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Vibrational spectroscopy, encompassing Raman and Infrared (IR) spectroscopy, is a powerful technique that probes the intrinsic vibrations of a molecule, thus providing a unique chemical signature for that molecule. This information is beneficial to differentiate between two similarly structured molecules since their vibrational fingerprint will be different. In an effort to introduce an automated spectroscopic data analysis tool, we explore different Machine Learning (ML) algorithms to identify the chemical structure from the simulated Raman and IR spectra of 22 similar molecules belonging to the class of cannabinoids. In this study, we investigate the best ML approach by using representative synthetic IR/Raman data obtained from quantum chemical calculations of the selected molecular structures. We account for the experimental variability of the spectra by adding different kinds of noise and backgrounds to the simulated spectra such that they mimic experimental conditions such as fluorescence background as well as Gaussian noise. This methodology is used to setup the database to train the ML algorithms. We report the accuracy of the different ML algorithms and the time taken to process the algorithms in differentiating the cannabinoid varieties.

Colorimetric assays typically offer a rapid and convenient method to assess analytes that span healthcare monitoring to water quality testing. However, such tests can only provide qualitative results when employed in resource-limited settings or require bulky and expensive equipment such as lab spectrophotometers to allow quantitative measurements. In this paper, we report on the use of a handheld colorimeter to quantitatively determine the concentration of analytes in a manner that is independent of ambient lighting or initial sample color. The method combines the response of the sensor with first-principles modeling that better describes the nature of the assay compared to linear-in-parameters regression modeling that is typically performed in other studies. This method was successfully demonstrated using a number of colorimetric assays: (1) determination of solution pH using a universal indicator, (2) quantification of the DNase presence using a DNA-gold nanoparticle assay, and (3) quantification of the concentration of the antibiotic tetracycline using a cell-based assay.

The development of analytical techniques that decode chemical information in complex biochemical samples to discriminate different structural components may open the way for several new findings. In this study, principal component analysis (PCA) is carried out using an ad hoc Matlab coding that provides a transparent access to multivariate analysis of Raman mapping datasets. Here, we illustrated the efficacy of this method to extract meaningful results from Raman images of Cannabis sativa trichomes. A large dataset of Cannabis trichome comprising of 441 Raman spectra was examined for the first time using our OpenPCA. By mapping the chemical distribution in the trichome, we could locate the secretary vesicles in the PC score maps generated from the mapped Raman spectra. Black-box PCA solutions available in commercial software can be limited by rigid input interfaces which may prevent obtaining information by tuning the PCA analysis on selected wavenumber ranges. Hence, the OpenPCA scripts facilitate the task of obtaining key information from widely distributed range of wavenumbers that are characteristic to a specific cannabinoid, namely Δ9-THC and CBD. Overall, the PCA-coding algorithm shows advantages in decoding Raman spectra that could be extended to handle all kinds of datasets with simultaneous spatial and chemical details.

The development of analytical techniques that decode chemical information in complex biochemical samples to discriminate different structural components may open the way for several new findings. In this study, principal component analysis (PCA) is carried out using a novel coding approach through a Matlab interface that provides a transparent access to multivariate analysis of Raman mapping datasets. Here, we illustrated the efficacy of this method to extract meaningful results from Raman images of Cannabis sativa trichomes. A large dataset of Cannabis trichome comprising of 441 Raman spectra was examined for the first time using our OpenPCA. By mapping the chemical distribution in the trichome, we could locate the secretary vesicles in the generated PC score curves from the Raman spectrum. Black-box PCA solutions available in commercial software can be limited by rigid input interfaces which may prevent obtaining information by tuning the PCA analysis on selected wavenumber ranges. The OpenPCA scripts facilitate the task of obtaining key information from widely distributed range of wavenumbers that are characteristic to a specific cannabinoid, namely Δ9-THC and CBD. Overall, the PCA-coding algorithm shows advantages in decoding Raman spectrum which could be extended to handle all kinds of datasets with simultaneous spatial and chemical details.

