Surface-enhanced Raman scattering reveals adsorption of mitoxantrone on plasma membrane of living cells

Application of green-synthesized carbon dots for imaging of cancerous cell lines and detection of anthraquinone drugs using silica-coated CdTe quantum dots-based ratiometric fluorescence sensor

Chemotherapy drugs of daunorubicin and doxorubicin treat cancers with many side effects. So, detection of them in the biological system for regulation and controlling of usage is essential. In this study, a ratiometric fluorescent method was introduced for detection of daunorubicin and doxorubicin using bell pepper-based carbon dots, as the variable signal, and silica-coated CdTe quantum dots, as the constant signal. The detection was done based on variations of carbon dots intensity in the presence of drugs in comparison with the constant intensity of silica-coated CdTe quantum dots. The proposed ratiometric fluorescent method was successfully used for detection of daunorubicin and doxorubicin range of 54.37-13594.34 nmolL^-1 and 86.2-17242 nmolL^-1, with a detection limit of 18.53 nmolL^-1 and 29 nmolL^-1, respectively. Also, this method was used for detection of drugs in serum samples with recovery ranges of 86.14-99.62 (RSD 3-1.47%) and 86.32-97.53 (3.38-1.48%), respectively. Finally, after evaluation of carbon dots toxicity by MTT test, carbon dots was applied for imaging of prostate cancer cell lines (PC-3) and breast cancer cell lines (MCF7). The results demonstrated that despite improvement of the repeatability and interferences reduction by ratiometric method, also carbon dots were successfully applied for imaging of cell lines.

An eco-friendly matrix-augmented fluorescence spectroscopic approach for the analysis of mitoxantrone, an oncogenic therapy; application to the dosage form and biological matrices

Mitoxantrone (MXN) is a synthetic anthracenedione oncogenic therapy. It is often prescribed as an anticancer agent to manage a variety of cancers. A green, fast, and easy fluorimetric technique for the assay of MXN as a topoisomerase type II enzyme suppressor. An investigation of MXN's fluorescence behavior in various media and solvents constituted the basis for this new technique. Methanol was shown to enhance the intrinsic fluorescence considerably. After excitation at 610 nm, the highest fluorescence intensity was found at 675 nm. Various experimental parameters, such as media, solvents, and pH levels, were tested and adjusted. ICH (International Conference on Harmonization) guidelines were followed when validating procedures. It was possible to achieve linearity in the 0.02-1.50 μg ml^-1 with the method. The sensitivity (in terms of limit of detection and limit of quantification) was 0.003 and 0.008 μg ml^-1 , indicating low toxicity. As a result, the current technology has a remarkable recovery for detecting residues in diverse bodily fluids. Also, the quantum yield was estimated for the designed system. Finally, the method was rated by eco-scale scoring.

Surface-enhanced infrared absorption spectroscopy for microorganisms discrimination on silver nanoparticle substrates

Extracting molecular level label-free information from complex biological processes for a range of purposes including disease diagnosis and microbial identification and discrimination is always a challenging task. This is mostly due to lack of a technique providing rich molecular information with a high spatial and temporal resolution properties. Two surface-enhanced vibrational spectroscopic (SEVS) techniques, surface-enhanced Raman scattering (SERS) and surface-enhanced infrared absorption spectroscopy (SEIRAS), are recently attracting considerable attention to study biosystems at an interface since they can satisfy these requirements to a certain level by providing rich intrinsic molecular information from molecules and molecular systems in a close proximity of nanostructured noble metal surfaces. In this study, these two surface-enhanced vibrational spectroscopic techniques are comparatively evaluated for the discrimination and identification of Candida albicans (C. albicans), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by paying attention to the source of the observed spectral pattern. The citrate-reduced colloidal silver nanoparticles (AgNPs) were used as substrates. The results show that the SEIRAS provides very rich molecular information about the biomolecular species adsorbed onto AgNPs similar to the case of SERS. The discrimination power of SEIRAS is much improved compared to FTIR demonstrated by PCA analysis. This study suggests that SEIRAS can be a potential technique for microbial analysis.

A simple single jar “on–off fluorescence” designed system for the determination of mitoxantrone using an eosin Y dye in raw powder, vial, and human biofluids

This work describes a green fluorescence on–off system that relies on establishing a simple ion association complex pairing the mitoxantrone antineoplastic drug with the eosin Y reagent in a slightly acidic solution.

