Research Progress and Clinical Application of All-Ceramic Micro-Veneer.

Anterior teeth problems affect the patient's daily eating, communication, social activities, self-confidence, and mental health. The trend in dentistry is to address anterior tooth problems with minimally invasive and aesthetic treatments. With the development of adhesive materials and ceramics, micro-veneers have been proposed as an alternative treatment for enhancing the aesthetic appearance and avoiding unnecessary tooth reduction. A micro-veneer is a veneer that can be cemented to the surface without or with minimal tooth preparation. These benefits include no need for anesthesia, postoperative insensitivity, good adhesion to enamel, reversibility of treatment, and higher patient acceptance. However, the micro-veneer repair is suitable only for specific cases and must be strictly controlled regarding indication. Treatment planning is a crucial step to achieving functional and aesthetic rehabilitation, and following the clinical protocol is helpful for the longevity and success of micro-veneer restorations. However, more precise and predictable tooth preparation methods, such as minimally invasive microscopic tooth preparation and digitally guided veneer preparation, are recommended rather than the traditional free-hand method. Therefore, this paper clarifies micro-veneers and compares them with other restorations to gain a deeper and more comprehensive understanding. The authors also review indications, materials, cementation, and effect evaluation of micro-veneers to provide clinicians with valuable information. In conclusion, micro-veneers are minimally invasive treatments that provide good restoration results when used appropriately and are worthy of promotion for the aesthetic restoration of anterior teeth.

Label-free imaging and biomarker analysis of exosomes with plasmonic scattering microscopy.

Exosome analysis is a promising tool for clinical and biological research applications. However, detection and biomarker quantification of exosomes is technically challenging because they are small and highly heterogeneous. Here, we report an optical approach for imaging exosomes and quantifying their protein markers without labels using plasmonic scattering microscopy (PSM). PSM can provide improved spatial resolution and distortion-free image compared to conventional surface plasmon resonance (SPR) microscopy, with the signal-to-noise ratio similar to objective coupled surface plasmon resonance (SPR) microscopy, and millimeter-scale field of view as a prism-coupled SPR system, thus allowing exosome size distribution analysis with high throughput. In addition, PSM retains the high specificity and surface sensitivity of the SPR sensors and thus allows selection of exosomes from extracellular vesicles with antibody-modified sensor surfaces and in situ analyzing binding kinetics between antibody and the surface protein biomarkers on the captured exosomes. Finally, the PSM can be easily constructed on a popular prism-coupled SPR system with commercially available components. Thus, it may provide an economical and powerful tool for clinical exosome analysis and exploration of fundamental issues such as exosome biomarker binding properties.

Single Protein Detection and Imaging with Evanescent Scattering Microscopy.

Single-molecule measurements provide statistical distributions of molecular properties, in addition to the ensemble averages. Evanescent detection approaches have been widely used for single-molecule detection because the evanescent field can significantly enhance the light-analyte interaction and reduce the background noise. However, current evanescent single-molecule detection systems mostly require specially designed sensing components. Here, we show that single proteins can be imaged on a plain cover glass surface by detecting the evanescent waves scattered by the target molecules. This allows us to quantify the protein-antibody interactions at the single-molecule level. This protocol describes a label-free single-molecule imaging approach with conventional consumables and may pave the road for detecting single molecules with commercial optical microscopy.

Rapid Regulation of Local Temperature and Transient Receptor Potential Vanilloid 1 Ion Channels with Wide-Field Plasmonic Thermal Microscopy.

Plasmonic absorption of light can create significant local heat and has become a promising tool for rapid temperature regulation in diverse fields, from biomedical technology to optoelectronics. Current plasmonic heating usually relies on specially designed nanomaterials randomly distributed in the space and barely provides uniform temperature regulation in a wide field. Herein, we report a rapid temperature regulation strategy on a plain gold-coated glass slip using a plasmonic scattering microscopy, which can be referred to as wide-field plasmonic thermal microscopy (W-PTM). We calibrated the W-PTM by monitoring the phase transition of the temperature-sensitive polymer solutions, showing that it can provide a temperature regulation range of 33-80 °C. Moreover, the W-PTM provides imaging capability, thus allowing the statistical analysis of the phase-transitioned polymeric nanoparticles. Finally, we demonstrated that W-PTM can be used for noninvasive and local regulation of the transient receptor potential vanilloid 1 (TRPV1) ion channels in the living cells, which can be monitored by simultaneous fluorescence imaging of the calcium influx. With the nondestructive local temperature-regulating and concurrent fluorescence imaging capability, we anticipate that W-PTM can be a powerful tool to study cellular activities associated with cellular membrane temperature changes.

