Atomic Force Microscopy Images Research Articles

Photodiagnosis and photodynamic recognition of cervical cancer with SEM and AFM images

So far, the number of patients who die from cancer is quite high. Continuation of early detection research is important to reduce the number of deaths due to cancer. At the time of the literature review, images of the same patients taken from Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) for early diagnosis of cervix cancer have not been addressed to date. This article, Photodiagnosis and Photodynamics with SEM and AFM images are valuable in recognizing cervical cancer and starting treatment early. Simultaneous examination of the, Photodiagnosis and Photodynamics with SEM and AFM cervix images of patients will provide us with a far more powerful solution than a one-way solution. Daubechies (db2, db3, db4, and db5), Coiflet (coif5, coif4, coif3, and coif2), Symlet (sym5, sym4, sym3, and sym2), and Biorthogonal (bior1.3, bior2.8, bior1.5, and bior3.3) 16 discrete wavelet transformation families (DWTF) have been applied to AFM and SEM images. One approximate and three detail coefficients have been obtained for each one AFM and SEM cervix images. Homogeneity, contrast, angular second moment, entropy, mean, standard deviation, correlation, cluster prominence, dissimilarity, and cluster shade values have been calculated for each of these one approximate and three detail coefficients. The classification rate found by the averages of the results obtained from the DWTF_JSD, DWTF_HD and DWTF_TD algorithms for AFM and SEM cervix images are 98.29% and 97.10%, respectively. According to these results, it has been determined that SEM images have lower classification rate than AFM images. It has been also observed that the surface roughness of the mAFM images was larger than nAFM and bAFM images. But, it was observed that the volume of particles of the mAFM images has been smaller than nAFM and bAFM images.

Evaluation of Glazing and Polishing for Novel Chairside CAD/CAM Lithium Disilicate Containing Virgilite Crystals.

This comparative in vitro study evaluated surface treatment methods for chairside CAD/CAM lithium disilicate enriched with virgilite using atomic force microscopy (AFM) imaging. Specimens were fabricated from two lithium disilicate materials: the traditional material (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein) and a virgilite-containing material (CEREC Tessera, Dentsply Sirona, Charlotte, NC, USA). Surface roughness (Ra) [in micrometers (μm)] was quantitatively assessed with AFM. The results demonstrated that IPS e.max CAD with glazing exhibited the smoothest surface with the lowest Ra values (10.03 ± 5.03 μm). In contrast, CEREC Tessera exhibited the highest surface roughness when treated with glazing (51.98 ± 12.31 μm), while the zirconia polishing system provided a smoother surface (15.44 ± 9.69 μm).

Water Transport Dynamics and Kinetic Equilibria in Nanoblisters at the Graphene-Mica Interface.

Nanoscale reduced volumes with novel properties can be produced from 2D materials like graphene. Mild thermal annealing imposes vast and varied amounts of water intercalation into the graphene-mica interface, resulting in the formation of nanoblisters and impacting the local environment for applications such as reactions confined at the solid-solid interface. Atomic force microscopy imaging (AFM) and micro-Fourier transform infrared (micro-FTIR) spectroscopy characterization after 60-120 °C anneals revealed large volumes of water readily intercalate into graphene-mica nanoblisters, elucidating water transport behavior under mild reaction conditions. The inflation and deflation of graphene nanoblisters throughout the annealing process is attributed to the contraction of the graphene capping layer upon cooling from the annealing temperature, due to the independence of nanoblister aspect ratios from nanoblister volume or surface area. The intercalated water volume was estimated by the distended volumes of each nanoblister and exhibit an equilibrium trend established after 2 h of annealing. This water equilibrium occurs at a variety of temperatures, but higher temperatures favor graphene contraction and distention to accommodate larger volumes of water. Nanoblister volumes are set during the cooling process, indicating a kinetic trapping effect that can influence physical properties and reactivity for all systems confined at the graphene-mica interface.

