Biomedical subjects

Renji Zhang

Publications and source records attributed to Renji Zhang.

5 recordsLinked to original sources

PubMed2006

Generation of three-dimensional hepatocyte/gelatin structures with rapid prototyping system.

Using rapid prototyping technology, three-dimensional (3D) structures composed of hepatocytes and gelatin hydrogel have been formed. This technique employs a highly accurate 3D micropositioning system with a pressure-controlled syringe to deposit cell/biomaterial structures with a lateral resolution of 10 microm. The pressure-activated micro-syringe is equipped with a fine-bore exit needle for which a wide variety of 3D patterns with different arrays of channels (through-holes) were created. More than 30 layers of a hepatocyte/gelatin mixture were laminated into a high spacial structure using this method. The laminated hepatocytes remained viable and performed biological functions in the construct for more than 2 months. The rapid prototyping technology offers potential for eventual high-throughout production of artificial human tissues or organs.

Animals↗

PubMed2005

Fabrication of viable tissue-engineered constructs with 3D cell-assembly technique.

We have recently developed an organ manufacturing technique that enables us to form cell/biomaterial complex three-dimensional (3D) architectures in designed patterns. This technique employs a highly accurate 3D micropositioning system with a pressue-controlled syringe to deposit cell/biomaterial structures with a lateral resolution of 10 microm. The pressure-activated micro-syringe is equipped with a fine-bore exit needle using which a wide variety of 3D patterns with different arrays of channels (through-holes) were created. The channels can supply living cells with nutrients and allow removing the cell metabolites. The embedded cells remain viable and perform biological functions as long as the 3D structures are retained. The new technology has the potential for eventual high-throughput production of artificial human tissues and organs.

Animals↗

PubMed2005

Preparation and evaluation of ammonia-treated collagen/chitosan matrices for liver tissue engineering.

To further enhance the properties of existing collagen/chitosan scaffolds for liver tissue engineering, a very simple method was developed to form noncovalently linked mimic of the liver extracellular matrices. Collagen/chitosan mixtures in various proportions (i.e., 1:0, 3:2, 1:1, 2:3, and 0:1 v/v) were lyophilized or evaporated to form sponges or flat films before they were gelled using an aqueous 25% ammonia solution. The porosities of the obtained sponges were above 90% with various pore sizes. The highest mechanical strength (1.9+/-0.7 MPa) and the lowest degradation time (65+/-1.7 days) were achieved by the collagen/chitosan (1:1) matrices. Hepatocytes cultured on the collagen/chitosan (1:1) matrices exhibited relatively high glutamate-oxaloacetate transaminase and glucose secretion functions 25 days post-seeding. Nuclues of the hepatocytes were more elongated and arranged in certain directions on the 1:1 matrices. The cytocompatibility and enhanced biostability of our new ammonia-treated collagen/chitosan matrices suggest that they could be used as scaffolds for liver tissue engineering.

Amines↗

PubMed2005

Preparation and characterization of a collagen/chitosan/heparin matrix for an implantable bioartificial liver.

A new type of collagen/chitosan/heparin matrix, fabricated by gelation of collagen/ chitosan with heparin sodium containing ammonia, was produced to construct livers by tissue engineering and regenerative engineering. The obtained collagen/chitosan/heparin matrix was found to be highly porous, swelled rapidly in PBS solution and was stable in vitro for at least 60 days in collagenase/lysozyme containing buffered aqueous solution (PBS, pH 7.4) at 37 degrees C. The collagen/chitosan/heparin matrix resulted in a superior blood compatibility compared to the ammonia-treated collagen and collagen/chitosan matrices. The morphology and behavior of the cells on the collagen/chitosan/heparin membrane were found to be similar to those on the collagen membrane but different from those on the collagen/chitosan membrane. Hepatocytes cultured on the collagen/chitosan/heparin matrices exhibited highest urea and triglyceride secretion functions 25 days post seeding. These results suggest that this collagen/chitosan/heparin matrix is a potential candidate for liver tissue engineering.

Animals↗

PubMed2002

[Rapid manufacturing of degradable porous polymer bone scaffold].

Making bone scaffold through tissue engineering method presents a new choice for both the patients and the doctors of orthopaedics. The biodegradable polymer PLA is chosen to make porous fundus scaffold jetting through special designed nozzle on multi-functional rapid prototyping machine controlled by computer according to the CT data CAD model. The scaffold is then chemically aggregated to compound with collagen-hydroxyapatite, and the ideal bone repair material is obtained. Animal experiment has indicated the correctness of this conclusion.

Absorbable Implants↗