Antimicrobial loading into and release from poly(ethylene glycol)/poly(acrylic acid) semi‐interpenetrating hydrogels

Abstract

Electrostatic interactions within a semi‐interpenetrating network (semi‐IPN) gel can control the postsynthesis loading, long‐term retention, and subsequent release of small‐molecule cationic antibiotics. Here, electrostatic charge is introduced into an otherwise neutral gel [poly(ethylene glycol) (PEG)] by physically entrapping high‐molecular‐weight poly(acrylic acid) (PAA). The network structure is characterized by small‐angle neutron scattering. PEG/PAA semi‐IPN gels absorb over 40 times more antibiotic than PAA‐free PEG gels. Subsequent soaking in physiological buffer (pH 7.4; 0.15 M NaCl) releases the loaded antibiotics for periods as long as 30 days. The loaded gels elute antibiotics with diffusivities of 4.46 × 10−8 cm2/s (amikacin) and 2.08 × 10−8 cm2/s (colistin), which are two orders of magnitude less than those in pure PEG gels where diffusion is controlled purely by gel tortuosity. The release and hindered diffusion can be understood based on the partial shielding of the charged groups within the loaded gel, and they have a significant effect on the antimicrobial properties of these gels. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 64–72

Dynamic photopolymerization produces complex microstructures on hydrogels in a moldless approach to generate a 3D intestinal tissue model

“…We copolymerized PEGDA with A c c e p t e d M a n u s c r i p t different amounts of AA ranging from 0 to 1.2% w/v. The incorporation of AA was assessed by the presence of a strong absorbance peak at 1576 cm -1 in the FTIR spectra, which is attributed to the asymmetric vibration of carboxyl groups, ( Figure S4) [42]. Factors such as viscosity of the solution or the presence of oxygen may affect the kinetics of the reaction and the polymerization rate.…”

Counterion Exchange in Peptide-Complexed Core–Shell Microgels

“…In these expressions, C n is the characteristic ratio (6.7), 39−42 M c is the average molecular weight between cross-links, M r is the molecular weight of the repeat unit (72 g/mol), M n is taken as 75000 g/mol, 43,44 l is the bond length along the polymer chain (0.154 nm), χ is the Flory−Huggins interaction parameter between the polymer and the solvent (0.5), 40,43,45 v ̅ 1 is the molar volume of the solvent (18.1 cm 3 /mol), M is the specific volume of the polymer in the amorphous state (0.951 cm 3 /g), and v 2,r is the polymer volume fraction immediately after synthesis (0.20). The water contents (Table 2) can be converted to polymer volume fraction in the fully swollen state v 2,s by eq 6, assuming a water density, ρ s , and polymer density, ρ p , of 1.00 and 1.05 g/cm 3 , respectively. This model estimates the mesh size of an as-synthesized microgel as 39 nm and of an L5-complexed microgel core as 31 nm.…”

Strategy to construct polyzwitterionic hydrogel coating with antifouling, drag-reducing and weak swelling performance

“…PAA hydrogel coating, as a typical anionic polyelectrolyte, exhibits a relatively larger volume in low concentration of saline solution due to electrostatic shielding effect. 53 When the concentration of NaCl solution is higher than a certain value, the swollen ratio decreases with concentration, that is, volume collapse occurs and causes shrinkage. The swelling degree of PAA hydrogel in ASW is only 0.3.…”