Green Preparation of Durian Rind-Based Cellulose Nanofiber and Its Application in Aerogel.

In this study, a green, highly efficient and low energy consumption preparation method of cellulose nanofiber (CNF) was developed by using agricultural and forestry waste durian rinds as raw materials. The power of ultrasonic treatment was successfully reduced to only 360 W with low molecular weight liquid DMSO. The obtained durian rind-based CNF had a diameter of 8-20 nm and a length of several micrometers. It had good dispersion and stability in water, and could spontaneously cross-link to form hydrogel at room temperature when the concentration was more than 0.5%. The microscopic morphology and compressive properties of CNF aerogels and composite cellulose aerogels prepared from durian rind-based CNF were evaluated. It was found that CNF could effectively prevent the volume shrinkage of aerogel, and the concentration of CNF had a significant effect on the microstructure and mechanical properties of aerogel. The CNF aerogel with 1% CNF exhibited a sheet structure braced by fibers, which had the strongest compression performance. The porosity of CNF aerogels was high to 99%. The compressive strength of the composite cellulose aerogel with durian rind-based CNF was effectively enhanced.

Preparation of Silica Aerogel/Resin Composites and Their Application in Dental Restorative Materials.

As the most advanced aerogel material, silica aerogel has had transformative industrial impacts. However, the use of silica aerogel is currently limited to the field of thermal insulation materials, so it is urgent to expand its application into other fields. In this work, silica aerogel/resin composites were successfully prepared by combining silica aerogel with a resin matrix for dental restoration. The applications of this material in the field of dental restoration, as well as its performance, are discussed in depth. It was demonstrated that, when the ratio of the resin matrix Bis-GMA to TEGDMA was 1:1, and the content of silica aerogel with 50 µm particle size was 12.5%, the composite achieved excellent mechanical properties. The flexural strength of the silica aerogel/resin composite reached 62.9546 MPa, which was more than five times that of the pure resin. Due to the presence of the silica aerogel, the composite also demonstrated outstanding antibacterial capabilities, meeting the demand for antimicrobial properties in dental materials. This work successfully investigated the prospect of using commercially available silica aerogels in dental restorative materials; we provide an easy method for using silica aerogels as dental restorative materials, as well as a reference for their application in the field of biomedical materials.

Study on swelling and drug releasing behaviors of ibuprofen-loaded bimetallic alginate aerogel beads with pH-responsive performance.

Bimetallic alginate aerogel beads were prepared by ionotropic gelation method with Ca2+-Ba2+ bimetallic solution and ibuprofen was loaded as a model drug. The swelling and drug releasing behaviors of the beads, especially the influence of barium, were investigated in artificial gastric and intestinal fluids. The results showed that these beads presented higher encapsulation efficiency due to the special structure of aerogel, and barium was beneficial for the more stable structure and drug releasing behavior. The lower swelling capacity of bimetallic beads was observed than monometallic beads. A rapid high-level releasing of ibuprofen was achieved in artificial intestinal fluid, which was up to 96.9% within 1 h, while ibuprofen releasing was avoided in artificial gastric fluid effectively. The drug releasing mechanism of these beads was explored in detail. In the bimetallic crosslinking system, Ba2+ presented a special effect on alginate beads with more sensitive pH response performance. Thus, these beads had more widely potential as a site-specific delivery system, especially for intestinal therapy.

A 'top modification' strategy for enhancing the ability of a chitosan aerogel to efficiently capture heavy metal ions.

Chitosan is a promising substitute for heavy metal ion adsorbents. However, traditional pure chitosan adsorbents have certain disadvantages that limit their application. In this paper, a 'top modification' strategy was used to enhance the capturing ability of chitosan adsorbents. A chitosan aerogel was prepared via physical crosslinking and then enhanced by immersion in ethylenediamine tetraacetic anhydride solution. Finally, an enhanced chitosan aerogel was obtained, and analyses were used to describe its structure, adsorption properties and mechanism. Results showed that both the porous structure and the combined complexations dramatically improved the capturing ability of the chitosan aerogel for heavy metal ions. The theoretical adsorption capacities of the enhanced aerogel for Cu2+, Pb2+ and Cd2+ reached 108.14, 143.73 and 84.62 mg/g, respectively. Due to their environmental friendliness, good adsorption performance, easy separation and reusability, enhanced aerogels have become viable solutions to removing heavy metal pollutants from aquatic systems.