The present invention provides a nanoparticle including at least one polyvinyl alcohol) (PVA) having a molecular weight of from about 10 kDa to about 200 kDa, substituted with one or more moieties selected from: a therapeutic agent having a boronic acid moiety, wherein the therapeutic agent is covalently linked to the PVA via a boronate ester bond a crosslinking group having a disulfide moiety, wherein the crosslinking group is covalently linked to the PVA, and a porphyrin, wherein the porphyrin is covalently linked to the PVA. Use of the nanoparticles for tumor detection and the treatment of diseases, including methods for photodynamic therapy and photothermal therapy, are also described.
