Acceleration of vascular sprouting from fabricated perfusable vascular-like structures.

Fabrication of vascular networks is essential for engineering three-dimensional thick tissues and organs in the emerging fields of tissue engineering and regenerative medicine. In this study, we describe the fabrication of perfusable vascular-like structures by transferring endothelial cells using an electrochemical reaction as well as acceleration of subsequent endothelial sprouting by two stimuli: phorbol 12-myristate 13-acetate (PMA) and fluidic shear stress. The electrochemical transfer of cells was achieved using an oligopeptide that formed a dense molecular layer on a gold surface and was then electrochemically desorbed from the surface.

Rapid engineering of endothelial cell-lined vascular-like structures in in situ crosslinkable hydrogels.

Fabrication of perfusable vascular networks in vitro is one of the most critical challenges in the advancement of tissue engineering. Because cells consume oxygen and nutrients during the fabrication process, a rapid fabrication approach is necessary to construct cell-dense vital tissues and organs, such as the liver. In this study, we propose a rapid molding process using an in situ crosslinkable hydrogel and electrochemical cell transfer for the fabrication of perfusable vascular structures.

Fabrication of perfusable vasculatures by using micromolding and electrochemical cell transfer.

Fabrication of vascular networks for the delivery of oxygen and nutrients is a critical issue when engineering 3-dimensional tissues and organs. This study describes an approach that involves micromolding and electrochemical cell transfer and can be employed to fabricate endothelial cell-lined vascular-like structures that are precisely aligned at micrometer intervals in a photocrosslinkable gelatin hydrogel. Subsequent perfusion culture induces the migration and sprouting of endothelial cells in the hydrogel and facilitates luminal structure formation.

Cell-adhesive and cell-repulsive zwitterionic oligopeptides for micropatterning and rapid electrochemical detachment of cells.

In this study, we describe the development of oligopeptide-modified cell culture surfaces from which adherent cells can be rapidly detached by application of an electrical stimulus. An oligopeptide, CGGGKEKEKEK, was designed with a terminal cysteine residue to mediate binding to a gold surface via a gold-thiolate bond. The peptide forms a self-assembled monolayer through the electrostatic force between the sequence of alternating charged glutamic acid (E) and lysine (K) residues.

Electrical detachment of cells for engineering capillary-like structures in a photocrosslinkable hydrogel.

A major challenge in tissue engineering is the fabrication of vascular networks capable of delivering oxygen and nutrients throughout tissue constructs. Because cells located more than a few hundred micrometers away from the nearest capillaries are susceptible to oxygen shortages, it is crucial to develop microscale technologies for engineering a vascular structure in three-dimensionally thick tissues. This study describes an electrochemical approach for fabricating capillary-like structures precisely aligned within micrometer distances, the internal surfaces of which are covered with vascular endothelial cells in a photocrosslinkable hydrogel.

Tissue engineering based on electrochemical desorption of an RGD-containing oligopeptide.

This paper describes a non-invasive approach for efficient detachment of cells adhered to a gold substrate via a specific oligopeptide. Detachment is effected by an electrical stimulus. The oligopeptide contains cysteine, which spontaneously forms a gold-thiolate bond on a gold surface.

SAM-based cell transfer to photopatterned hydrogels for microengineering vascular-like structures.

A major challenge in tissue engineering is to reproduce the native 3D microvascular architecture fundamental for in vivo functions. Current approaches still lack a network of perfusable vessels with native 3D structural organization. Here we present a new method combining self-assembled monolayer (SAM)-based cell transfer and gelatin methacrylate hydrogel photopatterning techniques for microengineering vascular structures.