Novel SERS Nanoprobes For Measurement Of Caspase-3 And CN~-in Living Cells

In recent years,Surface-enhanced Raman scattering(SERS)has become a mature vibrational spectroscopic technique and the number of applications in the chemical,optical,and in particular life sciences is rapidly increasing.SERS can provide positive identification of an analyte or an analyte mixture with high sensitivity and selectivity.As newly emerging optical nanoprobes,SERS tags have been synthesized by combining different types of metal nanomaterials,organic Raman reporters,and functional moieties.There has been a considerable amount of research on developing SERS tags for either molecular multiplexed detection or bioimaging at the level of microorganisms,cells,tissues,and living animals.SERS research is a truly multi-disciplinary field that has benefited from dynamic interactions among chemists,physicists and engineers.New and exciting developments presented herein show a bright future for the widespread adoption of SERS and will facilitate the transition of SERS from research laboratories to real-world diagnostics,biomedical sensing,and field applications.This paper explains two different types of SERS probes for detection target molecule.(1)Alkyne-based ratiometric Surface-Enhanced Raman Scattering nanosensor for imaging caspase-3 in living cells and tissuesHere designed an alkyne-based SERS nanoprobe for the detection of caspase-3 in living cells and tissues with high sensitivity and good signal reproducibility.By making full use of the anti-interference ability of alkyne groups in the cellular silent region(1800-2800 cm-1),different alkynyl molecules were selected as Raman reporters and used to label the target peptide chains,respectively,and self-assembled with GNRs(gold nanorods)to build unique ratiometric nanoprobe.The Raman signal of molecular 3-(4-(phenylethynyl)benzylthio)propanoic acid(PEB)on the peptide chain specifically recognized by caspase-3 is decreased at 2218 cm-1,while the unrecognized alkynyl molecule 4-thiol phenylacetylene(TPA),at 2027 cm-1,does not change,thereby allowing the quantitative detection of caspase-3 based on the ratiometric peak intensity of I2027/I2218.(2)GO(grapheme oxiide)-based new SERS composite nanoprobe for the detection of CN-Here,we have developed a one-pot strategy for synthesizing ternary reduced graphene oxide-Hemin-Au(rGO-H-Au)nanohybrids by simply heating GO,hemin and metal precursors under alkaline conditions,without adding any additional surfactant,stabilizing agent and reducing agents.As we all know,the SERS enhancement effect of silver is much higher than that of gold.However,the stability is poor.Therefore,on the basis of the synthesis of H-rGO-Au,silver is coated on gold,and then gold is coated on silver.Finally,our SERS nanoprobe H-rGO-Au-Ag-Au is used for detection CN-,and can have a good response to achieve quantitative detection of CN~-.