SERS Imaging Research Articles

Dual-purpose nanoparticle assembly for identifying preferential intracellular targets of oxindolimine copper(II) complexes through SERS imaging

In this study, the main goal was to identify the intracellular targets of oxindolimine copper(II) complexes by SERS and Raman imaging of living HeLa cells, whose action as a cancer inhibitor has been previously determined. The used SERS probe was constituted of spherical gold nanoparticles together with the Raman reporter 5,5′-dithiobis-2-nitrobenzoic acid (DTNB) and oxindolimine copper(II) complexes, [Cu(isatp)Cl] and [Cu(nisatp)H2O]. Two excitation radiations were used to acquire living single HeLa cells images: 532 nm to acquire the conventional Raman information of the cells and 785 nm to acquire the localization of the modified SERS probe inside the cells. The Raman images of the main intracellular components were obtained by multivariate analysis, and the SERS images were obtained by univariate analysis using a Raman reporter. The SERS and Raman images showed that the complexes could enter the cells together with the gold nanoparticles, causing main damage to the nuclei and lipids-rich region. In addition, there was no evidence of water entry into the cell.

DNA walker-powered SERS logic aptasensors for accurate imaging and identification of tumor cells

Identification of tumor cells is of vital importance for accurate diagnosis and treatment of tumors. Herein, DNA walker-powered SERS logic aptasensors were proposed for accurately identifying tumor cells by high-sensitively and specifically SERS imaging membrane proteins on single live cells. The SERS logic aptasensors consist of gold nanoparticles (AuNPs)-based Logic probes (LPs), Network probes (NPs) and EpCAM probes (EPs). As a proof-of-principle, the cells highly-expressed single EpCAM proteins, single MUC1 proteins, and both or neither the two proteins were tested respectively, and the SERS logic aptasensors can perform AND Boolean logic analysis by EpCAM-triggered DNA walker-powered assembly of AuNP network nanostructures (AuNNs) on cell membrane. By imaging SERS signals of single DTNB, single 4-MBA, simultaneous signals (4-MBA, 2-MBT and DTNB), or none, respectively, the cells with or without the high-expression of EpCAM and/or MUC1 proteins can be accurately and logically identified. Furthermore, the aptasensors were expanded to image the EpCAM and HER2 proteins on cells for accurately identifying the subtypes of breast cancer cells. The SERS logic aptasensors can achieve accurate identification and logic analysis of cancer cell classification and subtypes, and have broad potential applications in accurate diagnosis and treatment of tumors.

Ratiometric SERS imaging for indication of peroxynitrite fluctuations in diabetic wound healing process

Peroxynitrite (ONOO−) involves in diabetic wounds and its concentration is fluctuated in different pathological stages during the wound healing process. Thus, ONOO− may be utilized as a powerful biomarker to indicate the healing process of diabetic wound. However, the pathological roles of ONOO− can’t be fully understood yet. Herein, inspired by the mechanism that phenylboronic pinacol ester can react with ONOO− specifically, we report a new kind of SERS nanoprobes to monitor ONOO− fluctuation during diabetic wound healing process. The gold-silver (Au@Ag) core-ultrathin shell nanoparticles were utilized as active substrate and conjugated with phenylboronic pinacol ester molecules on the surface of Ag shell to simultaneously act as Raman reporter molecules and recognition moiety of ONOO−. In addition, functional polyethylene glycol (HS-PEG) and bovine serum albumin layers were sequentially immobilized on the surface of Ag shell to improve the stability of the nanoprobes. In the presence of ONOO−, phenylboronic pinacol ester could be converted into the corresponding phenol, inducing the SERS signal changes. The concentration fluctuation of ONOO− could be quantitatively detected through the SERS signal intensity ratio (1076 cm−1/998 cm−1) changes of typical peaks. The nanoprobes exhibited a wide response range from 0 to 75 μM with 0.12 μM as the detection limit. In the diabetic wound skin models, ONOO− concentration fluctuations during the wound healing process before and after drug treatment could be obtained by SERS imaging. We expect the proposed SERS imaging assay could be a noninvasive and powerful tool to monitor the diabetic wound healing.

