FABRICATION OF HYBRID SCAFFOLD FOR DRUG SCREENING APPLICATIONS

Abstract

The advancement in biomedical sciences and translational biotechnology creates more and more advanced and reliable new methods and techniques to improve these fields worldwide. Conventionally, cancer biology research has focused mainly on 2D cultures and in vivo animal models to examine the effect of anti-cancer drugs as efficient prospective therapeutic drugs; this pre-clinical testing takes place prior to human clinical trials . The contrast arising in cellular behavior between 2D cultures and actual tumors is well acknowledged. This difference can be ascribed to the varying interactions that regulate gene expression occurring in 2D environment than in a more natural in vivo surrounding. A notable case is that cells grown in 2D culture lack the spatial gradient of nutrients found in vivo environment, critical for processes like biological differentiation, organ development and tumor progression, and many other natural phenomena. Thus, it is not hard to wonder why so many facets of tumorigenesis are still concealed from us. However, 3D scaffolds have proven to mimic in vivo conditions more accurately, which is beneficial to precisely analyze the cellular response against anti-cancer drugs. To engineer an ideal 3D tumor model, it should be able to reproduce all the complex interactions transpiring between cell and ECM. So in an attempt to achieve it here, a realistic 3D Bioengineered Hybrid model composed of Electrospun nanofibrous scaffold and hydrogel was fabricated, which is capable of partially reproducing tumor niche in vivo. Electrospinning was chosen as it is a versatile polymer processing method through which fibers of micro/nano dimensions are produced. These electrospun fibers produces a non-woven fabric that to a great extent mimics the native ECM fibrous matrix and offers morphological cues resulting in enhanced cellular responses. However, Nanofibres produced by conventional 2D electrospinning are practically 2D dense mats rather than 3D. To overcome this limitation, wet electrospinning was implemented in which silk fibroin nanofibres are collected in a liquid bath instead of a solid ground collector, which improves cellular infiltration because of its highly porous nature. To come up with a conducive biochemical environment and add hydrophilicity to our silk nanofibrous scaffold, silk nanofibres were impregnated with photopolymerizable GelMA hydrogel. These hybrid scaffolds have been previously shown to recapitulate tumor microenvironments, especially conducive to the metastasis process. The effect of Niclosamide, an anti-cancer drug, was examined on cancer cells cultured in our 3D hybrid scaffold by performing MTT assay and comparing the IC50 values between the 3D hybrid scaffold and 2D culture. Niclosamide which was previously recognized as an anthelminthic drug, is considered by many reports as a potent anti-cancer drug owing to its efficacy in impeding multiple cancers and its concreted interference in multiple cell signaling pathways, making it difficult for cancer cells to acquire resistance.