| Nanomaterials have unique physical and chemical properties that make them a premium material for the fabrication of new optical nano-probes.Since the properties of nanomaterials are highly dependent on their regulatable size and shape,when combined with specific signal transduction mechanism components,nanomaterial-based sensors can significantly increase the sensitivity and specificity of analyte detection.The main research contents of this topic are summarized as follows:(1)Since the anti-tumor drug has disadvantages such as hydrophobicity and instability,the use of the nano-carrier improves the hydrophobicity of the drug and promotes drug delivery and cell uptake.Here,we constructed a multifunctional spherical nucleic acid nano-micelle drug delivery system with high drug delivery rate and therapeutic effect.Firstly,the separation efficiency of paclitaxel-nucleic acid(PTX-DNA)complexes were effectively improved by magnetic separation technique using auxiliary material magnetic beads-gold nanoparticles(MB-AuNPs).Next,the PTX-DNA amphiphilic monomer was synthesized by utilizing the hydrophilicity of DNA as the hydrophobic end and the hydrophobicity of PTX as the hydrophobic end.The PTX-DNA monomer and the PTX-DNA/FAM monomer were self-assembled to form spherical nano-micelle.And spherical nanomaterials were more susceptible to phagocytosis by cells than other shaped materials.The hydrophobic PTX was linked to the DNA using a bioreductive activated disulfide,and when the nano-micelle was taken up by the cells,PTX was freely released in the presence of glutathione(GSH).The separation time of each step was only 60 s,which greatly shortened the synthesis time of materials and avoided the disadvantages of time-consuming and labor-intensive.Cellular uptake and drug release of PTX-DNA nano-micelles were demonstrated by fluorescence microscopy and flow cytometry.The synthesized nano-micelles have better hydrophilicity,better biocompatibility,higher stability,monodisperse size and higher therapeutic potential.We believe that this method has significant research potential in clinical research applications.(2)Circulating tumor cells(CTCs)refer to tumor cells that enter the peripheral blood during spontaneous or medical treatment and have high vitality and metastatic potential.Therefore,the detection of CTCs is of great significance for the clinical diagnosis,prognosis and detection of early tumor metastasis.The integration of different nanostructures on the substrate and the modification of corresponding specific recognition molecules have become the most common method for efficient capture of CTCs from whole blood samples.Rough nano-interfaces have the increasing the specific surface area to connect more aptamer and improve the capture efficiency of CTCs;however,the rough interface can cause non-specific cell adhesion to increase,leading to false Positive.Therefore,the adhesion of non-target cells could be reduced by using anti-contaminant molecules.Modification of polyethylene glycol(PEG)molecules on "soft" substrates can effectively improve hydrophilicity while controlling non-specific cell adhesion.Here,we designed a highly efficient and non-invasive release of CTCs based on anti-pollution material PEG.On the one hand,the virtual PEG template used in the platform improved the biocompatibility of the interface and effectively controlled the non-specific cell adhesion;on the other hand,the gold nanoflower substrate had a rough specific surface area and significantly enhanced the connection efficiency of aptamer to increase the capture efficiency of CTCs.At the gold nanoflower substrate,functionalization with DNA aptamer showed excellent capture specificity and sensitivity to target cells.Compared with other nanostructures,the gold nanoflower substrate could effectively increase the capture performance of target cells at low cell density.By culturing the released CTCs,cell viability and proliferation were normal.This work provided a strategy for efficient capture and non-invasive release of small amounts of CTCs,and we believe it has great potential for clinical validation.(3)The prevalence of CTCs in peripheral blood is extremely low,containing1-10 CTCs/mL in 10 million white blood cells and 5 billion red blood cells,so high specificity for detecting CTCs in a large number of normal cells has great challenges.Based on the unique properties of noble metal nanoparticles,surface-enhanced Raman scattering(SERS)can greatly exploit the spectral signals of individual molecules,and in many areas can even provide detection limits for single molecules.Therefore,SERS-based detection methods can provide powerful analytical tools for CTCs to detect multiple strategies.Here,we developed a multi-Raman signal enhancementmechanism based on gold nanostars(AuNSs)and hybrid chain reaction(HCR),as well as a dual recognition mechanism for DNA aptamer and anti-EpCAM(AE),highly sensitive detection and high specific recognition of CTCs.By constructing a signal probe: functionalizing the PEG molecule on the surface of the AuNS,it had higher stability and reduced non-specific capture and uptake while providing an amino group for subsequent ligation of the strand DNA and AE.Among them,HCR was generated by initiating the strand DNA to initiate the hairpin H1 and the hairpin H2 of the modified ROX,and a strong SERS signal was generated.Since AE specifically recognized epithelial cell adhesion molecules on the surface of CTCs,it had high sensitivity.When the CTCs were double-recognized by modifying the aptamer on the gold nanoflower substrate and the AE on the signal probe,the high specificity of cell capture in complex whole blood samples was greatly enhanced.Thereafter,the aptamer complementary strand was hybridized with the aptamer DNA to effect the release of CTCs modified with HCR/AE/PEG/AuNS.Under optimal release conditions,complete release and collection of CTCs could be achieved to detect Raman signals.It had good linearity in the range of 1 to 100 cells/mL and the detection limit reached 1 cell/mL. |
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