A clinically feasible diagnostic spectro-histology built on SERS-nanotags for multiplex detection and grading of breast cancer biomarkers

Simultaneous detection of multiple biomarkers is always an obstacle in immunohistochemical (IHC) analysis. Herein, a straightforward spectroscopy-driven histopathologic approach has emerged as a paradigm of Raman-label (RL) nanoparticle probes for multiplex recognition of pertinent biomarkers in heterogeneous breast cancer. The nanoprobes are constructed by sequential incorporation of signature RL and target specific antibodies on gold nanoparticles, which are coined as Raman-Label surface enhanced Raman scattering (RL-SERS)-nanotags to evaluate simultaneous recognition of clinically relevant breast cancer biomarkers i.e., estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor2 (HER2). As a foot-step assessment, breast cancer cell lines having varied expression levels of the triple biomarkers are investigated. Subsequently, the optimized detection strategy using RL-SERS-nanotags is subjected to clinically confirmed, retrospective formalin-fixed paraffin embedded (FFPE) breast cancer tissue samples to fish out the quick response of singleplex, duplex as well as triplex biomarkers in a single tissue specimen by adopting a ratiometric signature RL-SERS analysis which enabled to minimize the false negative and positive results. Significantly, sensitivity and specificity of 95% and 92% for singleplex, 88% and 85% for duplex, and 75% and 67% for triplex biomarker has been achieved by assessing specific Raman fingerprints of the respective SERS-tags. Furthermore, a semi-quantitative evaluation of HER2 grading between 4+/2+/1+ tissue samples was also achieved by the Raman intensity profiling of the SERS-tag, which is fully in agreement with the expensive fluorescent in situ hybridization analysis. Additionally, the practical diagnostic applicability of RL-SERS-tags has been achieved by large area SERS imaging of areas covering 0.5–5 mm2 within 45 min. These findings unveil an accurate, inexpensive and multiplex diagnostic modality envisaging large-scale multi-centric clinical validation.

Simultaneous Visualization of Dual Intercellular Signal Transductions via SERS Imaging of Membrane Proteins Dimerization on Single Cells.

The visualization of protein dimerization on live cells is an urgent need and of vital importance for facile monitoring the signal transduction during intercellular communication. Herein, a highly sensitive and specific SERS strategy for simultaneously imaging dual homodimerizations of membrane proteins on single live cells was proposed by networking of AuNPs-based dual-recognition probes (dual-RPs) and SERS tags via proximity ligation-assisted catalytic hairpin assembly (CHA). The dual-RPs were prepared by comodifying hairpin-structured ssDNAs H1-Met and H1-TβRII on 50 nm AuNPs and two SERS tags for membrane proteins Met and TβRII were prepared respectively by labeling their corresponding Raman molecules and hairpin-structured single-stranded DNAs H2-Met or H2-TβRII on 15 nm AuNPs. The membrane proteins were ligated proximally by specific aptamers, and the dimerizations of proteins resulted in the proximity ligation-assisted CHA-based networking of dual-RPs and SERS tags to form 15Au-50Au network nanostructures with significantly enhanced SERS effect. The SERS strategy for visualizing the membrane protein dimerization was established and the good performance on simultaneously SERS imaging dual dimerizations of membrane proteins (i.e., Met-Met and TβRII-TβRII) was confirmed. Furthermore, the membrane protein dimerization-based signaling pathways between cancer cells and stromal cells or stem cells were observed by SERS, which indicates that the proposed SERS strategy is a good method for high-sensitivity monitoring of membrane proteins dimerizations-based multiple intercellular signal transductions in a natural and complex cellular microenvironment.

Linezolid nanoAntiobiotics and SERS-nanoTags based on polymeric cyclodextrin bimetallic core-shell nanoarchitectures

We describe a mild, ecofriendly, and straightforward two-step strategy for making core-shell Au@Ag bimetallic nanoparticles (BMNPs) for antibacterial nanomedicine and SERS imaging. The synthesis exploits the unique properties of the cationic polymeric cyclodextrin (PolyCD) as both reducing and stabilizing agent to obtain, monodispersed and stable Au@Ag BMNPs. PolyCD-driven protocol includes the synthesis of PolyCD-coated Au monometallic nanoparticles (MNPs) as a seed material for the subsequent growing of a silver shell. PolyCD was produced by polymerization of the azido modified βCD monomers with epichlorohydrin and subsequent reduction of azido derivative. The amino groups, as hydrochloride salts (one for CD ring), are pivotal for the formation of BMNPs in mild conditions. Nanoantibiotics and SERS-nanoTag were prepared by complexation of Au@Ag BMNPs with Linezolid (Lz) and 4-mercaptophenyl boronic acid, respectively. Au@Ag@Lz complexes showed a good antibacterial activity against all tested microorganisms including the methicillin resistant Staphylococcus aureus (MRSA).

