Confocal Raman Microspectroscopy Research Articles

Characterization of Unplasticized Polyvinyl Chloride Windows by Confocal Raman Microspectroscopy and Chemometrics

In order to nondestructively and accurately identify unplasticized polyvinyl chloride windows, a classification method based on multi-feature algorithm selection modeling was developed. Confocal Raman microspectroscopy was used to obtain the spectral profiles of 150 samples from five brands. The differences in model recognition accuracy were compared among three preprocessing methods: Savitzky-Golay filtering, Hilbert transform, and wavelet transform. The best preprocessing method was selected, and the competitive adaptive reweighted sampling was used to extract feature wavelengths. Furthermore, a Bayesian classification model was constructed to classify and differentiate each sample. The results showed that confocal Raman microspectroscopy can reflect the differences in physicochemical information among different samples. Preprocessing can improve the model’s recognition accuracy, with wavelet transform (96%) > Hilbert transform (90%) > Savitzky-Golay filtering (76%) > untreated (72%). Wavelet transform can remove noise from spectral data without changing the peak region and its absorbance. Based on wavelet transform processing and competitive adaptive reweighted sampling (CARS) combined with Bayesian discriminant analysis, a 100% accurate classification of 150 samples was successfully achieved.

Impact of a conditioning step during the treatment of wood with melamine-formaldehyde resin on dimensional stabilisation

Abstract The dimensional stabilisation of wood using thermosetting resins relies on the resin uptake into the cell walls. This study tested if a conditioning step after the impregnation and before the final heat-curing enhances the cell wall uptake to improve dimensional stabilisation without increasing the chemical consumption. Small blocks of Scots pine sapwood were vacuum-impregnated with an aqueous melamine formaldehyde solution and conditioned at 33, 70, or 95 % RH for up to 1 week before drying and curing the blocks at 103 °C. However, the conditioning step decreased the cell wall bulking and the moisture exclusion effect compared to the immediate heat curing of the impregnated samples. Analyses of the resin-treated samples by scanning electron microscopy, IR spectroscopy and confocal Raman microspectroscopy provided evidence of wood hydrolysis and polycondensation of the resin within the cell lumen during the conditioning step. Hydrolysis and removal of wood constituents may have counterbalanced the cell wall bulking of the resin. Polycondensation of the resin in the lumen increased its molecule size, which could have hindered the cell wall diffusion of the resin.

Beadlet anemone: A novel bio-indicator of microplastic pollution in the marine environment

Extensive usage of plastic in different industries and household usage has degraded to microplastic due to environmental conditions over the last year. While several researchers conducted the determination of microplastic (MP) bioaccumulation from rivers to stormwater, except for some filter-feeding species used as a bioindicator, to achieve a holistic approach to the fate of MPs in the marine system, sea anemone was used as an indicator. Microplastics were extracted from surface seawater, sediment, and sea anemones from the same sampling area and characterized. The extracted MPs were confirmed by confocal micro-Raman spectroscopy, and the morphology of the MPs was investigated by scanning electron microscopy (SEM). The results showed that the accumulation of microplastics and the type of polymer, shape, colour, and size of these persistent pollutants varied in sediment, surface water, and sea anemone. The abundance of MPs was different, and grey-coloured MPs were detected at a relatively higher level in sea anemones, from 8.7 to 13.3%, and more minor MPs (less than 0.5 mm) at 43.4–56.8% were detected in sea anemones among the sampling stations. In terms of polymer type, there are relatively more types of polymers classified in sea anemones among the sampling stations (six different types of polymers). These results indicated that the utilization of sea anemones as a bioindicator for MPs could be a critical factor in a better understanding of their pathway in the marine ecosystem. This study proved that analysing sea anemones as an indicator could offer a reliable, fast, and time-saving approach for detecting microplastic accumulation in marine systems.

