## 3 Conclusions and Outlooks  
In summary, biomass materials have exhibited great potential for the synthesis of functional nanoscale and microscale materials via structural and functional regulation. Biomass can be used as good additives for the reinforcement of polymer materials, the biomimetic synthesis of various nanoparticles, and hybridization with other nanomaterials--all of which enhance the physical, chemical, and biological properties and functions of biomass materials as well as extend their applications. In addition, with the help of nanotechnology, biomass materials can be constructed into 1D, 2D, and 3D structures by various nanotechnologies, such as self-assembly, electrospinning, 3D printing, and others. With the high energy-savingand sustainability demands of modern society, the use of biomass materials in energy science, environmental science, and human healthcare is sure to attract more scientific attention in the future.  
To promote the development of biomass materials, the author would like to demonstrate several potential research topics here in this promising field. Firstly, more efforts should be carried out to produce biomass nanomaterials (such as nanofibers, nanorods, and nanosheets) with high dispersity and solubility through the chemical, physical, and biological modification of biomass molecules. Subsequently, the combination of regulated biomass materials with other nanoscale building blocks, such as polymers, nanoparticles, nanotubes, and 2D materials, can be easily performed. Secondly, it is suggested that biomass-based films and membranes be fabricated using the self-assembly and vacuum filtering techniques. In these cases, the doping of catalytic nanoparticles (such as TiO\({}_{2}\), MnO\({}_{2}\), and others) and 2D graphene/MXene nanosheets into biomass films/membranes could greatly improve the performance of materials and extend their application in dye degradation, desalination, ionic adsorption and removal, and molecule separation. Thirdly, it is beneficial to further the biomimetic synthesis of functional nanomaterials based on biomass material properties, given that biomimetic mineralization is one of the unique abilities of biomass molecules. Biomimetic biomass materials have high bioactivity, good biodegradation, and satisfactory biocompatibility, and they could be widely utilized for the construction of bioactive hydrogels for wound healing, nerve regeneration, bone repair, and antimicrobial devices. Fourthly, producing hierarchical 3D biomass materials via advanced techniques, such as electrospinning and 3D printing, is a compelling area of research. The structural regulation of biomass materials can increase the mechanical properties of hybrid materials, and their hierarchical structures can mimic the complex structure of some organisms in nature, such as seashells, sharkskin, corals, and others, presenting high mechanical strength and other unique abilities as well, such as self-cleaning and antifouling. Finally, it is necessary to perform sustainability analyses of the biomass materials under study, and these can be affected by many factors, such as biomass type, societal factors, policy-related factors, economic factors, and others. However, readers are suggested to refer to two potential methods for the evaluation of the sustainability of biomass materials: ranking efficiency product (REP) [24] and sustainability footprint (SF) analysis [25].  
Author [PERSON] was employed by the company New Dongyue Group Co., Ltd. The author declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.