Scientists recently published a study in "Nature Communications" saying that a team from Rice University and the University of Houston in the United States achieved directional fiber alignment during the production of bacterial cellulose through a simple and scalable process, producing a bio-based material with both high strength and versatility, which is considered promising to replace some traditional plastics.
Plastic pollution has long been a global problem. Common synthetic polymers decompose into microplastics in the environment and release harmful chemicals such as bisphenol A (BPA), phthalates, and some carcinogens. To this end, the research team headed by Mohammad Maqsood Rahman turned their attention to the natural biopolymer-bacterial cellulose, which is rich in sources, high in purity and biodegradable.
Studies have pointed out that bacterial cellulose itself is composed of nanoscale fibers and has excellent mechanical foundation. However, due to the disordered direction of the fibers during the natural growth process, the overall performance has not been fully exerted. In addition, when other nanofillers are introduced into this three-dimensional dense network, they also face dispersion and penetration difficulties, which limits the expansion of the material's functions. To solve the above problems, the team designed a rotating bioreactor that uses fluid movement to guide the movement direction of cellulose-producing bacteria so that they are "forced to line up" during the growth process, thereby achieving directional fiber growth.
M.A.S.R. Saadi, the first author of the paper and a doctoral student at Rice University, said that this method is equivalent to "training a disciplined team of bacteria", allowing the originally random swimming bacteria to move in a set direction, and directionally produce cellulose in the process. Through this dynamic biosynthesis strategy, the oriented bacterial cellulose sheets produced by the researchers have a tensile strength of approximately 436 MPa, which is comparable in strength to some metals and glass. It is also flexible, foldable, transparent, and environmentally friendly.
In further experiments, the team added hexagonal boron nitride nanosheets directly to the bacterial culture nutrient solution, allowing them to be incorporated into the cellulose network in situ during the synthesis process. The tensile strength of this composite material has been increased to a maximum of 553 MPa, and its thermal performance has also been significantly improved. The thermal conductivity is about three times that of the control sample, which helps to dissipate heat quickly. The researchers emphasized that this method provides convenience for the "bottom integration" of multiple nano-additives during the material generation stage, and can tailor mechanical, thermal and other properties according to application requirements.
The team believes that this single-step, bottom-up preparation route has the potential for industrial scale-up. Thanks to the simplification of the process and the wide range of material sources, it is expected to be applied in the fields of packaging, textiles, structural materials, thermal management, green electronic devices, and energy storage in the future. Rahman pointed out that this work demonstrates the power of interdisciplinary research in materials science, biology and nanoengineering, with the ultimate goal of allowing this strong, multifunctional and eco-friendly bacterial cellulose sheet to replace some plastics in various scenarios and reduce environmental damage.
The research team concluded that by solving the long-standing problems of fiber orientation and filler diffusion that have plagued bacterial cellulose, this process opens the door to high-performance engineering materials for this natural biopolymer. They believe that this biodegradable, performance-adjustable bio-based material provides a realistic path to reduce dependence on traditional plastics, and also brings new technological imagination to global plastic pollution control.