Methods　based　on　sandwich-type　immunosensors　and　immunoassays　have　been　developed　for　detection　of　multivalent　antigens/analytes　with　more　than　one　eptiope　due　to　the　use　of　two　matched　antibodies.　High-affinity　antibodies　and　appropriate　labels　are　usually　employed　for　the　amplification　of　detectable　signal.　Recent　research　has　looked　to　develop　innovative　and　powerful　novel　nanoparticle　labels,　controlling　and　tailoring　their　properties　in　a　very　predictable　manner　to　meet　the　requirements　of　specific　applications.　This　articles　reviews　recent　advances,　exploiting　nanoparticle　labels,　in　the　sandwich-type　immunosensors　and　immunoassays.　Routine　approaches　involve　noble　metal　nanoparticles,　carbon　nanomaterials,　semiconductor　nanoparticles,　metal　oxide　nanostructures,　and　hybrid　nanostructures.　The　enormous　signal　enhancement　associated　with　the　use　of　nanoparticle　labels　and　with　the　formation　of　nanoparticle-antibody-antigen　assemblies　provides　the　basis　for　sensitive　detection　of　disease-related　proteins　or　biomolecules.　Techniques　commonly　rely　on　the　use　of　biofunctionalized　nanoparticles,　inorganic-biological　hybrid　nanoparticles,　and　signal　tag-doped　nanoparticles.　Rather　than　being　exhaustive,　this　review　focuses　on　selected　examples　to　illustrate　novel　concepts　and　promising　applications.　Approaches　described　include　the　biofunctionalized　nanoparticles,　inorganic-biological　hybrid　nanoparticles,　and　signal　tage-doped　nanoparticles.　Further,　promising　application　in　electrochemical,　mass-sensitive,　optical　and　multianalyte　detection　are　discussed　in　detail.　(C)　2012　Elsevier　B.V.　All　rights　reserved.