Nanoscopic structural and optical investigations on blue InGaN single quantum wells serving as layers beneath efficient red active layers

In state-of-the-art red InGaN light-emitting diodes (LEDs), an InGaN-based blue single quantum well (SQW) is used as an underlying layer to improve the red emission efficiency. However, the role of blue SQW is not fully understood. This study investigates the structural and optical properties of blue InGaN SQW by atomic force microscopy (AFM) and photoluminescence (PL) spectroscopy under scanning near-field optical microscopy (SNOM). The AFM images reveal deep and shallow V-pits, corresponding to screw and mixed threading dislocations (TDs). The SNOM-PL intensity image illustrates that all the V-pits correspond to dark spots. We also observe dark spots not associated with the V-pits; given the correspondence between the dark spot density and the edge TD density estimated via x-ray diffraction measurement, these dark spots likely originate from edge TDs. Unlike previous studies, we find that TDs act as nonradiative recombination centers (NRCs) in recent blue SQW, most likely because of the reduction of point defects by InGaN/GaN superlattices. Edge, screw, and mixed TDs have nearly the same impact on the integrated PL intensity of the blue InGaN SQW. Given the correlation of dark emission positions between the blue and red emissions in hybrid red InGaN LEDs in our prior study, all the TDs should function as NRCs in the red emission. The comparable dark spot density between the blue and red SQW suggests that blue SQW suppresses the generation of NRCs in red SQW.

AGEing of collagen: The effects of glycation on collagen's stability, mechanics and assembly.

Advanced Glycation End Products (AGEs) are the end result of the irreversible, non-enzymatic glycation of proteins by reducing sugars. These chemical modifications accumulate with age and have been associated with various age-related and diabetic complications. AGEs predominantly accumulate on proteins with slow turnover rates, of which collagen is a prime example. Glycation has been associated with tissue stiffening and reduced collagen fibril remodelling. In this study, we investigate the effects of glycation on the stability of type I collagen, its molecular-level mechanics and its ability to perform its physiological role of self-assembly. Collagen AGEing is induced in vitro by incubation with ribose. We confirm and assess glycation using fluorescence measurements and changes in collagen's electrophoretic mobility. Susceptibility to trypsin digestion and circular dichroism (CD) spectroscopy are used to probe changes in collagen's triple helical stability, revealing decreased stability due to glycation. Atomic Force Microscopy (AFM) imaging is used to quantify how AGEing affects collagen flexibility, where we find molecular-scale stiffening. Finally we use microscopy to show that glycated collagen molecules are unable to self-assemble into fibrils. These findings shed light on the molecular mechanisms underlying AGE-induced tissue changes, offering insight into how glycation modifies protein structure and stability.

Aggregation inhibitory effect of vitamin C on cataract-associated P23T γD-crystallin.

Cataract is a progressive loss of eye lens transparency, as a result of age-related chemical modifications or due to congenital mutations in crystallins. A vital antioxidant in the aqueous humor, the vitamin C, has been suggested to hold potential for the prophylaxis of age-related cataract. However, the effect of vitamin C on congenital cataract has not yet been investigated. Here, we explored the aggregation inhibitory effect of vitamin C on the P23T human γD-crystallin mutant, associated with congenital cataract. The effect of vitamin C on the aggregation propensity of P23T human γD-crystallin was investigated by solution NMR, atomic force microscopy (AFM), and other biophysical techniques. We found that vitamin C is able to prevent and reverse P23T human γD-crystallin aggregation in a dose-dependent manner. In particular, NMR data suggest that the inhibitory effect of vitamin C on P23T human γD-crystallin phase-separation is probably mediated by interacting with aggregation prone regions. AFM images of P23T human γD-crystallin under native aggregating conditions revealed the appearance of amorphous aggregates, that disassemble into monomers in the presence of vitamin C. The current study highlights and confirms the possibility that vitamin C is able to dissolve crystallin aggregates, potentially slowing the onset or reversing cataract.