The synthesis and property characterization of soft biomaterials has taken precedence in recent years. Although bulk physical-chemical properties are well known for these bio-materials, nanoscale properties still need to be probed and evaluated to fine tune the bio-compatibility (structural as well as functional) with natural tissues for regenerative medicine, prosthetics and other biological applications. In this study, we focus on a popular soft biomaterial, ELastin-like polypeptide (ELP) which has been prepared under different pH conditions. We explore the topographical features of the ELP at the nanoscale using Atomic Force Microscopy (AFM). Additionally, we employ a non linear mode of AFM called Intermodulation-AFM (ImAFM) to correlate the elastic properties (Young's modulus) of ELP probed at the nanoscale with the topographical features which gives us a deep insight into the mechanical properties offered by ELP when the structural features are altered by change in the ELP synthesis conditions. The noteworthy point is that we measure theses properties at a spatial resolution of 0.9 nm. Finally, we explain the change in the structural features of ELP with varying pH through atomistic Molecular Dynamics Simulations. We follow the interaction mechanisms of the amino acid sequences and crosslinkers with proteins as they form the backbone and sidechain of the ELP at different pH.

We propose a two-frequency driving scheme in dynamic atomic force microscopy that maximizes the interaction time between tip and sample. Using a stochastic description of the cantilever dynamics, we predict large classical squeezing and a small amount of skewness of the tip's phase-space probability distribution. Strong position squeezing will require close contact between tip and surface, while momentum squeezing would also be possible in the van der Waals region of the tip-surface force. Employing a generalized Caldeira-Leggett model, we predict that surface-dependent dissipative forces may be the dominant source of quantum effects and propose a procedure to isolate quantum effects from thermal fluctuations., 21 pages, 6 figures

The synthesis and property characterization of soft biomaterials has taken precedence in recent years. Although bulk physical-chemical properties are well known for these bio-materials, nanoscale properties still need to be probed and evaluated to fine tune the bio-compatibility (structural as well as functional) with natural tissues for regenerative medicine, prosthetics and other biological applications. In this study, we focus on a popular soft biomaterial, ELastin-like polypeptide (ELP) which has been prepared under different pH conditions. We explore the topographical features of the ELP at the nanoscale using Atomic Force Microscopy (AFM). Additionally, we employ a non linear mode of AFM called Intermodulation-AFM (ImAFM) to correlate the elastic properties (Young's modulus) of ELP probed at the nanoscale with the topographical features which gives us a deep insight into the mechanical properties offered by ELP when the structural features are altered by change in the ELP synthesis conditions. The noteworthy point is that we measure theses properties at a spatial resolution of 0.9 nm. Finally, we explain the change in the structural features of ELP with varying pH through atomistic Molecular Dynamics Simulations. We follow the interaction mechanisms of the amino acid sequences and crosslinkers with proteins as they form the backbone and sidechain of the ELP at different pH.

Background: Psoriasis is a systemic inflammatory disease characterized by epidermal proliferation in the skin. Altered lipid metabolism is considered to be a central factor in the psoriatic etiopathogenesis. Thus, it is necessary to visualize chemical specificity of the samples for better medical diagnosis and treatment. Here, we investigate its role in the development of psoriatic lesions, before and after ultraviolet phototherapy, in a case study. Methods: The distribution and morphology of different lipids and fibrous proteins in psoriatic (lesional) tissues were visualized by two complementary label-free imaging techniques: 1) non-linear microscopy (NLM), providing images of lipids/proteins throughout the skin layers at submicrometer resolution; and 2) mass spectrometry imaging (MSI), offering high chemical specificity and hence the detection of different lipid species in the epidermal and dermal regions. A conventional method of histological evaluation was performed on the tissues, with no direct comparison with NLM and MSI. Results: Psoriatic tissues had a higher lipid content, mainly in cholesterol, in both the epidermal and dermal regions, compared to healthy tissues. Moreover, the collagen and elastin fibers in the psoriatic tissues had a tendency to assemble as larger bundles, while healthy tissues showed smaller fibers more homogeneously spread. Although phototherapy significantly reduced the cholesterol content, it also increased the amounts of collagen in both lesional and non-lesional tissues. Conclusion: This study introduces NLM and MSI as two complementary techniques which are chemical specific and can be used to assess and visualize the distribution of lipids, collagen, and elastin in a non-invasive and label-free manner.

