Search

Tuberculosis (TB) is among the greatest public health and safety concerns in the 21(st) century, Mycobacterium tuberculosis, which causes TB, infects alveolar macrophages and uses these cells as one of its primary sites of replication. The current TB treatment regimen, which consist of chemotherapy involving a combination of 3-4 antimicrobials for a duration of 6-12 months, is marked with significant side effects, toxicity, and poor compliance. Targeted drug delivery offers a strategy that could overcome many of the problems of current TB treatment by specifically targeting infected macrophages. Recent advances in nanotechnology and material science have opened an avenue to explore drug carriers that actively and passively target macrophages. This approach can increase the drug penetration into macrophages by using ligands on the nanocarrier that interact with specific receptors for macrophages. This review encompasses the recent development of drug carriers specifically targeting macrophages actively and passively. Future directions and challenges associated with development of effective TB treatment is also discussed.

FRET is ascribed to the spectral overlapping of upconversion luminescence and the absorption of AuNPs. This experiment enables early-stage coronavirus detection. The results show a sensitivity of 100 fM for the detection of COVID-19 DNA.

The nature of cell membrane fluidity permits glycans, which are attached to membrane proteins and lipids, to freely diffuse on cell surfaces. Through such two-dimensional motion, some weakly binding glycans can participate in lectin binding processes, eventually changing lectin binding behaviors. This chapter discusses a plasmonic nanocube sensor that allows users to detect lectin binding kinetics in a cell membrane mimicking environment. This assay only requires standard laboratory spectrometers, including microplate readers. We describe the basics of the technology in detail, including sensor fabrication, sensor calibration, data processing, a general protocol for detecting lectin-glycan interactions, and a troubleshooting guide.

We recently discovered that the nature of lectin multivalency and glycolipid diffusion on cell membranes could lead to the heteromultivalent binding (i.e., a single lectin simultaneously binding to different types of glycolipid ligands). This heteromultivalent binding may even govern the lectin-glycan recognition process. To investigate this, we developed a kinetic Monte Carlo simulation, which only considers the fundamental physics/chemistry principles, to model the process of lectin binding to glycans on cell surfaces. We found that the high-affinity glycan ligands could facilitate lectin binding to other low-affinity glycan ligands, even though these low-affinity ligands are barely detectable in microarrays with immobilized glycan ligands. Such heteromultivalent binding processes significantly change lectin binding behaviors. We hypothesize that living organisms probably utilize this mechanism to regulate the downstream lectin functions. Our finding not only offers a mechanism to describe the concept that lectins are pattern recognition molecules, but also suggests that the two overlooked parameters, surface diffusion of glycan ligand and lectin binding kinetics, can play important roles in glycobiology processes. In this paper, we identified the critical parameters that influence the heteromultivalent binding process. We also discussed how our discovery can impact the current lectin-glycan analysis.

Fighting zoonotic coronaviruses In the past 20 years, three betacoronaviruses thought to have originated in bats have caused devastating disease in humans. The global pandemic caused by the latest such virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highlights the need to protect against other strains that could present a threat to humans. Cohen et al. constructed nanoparticles displaying the protein domain that binds the host cell receptor (receptor-binding domain or RBD), either a homotypic SARS-CoV-2 particle or mosaic particles displaying RBDs from four or eight different betacoronaviruses. In mice, antibodies to the SARS-CoV-2 RBD were elicited just as well by mosaic particles as by homotypic nanoparticles. The mosaic nanoparticles elicited antibodies that, beyond recognizing the strains displayed, also recognized mismatched strains. Science, this issue p. 735, Immunizing with nanoparticles that display diverse coronavirus receptor binding domains elicits cross-reactive and neutralizing antibody responses., Protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and SARS-related emergent zoonotic coronaviruses is urgently needed. We made homotypic nanoparticles displaying the receptor binding domain (RBD) of SARS-CoV-2 or co-displaying SARS-CoV-2 RBD along with RBDs from animal betacoronaviruses that represent threats to humans (mosaic nanoparticles with four to eight distinct RBDs). Mice immunized with RBD nanoparticles, but not soluble antigen, elicited cross-reactive binding and neutralization responses. Mosaic RBD nanoparticles elicited antibodies with superior cross-reactive recognition of heterologous RBDs relative to sera from immunizations with homotypic SARS-CoV-2–RBD nanoparticles or COVID-19 convalescent human plasmas. Moreover, after priming, sera from mosaic RBD–immunized mice neutralized heterologous pseudotyped coronaviruses as well as or better than sera from homotypic SARS-CoV-2–RBD nanoparticle immunizations, demonstrating no loss of immunogenicity against particular RBDs resulting from co-display. A single immunization with mosaic RBD nanoparticles provides a potential strategy to simultaneously protect against SARS-CoV-2 and emerging zoonotic coronaviruses.

