Publications by authors named "Rishikesh Pandey"

25 Publications

  • Page 1 of 1

Vibrational spectroscopy for decoding cancer microbiota interactions: Current evidence and future perspective.

Semin Cancer Biol 2021 Jul 14. Epub 2021 Jul 14.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. Electronic address:

The role of human microbiota in cancer initiation and progression is recognized in recent years. In order to investigate the interactions between cancer cells and microbes, a systematic analysis using various emerging techniques is required. Owing to the label-free, non-invasive and molecular fingerprinting characteristics, vibrational spectroscopy is uniquely suited to decode and understand the relationship and interactions between cancer and the microbiota at the molecular level. In this review, we first provide a quick overview of the fundamentals of vibrational spectroscopic techniques, namely Raman and infrared spectroscopy. Next, we discuss the emerging evidence underscoring utilities of these spectroscopic techniques to study cancer or microbes separately, and share our perspective on how vibrational spectroscopy can be employed at the intersection of the two fields. Finally, we envision the potential opportunities in exploiting vibrational spectroscopy not only in basic cancer-microbiome research but also in its clinical translation, and discuss the challenges in the bench to bedside translation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semcancer.2021.07.004DOI Listing
July 2021

Raman and quantitative phase imaging allow morpho-molecular recognition of malignancy and stages of B-cell acute lymphoblastic leukemia.

Biosens Bioelectron 2021 Oct 12;190:113403. Epub 2021 Jun 12.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA; The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Oncology, Johns Hopkins University, Baltimore, MD, 21287, USA. Electronic address:

Acute lymphoblastic leukemia (ALL) is one of the most common malignancies that account for nearly one-third of all pediatric cancers. The current diagnostic assays are time-consuming, labor-intensive, and require expensive reagents. Here, we report a label-free approach featuring diffraction phase imaging and Raman microscopy that can retrieve both morphological and molecular attributes for label-free optical phenotyping of individual B cells. By investigating leukemia cell lines of early and late stages along with the healthy B cells, we show that phase images can capture subtle morphological differences among the healthy, early, and late stages of leukemic cells. By exploiting its biomolecular specificity, we demonstrate that Raman microscopy is capable of accurately identifying not only different stages of leukemia cells but also individual cell lines at each stage. Overall, our study provides a rationale for employing this hybrid modality to screen leukemia cells using the widefield QPI and using Raman microscopy for accurate differentiation of early and late-stage phenotypes. This contrast-free and rapid diagnostic tool exhibits great promise for clinical diagnosis and staging of leukemia in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2021.113403DOI Listing
October 2021

Advancing Raman spectroscopy from research to clinic: Translational potential and challenges.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Nov 13;260:119957. Epub 2021 May 13.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD 21205, United States; Department of Oncology, Johns Hopkins University, Baltimore, MD 21287, United States. Electronic address:

Raman spectroscopy has emerged as a non-invasive and versatile diagnostic technique due to its ability to provide molecule-specific information with ultrahigh sensitivity at near-physiological conditions. Despite exhibiting substantial potential, its translation from optical bench to clinical settings has been impacted by associated limitations. This perspective discusses recent clinical and biomedical applications of Raman spectroscopy and technological advancements that provide valuable insights and encouragement for resolving some of the most challenging hurdles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.saa.2021.119957DOI Listing
November 2021

Coarse Raman and optical diffraction tomographic imaging enable label-free phenotyping of isogenic breast cancer cells of varying metastatic potential.

Biosens Bioelectron 2021 Mar 27;175:112863. Epub 2020 Nov 27.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA; The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Oncology, Johns Hopkins University, Baltimore, MD, 21287, USA. Electronic address:

