Self-assembled colloidal gel using cell membrane-coated nanosponges as building blocks

Summary

This study tests whether membrane-coated nanosponges can serve as the structural units of an injectable therapeutic gel without chemical cross-linkers. Red-blood-cell membrane-coated nanoparticles were mixed with oppositely charged cationic particles, causing spontaneous electrostatic self-assembly into a gel-like network. Rheological testing showed pronounced shear thinning, a property compatible with passage through a needle. Importantly, assembly did not eliminate the nanosponges' capacity to neutralize toxins. After subcutaneous injection in mice, the gel retained the nanosponges locally for longer than a non-gelled formulation. In a mouse model of subcutaneous group A Streptococcus infection, treatment reduced development of skin lesions, supporting local antibacterial benefit through an antivirulence mechanism. The principal result is therefore a chemically uncross-linked depot that combines injectability, prolonged local residence, and preserved toxin capture. This may be useful where localized infection requires sustained action while limiting systemic exposure. However, the abstract gives no numerical rheology, retention, bacterial burden, lesion, or safety data; sample sizes and controls are unspecified. Results concern one membrane source and one infection model, and the contribution of cationic particles, biodegradation, repeat dosing, sterilization, manufacturing reproducibility, and human tissue compatibility remain unclear.