Biomedical Investigations Research Articles

Ethosomal Curcumin Promoted Wound Healing and Reduced Bacterial Flora in Second Degree Burn in Rat

Background: Curcumin is well known in biomedical investigations with an extensive antimicrobial properties and wound repair effect. However, clinical criteria recommend curcumin should be formulated for topical medication. Material and method: In this study, we prepared Ethosomal curcumin (Etho-cur) formulation for wound healing and bacterial flora assessments in treated rats which were subjected to second degree burn under a standard procedure. Results: Applying once daily of Etho-cur (0.2%) topically on rat's dorsal for 14 days significantly recovered main aspects of wound repair including re-epithelization (P<0.01), neovascularization (P<0.01), collagen synthesis (P<0.001), granulation tissue formation (P<0.001) compared with control. Considerable wound contraction was occurred by Etho-cur treatment sooner than other groups and after 16 days it was completed with a significant (P<0.001) value. Furthermore, ethosomal formulation of curcumin similar to silver sulfadiazine (SSD) cream 1% potentially inhibited (P<0.001) growth of the burn bacterial flora including Pseudomonas aeruginosa as predominant bacteria among experimental isolations during 14 days treatment. Also, antibacterial activity of Etho-cur was estimated approximately 11% more potent than free curcumin in reduction of the burn bacterial flora. Conclusion: Regarding the results, ethosomal curcumin efficiently fights against wound infection and promotes wound repair in burn injuries in rats.

The Ontology of Biological and Clinical Statistics (OBCS) for standardized and reproducible statistical analysis.

BackgroundStatistics play a critical role in biological and clinical research. However, most reports of scientific results in the published literature make it difficult for the reader to reproduce the statistical analyses performed in achieving those results because they provide inadequate documentation of the statistical tests and algorithms applied. The Ontology of Biological and Clinical Statistics (OBCS) is put forward here as a step towards solving this problem.ResultsThe terms in OBCS including ‘data collection’, ‘data transformation in statistics’, ‘data visualization’, ‘statistical data analysis’, and ‘drawing a conclusion based on data’, cover the major types of statistical processes used in basic biological research and clinical outcome studies. OBCS is aligned with the Basic Formal Ontology (BFO) and extends the Ontology of Biomedical Investigations (OBI), an OBO (Open Biological and Biomedical Ontologies) Foundry ontology supported by over 20 research communities. Currently, OBCS comprehends 878 terms, representing 20 BFO classes, 403 OBI classes, 229 OBCS specific classes, and 122 classes imported from ten other OBO ontologies.We discuss two examples illustrating how the ontology is being applied. In the first (biological) use case, we describe how OBCS was applied to represent the high throughput microarray data analysis of immunological transcriptional profiles in human subjects vaccinated with an influenza vaccine. In the second (clinical outcomes) use case, we applied OBCS to represent the processing of electronic health care data to determine the associations between hospital staffing levels and patient mortality. Our case studies were designed to show how OBCS can be used for the consistent representation of statistical analysis pipelines under two different research paradigms. Other ongoing projects using OBCS for statistical data processing are also discussed.The OBCS source code and documentation are available at: https://github.com/obcs/obcs.ConclusionsThe Ontology of Biological and Clinical Statistics (OBCS) is a community-based open source ontology in the domain of biological and clinical statistics. OBCS is a timely ontology that represents statistics-related terms and their relations in a rigorous fashion, facilitates standard data analysis and integration, and supports reproducible biological and clinical research.

Extended microbiological characterization of Göttingen minipigs: porcine cytomegalovirus and other viruses.

To prevent transmission of zoonotic microorganisms from pig transplants to human recipients when performing xenotransplantation using pig cells, tissues, or organs, donor pigs have to be carefully characterized. Göttingen minipigs (GöMP) are often used for various biomedical investigations and are well characterized concerning the presence of numerous bacteria, fungi, viruses, and parasites. Recently, we studied the prevalence and expression of porcine endogenous retroviruses and the prevalence of hepatitis E virus (HEV) in GöMP. Here, we studied the presence of the porcine cytomegalovirus (PCMV) and porcine lymphotropic herpesviruses (PLHV) and extended testing for hepatitis E virus (HEV). PCR, nested PCR, real-time PCR, real-time RT-PCR, and Western blot analyses were used to estimate the prevalence of PCMV, PLHV-1, PLHV-2, PLHV-3, and HEV. Using different PCR methods, and different source materials, PCMV was found in 10 of 26 adult GöMP, which had been derived originally by cesarean section and kept under specified pathogen-free conditions. Only highly sensitive methods gave positive results, not methods of lower sensitivity. The virus load in all positive animals was low (<100-200 copies per mL). PLHV-1, PLHV-2, and PLHV-3 were not detected by PCR; however, an anti-PLHV immune response was found in one of 10 animals tested by Western blot analyses. HEV was detected by RT-PCR in two of nine tested animals, but no anti-HEV immune response was observed. Using highly sensitive methods, PCMV, HEV, and PLHV were found in some GöMP, suggesting that these viruses may be introduced through the placenta. The results show that highly sensitive methods are required to characterize pigs to be used for xenotransplantation to prevent virus transmission.

