In this issue

Tissue engineering – to scaffold or not to scaffold

Demirbag et al., Biotechnol. J. 2011, 6, 1437–1453.

Tissue engineering refers to the in vitro culture of tissues and organs, and offers the promise of replacing worn/damaged body parts that are vital to our survival and wellbeing. There are three basic components to tissue engineering: cells, bioactive agents to induce cells to function, and scaffolds that house the cells and act as the substitute for the damaged tissue. The question “to scaffold or not to scaffold” is however, dependent on various parameters, as each has its relative advantages and disadvantages. In this issue, using various applications as examples (such as cartilage, bone and nerve regeneration), Hasirci and colleagues provide a comprehensive review on cell-based therapies with or without scaffolds. This review serves as an excellent entry point and literature reference to those wishing to understand the relative merits of “to scaffold” or “not to scaffold” in tissue engineering.

original image 10.1002/biot.201100261

Cell-based biosensors

Zhu et al., Biotechnol. J. 2011, 6, 1466–1476.

Cell-based biosensors can be applied in environmental monitoring, drug screening as well as for clinical diagnostics. Compared to molecular-based biosensors, cell-based biosensors mimic physiological situations more closely, show enhanced specificity and sensitivity, and can detect unknown compounds and toxins. Current limitations include weak cell-substrate attachment, the 2D cell microenvironment, and limited shelf life. To address these limitations, one can encapsulate cells in hydrogels to provide a 3D environment, which can be combined with novel biomaterials and microtechnologies. In this issue, TianJian Lu, Feng Xu (Xi'an Jiaotong University, China) and collaborators present the state of the art in hydrogel-based cell-based biosensor development and review remaining challenges as well as potential solutions to these problems.

original image 10.1002/biot.201100098

Automated microtissue production for drug testing

Drewitz et al., Biotechnol. J. 2011, 6, 1488–1496.

Although it is widely recognized that 2D cell cultures do not reflect the physiological environment of cells in native tissues, 3D culture systems are not commonly used in pre-clinical drug testing. This is mostly due to a lack of automated high-throughput systems for 3D cultivation. In this issue, researchers at InSphero AG, Z�rich, Switzerland, show the robustness of spherical microtissues (multicellular spheroids) production and drug testing in a 96-well hanging-drop multiwell plate format, on a standard 96-well channel robotic platform. Microtissue models derived from six different cell lines were produced and characterized according to their growth profile and morphology. The presented technology will aid the implementation of more organotypic model systems at early stages of the drug discovery process.

original image 10.1002/biot.201100290