Identification of the metastatic potential represents one of the most important tasks for molecular imaging of cancer. While molecular imaging of metastases has witnessed substantial progress as an area of clinical inquiry, determining precisely what differentiates the metastatic phenotype has proven to be more elusive. In this study, we utilize both the morphological and molecular information provided by 3D optical diffraction tomography and Raman spectroscopy, respectively, to propose a label-free route for optical phenotyping of cancer cells at single-cell resolution. By using an isogenic panel of cell lines derived from MDA-MB-231 breast cancer cells that vary in their metastatic potential, we show that 3D refractive index tomograms can capture subtle morphological differences among the parental, circulating tumor cells, and lung metastatic cells. By leveraging its molecular specificity, we demonstrate that coarse Raman microscopy is capable of rapidly mapping a sufficient number of cells for training a random forest classifier that can accurately predict the metastatic potential of cells at a single-cell level. We also perform multivariate curve resolution alternating least squares decomposition of the spectral dataset to demarcate spectra from cytoplasm and nucleus, and test the feasibility of identifying metastatic phenotypes using the spectra only from the cytoplasmic and nuclear regions. Overall, our study provides a rationale for employing coarse Raman mapping to substantially reduce measurement time thereby enabling the acquisition of reasonably large training datasets that hold the key for label-free single-cell analysis and, consequently, for differentiation of indolent from aggressive phenotypes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2020.112863DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7847362PMC
March 2021

Preparation and characterization of amnion hydrogel and its synergistic effect with adipose derived stem cells towards IL1β activated chondrocytes.

Sci Rep 2020 10 30;10(1):18751. Epub 2020 Oct 30.

Connecticut Convergence Institute for Translation in Regenerative Engineering, University of Connecticut Health, 263 Farmington Ave, Farmington, CT, 06030, USA.

Inflammation leads to chondrocyte senescence and cartilage degeneration, resulting in osteoarthritis (OA). Adipose-derived stem cells (ADSCs) exert paracrine effects protecting chondrocytes from degenerative changes. However, the lack of optimum delivery systems for ADSCs limits its use in the clinic. The use of extracellular matrix based injectable hydrogels has gained increased attention due to their unique properties. In the present study, we developed hydrogels from amnion tissue as a delivery system for ADSCs. We investigated the potential of amnion hydrogel to maintain ADSC functions, the synergistic effect of AM with ADSC in preventing the catabolic responses of inflammation in stimulated chondrocytes. We also investigated the role of Wnt/β-catenin signaling pathway in IL-1β induced inflammation in chondrocytes and the ability of AM-ADSC to inhibit Wnt/β-catenin signaling. Our results showed that AM hydrogels supported cell viability, proliferation, and stemness. ADSCs, AM hydrogels and AM-ADSCs inhibited the catabolic responses of IL-1β and inhibited the Wnt/β-catenin signaling pathway, indicating possible involvement of Wnt/β-catenin signaling pathways in IL-1β induced inflammation. The results also showed that the synergistic effect of AM-ADSCs was more pronounced in preventing catabolic responses in activated chondrocytes. In conclusion, we showed that AM hydrogels can be used as a potential carrier for ADSCs, and can be developed as a potential therapeutic agent for treating OA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-75921-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7603317PMC
October 2020

Identification and Staging of B-Cell Acute Lymphoblastic Leukemia Using Quantitative Phase Imaging and Machine Learning.

ACS Sens 2020 10 14;5(10):3281-3289. Epub 2020 Oct 14.

Connecticut Children's Innovation Center, University of Connecticut School of Medicine, Farmington, Connecticut 06032, United States.

Identification and classification of leukemia cells in a rapid and label-free fashion is clinically challenging and thus presents a prime arena for implementing new diagnostic tools. Quantitative phase imaging, which maps optical path length delays introduced by the specimen, has been demonstrated to discern cellular phenotypes based on differential morphological attributes. Rapid acquisition capability and the availability of label-free images with high information content have enabled researchers to use machine learning (ML) to reveal latent features. We developed a set of ML classifiers, including convolutional neural networks, to discern healthy B cells from lymphoblasts and classify stages of B cell acute lymphoblastic leukemia. Here, we show that the average dry mass and volume of normal B cells are lower than those of cancerous cells and that these morphologic parameters increase further alongside disease progression. We find that the relaxed training requirements of a ML approach are conducive to the classification of cell type, with minimal space, training time, and memory requirements. Our findings pave the way for a larger study on clinical samples of acute lymphoblastic leukemia, with the overarching goal of its broader use in hematopathology, where the prospect of objective diagnoses with minimal sample preparation remains highly desirable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acssensors.0c01811DOI Listing
October 2020

Reagent-Free and Rapid Assessment of T Cell Activation State Using Diffraction Phase Microscopy and Deep Learning.

Anal Chem 2019 03 22;91(5):3405-3411. Epub 2019 Feb 22.