Improvement of in vitro digestibility and thermostability of debranched waxy maize starch by sequential ethanol fractionation

This study aimed to improve the in vitro digestibility and thermostability of debranched waxy maize starch (DWMS) by sequential fractionation. Waxy maize starch was debranched by pullulanase, followed by sequential precipitation through controlling the ratio of starch supernatants to ethanol at 1:0.5, 1:1, and 1:1.5 (v/v). Subsequently the structural, thermal, in vitro digestive properties of DWMS were investigated. In vitro digestion results showed that the secondary ethanol fractionation of 1:1 on the basis of the initial fractionation (1:0.5) induced a significant higher amount of slowly digestive starch (SDS, 30.0 %) and resistant starch (RS, 58.6 %) amongst all three fractions, along with the highest peak temperature (Tp, 106.4 °C) and the highest decomposition value (Td, 310.0 °C) in calorimetric (DSC) and thermogravimetry (TGA) measurements. Chain length distribution, surface morphology, and laser confocal micro-Raman spectroscopy (LCM-Raman) analyses revealed that medium (degree of polymerization, DP 13– 36) and long chains (DP ≥37) respectively constituting 72.0 % and 10.2 % of DWMS resulted in the formation of spheroidal crystallites with higher homogeneity and more ordered short-range structures. Overall, this work confirmed that ethanol fractionation is an efficient method for improving the in vitro digestibility and heat stability of waxy maize starch.

Impact of e-cigarette liquid on porcine lung tissue - ex vivo confocal Raman micro-spectroscopy study.

Ex vivo porcine lung immersed in e-liquid was investigated in-depth using confocal Raman micro-spectroscopy to assess the e-liquid influence on the lung. It was found that lung-related Raman band intensities at 1002, 1548, 1618 and 1655 cm-1 increased after first and second treatments except the surface, which was attributed to the well-known optical clearing effect due to alveoli filling with e-liquid resulting in light scattering reduction. The autofluorescence enhancement was explained by oxidative stress induced in lung during exposure to e-liquid. Moreover, e-liquid induced collagen dehydration was revealed by the I937 /I926 Raman band intensity ratio change. The effect was enhanced after the second treatment of the same lung tissue that indicates the possibility of multi-step OC treatment. We hypothesize that the nicotine-flavour free e-liquids containing glycerol and propylene glycol could potentially be used in clinical protocols as optical clearing agent for enhanced in-depth Raman-guided bronchoscopy. This article is protected by copyright. All rights reserved.

Multi-analytical investigation into the materials and techniques of paintings on Northern Wei Dynasty (398–494 CE) coffin planks excavated from Shanxi, China

This study combined various non-invasive and micro-invasive analytical techniques to investigate the production process of coffin plank paintings excavated from a Northern Wei tomb in Zhijiabao Village, Datong City, Shanxi Province. Fiber-optic reflectance spectroscopy, portable Raman spectroscopy, and portable X-ray fluorescence spectroscopy were employed for in-situ non-invasive detection of coffin panel paintings. On that basis, micro-samples in smaller amounts than that of previous studies of the same type were collected and analyzed through optical microscopy, confocal micro-Raman spectroscopy, and scanning electron microscopy-energy dispersive spectroscopy. The results showed that the studied coffin plank decoration was painted after applying a layer of yellow primer to the plank surface. Specifically, cinnabar was used as the red material, pararealgar was used as the yellow color, an indigo and orpiment mixture was used as the green substance, the blue pigment was most likely an indigo and lead white mixture, gypsum was used the white material, and carbon black was used as the black pigment. Notably, the studied coffin plank was painted with a mixture of inorganic and organic materials to present the green and blue colors. This study provided not only a scientific basis for the conservation and restoration of this artifact but also new information for the research on Northern Wei art history.

Multispectral Raman Differentiation of Malignant Skin Neoplasms In Vitro: Search for Specific Biomarkers and Optimal Wavelengths.

Confocal scanning Raman and photoluminescence (PL) microspectroscopy is a structure-sensitive optical method that allows the non-invasive analysis of biomarkers in the skin tissue. We used it to perform in vitro diagnostics of different malignant skin neoplasms at several excitation wavelengths (532, 785 and 1064 nm). Distinct spectral differences were noticed in the Raman spectra of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), compared with healthy skin. Our analysis of Raman/PL spectra at the different excitation wavelengths enabled us to propose two novel wavelength-independent spectral criteria (intensity ratios for 1302 cm-1 and 1445 cm-1 bands, 1745 cm-1 and 1445 cm-1 bands), related to the different vibrational "fingerprints" of cell membrane lipids as biomarkers, which was confirmed by the multivariate curve resolution (MCR) technique. These criteria allowed us to differentiate healthy skin from BCC and SCC with sensitivity and specificity higher than 95%, demonstrating high clinical importance in the differential diagnostics of skin tumors.

Atopic Dermatitis: Molecular Alterations between Lesional and Non-Lesional Skin Determined Noninvasively by In Vivo Confocal Raman Microspectroscopy.

