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In situ and real-time monitoring of responsive drug release is critical for the assessment of pharmacodynamics in chemotherapy. In this study, a novel pH-responsive nanosystem is proposed for real-time monitoring of drug release and chemo-phototherapy by surface-enhanced Raman spectroscopy (SERS). The Fe3O4@Au@Ag nanoparticles (NPs) deposited graphene oxide (GO) nanocomposites with a high SERS activity and stability are synthesized and labeled with a Raman reporter 4-mercaptophenylboronic acid (4-MPBA) to form SERS probes (GO-Fe3O4@Au@Ag-MPBA). Furthermore, doxorubicin (DOX) is attached to SERS probes through a pH-responsive linker boronic ester (GO-Fe3O4@Au@Ag-MPBA-DOX), accompanying the 4-MPBA signal change in SERS. After the entry into tumor, the breakage of boronic ester in the acidic environment gives rise to the release of DOX and the recovery of 4-MPBA SERS signal. Thus, the DOX dynamic release can be monitored by the real-time changes of 4-MPBA SERS spectra. Additionally, the strong T2 magnetic resonance (MR) signal and NIR photothermal transduction efficiency of the nanocomposites make it available for MR imaging and photothermal therapy (PTT). Altogether, this GO-Fe3O4@Au@Ag-MPBA-DOX can simultaneously fulfill the synergistic combination of cancer cell targeting, pH-sensitive drug release, SERS-traceable detection and MR imaging, endowing it great potential for SERS/MR imaging-guided efficient chemo-phototherapy on cancer treatment.
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As an increasingly mature analytical technique, surface-enhanced Raman spectroscopy has the ability to identify, detect, and even quantitatively measure many single substances in nature. However, in the actual sample analysis, the tested samples were often a mixed system of various substances, and it was impossible to accurately characterize the components of the mixed system only by relying on SERS technology. Therefore, SERS combined with other techniques to accurately determine the measured substances has become an inevitable trend. Through the combination, the deficiency of SERS in detection and characterization was improved, and the purpose of efficient, sensitive and accurate determination of substances to be measured was achieved.
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Objective To distinguish the structural analogues xanthine, theophylline and theobromine by surface-enhanced Raman spectroscopy. Methods Concentrated silver colloid enhancement reagent was prepared as the Raman substrate to increase the number of "hot spots" per unit area, improve the sensitivity of surface-enhanced Raman spectroscopy, enhance the signal strength of the samples and achieve the effective discrimination of structural analogues. Meanwhile, the feasibility of surface-enhanced Raman spectroscopy in practical application was verified by determining serum samples of three mixtures. Results The concentrated silver colloid greatly increased the Raman intensity of the three structural analogues. The spectra of each individual compound and the mixture in the serum system was obtained. The detection limit of the three substances in aqueous solution were 0.005, 0.01 and 0.005 μmol/L respectively. Conclusion Surface-enhanced Raman spectroscopy is a potent technique for distinguishing structural analogues. It is rapid, sensitive and nondestructive to samples. Hence, it can be widely used in the fields of detection, analysis, clinical treatment and diagnosis.
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Objective: To explore the surface-enhanced Raman spectroscopy (SERS) difference of key female fertility indicators, estradiol (E2), anti-Müllerian hormone (AMH) and antral follicle count (AFC) in serum samples of healthy and infertile women, and the possibility of their application in preliminary screening of clinical female fertility. Methods: A total of 236 serum samples of healthy and infertile women of childbearing age were collected from Reproductive Medical Center of the First Affliated Hospital with Nanjing Medical University. The ages of all subjects ranged from 22 to 49 years old, with an average age of (30.8 ± 5.1) years old. The samples were divided into high E2 value group (>5 000 pmol/L, 78 cases) and low E2 value group ( 14, 68 cases) and low AFC value group (<7, 34 cases). Serum SERS analysis was established and Raman spectra of each group were detected. Orthogonal partial least squares discriminant analysis (OPLS-DA), receiver operating characteristic (ROC) curve and permutation test were used to analyze the signals. Results: The Raman spectrum morphology of serum samples was similar between high and low E2 value groups, high and low AMH value groups, and high and low AFC value groups, but the spectral peak intensity of the three indicators was different between the high and low value groups. In the OPLS-DA model, there was an obvious clustering trend in E2, AMH and AFC between the high and low value groups, and the areas under ROC curve were 0.996 and 0.996, 0.995 and 0.995, and 1 and 1 in high and low E2 value groups, high and low AMH value groups, and high and low AFC value groups, respectively. Conclusion: SERS has a potential to be used in the primary screening of female fertility. Serum SERS profle as an auxiliary method for early diagnosis of infertility is worthy of further study.
