SERS‐Enabled Lab‐on‐a‐Chip Systems

Abstract

REVIEWnanoparticle array with fi xed nanogaps on solid-state substrates. [ 8 ] Cross-contamination and channel clogging could be avoided in microfl uidic chips equipped with solid-state SERS substrates that will not fl ow with analytes. [ 15 ] On this basis, implanting solid-state SERS substrates within microfl uidic devices could enable SERS-independent functions in SERSenabled LoC systems, such as microfl uidic chemical reactors. [ 16 ] On the other hand, LoC systems could serve as an integrated platform to make SERS detection more reproducible, effi cient, safe, and environmentally friendly. For example, recent microfl uidic reversible manipulations have allowed controllable colloid aggregation in microfl uidic channels. [ 17 ] More importantly, dynamic molecule trapping in microfl uidic devices could address the uneven distribution of analytes (e.g., the coffeering effect) on solid-state SERS substrates. [ 18 ] Furthermore, the fl exible integration of SERS substrates with microfl uidic chips would contribute to the commercialization of portable SERS chips.The combination of microfl uidics with SERS not only provides new opportunities for both techniques as outlined above, but also paves the way for multifunctional SERS-enabled LoC systems beyond SERS detection, which is often overlooked by both communities. In this review, we will bridge this gap by discussing the recent advancements in both SERS-enabled LoC systems and reproducible SERS substrates, as well as their complementary combination. For a better understanding of the fundamental role of SERS substrates in SERS-enabled LoC systems, the fundamentals of SERS will be briefl y described in Section 2. Section 3 will discuss technical progress with respect to the fabrication of multifunctional SERS-enabled microfl uidic devices, including reproducible SERS substrates and microfl uidic dynamic trapping methods. Applications of SERS-enabled LoC systems in chemical and biological detection, as well as the commercial perspective of portable SERS devices, will be discussed in Section 4. Finally, in Section 5, we will conclude with current challenges and offer an outlook on multifunctional SERS-enabled LoC systems.

A SERS microfluidic platform for targeting multiple soluble immune checkpoints

“…Surface-enhanced Raman scattering (SERS) is an excellent readout technique for detecting biomolecules, and have gained wide attention as an alternative to fluorescence based immune-platform due to its multiplexing capability and photostability (Huang et al 2015a;Laing et al 2016;Luo et al 2014;Qian and Nie 2008;Wang et al 2017). However, the major limitations of SERS based immune-platform are the less antibody-target interaction due to the slow diffusion of SERS nanoparticles and the high level of nonspecific attachment of biomolecules towards the sensor surface.…”

Two-photon reduction: a cost-effective method for fabrication of functional metallic nanostructures

“…Microfluidic chips or LoC systems are widely used in synthesis, analysis, detection, sensing and therapy in various field such as biology, chemistry, physics, material science, pharmaceuticals because of its integrated multifunctional system. [79,105] When SERS is combined with LoC, a sensitive system can be created for optofluidic detection. Integration of solid-state SERS substrate with microfluidic devices (Figure 13 (a-d)) could be realized through two different methods.…”

Review of optical fibre probes for enhanced Raman sensing

“…[184][185][186] Optode-integrated microfluidic chip as Raman probe Throughout the previous decade, the integration of miniaturized optical systems into microfluidic chips has been aimed at increasing the sensitivity of in-situ detection technologies. [187] The optofluidic microsystem offers several advantages, as follows: highly localized and multiplexed detection is enabled on-chip; split type infrastructure makes exchange of chips and sensors more convenient; and the modular nature of the optode and chip integration enables the use of either portable spectrometers or high-performance microscopes. Several examples of microfluidic devices incorporating SERS detection have been presented.…”