3 minute read
Adaeze Eze
Mentor: Naznin Sultana Texas Undergraduate Medical Academy
Introduction: Recent studies have placed a focus on the polymer pectin due to its inexpensive cost combined with its diverse biological properties. Commercially, pectins are extracted from plant materials such as citrus peel, apple pomace, and sugar beets. The functions of pectin are determined by the source that the polymer is derived or extracted and their distinct chemical structures. Properties of pectin, such as its non-toxicity, emulsion behavior, diverse chemical composition, biocompatibility, and high stability, antibacterial activity, make it a desired polymer for use in various applications. The multifunctional component of pectin has allowed it to provide numerous target sites for chemical modifications with compounds and other biopolymers. Chitosan is a natural polysaccharide that is non-toxic, biocompatible, and biodegradable and hence is promising to use as a scaffold material in bone tissue engineering. Tissue engineering or tissue regeneration associates living cells with biodegradable materials and/or bioactive components. There are several techniques to fabricate membranes or scaffolds from polymer solutions. Thermally-induced phase separation (TIPS) and freeze-drying technique is another promising technique to produce 3-D scaffolds (Sultana and Wang, 2008; Sultana and Wang, 2012). The need for synthetic tissue with similar biological and chemical properties to natural tissue has increased due to the limited availability of natural tissue grafts. This limitation is the main motivation for developing artificial composite materials. Tissue engineering has provided a new approach for treating various tissue ailments. Therefore, recent research has focused on biodegradable natural polymers-based composite scaffolds as an alternative strategy to remediate skin regeneration. The hypothesis of this research is that the Chitosan/pectin-based scaffold can be successfully applied to regenerate skin tissue. The specific aims of the project were to fabricate Chitosan/Pectin scaffolds using TIPS and freeze-drying techniques and to characterize the morphology, porosity, and cytotoxicity using human skin fibroblasts (HSF). Materials and Methods: Chitosan with medium molecular weight and pectin from a citrus peel (Pc, galacturonic acid content of 80.2%, methoxylation degree of 7.6%, and M, of 45kDa) were purchased from Sigma-Aldrich. The fabrication technique was described previously (Eze et al., 2020). The amount of pectin added was 0.05g and 0.1 g, respectively. The morphology of a small section of each sample is examined by SEM (Hitachi TM3000, Japan) at an accelerating voltage of 15 kV (Chung, 2016) to confirm the morphology. Cytotoxicity testing was evaluated by using HSF cells in vitro. Results and Discussion: Recent studies have placed a focus on the polymer pectin due to its inexpensive cost combined with its biological properties that enables it to be used in various applications such as pharmacological and food applications. Pectins make up an essential part that is needed for the development of plants. The polymer helps to provide intercellular adhesion, rigidity, turgidity, and mechanical resistance for the cell walls of plants. The multifunctional component of pectin has allowed it to provide numerous target sites for chemical modifications (Pereira et al., 2018). The properties of pectin, such as its non-toxicity, emulsion behavior, diverse chemical composition, biocompatibility, and high stability, enable it to be a commonly used polymer. Industrially, pectin is used for various types of applications such as food manufacturing, drug delivery, and tissue engineering. Porous pectin and Chitosan-based tissue scaffolds were successfully fabricated using a freeze-drying technique and evaluated for different required properties. In-vitro cell culture studies using Human Skin Fibroblasts suggest that the scaffolds are non-toxic to human cells and could potentially be used in skin regeneration (Figure 1).
Figure 1: In vitro HSF cell culture on the Pectin based scaffolds
Conclusion(s) or Summary: Anti-cytotoxic effects of the pectin in the pectin-chitosan composite were beneficial to the overall health and survival rate of human skin fibroblast cells. Pectin has the ability to reduce the cellular cytotoxicity levels to support the immune response when using the chitosan-pectin composite for tissue engineering scaffolds.
References:
Sultana N, Wang M. 2008. Fabrication of HA/PHBV composite scaffolds through the emulsion freezing/freeze-drying process and characterization of the scaffolds. J Mater Sci Mater Med 19: 2555-2561. Sultana N, Wang M. 2012. PHBV/PLLA-based composite scaffolds fabricated using an emulsion freezing/freeze-drying technique for bone tissue engineering: surface modification and in vitro biological evaluation. Biofabrication. 2012;4:015003 Pereira, F. R., Barrias C. C., Bartolo, J. P., & Granja L. P. (2018). Cell-instructive pectin hydrogels crosslinked via thiolnorbornene photo-click chemistry for skin tissue engineering. Acta Biomaterialia, 282-293. https://doi.org/10.1016/j.actbio.2017.11.016
