3D Bioprinting tissue analogs: Current development and translational implications

Three-dimensional (3D) bioprinting is a promising and rapidly evolving technology in the field of additive manufacturing. It enables the fabrication of living cellular constructs with complex architectures that are suitable for various biomedical applications, such as tissue engineering, disease modeling, drug screening, and precision regenerative medicine. The ultimate goal of bioprinting is to produce stable, anatomically-shaped, human-scale functional organs or tissue substitutes that can be implanted. Although various bioprinting techniques have emerged to develop customized tissue-engineering substitutes over the past decade, several challenges remain in fabricating volumetric tissue constructs with complex shapes and sizes and translating the printed products into clinical practice. Thus, it is crucial to develop a successful strategy for translating research outputs into clinical practice to address the current organ and tissue crises and improve patients' quality of life. This review article discusses the challenges of the existing bioprinting processes in preparing clinically relevant tissue substitutes. It further reviews various strategies and technical feasibility to overcome the challenges that limit the fabrication of volumetric biological constructs and their translational implications. Additionally, the article highlights exciting technological advances in the 3D bioprinting of anatomically shaped tissue substitutes and suggests future research and development directions. This review aims to provide readers with insight into the state-of-the-art 3D bioprinting techniques as powerful tools in engineering functional tissues and organs

Designing vascular supportive albumen-rich composite bioink for organ 3D printing

Bioink plays a major role in 3D printing of tissues and organs. Alginate is a widely used component for bioinks but its cellular responses are limited, which limits its clinical translation. In this study, we demonstrate the printability and cellular compatibility of composite bioink consists of sodium alginate (NaAlg) and egg white, also called albumen. The experimental conditions necessary for 3D printing composite bioink were optimized by changing different concentration ratios of Albumen/NaAlg and their various physicochemical properties were studied. The structural characteristics of the 3D printed scaffold was also investigated. In vitro experiments showed that human umbilical vein endothelial cells can successfully attach to the printed scaffold and maintain high viability during the course of study. Interestingly, vascular sprouting and neovascular network formation was observed inbetween fibers within the printed scaffold. In conclusion, the results of this study demonstrate that 3D printed Albumen/NaAlg composite bioinks with favorable biological functionality hold a great potential in tissue and organ engineering

Paleokarst Reservoir Features and Their Influence on Production in the Tahe Oilfield, Tarim Basin, China

This study analyzed the characteristics of cave heights and fillings, influences on cave distribution by unconformity and geomorphology, and production control trend for geological factors. The heights and numbers of caves in different geomorphologies are basically similar. The cave heights are greater near the unconformity surface. On an average, there are higher degrees of cave development and larger cave heights in the karst slopes than in the karst highlands and karst depression. Based on core observations, four types of reservoirs were identified: unfilled caves, filled caves, open fractures and filled fractures. The formation of caves is mainly controlled by faults and underground water surfaces. Faults works obviously in the karst highland, while underground water surfaces obviously in the karst slope. Caves controlled by faults are mostly unfilled, while controlled by underground water surfaces are mostly filled with clastic sediments. According to the results from both first-day and cumulative production, production is not highly correlated with cave heights, but rather storage and connectivity of caves and fractures. Generally, wells with unfilled caves or open fractures have higher first-day and cumulative production than filled caves or fractures. The distribution of high first-day and cumulative production is consistent overall