Highly compressible hydrogel reinforced with cellulose nanocrystals for ultrasound scanning via microwave-assisted synthesis

Abstract

In this study, a rapid fabrication method was developed to prepare hydrogel structures with high mechanical strength and low attenuation coe cient for ultrasound scanning. Poly acrylic acid (PAA) hydrogel was rst prepared via a free radical polymerization approach. To shorten the process time (~ 30 minutes in water bath), microwave heating was applied to facilitate the reaction and reduce the reaction time down to 80 seconds. The produced hydrogels showed excellent elasticity but had a low compressive strength of 100 kPa. To further enhance the mechanical strengths of PAA hydrogels, cellulosenanocrystals (CNCs) were added to the precursor solution. After the microwave assisted crosslinking process, the compressive strength of the hydrogel increased to 350 kPa. Moreover, the ultimate compressive strain was enhanced from 60% to 80% with great recoverability. The PAA/CNC hydrogel has a great ultrasound trnansimission for high-quality ultrasound images comparable to conventional liquid hydrogels. To demonstrate the feasibility of the PAA/CNC hydrogel in ultrasonic medical applications, a customized ultrasound probe coat was created with a 3D printed mold and practically used in the ultrasound scanning process.

Liquid Metal Nanoparticles Physically Hybridized with Cellulose Nanocrystals Initiate and Toughen Hydrogels with Piezoionic Properties

“…Yet, we found that adding 0.5 wt % CNC to the hydrogel without LM did not cause a meaningful change in mechanical properties (Figure S15), even though there are literature examples in which CNC can toughen the PAA gels. 54,55 The lack of meaningful change might be due to the lower aspect ratio of CNCs (L/D around 9, according to TEM images) used in this work. We selected CNCs with a lower aspect ratio to avoid aggregation and improve coating the LM.…”

Preparation of Nanocellulose Whisker/Polyacrylamide/Xanthan Gum Double Network Conductive Hydrogels

“…Pi et al, prepared CNC/Mxene PVA/PAAM hydrogels with desirable strain-sensitive conductivity and good thermal resistivity [33]. Cheng et al used microwave incorporation to prepare PAA/CNC hydrogels with good biocompatibility and high transmission to ultrasound [34]. Peng et al, cross-linked hydrogels with a high swelling rate using quaternized membranous cellulose nanocrystals (Q-TCNCs), carboxymethylcellulose (CMC), and epichlorohydrin (EPI), and their mechanical properties and swelling rate could be controlled by adjusting the Q-TCNCs content [35].…”