In Situ Analysis of Membrane-Protein Binding Kinetics and Cell-Surface Adhesion Using Plasmonic Scattering Microscopy.

Surface plasmon resonance microscopy (SPRM) is an excellent platform for in situ studying cell-substrate interactions. However, SPRM suffers from poor spatial resolution and small field of view. Herein, we demonstrate plasmonic scattering microscopy (PSM) by adding a dry objective on a popular prism-coupled surface plasmon resonance (SPR) system. PSM not only retains SPRM's high sensitivity and real-time analysis capability, but also provides ≈7 times higher spatial resolution and ≈70 times larger field of view than the typical SPRM, thus providing more details about membrane protein response to ligand binding on over 100 cells simultaneously. In addition, PSM allows quantifying the target movements in the axial direction with a high spatial resolution, thus allowing mapping adhesion spring constants for quantitatively describing the mechanical properties of the cell-substrate contacts. This work may offer a powerful and cost-effective strategy for upgrading current SPR products.

Rapid Detection of Urinary Tract Infection in 10 min by Tracking Multiple Phenotypic Features in a 30 s Large-Volume Scattering Video of Urine Microscopy.

Rapid point-of-care (POC) diagnosis of bacterial infection diseases provides clinical benefits of prompt initiation of antimicrobial therapy and reduction of the overuse/misuse of unnecessary antibiotics for nonbacterial infections. We present here a POC compatible method for rapid bacterial infection detection in 10 min. We use a large-volume solution scattering imaging (LVSi) system with low magnifications (1-2×) to visualize bacteria in clinical samples, thus eliminating the need for culture-based isolation and enrichment. We tracked multiple intrinsic phenotypic features of individual cells in a short video. By clustering these features with a simple machine learning algorithm, we can differentiate Escherichia coli from similar-sized polystyrene beads, distinguish bacteria with different shapes, and distinguish E. coli from urine particles. We applied the method to detect urinary tract infections in 104 patient urine samples with a 30 s LVSi video, and the results showed 92.3% accuracy compared with the clinical culture results. This technology provides opportunities for rapid bacterial infection diagnosis at POC settings.

Label-Free Imaging of Single Proteins and Binding Kinetics Using Total Internal Reflection-Based Evanescent Scattering Microscopy.

Single-molecule detection can push beyond ensemble averages and reveal the statistical distributions of molecular properties. Measuring the binding kinetics of single proteins also represents one of the critical and challenging tasks in protein analysis. Here, we report total internal reflection-based evanescent scattering microscopy with label-free single-protein detection capability. Total internal reflection is employed to excite the evanescent field to enhance light-analyte interaction and reduce environmental noise. As a result, the system provides wide-field imaging capability and allows excitation and observation using one objective. In addition, this system quantifies protein binding kinetics by simultaneously counting the binding of individual molecules and recording their binding sites with nanometer precision, providing a digital method to measure binding kinetics with high spatiotemporal resolution. This approach does not employ specially designed microspheres or nanomaterials and may pave a way for label-free single-protein analysis in conventional microscopy.

Evanescent scattering imaging of single protein binding kinetics and DNA conformation changes.

Evanescent illumination has been widely used to detect single biological macromolecules because it can notably enhance light-analyte interaction. However, the current evanescent single-molecule detection system usually requires specially designed microspheres or nanomaterials. Here we show that single protein detection and imaging can be realized on a plain glass surface by imaging the interference between the evanescent lights scattered by the single proteins and by the natural roughness of the cover glass. This allows us to quantify the sizes of single proteins, characterize the protein-antibody interactions at the single-molecule level, and analyze the heterogeneity of single protein binding behaviors. In addition, owing to the exponential distribution of evanescent field intensity, the evanescent imaging system can track the analyte axial movement with high resolution, which can be used to analyze the DNA conformation changes, providing one solution for detecting small molecules, such as microRNA. This work demonstrates a label-free single protein imaging method with ordinary consumables and may pave a road for detecting small biological molecules.

Multiband topological states in non-Hermitian photonic crystals.

Novel phenomena found in non-Hermitian systems and robust edge states have attracted much attention. When non-Hermitian parameters (gain and loss) are above a critical value, the non-Hermitian photonic crystal (PC) bandgaps close, leading to a mixture of the topological edge state (TES) and topological corner state (TCS) with the bulk state. Meanwhile, new bandgaps also open, in which new TES and TCS can appear. Thus, with appropriate non-Hermitian parameters, TES can emerge in both the original bandgaps and the newly opened bandgaps. The results described here will further enrich understanding of the topological properties of non-Hermitian systems.

Label-Free Imaging of Nanoscale Displacements and Free-Energy Profiles of Focal Adhesions with Plasmonic Scattering Microscopy.

