Short Tandem Repeat DNA Profiling Using Perylene-Oligonucleotide Fluorescence Assay.

We report an amplification-free genotyping method to determine the number of human short tandem repeats (STRs). DNA-based STR profiling is a robust method for genetic identification purposes such as forensics and biobanking and for identifying specific molecular subtypes of cancer. STR detection requires polymerase amplification, which introduces errors that obscure the correct genotype. We developed a new method that requires no polymerase. First, we synthesized perylene-nucleoside reagents and incorporated them into oligonucleotide probes that recognize five common human STRs. Using these probes and a bead-based hybridization approach, accurate STR detection was achieved in only 1.5 h, including DNA preparation steps, with up to a 1000-fold target DNA enrichment. This method was comparable to PCR-based assays. Using standard fluorometry, the limit of detection was 2.00 ± 0.07 pM for a given target. We used this assay to accurately identify STRs from 50 human subjects, achieving >98% consensus with sequencing data for STR genotyping.

Dynamic covalent crosslinked hyaluronic acid hydrogels and nanomaterials for biomedical applications.

Hyaluronic acid (HA), one of the main components of the extracellular matrix (ECM), is extensively used in the design of hydrogels and nanoparticles for different biomedical applications due to its critical role in vivo, degradability by endogenous enzymes, and absence of immunogenicity. HA-based hydrogels and nanoparticles have been developed by utilizing different crosslinking chemistries. The development of such crosslinking chemistries indicates that even subtle differences in the structure of reactive groups or the procedure of crosslinking may have a profound impact on the intended mechanical, physical and biological outcomes. There are widespread examples of modified HA polymers that can form either covalently or physically crosslinked biomaterials. More recently, studies have been focused on dynamic covalent crosslinked HA-based biomaterials since these types of crosslinking allow the preparation of dynamic structures with the ability to form in situ, be injectable, and have self-healing properties. In this review, HA-based hydrogels and nanomaterials that are crosslinked by dynamic-covalent coupling (DCC) chemistry have been critically assessed.