lamellipodia ruffling, membrane activity, and cell spreading. With time endogenous matrix is secreted by the cells, and matrix assembly sites form on the ventral plasma biological membrane. Later, with increased integrin recruitment, these early cell-matrix contacts form anchoring focal complexes at the lamellipodium leading edge that are reinforced intracellularly to form larger focal adhesion plaques upon increased intracellular and/or extracellular tension. The regulation of focal adhesion formation in adherent cells is highly complex and involves both the turnover of single integrins and the reinforcement of the adhesion plaque by protein recruitment. It follows that focal adhesions emerge as diverse protein networks that provide structural integrity and dynamically link the ECM to intracellular actin filaments, directly facilitating cell migration and spreading through continuous regulation and turnover. Furthermore, in combination with growth factor receptors, these adhesive clusters initiate signaling pathways and regulate the activity of nuclear transcription factors and processes crucial to cell growth and differentiation. The adhesion sites act as mechanosensors that form additional contact points with the underlying substratum in response. Preceding focal adhesion reinforcement, a tightly regulated series of temporospatial events occurs, mediating integrin clustering in an anisotropic manner in the direction of force. Our works underlined that the cells of both lines assume a specific morphology under the influence on the major peculiarities of scaffolds.

**Figure 7.** *Schematic representation of the antimicrobial activity of zeolite scaffolds.*

Synthetic zeolite scaffolds have been successfully applied to in vitro studies regarding both adhesion and cell growth kinetics [25] as well as to the analysis of new formulation cosmetics and foods [26] (**Figure 7**).

PLA polylactic acid polymer MOR mordenite structure MMM mixed-matrix membrane

*DOI: http://dx.doi.org/10.5772/intechopen.88422*

**Author details**

Adalgisa Tavolaro<sup>1</sup>

Cs, Italy

**49**

ITM-CNR, University of Calabria, Cs, Italy

† These authors contributed equally.

provided the original work is properly cited.

2 Department of Physics, University of Calabria, Cs, Italy

\*Address all correspondence to: a.tavolaro@itm.cnr.it

MDA-MB-231 human breast adenocarcinoma cells MCF-7 human breast ductal carcinoma cells

*Zeolites as Chameleon Biomaterials: Adsorption of Proteins, Enzymes, Foods, Drugs, Human…*

\*†, Silvia Catalano2† and Palmira Tavolaro2†

1 Research Institute on Membrane Technology, National Research Council of Italy,

3 Department of Pharmacy, Health and Nutritional Sciences, University of Calabria,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,