Gold thin films with remarkable Surface Enhanced Raman scattering activity strongly dependent on their surface nanostructure were grown by nanosecond pulsed laser ablation. By changing the number of the laser pulses, keeping fixed all the other deposition parameters, we deliberately modified the surface nanostructure of the films. These nanostructured films consist of metallic islands separated from each other by inter-island channels. We observed differences in both island sizes and inter-island channel sizes as a function of the laser pulse number. The different optical properties of the films such as the position of the localized surface plasmon resonance absorption peak red shifts with increasing the laser pulse number. We performed Finite-Difference Time-Domain calculations to gain insight on how the surface nanostructure of the film affects its optical properties at the macroscale. Results indicate that the strongest localization of the electromagnetic field, and hence the strongest SERS enhancement, occurs at the channel-shaped gaps between adjacent metal islands.Larger enhancements are found in coincidence with narrower and deeper gaps. The number distribution of SERS active sites as a function of the calculated SERS enhancement factors, whose values range between 104 and 105, were obtained. Since the inter-island channels are randomly oriented they show no orientation dependence for linearly polarized radiation on a length scale larger than the typical size of the nanostructures, while larger enhancements were observed for circular polarization.

Previous reports clearly suggest that IL-17 have important role in development of systemic and peripheral inflammation in early miscarriage (EM). In the present study, we have investigated the association between genetic variants in IL-17A, IL-17F and susceptibility to EM. We recruited 135 EM patients and 150 controls and used PCR-RFLP method for genotyping the polymorphisms of IL-17A, rs4711998 (−832 A/G), rs8193036 (−692C/T) and IL-17F rs763780 (7488 T/C). No significant difference was observed for all the three polymorphic sites between the EM patients and control group in terms of genotypic (rs4711998, χ2 = 1.95, p = 0.37; rs8193036, χ2 = 1.91, p = 0.38; rs763780, χ2 = 2.45, p = 0.29), and allelic frequencies (rs4711998, OR = 1.19, 95% CI = 0.84 to 1.67, p = 0.35; rs8193036,OR = 1.18, 95% CI = 0.58 to 2.06, p = 0.75; rs763780, OR = 1.5, 95% CI = 0.93 to 2.71, p = 0.11). Further, meta-analysis of IL-17F (rs763780) variant with EM also revealed non-significant association of IL-17F (rs763780) variant with EM in the presence of mutant genotype (CC) via random effect model (p = 0.70, OR = 1.30, 95% CI =0.33–5.11).

Surface-enhanced Raman scattering is a well-established technique for molecular detection at low concentration, which is becoming increasingly popular in the field of biotechnology and health sciences. Since the process is understood in depth, the technique is becoming reliable. In this contribution, we consider another aspect of SERS besides molecular detection, focusing on the binding mechanisms of a complex system such as a protein to the noble metal substrates required by the technique itself. We also show that using a solid nanostructured substrate produced by controlled pulsed laser deposition SERS enables label-free detection of a protein. This is checked on lysozyme as a well-known prototype. Use of solid substrates with controlled morphology proves advantageous over colloidal systems for SERS applications. Moreover, such substrates are superior in terms of shelf life, packaging and ease of shipment.

We present scanning near-field images of surface plasmon modes around a single elliptical nanohole in 88 nm thick Au film. We find that rotating surface plasmon vortex modes carrying extrinsic orbital angular momentum can be induced under linearly polarized illumination. The vortex modes are obtained only when the incident polarization direction differs from one of the ellipse axes. Such a direct observation of the vortex modes is possible thanks to the ability of the SNOM technique to obtain information on both the amplitude and the phase of the near field. The presence of the vortex mode is determined by the rotational symmetry breaking of the system and it can be considered the counterpart of the photonic spin Hall effect. Finite element method calculations show that such a vorticity originates from the presence of nodal points where the phase of the field is undefined, leading to a circulation of the energy flow. The configuration producing vortex modes corresponds to a nonzero total topological charge (+1).