TRI_tool: a web-tool for prediction of protein-protein interactions in human transcriptional regulation.

http://www.vin.bg.ac.rs/180/tools/tfpred.php CONTACT: vladaper@vinca.rs; nevenav@vinca.rsSupplementary information: Supplementary data are available at Bioinformatics online.

"Exploring knowledge-user experiences in integrated knowledge translation: a biomedical investigation of the causes and consequences of food allergy".

Plain English summaryPlain English summaryFood allergy is a serious public health problem in Canada and other high-income countries, as it is potentially life threatening and severely impacts the quality of life for individuals and their families. Yet, many questions still remain as to its origins and determinants, and the best practices for treatment. Formed to tackle these very questions, the GET-FACTS research study centers on a novel concept in biomedical research: in order to make this science useful, knowledge creation must include meaningful interactions with knowledge-users. With this, knowledge-users are present at every stage of the research and are crucial, central and equal contributors. This study reflects on the early part of that journey from the perspective of the knowledge-users. We conducted interviews with all non-scientist members of the GET-FACTS steering committee, representing Canadian organizations that deal with patient advocacy and policy with regards to food allergy. Steering committee members had a clear sense that scientists and knowledge-users are equally responsible for putting knowledge into action and the importance of consulting and integrating knowledge-users throughout research. They also have high expectations for the GET-FACTS integrated process; that this model of doing science will create better scientists (e.g. improve communication skills) and make the scientific output more useful and relevant. Our work highlights both the unique contributions that knowledge-users can offer to knowledge creation as well as the challenges of trying to unify members from such different communities (policy/advocacy and biomedical science). There remains a real need to develop more touch points and opportunities for collaboration if true integration is to be achieved. Despite the obstacles, this model can help change the way knowledge is created in the biomedical world.ᅟBackgroundDespite the burden of food allergic disease many questions remain as to its origins, determinants and best practices for treatment. Formed to tackle these very questions, the GET-FACTS (Genetics, Environment and Therapies: Food Allergy Clinical Tolerance Studies) research study centers around a novel concept in biomedical research: in order to make this science useful, knowledge creation must include meaningful interactions with knowledge-users, known as Integrated Knowledge Translation (IKT). In IKT, knowledge-users are present at every stage of the research and are crucial, central and equal contributors. This paper contributes to this exciting form of research by reflecting on the beginning of that journey from the perspective of the knowledge-users.MethodsSemi structured in-depth interviews were conducted in year 2 of the 5 year GET-FACTS project with all (n = 9) non-scientist members of the GET-FACTS steering committee, representing Canadian organizations that deal with patient advocacy and policy with regards to food allergy. Transcripts were coded and organized by themes developed both deductively and inductively.ResultsSteering committee members indicated a clear sense that scientists and knowledge-users are equally responsible for the translation of knowledge into action and the importance of consulting and integrating knowledge-users throughout research. Overall, these knowledge-users have very high expectations for the GET-FACTS IKT process; they feel that this model of doing science will create better scientists (e.g. improve communication skills) and make the resulting science more useful and relevant; indeed, they reported that this model of knowledge creation can be paradigm shifting.ConclusionsThis study highlights both the unique contributions that knowledge-users can offer to knowledge creation as well as the challenges of trying to unify members from such different communities (policy/advocacy and biomedical science). While our steering committee has a strong conceptual grasp on IKT and vision for their contributions, execution is not without challenges. There remains a real need to develop more touch points and opportunities for collaboration if true integration is to be achieved. Despite the obstacles, the GET-FACTS IKT model represents a new approach to knowledge creation in Canadian biomedical research and can help foster a culture of openness to participant involvement.

