Subtle Structural Features Research Articles

Enhanced Green Fluorescent Protein Streaming Dielectrophoresis in Insulator-Based Microfluidic Devices.

There is tantalizing evidence that proteins can be accurately and selectively manipulated by higher order electric field effects within microfluidic devices. The accurate and precise manipulation of proteins in these platforms promises to disrupt and revolutionize many fields, most notably analytical biochemistry. Several lines of experimental evidence suggest much higher forces are generated compared to those calculated from traditional theories and those higher forces arise from subtle structural features of the proteins providing selectivity. New theories reflect some of the experimental evidence in the magnitude of the force predicted and inclusion of subtle structural features absent in traditional continuum theory. Unfortunately, the experimental evidence is largely exploratory in nature and lacks one or more important elements that prevents a clear interpretation and comparison to not only the other existing data, but also quantitative comparison to the evolving theoretical descriptions. Here, a clear and interpretable experimental system is presented that quantitatively determines the dielectrophoretic susceptibility of unlabeled, unaggregated native-structure protein molecules that are exposed to modest electric fields (105-106V/m) for short periods of time (∼5ms) without significant increases in local concentration. The platform uses sub-nanogram quantities of protein, the probed volume upon determination is a few picoliters, and the total analysis time is 10 s.

Correcting Edge Defects in Self-Assembled Monolayers through Thermal Annealing.

Self-assembled monolayers (SAMs) are emerging as platform technology for a myriad of applications, yet they still possess varied spatial stability and predictability issues as their properties are heavily dependent on subtle structural features. Reducing entropy within such a system serves as one of many potential solutions to increase order and therefore coherence/precision in measured properties. Here we explore controlled thermal annealing to improve edge disorders in SAMs and significantly reduce data variance. Using both odd- and even-numbered n-alkanethiol SAMs on Au, we observe statistically significant difference in the contact angles between edge and center. Thermal annealing at 40°C significantly narrows differences between edges and centre of the SAM, albeit with significant reduction in the parity dependent odd-even effect. This study provides a pathway to improve SAMs consistency through minimal external perturbation as reflected by the minimization of odd-even effect as SAMs become increasingly ordered.

Steckman Ridge: A naturally fractured underground gas storage field

This paper presents a field development case study of a gas storage field in Pennsylvania within a fractured reservoir. Integration of multiple data sets was required for the project's success. During the study, the interpretation of 3D isofrequency seismic volumes, generated through spectral decomposition, was shown to be the key step in this data integration. The interpretation of these isofrequency volumes successfully identified previously unresolved subtle structural features, which controlled the natural fracture system. The existence of these subtle structural features was subsequently confirmed with eight horizontal gas storage wells. Accurate characterization of a fracture trend requires the integration of seismic data, available well data, surface geology, drilling, and production data. This study was performed to develop the Oriskany reservoir in the Steckman Ridge underground gas storage field located in Bedford County, Pennsylvania. This field had undergone rapid depletion during its primary production phase. During the early portion of the study, the reservoir was determined to be a type 1 fractured reservoir with little to no gas storage available in the sandstone matrix. Multiple data types were acquired and integrated to detect and characterize the structural features that compose the reservoir. Isofrequency volumes, developed through spectral decomposition of 3D seismic data over the field, helped identify and map subtle shear faults that proved to be controlling the location and orientation of the dominant fracture trend in the field. Horizontal boreholes, needed to convert the field from gas production to gas storage, were planned and drilled based on this seismic interpretation. The existence of these shear faults, their location, and their orientation were confirmed by image logs acquired along the length of six horizontal gas storage boreholes. Additionally, flow tests performed to determine gas deliverability supported this interpretation.

Data-driven topology optimization using a multitask conditional variational autoencoder with persistent homology

Topology optimization is crucial for the mechanical design of vehicles and aircraft, allowing changes in the shape of structures and the placement of features. Recent advances have integrated deep generative models, particularly convolutional neural networks, to streamline this process.to streamline this process. However, these models struggle to preserve subtle structural features. To overcome these limitations, this study introduced a generative model adept at identifying the topological features inherent in real shapes, such as connectivity and holes, to enhance the effectiveness of topology optimization. A conditional variational autoencoder (CVAE) was employed to predict both the shape and compliance simultaneously. This model, CVAE with persistent homology, generates optimal material distributions by considering topological properties. The learning process introduced a term that minimizes the difference in topological features between true and reconstructed shapes. The proposed model can generate optimal material distributions by considering topological properties, eliminating the need for iterative calculations. This approach was validated using two numerical examples. The accuracy of the generated material distributions was compared with conventional methods using the mean-squared error. An average improvement in accuracy of approximately 36.85% was observed across the two results. This confirms that shapes considering compliance and connectivity can be accurately predicted.