Investigating the interaction of mitoxantrone with anionic surfactants by spectrofluorimetry and its application for the feasible analysis of pharmaceutical preparation and biological fluids

The behaviour of mitoxantrone (MTX), an anthracenedione antineoplastic agent, in different types of organized medium was explored using molecular spectrofluorometry. The original fluorescence and quantum yield of MTX were augmented by about five-fold in the aqueous buffered solution (Britton-Robinson, pH 3.0) by the addition of sodium dodecyl sulfate. Enhancement in the fluorescence intensity did not come from the boost in the ultraviolet (UV) light absorbance of the drug in the presence of micelles but due to shielding of the lowest excited singlet state of the drug from a radiationless process inside the cavity of the micelle. Accordingly, a versatile, sensitive, and feasible spectrofluorimetric method was constructed and evaluated for MTX determination. Fluorescence measurements were performed at 675 nm (λ_ex 610 nm). A linear relationship was shown between fluorescence intensity and drug concentration within the range 0.01-2.0 μg ml^-1 of MTX with a correlation coefficient of 0.9999 and a detection limit of 2 ng ml^-1 . The developed method was effectively used for analysis of MTX in biological samples and dosage forms. In addition, the method was expanded to study the stability of MTX exposed to different drastic degradations and the kinetic parameters of the degradation were calculated.

Nuclear cytometry and chromatin organization

The nuclear-targeting chemical probe, for the detection and quantification of DNA within cells, has been a mainstay of cytometry-from the colorimetric Feulgen stain to smart fluorescent agents with tuned functionality. The level of nuclear structure and function at which the probe aims to readout, or indeed at which a DNA-targeted drug acts, is shadowed by a wide range of detection modalities and analytical methods. These methods are invariably limited in terms of the resolution attainable versus the volume occupied by targeted chromatin structures. The scalar challenge arises from the need to understand the extent and different levels of compaction of genomic DNA and how such structures can be re-modeled, reported, or even perturbed by both probes and drugs. Nuclear cytometry can report on the complex levels of chromatin order, disorder, disassembly, and even active disruption by probes and drugs. Nuclear probes can report defining features of clinical and therapeutic interest as in NETosis and other cell death processes. New cytometric approaches continue to bridge the scalar challenges of analyzing chromatin organization. Advances in super-resolution microscopy address the resolution and depth of analysis issues in cellular systems. Typical of recent insights into chromatin organization enabled by exploiting a DNA interacting probe is ChromEM tomography (ChromEMT). ChromEMT uses the unique properties of the anthraquinone-based cytometric dye DRAQ5™ to reveal that local and global 3D chromatin structures effect differences in compaction. The focus of this review is nuclear and chromatin cytometry, with linked reference to DNA targeting probes and drugs as exemplified by the anthracenediones.

State of diagnosing infectious pathogens using colloidal nanomaterials

Infectious diseases are a major global threat that accounts for one of the leading causes of global mortality and morbidity. Prompt diagnosis is a crucial first step in the management of infectious threats, which aims to quarantine infected patients to avoid contacts with healthy individuals and deliver effective treatments prior to further spread of diseases. This review article discusses current advances of diagnostic systems using colloidal nanomaterials (e.g., gold nanoparticles, quantum dots, magnetic nanoparticles) for identifying and differentiating infectious pathogens. The challenges involved in the clinical translation of these emerging nanotechnology based diagnostic devices will also be discussed.

Optical nano antennas: state of the art, scope and challenges as a biosensor along with human exposure to nano-toxicology

The concept of optical antennas in physical optics is still evolving. Like the antennas used in the radio frequency (RF) regime, the aspiration of optical antennas is to localize the free propagating radiation energy, and vice versa. For this purpose, optical antennas utilize the distinctive properties of metal nanostructures, which are strong plasmonic coupling elements at the optical regime. The concept of optical antennas is being advanced technologically and they are projected to be substitute devices for detection in the millimeter, infrared, and visible regimes. At present, their potential benefits in light detection, which include polarization dependency, tunability, and quick response times have been successfully demonstrated. Optical antennas also can be seen as directionally responsive elements for point detectors. This review provides an overview of the historical background of the topic, along with the basic concepts and parameters of optical antennas. One of the major parts of this review covers the use of optical antennas in biosensing, presenting biosensing applications with a broad description using different types of data. We have also mentioned the basic challenges in the path of the universal use of optical biosensors, where we have also discussed some legal matters.

