{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T10:29:20Z","timestamp":1768472960418,"version":"3.49.0"},"reference-count":28,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2019,3,31]],"date-time":"2019-03-31T00:00:00Z","timestamp":1553990400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["No.21475097 and 21471116"],"award-info":[{"award-number":["No.21475097 and 21471116"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004731","name":"Natural Science Foundation of Zhejiang Province","doi-asserted-by":"publisher","award":["LY17B050004, LY18H200025 and LY17E020003"],"award-info":[{"award-number":["LY17B050004, LY18H200025 and LY17E020003"]}],"id":[{"id":"10.13039\/501100004731","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Opening Project of Zhejiang Provincial Top Key Discipline of Clinical Medicine","award":["KFJ026"],"award-info":[{"award-number":["KFJ026"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A highly sensitive immunoassay of biomarkers has been achieved using 4-mercaptobenzoic acid-labeled Ag@Au core\u2013shell porous nanocage tags and \u03b1-fetoprotein immuno-sensing chips. The Ag@Au porous nanocages were uniquely synthesized by using an Ag core as a self-sacrificial template and reducing agent, where the slow reaction process led to the formation of a porous Au layer. The size of the remaining Ag core and surface roughness of the Au shell were controlled by adjusting the chloroauric acid concentration. The porous cage exhibited excellent surface-enhanced Raman spectroscopy (SERS) activity, presumably due to a synergetic interaction between newly generated hot spots in the rough Au shell and the retained SERS activity of the Ag core. Using \u03b1-fetoprotein as a model analyte for immunoassay, the SERS signal had a wide linear range of 0.20 ng mL\u22121 to 500.0 ng mL\u22121 with a detection limit of 0.12 ng mL\u22121. Without the need of further signal amplification, the as-prepared Ag@Au bimetallic nanocages can be directly used for highly sensitive SERS assays of other biomarkers in biomedical research, diagnostics, etc.<\/jats:p>","DOI":"10.3390\/s19071554","type":"journal-article","created":{"date-parts":[[2019,4,2]],"date-time":"2019-04-02T03:21:26Z","timestamp":1554175286000},"page":"1554","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Ag@Au Core\u2013Shell Porous Nanocages with Outstanding SERS Activity for Highly Sensitive SERS Immunoassay"],"prefix":"10.3390","volume":"19","author":[{"given":"Yaqi","family":"Huang","sequence":"first","affiliation":[{"name":"College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China"}]},{"given":"Dajie","family":"Lin","sequence":"additional","affiliation":[{"name":"College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China"},{"name":"Key Laboratory of Laboratory Medicine (Ministry of Education of China), Wenzhou Medical University, Wenzhou 325037, China"}]},{"given":"Mengting","family":"Li","sequence":"additional","affiliation":[{"name":"College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China"}]},{"given":"Dewu","family":"Yin","sequence":"additional","affiliation":[{"name":"College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China"}]},{"given":"Shun","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China"}]},{"given":"Jichang","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China"},{"name":"Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada"}]}],"member":"1968","published-online":{"date-parts":[[2019,3,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"698","DOI":"10.1016\/S1470-2045(01)00560-5","article-title":"Trends in biomarker research for cancer detection","volume":"2","author":"Srinivas","year":"2001","journal-title":"Lancet Oncol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1662","DOI":"10.1126\/science.1069492","article-title":"Systems Biology: A Brief Overview","volume":"295","author":"Kitano","year":"2002","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1402","DOI":"10.1002\/elan.200603868","article-title":"A Reagentless Amperometric Immunosensor for Alpha-Fetoprotein Based on Gold Nanoparticles\/TiO2 Colloids\/Prussian Blue Modified Platinum Electrode","volume":"19","author":"Yuan","year":"2007","journal-title":"Electroanalysis"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2595","DOI":"10.1002\/smll.201202957","article-title":"Carbon nanotubes multifunctionalized by rolling circle amplification and their application for highly sensitive detection of cancer markers","volume":"9","author":"Zhao","year":"2013","journal-title":"Small"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"7337","DOI":"10.1021\/ac500054x","article-title":"Ultrasensitive electrochemical detection of prostate-specific antigen by using antibodies anchored on a DNA nanostructural scaffold","volume":"86","author":"Chen","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.bios.2014.10.074","article-title":"Cascade signal amplification for electrochemical immunosensing by integrating biobarcode probes, surface-initiated enzymatic polymerization and silver nanoparticle deposition","volume":"66","author":"Lin","year":"2015","journal-title":"Biosens. Bioelectron."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/j.bios.2017.06.047","article-title":"A novel signal-on photoelectrochemical immunosensor for detection of alpha-fetoprotein by in situ releasing electron donor","volume":"98","author":"Chen","year":"2017","journal-title":"Biosens. Bioelectron."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"4489","DOI":"10.1021\/ac3003215","article-title":"Enhancement of immunoassay\u2019s fluorescence and detection sensitivity using three-dimensional plasmonic nano-antenna-dots array","volume":"84","author":"Zhou","year":"2012","journal-title":"Anal. Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5131","DOI":"10.1021\/acs.analchem.6b00048","article-title":"Redox-mediated Indirect Fluorescence Immunoassay for the Detection of Disease Biomarkers Using Dopamine-functionalized QDs","volume":"88","author":"Zhang","year":"2016","journal-title":"Anal. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1016\/j.snb.2017.10.115","article-title":"Simultaneous detection of multiple tumor markers by label-free electrochemical immunoassay using chip-like glass carbon electrodes","volume":"256","author":"Wang","year":"2018","journal-title":"Sens. Actuators B Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5214","DOI":"10.1021\/ac200398x","article-title":"Ultrasensitive immunoassay of protein biomarker based on electrochemiluminescent quenching of quantum dots by hemin bio-bar-coded nanoparticle tags","volume":"83","author":"Dajie","year":"2011","journal-title":"Anal. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.bios.2014.04.026","article-title":"Development of nanobody-based flow injection chemiluminescence immunoassay for sensitive detection of human prealbumin","volume":"61","author":"Lei","year":"2014","journal-title":"Biosens. Bioelectron."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2313","DOI":"10.1021\/acsnano.6b06040","article-title":"Diverse Applications of Nanomedicine","volume":"11","author":"Pelaz","year":"2017","journal-title":"ACS Nano"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2431","DOI":"10.1002\/adma.201305106","article-title":"Highly sensitive, uniform, and reproducible surface-enhanced Raman spectroscopy from hollow Au-Ag alloy nanourchins","volume":"26","author":"Liu","year":"2014","journal-title":"Adv. Mater."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"10489","DOI":"10.1021\/acs.chemrev.5b00265","article-title":"SERS Nanoparticles in Medicine: From Label-Free Detection to Spectroscopic Tagging","volume":"115","author":"Lane","year":"2015","journal-title":"Chem. Rev."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2640","DOI":"10.1039\/C6NR07979B","article-title":"An enzyme-induced Au@Ag core\u2013shell nanoStructure used for an ultrasensitive surface-enhanced Raman scattering immunoassay of cancer biomarkers","volume":"9","author":"Yang","year":"2017","journal-title":"Nanoscale"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"3465","DOI":"10.1021\/acs.analchem.5b04873","article-title":"Use of Multiple Peptide-Based SERS Probes Binding to Different Epitopes on a Protein Biomarker to Improve Detection Sensitivity","volume":"88","author":"Shin","year":"2016","journal-title":"Anal. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1391","DOI":"10.1021\/cr300120g","article-title":"SERS tags: Novel optical nanoprobes for bioanalysis","volume":"113","author":"Wang","year":"2013","journal-title":"Chem. Rev."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"922","DOI":"10.1039\/c1ib00029b","article-title":"Intracellular mapping with SERS-encoded gold nanostars","volume":"3","author":"Krpetic","year":"2011","journal-title":"Integr. Biol."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Mohd Azmi, U.Z., Yusof, N.A., Kusnin, N., Abdullah, J., Suraiya, S., Ong, P.S., Ahmad Raston, N.H., Abd Rahman, S.F., and Mohamad Fathil, M.F. (2018). Sandwich Electrochemical Immunosensor for Early Detection of Tuberculosis Based on Graphene\/Polyaniline-Modified Screen-Printed Gold Electrode. Sensors, 18.","DOI":"10.3390\/s18113926"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5983","DOI":"10.1039\/C7TB01212H","article-title":"Hollow Au nanoflower substrates for identification and discrimination of the differentiation of bone marrow mesenchymal stem cells by surface-enhanced Raman spectroscopy","volume":"5","author":"Cao","year":"2017","journal-title":"J. Mater. Chem. B"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"15591","DOI":"10.1021\/acsami.6b02905","article-title":"Nanoshell-Enhanced Raman Spectroscopy on a Microplate for Staphylococcal Enterotoxin B Sensing","volume":"8","author":"Wang","year":"2016","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"10683","DOI":"10.1021\/acsami.6b00450","article-title":"Sensitive Glycoprotein Sandwich Assays by the Synergistic Effect of In Situ Generation of Raman Probes and Plasmonic Coupling of Ag Core-Au Satellite Nanostructures","volume":"8","author":"Bi","year":"2016","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"780","DOI":"10.1016\/j.saa.2007.09.016","article-title":"Synthesis, characterization and SERS activity of Au-Ag nanorods","volume":"70","author":"Philip","year":"2008","journal-title":"Spectrochim. Acta A Mol. Biomol. Spectrosc."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1224","DOI":"10.1021\/jp036301n","article-title":"Optical Properties of Metal Nanoshells","volume":"108","author":"Hao","year":"2004","journal-title":"J. Phys. Chem. B"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2498","DOI":"10.1021\/la4047148","article-title":"Synthesis of monodisperse, quasi-spherical silver nanoparticles with sizes defined by the nature of silver precursors","volume":"30","author":"Li","year":"2014","journal-title":"Langmuir"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"9928","DOI":"10.1021\/la0009588","article-title":"Core\u2212Shell (Ag)Au Bimetallic Nanoparticles:\u2009 Analysis of Transmission Electron Microscopy Images","volume":"16","author":"Gemperle","year":"2000","journal-title":"Langmuir"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"7134","DOI":"10.1021\/la400753q","article-title":"Bimetallic Ag-Au nanowires: Synthesis, growth mechanism, and catalytic properties","volume":"29","author":"Fu","year":"2013","journal-title":"Langmuir"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/7\/1554\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:41:52Z","timestamp":1760186512000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/7\/1554"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,3,31]]},"references-count":28,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2019,4]]}},"alternative-id":["s19071554"],"URL":"https:\/\/doi.org\/10.3390\/s19071554","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,3,31]]}}}