Large‐Scale, Ultrasensitive, Highly Reproducible and Reusable Smart SERS Platform Based on PNIPAm‐Grafted Gold Grating

Abstract

A smart plasmonic sensor based on periodic gold gratings grafted with poly(N‐isopropyl acrylamide) (PNIPAm) has been designed and realized. A periodic gold structure was created on the polymer backing with an excimer laser (1×2 cm2 modified area) and was subsequently covered by thin gold film. In the next step, a 7 nm thick PNIPAm layer was grafted to the gold surface through a two‐step procedure: covalent attachment of 4‐carboxybenzil groups followed by carboxyl groups activation and their coupling with amino‐terminated PNIPAm. Surface properties of the prepared structure and their switchable behavior were investigated using refractometry, wettability measurements, AFM in water, cyclic voltammetry, and pH‐ and temperature‐dependent Z‐potential measurements. The structure enables effective entrapment and SERS detection of azo dyes, significant reduction of minimal detectable concentration of target molecules, and a detection limit down to femtomolar concentrations. Excitation of plasmons on the well‐ordered surface structure also gives excellent reproducibility for SERS along the particular sample surface and as well as on different samples. Additionally, the reversible switching of wettability under repeated temperature changes on the gold plasmonic platform allows multiple uses of the developed system.

Lipophilic Gold Grating for SERS Detection of Biological Objects

“…Prepared gold gratings were chosen as a substrate for plasmonic sensor fabrication due to homogeneous response and strong signal enhancement, as was described before [5]. The surface of the gold was modified by a range of arenediazonium tosylates (ADTs): ADT-CH3, ADT-C4H9, ADT-C10H21 and ADT-C16H33 in order to improve affinity with lipophilic biological compounds ( Figure 1).…”

Repeated Temperature and Humidity Stability of SERS-active Periodical Silver Nanostructure

“…Silver grating preparation Silver gratings were prepared according to previously published procedure [3]. First, the thin layer of Su-8 (Microchem) was deposited on the glass substrate by spin-coating method.…”

“…It must be also noted, that the prepared silver gratings were chosen as a substrate for SERS sensor fabrication due to homogeneous response and strong signal enhancement, as was described before [3]. So, the evaluation of SRRS results were performed from the point of absolute SERS signal intensity and the homogeneity of SRS signal.…”

Highly Sensitive Temperature‐responsive Sensor Based on PS‐PDEA‐PS/C60‐MWCNTs for Reversible Switch Detection of Catechol

“…Hence, PS and PDEA block together, which can form a stable core‐shell macromolecule with temperature‐sensitive properties. The temperature‐sensitive polymers undergo phase transitions with environments above or below their critical solution temperature (LCST) .…”

“…Hence, PS and PDEA block together, which can form a stable core-shell macromolecule with temperature-sensitive properties. The 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 temperature-sensitive polymers undergo phase transitions with environments above or below their critical solution temperature (LCST) [20][21][22].…”