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Objective A new method for serum detection based on surface-enhanced Raman spectroscopy was explored by comparing the Raman spectra between normal mice and influenza virus-infected mice. Methods The nano-silver sol was used as the active substrate.The Raman spectra of the normal group,the model group and the Tamiflu control group were detected by portable Raman spectroscopy,and the partial least squares discrimina-tion analysis(OPLS-DA)was performed by the orthogonal correction. The number of RNA replicas of influenza virus in lung tissue was measured by RT-PCR as a control method. Results At the 3rd or 5th days,the serum of the normal group,the model group and the Tamiflu control group showed a significant trend. By the ROC curve evaluation,the predictive ability of 3 groups of serum SERS models established by OPLS-DA was high,which could distinguish and differentiate 3 groups of serum. Conclusions The results of SERS and RT-PCR detections were consistent.The preliminary results show that SERS pattern can help to identify and diagnose whether the body is infected with influenza virus.
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The binding mechanism between pterostilbene ( PTE) and human serum albumin ( HSA) was investigated by fluorescence spectrometry and surface enhanced Raman spectroscopy (SERS) under simulated physiological conditions. The experiment result showed that the effect between PTE and HSA was a static fluorescence quenching with F?rsterˊ s non-radioactive energy transformation, and PTE could bind HSA strongly with a 1: 1 molar ratio. The binding distances between PTE and HSA was 1. 495 nm, and the binding constants (KA) between PTE and HSA were 1. 12 × 104 (298 K), 4. 07 × 104 (304 K) and 2. 45 × 105 L/ mol (310 K). SERS revealed that PTE combined with HAS by methoxy group. Thermodynamic data indicated that the interaction between PTE and HSA was mainly hydrophobic interaction. Marker competition experiments pointed out that the primary binding site for PTE was located at site Ⅲ in HSA. Three-dimensional, synchronous fluorescence spectrum and SERS showed that the conformation of HSA changed apparently with the addition of PTE, resulting in the tryptophan residue of HSA exposing to a less hydrophobic micro-environment. However, the conformation of PTE did not change apparently with the addition of HSA.
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A rapid and simple method for the determination of cyanide in blood was developed based on pinhole shell-isolated nanoparticles (pinSHINs)-enhanced Raman spectroscopy and an online lysis-purging and trapping approach.In the online lysis-purging and trapping device, the bound cyanide in blood can be cleaved through sulfuric acid acidification, and transferred into HCN volatile gas, then purged into alkaline solution to form NaCN solution, thus high-efficient liberation and entrapment of cyanide from the methemoglobin-bound form can be achieved.The pinSHINs substrate is quite stable to weaken the gold-dissolution effect caused by cyanide under strong alkaline condition, and therefore the detection window can be prolonged to 1 h comparing with 5 min of AuNPs.A limit of detection down to 10 μg/L and a linear range from 100-2000 μg/L in blood were achieved in this method.This method was further applied to rapid measurement of blood samples of cyanide exposed rats and clinic poisoned patients, which provided a sensitive, selective and reliable way for rapid detection of cyanide poisoning.
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Objective To develop a rapid method for the identification of inactivated C.albicans by surface-enhanced Raman spectroscopy (SERS).Methods Live C.albicans cultures were exposed to heating, formaldehyde and fungicidal drug (amphotericin B).The corresponding SERS spectra were acquired for the investigation and comparison.Results The spectra acquired with three different inactivation methods exhibited similar features of dead C.albicans, which showed significant difference from the spectra of the live culture.Conclusion This SERS method can identify the inactivated C.albicans rapidly.Hopefully it will provide a convenient tool for quick identification of other inactivated pathogenic microorganisms.