Atopic dermatitis (AD)/atopic eczema is a chronic relapsing inflammatory skin disease affecting nearly 14% of the adult population. An important pathogenetic pillar in AD is the disrupted skin barrier function (SBF). The atopic stratum corneum (SC) has been examined using several methods, including Raman microspectroscopy, yet so far, there is no depth-dependent analysis over the entire SC thickness. Therefore, we recruited 21 AD patients (9 female, 12 male) and compared the lesional (LAS) with non-lesional atopic skin (nLAS) in vivo with confocal Raman microspectroscopy. Our results demonstrated decreased total intercellular lipid and carotenoid concentrations, as well as a shift towards decreased orthorhombic lateral lipid organisation in LAS. Further, we observed a lower concentration of natural moisturising factor (NMF) and a trend towards increased strongly bound and decreased weakly bound water in LAS. Finally, LAS showed an altered secondary and tertiary keratin structure, demonstrating a more folded keratin state than nLAS. The obtained results are discussed in comparison with healthy skin and yield detailed insights into the atopic SC structure. LAS clearly shows molecular alterations at certain SC depths compared with nLAS which imply a reduced SBF. A thorough understanding of these alterations provides useful information on the aetiology of AD and for the development/control of targeted topical therapies.

Optical Methods for Non-Invasive Determination of Skin Penetration: Current Trends, Advances, Possibilities, Prospects, and Translation into In Vivo Human Studies.

Information on the penetration depth, pathways, metabolization, storage of vehicles, active pharmaceutical ingredients (APIs), and functional cosmetic ingredients (FCIs) of topically applied formulations or contaminants (substances) in skin is of great importance for understanding their interaction with skin targets, treatment efficacy, and risk assessment-a challenging task in dermatology, cosmetology, and pharmacy. Non-invasive methods for the qualitative and quantitative visualization of substances in skin in vivo are favored and limited to optical imaging and spectroscopic methods such as fluorescence/reflectance confocal laser scanning microscopy (CLSM); two-photon tomography (2PT) combined with autofluorescence (2PT-AF), fluorescence lifetime imaging (2PT-FLIM), second-harmonic generation (SHG), coherent anti-Stokes Raman scattering (CARS), and reflectance confocal microscopy (2PT-RCM); three-photon tomography (3PT); confocal Raman micro-spectroscopy (CRM); surface-enhanced Raman scattering (SERS) micro-spectroscopy; stimulated Raman scattering (SRS) microscopy; and optical coherence tomography (OCT). This review summarizes the state of the art in the use of the CLSM, 2PT, 3PT, CRM, SERS, SRS, and OCT optical methods to study skin penetration in vivo non-invasively (302 references). The advantages, limitations, possibilities, and prospects of the reviewed optical methods are comprehensively discussed. The ex vivo studies discussed are potentially translatable into in vivo measurements. The requirements for the optical properties of substances to determine their penetration into skin by certain methods are highlighted.

Topical dexpanthenol effects on physiological parameters of the stratum corneum by Confocal Raman Microspectroscopy.

Topical use of dexpanthenol presents well-established moisturizing properties and maintenance and repair of the skin barrier function, however, its exact action mechanisms are not completely elucidated. In this context, Confocal Raman Microspectroscopy is an optical method that enables non-invasive and non-destructive in vivo analysis with the sensitive acquisition of molecular changes in different skin layers. Herein, the aim was to evaluate the effects of topical dexpanthenol on the components and physiological parameters of the stratum corneum (SC). Ten healthy female subjects underwent skin evaluation by means of a Confocal Raman Spectrometer Skin Analyzer 3510. Spectral data were obtained from the skin of the anterior forearm region, before and 2h after applying a cosmetic formulation containing or not containing 5% dexpanthenol. Semiquantitative analysis of the natural moisturizing factor showed a significant decrease in content after 2 h of topical dexpanthenol application, while the analysis of the lamellar organization of intercellular lipids and the secondary structure of keratin showed a significant increase in hexagonal organization of lipids at the first half of the SC and a significant increase in β-pleated sheet conformation of keratin. Effects of topical dexpanthenol on SC suggest a contribution in increasing fluidity of both lipidic and protein components of the SC and are compatible with dexpanthenol activity in maintaining adequate physiological conditions and preventing transepidermal water loss. This study also contributes to the elucidation of action mechanisms and other concurrent biochemical processes.

