TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Preparation of (A) comprises:(a) making an aqueous solution of bis(2,2'-bipyridine)ruthenium(II)bis(pyrazolyl); and(b) injecting a solution containing polystyrene-b-poly(L-isocyanoalanine(2-thiophen-3-yl-ethyl)amide) in tetrahydrofuran into the aqueous solution.Preferred Process: The preparation of (A), further comprises (c) placing the dispersion produced in step (b) at 60 degreesC; (d) cooling the dispersion to room temperature, and (e) filtering the dispersion using a filter with a cutoff of 100 kDa.Preferred Components: (A) comprises more then one hollow particle. The density of the hollow particles in (A) is such that the majority of the hollow particles are in close contact to each other. The hollow particle is a vesicle such as a polymersome. The shell of the hollow particle is conductive polymer and comprises a block-copolymer. The block-copolymer comprises a hydrophobic polystyrene block and a hydrophilic polyisocyanopeptide; preferably polystyrene-b-poly(L-isocyanoalanine(2-thiophen-3-yl-ethyl)amide) (PS-PIAT). The side groups present on the block copolymer are polymerized; preferably the thiophene side groups present in the side chain of polystyrene-b-poly(L-isocyanoalanine(2-thiophen-3-ylethyl)amide) are polymerized. The polypeptide is linked to the inner side of the hollow particle. The polypeptide is an enzyme (glucose oxidase) and is capable of participating in a chemical reaction or is capable in participating in the formation of a molecular structure that facilitates such reaction. The chemical reaction is a redox or an oxidation reaction. The hollow particle is permeable to a substrate (glucose) of the glucose oxidase and is embedded in a gel-like structure or a glucose solution.(A) comprises a matrix (a linear conductive polymer, to contact the hollow particle by cross-linking at least one hollow particle to another hollow particle) and electron carriers such as ferrocene derivatives and viologen derivatives. In the device, the solute is glucose. EXAMPLE - No relevant example given.