Cell adhesion plays a critical role in cell communication, cell migration, cell proliferation, and integration of medical implants with tissues. Focal adhesions physically link the cell cytoskeleton to the extracellular matrix, but it remains challenging to image single focal adhesions directly. Here, we show that plasmonic scattering microscopy (PSM) can directly image the single focal adhesions in a label-free, real-time, and non-invasive manner with sub-micrometer spatial resolution. PSM is developed based on surface plasmon resonance (SPR) microscopy, and the evanescent illumination makes it immune to the interference of intracellular structures. Unlike the conventional SPR microscopy, PSM can provide a high signal-to-noise ratio and sub-micrometer spatial resolution for imaging the analytes with size down to a single-molecule level, thus allowing both the super-resolution lateral localization for measuring the nanoscale displacement and precise tracking of vertical distances between the analyte centroid and the sensor surface for analysis of free-energy profiles. PSM imaging of the RBL-2H3 cell with temporal resolution down to microseconds shows that the focal adhesions have random diffusion behaviors in addition to their directional movements during the antibody-mediated activation process. The free-energy mapping also shows a similar movement tendency, indicating that the cell may change its morphology upon varying the binding conditions of adhesive structures. PSM provides insights into the individual focal adhesion activities and can also serve as a promising tool for investigating the cell/surface interactions, such as cell capture and detection and tissue adhesive materials screening.

Rapid Antimicrobial Susceptibility Testing on Clinical Urine Samples by Video-Based Object Scattering Intensity Detection.

To combat the ongoing public health threat of antibiotic-resistant infections, a technology that can quickly identify infecting bacterial pathogens and concurrently perform antimicrobial susceptibility testing (AST) in point-of-care settings is needed. Here, we develop a technology for point-of-care AST with a low-magnification solution scattering imaging system and a real-time video-based object scattering intensity detection method. The low magnification (1-2×) optics provides sufficient volume for direct imaging of bacteria in urine samples, avoiding the time-consuming process of culture-based bacterial isolation and enrichment. Scattering intensity from moving bacteria and particles in the sample is obtained by subtracting both spatial and temporal background from a short video. The time profile of scattering intensity is correlated with the bacterial growth rate and bacterial response to antibiotic exposure. Compared to the image-based bacterial tracking and counting method we previously developed, this simple image processing algorithm accommodates a wider range of bacterial concentrations, simplifies sample preparation, and greatly reduces the computational cost of signal processing. Furthermore, development of this simplified processing algorithm eases implementation of multiplexed detection and allows real-time signal readout, which are essential for point-of-care AST applications. To establish the method, 130 clinical urine samples were tested, and the results demonstrated an accuracy of ∼92% within 60-90 min for UTI diagnosis. Rapid AST of 55 positive clinical samples revealed 98% categorical agreement with both the clinical culture results and the on-site parallel AST validation results. This technology provides opportunities for prompt infection diagnosis and accurate antibiotic prescriptions in point-of-care settings.

Oral Treponema denticola Infection Induces Aß1-40 and Aß1-42 Accumulation in the Hippocampus of C57BL/6 Mice.

Accumulation of amyloid-ß (Aß) in the brain is a central component of pathology in Alzheimer's disease. A growing volume of evidence demonstrates close associations between periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) and Treponema denticola (T. denticola) and AD. However, the effect and mechanisms of T. denticola on accumulation of Aß remain to be unclear. In this study, we demonstrated that T. denticola was able to enter the brain and act directly on nerve cells resulting in intra- and extracellular Aß1-40 and Aß1-42 accumulation in the hippocampus of C57BL/6 mice by selectively activating both ß-secretase and γ-secretase. Furthermore, both KMI1303, an inhibitor of ß-secretase, as well as DAPT, an inhibitor of γ- secretase, were found to be able to inhibit the effect of T. denticola on Aß accumulation in N2a neuronal cells. Overall, it is concluded that T. denticola increases the expression of Aß1-42 and Aß1-40 by its regulation on beta-site amyloid precursor protein cleaving enzyme-1 and presenilin 1.

Imaging Single Bacterial Cells with Electro-optical Impedance Microscopy.

Impedance measurements have been an important tool for biosensor applications, including protein detection, DNA quantification, and cell study. We present here an electro-optical impedance microscopy (EIM) based on the dependence of surface optical transmission on local surface charge density for single bacteria impedance imaging. We applied a potential modulation to bacteria placed on an indium tin oxide-coated slide and simultaneously recorded a sequence of transmitted microscopy images. By performing fast Fourier transform analysis on the image sequences, we obtained the DC component (signal at 0 Hz) for cell morphology imaging and the AC component (signal at the modulation frequency) for the mapping of cell impedance responses with subcellular resolution for the first time. Using this method, we have monitored the viability of Escherichia coli bacterial cells under treatment with two different classes of antibiotics with low-frequency potential modulation. The results showed that the impedance response is sensitive to the antibiotic that targets the bacterial cell membrane as the membrane capacitance dominated at low-frequency modulation. Heterogeneous responses to the antibiotic treatment were observed at a single bacteria level. In addition to the high spatial resolution, EIM is label-free and simple and can be potentially used for the continuous mapping of single bacteria impedance changes under different conditions.

