Polyampholyte‐ and nanosilicate‐based soft bionanocomposites with tailorable mechanical and cell adhesion properties

Abstract

Engineered tissues are excellent substitutes for treating organ failure associated with disease, injury, and degeneration. Designing new biomaterials with controlled release profiles, good mechanical properties, and cell adhesion characteristics can be useful for the formation of specific functional tissues. Here, we report the formulation of nanocomposite hydrogels based on carboxylated poly-l-lysine and synthetic clay laponite XLG in which four-arm polyethylene glycol with N-hydroxy succinimide ester (PEG-NHS) was used as the chemical crosslinker. Interestingly, the degradation of this gel could be adjusted from a few days to a few months. Incorporation of laponite XLG resulted in the formation of mechanically tough hydrogels and conferred cytocompatibility. The mechanical properties of the nanocomposite could be modulated by changing the crosslinking density and laponite concentration. The feasibility of using this system for cellular therapies was investigated by evaluating cell adhesion on the nanocomposite surface. Thus, these nanocomposites can serve as scaffolds with tunable mechanical and degradation properties that also provide structural integrity to tissue constructs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1379-1386, 2016.

Clay nanoparticles for regenerative medicine and biomaterial design: A review of clay bioactivity

“…Various factors have been suggested as possible mechanisms behind clay-enhanced cell adhesion and spreading. Indirect enhancement of cell adhesion via the adsorption of cell adhesive proteins such as fibronectin or vitronectin from serum supplemented media is frequently cited and likely to play a role 103,104,112,113 . Interestingly though, even in serum-free media, fibroblast attachment and spreading was observed on PEO/clay surfaces following a clay concentration dependent trend.…”

“…Such divalent ions are essential for the function of integrins, the transmembrane receptors that mediate cell interactions with ECM 116 . It has also been suggested that Mg 2+ ions arising from the dissolution of Laponite could promote cell adhesion 112,117 , however, the concentration of clay dissolution expected in physiological buffers is disputed 118 and the concentration of divalent ions in cell culture media is also unlikely to be limiting.…”

Tunable phase‐separation behavior of thermoresponsive polyampholytes through molecular design

“…Carboxylated poly‐ l ‐lysine (COOH‐PLL) is a polyampholyte and has been reported to possess excellent cryopreservation ability when it contains the amino and carboxyl groups in a suitable ratio (i.e., in amounts of 35 and 65 mol %, respectively) …”

“…27 Carboxylated poly-L-lysine (COOH-PLL) is a polyampholyte and has been reported to possess excellent cryopreservation ability when it contains the amino and carboxyl groups in a suitable ratio (i.e., in amounts of 35 and 65 mol %, respectively). [15][16][17][28][29][30] Here we report that the poly-L-lysine-based polyampholyte COOH-PLL shows thermoresponsiveness at its critical temperature and that its critical temperature can be tuned readily by changing its hydrophobicity and charge ratio via simple molecular design. We had previously reported that COOH-PLL shows high cryoprotectiveness 15 and hence can be used as a cryoprotectant and that it can form hydrogels and thus be used for cell encapsulation in tissue engineering and drug delivery.…”

Polyampholyte Hydrogels in Biomedical Applications

“…However, this study clearly demonstrated the easily tuned mechanical properties of polyampholyte systems with low crosslinker densities. In a similar fashion, Jian and Matsumura were able to controllably tune the mechanical properties of their nanocomposite hydrogel designed with carboxylated poly- l -lysine (COOH-PLL), and synthetic clay laponite XLG, by changing the laponite concentration (composition dependence) or the density of the polyethylene glycol with N -hydroxy succinimide ester (PEG–NHS) crosslinker [17]. Changing the crosslinker density or monomer concentration are also common tuning mechanisms for mechanical properties [18,19,20,21,22].…”