title: Self-degrading, MRI-detectable hydrogel sensors with picomolar target sensitivity.
abstract: Nanostructured hydrogels have been developed as synthetic tissues and scaffolds for cell and drug delivery, and as guides for tissue regeneration. A fundamental problem in the development of synthetic hydrogels is that implanted gel structure is difficult to monitor noninvasively. This work demonstrates that the aggregation of magnetic nanoparticles, attached to specific macromolecules in biological and synthetic hydrogels, can be controlled to detect changes in gel macromolecular structure with MRI. It is further shown that the gels can be made to self-degrade when they come into contact with a target molecule in as low as pM concentrations. The sensitivity of the gels to the target is finely controlled using an embedded zymogen cascade amplifier. These "MRI reporter gels" may serve as smart, responsive polymer implants, as tissue scaffolds to deliver drugs, or to detect specific pathogens in vivo.
authors.affiliation: School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Colomb
authors.forename: Katherine
authors.initials: K
authors.lastname: Louie
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Massia
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Bennett
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D016503:Drug Delivery Systems; D004765:Enteropeptidase / Q000737:chemistry; D004792:Enzyme Precursors / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D016014:Linear Models; D046911:Macromolecular Substances / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011509:Proteoglycans / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering; D014362:Trypsinogen / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D004792:Enzyme Precursors; D005290:Ferric Compounds; D020100:Hydrogels; D046911:Macromolecular Substances; D011108:Polymers; D011509:Proteoglycans; C000499:ferric oxide; D014362:Trypsinogen; D004765:Enteropeptidase