Poly(vinyl alcohol) nanocarriers

A nanoparticle comprising:

• at least one poly(vinyl alcohol) (PVA) having a molecular weight of from about 10 kDa to about 200 kDa, substituted with one or more moieties of
• a therapeutic agent having a boronic acid moiety, wherein the therapeutic agent is covalently linked to the PVA via a boronate ester bond,
• wherein the PVA has a structure according to formula I:
• wherein:
• each R′ is independently selected from the group consisting of H and a moiety according to formula Ia:
• wherein L is a linking moiety and R1a is a therapeutic moiety,
• provided that at least one R′ is H and at least one R′ is other than H;
• each R2 is independently selected from the group consisting of —OH, a cellular targeting moiety, and an imaging moiety, or any two adjacent R2 moieties are taken together to form a cellular targeting moiety or an imaging moiety;
• subscript x is an integer of from about 1 to about 1200, and
• subscript y is an integer of from 0 to about 3800, wherein
• the sum of x and y is an integer of from about 200 to about 5000, and the x and y repeating units are randomly distributed in the PVA.