Influence of Composition and Structure on the Optoelectronic Properties of Photocatalytic Bi4NbO8Cl-Bi2GdO4Cl Intergrowths.

Mixed metal oxyhalides are an exciting class of photocatalysts, capable of the sustainable generation of fuels and remediation of pollutants with solar energy. Bismuth oxyhalides of the types Bi4MO8X (M = Nb and Ta; X = Cl and Br) and Bi2AO4X (A = most lanthanides; X = Cl, Br, and I) have an electronic structure that imparts photostability, as their valence band maxima (VBM) are composed of O 2p orbitals rather than X np orbitals that typify many other bismuth oxyhalides. Here, flux-based synthesis of intergrowth Bi4NbO8Cl-Bi2GdO4Cl is reported, testing the hypothesis that both intergrowth stoichiometry and M identity serve as levers toward tunable optoelectronic properties. X-ray scattering and atomically resolved electron microscopy verify intergrowth formation. Facile manipulation of the Bi4NbO8Cl-to-Bi2GdO4Cl ratio is achieved with the specific ratio influencing both the crystal and electronic structures of the intergrowths. This compositional flexibility and crystal structure engineering can be leveraged for photocatalytic applications, with comparisons to the previously reported Bi4TaO8Cl-Bi2GdO4Cl intergrowth revealing how subtle structural and compositional features can impact photocatalytic materials.

ОСОБЕННОСТИ КЛИНИЧЕСКИХ ПРОЯВЛЕНИЙ ПРИ МАЛЬФОРМАЦИИ КИАРИ 0, 1 И «ПОГРАНИЧНОГО» ТИПОВ

Introduction. Introduction of advanced neuroimaging methods has made it possible to identify subtle structural features of the posterior cranial fossa and craniovertebral junction, as well as the dislocation of cerebellar tonsils into the foramen magnum, which have clinically overt and subclinical forms. Aim: To study the clinical manifestation features of Chiari type 0, 1, and “borderline” malformations. Materials and Methods. For literature analysis, the sources were used from international databases, such as Web of Science, Scopus, and PubMed, and the Russian library system, eLibrary. Results and Discussion. The most common pathology of the posterior cranial fossa is Chiari type 1 malformation associated with a mesodermal defect and with discrepancies between the sizes of the posterior cranial fossa and the neural structures that fill it. To assess the Chiari malformation grade, it is advisable to specify the dislocation grades of cerebellar tonsils. There is a common classification of cerebellar tonsil dislocations, in which the dislocation grade 1 of cerebellar tonsils is characterized by the descent of cerebellar tonsils below the foramen magnum level; grade 2 is inherent in dislocation of the cerebellar tonsils down to the C2 vertebra level in combination with displacing the pons and medulla oblongata below the Twining line. Grade 3 dislocation of the cerebellar tonsils is where the cerebellum tonsil displacement is combined with intracranial hypertension. In case of the degree 4 dislocation of the cerebellar tonsils, cerebellar hypoplasia is observed, accompanied by a displacement of the medulla oblongata. The occurrence of syringomyelia in Chiari type 0 malformation is associated with liquor dynamic disorders in the craniovertebral junction region; the similar liquor circulation disorders are detected in Chiari type 1 malformation. Chiari type 1 and “borderline”- type malformations manifest as persistent cranialgia, pain in the cervical spine, otoneurologic and visual disorders, respiratory, psychological, and cognitive disorders, damage to the cerebellar and stem structures of the brain, damage to the spinal cord, and other, more rare signs of damage to the central nervous system. Conclusions. Thus, it is necessary to further study the features of developing clinical symptoms in Chiari type 1, 0, and “borderline” malformations to assess the changes in the course of the disease and select an adequate treatment strategy.

Spectroscopic Validation of Crystallographic Structures of a Protein Active Site by Chiroptical Spectroscopy.