// Stephanie Blockhuys 1, 3 , Na Liu 1 , Nisha Rani Agarwal 3 , Annika Enejder 3 , Vesa Loitto 2 , Xiao-Feng Sun 1 1 Department of Oncology and Department of Clinical and Experimental Medicine, Linkoping University, Linkoping, Sweden 2 Medical Microbiology, Department of Clinical and Experimental Medicine, Linkoping University, Linkoping, Sweden 3 Molecular Microscopy, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden Correspondence to: Xiao-Feng Sun, email: xiao-feng.sun@liu.se Stephanie Blockhuys, email: steblo@chalmers.se Keywords: collagen type 1, colorectal cancer, X-radiation, cell migration, integrin β1 Received: March 17, 2016 Accepted: September 13, 2016 Published: September 19, 2016 ABSTRACT Rectal cancer treatment still fails with local and distant relapses of the disease. It is hypothesized that radiotherapy could stimulate cancer cell dissemination and metastasis. In this study, we evaluated the effect of X-radiation on collagen type I strap formation potential, i.e. matrix remodeling associated with mesenchymal cell migration, and behaviors of SW480, SW620, HCT116 p53 +/+ and HCT116 p53 −/− colon cancer cells. We determined a radiation-induced increase in collagen type I strap formation and migration potentials of SW480 and HCT116 p53 +/+ . Further studies with HCT116 p53 +/+ , indicated that after X-radiation strap forming cells have an increased motility. More, we detected a decrease in adhesion potential and mature integrin β1 expression, but no change in non-muscle myosin II expression for HCT116 p53 +/+ after X-radiation. Integrin β1 neutralization resulted in a decreased cell adhesion and collagen type I strap formation in both sham and X-radiated conditions. Our study indicates collagen type I strap formation as a potential mechanism of colon cancer cells with increased migration potential after X-radiation, and suggests that other molecules than integrin β1 and non-muscle myosin II are responsible for the radiation-induced collagen type I strap formation potential of colon cancer cells. This work encourages further molecular investigation of radiation-induced migration to improve rectal cancer treatment outcome.

We present the experimental determination of the vibrational contribution to molecular second hyperpolarizability (γvib) of very long polyynes that have been recently made available thanks to progress in chemical synthesis. Based on a simple theoretical model, the available experimental data allow estimating the asymptotic behavior of the vibrational contribution to molecular hyperpolarizability for increasing chain length.

Background: Cervical cancer still remains a leading cause of morbidity and mortality among women worldwide. Despite attempts to increase screening over the past several decades, incidence and mortality rates of cancer cervix have not shown substantial reduction. The conventional method of screening by cervical cytology/pap smear has failed to reduce the disease burden due to lack of patient compliance for repeated testing and a relatively sophisticated infrastructure. Therefore, alternative methods such as visual inspection after application of acetic acid (VIA), visual inspection with Lugol's Iodine (VILI) and human papillomavirus (HPV) DNA testing have been developed. The aim of present study was to compare Pap smear and VIA and evaluate their usefulness as tools for screening of premalignant and malignant lesions of cervix. Methods: This was a crossectional study over 5 months from 1 Jan 2015 to 31 may 2015 in which 212 patients attending the obstetrics and gynecology department, BHU were enrolled. Pap smear was taken followed by VIA. Pap smears were sent to pathology department, BHU where they were reported as per Bethesda System, 2001. Cervical biopsies were done in positive cases. Data obtained and statistically analyzed. Results: The present study was conducted over a period of 6 months among 212 patients age of 18-60 years screened. Positive results obtained from cytology were 26, VIA was positive in 28 women. Cervical biopsy was done in 34 women who had positive results by either test. Histology in 31 cases was suggestive of cervical intraepithelial carcinoma (CIN). Conclusions: VIA, though less specific has comparable sensitivity to Pap smear and may be used as a primary screening tool for cervical cancer. In combination both the tests have a higher predictive accuracy.

Rectal cancer is treated with preoperative radiotherapy (RT) to downstage the tumor, reduce local recurrence, and improve patient survival. Still, the treatment outcome varies significantly and new biomarkers are desired. Collagen I (Col-I) is a potential biomarker, which can be visualized label-free by second harmonic generation (SHG). Here, we used SHG to identify Col-I changes induced by RT in surgical tissue, with the aim to evaluate the clinical significance of RT-induced Col-I changes. First, we established a procedure for quantitative evaluation of Col-I by SHG in CDX2-stained tissue sections. Next, we evaluated Col-I properties in material from 31 non-RT and 29 RT rectal cancer patients. We discovered that the Col-I intensity and anisotropy were higher in the tumor invasive margin than in the inner tumor and normal mucosa, and RT increased and decreased the intensity in inner tumor and normal mucosa, respectively. Furthermore, higher Col-I intensity in the inner tumor was related to increased distant recurrence in the non-RT group but to longer survival in the RT group. In conclusion, we present a new application of SHG for quantitative analysis of Col-I in surgical material, and the first data suggest Col-I intensity as a putative prognostic biomarker in rectal cancer.

