A nanoparticle comprising a first polymer comprising alternating charged and uncharged segments comprising one or more of the following structural units of Formula or Formula or Formula: wherein A is the uncharged segment comprising a polyalkylene glycol; B is the charged segment wherein the charged segment is cationically charged and comprises at least one polyhydroxy linkage comprising at least one pair of vicinal diols; wherein the nanoparticle further comprises an encapsulated biological agent, optionally wherein the biological agent is covalently bound to the polymer; and wherein the nanoparticle optionally comprises a second polymer comprising a boronic acid-containing structure of Formula conjugated to the first polymer wherein the first polymer and the second boronic acid-containing polymer are reversibly connected to one another by a borate condensation linkage between the boronic acid moieties of Formula and the at least one pair of vicinal diols of the polyhydroxy linkages of Formula, Formula or, X 5 being at a distal end thereof; wherein R A is nitro; n is 0, 1, 2, 3, or 4; s is 20-1200 L is -NH-C(=O)-, -C(=O)-NH-, -O-C(=O)-, or -C(=O)-O-; and X 5 is C 1-6 alkyl, optionally substituted with -OH, -COOH, -C(=O)O(alkyl), - C(=O)O(aryl), -NH 2, -NH(alkyl), -N (alkyl) 2, or a salt or protected analog thereof; and wherein if the nanoparticle comprises the polymer comprising the boronic acid-containing structure of Formula, the nanoparticle optionally further comprises a conjugated targeting ligand, wherein conjugation occurs through a condensation linkage between the distal end of the boronic acid-containing polymer and the targeting ligand; optionally wherein (a) A comprises polyethylene glycol and an appropriate linking group, wherein the polyethylene glycol has a nominal weight in a range of from about 500 Daltons to about 50,000 Daltons; (b) B is a cationically charged segment comprising at least one mucic acid linkage comprising the at least one pair of vicinal diols and comprising at least one repeating subunit comprising a structure of Formula: (c) B is a cationically charged segment comprising at least one repeating subunit comprising a structure of Formula: wherein m is 1, 2, 3, 4, 5, or 6; and/or (d) B comprises at least one repeating subunit comprising cMAP, whose subunit structure is represented as Formula: wherein m is independently at each occurrence 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; and n is independently at each occurrence 1, 2, 3, 4, or 5. A is the uncharged segment comprising a polyalkylene glycol; B is the charged segment wherein the charged segment is cationically charged and comprises at least one polyhydroxy linkage comprising at least one pair of vicinal diols; wherein the nanoparticle further comprises an encapsulated biological agent, optionally wherein the biological agent is covalently bound to the polymer; and wherein the nanoparticle optionally comprises a second polymer comprising a boronic acid-containing structure of Formula conjugated to the first polymer wherein the first polymer and the second boronic acid-containing polymer are reversibly connected to one another by a borate condensation linkage between the boronic acid moieties of Formula and the at least one pair of vicinal diols of the polyhydroxy linkages of Formula, Formula or, X 5 being at a distal end thereof; R A is nitro; n is 0, 1, 2, 3, or 4; s is 20-1200 L is -NH-C(=O)-, -C(=O)-NH-, -O-C(=O)-, or -C(=O)-O-; and X 5 is C 1-6 alkyl, optionally substituted with -OH, -COOH, -C(=O)O(alkyl), - C(=O)O(aryl), -NH 2, -NH(alkyl), -N (alkyl) 2, or a salt or protected analog thereof; and wherein if the nanoparticle comprises the polymer comprising the boronic acid-containing structure of Formula, the nanoparticle optionally further comprises a conjugated targeting ligand, wherein conjugation occurs through a condensation linkage between the distal end of the boronic acid-containing polymer and the targeting ligand; optionally wherein (a) A comprises polyethylene glycol and an appropriate linking group, wherein the polyethylene glycol has a nominal weight in a range of from about 500 Daltons to about 50,000 Daltons; (b) B is a cationically charged segment comprising at least one mucic acid linkage comprising the at least one pair of vicinal diols and comprising at least one repeating subunit comprising a structure of Formula: (c) B is a cationically charged segment comprising at least one repeating subunit comprising a structure of Formula: wherein m is 1, 2, 3, 4, 5, or 6; and/or (d) B comprises at least one repeating subunit comprising cMAP, whose subunit structure is represented as Formula: (a) A comprises polyethylene glycol and an appropriate linking group, wherein the polyethylene glycol has a nominal weight in a range of from about 500 Daltons to about 50,000 Daltons; (b) B is a cationically charged segment comprising at least one mucic acid linkage comprising the at least one pair of vicinal diols and comprising at least one repeating subunit comprising a structure of Formula: (c) B is a cationically charged segment comprising at least one repeating subunit comprising a structure of Formula: wherein m is 1, 2, 3, 4, 5, or 6; and/or (d) B comprises at least one repeating subunit comprising cMAP, whose subunit structure is represented as Formula: m is independently at each occurrence 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; and n is independently at each occurrence 1, 2, 3, 4, or 5.