Out-of-plane distortions of a cofactor molecule in a protein active site are functionally important, and in photoreceptors, it has been proposed that they are crucial for spectral tuning and energy storage in photocycle intermediates. However, these subtle structural features are often beyond the grasp of structural biology. This issue is strikingly exemplified by photoactive yellow protein: its 14 independently determined crystal structures exhibit considerable differences in the dihedral angles defining the chromophore geometry, even though most of these are at excellent resolution. Here we developed a strategy to verify cofactor distortions in crystal structures by using quantum chemical calculations and chiroptical spectroscopy, particularly Raman optical activity and electronic circular dichroism spectroscopies. Based on this approach, we identify seven crystal structures with the chromophore geometries inconsistent with the experimentally observed data. The strategy implemented here promises to be widely applicable to uncovering cofactor distortions at active sites and to studies of reaction intermediates.

QSAR modeling approaches to identify a novel ACE2 inhibitor that selectively bind with the C and N terminals of the ectodomain

Due to the high rates of drug development failure and the massive expenses associated with drug discovery, repurposing existing drugs has become more popular. As a result, we have used QSAR modelling on a large and varied dataset of 657 compounds in an effort to discover both explicit and subtle structural features requisite for ACE2 inhibitory activity, with the goal of identifying novel hit molecules. The QSAR modelling yielded a statistically robust QSAR model with high predictivity (R2 tr=0.84, R2 ex=0.79), previously undisclosed features, and novel mechanistic interpretations. The developed QSAR model predicted the ACE2 inhibitory activity (PIC50) of 1615 ZINC FDA compounds. This led to the detection of a PIC50 of 8.604 M for the hit molecule (ZINC000027990463). The hit molecule’s docking score is −9.67 kcal/mol (RMSD 1.4). The hit molecule revealed 25 interactions with the residue ASP40, which defines the N and C termini of the ectodomain of ACE2. The HIT molecule conducted more than thirty contacts with water molecules and exhibited polar interaction with the ARG522 residue coupled with the second chloride ion, which is 10.4 nm away from the zinc ion. Both molecular docking and QSAR produced comparable findings. Moreover, MD simulation and MMGBSA studies verified docking analysis. The MD simulation showed that the hit molecule-ACE2 receptor complex is stable for 400 ns, suggesting that repurposed hit molecule 3 is a viable ACE2 inhibitor.

Automatic 3D image based finite element modelling for metallic foams and accuracy verification of digital volume correlation

3D image-based finite element (FE) modelling provides the feasibility to explore how the subtle structural features inside metallic foams affect their complex deformation and mechanical responses. But the modelling currently includes frequent manual modifications, which makes it a time and labor consuming task. The quality of generated model depends heavily on experienced creator. This paper demonstrates an automatic procedure to extract structure information from 3D images and generate reliable geometric models for meshing. With self-adaptive algorithms that fit local features of grayscale distribution and internal structure, high-fidelity FE models can be established efficiently without interference from subjective judgments. The generated FE models well reproduce the stress-strain relation and inhomogeneous deformation of aluminium foams, compared with experimental results. Using the simulation with a high-fidelity FE model as “ground truth”, the accuracy of digital volume correlation (DVC) in the deformation measurement of complex cellular materials is for the first time evaluated quantitatively and precisely, based on the definition of an equivalent displacement vector bridging the results obtained by FE simulation and by DVC.

‘Pincer-tweezer’ tetraimidazolium salts as hosts for halides

In this work we describe the preparation of two tetracationic molecular tweezers that were used as hosts for the recognition of chloride, bromide and iodide. These two hosts contain a rigid bis-alkynyl spacer that connects two arms built with two pincer bis-imidazolium units. The nature of the spacer confers distinct structural features to these two molecular ‘pincer-tweezers’. The tweezer with the anthracenyl linker has a quasi-parallel disposition of the two arms of the tweezer, while in the carbazolyl-linked tweezer the two arms are significantly more separated. The study of the binding affinities of these two hosts with the three target halides showed substantial differences depending on the tetra-imidazolium tweezer used. In particular, the carbazolyl-based tweezer follows a 1:2 host:guest binding model, while the binding of the anthracenyl-linked tweezer is best explained using a 1:1 model. The different behavior is ascribed to the subtle different structural features of the two tetra-azolium receptors. The comparison of the affinities of the two tetracationic hosts with the related bis-imidazolium mono-pincer host indicates significantly enhanced association constants shown by the pincer-tweezer hosts, which are ascribed to a combination of the larger electrostatic attraction provided by the use of the tetracations together with the converging orientation of the two pincer bis-imidazoliums in the structure of the tweezers. These new tweezer-shaped tetra-imidazolium receptors are significantly different to other traditional tetrazoliums used as hosts for anions, which are mostly based on cyclic and more flexible structures. The pincer-tweezer hosts are acyclic and nevertheless more rigid than most of the poly-azolium-based receptors used until now.