Direct Antimicrobial Susceptibility Testing on Clinical Urine Samples by Optical Tracking of Single Cell Division Events.

With the increasing prevalence of antibiotic resistance, the need to develop antimicrobial susceptibility testing (AST) technologies is urgent. The current challenge has been to perform the antibiotic susceptibility testing in short time, directly with clinical samples, and with antibiotics over a broad dynamic range of clinically relevant concentrations. Here, a technology for point-of-care diagnosis of antimicrobial-resistant bacteria in urinary tract infections, by imaging the clinical urine samples directly with an innovative large volume solution scattering imaging (LVSi) system and analyzing the image sequences with a single-cell division tracking method is developed. The high sensitivity of single-cell division tracking associated with large volume imaging enables rapid antibiotic susceptibility testing directly on the clinical urine samples. The results demonstrate direct detection of bacterial infections in 60 clinical urine samples with a 60 min LVSi video, and digital AST of 30 positive clinical samples with 100% categorical agreement with both the clinical culture results and the on-site agar plating validation results. This technology provides opportunities for precise antibiotic prescription and proper treatment of the patient within a single clinic visit.

High-throughput extracellular pH monitoring and antibiotics screening by polymeric fluorescent sensor with LCST property.

Monitoring extracellular pH (pHe) is important for biology understanding, since pHe and its homeostasis are closely relevant to cellular metabolism. Hydrogel-based pHe sensors have attracted significant attention and showed wide application, while they are tedious with significant time-cost operation and reproducibility variations for high-throughput application. Herein, we synthesized two polymers for pHe monitoring which are soluble in water at room temperature with easy operations and high reproducibility among various micro-plate wells for high-throughput analysis. P1 (P(OEGMA-co-MEO2MA-co-pHS)) and P2 (P(OEGMA-co-pHS)) were synthesized via the Reversible Addition Fragmentation Chain Transfer (RAFT) copolymerization of oligo(ethylene glycol) methacrylate (OEGMA), 2-(2'-methoxyethoxy) ethyl methacrylate (MEO2MA) and the pH sensitive fluorescence moiety N-fluoresceinyl methacrylamide (pHS). P1 is soluble in water at room temperature (25 °C) while insoluble at the temperature above 33 °C, indicating its feature of lower critical solution temperature (LCST) at 33 °C. Further P1 showed higher pH sensitivity and photostability than P2 (without LCST property) when used at physiological temperature (37 °C). Thus, P1 was chosen to in-situ monitor the micro-environmental acidification of E. coli, Hela and Ramos cells during their growth, and the metabolism inhibiting activity of a representative antibiotic, ampicillin. Cell concentration-dependent cellular acidification and drug concentration-dependent inhibition of cellular acidification were observed, demonstrating that the LCST polymer (P1) is suitable for real-time cellular acidification monitoring as well as for high-throughput drug screening. This study firstly demonstrated the use of a LCST polymeric sensor for high-throughput screening of antibiotics and investigation of cell metabolism.

Electrospun nanofibers and spin coated films prepared from side-chain copolymers with chemically bounded platinum (II) porphyrin moieties for oxygen sensing and pressure sensitive paints.

Pressure sensitive paints (PSP) containing oxygen probes were primarily used to measure air pressure. In this perspective, a polymerizable methacrylate-derived tetraphenylporphinato platinum(II) (PtTPP-MA) monomer was copolymerized with acrylic/vinyl monomers to produce four different copolymers. Octafluoropentyl methacrylate (OCFPM) and pentafluorophenyl acrylate (PFPA) were used as fluorinated monomers. Methyl methacrylate (MMA) and styrene (S) were used as non-fluorinated monomers. The structures and physical properties of the polymers were confirmed by 1H NMR, 19F NMR, GPC, and DSC. Experimental conditions were optimized to get fine nanofibers. Pressure sensing electrospun membranes and spin coated films were fabricated. Nanofibers showed fast response and good sensitivity towards gaseous oxygen. The influence of types of substrate and polymer natures on response time, oxygen sensitivity, and pressure responses were deliberated. Among our synthesized copolymers, poly(PS-co-PFPA-co-OCFPM-co-PtTPPMA) (Polymer P3) showed fast response time and good pressure sensitivity both as spin coated films and nanofibers.