DNA-Au Janus Nanoparticles for In Situ SERS Detection and Targeted Chemo-photodynamic Synergistic Therapy.

Cancer theranostics is of great significance in the personalized therapy. In this work, stable Janus nanoparticles (JNPs) containing PEG and two kinds of DNAs were prepared by means of "click chemistry". In response to ATP or acid condition, the prepared JNPs could form Au NP dimers, which facilitate in situ SERS detection and SERS imaging analysis of cancer cells due to the formation of "hot spots" in the nanogap between the Au NP dimers. A detection limit of 2.3 × 10-9 M was obtained for ATP. As for a pH sensor, the SERS signals increased with the decrease of pH value from 8.0 to 4.0. In situ monitoring of ATP or acid condition in cancer cells by SERS can improve the accuracy and sensitivity of diagnosis. Moreover, drugs and photosensitizers loaded on the other side of JNPs led to the chemotherapy/photodynamic therapy synergistic antitumor effect, which was verified by in vitro and in vivo experiments. Given the excellent performance in SERS detection and cancer therapy, the developed JNPs hold considerable potential in cancer theranostics.

Microporous Multiresonant Plasmonic Meshes by Hierarchical Micro-Nanoimprinting for Bio-Interfaced SERS Imaging and Nonlinear Nano-Optics.

Microporous mesh plasmonic devices have the potential to combine the biocompatibility of microporous polymeric meshes with the capabilities of plasmonic nanostructures to enhance nanoscale light-matter interactions for bio-interfaced optical sensing and actuation. However, scalable integration of dense and uniformly structured plasmonic hotspot arrays with microporous polymeric meshes remains challenging due to the processing incompatibility of conventional nanofabrication methods with flexible microporous substrates. Here, scalable nanofabrication of microporous multiresonant plasmonic meshes (MMPMs) is achieved via a hierarchical micro-/nanoimprint lithography approach using dissolvable polymeric templates. It is demonstrated that MMPMs can serve as broadband nonlinear nanoplasmonic devices to generate second-harmonic generation, third-harmonic generation, and upconversion photoluminescence signals with multiresonant plasmonic enhancement under fs pulse excitation. Moreover, MMPMs are employed and explored as bio-interfaced surface-enhanced Raman spectroscopy mesh sensors to enable in situ spatiotemporal molecular profiling of bacterial biofilm activity. Microporous mesh plasmonic devices open exciting avenues for bio-interfaced optical sensing and actuation applications, such as inflammation-free epidermal sensors in conformal contact with skin, combined tissue-engineering and biosensing scaffolds for in vitro 3D cell culture models, and minimally invasive implantable probes for long-term disease diagnostics and therapeutics.

O-GlcNAcylation mapping of single living cells by in situ quantitative SERS imaging

O-GlcNAcylation is involved in many biological processes including cancerization. Nevertheless, its in situ quantification in single living cells is still a bottleneck. Here we develop a quantitative SERS imaging strategy for mapping the O-GlcNAcylation distribution of single living cells. O-GlcNAcylated compounds (OGCs) can be quantified through their in situ azide labeling and then a click reaction competing with azide and Raman reporter labeled 15 nm-gold nanoparticles (AuNPs) for linking to dibenzocyclooctyne labeled 40 nm-AuNPs to produce OGC-negatively correlated SERS signals. The calibration curve obtained in vitro can be conveniently used for detecting OGCs in different areas of single living cells due to the negligible effect of cell medium on the click linkage and Raman signal. This method has been successfully applied in mapping O-GlcNAcylation distribution in different cell lines and monitoring O-GlcNAcylation variation during cell cycling, which demonstrate its great practicability and expansibility in glycosylation related analysis.

Improving SERS bioimaging of subcutaneous phantom in vivo with optical clearing.