Detailed Structural Features of the Perovskite-Related Halide RbPbI3 for Solar Cell Applications.

All-inorganic lead halide perovskites like CsPbBr3, CsPbI3, or RbPbI3 are good replacements for the classical hybrid organic–inorganic perovskites like CH3NH3PbI3, susceptible to fast degradation in the presence of humid air. They also exhibit outstanding light absorption properties suitable for solar energy applications. Here, we describe the synthesis of RbPbI3 by mechanochemical procedures with green credentials, avoiding toxic or expensive organic solvents; this specimen exhibits excellent crystallinity. We report neutron powder diffraction data, essential to revisit some subtle structural features around room temperature (200–400 K). In all these regimes, the orthorhombic Pnma crystal structure is characterized by the presence along the b direction of the crystal of double rows of edge-sharing PbI6 octahedra. The lone electron pairs of Pb2+ ions have a strong stereochemical effect on the PbI6 octahedral distortion. The relative covalency of Rb–I versus Pb–I bonds shows that the Pb–I-related motions are more rigid than Rb–I-related vibrations, as seen in the Debye temperatures from the evolution of the anisotropic displacements. The optical gap, measured by diffuse reflectance UV–vis spectroscopy, is ∼2.51 eV and agrees well with abinitio calculations. The thermoelectric Seebeck coefficient is 3 orders of magnitude larger than that of other halide perovskites, with a value of ∼117,000 μV·K–1 at 460 K.

Mechanistic insights into the C55-P targeting lipopeptide antibiotics revealed by structure-activity studies and high-resolution crystal structures.

The continued rise of antibiotic resistance is a global concern that threatens to undermine many aspects of modern medical practice. Key to addressing this threat is the discovery and development of new antibiotics that operate by unexploited modes of action. The so-called calcium-dependent lipopeptide antibiotics (CDAs) are an important emerging class of natural products that provides a source of new antibiotic agents rich in structural and mechanistic diversity. Notable in this regard is the subset of CDAs comprising the laspartomycins and amphomycins/friulimicins that specifically target the bacterial cell wall precursor undecaprenyl phosphate (C55-P). In this study we describe the design and synthesis of new C55-P-targeting CDAs with structural features drawn from both the laspartomycin and amphomycin/friulimicin classes. Assessment of these lipopeptides revealed previously unknown and surprisingly subtle structural features that are required for antibacterial activity. High-resolution crystal structures further indicate that the amphomycin/friulimicin-like lipopeptides adopt a unique crystal packing that governs their interaction with C55-P and provides an explanation for their antibacterial effect. In addition, live-cell microscopy studies provide further insights into the biological activity of the C55-P targeting CDAs highlighting their unique mechanism of action relative to the clinically used CDA daptomycin.

Relative Quantitation of Unsaturated Phosphatidylcholines Using 193 nm Ultraviolet Photodissociation Parallel Reaction Monitoring Mass Spectrometry.

Structural characterization of glycerophospholipids beyond the fatty acid level has become a major endeavor in lipidomics, presenting an opportunity to advance the understanding of the intricate relationship between lipid metabolism and disease state. Distinguishing subtle lipid structural features, however, remains a major challenge for high-throughput workflows that implement traditional tandem mass spectrometry (MS/MS) techniques, stunting the molecular depth of quantitative strategies. Here, reversed phase liquid chromatography is coupled to parallel reaction mass spectrometry utilizing the double bond localization capabilities of ultraviolet photodissociation (UVPD) mass spectrometry to produce double bond isomer specific responses that are leveraged for relative quantitation. The strategy provides lipidomic characterization at the double bond level for phosphatidylcholine phospholipids from biological extracts. In addition to quantifying monounsaturated lipids, quantitation of phospholipids incorporating isomeric polyunsaturated fatty acids is also achieved. Using this technique, phosphatidylcholine isomer ratios are compared across human normal and tumor breast tissue to reveal significant structural alterations related to disease state.

