Sodium Deoxycholate Hydrogels: Effects of Modifications on Gelation, Drug Release, and Nanotemplating

• Published in: The journal of physical chemistry. B 2015-07, Vol.119 (27), p.8651-8659
• Main Authors: McNeel, Kelsey E, Das, Susmita, Siraj, Noureen, Negulescu, Ioan I, Warner, Isiah M
• Format: Article
• Language: English
• Subjects: Anisotropy; Deoxycholic Acid - chemistry; Drug Delivery Systems - instrumentation; Drug Liberation; Hydrogels - chemistry; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Ions - chemistry; Materials Testing; Mechanical Phenomena; Microscopy, Electron, Transmission; Microscopy, Polarization; Nanoparticles - chemistry; Rheology; Transition Temperature; Tromethamine - chemistry; X-Ray Diffraction
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/acs.jpcb.5b00411

In the present study, sodium deoxycholate (NaDC) was used to produce gelation of tris­(hydroxymethyl)­amino-methane (TRIS) solutions above, below, and near the pK a of NaDC, respectively, which yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol–gel temperature, crystallinity, and mechanical strength. Several formulations yielded a unique rheological finding of two stable regions of elastic modulus. The release of a small molecule has been investigated under different hydrogel conditions and at variable shear rate, suggesting utility as a drug-delivery vehicle. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), specifically cyanine-based NIR dyes, were templated within the hydrogel network for potential applications in tissue imaging. These nanoGUMBOS were found to be size-tunable, although material-dependent. Further understanding of NaDC/TRIS gelation has broadened the tunability and multidimensional applications of these tailored hydrogel systems.