**Gelatin and Collagen Nanofiber Scaffolds for Tissue Engineering Gelatin and Collagen Nanofiber Scaffolds for Tissue Engineering**

DOI: 10.5772/intechopen.73316

Daniella Alejandra Pompa Monroy, José Manuel Cornejo Bravo, Irma Esthela Soria Mercado and Luis Jesús Villarreal Gómez Daniella Alejandra Pompa Monroy, José Manuel Cornejo Bravo, Irma Esthela Soria Mercado and Luis Jesús Villarreal Gómez Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.73316

#### **Abstract**

One of the main complications that can present a person with second and third degree burns is the possibility of being infected by opportunistic bacteria or viruses that are present in the environment. Nowadays, the majority of the burn injuries are treated with conventional gauze, which involves a high probability of infection and pain for the patient being treated with this method. In order to obtain low-cost scaffolds, natural and abundant polymers were used such as gelatin (GEL) and collagen (COL). The GEL functions as a base scaffold, stable and flexible, and also biocompatible because it is a byproduct of the partial hydrolysis of COL, which is an indispensable component for the stability of the cell membrane and it is present in great extent in the human epithelium.

**Keywords:** cutaneous dressings, polymer, gelatin, collagen, bioactivity

#### **1. Introduction**

Electrospinning technique is used for the production of fibers at nanometer scale, which has been used previously for the production of cutaneous dressings and a great variety of scaffolds with biomedical interest. It consists of the injection of a polymer solution properly homogenized in a polar solvent, in order to obtain a conductive material; by applying a current of the order of kilovolts (kV), it allows the solution to form a Taylor cone, which permits the formation of fibers. Another widely used technique is the electrospray that starts from the same principle of electrospinning but through a solution that allows the formation of suspended nanoparticles in the solvent, so that they are deposited on the collector (**Figure 1**) [1].

© 2016 The Author(s). Licensee InTech. 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, provided the original work is properly cited. © 2018 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, provided the original work is properly cited.

**2. Gelatin electrospun scaffolds**

toxic effect of residual glutaraldehyde on cells [6].

systems for bioactive molecules within the nanofiber matrices [7].

provides predetermined mechanical properties [8].

GEL nanofibers have been prepared using an electrospinning process in previous studies. To improve water-resistant capacity and thermomechanical performance for potential biomedical applications, GEL nanofibers were cross-linked with glutaraldehyde-saturated steam at room temperature. Exposure of this nanofibrous material to the glutaraldehyde vapor was performed for 3 days to provide sufficient cross-linking to preserve the fibrous morphology assayed by immersion at 37°C warm water. On the other hand, cross-linking also led to improved thermostability and substantial improvement in mechanical properties. The denaturation temperature corresponding to the transition from the helix to the coiled structure of the air-dried samples increased by about 11°C and the tensile strength and modulus were nearly 10 times greater than those of the electrospun GEL fibers. In addition, cytotoxicity was evaluated based on a cell proliferation study by culturing human dermal fibroblasts on the fibrous scaffolds of cross-linked GEL for 1, 3, 5, and 7 days. It was found that cell growth occurred and increased almost linearly over the course of the entire cell culture period. Initial inhibition of cell growth on the cross-linked fibrous substrate of GEL suggested some cyto-

Gelatin and Collagen Nanofiber Scaffolds for Tissue Engineering

http://dx.doi.org/10.5772/intechopen.73316

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The GEL was successfully electrospun using a solvent based on ethyl acetate, acetic acid, and water. Since natural polymers including GEL have limited solubility in water, toxic or highly acidic solvents are usually used to dissolve them for electrospinning. Instead of using such solvents, ethyl acetate was used with acetic acid in water; the beneficial effect of its use was investigated in terms of the spinning capacity of the nanofiber and the acidity of the solvent. It was found that the substitution of acetic acid with ethyl acetate improved the spinning capacity of the nanofiber by reducing the surface tension of the solution, as well as increasing the pH of the solvent significantly. The optimum composition of the co-solvent was found to correspond to a ratio of ethyl acetate to acetic acid in a ratio of 2:3. Under this solvent condition, the GEL could be dissolved at concentrations up to 11% by weight and successfully electrospun to produce nanofibers of various diameters (47–145 nm on average) depending on the GEL concentration. The water-based co-solvent method proposed herein may be useful for generating other natural nanofibrous polymers, as well as being applicable in delivery

In another study, electrospinning was performed in aqueous GEL solution, increasing the spinning temperature. To improve stability and mechanical properties in the wet state, the GEL nanofibrous membrane is chemically reticulated by 1-ethyl-3-dimethylaminopropylcarbodiimide hydrochloride and N-hydroxyl succinimide. The crosslinker concentration was optimized by measuring the degree of swelling and weight loss. The nanofibrous structure of the membrane was maintained after lyophilization, although the fibers were crimped and conglutinated. The tensile test revealed that the hydrated membrane becomes flexible and

It can be said that electrospinning has been one of the simplest, most versatile, and promising processes for producing continuous nanofibers. In the case of GEL, this polymer has been

**Figure 1.** Electrospinning/electrospray scheme with polymer solutions.

Generally, the polymers used in electrospinning for biomedical applications are biodegradable and biocompatible; thus, they can be in contact with physiological medium without generating undesired reactions. Among them is GEL, which is a natural polymer obtained from collagen (COL) which is a protein obtained from the connective tissue of animals when boiled in water, GEL is a very useful polymer in electrospinning because of its ability to produce fibers of nanometric scale independently of the changes in the temperature and humidity of the environment, for this reason it was used as a base for the formation of bioactive electrospun [2].

Electrospinning has recently been extensively studied; it is a well-known technique for the manufacture of nanoscale fibers because of its various advantages such as high surfacevolume ratio, adjustable porosity, and ease of surface functionalization. The resulting fibers are extremely useful for applications in the fields of tissue engineering, drug delivery, and wound dressing. In addition to the morphological, physical, and chemical properties, electrospun scaffolds are often evaluated through various cell studies. Researchers have adopted approaches such as surface modification and drug loading to improve scaffold ownership and function [3].

The electrospinning technique has been used as an efficient and accessible method for the manufacture of nanofibers with a wide variety of applications in the fields of pharmaceutics and medicine. Among the most outstanding applications, we can see wound dressings, drug delivery systems, or tissue engineering scaffolds [4]. Animal polysaccharides such as chitosan, hyaluronic acid, heparin, and collagen have been studied with this technique; these compounds are natural biopolymers with numerous advantages for biomedical applications such as biocompatibility, biodegradability, nonantigenicity, and nontoxicity [5].
