Skulls of laboratory mice were made whole again in Baltimore with the use of bone tissue grown from human embryonic stem cells (hESCs). These experiments were conducted by a team of researchers from John Hopkins University. The scientists developed a new technique in healing critical-size defects in intramembraneous bone. These types of defects do not otherwise heal on their own. The intramembraneous bone is that flat bone type that shapes the skull. The efforts of the team are clear demonstrations of new techniques on using hESCs for tissue regeneration.

The Hopkins team controlled the mesenchymal precursor cells, which were isolated from hESCs, and cause the bone regeneration. Tiny, three-dimensional platforms or scaffolds made from biomaterials served as the structure for bone regeneration. Furthermore, the team also noted that the physical framework of cells powerfully influences the outcome of the cell development.

Nathaniel S. Hwang, Jennifer Elisseeff, and colleagues at Hopkins was able to verify that with the alteration of the materials that the scaffolding was made of, they could transfer mesenchymal precursor cells into either of the osteogenic pathways of the body. Such pathways are the: intramembraneous, those that shape the skull, jaw, and clavicle bone; or endochondral, those that build the “long” bones and engage the initial development of cartilage, which is later transformed into bone by the process of mineralization.

Mesenchymal precursor cells, which were cultured through the use of all-polymer biodegradable scaffold, developed into those that follow the endochondral lineage. On the other hand, cells, which were cultured using a composite scaffold fashioned from biodegradable polymers and a hard, gritty mineral called hydroxyapatite, progressed to the intramembraneous side.

Biomaterial scaffolds offer a three-dimensional support on which cells can multiply, differentiate, produce extracellular matrix, and develop functional tissues. Furthermore, their known composition enabled the Hopkins researchers to identify and describe the extracellular micro-environmental signals that control the lineage requirement.

Tissue culture is often a general term that refers the approach in biological research that entails the removal of tissue from an animal or plant and the transfer of which to an artificial environment in which the said tissue can persist to live and function. In tissue culture procedures, an inverted phase contrast microscope or a darkfield microscopy may be used in viewing the cells being grown.

A darkfield microscopy is fashioned with its light source and condenser located on of the stage, facing down. The objectives and turret of a darkfield microscopy, on the other hand, are located below the stage, facing up.
A good darkfield microscopy must be fashioned with a stage that offers excellent specimen location in order for the intricacies of the cultured cell to be viewed better. The condenser of a darkfield microscopy must also be pre-centered, structured to permit a long working distance, and is adjustable for optimum observation.

Moreover, the stand of a darkfield microscopy must is ergonomically designed for the comfort of the researcher. Also, a darkfield microscopy must be very durable. Furthermore, the optical and mechanical components of the darkfield microscopy must meet the requirements of the research and the researcher.Article link