生物化学技术

Poly (α-hydroxyacids) were found to be bioabsorble and biocompatible in the 1960s (1,2). They are the most widely known, studied and used bioabsorbable synthetic polymers in medicine. Polyglycolide (PGA) and poly-l-lactide (PLLA) homopolymers and their copolymers (PLGA), as well as pol ...

Hyaluronan (HA) is a naturally occurring, negatively charged high mol-wt glycosaminoglycan (GAG), that is composed of repeated disaccharide units of D-glucuronic acid and N-acetylglucosamine. It is the only GAG that lacks an associated protein moiety and sulfate groups. HA is a highly co ...

Fibrinogen exerts adhesive effects on cultured fibroblasts and other cells. Specifically, fibrin(ogen) and its various lytic fragments (e.g., FPA, FPB, fragments D and E) were shown to be chemotactic to macrophages, human fibroblasts, and endothelial cells (1–3). Thrombin has also been sh ...

Chitin, poly(N-acetylglucosamine) is a structural polysaccharide found in the shell of crustaceans and mollusks and is typically isolated from waste produced in food processing. The procedure for extracting chitin from crustacean shells usually involves decalcification, de ...

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β (TGF-β) superfamily of proteins that have crucial roles in growth and regeneration of skeletal tissues. In particular, recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to ind ...

Alginate is a polysaccharide derived from brown seaweed, which has the unique property of being able to form a gel in the presence of certain divalent cations (e.g., calcium, strontium, or barium). Alginate has been of commercial interest in the food industry since the 1930s, when its properties as an e ...

The ultimate goal of tissue engineering is to replace, repair or enhance the biological function of damaged, absent or dysfunctional elements of a tissue or an organ. Engineered tissues are produced by using cells that are manipulated through their extracellular environment to develop l ...

Bioactive polymeric materials can be constructed via the modification of bioinert polymers with bioactive peptides such as cell-adhesion peptides or growth factors. Such materials can be designed to induce specific biological responses desired in applications such as tissue en ...

Current research in the field of tissue engineering is focused on the development of appropriate strategies for repair and regeneration of biological tissues. Biological tissues consist of cells situated within a complex molecular framework known as the extracellular matrix (ECM) ...

The capacities of RNA for both catalysis and molecular recognition have been appreciated for some time. Recently, a number of studies have shown that these distinct functional classes may be combined to generate multipartite ribozymes in which the catalytic and ligand-binding elemen ...

Here, we describe allosteric ribozymes, which are activated by the addition of a short regulator oligonucleotide. The allosteric hammerhead ribozyme, which contains a single-stranded loop instead of stem II, exhibited minimal cleavage of the target RNA; however, it becomes active by the ...

We have succeeded in constructing an effective system for the expression of ribozymes under the control of a human tRNAVal promoter, which ensures a high level of production of ribozymes in vivo. The engineered tRNAVal-driven ribozymes, based on computer-predicted secondary structu ...

A major obstacle to achieving constitutive ribozyme expression in cells is that expression or elimination of the target gene may provide either a growth advantage or disadvantage to the cells that express ribozyme. Many approaches have been used to overcome this problem, mostly based on the e ...

The U1snRNA/ribozyme/antisense construct (designated U1/ribozyme) is a chimeric transgene that has proven to be very useful for inhibiting the expression of targeted genes in vitro and in vivo. It consists of a combination of hammerhead ribozyme flanked by target-specific antisense ...

Hammerhead ribozymes are small, catalytic RNAs that can be designed to effectively inhibit gene expression in an allele-specific manner. It is the high level of sequence discrimination, coupled with the minimal cleavage-site requirements of hammerhead ribozymes, that makes these c ...

Hybrid ribozymes that couple the cleavage activity of hammerhead ribozymes with the unwinding activity of RNA helicases are powerful tools in the study of cell genetics and pharmaceutical drug development. They are useful for targeting a specific gene as well as screening functional ge ...

Ribozymes have potential as therapeutic agents and in functional studies of genes of interest. The activities of ribozymes in vivo depend on the accessibility of ribozymes to a cleavage site in the target RNA. At present, the selection of a target site for ribozymes is often based on a computer-aided ...

Ribozymes are small and versatile nucleic acids that can cleave RNAs at specific sites. These molecules have great potential to be used as effective gene-therapeutic agents. However, because of the limitation for cleavable sequences within the target mRNA, in some cases conventional ri ...

The 10–23 DNAzyme is capable of cleaving RNA with high sequence specificity at sites that contain purine-pyrimidine (R-Y) junctions. Although they are abundant in mRNA, many of these potentially cleavable junctions are protected from DNAzyme activity by secondary structure. To optim ...

The sequence specificity of the “10–23” RNA-cleaving DNA enzyme can be utilized to discriminate between subtle differences in nucleic acid sequence. We examined this potential by comparing the cleavage activity of DNAzymes that target sequences derived from a relatively conserved s ...