Matching of symmetry at interfaces is a fundamental obstacle in molecular assembly. Virus‐like particles (VLPs) are important vaccine platforms against pathogenic threats, including Covid‐19. However, symmetry mismatch can prohibit vaccine nanoassembly. We established an approach for coupling VLPs to diverse antigen symmetries. SpyCatcher003 enabled efficient VLP conjugation and extreme thermal resilience. Many people had pre‐existing antibodies to SpyTag:SpyCatcher but less to the 003 variants. We coupled the computer‐designed VLP not only to monomers (SARS‐CoV‐2) but also to cyclic dimers (Newcastle disease, Lyme disease), trimers (influenza hemagglutinins), and tetramers (influenza neuraminidases). Even an antigen with dihedral symmetry could be displayed. For the global challenge of influenza, SpyTag‐mediated display of trimer and tetramer antigens strongly induced neutralizing antibodies. SpyCatcher003 conjugation enables nanodisplay of diverse symmetries towards generation of potent vaccines., Nanoassembly can play a key role in generating effective vaccines for emerging (SARS‐CoV‐2) and established (influenza) pandemic threats. SpyTag‐mediated display was used to adapt the nanocage to the challenge of bacterial or viral antigens with diverse cyclic and dihedral symmetries. Establishing display of both trimeric and tetrameric antigens may lead to an influenza vaccine with broader protection.

The design of plasmonic nanostructures could have many exciting applications since it enhances or provides valuable control over efficient energy conversion. A three-dimensional (3D) space is a realistic hotspot matrix harvesting a wide conversion that has been shown in zero-dimensional nanoparticles, one-dimensional linear structures, or two-dimensional films. A novel 3D plasmonic nanostructure platform consisting of plasmonic metal nanoparticles in discoidal porous silicon particles is used in this study. Plasmonic gold nanoparticles are anchored inside the discoidal porous silicon (DPS) particles by in situ reduction synthesis. The novel plasmonic nanostructures can tailor the plasmon band and overcome the instability of photothermal materials. The “trapping well” for the anchored nanoparticles in 3D space can result in a huge change of plasmonic band of metal nanoparticles to the near-IR region in a novel 3D geometry. A multifunctional scaffold, Au–DPS particle, composed of doxorubicin conjugated to poly-(L-glutamic acid) (pDOX), was developed for combinatorial chemo-photothermal cancer therapy. The therapeutic efficacy was examined in treatment of the A549 cell line under near-IR laser irradiation. The highly efficient photothermal conversion can also be demonstrated in the laser desorption/ionization time-of-flight mass spectrometry detection analysis. The limit of detection was obviously improved in the detection of angiotensin II, P14R, and ACTH fragments 18-39 peptides. Overall, we envision that Au–DPS particles may be used in ultrasensitive theranostics in the future.

GM1 has generally been considered as the major receptor that binds to cholera toxin subunit B (CTB) due to its low dissociation constant. However, using a unique nanocube sensor technology, we have shown that CTB can also bind to other glycolipid receptors, fucosyl-GM1 and GD1b. Additionally, we have demonstrated that GM2 can contribute to CTB binding if present in a glycolipid mixture with a strongly binding receptor (GM1/fucosyl-GM1/GD1b). This hetero-multivalent binding result was unintuitive because the interaction between CTB and pure GM2 is negligible. We hypothesized that the reduced dimensionality of CTB-GM2 binding events is a major cause of the observed CTB binding enhancement. Once CTB has attached to a strong receptor, subsequent binding events are confined to a 2D membrane surface. Therefore, even a weak GM2 receptor could now participate in second or higher binding events because its surface reaction rate can be up to 104 times higher than the bulk reaction rate. To test this hypothesis, we altered the surface reaction rate by modulating the fluidity and heterogeneity of the model membrane. Decreasing membrane fluidity reduced the binding cooperativity between GM2 and a strong receptor. Our findings indicated a new protein-receptor binding assay, that can mimic complex cell membrane environment more accurately, is required to explore the inherent hetero-multivalency of the cell membrane. We have thus developed a new membrane perturbation protocol to efficiently screen receptor candidates involved in hetero-multivalent protein binding.