Rapid identification of micro and nanoplastics by line scan Raman micro-spectroscopy

Microplastic pollution has become an environmental problem that cannot be ignored in our society. Raman spectroscopy technology has been widely used in the field of microplastics detection due to its non-contact, non-destructive chemical specificity. Traditional point confocal Raman micro-spectroscopy technology uses single-point detection, resulting in long measurement times to scan the large areas of interest of typical samples. In this paper, we present a line scan confocal Raman micro-spectroscopy tool for fast detection and identification of microplastic particles. We show size and composition identification of particles and imaging over large areas. Compared with point confocal Raman imaging, the line scan confocal Raman technology increases the imaging speed by 1–2 orders of magnitude.

Altered structure indicating reduced barrier function of lesional compared to non-lesional psoriatic skin-A non-invasive in vivo study of the human stratum corneum with confocal Raman micro-spectroscopy.

Psoriasis, one of the most common skin diseases affecting roughly 2%-3% of the world population, is associated with a reduced skin barrier function (SBF) that might play an important role in its pathophysiology. The SBF is provided primarily by the stratum corneum (SC) of the skin. Previous studies have revealed a higher trans-epidermal water loss, lower hydration, abnormal concentration and composition of intercellular lipids, as well as alterations in secondary keratin structure in the psoriatic SC. We compared on molecular level lesional psoriatic skin (LPS) with non-lesional psoriatic skin (nLPS) from 19 patients non-invasively in vivo, using confocal Raman micro-spectroscopy. By analysing the corresponding Raman spectra, we determined SBF-defining parameters of the SC depth-dependently. Our results revealed a lower total lipid concentration, a shift of lamellar lipid organisation towards more gauche-conformers and an increase of the less dense hexagonal lateral packing of the intercellular lipids in LPS. Furthermore, we observed lower natural moisturising factor concentration, lower total water as well as a strong tendency towards less strongly bound and more weakly bound water molecules in LPS. Finally, we detected a less stable secondary keratin structure with increased β-sheets, in contrast to the tertiary structure, showing a higher degree of folded keratin in LPS. These findings clearly suggest structural differences indicating a reduced SBF in LPS, and are discussed in juxtaposition to preceding outcomes for psoriatic and healthy skin. Understanding the alterations of the psoriatic SC provides insights into the exact pathophysiology of psoriasis and paves the way for optimal future treatments.

Tracking deuterium uptake in hydroponically grown maize roots using correlative helium ion microscopy and Raman micro-spectroscopy

BackgroundInvestigations into the growth and self-organization of plant roots is subject to fundamental and applied research in various areas such as botany, agriculture, and soil science. The growth activity of the plant tissue can be investigated by isotope labeling experiments with heavy water and subsequent detection of the deuterium in non-exchangeable positions incorporated into the plant biomass. Commonly used analytical methods to detect deuterium in plants are based on mass-spectrometry or neutron-scattering and they either suffer from elaborated sample preparation, destruction of the sample during analysis, or low spatial resolution. Confocal Raman micro-spectroscopy (CRM) can be considered a promising method to overcome the aforementioned challenges. The substitution of hydrogen with deuterium results in the measurable shift of the CH-related Raman bands. By employing correlative approaches with a high-resolution technique, such as helium ion microscopy (HIM), additional structural information can be added to CRM isotope maps and spatial resolution can be further increased. For that, it is necessary to develop a comprehensive workflow from sample preparation to data processing.ResultsA workflow to prepare and analyze roots of hydroponically grown and deuterium labeled Zea mays by correlative HIM-CRM micro-analysis was developed. The accuracy and linearity of deuterium detection by CRM were tested and confirmed with samples of deuterated glucose. A set of root samples taken from deuterated Zea mays in a time-series experiment was used to test the entire workflow. The deuterium content in the roots measured by CRM was close to the values obtained by isotope-ratio mass spectrometry. As expected, root tips being the most actively growing root zone had incorporated the highest amount of deuterium which increased with increasing time of labeling. Furthermore, correlative HIM-CRM analysis allowed for obtaining the spatial distribution pattern of deuterium and lignin in root cross-sections. Here, more active root zones with higher deuterium incorporation showed less lignification.ConclusionsWe demonstrated that CRM in combination with deuterium labeling can be an alternative and reliable tool for the analysis of plant growth. This approach together with the developed workflow has the potential to be extended to complex systems such as plant roots grown in soil.

Area-Selective Depolymerization of Hydroxycinnamates Visualized by Raman Imaging in Miscanthus sinensis cv. Cell Wall.