New Nanobioceramics Based on Hydroxyapatite for Biomedical Applications: Stability and Properties

In this work, we report for the first time the development and complex characterization of new bioceramics based on hydroxyapatite (HAp, Ca10(PO4)6(OH)2). On the other hand, the lyophilization process was used for the first time in this research. The samples were obtained by a modified coprecipitation method and were dried by lyophilization (lyophilized hydroxyapatite (HApLF) and lyophilized zinc-doped hydroxyapatite (5ZnHApLF)). Valuable information about the HApLF and 5ZnHApLF stability was obtained through nondestructive ultrasound measurements. The X-ray diffraction (XRD) studies revealed the phase and the effects of the incorporation of Zn ions into the HAp structure. The chemical composition of the samples was evaluated by energy dispersive X-ray analysis (EDS) and X-ray photoelectron spectroscopy (XPS). Information about the functional groups present in the HApLF and 5ZnHApLF was obtained using Fourier Transform Infrared Spectroscopy (FTIR) studies. The morphology of HApLF and 5ZnHApLF pellets was observed by scanning electron microscopy (SEM). The surface topography of HApLF and 5ZnHApLF pellets was studied with the aid of atomic force microscopy (AFM). Details regarding the roughness of the samples were also obtained using AFM topographies and SEM images. A complementary study was also carried out on a larger analysis surface using a Scanning Acoustic Microscope (SAM). The SAM was used for the first time to analyze the surface of HAp and 5ZnHAp pellets. The biological properties of the HApLF and 5ZnHApLF pellets was investigated with the aid of MG63 and human gingival fibroblasts (HGF-1) cell lines. The results of the cell viability assay highlighted that both the HApLF and 5ZnHApLF pellets exhibited good biological activity. Moreover, SEM and AFM studies were conducted in order to emphasize the development of MG63 and HGF-1 cells on the pellet’s surface. Both SEM and AFM images depicted that the pellets’ surface favored the cell attachment and development of MG63 and HGF-1 cells. Furthermore, the antimicrobial properties of the HApLF and 5ZnHApLF were evaluated against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and Candida albicans ATCC 10231. The results of the antimicrobial assays highlighted that the 5ZnHApLF exhibited a strong antimicrobial activity against the tested microbial strains. The results of the biological assays suggested that the samples show great potential for being used in the development of novel materials for biomedical applications.

Acid Pre-Treatment of Graphite Electrodes: An Alternative to Enhance the Sensing Performance of Benzenediol Isomers

Abstract Electroanalytical techniques offer several advantages, such as low cost, portability, and high analysis frequency. These benefits can be further enhanced by replacing standard electrodes (boron-doped diamond, glassy carbon, gold, platinum, etc.) with abundant, low-cost carbon materials. Pyrolytic Graphite Sheet (GS) electrodes have recently emerged as a reliable alternative, providing good stability, sensitivity, and mechanical strength. Their performance can be improved with acidic treatments. Scanning electron and atomic force microscopy images revealed irregular patterns on the edges of acid-treated GS, consistent with Raman spectra, which showed changes in the ID/IG ratio, indicating more structural defects. The acidic treatment also increased the electroactive area of GS electrodes and oxygen-containing functional groups, as observed by XPS, leading to enhanced signal currents. Additionally, electrochemical impedance spectroscopy confirmed a decrease in charge transfer resistance. Treated electrodes exhibited lower detection limits for catechol (0.58 µmol L-1) and resorcinol (0.16 µmol L-1) compared to untreated GS electrodes. The presence of potential interferents, such as KCl, NaCl, glucose, ascorbic acid, ibuprofen, paracetamol, and uric acid, did not affect the detection of catechol and resorcinol. Recovery values for spiked water samples ranged from 80% to 109%, confirming the accuracy of the proposed analytical method.

Nonlinear Harmonics: A Gateway to Enhanced Image Contrast and Material Discrimination.