Connecticut Children's Innovation Center , University of Connecticut School of Medicine , Farmington , Connecticut 06032 , United States.

CD8 T cells constitute an essential compartment of the adaptive immune system. During immune responses, naı̈ve T cells become functional, as they are primed with their cognate determinants by the antigen presenting cells. Current methods of identifying activated CD8 T cells are laborious, time-consuming and expensive due to the extensive list of required reagents. Here, we demonstrate an optical imaging approach featuring quantitative phase imaging to distinguish activated CD8 T cells from naı̈ve CD8 T cells in a rapid and reagent-free manner. We measured the dry mass of live cells and employed transport-based morphometry to better understand their differential morphological attributes. Our results reveal that, upon activation, the dry cell mass of T cells increases significantly in comparison to that of unstimulated cells. By employing deep learning formalism, we are able to accurately predict the population ratios of unknown mixed population based on the acquired quantitative phase images. We envision that, with further refinement, this label-free method of T cell phenotyping will lead to a rapid and cost-effective platform for assaying T cell responses to candidate antigens in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.analchem.8b04895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423970PMC
March 2019

High Power Density Low-Lead-Piezoceramic-Polymer Composite Energy Harvester.

IEEE Trans Ultrason Ferroelectr Freq Control 2019 Apr 15;66(4):789-796. Epub 2019 Jan 15.

Polymer-piezoceramic composites show mutual properties of piezoceramics and polymers that can be efficiently utilized in energy harvesting applications. Here we fabricated 0-3 composite films using high-performance low-lead piezoceramic (x)Bi(NiZr)O-(1-x)PbTiO (BNZ-PT) as ceramic filler and polyvinylidene fluoride (PVDF) as polymer matrix. Unlike the conventional morphotropic phase boundary piezoelectrics such as the (1-x)PbTiO-(x)PbZrO, the large piezoelectric response of the BNZ-PT can be obtained by poling-induced cubic-like-to-tetragonal phase transformation. This leads to high piezoelectric coefficient of the PVDF-BNZ-PT composite films as well as high-energy harvesting performance. Composite films with different volume fractions of ceramic showed surface power density of 1.3- [Formula: see text]/cm, and volume power density of 72.2- [Formula: see text]/cm using simple bending and unbending movements. Energy harvester in the form of cantilever fixed at both ends showed surface power density of 56.97- [Formula: see text]/cm and volume power density of 3165- [Formula: see text]/cm in response to impact pressure pulses. The generated power from the composite films is comparable to composite energy generators reported to date. The volume power density, however, is highest to the best of our knowledge among the reported 0-3 polymer-piezoceramic composite energy harvesters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/TUFFC.2019.2892974DOI Listing
April 2019

Integration of diffraction phase microscopy and Raman imaging for label-free morpho-molecular assessment of live cells.

J Biophotonics 2019 04 13;12(4):e201800291. Epub 2018 Dec 13.

Connecticut Children's Innovation Center, University of Connecticut School of Medicine, Farmington, Connecticut.

Label-free quantitative imaging is highly desirable for studying live cells by extracting pathophysiological information without perturbing cell functions. Here, we demonstrate a novel label-free multimodal optical imaging system with the capability of providing comprehensive morphological and molecular attributes of live cells. Our morpho-molecular microscopy (3M) system draws on the combined strength of quantitative phase microscopy (QPM) and Raman microscopy to probe the morphological features and molecular fingerprinting characteristics of each cell under observation. While the commonr-path geometry of our QPM system allows for highly sensitive phase measurement, the Raman microscopy is equipped with dual excitation wavelengths and utilizes the same detection and dispersion system, making it a distinctive multi-wavelength system with a small footprint. We demonstrate the applicability of the 3M system by investigating nucleated and nonnucleated cells. This integrated label-free platform has a promising potential in preclinical research, as well as in clinical diagnosis in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201800291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447451PMC
April 2019

Label-free spectrochemical probe for determination of hemoglobin glycation in clinical blood samples.

J Biophotonics 2018 10 19;11(10):e201700397. Epub 2018 Jun 19.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland.