Surface-enhanced Raman scattering-based detection of cancerous renal cells

Surface-enhanced Raman scattering (SERS) is used for the differentiation of human kidney adenocarcinoma, human kidney carcinoma, and non-cancerous human kidney embryonic cells. Silver nanoparticles (AgNPs) are used as substrate in the experiments. A volume of colloidal suspension containing AgNPs is added onto the cultured cells on a CaF(2) slide, and the slide is dried at the overturned position. A number of SERS spectra acquired from the three different cell lines are statistically analyzed to differentiate the cells. Principal component analysis (PCA) combined with linear discriminate analysis (LDA) was performed to differentiate the three kidney cell types. The LDA, based on PCA, provided for classification among the three cell lines with 88% sensitivity and 84% specificity. This study demonstrates that SERS can be used to identify renal cancers by combining this new sampling method and LDA algorithms.

Surface-Enhanced Raman Scattering: A Technique of Choice for Molecular Detection

Although surface-enhanced Raman scattering (SERS) has crossed its infancy long ago, it is yet to persuade different challenges to make it available in day-to-day applications. SERS is being criticized mainly due to the quality of the SERS analyses that uses substrates to get the giant enhancement for respective Raman signal of the target molecule. Hence, understanding the phenomena behind substrates, cost-effective development and optimization of such substrates for routine analytical purposes and utilization of modern modalities to get the insights out has become a very wide-spreading and interesting area of research. In this piece of work, several key terminologies related to SERS have been presented in brief. Since SERS is a localized surface plasmon resonance (LSPR) mediated signal-enhancing phenomena, it is indispensable to understand the correlation between LSPR excitations originated from substrate and SERS signal originated from molecules. A wide range of SERS-active substrates including scattered nanoaggregates, anisotropic assembly, two-dimensional nanostructure, multi-layered nanostructure of gold nanoparticles and colloidal approach have been used to interpret such correlation between LSPR excitations and SERS characteristics. Few exemplary applications of SERS have been also mentioned followed by typical simulative work how nanoobject behaves at different excitations and polarizations.

Localized surface plasmon resonance: nanostructures, bioassays and biosensing--a review

Localized surface plasmon resonance (LSPR) is an optical phenomena generated by light when it interacts with conductive nanoparticles (NPs) that are smaller than the incident wavelength. As in surface plasmon resonance, the electric field of incident light can be deposited to collectively excite electrons of a conduction band, with the result being coherent localized plasmon oscillations with a resonant frequency that strongly depends on the composition, size, geometry, dielectric environment and separation distance of NPs. This review serves to describe the physical theory of LSPR formation at the surface of nanostructures, and the potential for this optical technology to serve as a basis for the development bioassays and biosensing of high sensitivity. The benefits and challenges associated with various experimental designs of nanoparticles and detection systems, as well as creative approaches that have been developed to improve sensitivity and limits of detection are highlighted using examples from the literature.

Mitoxantrone changes spectrin-aminophospholipid interactions

Understanding drug-membrane and drug-membrane protein interactions would be a crucial step towards understanding the action and biological properties of anthracyclines, as the cell membrane with its integral and peripheral proteins is the first barrier encountered by these drugs. In this paper, we briefly describe mitoxantrone-monolayer and mitoxantrone-bilayer interactions, focusing on the effect of mitoxantrone on the interactions between erythroid or nonerythroid spectrin with phosphatidylethanolamine-enriched mono- and bilayers. We found that mitoxantrone markedly modifies the interaction of erythroid and nonerythroid spectrins with phosphatidylethanolamine/phosphatidylcholine (PE/PC) monolayers. The change in delta pi induced by spectrins is several-fold larger in the presence of 72 nM mitoxantrone than in its absence: spectrin/mitoxantrone complexes induced a strong compression of the monolayer. Spin-labelling experiments showed that spectrin/mitoxantrone complexes caused significant changes in the order parameter measured using a 5'-doxyl stearate probe in the bilayer, but they practically did not affect the mobility of 16'-doxyl stearate. These results indicate close-to-surface interactions/penetrations without significant effect on the mid-region of the hydrophobic core of the bilayer. The obtained apparent equilibrium dissociation constants indicated relatively similar mitoxantrone-phospholipid and mitoxantrone-spectrin (erythroid and nonerythroid) binding affinities. These results might in part, explain the effect of mitoxantrone on spectrin distribution in the living cells.

