# A Review of Properties of Nanocellulose, Its Synthesis, and Potential in Biomedical Applications
## 6 Biomedical Applications of Nanocellulose  
### Replacement of Blood Vessels  
Heart bypass surgery, conducted to deliver blood to the cardiac tissue with an appropriate replacement of blood vessels, is among the most popular therapies for cardiovascular illness. Nanocellulose (particularly BNC) can be developed as a medium for synthetic conduits that can substitute moderate or larger vascular grafts (Figure 4a) because of its biocompatibility and mechanical characteristics. [PERSON]'s team at the University of  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Composites Combined with** & & & **Accepted Chemical** & **Significant Outcomes** & **Ref.** \\
**Cellulose and Natural Fibers** & & & & \\ \hline \multirow{3}{*}{Cellulose nanofibers (CNFs)} & Epoxy/Diglyceryl Ether of Bisphenol (DCEBA) & & & The presence of CNFs & \\  & Epoxy/Diglyceryl Ether & & significantly enhances the nanocomposites’ storage, thermal, and loss modulus. & & [151] \\  & of Bisphenol (DCEBA) & & & \\  & & & & \\ \hline \multirow{3}{*}{Cellulose nanofibers, Bacterial nanocellulose (CNFs/BNC)} & \multirow{3}{*}{Polyvinyl Alcohol (PVA)} & \multirow{3}{*}{Acetylation} & CNFs have enhanced mechanical characteristics and remarkably visible light transmission. & & \\  & & & & \\ \hline Microcrystalline cellulose (MCC) & \multirow{3}{*}{Polyvinyl alcohol (PVA)} & NaOH/Urea & PVA-based MCC has & \\  & & & improved fracture toughness. & \\ \hline Lignin-coated cellulose nanocrystals (L-CNCs) & \multirow{3}{*}{Polylactic acid (PLA)} & \multirow{3}{*}{-} & Thermo-mechanical characteristics are enhanced. & & \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Sugarcane Bagsase and \\ cellulose nanocrystals (SCB/CNCs) \\ \end{tabular} } & \multirow{3}{*}{k-carrageenan} & \multirow{3}{*}{Alkali} & The incorporation of CNCs & \\  & & & increased the mechanical strength. & \\ \hline \multirow{3}{*}{Cellulose nanoffibrils} & \multirow{3}{*}{-} & & The cellulose nanoffibrils & \\  & & & increased the compression & \\ \cline{1-1}  & & & resistance to deformation. & \\ \hline \hline \end{tabular}
\end{table}
Table 1: The positive results of the nanocellulose-based composites.  
Jena in Germany was the first to investigate and utilize engineered circulatory substitutes made from bacterial nanocellulose nanomaterials [162; 163; 164]. They have presented a therapeutic product called Bacterial Synthesized Cellulose, also known as BASYC. The BASYC has shown excellent moisture retention, good mechanical strength in wet conditions, and reduced internal tube surface roughness. BASYC from the bacterial nanocellulose has been effectively employed as a synthetic blood vessel in pigs and rats for microsurgery [165; 166].  
Unlike the BNC biosynthetic method, manually constructing tubes from CNF and CNC is challenging. As a result, a matrix material is frequently used in developing CNF and CNC-dependent blood vessel transplants. [PERSON] et al. described the manufacture of CNC-based (fibrin/CNC) biocomposites for small-sized vascular graft replacement. CNC was covalently bonded onto a fibrin matrix, providing nano-reinforcement concerning the elasticity and strength of the composite material [167].  
Biopolymers made of polyurethane and CNF are reported as promising materials for blood vessel replacement. The inclusion of the CNF in polyurethane increased the material's elasticity and mechanical and physical characteristics. In an adult male patient suffering from multiple endocrine neoplasia type 2B (MEN 2B), polyurethane/CNF biomaterials with 0.7-1.0 mm wall thickness were used as vascular prosthesis between the right carotid artery and the brachiocephalic trunk. Figure 4b shows the vascular prosthesis implants of polyurethane and CNF to treat MEN 2B. Admittedly, no other diagnostic and therapeutic effects of this polyurethane/CNF biomaterial have been recorded [7].