The spontaneous organization on a substrate of nanoparticles (NPs) nucleated in a laser-generated plasma results in self-assembling due to both direct specific interactions and to indirect ambient-mediated ones. A number of well-differentiated film morphologies are observed, from isolated NPs to percolated island structures. The distribution of the width of gaps between NPs, or islands formed upon NP coalescence in two representative percolated Au films, is lognormal, indicating that the growth process is random. A finer inspection of similar surface morphologies allows to correlate regularity in gap sizes and surface coverage to differences in film performance as substrates for surface-enhanced Raman spectroscopy.

Symmetrically and unsymmetrically endcapped polyynes (triisopropylsilyl – TIPS – and super trityl endcapping groups) have been studied with density functional theory calculations and Raman and infrared spectroscopy. This spectroscopic investigation provides general guidelines for studying the vibrational and structural features of sp-carbon-based materials, which nowadays are at the center of growing interest for the potential applications of nanostructured carbon materials in molecular electronics. On the basis of the description of CC stretching modes of polyynes in terms of longitudinal optical phonons of the parent infinite sp-carbon chain, we have carried out the complete assignment of the observed infrared and Raman features in the 2300–1900 cm−1 range, for chain lengths in the range 4–20 triple bonds. This allows demonstration of polarization effects induced by an unsymmetric structure and deviations from chain linearity in long polyynes. Copyright © 2013 John Wiley & Sons, Ltd.

Two different surface enhanced Raman scattering (SERS) sensors are described, tested and compared against the detection of 2-naphthalenethiol (2NPT, a volatile compound) in both solution state as well as vapor phase. The first sensor is based on an optical fiber properly modeled to induce the adhesion of colloidal Ag nanoparticles on its surface. Excitation and detection of the Raman signal is performed through the optical fiber that can be used as in situ probe for the detection of molecules adsorbed on the SERS sensitized surface. The second SERS sensor is based on nanostructured substrates consisting of Au nanoparticles produced by pulsed laser deposition in presence of a controlled Ar atmosphere. Details at the nanometer scale were observed by SEM and TEM imaging to understand the size and structure of the islands formed as a function of deposition parameters that were selected in order to maximize their SERS response. The sensitivity of the substrates to volatile species was tested by letting evaporate controlled drops of a methanol solution of 2NPT in a chamber of known volume, where the substrate was placed. After complete evaporation of the drops, this provided an in-situ environment suitable for vapor phase measurements at known concentration. SERS spectra were collected after exposing the substrates to the environment within the chamber (vapor phase measurements) or dipping them in a solution for condensed state measurements. The complete absence of the SH stretching peak in the SERS spectra proves the covalent bonding of 2NPT to the metal substrates via the sulfur atom. DFT calculations, including metal-sulfur interaction, provide a good description of the observed SERS spectra. The reported data allow concluding that our SERS substrates are suitable for detection of volatile compounds. (C) 2016 Elsevier B.V. All rights reserved.

Elemental and compound nanoparticles (NPs) are increasingly attractive due to their peculiar physico-chemical properties. Any large scale application of NPs requires a strict control on their synthesis and self-assembling. Inherent to the synthesis stage is the control of size, shape, composition, structure of the single NP. When NPs self-assemble on a suitable substrate the morphology and nanostructure of the NP architecture are the key parameters driving the performance of the resulting artificial surface. Pulsed laser ablation allows to pursue the above goals under different conditions including nanosecond and ultra-short femtosecond laser pulses, as well as an ambient fluid, either a gas at high pressure, or a radiation transparent liquid, besides vacuum. In this chapter we offer an outline of the mechanisms underlying NP synthesis in the above environments and of the most popular models currently recognized in the literature to interpret observed experi- mental trends. Concerning plasma plume propagation through an ambient gas attention is focused on the prediction versus observation of the size of isolated NPs and on a critical discussion of the morphology--properties relationship of noble metal NP arrays, considering their optical properties in the frame of enhanced vibrational spectroscopies (SERS). Ablation in a liquid of a solid target leads to a chemically stable suspension of different nanostructures in a one-step, environment friendly, clean process. For noble metal NPs the effect of liquid layer thickness and laser spot diameter on the concentration, size distribution and mutual aggregation of the produced NPs is discussed in relation to a more general picture of the process. Irradiation under vacuum with ultra-short fs laser pulses is a clean physical method to synthesize NPs; indeed in the majority of materials, random stackings of NPs, whose size ranges between 10 and 100 nm constitute the deposited film. Selected experiments on NP synthesis upon fs ablation of mainly elemental targets are reviewed focusing mainly on the features of the expanding plasma and on estab- lished mechanisms of NP synthesis. Possible lines of future development in the field are envisaged.

