In tissue engineering, the pivotal role of scaffolds is underscored, serving as key elements to emulate the native extracellular matrix. These scaffolds must provide structural integrity and support and supply electrical, mechanical, and chemical cues for cell and tissue growth. Notably, electrical conductivity plays a crucial role when dealing with tissues like bone, spinal, neural, and cardiac tissues. However, the typical materials used as tissue engineering scaffolds are predominantly polymers, which generally characteristically feature poor electrical conductivity. Therefore, it is often necessary to incorporate conductive materials into the polymeric matrix to yield electrically conductive scaffolds and further enable electrical stimulation. Among different conductive materials, carbon nanomaterials have attracted significant attention in developing conductive tissue engineering scaffolds, demonstrating excellent biocompatibility and bioactivity in both in vitro and in vivo settings. This article aims to comprehensively review the current landscape of carbon-based conductive scaffolds, with a specific focus on their role in advancing tissue engineering for the regeneration and maturation of functional tissues, emphasizing the application of electrical stimulation. This review highlights the versatility of carbon-based conductive scaffolds and addresses existing challenges and prospects, shedding light on the trajectory of innovative conductive scaffold development in tissue engineering.
Amid the escalating prevalence of eye diseases and the intricate nature of the eye as a crucial target organ for drug delivery, researchers face significant challenges in developing delivery systems tailored specifically for ocular complications. Addressing the gaps in the current conventional ocular drug delivery system (ODDS) is crucial and this can be achieved by incorporating polymers while designing newer ODDS. This review aims to offer a concise overview of the diverse polymers utilized in the development of ODDS, designed to address various eye conditions and disorders, enhance treatment outcomes, and ensure patient adherence. Introducing the anatomy of the eye and different ocular routes of administration, alongside the barriers encountered, this review presents polymer-based ODDS, renowned for their unique properties facilitating the engineering of specialized devices for enhanced drug delivery. Further discussions delve into the applications of polymers in ophthalmology. Emphasis is placed on emerging polymer-based technologies available in the market for treating ocular diseases, underscoring their potential for revolutionizing ocular healthcare. The review also addresses challenges in translating these advancements into clinical practice, while highlighting the versatility of polymers in treating diverse eye diseases and disorders through customizable properties and sustained drug delivery.
Bone defect is a common clinical disease. Due to the uncertainty of trauma or infection areas, customized size features are often required for bone substitutes. By inspiration of the natural bone structure, this study designs porous scaffolds with a biomimetic design perspective by using different inner and outer pore units. The outer pore units adopt body-centered cubic (BCC) structure to simulate the weight-bearing function of human cortical bone, while inner pore units using I-Wrapped Package structure, a kind of three periods minimum surface, to obtain a good permeability and simulates the inner layer of cancellous bone. To further regulate the overall modulus of the scaffold within the range of natural bone modulus in the human body, the scaffold was designed to axial gradient structure. Compression experiments were conducted, and the results indicated that when the volume fraction linearly increased from 20% to 50%, the Young’s modulus was close to the cortical bone modulus in the human body. In vitro cell experiments further proved that osteoblasts have good cellular activity and spreading morphology on the surface of this scaffold. The customized 3D-printed heterogeneous porous titanium scaffold has great application potential in bone tissue engineering.
This manuscript aims to three-dimensional bioprint and evaluate new polymer composite scaffolds based on synthesized poly(ethylene glycol) dimethacrylate (PEGDMA) as well as methyl cellulose and gelatin. The PEGDMA was synthesized by a simple microwave-assisted method using three distinct molecular weights (MWs) of poly(ethylene glycol) (PEG), 3, 6, and 12 kDa, and methacrylic anhydride. The percent functionalization of the PEGDMA was analyzed using the nuclear magnetic resonance spectrum, and the theoretical calculations indicated that over 50% of methacrylation was achieved in all samples, with the PEGDMA synthesized from 6 kDa PEG surpassing 66% methacrylation. These three PEGDMA-based bioinks were investigated for their suitability for bioprinting scaffolds. It was observed that lower MW PEGDMA resulted in a higher degree of crosslinking, leading to more stable composite scaffolds. However, higher crosslinking degree did not support long-term cell viability when encapsulated with cells. Higher MW PEGDMA showed higher cell viability over time though overall stability was lower. Synthesized PEGDMA with 6 kDa PEG showed both stability and longterm cell viability after postprinting. Over 80% of cell viability was maintained for a 7-day study period, showing potential use in tissue engineering applications as a cell delivery vehicle.