Formation of colloidal silver nanoparticles stabilized by Na+–poly(γ-glutamic acid)–silver nitrate complex via chemical reduction process

Macromolecular and polyanionic Na(+)-poly(gamma-glutamic acid) (PGA) silver nitrate complex acted as both a metal ion provider and a particle protector to fabricate nanosized silver colloids under chemical reduction by dextrose. The formation and size of particles have been characterized from transmission electron microscopy (TEM), dynamic light scattering analysis and UV-vis spectrophotometer. The results showed that the average particle size was 17.2+/-3.4 to 37.3+/-5.5 nm, apparently depending on the complex concentration. It was found that the rate constant and conversion of silver nanoparticles were proportional to the concentration of PGA. The growth mechanism of nanosized silver colloid was fully discussed. In addition, the in vitro cytotoxicity evaluated by L929 fibroblasts proliferation and antibacterial activity against Gram-positive strain (methicillin-resistant S. aureus (MRSA)) and Gram-negative strain (P. aeruginosa) bacteria have been assessed.

Resonance Rayleigh scattering spectra for studying the interaction of anthracycline antineoplastic antibiotics with some anionic surfactants and their analytical applications

In pH 5.8 acidic medium, the anionic surfactants such as sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) or sodium dodecyl sulfonate (SLS) can react with anthracycline antibiotics such as epirubicin (EPI), daunorubicin (DNR) or mitoxantrone (MXT) to form ion-association complexes, which lead to a great enhancement of resonance Rayleigh scattering (RRS) intensity and appearances of new RRS spectra. The maximum RRS peaks are situated at 313 nm for SDS-DNR and SDS-EPI system, 296 nm for SDS-MXT system. The linear ranges and detection limits for EPI, DNR and MXT are 0.26-20.0, 0.25-20.0, 0.14-10.0 and 0.074, 0.078, 0.042 microgmL(-1), respectively. In this paper, the characteristics of the absorption, fluorescence and RRS spectra of the reaction products are studied as well as the optimum reaction conditions and analytical chemistry properties. A sensitive, simple and rapid RRS method for the determination of anthracycline anticancer antibiotics has been developed.

Energy transfer to analyse membrane-integrated mitoxantrone in BCRP-overexpressed cells

The binding and the diffusion of mitoxantrone (MTX) through the plasma membrane was performed by Förster resonance energy transfer (FRET) from the membrane fluorescent donor (4Di-10ASP) to the co-localized acceptor MTX. The MTX addition to living 4Di-10ASP-tagged cells resulted in the rapid quenching of the probe emission (1s), revealing the MTX binding to the outer leaflet. Then, a slower quenching (about 90s) occurred which corresponded to the MTX flip-flop into the inner leaflet. Changes of MTX integration into the plasma membrane were described in BCRP-overexpressed cells (HCT-116R) treated with (i) the BCRP inhibitor fumitremorgin C (FTC), (ii) cyclosporin A (CSA) and (iii) benzyl alcohol (BA). Treatments with FTC or CSA showed 80% and 40% higher flip-flop of MTX from the outer to the inner leaflet of HCT-116R cells. The addition of BA clearly increased the MTX integration into both outer and inner leaflets. Confocal fluorescence microscopy displayed that FTC, CSA and BA enhanced MTX accumulation in HCT-116R. In conclusion, Fumitremorgin C and agents modulating MTX accumulation resulted in higher MTX integration in the resistant cell membrane and could disrupt the membrane cohesion. This energy transfer method appears well-adapted to describe the drug diffusion through the plasma membrane of living cells.