Recent advancements in atomic force microscopy (AFM) have enabled detailed exploration of materials at the molecular and atomic levels. These developments, however, pose a challenge: the data generated by microscopic and spectroscopic experiments are increasing rapidly in both size and complexity. Extracting meaningful physical insights from these datasets is challenging, particularly for multilayer heterogeneous nanoscale structures. In this paper, an unsupervised approach is presented to enhance AFM image contrast by analyzing the nonlinear response of a cantilever interacting with a material's surface using a wavelet-based AFM. This method simultaneously measures different frequencies and harmonics in a single scan, without the need for additional hardware and exciting multiple cantilevers' eigenmodes. This developed AFM image contrast enhancement (AFM-ICE) approach employs unsupervised learning, image processing, and image fusion techniques. The method is applied to interpret complex multilayer structures consist of defects, deposited nanoparticles and heterogeneities. Its substantial capability is demonstrated to improve image contrast and differentiate between various components. This methodology can pave the way for rapid and precise determination of material properties with enhancedresolution.

Graphene Quantum Dots in Bacterial Cellulose Hydrogels for Visible Light-Activated Antibiofilm and Angiogenesis in Infection Management

A novel bacterial cellulose (BC)-based composite hydrogel with graphene quantum dots (BC-GQDs) was developed for photodynamic therapy using blue and green light (BC-GQD_blue and BC-GQD_green) to target pathogenic bacterial biofilms. This approach aims to address complications in treating nosocomial infections and combating multi-drug-resistant organisms. Short-term illumination (30 min) of both BC-GQD samples led to singlet oxygen production and a reduction in pathogenic biofilms. Significant antibiofilm activity (>50% reduction) was achieved against Staphylococcus aureus and Escherichia coli with BC-GQD_green, and against Pseudomonas aeruginosa with BC-GQD_blue. Atomic force microscopy images revealed a substantial decrease in biofilm mass, accompanied by changes in surface roughness and area, further confirming the antibiofilm efficacy of BC-GQDs under blue and green light, without any observed chemical alterations. Additionally, the biocompatibility of BC-GQDs was demonstrated with human gingival fibroblasts (HGFs). For the first time, in vitro studies explored the visible light-induced potential of BC-GQD composites to promote wound healing processes, showing increased migratory potential and the upregulation of eNOS and MMP9 gene expressions in HGFs. Chemical characterization revealed a 70 nm upshift in the photoluminescence emission spectra compared to the excitation wavelength. These novel photoactive BC-GQD hydrogel composites show great promise as effective agents for wound healing regeneration and infection management.

Characterization of the triphenylmethane dye (Patent Blue V)-modified Al/p-Si diode

The sol-gel spin coating method, an easily applicable, low-temperature, and inexpensive method, was used to grow Patent Blue V (PBV) organic thin films placed between metal and semiconductor. Atomic force microscope images were taken to reveal the morphological structure of the resulting organic film. FTIR, NMR, and UV-Vis measurements were taken to investigate the chemical features and optical structure of the PBV molecule. Using the traditional I-V, Cheung, and Norde methods of the produced Al/PBV/p-Si diode structure, ideality factor (n), barrier height (Φb), series resistance (Rs), and interfacial density of states (Nss) parameters were calculated. The differences between the results obtained with these methods arise from calculating the I-V characteristic of the methods from different regions. The ideality value of n for the produced diodes is much greater than one (n > > 1). Deviating the calculated n value from 1 indicates possible mechanisms, such as generation-recombination effect, organic PBV layer, and interfacial states. It was observed that the electronic parameters of the Al/p-Si conventional junction can be controlled using an organic PBV interlayer.Graphical abstract