Lignin-carbohydrate complexes (LCCs) are regarded as a barrier for lignocellulosic biomass refinery. Here, confocal Raman microspectroscopy has been used to visualize the dissolution of hydroxycinnamates (HCMs) incorporated into LCCs by ether and ester bonds for energy crops Miscanthus sinensis cv. during successive NaOH (2.5% w/w) treatment. Raman spectral analysis indicated that mild NaOH treatment resulted in a higher proportion of HCM depolymerization in highly lignified middle lamella areas (>66.0%) than carbohydrate-abundant secondary walls. Furthermore, Raman imaging revealed preferential depolymerization of lignin from the sclerenchyma fiber (Sf) and parenchyma (Par) secondary wall with an increment of treatment time from 0 to 25 min, while middle lamella areas of Sf and Par were less affected where the depolymerization of HCMs was closely related with that of lignin (coefficient factors > 0.96). A better understanding of the depolymerization behavior for HCMs accompanied by lignin depolymerization was important to break LCC bonds in herbaceous biomass efficiently.

Non-Destructive Monitoring of the Ripening of Plums Using Confocal Micro-Raman and Laser Induced Fluorescence Spectroscopy

Plums are nutraceutically rich and have health-promoting properties. To produce high-quality fruits, it is important to monitor them at harvest. This study illustrates the potential of nondestructive laser-induced fluorescence and confocal micro Raman spectroscopy for monitoring the ripening of plums. The fluorescence profile indicates that as fruit ripens, the intensity of the fluorescence of chlorophyll at 685 and 730 nm decreases with increase in the intensity ratio (F685/F730) of these bands. These observations reveal that as fruit ripens, there is a gradual loss of chlorophyll. In order to get further insight into pigment dynamics, the Raman spectra of the fruit were analyzed. The Raman spectra of pre and post-ripe stages of fruits show that as the fruit ripens, there is a prominent increase in the intensity of anthocyanin bands accompanied by subsequent decrease in the intensity of the carotenoid bands. The spectral analysis reveals that the ripening is associated with a decrease in the chlorophyll and carotenoid content with subsequent increase in anthocyanins. The results of this study highlight the utility of laser-induced fluorescence and confocal micro-Raman spectroscopy for the rapid, sensitive, and nondestructive monitoring of plum ripening.

Directional assessment of the skin barrier function in vivo.

The fundamental function of the epidermis is to provide an inside-out barrier to water loss and an outside-in barrier to penetration of external irritants. Transepidermal water loss (TEWL) has been extensively used as a method of estimating the skin barrier quality, typically without any consideration of directionality. The validity of TEWL as an estimate of skin permeability to external substances has been controversial in vitro and in vivo. The aim of this work was to assess the relationship between TEWL and the penetration of a topically applied external marker (caffeine) in healthy skin in vivo before and following a challenge to the barrier. The skin barrier was challenged by application of aqueous solutions of mild cleanser products under occlusion for 3h on the forearms of nine human participants. Skin barrier quality was evaluated before and after the challenge by measuring the TEWL rate and the permeated amount of topically applied caffeine using in vivo confocal Raman microspectroscopy. No skin irritation was observed following the skin barrier challenge. TEWL rates and the caffeine penetrated amount in the stratum corneum after the challenge were not correlated. A weak correlation was observed when the changes were corrected to water-only treatment. TEWL values can be influenced by environmental conditions as well as the skin temperature and water content. Measuring TEWL rates is not always representative of the outside-in barrier. TEWL may be useful in differentiating large changes in skin barrier function (e.g., between healthy and compromised skin) but is less sensitive to small variations following topical application of mild cleansers.

Red- and Near-Infrared-Excited Autofluorescence as a Marker for Acute Oxidative Stress in Skin Exposed to Cigarette Smoke Ex Vivo and In Vivo.

