### 1.1 Article  
Designing a Synthetic 3D-Printed Knee Cartilage: FEA Model, Micro-Structure and Mechanical Characteristics  
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Osteoarthritis (OA) is the most common form of cartilage and joint disease globally [3]. It is a prevalent cause of pain, functional loss, and adult disability in Western countries [4]. OA is characterized by the gradual erosion and degeneration of the articular cartilage within the joint, which serves as a critical component in facilitating smooth joint movement. However, in OA, this protective cartilage undergoes significant changes. As the disease progresses, the cartilage begins to wear away, leading to an uneven distribution of mechanical forces within the joint. This imbalance triggers the generation of fibrocartilage, an inferior type of tissue that lacks the resilience and functionality of healthy cartilage. Concurrently, catabolic reactions ensue, further contributing to the breakdown of the cartilaginous matrix. The non-physiological mechanical stimulation of chondrocytes, the specialized cells within the cartilage responsible for maintaining its structure, adds another layer of complexity to the OA pathophysiology. These chondrocytes, instead of promoting cartilage repair, become active participants in the degenerative process [5]. Currently, the gold standards for diagnosing knee OA include clinical evaluation, medical history, and imaging techniques. Physical examination and medical history help assess symptoms, joint deformities, and previous joint-related conditions. Imaging techniques such as X-ray, Magnetic Resonance Imaging (MRI), and Computed Tomography (CT) provide valuable information on the degree and location of joint damage, confirming the diagnosis and assessing the extent of damage [6]. Unfortunately, there is currently no disease-modifying therapy available for OA, and medications aimed at treating its symptoms are generally not very successful. Therefore, the focus in cartilage treatments is to develop methods with consistent regenerative potential [7]. Animal models are crucial for bridging the gap between in vitro experiments and human clinical studies when introducing these treatments into clinical practice. Choosing an appropriate animal model involves considering multiple factors, including research funding, costs of animal purchase and housing, and the suitability of each model for specific cartilage research projects [8]. Amid increasing awareness about the importance of reducing animal experiments, cutting costs, and accelerating development timelines, our study aims to design and create synthetic cartilage tissue using computational modeling and 3D-printing technology. Three-dimensional printing, also known as additive manufacturing, involves the layer-by-layer deposition of materials to create three-dimensional objects. It is widely used in various industries for producing prototypes, customized products, and complex geometries [9]. In healthcare, 3D printing is utilized for creating patient-specific implants [10], prosthetics, and anatomical models for surgical planning [11]. While previous 3D-printed anatomical models have achieved similarities to human tissue in shape, they have not fully replicated mechanical responsiveness [12]. Digital Anatomy Printing is an advanced form of 3D printing specifically designed for the medical field. It involves the use of specialized materials that mimic the properties of human tissues, allowing for the creation of highly detailed anatomical models [13]. Digital Anatomy Printing bridges the gap between traditional 3D printing and BioPrinting by simulating the look and feel of human tissues without the ability to create functional living tissues [14]. On the other hand, BioPrinting stands out for its ability to create functional living tissues and organs, ushering in a new era of possibilities in the fields of medicine and biotechnology [15].