MORPHOLOGICAL INSIGHTS OF CARBON NANOMATERIALS USING ATOMIC FORCE MICROSCOPY AND THEIR APPLICATIONS

This paper reviews the application of atomic force microscopy (AFM) in analyzing the nanoscale morphological properties of key carbon nanomaterials: carbon nanotubes (CNTs), graphene, and fullerene. AFM imaging techniques, operating at sub-nanometer resolutions of approximately 0.5 nm, are utilized to evaluate surface topography, roughness, and dimensional attributes. CNTs exhibit diameters ranging from 1[Formula: see text]nm to 10[Formula: see text]nm, with surface roughness correlating to their mechanical strength, reported to exceed 50[Formula: see text]GPa. For graphene, AFM measurements confirm a monolayer thickness of ∼0.34[Formula: see text]nm, while defects such as wrinkles and grain boundaries are identified, which significantly influence its exceptional thermal conductivity of up to 5000 W/mK. Fullerene structures, characterized by their spherical morphology and uniform diameters averaging 0.7[Formula: see text]nm, demonstrate superior dispersion in composite matrices. The review further explores the synergistic effects and trade-offs in utilizing these nanomaterials as fillers in composite systems. For instance, graphene improves electrical conductivity by over 200% in polymer composites, while CNTs contribute significantly to mechanical reinforcement, and fullerene enhances chemical stability and compatibility in biomedical applications. Through comparative analysis, the paper identifies pathways to optimize filler performance through tailored dispersion and functionalization. These insights serve as a foundation for future innovations in nanomaterial-enhanced composites across industries.

Chaperone-Mediated Heterotypic Phase Separation Prevents the Amyloid Formation of the Pathological Y145Stop Prion Protein Variant.

Biomolecular condensates formed via phase separation of proteins and nucleic acids are crucial for the spatiotemporal regulation of a diverse array of essential cellular functions and the maintenance of cellular homeostasis. However, aberrant liquid-to-solid phase transitions of such condensates are associated with several fatal human diseases. Such dynamic membraneless compartments can contain a range of molecular chaperones that can regulate the phase behavior of proteins involved in the formation of these biological condensates. Here, we show that a heat shock protein 40 (Hsp40), Ydj1, exhibits a holdase activity by potentiating the phase separation of a disease-associated stop codon mutant of the prion protein (Y145Stop) either by recruitment into Y145Stop condensates or via Y145Stop-Ydj1 two-component heterotypic phase separation that arrests the conformational conversion of Y145Stop into amyloid fibrils. Utilizing site-directed mutagenesis, multicolor fluorescence imaging, single-droplet steady-state and picosecond time-resolved fluorescence anisotropy, fluorescence recovery after photobleaching, and fluorescence correlation spectroscopy, we delineate the complex network of interactions that govern the heterotypic phase separation of Y145Stop and Ydj1. We also show that the properties of such heterotypic condensates can further be tuned by RNA that promotes the formation of multicomponent multiphasic protein-RNA condensates. Our vibrational Raman spectroscopy results in conjunction with atomic force microscopy imaging reveal that Ydj1 effectively redirects the self-assembly of Y145Stop towards a dynamically-arrested non-amyloidogenic pathway, preventing the formation of typical amyloid fibrils. Our findings underscore the importance of chaperone-mediated heterotypic phase separation in regulating aberrant phase transitions and amyloid formation associated with a wide range of deadly neurodegenerative diseases.

Controlled ligation and elongation of uniformly truncated amyloid nanofibrils.

This study investigates the production and inter-fibril interactions of uniformly truncated amyloid nanofibrils. By varying extrusion cycles (0, 50, and 100) and using carbonate filters with 100 nm and 200 nm pore sizes, precise fibril length control was achieved. Atomic force microscopy (AFM) confirmed that the mean length of the truncated fibrils corresponded to the respective pore size as extrusion cycles increased. AFM imaging combined with bicinchoninic acid assay analysis elucidated the mechanism underlying fibril truncation during extrusion. Subsequent incubation at 60 °C revealed that 200 nm-long fibrils assembled into denser structures than 100 nm-long fibrils, likely due to strain energy introduced during truncation, which appears to facilitate twisting during ligation and elongation between truncated fibrils. These findings advance understanding of the end-to-end elongation mechanisms of amyloid nanofibrils, shedding light on their structural dynamics and polymorphic properties.