Surface-enhanced Raman scattering (SERS) has proven to be a promising technique for different types of imaging including preoperative and intraoperative in vivo tumor visualization. However, the strong scattering of the turbid tissue limits its use in subcutaneous areas. In this article, we used an optical clearing technique to improve the SERS signal from a subcutaneous tumor phantom. The phantom is a 2 mm sphere of calcium alginate with incorporated petal-like gap-enhanced Raman tags. The use of optical clearing increases the SERS signal target-to-background ratio for 5 times and allow to decrease the total imaging time for at least 10 times. In addition, SERS imaging assisted with optical clearing made it possible to more precisely determine the shape and boundaries of the implanted phantom. The combination of optical clearing and SERS is a promising strategy for the clinical imaging of subcutaneous objects that are usually shielded by dermal tissue.

Spatially resolved determination of the abundance of the HER2 marker in microscopic breast tumors using targeted SERS imaging.

Highly selective nanoprobes have been developed based on SERS-active Au@Ag nanoparticles protected by a PEG coating and functionalized with monoclonal antibodies against human epidermal growth factor receptor 2 (HER2). The PEG coating allows to drastically reduce unspecific interactions during incubation on tissues, while the monoclonal antibodies allow a highly specific targeting of HER2. Using the designed SERS nanoprobes combined with a spectral imaging and data weighting approach, we demonstrate the proportionality between the SERS signal and the amount of HER2 antigen on the cell membranes as measured by digital image analysis of IHC staining in microscopic breast tumors (linear fit R2 = 0.87). We also show that the level of expression of HER2 measured by SERS is significantly different between several microscopic tumor parts of the same tissue slide. Therefore, SERS is proving to be a suitable technique for the localized quantitative measurement of specific markers in breast cancerous tissues. Owing to its high multiplexing capabilities, SERS could be a future tool of choice for characterizing the molecular heterogeneity of tumors at the microscopic scale.

Theoretical Study on Symmetry-Broken Plasmonic Optical Tweezers for Heterogeneous Noble-Metal-Based Nano-Bowtie Antennas.

Plasmonic optical tweezers with a symmetry-tunable potential well were investigated based on a heterogeneous model of nano-bowtie antennas made of different noble substances. The typical noble metals Au and Ag are considered as plasmonic supporters for excitation of hybrid plasmonic modes in bowtie dimers. It is proposed that the plasmonic optical trapping force around a quantum dot exhibits symmetry-broken characteristics and becomes increasingly asymmetrical with increasing applied laser electric field. Here, it is explained by the dominant plasmon hybridization of the heterogeneous Au–Ag dimer, in which the plasmon excitations can be inconsistently modified by tuning the applied laser electric field. In the spectrum regime, the wavelength-dependent plasmonic trapping potential exhibits a two-peak structure for the heterogeneous Au–Ag bowtie dimer compared to a single-peak trapping potential of the Au–Au bowtie dimer. In addition, we comprehensively investigated the influence of structural parameter variables on the plasmonic potential well generated from the heterogeneous noble nano-bowtie antenna with respect to the bowtie edge length, edge/tip rounding, bowtie gap, and nanosphere size. This work could be helpful in improving our understanding of wavelength and laser field tunable asymmetric nano-tweezers for flexible and non-uniform nano-trapping applications of particle-sorting, plasmon coloring, SERS imaging, and quantum dot lighting.

SERS imaging analyses of bacteria cells among plant tissues

A chemical imaging method to mass surveil bacteria cells among plant tissues in situ is reported. Bacteria cells were pre-labeled with 3-mercaptophenylboronic acid for complexation with gold nanoparticles. Surface-enhanced Raman spectra were collated en masse to generate panoramic chemical images of bacteria populations. The approach was successfully employed to study the distribution of mass bacteria populations directly on and in selected plant tissues. This study demonstrates the great potential with which SERS imaging can be utilized for the study of bacterial cells among complex matrices, in some ways that are superior to electron and fluorescent microscopies.

Accurate quantitative detection of cell surface sialic acids with a background-free SERS probe

Sialic acid (SA) is a special monosaccharide widely distributed at the termini of sugar chains on the cell surface, and its expression level is closely connected with various biological and pathological processes. Therefore, accurate quantitative detection of SA on cancer cell surface is of great significance for clinical diagnosis and therapy. Here, we developed a whole-surface accessible method of accurate SERS quantification of SA level on a single cell, in which silver nanoparticles functionalized with 4-mercaptophenylboric acid and 4-mercaptobenzenitrile was used as the background-free SERS probe. The cyano group on the nanoprobe showed a unique Raman shift at 2232 cm−1, where most of the biological samples have no Raman response. Meanwhile, the boronic acid group had high specificity to SA molecules at physiological pH. The expression level of SA can be accurately quantitated on the basis of the CN Raman signal. The average number of expressed SA molecules on the surface of a single HeLa cell was 4.6 × 107. And SERS imaging of a single cell was achieved at 2232 cm−1 without biological interference. We evaluated SA expression level on the surface of different cancer cells and dynamically monitored SA expression under the influence of drugs. The proposed approach is accurate as well as sensitive for background-free quantification of SA on cell surface, which is promising for revealing the relationship between tumors and cell surface glycosylation.

