微生物分子生物学作业.ppt

Modularly assembled porous cell-laden hydrogels
Bo Liu1, Yang Liu1, Andrew K. Lewis, Wei Shen*
Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
1. Introduction
tissue engineering
significances:replace diseased or lost human tissues, substitute animals for drug screening, and serve as model systems for physiological,pathological, and developmental studies.
limitations:skin and cartilage
reasons:3D nature of the cultured systems。
insufficient mass transfer in the interior regions of large avascular constructs;inhomogeneous cell seeding;difficulties in regulating distinct behavior of different cell types in the same construct.
advantages
allow perfusion, which enhances mass transfer
scaffold engineering(preformed porous scaffolds)
disadvantages
difficult to seed cells uniformly throughout preformed porous scaffolds
perfusion flow rapidly removes essential biological factors secreted by the cells attached at the surface of internal pores.
shear stress associated with perfusion flow may be non-physiological and inhibitory to tissue development
advantages
allowing uniform cell seeding
facilitating the retention of biological factors
protecting cells from exposure to non-physiological shear stress
in situ forming hydrogels
disadvantages
lack of pores and channels on the scale larger than 10 mm in these hydrogels precludes significant convective perfusion
contents
We report a modular assembly approach to creating large, porous, and cell-laden 3D constructs that have bined advantages of preformed porous scaffolds and in situ forming hydrogels。
The porosity, permeability, and pore interconnectivity of the constructs assembled from microgels having different morphological features have been examined pared。
The viability of the cells encapsulated in centimetersized constructs has been evaluated after perfusion culture.
Constructs consisting of sequentially assembled distinct microgels have been prepared, and the abilit