Barium nitrate acts as an efficient catalyst for the three-component one pot synthesis of 1,4-dihydropyridines. Barium nitrate is a safe chemical, and reaction without the use of organic solvents makes the process eco-friendly.

The Raman optical activity (ROA) spectra of both enantiomers of 2-Br-hexahelicene in chloroform solution have been measured in the range 1700-300 cm(-1). Density functional theory (DFT) calculations accurately reproduce the observed features. The most intense ROA features are also the most intense Raman features, in the region 1350-1400 cm(-1), and correspond to the so-called D-modes, which play a major role in coronene and other PAHs (polycyclic aromatic hydrocarbons). Together with a detailed analysis of the normal mode structure, the polarizability tensors for the intense Raman features are investigated and related to the principal characteristics of helicene systems, namely, chirality and π-conjugation. Through electron-phonon coupling analysis, we propose a mechanism that justifies the intense ROA signals.

A method for the growth of films consisting of Nanoparticles (NP) of Ag and Au is presented. Nanostructured films were obtained by means of nanosecond pulsed laser ablation of a metallic target in presence of a controlled Ar atmosphere. The morphology of these films from island structures to isolated nanoparticles, measured by SEM, depends on the varying gas pressure (10-100 Pa) and on the number of laser pulses (500-30000), keeping other deposition parameters such as the target to substrate distance, incidence angle, laser wavelength, laser fluence constant. Fast imaging of the plasma, performed using a intensified and gateable CCD camera at different time delays with respect to the arrival of the laser pulse, allows revelation of the propagation regime of the ablation plume and inference of plasma initial velocity. This data along with the measured average ablated mass per pulse were taken as inputs to a model to estimate the average size of NPs grown in the expanding plume. The theoretical NP sizes were compared with sizes measured from TEM images. These images indicate narrow gradients of NP sizes. Hence strict control of growth parameters aids fine tuning of NP size that is essential for many applications, including Surface Enhanced Raman Spectroscopy (SERS) active substrates. UV-Visible Spectroscopy helped in determination of appropriate laser wavelength for resonant excitation of the localized surface plasmon. SERS Spectra obtained with increasingly lower concentrations of reference dye Rhodamin 6G (Rh6G) and medical drug Apomorphine, are discussed as a perspective of application to biomedical sensors. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Barium nitrate acts as an efficient catalyst for the three-component one pot synthesis of 1,4-dihydropyridines. Barium nitrate is a safe chemical, and reaction without the use of organic solvents makes the process eco-friendly.

One of the earliest pathological hallmarks of Alzheimer's disease is the formation of soluble β-amyloid (Aβ) oligomers, also believed to be the primary neurotoxic agents long before the accumulation of amyloid plaques. However, the mechanisms by which the Aβ oligomers cause cell dysfunction and eventually cell death are poorly understood. The yeast Saccharomyces cerevisiae has here emerged as a valuable model for systemic studies of the intracellular cytotoxicity of Aβ species, revealing that Aβ transits through the different endocytic compartments and disrupts cell-, mitochondrial-, lysosomal- and ER membranes (for a review of the different aspects of amyloid-membrane interactions) finally activating the mitochondrial apoptotic pathway. In order to form a deeper understanding for the cause and consequences of mitochondrial damage, seemingly one of the central cytotoxic mechanisms, we have done a multi-parametric study on living GFP-Aβ42 expressing yeast using nonlinear microscopy. The intracellular distribution of GFP-labelled Aβ42 was correlated with the corresponding distribution and morphology of mitotracker-labelled mitochondria by means of 2-photon fluorescence microscopy. Furthermore, the consequences of the dysfunctional mitochondria and the resulting oxidative stress were visualized by the monitoring of the general NADH levels based on their 2-photon-excited intrinsic fluorescence and the content and distribution/morphology of lipid stores by means of CARS microscopy (probing natural carbon-hydrogen vibrations). We could observe how Aβ-expressing yeast accumulates significant amounts of lipid stores and follow their coalescence to larger store units, which can be recognized as a general stress response, in this case most likely due to oxidative stress.