Preparation of Aptamer-functionalized Au@pNTP@SiO2 Core-Shell Surface-enhanced Raman Scattering Probes for Raman Imaging Study of Adhesive Tape Transferred-Latent Fingerprints

Abstract The core-shell SERS nanoprobe combined with adhesive tape was used to recognize the latent fingerprints on the surface of the object, which provides an effective solution for the imaging of latent fingerprints on the surface of large immobile or curved objects. First, the Au@pNTP@SiO2 SERS probes modified by aptamers specific to lysozyme were prepared, and characterized by TEM/EDS, and its SERS effects were also tested. Then the probe was incubated with the aged-latent fingerprints on the surface of different objects. Afterwards, the dried latent fingerprint with modified SERS probes was transferred to the adhesive tape and imaged under the confocal Raman microscope. The results showed that the size distribution of the core-shell SERS probe was uniform, which was mostly concentrated in 60 nm, leading to excellent stability and dispersity. The SERS probe also had strong SERS intensity and reproducibility with the characteristic peaks at 723, 855, 1081, 1343 and 1572 cm−1, which were consistent with the previous reports. When applying such SERS probe into the tape-transferred latent fingerprint's imaging, not only the primary structure (pattern) but also the secondary structure (forking and ring points) and the third-level structure of fingerprint (sweat pore) could be clearly observed. The successful development of the SERS imaging of transferred latent fingerprint on adhesive tapes combined with the aptamer-functionalized SERS probe provides an effective method for recognizing latent fingerprints in forensic science, which also has the potential applications in the other areas such as food safety and public safety testing.

Cell-Penetrating Peptide Conjugated SERS Nanosensor for in Situ Intracellular pH Imaging of Single Living Cells during Cell Cycle.

Intracellular pH is an important modulator of cell functions, and its subtle change may dramatically affect the cellular activities and cause diseases. A reliable imaging of the intracellular pH is still a great challenge. We imaged the intracellular pH during the cell cycle at the single living cell level using newly designed cell-penetrating peptide conjugated pH nanosensors on a home-built in situ microscopic cell culture platform. The conjugated cell-penetrating peptide greatly enhanced the uptake of nanosensors without sacrificing the pH response. We observed a gradual alkalization from interphase to prophase and rapid acidification from prometaphase to telophase, reflecting variation and consumption of the species related to the energy storage during cell cycle. We realized SERS-based pH and fluorescence dual-mode imaging when the pH sensor was further modified with fluorescence dye. The integration of SERS imaging with in situ microscopic cell culture system offers great opportunity for revealing the intracellular pH-related biological and pathological processes.

Doping of carbon nanodots for saving cells from silver nanotoxicity: A study on recovering osteogenic differentiation potential

Silver nanoparticles are explored for many advanced biological applications including the development of antimicrobial surfaces on implants, SERS imaging, nanotherapeutics, biosensing and much more. However, recent research findings suggest silver nanoparticles provide blockade of differentiation of mesenchymal stem cells (MSCs), especially into osteogenic developmental pathway via generation of reactive oxygen species. These studies suggest that the application of silver nanoparticles in medical implants should be prohibited. In the current study, carbon nanodots (CND) supported silver clusters (AgC) is explored as a remedy to this problem. The nanostructure was synthesized in microwave irradiation induced rapid method and characterization was conducted via UV–Vis spectroscopy, fluorescence spectroscopy, HRTEM, XRD, FTIR, Raman spectroscopy, DLS, AFM, and XPS. Fluorescence spectrum showed a quantum yield of 0.25 while Raman spectroscopy showed rapid amplification of CND specific peaks implicating significant SERS property. Further in vitro biocompatibility (MTT) and bio-imaging capability was assessed culturing Wharton's Jelly-derived MSCs. In this study, its efficacy as in-situ cellular oxidative stress scavenger is also studied using NBT and DCFH-DA assay. Via ALP assay, alizarin red staining, cell membrane nanoindentation studies, PCR analysis and immunocytochemistry for osteoblast-like gene expression it was confirmed that AgCs can control silver nanoparticle-induced inhibition of osteogenic differentiation in vitro. Thus, AgCs (Carbon nanodots supported silver clusters) are not only considered to be a dual-mode bio-imaging nanoprobe but also a remedy to the silver-induced ROS generation and osteogenic differentiation blockade of MSCs.

