Patterned Three-Dimensional Encapsulation of Embryonic Stem Cells Using Dielectrophoresis and Stereolithography.

Patterned Three-Dimensional Encapsulation of Embryonic Stem Cells using Dielectrophoresis and Stereolithography.

Adv Healthc Mater. 2013 Mar; 2(3): 450-8
Bajaj P, Marchwiany D, Duarte C, Bashir R

Controlling the assembly of cells in three dimensions is very important for engineering functional tissues, drug screening, probing cell-cell/cell-matrix interactions, and studying the emergent behavior of cellular systems. Although the current methods of cell encapsulation in hydrogels can distribute them in three dimensions, these methods typically lack spatial control of multi-cellular organization and do not allow for the possibility of cell-cell contacts as seen for the native tissue. Here, we report the integration of dielectrophoresis (DEP) with stereolithography (SL) apparatus for the spatial patterning of cells on custom made gold micro-electrodes. Afterwards, they are encapsulated in poly (ethylene glycol) diacrylate (PEGDA) hydrogels of different stiffnesses. This technique can mimic the in vivo microscale tissue architecture, where the cells have a high degree of three dimensional (3D) spatial control. As a proof of concept, we show the patterning and encapsulation of mouse embryonic stem cells (mESCs) and C2C12 skeletal muscle myoblasts. mESCs show high viability in both the DEP (91.79% ± 1.4%) and the no DEP (94.27% ± 0.5%) hydrogel samples. Furthermore, we also show the patterning of mouse embryoid bodies (mEBs) and C2C12 spheroids in the hydrogels, and verify their viability. This robust and flexible in vitro platform can enable various applications in stem cell differentiation and tissue engineering by mimicking elements of the native 3D in vivo cellular micro-environment. HubMed – drug


Gene delivery of albumin binding peptide-interferon-gamma fusion protein with improved pharmacokinetic properties and sustained biological activity.

J Pharm Sci. 2013 Mar 5;
Miyakawa N, Nishikawa M, Takahashi Y, Ando M, Misaka M, Watanabe Y, Takakura Y

We have demonstrated that gene delivery of a fusion protein of mouse interferon (IFN) ? with mouse serum albumin (IFN?-MSA) was effective in prolonging the circulation half-life of IFN? in mice. However, the fusion to MSA greatly reduced the biological activity of IFN? to less than 1%. In this study, we designed IFN? fusion proteins with a 20 amino-acid long albumin-binding peptide (ABP) to prolong the in vivo half-life of IFN? without reducing its biological activity. IFN?-ABP and ABP-IFN?, two fusion proteins with the ABP being fused to the C- or N-terminal of IFN?, retained 40%-50% biological activities determined using a gamma-activated sequence-dependent luciferase assay. These fusion proteins exhibited the ability to bind to MSA. Gene delivery of IFN?-ABP or ABP-IFN? to mice using the hydrodynamic injection method resulted in a sustained concentration of IFN? in the serum compared with gene delivery of IFN?. In addition, the growth of mouse colon carcinoma CT-26 cells in the lung was efficiently inhibited by gene delivery of the IFN? fusion proteins. These results indicate that the fusion of ABP is a useful approach to achieving prolonged retention in the blood circulation through binding to serum albumin and retaining biological activity. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci. HubMed – drug


Forensic drug analysis and microfluidics.

Electrophoresis. 2013 Mar 6;
Al-Hetlani E

The analysis of drugs of abuse in microfluidic devices has the potential to provide solutions to today’s on-site analysis challenges. The use of such devices has not been limited to miniaturising conventional analytical methods used routinely in forensic laboratories; new and interesting approaches have been implemented in microfluidics and benefit from the ability to control minute amounts of liquids in the small channels. The microfluidic platforms developed so far have been used successfully to carry out single or multiple analytical processes and offer a great opportunity for new technologies for on-site drug testing. HubMed – drug