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Objective:To establish a surface enhanced Raman spectroscopy ( SERS) technique for the determination of atropine sulfate. Methods:The Raman peaks of atropine sulfate molecules were classified by theoretical calculations and experimental tests, and the 1002 cm-1 Raman peaks were selected as the characteristic peaks for the quantitative analysis. Results:The detection limit of atropine sulfate in aqueous solution was below 0. 5 μg·ml-1 . The relationship between the intensity of characteristic peaks at 1002 cm-1 and the concentration of aqueous solution was linear within the range of 1-8 μg ml-1 with the linear correlation coefficient r of 0. 9839. The recovery rates of 2, 5 and 7μg ml-1 were measured, which were 97. 1%-109. 8%. The average recovery was 103. 3%, and the RSD was 4. 5% (n=9). At the same time, the stability of the method among the batches was tested, and the relative standard deviation was 5. 7 %. In addition, the atractylodes rhizome samples containing atropine sulfate were detected,and the characteristic peaks still could be detected at 1002 cm-1 . Conclusion:The method is rapid, accurate and nondestructive with easy operation, which can be used for the detection of atropine sulfate.
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The core-shell nanopaticles of Au@polyvinyl-pyrrolidone ( PVP) with uniform size and controllabe shell-thickness were prepared by hydrothermal method. The core-shell nanoparticles could be assembled to be the monolayer array on Si substrate relying on the dispersion of core-shell nanoparticles arising from PVP shell. The malachite green ( MG ) absorbed by H-bond could be detected on the array under the electromagnetic enhancement of inner-core Au nanoparticles. Under the conditions of the optimum shell-thickness of Au@PVP and the appropriate absorbed time of MG, the detection of MG could be realized in the linear range from 1 × 10-10 mol/L to 1 × 10-5 mol/L with the correlation coefficient ( R2 ) of 0. 98. The detection limit was 10-12 mol/L. This method was applied to the determination of MG in tilapia fish fillets of Xiagang market. No MG was found in this real sample. The spiked recoveries of the sample ranged from 70. 8% to 126. 0%. This method is simple and accurate, and can be used for detection of MG in the fish.
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Due to its exquisite sensitivity, excellent molecular specificity and reduced photobleaching, surface-enhanced Raman spectroscopy has wide potential applications in the fields of food and drug analysis, environmental monitoring and biological detection. However, SERS is only a qualitative or semi-quantitative detection technique at the present stage, and has not yet been widely recognized as a routine quantitative technique. This review discusses the pros and cons of the quantitative surface-enhanced Raman spectroscopic techniques developed so far in the literature, and looks forward to the future trend in this field.
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A novel method based on the separation and enrichment effect of magnetic beads and the fully complementary hybridization of two DNA strands was developed for highly sensitive detection of bacterial DNA using a surface-enhanced Raman spectroscopy (SERS) with 5,5’-dithio-bis(2-nitrobenzoic acid) (DTNB)-modified gold nanoparticles as reporter probes. Capture probe was immobilized onto the surface of streptavidin-enwrapped magnetic beads ( SA-MB ) through high affinity between biotin and avidin, by which the target bacterial DNA sequences that connected with the reported probe decorated AuNPs with DTNB and SH-DNA ( AuNPs@DTNB@DNA) were captured and loaded onto the magnetic beads by the hybridization reaction with the capture probe. Compared with previous methods, this design shortened the distance between particles by the ways that the magnetic beads tempted to nanoparticles aggregation, and produced the plasma resonance coupling effect, which increased the SERS signal significantly. The results showed that, under the optimized conditions and in the concentration range from 5 pmol/L to 5 nmol/L, the method performed a good linear relationship between Raman intensity and DNA concentration. The limit of detection ( LOD) of bacterial DNA was estimated to be 5 pmol/L. The method is simple and low cost, and can be used in the sensitive and selective detection of bacterial DNA.
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Objective To prepare hybrid substrate and apply it to detect thiram with surface-enhanced Raman spectros-copy( SERS) which provides unique molecular vibration information .Methods The Au substrate was prepared by deposi-tion of gold film on the silver substrate that had a rough surface .The Au substrate was treated with amination as a linker with the silver sol before the hybrid substrate was formed .With PATP as a probe molecule ,the Raman intensity of PATP on the Au substrate and the hybrid substrate was compared ,respectively .Results and Conclusion PATP had stronger Raman intensity on hybrid substrate than on the Au , and the detection limit was 10 -9 mol/L.This method can be used for quanti-tative detection on the hybrid substrate by SERS .