Bacteria-induced aggregation of bioorthogonal gold nanoparticles for SERS imaging and enhanced photothermal ablation of Gram-positive bacteria.

The challenge in antimicrobial photothermal therapy (PTT) is to develop strategies for decreasing the damage to cells and increasing the antibacterial efficiency. Herein, we report a novel theranostic strategy based on bacteria-induced gold nanoparticle (GNP) aggregation, in which GNPs in situ aggregated on the bacterial surface via specific targeting of vancomycin and bioorthogonal cycloaddition. Plasmonic coupling between adjacent GNPs exhibited a strong "hot spot" effect, enabling effective surface enhanced Raman scattering (SERS) imaging of bacterial pathogens. More importantly, in situ aggregation of GNPs showed strong NIR adsorption and high photothermal conversion, allowing enhanced photokilling activity against Gram-positive bacteria. In the absence of bacterial strains, GNPs were dispersed and showed a very low photothermal effect, minimizing the side effects towards surrounding healthy tissues. Given the above advantages, the bioorthogonal theranostic strategy developed in this study may find potential applications in treating bacterial infection and even multidrug-resistant bacteria.

Tailored coating of gold nanostars: rational approach to prototype of theranostic device based on SERS and photothermal effects at ultralow irradiance

The last decade has come across an increasing demand for theranostic biocompatible nanodevices possessing the double ability of diagnosis and therapy. In this work, we report the design, synthesis and step-by-step characterization of rationally coated gold nanostars (GNSs) for the SERS imaging and photothermal therapy of HeLa cancer cells. The nanodevices were realized by synthesizing GNSs with a seed growth approach, coating them with a controlled mixture of thiols composed of a Raman reporter and a polyethylene glycol with a terminal amino group, and then reacting these amino groups with folic acid (FA), in order to impart selectivity towards cancer cells which overexpress folate receptors on their membranes. After a complete characterization, we demonstrate that these FA-functionalized GNSs (FA-GNSs) are able to bind selectively to the membranes of HeLa cells, acting as SERS tags and allowing SERS imaging. Moreover, we demonstrate that once bound to HeLa cell membranes, FA-GNSs exhibit photothermal effect which can be exploited to kill the same cells in vitro using laser irradiation in the NIR at a very low and safe irradiance. We thus demonstrate that the FA-GNSs designed following the described approach are an efficient prototype of theranostic nanodevices.

A gold nanoflower-based traceable drug delivery system for intracellular SERS imaging-guided targeted chemo-phototherapy.

Accurate and effective drug delivery in tumor cells significantly improves the curative effect with high drug delivery efficiency, low toxicity and side effects and has become an urgent demand for anticancer therapy. In this paper, a novel traceable and targeted drug delivery nanosystem (i.e. AuNF-nanocarriers) with high drug encapsulation and pH-controlled release was prepared based on gold nanoflowers (AuNFs) for efficient intracellular SERS imaging-guided chemo-phototherapy. SERS-active flower-like gold nanoparticles with large surface area were synthesized first and then modified with Raman and RGD molecules in sequence to prepare bright, traceable and targeted SERS tags of A549 human lung cancer cells. Furthermore, thiolated-PAA (PAA-SH) was synthesized and utilized for the first time to modify the SERS tags with a layer of negative charges for efficient pH-dependent loading and release of the anticancer drug doxorubicin. Based on the A549 human lung cancer cell model, the availability of the proposed AuNF-nanocarriers for efficient intracellular SERS imaging-guided chemo-phototherapy was studied and the results indicate that the AuNF-based drug delivery system exhibited attractive characteristics such as good stability, efficiency and pH-controlled drug loading and release, traceable and targeted delivery, as well as SERS imaging and chemo-phototherapy functions, and shows great potential for powerful SERS-imaging and as a theranostic candidate for precision nanomedicine that could achieve sensitive and accurate tumor detection and therapy.