In situ biomineralization reinforcing anisotropic nanocellulose scaffolds for guiding the differentiation of bone marrow-derived mesenchymal stem cells.

Nanocellulose (NC) is a promising biopolymer for various biomedical applications owing to its biocompatibility and low toxicity. However, it faces challenges in tissue engineering (TE) applications due to the inconsistency of the microenvironment within the NC-based scaffolds with target tissues, including anisotropy microstructure and biomechanics. To address this challenge, a facile swelling-induced nanofiber alignment and a novel in situ biomineralization reinforcement strategies were developed for the preparation of NC-based scaffolds with tunable anisotropic structure and mechanical strength for guiding the differentiation of bone marrow-derived mesenchymal stem cells for potential TE application. The bacterial cellulose (BC) and cellulose nanofibrils (CNFs) based scaffolds with tunable swelling anisotropic index in the range of 10-100 could be prepared by controlling the swelling medium. The in situ biomineralization efficiently reinforced the scaffolds with 2-4 times and 10-20 times modulus increasement for BC and CNFs, respectively. The scaffolds with higher mechanical strength were superior in supporting cell growth and proliferation, suggesting the potential application in TE application. This work demonstrated the feasibility of the proposed strategy in the preparation of scaffolds with mechanical anisotropy to induce cells-directed differentiation for TE applications.

Fabrication of bio-inspired anisotropic structures from biopolymers for biomedical applications: A review.

The anisotropic features play indispensable roles in regulating various life activities in different organisms. Increasing efforts have been made to learn and mimic various tissues' intrinsic anisotropic structure or functionality for broad applications in different areas, especially in biomedicine and pharmacy. This paper discusses the strategies for fabricating biomaterials using biopolymers for biomedical applications with the case study analysis. Biopolymers, including different polysaccharides, proteins, and their derivates, that have been confirmed with sound biocompatibility for different biomedical applications are summarized, with a special focus on nanocellulose. Advanced analytical techniques for understanding and characterizing the biopolymer-based anisotropic structures for various biomedical applications are also summarized. Challenges still exist in precisely constructing biopolymers-based biomaterials with anisotropic structures from molecular to macroscopic levels and fitting the dynamic processes in native tissue. It is foreseeable that with the advancement of biopolymers' molecular functionalization, biopolymer building block orientation manipulation strategies, and structural characterization techniques, developing anisotropic biopolymer-based biomaterials for different biomedical applications would significantly contribute to a friendly disease-curing and healthcare experience.

Functionalization of nanocellulose applied with biological molecules for biomedical application: A review.

Nanocellulose has great potential in the biomedical field due to its biocompatibility, large specific surface area, and customizable surface chemistry. However, due to the bioinert nature and mismatch of the mechanical strength, nanocellulose itself has no cell adhesion ability and cannot directly promote cell growth and reproduction. Recently, surface functionalization of nanocellulose has been reported as an indispensable strategy for improving its bioactivities or other physic-chemical properties. In this paper, functionalization strategies of nanocellulose based on its inherent hydroxyl, aldehyde, carboxyl, and sulfate group reactions are reviewed. Biomacromolecules, such as peptides, proteins, and DNA that are commonly used in functionalization for different biomedical applications are summarized. Prospects and ongoing challenges of nanocellulose-based biomaterials application, as well as these advanced processing technologies such as additive manufacturing, nanomanufacturing, and bio-manufacturing are also discussed. This review is supposed to serve as a guideline for the development of nanocellulose-based biomaterials in biomedical applications.

Development of Cellulose Nanofibril/Casein-Based 3D Composite Hemostasis Scaffold for Potential Wound-Healing Application.

Excessive bleeding in traumatic hemorrhage is the primary concern for natural wound healing and the main reason for trauma deaths. The three-dimensional (3D) bioprinting of bioinks offers the desired structural complexity vital for hemostasis activity and targeted cell proliferation in rapid and controlled wound healing. However, it is challenging to develop suitable bioinks to fabricate specific 3D scaffolds desirable in wound healing. In this work, a 3D composite scaffold is designed using bioprinting technology and synergistic hemostasis mechanisms of cellulose nanofibrils (TCNFs), chitosan, and casein to control blood loss in traumatic hemorrhage. Bioinks that consist of casein bioconjugated TCNF (with a casein content of 104.5 ± 34.1 mg/g) using the carbodiimide cross-linker chemistry were subjected to bioprinting for customizable 3D scaffold fabrication. Further, the 3D composite scaffolds were in situ cross-linked using a green ionic complexation approach. The covalent conjugation among TCNF, casein, and chitosan was confirmed by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and X-ray diffraction (XRD) studies. The in vitro hemostasis activity of the 3D composite scaffold was analyzed by a human thrombin-antithrombin (TAT) assay and adsorption of red blood cells (RBCs) and platelets. The 3D composite scaffold had a better swelling behavior and a faster whole blood clotting rate at each time point than the 3D TCNF scaffold and commercial cellulose-based dressings. The TAT assay demonstrated that the 3D composite scaffold could form a higher content of thrombin (663.29 pg/mL) and stable blood clot compared to a cellulosic pad (580.35 pg/mL), 3D TCNF (457.78 pg/mL), and cellulosic gauze (328.92 pg/mL), which are essential for faster blood coagulation. In addition, the 3D composite scaffold had a lower blood clotting index (23.34%) than the 3D TCNF scaffold (41.93%), suggesting higher efficiencies for RBC entrapping to induce blood clotting. The in vivo cytocompatibility was evaluated by a 3D cell culture study, and results showed that the 3D composite scaffold could promote growth and proliferation of NIH 3T3 fibroblast cells, which is vital for wound healing. Cellulase-based in vitro deconstruction of the 3D composite scaffold showed significant weight loss (80 ± 5%) compared to the lysozyme hydrolysis (22 ± 5%) after 28 days of incubation, suggesting the biodegradation potential of the composite scaffold. In conclusion, this study proposes efficient prospects to develop a 3D composite scaffold from bioprinting of TCNF-based bioinks that can accelerate blood clotting and wound healing, suggesting its potential application in reducing blood loss during traumatic hemorrhage.