Influence of ciprofloxacin‐based additives on the hydrolysis of nanofiber polyurethane membranes

Abstract

A degradable polycarbonate urethane (PCNU) and an antimicrobial oligomer (AO) were used to generate anti-infective nanofiber scaffolds through blend electrospinning. The AO consists of two molecules of ciprofloxacin (CF) bound through hydrolysable linkages to triethylene glycol. The membranes were conceived for use as tissue engineering scaffolds for the regeneration of soft tissues for the periodontium, where there would be a need for a local dose of antibiotic to the periodontal space as the scaffold degrades in order to prevent biomaterial-associated infection. Scaffolds were made using AO at 7 and 15% w/w equivalent CF, and compared to scaffolds with 15% w/w CF (with HCl counterion). AO was hydrolyzed and released CF continuously over 28 days, while the 15% w/w CF HCl scaffolds showed a burst release within hours, with no subsequent release in the subsequent 28 day period. Released CF from both the AO and CF HCl scaffolds had a similar minimum inhibitory concentration to that of off-the-shelf CF. Interestingly, the introduction of drug in either form (AO or CF HCl) was found to increase the hydrolytic stability of the electrospun degradable PCNU scaffold matrix itself. The alteration of hydrolysis kinetics was attributed to changes in the hydrogen bonding character and microstructure within the scaffolds, introduced by the presence of CF. This study has revealed that in generating in situ drug release systems, the secondary effects of the added drug on the degradation properties of the polymeric carriers must be considered, particularly for systems that act dually as tissue engineering scaffolds. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1211-1222, 2018.

Antibiofilm and immunomodulatory resorbable nanofibrous filing for dental pulp regenerative procedures

“…These results confirm that the antimicrobial activity against planktonic cells was associated with ciprofloxacin, since although the peptide is present on nanofiber surfaces, it is not released to interact with bacteria in aqueous media. Ciprofloxacin burst release might be related to changes in the hydrogen bonding character and microstructure within the scaffold [ 52 ]. In contrast, chitosan allowed the slow and linear release of AMPs [ 53 ], which might explain low rates of IDR-1002 released from PVA/CS nanofibers.…”

Electrospun Polyurethane–Gelatin Composite: A New Tissue-Engineered Scaffold for Application in Skin Regeneration and Repair of Complex Wounds

“…However, looking at the day 7 spectrum for Gel80–PU20 reveals that the typical gelatin peak near 1630 cm –1 is still present, confirming that when compared with the 3 h degradation rate of Gel100, when gelatin is blended with PU, its degradation rate decreases. This observation is believed to be in part associated with strong secondary interactions via hydrogen bonding, as both these polymers are capable of forming H-bonding. , It is reported that the degree of H-bonding significantly influences the degradation of such polymers. ,,, This is a very important compensation because fast degrading scaffolds lack the ability to perform as effective skin substitutes in vivo, limiting the provisional environment for cell infiltration and proliferation as well as presenting a challenge for the accumulation of new ECM formation. The loss of Gel100’s original structure in comparison with Gel80–PU20 for 7 days in the culture media is shown in Figure k, which confirmed the result of the collagenase degradation experiment.…”

A Biodegradable, Tacrolimus-releasing Nerve Wrap Promotes Peripheral Nerve Regeneration

“…The dry elastic modulus of the nerve wrap exceeds the tensile strength of human peripheral nerves (dashed line) indicating sufficient strength to withstand surgical manipulation and suturing. (H) PCNU has a soft polyol segment and a hard diisocynate/chain extender segment 48 . Thermal properties of vehicle and tacrolimus nerve wraps including glass transition temperature (T g ), segment melt temperatures (T m1 and T m2 ), and segment melt enthalpies (∆H 1 and ∆H 2 ), show similar thermal properties with the encapsulation of tacrolimus at the chosen concentration (5.2 w/w%), indicating stability at ambient and body temperature.…”

“…Polycarbonate urethane (PCNU) was synthesized of hexane diisocyanate (52649, Sigma Aldrich, Missouri, USA), Poly(hexamethylene carbonate) diol (461172, Sigma Aldrich) and butanediol (309443, Sigma Aldrich) in a 3:2:1 ratio as previously described 48 . PCNU was mixed with 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP) (105228, Sigma-Aldrich) to make the polymer solutions for electrospinning, in concentrations of 14 w/v % for the inner core and 20 w/v% for the outer shell.…”