Generation of human muscle fibers and satellite-like cells from human pluripotent stem cells in vitro.

Progress toward finding a cure for muscle diseases has been slow because of the absence of relevant cellular models and the lack of a reliable source of muscle progenitors for biomedical investigation. Here we report an optimized serum-free differentiation protocol to efficiently produce striated, millimeter-long muscle fibers together with satellite-like cells from human pluripotent stem cells (hPSCs) in vitro. By mimicking key signaling events leading to muscle formation in the embryo, in particular the dual modulation of Wnt and bone morphogenetic protein (BMP) pathway signaling, this directed differentiation protocol avoids the requirement for genetic modifications or cell sorting. Robust myogenesis can be achieved in vitro within 1 month by personnel experienced in hPSC culture. The differentiating culture can be subcultured to produce large amounts of myogenic progenitors amenable to numerous downstream applications. Beyond the study of myogenesis, this differentiation method offers an attractive platform for the development of relevant in vitro models of muscle dystrophies and drug screening strategies, as well as providing a source of cells for tissue engineering and cell therapy approaches.

Nature of phosphorescence kinetics of xanthene dyes in biological media

In the paper the experimental results on the nature of the phosphorescence of xanthene dyes in biological media are discussed. Phosphorescence is a monomolecular process and should have exponential type. However, the kinetics of the phosphorescence of xanthene dyes has two-exponential type in biological media. Analysis of data by experimental and theoretical methods showed that the second exponent connects on the phosphorescence of dye dimers. It can be used in biomedical investigation for dose selection of preparation delivery.

A Wearable Sensor System with Circadian Rhythm Stability Estimation for Prototyping Biomedical Studies

Despite recent growth in the field of wearable devices, persistent collection of data with clear biomedical relevance remains elusive. The majority of products focus on short-term personal fitness metrics instead of long-term biomedical monitoring. The ideal wearable platform for researchers would include flexibility to test different biometric sensors. We present an open-source, modifiable, and user-reconfigurable wearable sensor system capable of enabling biomedical investigations not feasible with currently-available devices. Our armband device has been configured to measure skin temperature, light, and activity across days to detect internal circadian rhythms. Instability of circadian rhythms is linked to risk of many diseases, including mental illness such as depression, and has predictive power for personal affective state, yet its clinical use is slow in adoption in part because of the difficulty in acquiring relevant data. We provide evidence that such measurements are attainable at high resolution, low cost, and with minimal subject burden. Our device was tested with a variety of other sensors, and results indicate that daily circadian stability and hourly ultradian rhythms in core body temperature and hormone concentrations can be predicted from armband data. Future devices will be self-powered and perform automatic data collection to improve data continuity.

Islet cell transplantation from Göttingen minipigs to cynomolgus monkeys: analysis of virus safety.

Xenotransplantation using pig cells, tissues or organs may be associated with the transmission of porcine zoonotic micro-organisms. Hepatitis E virus (HEV), porcine cytomegalovirus (PCMV) and porcine endogenous retroviruses (PERVs) are potentially zoonotic micro-organisms which do not show clinical symptoms in pigs and which are due to the low expression level difficult to detect. Göttingen Minipigs (GöMP) are often used for biomedical investigations and they are well characterized concerning the presence of numerous bacteria, fungi, viruses and parasites and therefore may be used for islet cell transplantation. Islet cells derived from three GöMP were transplanted into four healthy, non-diabetic cynomolgus monkeys using a macroencapsulation device. PCR, nested PCR, real-time PCR, real-time RT-PCR and Western blot analyses were used to estimate the presence of PERV, PCMV and HEV in the donors and recipients. Using sensitive detection methods, no HEV was found in the donor pigs and in the pig islet cell preparations. Antibodies against PERV, PCMV and HEV were not found in all cynomolgus monkeys with exception of one monkey showing an immune response against HEV. Using real-time PCR, no PCMV and HEV were found in the sera of all monkeys. Although the donor islet cells and the recipients were negative for HEV using PCR and Western blot analysis, in one recipient, antibodies against HEV were found, indicating infection in a single case. All recipients were negative for antibodies against PERV, and all were negative for PCMV, indicating absence of infection. As HEV was not detected in the donor pig before transplantation, a more complex and regular screening of the animals using highly sensitive methods is required to avoid virus transmission.

Recent Developments in Diffusion Tensor Imaging of Brain.