QSAR analysis of sodium glucose co–transporter 2 (SGLT2) inhibitors for anti-hyperglycaemic lead development

ABSTRACT QSAR (Quantitative Structure Activity Relationship) modelling was performed on a dataset of 90 sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors. The quantitative and explicative evaluations revealed some of the subtle and distinguished structural features that are responsible for the inhibitory potency of these compounds against SGLT2, such as less possible number of ring carbons at 8 Å from the lipophilic atoms in the molecule (fringClipo8A) and more possible value for the sum of the partial charges of the lipophilic atoms present within seven bonds from the donor atoms (lipo_don_7Bc). Multivariate GA–MLR (genetic algorithm–multi linear regression) and thorough validation methodology out-turned a statistically robust QSAR model with a very high predictability shown from various statistical parameters. A QSAR model with r 2 = 0.83, F = 51.54, Q 2 LOO = 0.79, Q 2 LMO = 0.79, CCC cv = 0.88, Q 2Fn = 0.76–0.81, r 2 ext = 0.77, CCC ext = 0.85, and with RMSEtr < RMSEcv was proposed. This QSAR model will assist synthetic chemists in the development of the SGLT2 inhibitors as the antidiabetic leads.

Machine-learning integrated glassy defect from an intricate configurational-thermodynamic-dynamic space

Optimizing materials' properties and functions by controlling defects in the crystalline phase has been a cornerstone of materials science and condensed matter physics. However, this paradigm has yet to be established in the broadly defined amorphous materials, which implies the identification of very subtle structural features in an otherwise uniformly disordered medium. Here we propose and define a new integrated glassy defect (IGD), based on machine learning strategy informed by atomistic physics, and also by an extremely wide configurational, thermodynamic, and dynamic variables space of the disordered state. The IGD simultaneously includes positional topology and vibrational features, as well as the local morphology of the potential energy landscape. This unprecedented combination gives rise to a much more comprehensive and more effective definition of the ``glassy defect,'' much beyond the conventional, purely structural input. IGD can be used not only as an efficient predictor of athermal plasticity but is also transferable to detect both short-time vibrational anomalies (the boson peak), and long-time relaxation and diffusion dynamics in glasses. The integrated strategy is instrumental to build the long-sought structure-property relationship in complex media.

Enhancing detection and characterization of lipids using charge manipulation in electrospray ionization-tandem mass spectrometry

Heightened awareness regarding the implication of disturbances in lipid metabolism with respect to prevalent human-related pathologies demands analytical techniques that provide unambiguous structural characterization and accurate quantitation of lipids in complex biological samples. The diversity in molecular structures of lipids along with their wide range of concentrations in biological matrices present formidable analytical challenges. Modern mass spectrometry (MS) offers an unprecedented level of analytical power in lipid analysis, as many advancements in the field of lipidomics have been facilitated through novel applications of and developments in electrospray ionization tandem mass spectrometry (ESI-MS/MS). ESI allows for the formation of intact lipid ions with little to no fragmentation and has become widely used in contemporary lipidomics experiments due to its sensitivity, reproducibility, and compatibility with condensed-phase modes of separation, such as liquid chromatography (LC). Owing to variations in lipid functional groups, ESI enables partial chemical separation of the lipidome, yet the preferred ion-type is not always formed, impacting lipid detection, characterization, and quantitation. Moreover, conventional ESI-MS/MS approaches often fail to expose diverse subtle structural features like the sites of unsaturation in fatty acyl constituents or acyl chain regiochemistry along the glycerol backbone, representing a significant challenge for ESI-MS/MS. To overcome these shortcomings, various charge manipulation strategies, including charge-switching, have been developed to transform ion-type and charge state, with aims of increasing sensitivity and selectivity of ESI-MS/MS approaches. Importantly, charge manipulation approaches afford enhanced ionization efficiency, improved mixture analysis performance, and access to informative fragmentation channels. Herein, we present a critical review of the current suite of solution-based and gas-phase strategies for the manipulation of lipid ion charge and type relevant to ESI-MS/MS.

