Biomaterials for Cell-Surface Engineering and Their Efficacy

Effects of Various Cell Surface Engineering Reactions on the Biological Behavior of Mammalian Cells

Cell surface engineering technologies can regulate cell function and behavior by modifying the cell surface. Previous studies have mainly focused on investigating the effects of cell surface engineering reactions and materials on cell activity. However, they do not comprehensively analyze other cellular processes. This study exploits covalent bonding, hydrophobic interactions, and electrostatic interactions to modify the macromolecules succinimide ester-methoxy polyethylene glycol (NHS-mPEG), distearoyl phosphoethanolamine-methoxy polyethylene glycol (DSPE-mPEG), and poly-L-lysine (PLL), respectively, on the cell surface. This work systematically investigates the effects of the three surface engineering reactions on the behavior of human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts, including viability, growth, proliferation, cell cycle, adhesion, and migration. The results reveals that the PLL modification method notably affects cell viability and G2/M arrest and has a short modification duration. However, the DSPE-mPEG and NHS-mPEG modification methods have little effect on cell viability and proliferation but have a prolonged modification duration. Moreover, the DSPE-mPEG modification method highly affects cell adherence. Further, the NHS-mPEG modification method can significantly improve the migration ability of HUVECs by reducing the area of focal adhesions. The findings of this study will contribute to the application of cell surface engineering technology in the biomedical field.

Challenges with Cell-based Therapies for Type 1 Diabetes Mellitus

Type 1 diabetes (T1D) is a chronic, lifelong metabolic disease. It is characterised by the autoimmune-mediated loss of insulin-producing pancreatic β cells in the islets of Langerhans (β-islets), resulting in disrupted glucose homeostasis. Administration of exogenous insulin is the most common management method for T1D, but this requires lifelong reliance on insulin injections and invasive blood glucose monitoring. Replacement therapies with beta cells are being developed as an advanced curative treatment for T1D. Unfortunately, this approach is limited by the lack of donated pancreatic tissue, the difficulties in beta cell isolation and viability maintenance, the longevity of the transplanted cells in vivo, and consequently high costs. Emerging approaches to address these limitations are under intensive investigations, including the production of insulin-producing beta cells from various stem cells, and the development of bioengineered devices including nanotechnologies for improving islet transplantation efficacy without the need for recipients taking toxic anti-rejection drugs. These emerging approaches present promising prospects, while the challenges with the new techniques need to be tackled for ultimately clinical treatment of T1D. This review discussed the benefits and limitations of the cell-based therapies for beta cell replacement as potential curative treatment for T1D, and the applications of bioengineered devices including nanotechnology to overcome the challenges associated with beta cell transplantation.

Strategies for Biomaterial-Based Spinal Cord Injury Repair via the TLR4-NF-κB Signaling Pathway

The repair and motor functional recovery after spinal cord injury (SCI) has remained a clinical challenge. Injury-induced gliosis and inflammation lead to a physical barrier and an extremely inhibitory microenvironment, which in turn hinders the recovery of SCI. TLR4-NF-κB is a classic implant-related innate immunomodulation signaling pathway and part of numerous biomaterial-based treatment strategies for SCI. Numerous experimental studies have demonstrated that the regulation of TLR4-NF-κB signaling pathway plays an important role in the alleviation of inflammatory responses, the modulation of autophagy, apoptosis and ferroptosis, and the enhancement of anti-oxidative effect post-SCI. An increasing number of novel biomaterials have been fabricated as scaffolds and carriers, loaded with phytochemicals and drugs, to inhibit the progression of SCI through regulation of TLR4-NF-κB. This review summarizes the empirical strategies for the recovery after SCI through individual or composite biomaterials that mediate the TLR4-NF-κB signaling pathway.