Plasmon-enhanced Raman Spectroscopy In Biological Analysis Based On Multiphase Assembled Structures

The applications of photoactive semiconductor-metal heterojunction are mostly in the field of photocatalysis and optoelectronic devices.There are few studies on its application in enhanced Raman spectra,especially in Raman bioanalysis.On the other hand,the dynamic regulation of the coupling between metal nanoparticles on the nanoscale is based on dynamic DNA nanotechnology in equilibrium,which has limitations in obtaining dynamic and responsive materials with autonomous behavior We took advantage of photoactive semiconductors to construct enhanced Raman detection substrates based on semiconductor-metal heterostructure realizing its application in bioanalysis.We also achieved autonomously regulating the life of plasmonic metamolecules(PMs),which were assembled based on DNA origami in the non-equilibrium system,and initially explored its application in enhanced Raman analysis.1.We took advantage of photoactive semiconductor titanium dioxide(TiO2)and relied on the molecular recognition ability of the aptamers and the high affinity of the aptamers with the analytes to trigger the Raman-labeled gold nanoparticles(AuNPs)probes to combine with the photoactive TiO2@Ag substrate,forming a sandwich structure.When the substrate was pre-irradiated with ultraviolet light,it resulted in photo-induced enhanced Raman spectroscopy(PIERS)whose enhancement was higher than surface enhanced Raman spectroscopy(SERS).The detection platform can serve as a versatile detection platform for sensitively analyzing various biomolecules including small molecules(ATP,limit of detection(LOD)of 0.1 nM),a biomarker(thrombin,LOD of 50 pM),and a drug(cocaine,LOD of 5 nM).This strategy based on aptamer recognition sheds new light on Raman analysis and detection of small molecules.2.We reported perovskite enhanced Raman scattering(PervERS)substrate,in which efficient photo-induced interfacial charge transfer enabled remarkable Raman enhancement.Under simultaneous continuous irradiation of ambient light and Raman laser,the PervERS substrate reached a Raman enhancement factor of 8.8 ×106 and enables trace molecular detection down to 10-9 M.Furthermore,the photo-induced chemical enhancement endowed the PervERS substrate superior enhancement uniformity that can even endure multiple bending operations.Our results may provide important insights into the development of stable and highly sensitive semiconductor SERS technology3.We designed a tetrahedral DNA origami with arm length?66 nm,and extended 7 capture strands on different arms to capture gold nanorods(AuNRs)forming 11 kinds of PMs.Among them,the PMs of LH-R3(x1,x2,x4)and RH-R3(x2,x4,x5)were chiral isomers,in which AuNRs were coupled to each other,resulting in the change of the surface charge distribution.Furthermore,we labelled AuNRs at the arm x2 with 4-MBA and found that the Raman intensity of LH-R3(x1,x2,x4)was enhanced?3.6 times,compared to the same concentration of R1(x2).With the use of probe molecules with higher scattering cross section,the plasmon-enhanced Raman substrate is expected to be used for cell imaging4.We constructed a pair of proton-responsive chiral plasmonic metamolecules(CPMs)of L-R3(x1,x2,x4)and R-R3(x2,x4,x5)by introducing triplex DNA segments on the tetrahedral DNA origami arms.In the non-equilibrium system,we realized the autonomous reconfiguration of the metamolecules by coupling with the proton-controlled chemical reaction network(CRN).By controlling proton concentration changing kinetics of the CRN,the lifetime of the CPMs were controlled autonomously Our work of dynamic autonomous reconfiguration of plasmon effect provides a new strategy for enhanced Raman dynamic design.