Magnetic resonance imaging (MRI) has come to be known as a unique radiological imaging modality because of its ability to perform tomographic imaging of body without the use of any harmful ionizing radiation. The radiologists use MRI to gain insight into the anatomy of organs, including the brain, while biomedical researchers explore the modality to gain better understanding of the brain structure and function. However, due to limited resolution and contrast, the conventional MRI fails to show the brain microstructure. Diffusion tensor imaging (DTI) harnesses the power of conventional MRI to deduce the diffusion dynamics of water molecules within the tissue and indirectly create a three-dimensional sketch of the brain anatomy. DTI enables visualization of brain tissue microstructure, which is extremely helpful in understanding various neuropathologies and neurodegenerative disorders. In this review, we briefly discuss the background and operating principles of DTI, followed by current trends in DTI applications for biomedical and clinical investigation of various brain diseases and disorders.

An integrated signal transduction network of macrophage migration inhibitory factor.

Macrophage migration inhibitory factor (MIF) is a glycosylated multi-functional protein that acts as an enzyme as well as a cytokine. MIF mediates its actions through a cell surface class II major histocompatibility chaperone, CD74 and co-receptors such as CD44, CXCR2, CXCR4 or CXCR7. MIF has been implicated in the pathogenesis of several acute and chronic inflammatory diseases. Although MIF is a molecule of biomedical importance, a public resource of MIF signaling pathway is currently lacking. In view of this, we carried out detailed data mining and documentation of the signaling events pertaining to MIF from published literature and developed an integrated reaction map of MIF signaling. This resulted in the cataloguing of 68 molecules belonging to MIF signaling pathway, which includes 24 protein-protein interactions, 44 post-translational modifications, 11 protein translocation events and 8 activation/inhibition events. In addition, 65 gene regulation events at the mRNA levels induced by MIF signaling have also been catalogued. This signaling pathway has been integrated into NetPath ( http://www.netpath.org ), a freely available human signaling pathway resource developed previously by our group. The MIF pathway data is freely available online in various community standard data exchange formats. We expect that data on signaling events and a detailed signaling map of MIF will provide the scientific community with an improved platform to facilitate further molecular as well as biomedical investigations on MIF.

The Ontology for Biomedical Investigations.

The Ontology for Biomedical Investigations (OBI) is an ontology that provides terms with precisely defined meanings to describe all aspects of how investigations in the biological and medical domains are conducted. OBI re-uses ontologies that provide a representation of biomedical knowledge from the Open Biological and Biomedical Ontologies (OBO) project and adds the ability to describe how this knowledge was derived. We here describe the state of OBI and several applications that are using it, such as adding semantic expressivity to existing databases, building data entry forms, and enabling interoperability between knowledge resources. OBI covers all phases of the investigation process, such as planning, execution and reporting. It represents information and material entities that participate in these processes, as well as roles and functions. Prior to OBI, it was not possible to use a single internally consistent resource that could be applied to multiple types of experiments for these applications. OBI has made this possible by creating terms for entities involved in biological and medical investigations and by importing parts of other biomedical ontologies such as GO, Chemical Entities of Biological Interest (ChEBI) and Phenotype Attribute and Trait Ontology (PATO) without altering their meaning. OBI is being used in a wide range of projects covering genomics, multi-omics, immunology, and catalogs of services. OBI has also spawned other ontologies (Information Artifact Ontology) and methods for importing parts of ontologies (Minimum information to reference an external ontology term (MIREOT)). The OBI project is an open cross-disciplinary collaborative effort, encompassing multiple research communities from around the globe. To date, OBI has created 2366 classes and 40 relations along with textual and formal definitions. The OBI Consortium maintains a web resource (http://obi-ontology.org) providing details on the people, policies, and issues being addressed in association with OBI. The current release of OBI is available at http://purl.obolibrary.org/obo/obi.owl.

Rail-dbGaP: analyzing dbGaP-protected data in the cloud with Amazon Elastic MapReduce.

