Combining cell sheet technology and electrospun scaffolding for engineered tubular, aligned, and contractile blood vessels.

Herein we combine cell sheet technology and electrospun scaffolding to rapidly generate circumferentially aligned tubular constructs of human aortic smooth muscles cells with contractile gene expression for use as tissue engineered blood vessel media. Smooth muscle cells cultured on micropatterned and N-isopropylacrylamide-grafted (pNIPAm) polydimethylsiloxane (PDMS), a small portion of which was covered by aligned electrospun scaffolding, resulted in a single sheet of unidirectionally aligned cells. Upon cooling to room temperature, the scaffold, its adherent cells, and the remaining cell sheet detached and were collected on a mandrel to generating tubular constructs with circumferentially aligned smooth muscle cells which possess contractile gene expression and a single layer of electrospun scaffold as an analogue to a small diameter blood vessel's internal elastic lamina (IEL).

High water content hydrogel with super high refractive index.

Transparent, high water content (>65%), and cytocompatible hydrogels, which also possess super high refractive indices (RI > 1.5), are needed for ophthalmological applications. Most hydrogels can achieve either high RI or high water content but not both in the same system because water is a low RI material.

Argon-plasma-induced ultrathin thermal grafting of thermoresponsive pNIPAm coating for contractile patterned human SMC sheet engineering.

A new method for ultrathin grafting of pNIPAm on PDMS surfaces is introduced that employs plasma activation of the surface followed by thermal polymerization. This method is optimized for human primary SMC attachment and subsequent intact cell sheet detachment by lowering the temperature. The contractile gene expression of the cells showed that the contractile phenotype of the SMCs which is induced by aligning the cells through micropatterning is more preserved after thermoresponsive cell sheet detachment in contrast with enzymatic detachment.

Impact of endothelial cells on 3D cultured smooth muscle cells in a biomimetic hydrogel.

For the development of vascular tissue engineering, the impact of endothelial cells (ECs) on smooth muscle cell (SMC) spreading, proliferation, and differentiation is explored in the current study using a coculture model. In this coculture model, SMCs were encapsulated in a biomimetic hydrogel based on methacrylated dextran-graft-lysine (Dex-MA-LA) and methacrylamide-modified gelatin (Gel-MA), and exposed to a monolayer of ECs. With EC coculture, SMC proliferation in 3D hydrogel was promoted at initial period, and the formation of denser cellular networks was enhanced.

Aligned 3D human aortic smooth muscle tissue via layer by layer technique inside microchannels with novel combination of collagen and oxidized alginate hydrogel.

Tissue engineering of the small diameter blood vessel medial layer has been challenging. Recreation of the circumferentially aligned multilayer smooth muscle tissue has been one of the major technical difficulties. Some research has utilized cyclic stress to align smooth muscle cells (SMCs) but due to the long time conditioning needed, it was not possible to use primary human cells because of expeditious senescence occurred .

Intracardiac invasive thymoma presenting as superior vena cava syndrome.

A case of invasive thymoma with intra-caval and intracardiac extension presenting as superior vena cava syndrome is reported. The tumor is excised on cardiopulmonary bypass, and superior vena cava is bypassed using a Dacron graft (DuPont, Wilmington, DE). Five-year follow-up of the patient showed a patent graft.

Biomimetic control of vascular smooth muscle cell morphology and phenotype for functional tissue-engineered small-diameter blood vessels.

Small-diameter blood vessel substitutes are urgently needed for patients requiring replacements of their coronary and below-the-knee vessels and for better arteriovenous dialysis shunts. Circulatory diseases, especially those arising from atherosclerosis, are the predominant cause of mortality and morbidity in the developed world. Current therapies include the use of autologous vessels or synthetic materials as vessel replacements.