Air pollution is increasing worldwide and skin is exposed to high levels of pollution daily, causing oxidative stress and other negative consequences. The methods used to determine oxidative stress in the skin are invasive and non-invasive label-free in vivo methods, which are severely limited. Here, a non-invasive and label-free method to determine the effect of cigarette smoke (CS) exposure on skin ex vivo (porcine) and in vivo (human) was established. The method is based on the measurement of significant CS-exposure-induced enhancement in red- and near-infrared (NIR)-excited autofluorescence (AF) intensities in the skin. To understand the origin of red- and NIR-excited skin AF, the skin was exposed to several doses of CS in a smoking chamber. UVA irradiation was used as a positive control of oxidative stress in the skin. The skin was measured with confocal Raman microspectroscopy before CS exposure, immediately after CS exposure, and after skin cleaning. CS exposure significantly increased the intensity of red- and NIR-excited skin AF in a dose-dependent manner in the epidermis, as confirmed by laser scanning microscopy AF imaging and fluorescence spectroscopy measurements. UVA irradiation enhanced the intensity of AF, but to a lower extent than CS exposure. We concluded that the increase in red- and NIR-excited AF intensities of the skin after CS exposure could clearly be related to the induction of oxidative stress in skin, where skin surface lipids are mainly oxidized.

Confocal Raman microspectroscopy combined with spectral screening algorithms for quantitative analysis of starch in rice

Starch is one of the main components of rice. The feasibility of confocal Raman microspectroscopy (CRM) combined with spectral screening algorithms for quantitative detection of starch in rice was investigated in this paper. Firstly, the Raman spectra of the samples were processed by pre-processing and spectral screening algorithm of the data. Secondly, the quantitative starch detection models were respectively established by correction set by partial least squares regression, particle swarm optimization-support vector regression, gray wolf optimizer-support vector regression (GWO-SVR) as well as back propagation neural network. After that, the quantitative starch detection models were validated using the prediction set. Eventually, the related coefficient of the prediction set, root mean square error of the prediction set, and mean relative error of GWO-SVR starch quantification detection model combined with normalization and IPLS screening were respectively 0.8915, 1.03%, and 1.08%. The experimental results manifested that the swift and precise detection of starch content in rice by CRM was workable after proper pre-processing and spectral screening algorithm.

Formation of Periodic Surface Structures by Multipulse Femtosecond Laser Processing of Au-Coated Ni in Various Fluids.

Using multipulse linearly polarized femtosecond laser processing of a Au-coated Ni surface in various liquid media created subwavelength self-organized nanoripples. The thin gold film improved the laser absorptivity, decreasing the ripple generation threshold in liquids. High spatial frequency ripples exhibited lower angular deviation than low spatial frequency ones, but in water the deviation was comparable for both types of ripples. The initiation of nanoripples may precede nanoparticle generation, which is why in hexane several cuboid Au particles were trapped between the ripples. Fast cooling processes freeze ejected molten droplets during the phase explosion and surface reorganization. Grazing incidence X-ray diffraction of samples processed in butanol showed a small shift toward smaller angles for the Ni phase, indicating a lattice expansion due to higher tensile stress. Confocal micro-Raman spectroscopy detected surface graphitization and amorphization in areas laser-treated in ethanol, butanol, and hexane, with the highest carbonization observed in butanol. Presumably, femtosecond laser-induced photolysis triggers the formation of graphite nanocrystallites, and consecutive pulses cause amorphization. Static contact angle measurements showed a general tendency toward hydrophobicity with highest contact angles for rippled areas created in butanol.

Electrostructural and morphological features of etch pits in boron-doped HPHT-diamond single crystals and multisectoral plates

Morphological, structural, and nano-electrical features of the growth defects and sectoral boundaries revealed by selective etching in synthetic boron-doped single crystals of diamond (BDD) and multisectoral plates are characterized by a set of scanning probe microscopy (SPM) methods, confocal micro-Raman, and micro-FTIR spectroscopy. Diamond single crystals were grown under high pressure and high temperature conditions (HPHT) in the FeAlBC system. Morphology of dislocation etch pits and micro-defect related pits/protrusions compared both on the growth facets and multisectoral plates cut parallel to the {110} facet of BDD single crystals. Ex situ AFM observation of the etched surface revealed non-homogeneously distributed pits and protrusions over the growth facets correlated with irregular macroscopic growth defects. There is a center-to-periphery gradient of dislocation density in multisectoral plates. The protrusions are homogeneously distributed over plates; some often decorate dislocation pits. Micro-Raman mapping on dislocation pits (boron-rich regions) decorated by low-boron content regions revealed crystalline imperfections in three dimensions, with apparent compressive/tensile strain. The defects were mainly electrically neutral under surface potential mapping by Kelvin probe force microscopy, opposite to the inter-sectoral boundaries having pronounced surface potential steps. The scanning spreading resistance microscopy shows resistivity variations at etching-reviled surface defects and sectoral boundaries if the appropriate DC bias is applied to the SPM tip.