Exosomes, the smallest sized extracellular vesicles (30 ~ 150 nm) packaged with lipids, proteins, functional messenger RNAs and microRNAs, and double-stranded DNA from their cells of origin, have emerged as key players in intercellular communication. Their presence in bodily fluids, where they protect their cargo from degradation, makes them attractive candidates for clinical application as innovative diagnostic and therapeutic tools. But routine isolation and analysis of high purity exosomes in clinical settings is challenging, with conventional methods facing a number of drawbacks including low yield and/or purity, long processing times, high cost, and difficulties in standardization. Here we review a promising solution, microfluidic-based technologies that have incorporated a host of separation and sensing capabilities for exosome isolation, detection, and analysis, with emphasis on point of care and clinical applications. These new capabilities promise to advance fundamental research while paving the way toward routine exosome-based liquid biopsy for personalized medicine.

Adaptive laboratory evolution (ALE) is a powerful tool used to increase strain fitness in the presence of environmental stressors. If production and strain fitness can be coupled, ALE can be used to increase product formation. In earlier work, carotenoids hyperproducing mutants were obtained using an ALE strategy. Here, de novo mutations were identified in hyperproducers, and reconstructed mutants were explored to determine the exact impact of each mutation on production and tolerance. A single mutation in YMRCTy1-3 conferred increased carotenoid production, and when combined with other beneficial mutations led to further increased β-carotene production. Findings also suggest that the ALE strategy selected for mutations that confer increased carotenoid production as primary phenotype. Raman spectroscopy analysis and total lipid quantification revealed positive correlation between increased lipid content and increased β-carotene production. Finally, we demonstrated that the best combinations of mutations identified for β-carotene production were also beneficial for production of lycopene.

Due to its extreme sensitivity and fingerprint specificity, surface enhanced Raman spectroscopy (SERS) is a powerful tool for substance identification. Developments in portable low-cost SERS substrates and handheld Raman spectrometers enable SERS analysis at sample origin, with great potential benefit to field-work applications in numerous disciplines. This study reports a procedure which incorporates sample collection, isolation, and SERS identification of airborne solids on a single inexpensive substrate. This procedure, vacuum filtration-paper chromatography–SERS (VF-PC-SERS), utilizes a porous filter paper decorated with plasmonic nanoparticles which we call nanopaper. The porous fiber structure facilitates both the vacuum filter powder capture and the isolation of components by paper chromatography, while the nanoplasmonic coating enhances Raman signal. One potentially high-impact application of VF-PC-SERS is field analysis of hazardous or illicit materials. This study demonstrates a proof-of-concept for VF-PC-SERS using powdered rhodamine 6G (R6G) dispersed in air, resulting in 100% detection accuracy (true positive rate) at R6G levels as low as 0.6 mg/m(3). Analysis of R6G contaminated with topsoil or lactose resulted in specific identification of R6G in powder mixtures containing as little as 0.1 wt. % R6G. This study demonstrates the feasibility of VF-PC-SERS as a safer procedure to identify hazardous substances at the point of sample origin.

Cholera toxin (CTx) has to attach to host cell membrane before it is internalized to initiate infection processes. The attachment of CTx is mediated by cholera toxin subunit B (CTB) to the ganglioside receptors in host cell membrane. Prior studies revealed the complex nature of the CTB-ganglioside binding process by examining the properties of GM1, the major CTB receptor. Other gangliosides (e.g. GD1b) exhibiting moderate binding affinities to CTB also mediate the CTx internalization process. However, due to its intrinsic complexity, the binding mechanisms of other ganglioside receptors still remain elusive. In this work, a new dynamic model is proposed to describe a multistep binding process between CTB and GD1b by considering the cooperative binding effect as well as the GD1b receptor aggregation in a cell membrane. Moreover, in order to quantitatively calibrate the model against the experimental data, a numerical scheme including the local sensitivity under uncertainty and parameter selection method is implemented to identify several important parameters to be estimated. After estimating the selected parameters, the calibrated model agreed well with the experimental measurements, which demonstrated its predictive capability in the CTB-GD1b binding process.

