A systematic study was conducted for in situ synthesis of. ne Pb nanoparticles in aqueous gelatin solution and in pre-organized gel of polyacrylamide. The Pb nanoparticles stabilized by gelatin or trapped in polyacrylamide matrix transfer electron to O-2 and methyl viologen (paraquat; 1,1'-dimethyl-4,4'-dipyridinium dichloride; MV2+(Cl )(2)). Lead nanoparticles were probed for their magnetic characteristics by superconducting quantum interference device (SQUID) magnetometer and display superconductivity with a critical temperature T-c of about 7.1 K. The magnetization measurements reveal the superconducting behaviour of Pb nanoparticles prepared in aqueous gelatin stabilized sol and corroborates the results obtained from electron transfer reactions. (C) 2009 Elsevier B. V. All rights reserved.