Bimodal brush-functionalized nanoparticles selective to receptor surface density.

Area of Science:

• Biomaterials Science
• Nanotechnology
• Surface Chemistry

Background:

• Targeted drug delivery relies on nanoparticles selectively binding to cells with high receptor density.
• Bimodal polymer monolayers (BM) on nanoparticles are theoretically proposed to enhance this selectivity.
• Experimental validation of BM-functionalized nanoparticle selectivity under controlled conditions is lacking.

Purpose of the Study:

• To experimentally demonstrate and quantify the enhanced selectivity of BM-functionalized nanoparticles for target cells.
• To investigate the impact of protective chain length and molar ratio in BM on nanoparticle selectivity.
• To develop a theoretical model supporting the observed selectivity mechanisms.

Main Methods:

• Utilizing surface chemistry to create well-defined platforms mimicking the nanoparticle-cell interface.
• Employing surface plasmon resonance (SPR) and atomic force microscopy (AFM) to assess nanoparticle adsorption.
• Developing a theoretical model for protective brush repulsion and integrating it with super-selectivity theory.

Main Results:

• BM-functionalized nanoparticles exhibited selective adsorption to surfaces mimicking target cells.
• Enhanced selectivity was observed with longer protective chains in the bimodal polymer monolayer.
• A theoretical model confirmed that a steric energy barrier, requiring numerous ligand-receptor bonds, drives selectivity.

Conclusions:

• The relative length and molar ratio of polymer chains in BM can be tuned for targeted receptor density.
• This study provides experimental proof and a theoretical framework for designing BM-functionalized nanoparticles for selective cell targeting.
• Findings lay the groundwork for rational design of nanoparticles for pathological condition targeting.