AT-CuAAC Synthesis of Mechanically Interlocked Oligonucleotides

We present a simple strategy for the synthesis of main chain oligonucleotide rotaxanes with precise control over the position of the macrocycle. The novel DNA-based rotaxanes were analyzed to assess the effect of the mechanical bond on their properties.

Increased duplex stabilization in porphyrin-LNA zipper arrays with structure dependent exciton coupling

Porphyrins were attached to LNA uridine building blocks via rigid 5-acetylene or more flexible propargyl-amide linkers and incorporated into DNA strands. The systems show a greatly increased thermodynamic stability when using as little as three porphyrins in a zipper arrangement. Thermodynamic analysis reveals clustering of the strands into more ordered duplexes with both greater negative ΔΔS and ΔΔH values, and less ordered duplexes with small positive ΔΔS differences, depending on the combination of linkers used. The exciton coupling between the porphyrins is dependent on the flanking DNA sequence in the single stranded form, and on the nature of the linker between the nucleobase and the porphyrin in the double stranded form; it is, however, also strongly influenced by intermolecular interactions. This system is suitable for the formation of stable helical chromophore arrays with sequence and structure dependent exciton coupling.

A highly sensitive electrochemical genosensor based on Co-porphyrin-labelled DNA

Cobalt-porphyrin-modified DNA was used to design an electrochemical genosensor which is able to detect a minimum of 1000 DNA molecules.

Regulatory issues relating to therapies for periodontal regeneration

The Food and Drug Administration (FDA) has regulated medical devices since May 1976, when the Medical Device Amendments were enacted. The clinical trial requirements for the marketing of periodontal regeneration devices have been dependent, in part, on the degree of their similarity to devices marketed prior to the legislative enactment date in terms of materials, indication statements, and labeling claims. Nonresorbable barriers were allowed to be marketed based on their equivalence to devices marketed prior to the enactment date based on biocompatability and clinical trial data under the premarket notification requirements section of the law. Bone filling materials such as hydroxyapatite were first marketed based on the finding of equivalence to predicate devices. Newer technologies such as bioabsorbable barriers have also been reviewed under the premarket notification provisions of the law, but manufacturers have been required to provide more extensive safety and effectiveness data to establish equivalence to pre-Amendments devices. Data to answer questions related to the potential toxicity of breakdown products, period of absorption, and ultimate clinical effectiveness needed to be answered prior to marketing. New devices that incorporate technologies that are not substantially equivalent to predicate devices must proceed through the premarket approval route to marketing. For new devices considered a potential significant risk to the patient population, clinical trials are conducted via the investigational device exemption (IDE) requirements that specify the means by which trials will proceed in order to protect the rights of patients. New devices of organic origin, such as bone morphogenic protein, have followed the premarket approval route with IDE requirements instituted as a condition for their path to the marketplace. Issues associated with immediate and long-term contact including potential toxicity, tumorigenicity, and sensitization need to be addressed with appropriate animal models.