Nanoparticle conjugates

A conjugate comprising a drug molecule, biological molecule or cell bound to a photoluminescent polymer nanoparticle,

• wherein the drug molecule, biological molecule or cell is bound to the photoluminescent polymer nanoparticle by
• a covalent bond formed by the reaction of functional groups present on the photoluminescent polymer nanoparticle with functional groups present on the drug molecule, biological molecule or cell;
• and wherein the photoluminescent polymer nanoparticle is formed from a π-conjugated cross-linked polymer or a salt thereof, the π-conjugated cross-linked polymer comprising
• a) 80-99.9 mol. % of π-conjugated monomers, and
• b) 0.1-10 mol. % of a cross-linker having the formula III shown below:
• and
• c) one or more functional groups capable of reacting with functional groups on the drug molecule, biological molecule or cell to form a covalent bond linking the nanoparticle to the drug molecule, biological molecule or cell or a first moiety capable of affinity pairing with a second moiety present on the drug molecule, biological molecule or cell;
• wherein the π-conjugated monomers each independently have a structure according to formula IV shown below:
• wherein
• R1 and R2 are each independently hydrogen or a group:
• —X-Q
• wherein
• X is absent or selected from the group consisting of (1-30C)alkylene, —O-(1-30C)alkylene, —S-(1-30C)alkylene, —NH-(1-30C)alkylene, (2-30C)alkenylene, (2-30C)alkynylene, —[(CH2)2—O]n—, —[O—(CH2)2]n—, —[O—CH2MeCH2]n—, —[CH2MeCH2—O]n— and —[O—Si(Rz)2]n, wherein Rz is (1-4C)alkyl and n is 1 to 30, —[(CH2)n′—(CF2)m′]—, wherein n′ is 0-20 and m′ is 1 to 30;
• and
• Q is a terminal group selected from the following substituents, or a salt thereof:
• hydrogen, halogen, methyl, hydroxyl, carboxy, (1-4C)alkoxycarbonyl, amino, —CH═CH2, —C≡CH, —SH, biotin, streptavidin, antibody, —CF3, —OSO3H, —SO3H, —OPO2OH and zwitterions and a polymerisable group selected from silane, siloxane, acrylate, epoxy, styrene;
• or R1 and R2 are aryl or heteroaryl groups optionally substituted with a substituent group;
• or R1 and R2 are linked so that, together with the carbon atom to which they are attached, they form ring system optionally substituted with a substituent group;
• and with the proviso that, in at least one monomer of formula IV, Q is or comprises a group selected from the following substituents, or a salt thereof:
• amino, carboxy, hydroxyl, halogen, vinyl, alkenyl, alkynyl, carbonyl, thiol, biotin, streptavidin, an antibody or a polymerisable group selected from acrylate, epoxy, and styrene.