A rechargeable anti-thrombotic coating for blood-contacting devices.

Despite the potential of anti-thrombogenic coatings, including heparinized surfaces, to improve the performance of blood-contacting devices, the inevitable deterioration of bioactivity remains an important factor in device failure and related thrombotic complications. As a consequence, the ability to restore the bioactivity of a surface coating after implantation of a blood-contacting device provides a potentially important strategy to enhance its clinical performance. Here, we report the regeneration of a multicomponent anti-thrombogenic coating through use of an evolved sortase A to mediate reversible transpeptidation.

In situ regeneration of bioactive coatings enabled by an evolved Staphylococcus aureus sortase A.

Surface immobilization of bioactive molecules is a central paradigm in the design of implantable devices and biosensors with improved clinical performance capabilities. However, in vivo degradation or denaturation of surface constituents often limits the long-term performance of bioactive films. Here we demonstrate the capacity to repeatedly regenerate a covalently immobilized monomolecular thin film of bioactive molecules through a two-step stripping and recharging cycle.

Reprogramming the specificity of sortase enzymes.

Staphylococcus aureus sortase A catalyzes the transpeptidation of an LPXTG peptide acceptor and a glycine-linked peptide donor and has proven to be a powerful tool for site-specific protein modification. The substrate specificity of sortase A is stringent, limiting its broader utility. Here we report the laboratory evolution of two orthogonal sortase A variants that recognize each of two altered substrates, LAXTG and LPXSG, with high activity and specificity.

Electrospun catechol-modified poly(ethyleneglycol) nanofibrous mesh for anti-fouling properties.

Electrospun nanofibrous mesh composed of catechol-conjugated 8-arm PEG (8cPEGa) and thiolated PLGA (PLGA-SH) was prepared with various blending ratios of PLGA-SH and 8cPEGa. Cross-linking between the two polymers via catechol-thiol reactions and catechol-catechol conjugation was performed by brief soaking with sodium periodate solution. The chemical conjugation of PLGA-SH and 8cPEGa in the nanofibrous mesh was confirmed by the spectral differences of the Raman spectra and changes in the thermal properties.

Antifouling glycocalyx-mimetic peptoids.

The glycocalyx of the cell is composed of highly hydrated saccharidic groups conjugated to protein and lipid cores. Although components of the glycocalyx are important in cell-cell interactions and other specific biological recognition events, a fundamental role of the glycocalyx is the inhibition of nonspecific interactions at the cell surface. Inspired by glycoproteins present in the glycocalyx, we describe a new class of synthetic antifouling polymer composed of saccharide containing N-substituted polypeptide (glycopeptoid).

Oligonucleotide chip for the diagnosis of HNF-1 alpha mutations.

Mutations in HNF-1 alpha cause maturity-onset diabetes of the young (MODY) type 3, which is the most prevalent MODY subtype in most countries. In the present study, we investigated an oligonucleotide microchip for the detection of the known HNF-1 alpha mutations. We first optimized the coupling chemistries for covalent immobilization of allele-specific oligonucleotides on aldehyde (CHO)- and thiocyanate (NCS)-activated glass slides and compared their hybridization efficiencies.