Role of ABCG2/BCRP in biology and medicine

The protein variously named ABCG2/BCRP/MXR/ABCP is a recently described ATP-binding cassette (ABC) transporter originally identified by its ability to confer drug resistance that is independent of Mrp1 (multidrug-resistance protein 1) and Pgp (P-glycoprotein). Unlike Mrp1 and Pgp, ABCG2 is a half-transporter that must homodimerize to acquire transport activity. ABCG2 is found in a variety of stem cells and may protect them from exogenous and endogenous toxins. ABCG2 expression is upregulated under low-oxygen conditions, consistent with its high expression in tissues exposed to low-oxygen environments. ABCG2 interacts with heme and other porphyrins and protects cells and/or tissues from protoporphyrin accumulation under hypoxic conditions. Individuals who carry ABCG2 alleles that have impaired function may be more susceptible to porphyrin-induced toxicity. Abcg2 knock-out models have allowed in vivo studies of Abcg2 function in host and cellular defense. In combination with immunohistochemical analyses, these studies have revealed how ABCG2 influences the absorption, distribution, and excretion of drugs and cytotoxins.

Microspectroscopies fonctionnelles du vivant. Approches cellulaires et tissulaires

The interaction between living matter and optical spectra (Raman, infrared, fluorescence spectroscopy) can be used to characterize simple or complex biomolecular systems. At the cell and tissue level, these microspectroscopic techniques can be used to construct descriptors of molecular or supramolecular (nucleic acids, proteins, lipids, etc.) function in a given biological situation (healthy or pathological tissue, normal or pathological cell, induction of cytotoxicity, apoptosis or differentiation, presence or not of a resistance phenotype, etc.) At the present time vibrational spectroscopy appears to be a particularly powerful technique for characterization of the early phases of pathological processes occurring within given cells or tissues. It could be used to develop tools for early diagnosis and prediction of therapeutic response.

Surface enhanced Raman scattering for narcotic detection and applications to chemical biology

Raman spectroscopy is rapidly finding favour for applications in the life science because of the ease with which it can be used to extract significant data from tissue and cells. However, the Raman effect is an inherently weak effect, which hinders the analysis of low concentration analytes. Raman sensitivity can be improved via the surface enhanced Raman scattering (SERS) effect. In SERS, Raman spectra are dramatically amplified when a molecule is adsorbed onto nano-roughened noble metal surfaces such as silver and gold. The degree of enhancement enables single-molecule detection, which offers the potential for the unambiguous identification of analytes at concentrations that are useful in both a forensic and a chemical biology context. Here we discuss some of the practical applications of SERS to both low-level narcotic detection, and how this can be applied to chemical biology.

Resonance contributions to anti-Stokes/Stokes ratios under surface enhanced Raman scattering conditions

Anti-Stokes/Stokes asymmetries under surface enhanced Raman scattering (SERS) conditions are studied for a wide variety of SERS-active media and different analytes. Evidence is provided for the existence of underlying resonances that create these asymmetries. We show here that these resonances are associated with the electromagnetic coupling between the analyte (probe) and the metal. The work demonstrates the use of the anti-Stokes/Stokes ratio as a tool to understand the hierarchy of resonances in the SERS problem, which is essential for quantification purposes.

Changes in adsorption and permeability of mitoxantrone on plasma membrane of BCRP/MXR resistant cells

A selective analysis of adsorbed mitoxantrone (MTX) was performed by surface-enhanced Raman scattering (SERS) at the range of cellular membrane. Disruption of the membrane fluidity was carried out to appraise changes in membrane adsorption of MTX and drug uptake in sensitive (HCT-116 S) and resistant BCRP/MXR (HCT-116 R) cells. Based on spectral MTX modifications, micro-SERS spectroscopy discriminated clearly drug adsorption phenomena on plasma membrane from drug in solution. A 3-fold higher SERS intensity of MTX for HCT-116 R was observed concluding to a higher drug adsorption on resistant membrane. The increase of membrane fluidity with benzyl alcohol (BA) or chloroform (CF) resulted in a 3-fold decrease of MTX adsorption on HCT-116 R, exclusively. BA and CF improved intracellular accumulation of MTX (e.g., 823 and 191 pmol MTX/10(6) HCT-116 R incubated with or without BA). At 4 degrees C, drug accumulation measurements showed a decrease of MTX permeability in resistant membrane (42 pmol MTX/10(6) cells), restored with fluidizers (e.g., 342 pmol MTX/10(6) cells with BA). Fluorescence confocal microscopy involved an exclusive MTX emission around the plasma membrane of resistant cells whereas fluidizers increased the intracellular uptake of MTX in both cell lines at the same time with less drug emission around the plasma membrane. Changes of the membrane structure of resistant cells should modify both drug adsorption and membrane permeation.