A single glycan-lectin interaction is often weak and semi-specific. Multiple binding domains in a single lectin can bind with multiple glycan molecules simultaneously, making it difficult for the classic “lock-and-key” model to explain these interactions. We demonstrated that hetero-multivalency, a homo-oligomeric protein simultaneously binding to at least two types of ligands, influences LecA (a Pseudomonas aeruginosa adhesin)-glycolipid recognition. We also observed enhanced binding between P. aeruginosa and mixed glycolipid liposomes. Interestingly, strong ligands could activate weaker binding ligands leading to higher LecA binding capacity. This hetero-multivalency is probably mediated via a simple mechanism, Reduction of Dimensionality (RD). To understand the influence of RD, we also modeled LecA’s two-step binding process with membranes using a kinetic Monte Carlo simulation. The simulation identified the frequency of low-affinity ligand encounters with bound LecA and the bound LecA’s retention of the low-affinity ligand as essential parameters for triggering hetero-multivalent binding, agreeing with experimental observations. The hetero-multivalency can alter lectin binding properties, including avidities, capacities, and kinetics, and therefore, it likely occurs in various multivalent binding systems. Using hetero-multivalency concept, we also offered a new strategy to design high-affinity drug carriers for targeted drug delivery.

Surface-enhanced Raman scattering (SERS) is a powerful analytical tool which enables the detection and identification of analytes adsorbed on nanostructured noble metals. However, SERS analysis of complex mixtures can be challenging due to spectral overlap and interference. In this report, we demonstrate a method to simplify the identification of mixed-analyte samples by coupling SERS detection with chromatographic separation on a nanoplasmonic paper substrate. This "nanopaper" substrate is a silver coated glass microfiber filter paper which possesses large SERS enhancement and can serve as a stationary phase in paper chromatography. Nanopaper is easily synthesized using the silver mirror reaction, making it a highly accessible technology. Nanopaper was successfully used as a combined paper chromatography-SERS (PC-SERS) substrate in the separation and identification of mixed organic dyes. It was further employed to separate and identify lycopene and β-carotene in commercial food products, demonstrating the versatility and utility of nanopaper in the identification of complex mixtures.

How cholera toxin subunit B (CTB) binds to its receptor in host cell membrane is still not fully understood due to its complex nature. In this study, a kinetic Monte Carlo (kMC) model is proposed to describe the binding kinetics between CTB and its receptor on lipid membrane. The proposed kMC model considers receptor migration, CTB attachment and detachment, and surface forward and backward reactions as discrete microscopic events. At every moment, an event to be executed is selected randomly based on the rates of all possible events, and this procedure continues till the end of simulation. By accounting for these events, the predictions from the proposed kMC model qualitatively agree with the experimental measurements.

Pancreatic cancer (PC) is an aggressive disease with high mortality rates, however, there is no blood test for early detection and diagnosis of this disease. Several research groups have reported on metabolomics based clinical investigations to identify biomarkers of PC, however there is a lack of a centralized metabolite biomarker repository that can be used for meta-analysis and biomarker validation. Furthermore, since the incidence of PC is associated with metabolic syndrome and Type 2 diabetes mellitus (T2DM), there is a need to uncouple these common metabolic dysregulations that may otherwise diminish the clinical utility of metabolomic biosignatures. Here, we attempted to externally replicate proposed metabolite biomarkers of PC reported by several other groups in an independent group of PC subjects. Our study design included a T2DM cohort that was used as a non-cancer control and a separate cohort diagnosed with colorectal cancer (CRC), as a cancer disease control to eliminate possible generic biomarkers of cancer. We used targeted mass spectrometry for quantitation of literature-curated metabolite markers and identified a biomarker panel that discriminates between normal controls (NC) and PC patients with high accuracy. Further evaluation of our model with CRC, however, showed a drop in specificity for the PC biomarker panel. Taken together, our study underscores the need for a more robust study design for cancer biomarker studies so as to maximize the translational value and clinical implementation. This work was supported by ACS IRG-92-152-17 pilot award number AWD4470404 to KU and AKC. The authors would like to acknowledge the Metabolomics Shared Resource in Georgetown University (Washington DC, USA) partially supported by NIH/NCI/CCSG grant P30-CA051008

