Methacrylated Gellan Gum/Poly-l-lysine Polyelectrolyte Complex Beads for Cell-Based Therapies

Abstract

Cell encapsulation strategies using hydrogel beads have been considered as an alternative to immunosuppression in cell-based therapies. They rely on layer-by-layer (LbL) deposition of polymers to tune beads' permeability, creating a physical barrier to the host immune system. However, the LbL approach can also create diffusion barriers, hampering the flow of essential nutrients and therapeutic cell products. In this work, the polyelectrolyte complex (PEC) methodology was used to circumvent the drawbacks of the LbL strategy by inducing hydrogel bead formation through the interaction of anionic methacrylated gellan gum (GG-MA) with cationic poly-L-lysine (PLL). The interfacial complexation between both polymers resulted in beads with a cell-friendly GG-MA hydrogel core surrounded by a PEC semipermeable membrane. The beads showed great in vitro stability over time, a semipermeable behavior, and supported human adipose-derived stem cell encapsulation. Additionally, and regarding immune recognition, the in vitro and in vivo studies pointed out that the hydrogel beads behave as an immunocompatible system. Overall, the engineered beads showed great potential for hydrogel-mediated cell therapies, when immunoprotection is required, as when treating different metabolic disorders.

Surface Functionalized Polyaniline Nanofibers:Chitosan Nanocomposite for Promoting Neuronal-like Differentiation of Primary Adipose Derived Mesenchymal Stem Cells and Urease Activity

“…To get an idea about possible immune response that may be evoked by the fabricated nanocomposites scaffolds, immunocompatibility of the nonfunctionalized and functionalized PNF:Ch nanocomposites scaffolds was assessed using murine macrophages RAW 264.7 cells as per previous protocol. 80 In brief, 5 × 10 4 cells were seeded in a 24 well plate containing different scaffolds (size, 5 mm × 5 mm), where 250 ng of lipopolysaccharide (LPS) and nonstimulated tissue culture (NTC) were used as positive control and plate as negative control. After 24 and 48 h of treatment, conditioned media were collected and tested for the release of interleukin-1β (IL-1β) using an IL-1β ELISA kit according to the manufacturer's protocol (Invitrogen).…”

Fabrication of Oleophilic Polypeptide Nanoparticle from Complexing of Cross-Linked Epsilon-poly-l-lysine with Docusate Sodium for Preparation of Bactericidal Thermoplastic Polyurethanes

“…It is confirmed that EPL goes against bacteria through the membrane-lysis mechanism . To date, EPL has been developed for wound dressings, biomedical device coatings, food packaging, and so on. − However, the physicochemical properties and stability issues limit their therapeutic application in the biomedical field due to their ionic nature . Especially, a large quantity of EPL addition can induce phase separation or color change.…”

Oxygen-co-Thermal Driver for Constructing Integrated Anisotropic Hydrogels with Programmable Shape Deformation, Superior Self-Healing, and Mechanical Performance

“…Actually, besides the programmed structure, the preparation material of hydrogels is also crucial for smart hydrogel actuators. It is well-known that polyelectrolyte materials are widely used in the construction of functional hydrogels due to the ionic bonds between cross-linked polymer chains. , Current studies revealed that the electrostatic interactions between polymer chains drive the polyelectrolytes to spontaneously aggregate and exhibit phase separation behavior, , and this phase separation structure enriches the deformation diversity of anisotropic hydrogels as an auxiliary structure . Moreover, ionic bonds are often used to impart excellent mechanical and self-healing properties to hydrogels , due to their reversible nature and wide strength distribution .…”