Motivation: Public archives contain thousands of trillions of bases of valuable sequencing data. More than 40% of the Sequence Read Archive is human data protected by provisions such as dbGaP. To analyse dbGaP-protected data, researchers must typically work with IT administrators and signing officials to ensure all levels of security are implemented at their institution. This is a major obstacle, impeding reproducibility and reducing the utility of archived data.Results: We present a protocol and software tool for analyzing protected data in a commercial cloud. The protocol, Rail-dbGaP, is applicable to any tool running on Amazon Web Services Elastic MapReduce. The tool, Rail-RNA v0.2, is a spliced aligner for RNA-seq data, which we demonstrate by running on 9662 samples from the dbGaP-protected GTEx consortium dataset. The Rail-dbGaP protocol makes explicit for the first time the steps an investigator must take to develop Elastic MapReduce pipelines that analyse dbGaP-protected data in a manner compliant with NIH guidelines. Rail-RNA automates implementation of the protocol, making it easy for typical biomedical investigators to study protected RNA-seq data, regardless of their local IT resources or expertise.Availability and Implementation: Rail-RNA is available from http://rail.bio. Technical details on the Rail-dbGaP protocol as well as an implementation walkthrough are available at https://github.com/nellore/rail-dbgap. Detailed instructions on running Rail-RNA on dbGaP-protected data using Amazon Web Services are available at http://docs.rail.bio/dbgap/.Contacts: anellore@gmail.com or langmea@cs.jhu.eduSupplementary information: Supplementary data are available at Bioinformatics online.

An accurate and precise representation of drug ingredients.

BackgroundIn previous work, we built the Drug Ontology (DrOn) to support comparative effectiveness research use cases. Here, we have updated our representation of ingredients to include both active ingredients (and their strengths) and excipients. Our update had three primary lines of work: 1) analysing and extracting excipients, 2) analysing and extracting strength information for active ingredients, and 3) representing the binding of active ingredients to cytochrome P450 isoenzymes as substrates and inhibitors of those enzymes.MethodsTo properly differentiate between excipients and active ingredients, we conducted an ontological analysis of the roles that various ingredients, including excipients, have in drug products. We used the value specification model of the Ontology for Biomedical Investigations to represent strengths of active ingredients and then analyzed RxNorm to extract excipient and strength information and modeled them according to the results of our analysis. We also analyzed and defined dispositions of molecules used in aggregate as active ingredients to bind cytochrome P450 isoenzymes.ResultsOur analysis of excipients led to 17 new classes representing the various roles that excipients can bear. We then extracted excipients from RxNorm and added them to DrOn for branded drugs. We found excipients for 5,743 branded drugs, covering ~27 % of the 21,191 branded drugs in DrOn.Our analysis of active ingredients resulted in another new class, active ingredient role. We also extracted strengths for all types of tablets, capsules, and caplets, resulting in strengths for 5,782 drug forms, covering ~41 % of the 14,035 total drug forms and accounting for ~97 % of the 5,970 tablets, capsules, and caplets in DrOn.We represented binding-as-substrate and binding-as-inhibitor dispositions to two cytochrome P450 (CYP) isoenzymes (CYP2C19 and CYP2D6) and linked these dispositions to 65 compounds. It is now possible to query DrOn automatically for all drug products that contain active ingredients whose molecular grains inhibit or are metabolized by a particular CYP isoenzyme.DrOn is open source and is available at http://purl.obolibrary.org/obo/dron.owl.

(Invited) Phosphorus Complexes of Corrole

Metal complexes of corrole continue to attract the interest of different research groups, since the coordination chemistry of such a macrocycle presents peculiar and intriguing characteristics, such as for example its non-innocent character as a ligand. The Periodic Table of Metallocorrolates has been widely expanded in recent years, including also main group elements. Among them, phosphorus complexes of corrole have been of particular interest, since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We have recently developed different pathway for the selective introduction of different substituents in the peripheral positions of phosphorus triarylcorrole complexes. The characterization of such a complexes showed some peculiar properties, such as for example an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.

Change of photosensitizer fluorescence at its diffusion in viscous liquid flow

In this paper, the mathematical model of distribution of the injected compound in biological liquid flow has been described. It is considered that biological liquid contains a few phases such as water, peptides and cells. The injected compound (for example, photosensitizer) can interact with peptides and cells. At the time, viscosity of the biological liquid depends on pathology present in organism. The obtained distribution of the compound connects on changes of its fluorescence spectra which are registered during fluorescent diagnostics of tumors. It is obtained that the curves do not have monotonic nature. There is a sharp curves decline in the first few seconds after injection. Intensivity of curves rises after decreasing. It is especially pronounced for wavelength 590[Formula: see text]nm and 580[Formula: see text]nm (near the “transparency window” of biological tissues). Time of inflection point shifts from 8.4[Formula: see text]s to 6.9[Formula: see text]s for longer wavelength. However, difference between curves is little for different viscosity means of the biological liquid. Thus, additional pathology present in organism does not impact to the results of in vivo biomedical investigations.