Tuberculosis (TB) is a major global health threat, resulting in an urgent unmet need for a rapid, non–sputum-based quantitative test to detect active Mycobacterium tuberculosis (Mtb) infections in clinically diverse populations and quickly assess Mtb treatment responses for emerging drug-resistant strains. We have identified Mtb-specific peptide fragments and developed a method to rapidly quantify their serum concentrations, using antibody-labeled and energy-focusing porous discoidal silicon nanoparticles (nanodisks) and high-throughput mass spectrometry (MS) to enhance sensitivity and specificity. NanoDisk-MS diagnosed active Mtb cases with high sensitivity and specificity in a case-control study with cohorts reflecting the complexity of clinical practice. Similar robust sensitivities were obtained for cases of culture-positive pulmonary TB (PTB; 91.3%) and extrapulmonary TB (EPTB; 92.3%), and the sensitivities obtained for culture-negative PTB (82.4%) and EPTB (75.0%) in HIV-positive patients significantly outperformed those reported for other available assays. NanoDisk-MS also exhibited high specificity (87.1–100%) in both healthy and high-risk groups. Absolute quantification of serum Mtb antigen concentration was informative in assessing responses to antimycobacterial treatment. Thus, a NanoDisk-MS assay approach could significantly improve the diagnosis and management of active TB cases, and perhaps other infectious diseases as well.

Rapid screening and diagnosis of tuberculosis disease (TB) is still challenging and critically needed for global TB control efforts. In this study, we present a rapid and streamlined technology, using precisely engineered silica nanopore thin films, which are optimized for pore size, structure, capillary force, and film thickness, to isolate Mycobacterium tuberculosis (MTB) antigens in laboratory and clinical samples for rapid TB screening. This technology, referred to here as on-chip fractionation, is integrated with high-throughput matrix-assisted laser desorption/ionization time-of flight mass spectrometry to screen and identify fragments of the MTB antigen, CFP-10, from complex biological samples, without use of immunoaffinity agents. With the use of this comprehensive approach, we were able to clearly distinguish a clinical isolate of MTB from a nonTB species of the genus Mycobacterium avium grown in liquid culture media. This assay can reach a detection limit of 10 fmol and an isolation rate of 90% for the antigen CFP-10. Our strategy has significant potential to fill the conceptual and technical gaps in rapid diagnosis of active TB disease.

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool with high potential for multiplexed detection of dilute analytes. However, quantitative SERS of kinetic assays can be difficult due to the variation in enhancement factors caused by changing reaction conditions. We report a method for quantitative SERS kinetic analysis using colloidal Ag–Au core–shell nanocubes (Ag@AuNCs) as the SERS substrate. This substrate is mass producible, possesses large SERS enhancement, and is resistant to degradation in most environments. The SERS enhancement of the Ag@AuNCs was evaluated both experimentally and computationally. Quantitation was achieved by covalently attaching a non-reactive internal standard (IS) to substrate surfaces and normalizing SERS spectra to the IS signal. We demonstrated that IS normalization corrects for temporal variations in enhancement factor and particle concentration. Quantitation was demonstrated by monitoring the base-catalyzed aldol condensation of surface-bound 4-(methylthio)benzaldehyde with free acetone. The kinetic model of this reaction was fitted to IS normalized SERS data, resulting in kinetic parameters that agreed well with published values. This SERS platform is a robust and sensitive method for quantitative analysis of kinetic assays, with potential applications in many fields.

