A novel core–shell microcapsule system is developed in this study to mimic the miniaturized 3D architecture of pre-hatching embryos with an aqueous liquid-like core of embryonic cells and a hydrogel-shell of zona pellucida. This is done by microfabricating a non-planar microfluidic flow-focusing device that enables one-step generation of microcapsules with an alginate hydrogel shell and an aqueous liquid core of cells from two aqueous fluids. Mouse embryonic stem (ES) cells encapsulated in the liquid core are found to survive well (>92%). Moreover, ~20 ES cells in the core can proliferate to form a single ES cell aggregate in each microcapsule within 7 days while at least a few hundred cells are usually needed by the commonly used hanging-drop method to form an embryoid body (EB) in each hanging drop. Quantitative RT-PCR analyses show significantly higher expression of pluripotency marker genes in the 3D aggregated ES cells compared to the cells under 2D culture. The aggregated ES cells can be efficiently differentiated into beating cardiomyocytes using a small molecule (cardiogenol C) without complex combination of multiple growth factors. Taken together, the novel 3D microfluidic and pre-hatching embryo-like microcapsule systems are of importance to facilitate in vitro culture of pluripotent stem cells for their ever-increasing use in modern cell-based medicine.

We report novel robust resin acid-derived antimicrobial agents that exhibit excellent antimicrobial activities against a broad spectrum of bacteria (6 Gram-positive and 7 Gram-negative) with selective lysis of microbial membranes over mammalian membranes. Our results indicate that hydrophobicity and unique structures of resin acids can be determining factors in dictating the antimicrobial activity.

In this study, we report the preparation of a novel microcapsule of ∼100 μm with a liquid (as compared to a solid-like alginate hydrogel) core and an alginate–chitosan–alginate (ACA) shell for encapsulation and culture of embryonic stem (ES) cells in the miniaturized 3D space of the liquid core. Murine R1 ES cells cultured in the microcapsules were found to survive (>90%) well and proliferate to form either a single aggregate of pluripotent cells or an embryoid body (EB) of more differentiated cells in each microcapsule within 7 days, depending on the culture medium used. This novel microcapsule technology allows massive production of the cell aggregates or EBs of uniform size and controllable pluripotency, which is important for the practical application of stem cell based therapy. Moreover, the semipermeable ACA shell was found to significantly reduce immunoglobulin G (IgG) binding to the encapsulated cells by up to 8.2 times, compared to non-encapsulated cardiac fibroblasts, mesenchymal stem cells, and ES cells. This reduction should minimize inflammatory and immune responses induced damage to the cells implanted in vivo because IgG binding is an important first step of the undesired host responses. Therefore, the ACA microcapsule with selective shell permeability should be of importance to advance the emerging cell-based medicine.