Highly tunable bioadhesion and optics of 3D printable PNIPAm/cellulose nanofibrils hydrogels

• Published in: Carbohydrate polymers 2020-04, Vol.234, p.115898-115898, Article 115898
• Main Authors: Sun, Xiaohang, Tyagi, Preeti, Agate, Sachin, McCord, Marian G., Lucia, Lucian A., Pal, Lokendra
• Format: Article
• Language: English
• Subjects: 3D printing; Cellulose nanofibrils (CNFs); Hydrogels; Inverted stereolithography; Poly(N-isopropylacrylamide) (PNIPAm); Stimuli-responsive materials; Switchable bioadhesion; Tunable transparency
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2020.115898

[Display omitted] •Tunable poly(N-Isopropylacrylamide)-cellulose nanofibrils hydrogel films.•Fabrication using inverted SLA 3D printing to provide a new manufacturing platform.•Switchable bio-adhesion to bacteria depending on the CNF content and distribution.•Unique thermo-responsivity and tunable optical performance.•Modulation of LCST (∼ 8 °C reduction) relative to pure PNIPAm hydrogel films. A hybrid poly(N-isopropylacrylamide) (PNIPAm)/cellulose nanofibrils (CNFs) hydrogel composite was fabricated by inverted stereolithography 3D printing to provide a new platform for regulating lower critical solution temperature (LCST) properties and thus tuning optical and bioadhesive properties. The phenomena of interest in the as-printed PNIPAm/CNF hydrogels may be attributed to the fiber-reinforced composite system between crosslinked PNIPAm and CNFs. The optical tunability was found to be correlated to the micro/nano structures of the PNIPAm/CNF hydrogel films. It was found that PNIPAm/CNF hydrogels exhibit switchable bioadhesivity to bacteria in response to CNF distribution in the hydrogels. After 2.0 wt% CNF was incorporated, it was found that a remarkable 8°C reduction of the LCST was achieved relative to PNIPAm hydrogel crosslinked by TEGDMA without CNF. The prepared PNIPAm/CNF hydrogels possessed highly reversible optical, bioadhesion, and thermal performance, making them suitable to be used as durable temperature-sensitive sensors and functional biomedical devices.