Table 1 List of published work where SERS surfaces are integrated into microfluidic channel.
Author [reference] year | SERS fabrication method | Device material | Channel fabrication method | Analyte and minimum conc. measured or EF | SERS surface generated in situ (in channel)? |
|---|---|---|---|---|---|
Mackenzie et al. [this paper] | Ultrafast laser photoreduction of Ag+ | Fused silica | Ultrafast laser inscription then chemical etching | 1 mM R6G (Rhodamine 6G) On surface AEF ~1 × 1011 | yes |
Liu et al.60 2005 | Ag thin film on nanowells in PDMS | glass | Bonding of glass and Ag film on textures PDMS | R6G EF 107 | no |
Connatser et al.61 2008 | Electron beam lithography/Physical vapour deposition (PVD) of silver metal onto glass slab | PDMS | Soft lithography then glass bonding of SERS surface | 70 nM Resorufin | no |
Xu et al.51 2011 | Femtosecond direct laser writing onto channel | Glass | Microchannel made in glass using photolithography and wet etching techniques. Sealed with PDMS film after AgNPs written | p-aminothiophenol (p-ATP) EF 4 × 108 | no |
Lee et al.62 2012 | Gold-patterned microarray and hollow gold nanospheres (HGNs) | PDMS | PDMS device made using soft lithography. Glass patterned with gold microarray wells, was fabricated by a photolithographic technique and bonded to PDMS | Alpha-fetoprotein (AFP) LOD 0–1 ng/mL | no |
Parisi et al.57 2013 | In situ electrodeposition of copper in microfluidic channels. Cu(OAc)2 and CTAB flowed through the channel, Cu and C nanowalls formed on the working electrode, AgNO3 solution was flowed through, galvanic replacement of Cu with Ag+, formation of AgNPs. | PDMS | Electrodes integrated into the channel were pre-patterned on Si substrate using standard photolithography and lift-off techniques. | 50 pM Crystal violet AEF 1.1 × 109 | yes, bonding step required first |
Kim et al.63 2014 | Gold film-over nanospheres (AuFON) | PDMS | Soft lithography then glass bonding of SERS surface | 1 nM BPE (trans-1,2-bis(4-pyridyl)ethylene) | no |
Kim et al.63 2014 | Gold nanorods and nanocubes incorporated directly into the microfluidic polymer layer | PDMS | Soft lithography with AuNPs embedded in elastomer then glass bonding of SERS surface | 1 mM BPE EF 4.1 × 107 | no |
Oh & Jeong64 2014 | Thin silver film thermally evaporated onto channel surface | PDMS | Unwanted Ag film removed by scotch tape. Ag coated PDMS channel boded to glass | Benzenethiol EF 1.1 × 107 | no |
Li et al.65 2014 | Nanoporous gold disks (NPGDs) fabricated on glass substrate using nanosphere lithography | PDMS | Bonding of glass containing NPGDs to PDMS | 1 μm R6G EF 106 | no |
Parisi et al.66 2015 | In situ galvanic replacement of a pre-patterned copper (Cu) substrate. Cu substrates pre-patterned on Si substrate using standard photolithography and lift-off techniques | PDMS | PDMS channel plasma bonded to the Si substrate containing the pre-patterned Cu substrates. AgO3 pumped through channel for galvanic replacement of pre-patterned Cu with Ag + until dense layer of AgNPs form. | Crystal violet AEF 2.2 × 107 | yes, bonding step required first |
Novara et al.67 2016 | Electrochemical etching of a silicon wafer in HF electrolyte, followed by immersion plating in silver nitrate solution | PDMS | Bonding of PDMS to Ag-coated porous silicon membranes (Ag-pSi) | 4-Mercaptobenzoic acid (4-MBA) EF 107 | no |