Impurity-induced step pinning and recovery in MOVPE-grown (100) β-Ga2O3 film

This study focuses on the impact of high-doping impurities (>1018 cm−3) on the morphology of homoepitaxially grown (100) 4° off β-Ga2O3 film, as well as incorporating insights from the Cabrera–Vermilyea model (C–V model). Using atomic force microscopy imaging, we reveal that under low-supersaturation conditions, dopant-induced impurities lead to irregular step formation and growth stalling, inducing the step-bunching formation consistent with C–V model predictions. Conversely, higher supersaturation conditions restore desired step-flow morphology, resembling low-impurity growth states. It is also shown that the step-bunching formed under lower supersaturation conditions and high-impurity concentration might induce unwanted structural defects and compensate the free carriers. These findings underscore the delicate interplay between dopant concentrations, growth morphology, and supersaturation in metalorganic vapor phase epitaxy-grown (100) β-Ga2O3 films, providing a comprehensive understanding of optimizing their electrical properties with respect to power electronics applications.

Nano-viscosimetry analysis of membrane disrupting peptide magainin2 interactions with model membranes.

The rapid spread of antibiotic-resistant strains of bacteria has created an urgent need for new alternative antibiotic agents. Membrane disrupting antimicrobial peptides (AMPs): short amino acid sequences with bactericidal and fungicidal activity that kill pathogens by permeabilizing their plasma membrane may offer a solution for this global health crisis. Magainin 2 is an AMP secreted by the African clawed frog (Xenopus laevis) that is described as a toroidal pore former membrane disrupting AMP. Magainin 2 is one of the most thoroughly studied AMPs, yet its mechanism of action is still largely hypothetical: visual evidence of the pore formation is lacking, and the molecular mechanism leading to pore formation is still debated. In the present study, quartz crystal microbalance (QCM) based viscoelastic fingerprinting analysis supported by dye leakage experiments and atomic force microscopy (AFM) imaging was used to glean deeper insights into the mechanism of action. The effect of membrane charge, acyl chain unsaturation and cholesterol concentration were also investigated. The results show lipid specific disruptive mechanism of magainin 2. QCM nano-viscometry measurements revealed the presence of distinct stages in the mechanism of magainin 2 action that, with dye leakage data, confirm the existence of an initial transient pore stage that may result in peptide flip-flop between the outer and inner membrane leaflets. There is evidence of a further mechanistic stage at high peptide concentrations that is consistent with membrane collapse into a peptide-lipid mixed phase that is distinct from the transient pore formation. The results confirm some of the earliest hypotheses about magainin 2 action, while also highlighting the membrane modulating effect of this peptide.

A lifting-wavelet-based iterative thresholding correction for atomic force microscopy images with vertical distortion

To eliminate distortion caused by vertical drift and illusory slopes in atomic force microscopy (AFM) imaging, a lifting-wavelet-based iterative thresholding correction method is proposed in this paper. This method achieves high-quality AFM imaging via line-by-line corrections for each distorted profile along the fast axis. The key to this line-by-line correction is to accurately simulate the profile distortion of each scanning row. Therefore, a data preprocessing approach is first developed to roughly filter out most of the height data that impairs the accuracy of distortion modeling. This process is implemented through an internal double-screening mechanism. A line-fitting method is adopted to preliminarily screen out the obvious specimens. Lifting wavelet analysis is then carried out to identify the base parts that are mistakenly filtered out as specimens so as to preserve most of the base profiles and provide a good basis for further distortion modeling. Next, an iterative thresholding algorithm is developed to precisely simulate the profile distortion. By utilizing the roughly screened base profile, the optimal threshold, which is used to screen out the pure bases suitable for distortion modeling, is determined through iteration with a specified error rule. On this basis, the profile distortion is accurately modeled through line fitting on the finely screened base data, and the correction is implemented by subtracting the modeling result from the distorted profile. Finally, the effectiveness of the proposed method is verified through experiments and applications.

Deep learning-based denoising for unbiased analysis of morphology and stiffness in amyloid fibrils.

