Biocompatible Hydroxylated Boron Nitride Nanosheets/Poly(vinyl alcohol) Interpenetrating Hydrogels with Enhanced Mechanical and Thermal Responses

Abstract

Poly(vinyl alcohol) (PVA) hydrogels with tissue-like viscoelasticity, excellent biocompatibility, and high hydrophilicity have been considered as promising cartilage replacement materials. However, lack of sufficient mechanical properties is a critical barrier to their use as load-bearing cartilage substitutes. Herein, we report hydroxylated boron nitride nanosheets (OH-BNNS)/PVA interpenetrating hydrogels by cyclically freezing/thawing the aqueous mixture of PVA and highly hydrophilic OH-BNNS (up to 0.6 mg/mL, two times the highest reported so far). Encouragingly, the resulting OH-BNNS/PVA hydrogels exhibit controllable reinforcements in both mechanical and thermal responses by simply varying the OH-BNNS contents. Impressive 45, 43, and 63% increases in compressive, tensile strengths and Young's modulus, respectively, can be obtained even with only 0.12 wt% (OH-BNNS:PVA) OH-BNNS addition. Meanwhile, exciting improvements in the thermal diffusivity (15%) and conductivity (5%) can also be successfully achieved. These enhancements are attributed to the synergistic effect of intrinsic superior properties of the as-prepared OH-BNNS and strong hydrogen bonding interactions between the OH-BNNS and PVA chains. In addition, excellent cytocompatibility of the composite hydrogels was verified by cell proliferation and live/dead viability assays. These biocompatible OH-BNNS/PVA hydrogels are promising in addressing the mechanical failure and locally overheating issues as cartilage substitutes and may also have broad utility for biomedical applications, such as drug delivery, tissue engineering, biosensors, and actuators.

Customization of Conductive Elastomer Based on PVA/PEI for Stretchable Sensors

“…Representative fluorescence images are shown in Figure a and Figure S6 (Supporting Information). After culture for 1 d, similar live cell (red) densities were observed for all the groups, indicating none cytotoxicity of the samples . Later, cells continuously proliferated and spread homogeneously until full coverage after 3 d of culture, indicating good cell proliferation of the elastomer treated cells.…”

Carbon Nanotube Reinforced Supramolecular Hydrogels for Bioapplications

“…The co‐incubation of cells with hydrogels was done for 24 h and 48 h, showing that HeLa cell viability was maintained at high levels compared to the untreated controls (Figure S4, Supporting Information). However, it should be noted that in this test hydrogel disks might have had exerted external pressure on cell monolayers, thus slightly affecting cell viability …”

Multifunctional Nanoengineered Hydrogels Consisting of Black Phosphorus Nanosheets Upregulate Bone Formation

“…For example, Xavier et al recently reported that the addition of exfoliated ultrathin nanoclays led to increased stiffness and promoted osteogenic differentiation of hybrid hydrogels compared to pristine collagen‐based hydrogels . In addition, biocompatible hydroxylated boron nitride nanosheet‐reinforced polyvinyl alcohol (PVA) hydrogels were shown to be an attractive candidate for cartilage replacement . These results suggested that nanoengineered (NE) hydrogel‐based 2D nanomaterials acting as bioactive substitutes may have great potential for load‐bearing tissue applications.…”