The present invention provides a method for the covalent immobilization of biomolecules on polymers for delivery of the biomolecules, which has the 
advantage of being simple, highly efficient, 
environmentally friendly and free of side products relative to traditional immobilization techniques. The invention provides a modified micro / 
nanoparticle system, which uses a 
functionalized polymer formed into micro or nanoparticles to bind a molecule to the particles using uses facile 
chemistry, the Diels-
Alder cycloaddition between a 
diene and a dienophile with the 
polymer being functionalized with one of them and the molecule with the other, or the Huisgen 1,3-dipolar 
cycloaddition between a terminal 
alkyne and an 
azide to bind the molecule to the particle. The molecules and / or other therapeutic agents may be encapsulated within the 
polymer particles for intravenous therapeutic delivery. The invention also provides a novel synthetic 
biodegradable polymer, a 
furan / 
alkyne-functionalized poly(
trimethylene carbonate) (PTMC)-based 
polymer, whose composition can be designed to meet the defined physical and 
chemical property requirements. In one example, the 
particle system self-aggregates from functionalized PTMC-based copolymers containing poly(
ethylene glycol) (PEG) segments. The composition of the copolymers can be designed to meet various 
particle system requirements, including size, thermodynamic stability, surface PEG density, 
drug encapsulation capacity and 
biomolecule immobilization capacity.