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Objective To develop a rapid SERS detection method based on monolithic column for detection of dye adul-terated natural indigo .Methods The dyes in natural indigo were extracted and mixed with silver colloid .The spectra were re-corded after applying the mixture solution to the monolithic column since the intertwined pores in monolithic column could con-tribute for the distribution of silver nanoparticles .Results SERS signals of malachite green dyed natural indigo at quantity as low as 500 μg/kg could be obtained .Conclusion This simple ,fast and specific SERS detection method based on monolithic col-umn could be used for rapid detection of stained natural indigo .
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Objective:To study the surface enhanced Raman scattering ( SERS) of safflower and identify safflower injections by SERS quickly and effectively. Methods:Through comparative analysis of the Raman spectroscopy of safflower injections and the corre-sponding control herbs, the rapid identification of safflower injections was realized. Results:The results showed that several character-istic peaks of safflower were enhanced obviously in SERS, which could be used to identify safflower injections. Conclusion:The meth-od is reliable, rapid, accurate and specific, which can be applied as a method to identify safflower and its injections.
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<p><b>OBJECTIVE</b>To establish Surface-enhanced Raman Spectroscopy (SERS) can be used as a rapid and reliable method to distinguish virulent strain and mild strain of L. pneumophila.</p><p><b>METHODS</b>Mortality data were collected from company departments through administrative documents, death certificates, etc. Trend analyses of cancer mortality were performed on the basis of 925 cancer deaths between 2001 and 2010.</p><p><b>RESULTS</b>Our results indicated that the peaks of high virulence strains reached ⋝4000. This criterion was verified by subsequent cell experiments. In addition, we also conducted SERS rapid identification on the virulence of several collected clinical strains and obtained accurate results.</p><p><b>CONCLUSION</b>The present study indicates that the established SERS protocol can be used as a rapid and reliable method to distinguish virulent and mildly virulent strains of L. pneumophila, which can be further used in clinical samples.</p>
Subject(s)
Humans , Cell Line , Citric Acid , Chemistry , Gold , Chemistry , Legionella , Virulence , Nanoparticles , Chemistry , Spectrum Analysis, Raman , Methods , Time Factors , Tiopronin , Chemistry , VirulenceABSTRACT
Objective To establish detection method of glinides adulterated illegally in hypoglycemic traditional Chinese medi -cine (TCM) by surface enhanced Raman spectroscopy (SERS).Methods Adulterated chemicals and TCM matrixes were separated by TLC first.Then trace substances in TLC plate was tested by SERS method .By investigating SERS detection conditions of glinides chemi-cals in simulated positive samples , a detection method was established to detect illegal adulterant in hypoglycemic TCM .Results Better SERS spectra of glinides could be obtained by silver sol prepared with organic solvent DMF .Conclusion The detection method coupled with TLC and SERS in this paper was simple , fast and economical which could be used to detect glinides adulterated illegally in hypogly -cemic Chinese patent medicine quickly .
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Objective To identify the normal breast tissue and breast fibroadenoma tissue by shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS),and to explore the biological characteristics of FD and the identification method by discussing its spectroscope characteristics.Methods The frozen section of 26 patients (all female,aged 19-59 years)were obtained by routine surgical resection.9 cases of normal tissue and 17 cases of breast fibroadenoma tissue were detected by Raman spectroscopy and then SHINERS technique was utilized.A total of 243 Raman and 273 SHINERS spectra were obtained.All the spectra were dealt with baseline corrected by fitting and subtracting a third-order polynomial and then smoothed with a 15-point Adjacent-Averaging.Results The characteristic peaks of normal breast tissue appeared in 1 090,1 157,1 262,1 300,1 442,1 658,1 745,and 1 874 cm-1 .After adding SHINs, some peaks shifted in 2 - 3 cm-1 , the relative strengths of 1 090 and 1 157 cm-1 were significantly increased,and the 1 496 cm-1 characteristic peak appeared.The main characteristic peaks of breast fibroadenoma appeared in 751,880,930,880,1 262,1 442,1 579,1 658,and 1 745 cm-1;one of the dominant characteristic peak should belong to lipids,but it can be seen that amideⅠ characteristic peak of protein became more significant.Conclusion Raman spectra can discover the differences of the characteristic peaks of amide Ⅰ between breast fibroadenoma and normal breast tissues. By virtue of different enhancement effects of SHINs to Raman specific peaks of the various tissues, breast fibroadenoma can be distinguished from normal tissue successfully.