Selective nitration and bromination of surprisingly ruffled phosphorus corroles

Phosphorus complexes of corrole have recently attracted increasing interest since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We report here the reactivity of the phosphorus complex of 5,10,15-tritolylcorrole in the nitration or bromination reaction. Both these attempts were successful, allowing the preparation of substituted phosphorus corroles, which can be used as intermediates of more complex architectures endowed with useful properties. Furthermore, the crystallographic characterization of both complexes shows that they have an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.

Development of 3D Printed Devices to Extract DNA Molecules for Genome Analysis

The high-throughput analysis of individual DNA is altering the pace and scope of biomedical investigation. Personal genomics will require large ensembles of individual genomes to develop a database of genomic variations. Within the human genome, more base pairs are altered as a result of structural variation than point mutations (Eichler et al., Nature Rev. Gen., 2011, 12, 363). In order to ascertain larger variations or large complex variations in human cancer genome, longer molecules (average molecule size > 700 kb) are necessary. In this regard, the Optical Mapping System (Teague et al., PNAS, 2010, 107, 10848) and Nanocoding (Jo et al., PNAS, 2007, 104, 2673; Kounovsky-Shafer, et al., Macromolecules, 2013, 46, 8356) were developed as a single molecule platform for construction of physical maps that span entire genomes. However, even these platforms find it difficult to span across large (>400 kb) complex genomic regions. The main goal of our research is to develop devices to elute DNA molecules from a gel matrix—prevents shearing of DNA molecules during cell lysis—and concentrate extremely long DNA molecules (>700 kb). Therefore, we are leveraging 3D printing to fabricate meso-fluidic devices to elute lambda DNA from gel using an electric field. For these devices, dimensions of the devices are varied in channel width; whereas, height and length of the device remains constant. In order to ascertain the device that elutes the highest concentration of lambda DNA, we are using a multi-prong approach: measuring fluorescence intensity of YOYO-1 stained DNA that are eluted into solution, as well as the fluorescence intensity of YOYO-1 stained DNA that are within gel matrix during the experiment, and measuring the concentration of DNA that remains in the gel matrix after the conclusion of the experiment using gel electrophoresis.

Training the next generation of biomedical investigators in glycosciences.

This position statement originated from a working group meeting convened on April 15, 2015, by the NHLBI and incorporates follow-up contributions by the participants as well as other thought leaders subsequently consulted, who together represent research fields relevant to all branches of the NIH. The group was deliberately composed not only of individuals with a current research emphasis in the glycosciences, but also of many experts from other fields, who evinced a strong interest in being involved in the discussions. The original goal was to discuss the value of creating centers of excellence for training the next generation of biomedical investigators in the glycosciences. A broader theme that emerged was the urgent need to bring the glycosciences back into the mainstream of biology by integrating relevant education into the curricula of medical, graduate, and postgraduate training programs, thus generating a critical sustainable workforce that can advance the much-needed translation of glycosciences into a more complete understanding of biology and the enhanced practice of medicine.

Developing High-Speed AFM and Nanomechanical Characterizations for Biomedical Investigations

Atomic force microscopy (AFM) is an advanced tool that enables the visualization of dynamic behaviors and the quantification of mechanical properties under physiological conditions of biological samples from macromolecules to cells and beyond. We have constructed a high-speed AFM toward a temporal resolution of 1s or shorter using a digital versatile disc (DVD) pickup head to detect deflections from a small cantilever. In addition, a flexure-guided scanner and a sinusoidal scan method were implemented to reach 100 line/s scan rate and successful images of clathrin cages and amyloid-β fibrils in buffers. To better define nanomechanical properties of biomedical samples ranging from nanomedicine constructs to live cells and EMC-like matrices (1), we have relied on optimizing commercial AFM systems and on using force-volume and quantitative nanomechanical mapping methods. This work showcases the value of high-speed and quantitative AFM in visualizing dynamic biological behavior at nanometer scale and in defining nanomechanical properties for understanding fundamental biomedical questions. Ref (1) “Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions,” Doyle AD, Carvajal N, Jin A, Matsumoto K, and Yamada KM, Nature Commun., in press (2015).