<unk> s that contain active enzymes and that provide a way to selectively transport substrates for conversion by those enzymes have been described as nanoreactors.<unk> s have been used to create controlled release drug delivery systems. Similar to coating liposomes with polyethylene glycol,<unk> s can be made invisible to the immune system if the hydrophilic block consists of polyethylene glycol. Thus,<unk> s are useful carriers for targeted medication. For in vivo applications,<unk> s are de facto limited to the use of FDA-approved polymers, as most pharmaceutical firms are unlikely to develop novel polymers due to cost issues. Fortunately, there are a number of such polymers available, with varying properties, including: Hydrophilic blocks * Poly(ethylene glycol) (PEG/PEO) * Poly(2-methyloxazoline) Hydrophobic blocks * Polydimethylsiloxane (PDMS) * Poly(caprolactone (PCL) * Poly(lactide) (PLA) * Poly(methyl methacrylate) (PMMA) If enough of the block copolymer molecules that make up a<unk>  are cross-linked, the<unk>  can be made into a transportable powder.<unk> s can be used to make an artificial cell if hemoglobin and other components are added. The first artificial cell was made by Thomas Chang.
Polymersome
Bioptome
Polysome
Trabectome
Cubosome
Microkeratome
Melanosome
Nuclear bag fiber