Fabrication of AuNRs-PDMS Micropillar Structure and Its Label-free SERS Detection for Regulated Living Cells

In this work, gold nanorods-polydimethylsiloxane(AuNRs-PDMS) micropillar was proposed, of which topographic feature could serve as mechanical cues for cell regulation, as well as AuNRs assembly on the micropillar could serve as surface-enhanced Raman scattering(SERS) substrates for regulated cell detection. Three fabrication routes, including solvent evaporation, absorption transferring and stamp transferring, were compared and optimized towards the construction of AuNRs-PDMS micropillar with high SERS enhancement and homogeneity. The SERS performance was determined by comparing the spectra changes of 4-mercaptobenzoic acid(4-MBA) at different test points on AuNRs-PDMS micropillar. Results demonstrate that AuNRs-PDMS micropillar by stamp transferring possesses acceptable SERS enhancement with the highest homogeneity, and the relative standard deviation(RSD) of SERS intensity is 7.3%, indicating the structure is a feasible SERS substrate for label-free cell detection. Mesenchy & hybull; mal stem cells(MSCs), the object for cell regulation and SERS detection, were cultured on the AuNRs-PDMS micropillar by stamp transferring and AuNRs-PDMS flat control. Compared to their counterparts, MSCs regulated by the AuNRs-PDMS micropillar show growth direction along the topographic feature and morphology changes. Meanwhile, the variation of SERS spectra illustrates the increase of lipids and the changes of protein components as well as bond stretching vibrations during cell regulation, implying that the contact guidance and morphology changes of regulated cells are associated with cell component variations. The strategy builds a bridge between cell regulation and label-free SERS detection of the regulated cells, providing deeper insight into cell-substrate interactions.