{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,2]],"date-time":"2026-05-02T06:14:10Z","timestamp":1777702450293,"version":"3.51.4"},"reference-count":43,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2016,10,19]],"date-time":"2016-10-19T00:00:00Z","timestamp":1476835200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000824","name":"Home Office","doi-asserted-by":"publisher","award":["SBRI_HO_202_007 (HOS\/14\/003)"],"award-info":[{"award-number":["SBRI_HO_202_007 (HOS\/14\/003)"]}],"id":[{"id":"10.13039\/501100000824","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Surface-enhanced Raman spectroscopy (SERS) substrates manufactured using complex nano-patterning techniques have become the norm. However, their cost of manufacture makes them unaffordable to incorporate into most biosensors. The technique shown in this paper is low-cost, reliable and highly sensitive. Chemical etching of solid Ag metal was used to produce simple, yet robust SERS substrates with broadband characteristics. Etching with ammonium hydroxide (NH4OH) and nitric acid (HNO3) helped obtain roughened Ag SERS substrates. Scanning electron microscopy (SEM) and interferometry were used to visualize and quantify surface roughness. Flattened Ag wires had inherent, but non-uniform roughness having peaks and valleys in the microscale. NH4OH treatment removed dirt and smoothened the surface, while HNO3 treatment produced a flake-like morphology with visibly more surface roughness features on Ag metal. SERS efficacy was tested using 4-methylbenzenethiol (MBT). The best SERS enhancement for 1 mM MBT was observed for Ag metal etched for 30 s in NH4OH followed by 10 s in HNO3. Further, MBT could be quantified with detection limits of 1 pM and 100 \u00b5M, respectively, using 514 nm and 1064 nm Raman spectrometers. Thus, a rapid and less energy intensive method for producing solid Ag SERS substrate and its efficacy in analyte sensing was demonstrated.<\/jats:p>","DOI":"10.3390\/s16101742","type":"journal-article","created":{"date-parts":[[2016,10,19]],"date-time":"2016-10-19T10:32:57Z","timestamp":1476873177000},"page":"1742","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Chemically Roughened Solid Silver: A Simple, Robust and Broadband SERS Substrate"],"prefix":"10.3390","volume":"16","author":[{"given":"Shavini","family":"Wijesuriya","sequence":"first","affiliation":[{"name":"Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK"},{"name":"Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Krishna","family":"Burugapalli","sequence":"additional","affiliation":[{"name":"Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK"},{"name":"Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ruth","family":"Mackay","sequence":"additional","affiliation":[{"name":"Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK"},{"name":"Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Godwin","family":"Ajaezi","sequence":"additional","affiliation":[{"name":"Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wamadeva","family":"Balachandran","sequence":"additional","affiliation":[{"name":"Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK"},{"name":"Department of Electronic and Computer Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,10,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2224","DOI":"10.1039\/C3CP53560F","article-title":"Simple SERS substrates: Powerful, portable, and full of potential","volume":"16","author":"Betz","year":"2014","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.vacuum.2012.08.006","article-title":"Shelf time effect on SERS effectiveness of silver nanorod prepared by OAD technique","volume":"88","author":"Nuntawong","year":"2013","journal-title":"Vacuum"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.1007\/s00216-009-2761-5","article-title":"Surface-enhanced Raman spectroscopy: Substrate-related issues","volume":"394","author":"Lin","year":"2009","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1150","DOI":"10.1039\/C1JM14133C","article-title":"Gold-modified silver nanorod arrays: Growth dynamics and improved SERS properties","volume":"22","author":"Song","year":"2012","journal-title":"J. Mater. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"10208","DOI":"10.1038\/srep10208","article-title":"Low-Cost, Disposable, Flexible and Highly Reproducible Screen Printed SERS Substrates for the Detection of Various Chemicals","volume":"5","author":"Wu","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Le Ru, E.C., and Etchegoin, P.G. (2009). Principles of Surface-Enhanced Raman Spectroscopy, Elsevier.","DOI":"10.1016\/B978-0-444-52779-0.00005-2"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1667","DOI":"10.1103\/PhysRevLett.78.1667","article-title":"Single Molecule Detection Using Surface-Enhanced Raman Scattering (SERS)","volume":"78","author":"Kneipp","year":"1997","journal-title":"Physical Rev. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1102","DOI":"10.1126\/science.275.5303.1102","article-title":"Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering","volume":"275","author":"Nie","year":"1997","journal-title":"Science"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"604","DOI":"10.1002\/smll.200901820","article-title":"SERS-Based Diagnosis and Biodetection","volume":"6","year":"2010","journal-title":"Small"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1815","DOI":"10.1002\/elps.200700554","article-title":"Recent advances in surface-enhanced Raman scattering detection technology for microfluidic chips","volume":"29","author":"Chen","year":"2008","journal-title":"Electrophoresis"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/0009-2614(74)85388-1","article-title":"Raman spectra of pyridine adsorbed at a silver electrode","volume":"26","author":"Fleischmann","year":"1974","journal-title":"Chem. Phys. Lett."},{"key":"ref_12","unstructured":"Wet Chemical Etching. Available online: http:\/\/www.microchemicals.com\/technical_information\/wet_etching.pdf."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Tarn, W.H., and Walker, P. (1990). CRC Handbook of Metal. Etchants, CRC Press.","DOI":"10.1201\/9781439822531"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1305","DOI":"10.1039\/f19848001305","article-title":"Surface-enhanced Raman scattering and the preparation of copper substrates for catalytic studies","volume":"80","author":"Miller","year":"1984","journal-title":"J. Chem. Soc. Faraday Trans. 1"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"756","DOI":"10.1366\/0003702914336570","article-title":"Surface-Enhanced Raman Scattering (SERS) and Surface-Enhanced Resonance Raman Scattering (SERRS) on HNO3-Roughened Copper Foil","volume":"45","author":"Xue","year":"1991","journal-title":"Appl. Spectrosc."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2393","DOI":"10.1021\/ac00020a037","article-title":"Stable silver substrate prepared by the nitric acid etching method for a surface-enhanced Raman scattering study","volume":"63","author":"Xue","year":"1991","journal-title":"Anal. Chem."},{"key":"ref_17","first-page":"91","article-title":"Surface-enhanced Raman sensor","volume":"23","author":"Ruperez","year":"1995","journal-title":"Analusis"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/S0039-9140(96)02036-X","article-title":"Surface-enhanced Raman spectrometry of triamterene on a silver substrate prepared by the nitric acid etching method","volume":"44","author":"Ruperez","year":"1997","journal-title":"Talanta"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"592","DOI":"10.1002\/1096-9918(200008)30:1<592::AID-SIA856>3.0.CO;2-Z","article-title":"Study of experimental parameters for improved adsorbate detectability in SERS using etched silver substrates","volume":"30","author":"Laserna","year":"2000","journal-title":"Surf. Interface Anal."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/S1369-7021(12)70017-2","article-title":"SERS: Materials, applications, and the future","volume":"15","author":"Sharma","year":"2012","journal-title":"Mater. Today"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"601","DOI":"10.1146\/annurev.anchem.1.031207.112814","article-title":"Surface-Enhanced Raman Spectroscopy","volume":"1","author":"Stiles","year":"2008","journal-title":"Annu. Rev. Anal. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"485","DOI":"10.1002\/jrs.1362","article-title":"Surface-enhanced Raman spectroscopy: A brief retrospective","volume":"36","author":"Moskovits","year":"2005","journal-title":"J. Raman Spectrosc."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1143","DOI":"10.1088\/0953-8984\/4\/5\/001","article-title":"Surface-enhanced Raman scattering","volume":"4","author":"Otto","year":"1992","journal-title":"J. Phys. Condens. Matter"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1751","DOI":"10.1007\/s00216-005-3353-7","article-title":"Progress in plasmonic engineering of surface-enhanced Raman-scattering substrates toward ultra-trace analysis","volume":"382","author":"Baker","year":"2005","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_25","unstructured":"Surface Texture Parameters, Zygo, Electronic Resource No. OMP-0514C 04\/2013. Available online: http:\/\/www.zygo.com\/library\/papers\/SurfText.pdf."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"888","DOI":"10.1016\/j.biomaterials.2012.10.049","article-title":"Electrospun fibro-porous polyurethane coatings for implantable glucose biosensors","volume":"34","author":"Wang","year":"2013","journal-title":"Biomaterials"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/j.memsci.2012.09.052","article-title":"Tailored fibro-porous structure of electrospun polyurethane membranes, their size-dependent properties and trans-membrane glucose diffusion","volume":"427","author":"Wang","year":"2013","journal-title":"J. Memb. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"015002","DOI":"10.1088\/1758-5082\/6\/1\/015002","article-title":"Electrospun polyurethane-core and gelatin-shell coaxial fibre coatings for miniature implantable biosensors","volume":"6","author":"Wang","year":"2014","journal-title":"Biofabrication"},{"key":"ref_29","unstructured":"Challa, S.S.R.K. (2012). Raman Spectroscopy for Nanomaterials Characterization, Springer."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"5863","DOI":"10.1007\/s11051-011-0493-x","article-title":"Fabrication of nanostructured silver substrates for surface-enhanced Raman spectroscopy","volume":"13","author":"Gellini","year":"2011","journal-title":"J. Nanopart. Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"14441","DOI":"10.1021\/la302795r","article-title":"A Chemical Route to Increase Hot Spots on Silver Nanowires for Surface-Enhanced Raman Spectroscopy Application","volume":"28","author":"Goh","year":"2012","journal-title":"Langmuir"},{"key":"ref_32","unstructured":"Lowe, H.F., and Spindloe, C. (2006\/2007). Central Laser Facility, Annual Report (RAL-TR-2007\u2013025), Rutherford Appleton Laboratory."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1007\/s11665-009-9352-7","article-title":"Nature of Surface Changes in Stamping Tools of Gray and Ductile Cast Iron During Gas and Plasma Nitrocarburizing","volume":"18","author":"Rolinski","year":"2009","journal-title":"J. Mater. Eng. Perform."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"833","DOI":"10.1080\/00032719.2013.850089","article-title":"Improved Surface Enhanced Raman Scattering for Nanostructured Silver on Porous Silicon for Ultrasensitive Determination of 2,4,6-Trinitrotoluene","volume":"47","author":"Lai","year":"2014","journal-title":"Anal. Lett."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0022-0728(77)80224-6","article-title":"Surface raman spectroelectrochemistry: Part I. Heterocyclic, aromatic, and aliphatic amines adsorbed on the anodized silver electrode","volume":"84","author":"Jeanmaire","year":"1977","journal-title":"J. Electroanal. Chem. Interfacial Electrochem."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/S0169-4332(97)00417-0","article-title":"Study of surface catalytic photochemical reaction by using conventional and Fourier transform surface enhanced Raman scattering","volume":"125","author":"Lu","year":"1998","journal-title":"Appl. Surf. Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/j.mee.2013.02.033","article-title":"Hollow metallic pyramid plasmonic structures fabricated by direct laser writing and electron beam evaporation","volume":"110","author":"Jiajia","year":"2013","journal-title":"Microelectr. Eng."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2599","DOI":"10.1021\/jz4012383","article-title":"A Look at the Origin and Magnitude of the Chemical Contribution to the Enhancement Mechanism of Surface-Enhanced Raman Spectroscopy (SERS): Theory and Experiment","volume":"4","author":"Valley","year":"2013","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"5800","DOI":"10.1021\/bi00073a012","article-title":"Determination of the pKa values of active-center cysteines, cysteines-32 and -35, in Escherichia coli thioredoxin by Raman spectroscopy","volume":"32","author":"Li","year":"1993","journal-title":"Biochemistry"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"750","DOI":"10.1039\/B301032P","article-title":"The air-liquid interface of benzene, toluene, m-xylene, and mesitylene: A sum frequency, Raman, and infrared spectroscopic study","volume":"128","author":"Hommel","year":"2003","journal-title":"Analyst"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"093110","DOI":"10.1063\/1.2837543","article-title":"Tip-enhanced Raman scattering of p-thiocresol molecules on individual gold nanoparticles","volume":"92","author":"Chen","year":"2008","journal-title":"Appl. Phys. Lett."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1557\/mrs.2013.161","article-title":"High-performance SERS substrates: Advances and challenges","volume":"38","author":"Sharma","year":"2013","journal-title":"MRS Bull."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1500142","DOI":"10.1002\/admi.201500142","article-title":"Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface-Enhanced Raman Spectroscopy Substrate for \u201cAll\u201d Excitation Wavelengths","volume":"2","author":"Zhang","year":"2015","journal-title":"Adv. Mater. Interfaces"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/10\/1742\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:33:27Z","timestamp":1760211207000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/10\/1742"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,10,19]]},"references-count":43,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2016,10]]}},"alternative-id":["s16101742"],"URL":"https:\/\/doi.org\/10.3390\/s16101742","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,10,19]]}}}