Abstract: The present invention relates to a method of in vivo optical imaging, of the margins around tumours, which comprises an optical imaging contrast agent. The optical imaging agents comprise conjugates of near-infrared dyes with synthetic polyethylene glycol (PEG) polymers having a molecular weight in the range 15-45 kDa. Also disclosed are optical imaging contrast agents, pharmaceutical compositions and kits.

Abstract: In one aspect, the present invention provides a functionalized monodisperse polylysine comprising a linear monodisperse polylysine chain comprising constituent lysine monomer residues containing appended C4-C24 polyethylene glycol groups and at least one appended fluorescent dye moiety is provided.

Abstract: System for delivery of a biologically active substance into an environment. First and second chambers are separated by a moveable partition. The first chamber includes a polymer gel network which undergoes a volume change in response to an environmental condition such as pH. The first compartment includes a screen or membrane for confining the polymer gel network while allowing communication with fluid in an environment. The second compartment contains a biologically active compound or drug which is delivered to the environment through an orifice in the second compartment. Upon the occurrence of the triggering environmental condition, the polymer gel network undergoes a volume change which moves the moveable partition expelling the drug through the orifice. Drug delivery is initiated and continues only when the appropriate environmental condition or trigger is met.