Understanding the morphology of amyloid fibrils is crucial for comprehending the aggregation and degradation mechanisms of abnormal proteins implicated in various diseases, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and various forms of amyloidosis. Atomic force microscopy (AFM) stands as the most representative method for studying amyloid fibril morphology. However, obstacles in AFM images, including noise, salt, and amorphous aggregates, often impede accurate sample quantification. In this study, we developed denoising software employing a U-Net deep learning architecture to address this issue. The software efficiently eliminated various impediments that interfere with fibril analysis in noisy AFM images, thereby facilitating precise quantification of amyloid fibrils. We also developed automated fibril analysis technologies using the denoised AFM images, leading to quicker, more precise, and more objective assessments of fibril morphology. Furthermore, we presented a method for fibril stiffness extraction from a modulus image through mask creation based on a denoised height image. Our approach secures time efficiency and precision in analyzing amyloid morphology, and we believe it will significantly advance the currently stagnant research on amyloid-related diseases.

Structural, Surface, and Optical Properties of Nitrogen-Doped Al:ZnO (NAZO) Thin Films Produced by a Thermionic Vacuum Arc Deposition Technology

Nitrogen (N)-doped Al:ZnO (NAZO) thin films were deposited on glass and indium tin oxide (ITO) coated glass by a thermionic vacuum arc (TVA) technique. The structural, surface morphology, and optical properties of the produced thin films were characterized by X-ray diffractometry (XRD), atomic force microscopy (AFM), and ultraviolet-visible spectroscopy. The microstructure properties of the produced thin films on two substrates were compared, and metal oxide phases were observed in the XRD patterns and photoluminescence spectra. 2.75, 3.10, and 3.30 eV band gaps were detected. The transmittance values were approximately 90% and 60% for the film deposited onto uncoated and ITO-coated glass, respectively. According to field-emission scanning electron microscopy and atomic force microscopy images, the crystallite size is nanoscale, and its dimensions are approximately 60 and 20 nm for the film deposited onto uncoated and ITO-coated glass substrates, respectively. Atomic ratios of zinc/aluminum were 9.25/0.56, and 5.42/0.22 for uncoated and ITO-coated glass substrate, respectively. All samples were coated with the same coating process, and no post-annealing process was applied to the sample.

Comprehensive characterization of tobacco-induced changes in enamel surface topography.

Enamel translucency, essential for the aesthetic appeal of teeth, is primarily determined by its thickness, quality, and refractive index. Several factors, including age, genetics, diet, oral hygiene practices, fluoride exposure, and acidic challenges, can influence enamel translucency. Tobacco use, in particular, leads to significant alterations in enamel appearance by penetrating its micropores, causing yellowing and browning. Prolonged exposure to tobacco results in demineralization, increasing enamel porosity and reducing its translucency. Over time, this exposure leads to permanent discoloration and structural degradation, rendering teeth dull and opaque. To assess these changes, various methods such as visual examinations, digital photography, spectrophotometry, stylus profilometry, and atomic force microscopy (AFM) are utilized. This study analyzed human enamel samples, including one unstained sample (Grade 0) and three tobacco-stained samples (Grades 1-3) according to Modified Lobene Stain Index (MLSI), to investigate the impact of tobacco exposure on enamel structure. The samples were thoroughly cleaned and dried to ensure accurate results. High-resolution AFM imaging was employed to assess surface roughness, porosity, and microstructural changes induced by tobacco staining. A stylus profilometer was used to trace the surface topography, providing detailed measurements of surface irregularities. Additionally, a spectrophotometer was utilized to evaluate the optical properties of the enamel, focusing on changes in translucency and light absorption due to tobacco exposure. AFM analysis revealed a clear progression of enamel surface roughness from Grade 0 to Grade 3. The Sa and Sq values increased significantly with the severity of tobacco staining, indicating greater surface degradation. The stylus profilometer data corroborated these findings, with rising Ra values as the degree of staining intensified, highlighting the topographical alterations caused by tobacco exposure. Spectrophotometric analysis further demonstrated a decrease in enamel reflectance and an increase in light absorption from mild to severe staining, underscoring the detrimental optical effects of tobacco on enamel. The combined use of AFM, stylus profilometry, and spectrophotometry provided a comprehensive assessment of the impact of tobacco staining on enamel translucency and surface roughness. The findings show that as staining severity increases, enamel translucency diminishes, and surface roughness worsens. These alterations not only affect the aesthetic appearance of teeth but also have potential implications for enamel functionality and long-term oral health.