Highly Porous Type II Collagen-Containing Scaffolds for Enhanced Cartilage Repair with Reduced Hypertrophic Cartilage Formation

An injectable and 3D printable pro-chondrogenic hyaluronic acid and collagen type II composite hydrogel for the repair of articular cartilage defects

Current treatments for repairing articular cartilage defects are limited. However, pro-chondrogenic hydrogels formulated using articular cartilage matrix components (such as hyaluronic acid (HA) and collagen type II (Col II)), offer a potential solution if they could be injected into the defect via minimally invasive arthroscopic procedures, or used as bioinks to 3D print patient-specific customised regenerative scaffolds-potentially combined with cells. However, HA and Col II are difficult to incorporate into injectable/3D printable hydrogels due to poor physicochemical properties. This study aimed to overcome this by developing an articular cartilage matrix-inspired pro-chondrogenic hydrogel with improved physicochemical properties for both injectable and 3D printing (3DP) applications. To achieve this, HA was methacrylated to improve mechanical properties and mixed in a 1:1 ratio with Col I, a Col I/Col II blend or Col II. Col I possesses superior mechanical properties to Col II and so was hypothesised to enhance hydrogel mechanical properties. Rheological analysis showed that the pre-gels had viscoelastic and shear thinning properties. Subsequent physicochemical analysis of the crosslinked hydrogels showed that Col II inclusion resulted in a more swollen and softer polymer network, without affecting degradation time. While all hydrogels exhibited exemplary injectability, only the Col I-containing hydrogels had sufficient mechanical stability for 3DP applications. To facilitate 3DP of multi-layered scaffolds using methacrylated HA (MeHA)-Col I and MeHA-Col I/Col II, additional mechanical support in the form of a gelatin slurry support bath freeform reversible embedding of suspended hydrogels was utilised. Biological analysis revealed that Col II inclusion enhanced hydrogel-embedded MSC chondrogenesis, thus MeHA-Col II was selected as the optimal injectable hydrogel, and MeHA-Col I/Col II as the preferred bioink. In summary, this study demonstrates how tailoring biomaterial composition and physicochemical properties enables development of pro-chondrogenic hydrogels with potential for minimally invasive delivery to injured articular joints or 3DP of customised regenerative implants for cartilage repair.

Simple Technique for Microscopic Evaluation of Active Cellular Invasion into 3D Hydrogel Constructs

Materials that are evaluated for bioengineering purposes are carefully tested to evaluate cellular interactions with respect to biocompatibility and in some cases cell differentiation. A key perspective that is often considered is the ability for decellularized synthetic or natural based matrices to facilitate cell migration or tissue ingrowth. Current methods of measuring cell migration range from simple scratch assays to Boyden chamber inserts and fluorescent imaging of seeded spheroids. Many of these methods require tissue processing for histological analysis and fixing and staining for imaging, which can be difficult and dependent on the stability of the hydrogel subject. Herein we present a simple platform that can be manufactured using 3D printing and easily applied to in vitro cell culture, allowing the researcher to image live cellular migration into a cellular materials. We found this to be an adaptable, cheap, and replicable technique to evaluate cellular interaction that has applications in the research and development of hydrogels for tissue engineering purposes.

Function of the Long Noncoding RNAs in Hepatocellular Carcinoma: Classification, Molecular Mechanisms, and Significant Therapeutic Potentials

Hepatocellular carcinoma (HCC) is the most common and serious type of primary liver cancer. HCC patients have a high death rate and poor prognosis due to the lack of clear signs and inadequate treatment interventions. However, the molecular pathways that underpin HCC pathogenesis remain unclear. Long non-coding RNAs (lncRNAs), a new type of RNAs, have been found to play important roles in HCC. LncRNAs have the ability to influence gene expression and protein activity. Dysregulation of lncRNAs has been linked to a growing number of liver disorders, including HCC. As a result, improved understanding of lncRNAs could lead to new insights into HCC etiology, as well as new approaches for the early detection and treatment of HCC. The latest results with respect to the role of lncRNAs in controlling multiple pathways of HCC were summarized in this study. The processes by which lncRNAs influence HCC advancement by interacting with chromatin, RNAs, and proteins at the epigenetic, transcriptional, and post-transcriptional levels were examined. This critical review also highlights recent breakthroughs in lncRNA signaling pathways in HCC progression, shedding light on the potential applications of lncRNAs for HCC diagnosis and therapy.