Determination of sediments thickness in part of Lower Benue Trough, Nigeria, from the residualization of aeromagnetic data: Implication for diversification of the Nigerian economy

Aeromagnetic data were used in the study to determine the sediment thickness in the Lower Benue Trough. To achieve the objectives of the study, geophysical techniques were employed to analyze four aeromagnetic maps on a scale of 1:100,000, covering parts of the Lower Benue Trough. These include map merging, polynomial fitting, directional derivatives and forward modeling. Nine (9) profiles were modeled to determine sediment thickness, presence of possible intrusives and the subtle structural features and their trend within the study area. Results from this study revealed the existence of many intrusives which were majorly granite and basalt rocks which suggests complex tectonic events which accompanied the evolution of the Benue Trough. Lineament orientation revealed is majorly NE-SW direction and other directions were NW-SE, E-W and N-S. A sedimentary thickness ranging from 7 to 10 km were suggested by a 3D forward modeling, and this estimated depth did not coincide with an average of 5 km suggested by earlier researchers. Huge variations within the basement complex are however induced by the presence of horst structures as well as graben and this is profound within the depocenters where sedimentary pile is thicker. Magnetic sources within the sediment in Abakiliki, Udi and Nkalagu areas have potentials for hydrocarbon accumulation due to the thickness of the sediments in these parts of the study area. However, Bansara area reveals the presence of lots of intrusives, indicating high geothermal regimes that may not be favourable for hydrocarbon accumulation but have high potentials for solid mineral resources. Therefore, the Bansara area is recommended for organised and formal solid mineral exploration, which can apparently diversified the economy of Nigeria.

Rational design of a near-infrared fluorescence probe for highly selective sensing butyrylcholinesterase (BChE) and its bioimaging applications in living cell

In the current work, a near-infrared (NIR) fluorescent probe (CyClCP) was developed for fast (35 min), highly sensitive (LOD of 3.75 U/L) and selective response to BChE in vitro and in vivo. Upon the addition of BChE, CyClCP could be efficiently activated with remarkable NIR (λem = 708 nm) fluorescence enhancement and obvious absorbance red shift (581 nm–687 nm). Specifically, according to the subtle differences structural features and substrate preference between BChE and its sister enzyme AChE, CyClCP was constructed by introducing chlorine atom at the ortho-position of the phenolic hydroxyl in the previous reported probe (CyCP). Fortunately, CyClCP exhibited better selectivity towards BChE over AChE compared with CyCP. This molecular design strategy was further rationalized by docking molecular of fluorescence probes (CyClCP and CyCP) and enzymes (BChE and AChE). Finally, CyClCP was membrane permeable and successfully applied to image endogenous BChE level in HepG2 and LO2 cells. Therefore, CyClCP could serve as a promising tool for BChE-related physiological function studies in complex biological systems.

On the redistribution of charge in La0.7Sr0.3CrO3/La0.7Sr0.3MnO3 multilayer thin films

The atomic and electronic structures of La0.7Sr0.3MnO3 (LSMO)/La0.7Sr0.3CrO3 (LSCO) multilayer thin films are investigated using aberration corrected scanning transmission electron microscopy (STEM) imaging and spectroscopy. Atomic resolution high angle annular dark-field reveals that LSMO layers have an expanded out-of-plane lattice parameter compared to compressed LSCO layers, contrasting with x-ray diffraction measurements. The expansion is found to result from preferential oxygen vacancy formation in LSMO during STEM sample preparation as determined by electron energy-loss spectroscopy. The La/Sr atom column intensity is also found to oscillate by about 4% between the LSMO and LSCO layers, indicative of La/Sr concentration variation. Using energy-dispersive x-ray spectroscopy in combination with image simulations, we confirm the La/Sr inhomogeneity and elucidate the origin of charge redistribution within the multilayer. These results illuminate the sensitivity of the technique to subtle structural, chemical, and electronic features that can arise to compensate charge imbalances in complex oxide heterostructures.

LED array reflectance microscopy for scattering-based multi-contrast imaging.

LED array microscopy is an emerging platform for computational imaging with significant utility for biological imaging. Existing LED array systems often exploit transmission imaging geometries of standard brightfield microscopes that leave the rich backscattered field undetected. This backscattered signal contains high-resolution sample information with superb sensitivity to subtle structural features that make it ideal for biological sensing and detection. Here, we develop an LED array reflectance microscope capturing the sample's backscattered signal. In particular, we demonstrate multimodal brightfield, darkfield, and differential phase contrast imaging on fixed and living biological specimens including Caenorhabditis elegans (C. elegans), zebrafish embryos, and live cell cultures. Video-rate multimodal imaging at 20 Hz records real time features of freely moving C. elegans and the fast beating heart of zebrafish embryos. Our new reflectance mode is a valuable addition to the LED array microscopic toolbox.