Measurements and predictions are reported to understand large variations in evanescent wave (EW) scattering intensities between different particles from the same batch of single mode, polydisperse colloids. Measured EW scattering intensity distributions are obtained for three different micrometer sized latex particles irreversibly deposited onto glass surfaces. Predicted EW scattering intensity distributions are obtained using measured particle size distributions as input in a Mie theory for the three-dimensional scattering of a sphere under EW illumination. Good agreement is observed between measured and predicted EW scattering intensity distributions using no adjustable parameters. Our results indicate how finite polydispersity together with resonant effects produce large, nonlinear intensity variations between particles that appear to be physically and chemically uniform. Our findings allow such resonant effects to be understood and exploited in EW based particle-surface characterization techniques (e.g., using total internal reflections, surface plasmons) and chemical and biomolecular sensing applications (e.g., using whispering gallery modes).

We report a new method for mapping patterned surfaces based on monitoring the interactions of freely diffusing colloidal probes with pattern features to generate measured potential energy landscapes. Evanescent wave scattering and video microscopy are used to track 3D center positions of nominal 2 microm silica colloids as they diffuse over 5-20-nm-thick patterned gold films. An analysis of ensemble-averaged particle height histograms on different pattern features using Boltzmann's equation produces local electrostatic and van der Waals potentials in good agreement with independent measurements and predictions. Absolute separation is obtained from theoretical fits to measured potential-energy profiles and direct measurement by depositing silica colloids onto gold surfaces via electrophoretic deposition. As colloidal probe and pattern feature dimensions become comparable, potential energy profiles suffer some distortion due to the increased probability of probes sampling pattern feature edges. An analysis of interfacial colloidal probe diffusion in conjunction with potential energy measurements demonstrates a consistent interpretation of dissipative and conservative forces in these measurements. Future extensions of this work should produce similar approaches for interrogating physical, chemical, and biomolecular heterogeneous/patterned surfaces and structures with diffusing colloidal probes.

This work involves the development of a novel technique that integrates total internal reflection and video microscopy methods to simultaneously measure single particle and ensemble average particle-surface interactions. For the 2 mum silica colloids and glass coverslip used in this study, particle size polydispersity is found to be a dominant factor in determining the distribution of single particle profiles about ensemble average profiles. In conjunction with this observation, chemical and physical nonuniformity are not evident in any of our measurements even with sensitivity to interactions on the order of kT. One advantage of using ensemble averaging in conjunction with time averaging is the ability to dramatically decrease the time required to measure average particle-wall interactions which scales inversely with interfacial particle concentration. A number of experimental issues are addressed in the development of this technique including (1) combining single particle distribution functions, (2) statistical sampling of distribution functions using both time and ensemble averaging, and (3) correcting overlapping scattering signals between adjacent particles. The capabilities of the ensemble averaging technique are also demonstrated to provide unique measurements of particle-surface interactions in metastable systems by selecting only height excursions of levitated particles when calculating potentials. Ultimately, this new technique provides several important advantages over single particle measurements, which provides a foundation for measuring interactions in increasingly complex interfacial systems.

Introduction: Pancreatic ductal adenocarcinoma (PDAC) represents 90% of pancreatic neoplasms and the fourth leading cause of cancer death in the United States. Recently, several research groups have focused on conducting metabolomics based clinical investigations to identify metabolite markers of PDAC. Since a central biomarker repository for PA is lacking, however, it remains challenging to delineate the total number of metabolites reported, and importantly, which bio-signatures overlap between the disparate studies. Approach: We performed an extensive literature search to delineate PDAC case-control studies reporting dysregulated metabolite biomarkers for PDAC utilizing three main sources: PubMed, EDRN and GDOC. We refined our search to 36 publications that reported blood based metabolomics/lipidomic biomarkers. Data from these studies was compiled based on up/down-regulation of specific metabolites in PDAC, study sample size, and other clinical determinants. The final list consisted of 12 metabolites (including amino acids, fatty acids and small organic acids), that were reported by two or more research groups as being dysregulated in PDAC. Of note, these 36 disparate studies were carried out using different methodologies, analyzed on diverse analytical platforms, and utilized different statistical and bioinformatics methodologies. Resultant common features, therefore, were deemed significant as candidate biomarkers for cross-validation. Next, we used stable isotope dilution multiple-reaction monitoring mass spectrometry (SID-MRM-MS) for targeted quantitation of these 12 metabolite markers in plasma samples obtained from patients that were diagnosed with PDAC and compared the same profiles to matched normal controls. Results: We delineated of a sub-set of the original 12 metabolites that showed concordance with those reported in the literature. Statistical analyses to determine the sensitivity and specificity of the resultant panel, and any influence provided by age, gender, and type 2 diabetes, on the predictive performance of the biomarker panel are ongoing. These data will be presented at the AACR meeting. Conclusion: Developing a specific and sensitive panel of blood-derived biomarkers offers a practical approach towards screening and allows increasing overall survival rates for PDAC with early diagnosis. Such disease-specific bio-signatures allow identification of molecular targets for therapeutic development; improve early treatment strategies and thereby clinical outcomes. Creating a compendium of existing biomarker data and performing cross-validation studies represent the first steps for developing clinical assays for the diagnosis and prognosis determination of PDAC. The integration of data generated from multiple analytic platforms and diverse subject cohorts is likely to help identify robust bio-signatures that would then be ready for large scale validation studies. Supported by American Cancer Society Citation Format: Hung-Jen Wu, Khyati Mehta, Smrithi S. Menon, Keith Unger, Massimo S. Fiandaca, Yassi Fallah, Mark Mapstone, Howard J. Federoff, Amrita K. Cheema. Prognostic biomarkers of PDAC - a cross-validation study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2517. doi:10.1158/1538-7445.AM2017-2517

Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras–guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average.

In this paper we present a monitor and a remote control design of a heating cloth. This design uses an insulated heating resistance wire to warm up the cloth, which includes an application either on a phone or on a handheld controller. The built-in controller monitors and controls the temperature through Bluetooth transmission. The heating pad inside the heating cloth monitors both the heating pad temperature and the body temperature. The user can instantly know the body temperature and wear clothing which can be adjusted to retain body warmth.

Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras-guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average., link_to_subscribed_fulltext

Endogenous peptides that represent biological and pathological information of disease have attracted interest for diagnosis. However, the extraction of those low abundance peptides is still a challenge because of the complexity of human bodily fluids (HBF). Hepcidin, a peptide hormone, has been recognized as a biomarker for iron-related diseases. There is no rapid and reliable way to enrich them from HBF. Here we describe a peptide extraction approach based on nanoporous silica thin films to successfully detect hepcidin from HBF. Cooperative functions of nanopore to biomolecule, including capillary adsorption, size-exclusion and electrostatic interaction, were systematically investigated to immobilize the target peptide. To promote this new approach to clinical practices, we further applied it to successfully assay the hepcidin levels in HBF provided by healthy volunteers and patients suffering from inflammation. Our finding provides a high-throughput, rapid, label-free and cost-effective detection method for capturing and quantifying low abundance peptides from HBF. From the Clinical Editor Diagnosing diseases with low concentration peptide biomarkers remains challenging. This team of authors describes a peptide extraction approach based on nanoporous silica thin films to successfully detect low concentrations of hepcidin from human body fluids collected from 119 healthy volunteers and 19 inflammation patients.

In developing embryos of some extant spiralian animals, polar lobe formation is one of the symmetry-breaking mechanisms for segregation of maternal cytoplasmic substances to certain blastomeres and not others. Polar lobe formation leads to unique early cleavage morphologies that include trilobed, J-shaped, and five-lobed structures. Fossil embryos similar to modern lobeforming embryos are recognized from the Precambrian Doushantuo Formation phosphates, Weng'an, Guizhou Province, China. These embryos are abundant and form a developmental sequence comparable to different developing stages observed in lobe-forming embryos of extant spiralians. These data imply that lobe formation is an evolutionarily ancient process of embryonic specification.

We fabricated a microfluidic device consisting of ciliated micropillars, forming a porous silicon nanowire-on-micropillar structure. We demonstrated that the prototype device can preferentially trap exosome-like lipid vesicles, while simultaneously filtering out proteins and cell debris. Trapped lipid vesicles can be recovered intact by dissolving the porous nanowires in PBS buffer.

In this paper we design a convenient wireless temperature measuring device that is intended primarily for large numbers of users, not for individual use. Temperature recording for continuous measurement can be done through Bluetooth transmission or by inserting an infrared thermo sensor into the smartphone's headphone jack. An application on a smartphone allows immediate measurement of the temperature, and both the measurement and a user's archive photo taken at the same time are sent to a remote server over the wireless network. Users can check their long-term body temperature information instantly through the Internet.