The present disclosure is directed to nanoparticle delivery systems for delivering biological agents, pharmaceutical compositions of comprising these nanoparticles, and methods of using these compositions. Certain embodiments of the present disclosure provide nanoparticles comprising polymers comprising alternating charged and uncharged segments comprising one or more of the following structural units of Formula (I) Formula (III):wherein A is an uncharged segment comprising polyalkylene glycol； and B is a cationically charged segment comprising at least one polyhydroxy linkage.