Glycated hemoglobin, HbA1c, is an important biomarker that reveals the average value of blood glucose over the preceding 3 months. While significant recent attention has been focused on the use of optical and direct molecular spectroscopic methods for determination of HbA1c, a facile test that minimizes sample preparation needs and turnaround time still remains elusive. Here, we report a label-free approach for identifying low, mid and high-HbA1c groups in hemolysate and in whole blood samples featuring resonance Raman (RR) spectroscopy and support vector machine (SVM)-based classification of spectral patterns. The diagnostic power of RR measurements stems from its selective enhancement of hemoglobin-specific features, which simultaneously minimizes the blood matrix spectral interference and permits detection in the native solution. In this pilot study, our spectroscopic observations reveal that glycation of hemoglobin results in subtle but reproducible changes even when detected in the whole blood matrix. Leveraging SVM analysis of the principal component scores determined from the RR spectra, we show high degree of accuracy in classifying clinical specimen. We envisage that the promising findings will pave the way for more extensive clinical specimen investigations with the ultimate goal of translating molecular spectroscopy for routine point-of-care testing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201700397DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6191038PMC
October 2018

Electrostrain in excess of 1% in polycrystalline piezoelectrics.

Nat Mater 2018 05 9;17(5):427-431. Epub 2018 Apr 9.

Department of Materials Engineering, Indian Institute of Science, Bangalore, India.

Piezoelectric actuators transform electrical energy into mechanical energy, and because of their compactness, quick response time and accurate displacement, they are sought after in many applications. Polycrystalline piezoelectric ceramics are technologically more appealing than single crystals due to their simpler and less expensive processing, but have yet to display electrostrain values that exceed 1%. Here we report a material design strategy wherein the efficient switching of ferroelectric-ferroelastic domains by an electric field is exploited to achieve a high electrostrain value of 1.3% in a pseudo-ternary ferroelectric alloy system, BiFeO-PbTiO-LaFeO. Detailed structural investigations reveal that this electrostrain is associated with a combination of several factors: a large spontaneous lattice strain of the piezoelectric phase, domain miniaturization, a low-symmetry ferroelectric phase and a very large reverse switching of the non-180° domains. This insight for the design of a new class of polycrystalline piezoceramics with high electrostrains may be useful to develop alternatives to costly single-crystal actuators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41563-018-0060-2DOI Listing
May 2018

Differential diagnosis of otitis media with effusion using label-free Raman spectroscopy: A pilot study.

J Biophotonics 2018 06 17;11(6):e201700259. Epub 2018 Jan 17.

Connecticut Children's Innovation Center, University of Connecticut School of Medicine, Farmington, Connecticut.

Otitis media with effusion (OME) is an important and common condition affecting hearing in pediatric patients characterized by the presence of fluid in the middle ear space. The fluid is normally described as serous or mucoid based on differences in the fluid viscosity. The differential diagnosis of two OMEs, namely serous and mucoid is of significant clinical value because while the former is self-limiting, surgical procedure is commonly required for the latter. However, accurate identification of fluid types remains a challenging target unattainable with current clinical modalities due to unavailability of nonperturbative molecular tools. Here, we report an emerging spectroscopy approach featuring Raman scattering and multivariate analysis of spectral patterns to discern serous and mucoid fluids, obtained from pediatric patients undergoing myringotomy and tube placement, by providing information of differentially expressed molecules with high specificity. We demonstrate the feasibility of Raman spectroscopy-based approach to categorize middle ear effusion based on the characteristic spectral markers, notably of mucin, with classification accuracy of 91% and 93% for serous and mucoid, respectively. Our findings pave the way for further development of such a tool for fully noninvasive application that will lead to objective and accurate diagnosis thereby reducing unnecessary visits and surgical procedures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201700259DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423968PMC
June 2018

Ticagrelor Removal From Human Blood.

JACC Basic Transl Sci 2017 Apr 24;2(2):135-145. Epub 2017 Apr 24.

Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Gothenburg, Mölndal, Sweden.

The authors devised an efficient method for ticagrelor removal from blood using sorbent hemadsorption. Ticagrelor removal was measured in 2 sets of in vitro experiments. The first set was a first-pass experiment using bovine serum albumin (BSA) solution pre-incubated with ticagrelor, whereas the second set, performed in a recirculating manner, used human blood mixed with ticagrelor. Removal of ticagrelor from BSA solution reached values >99%. The peak removal rate was 99% and 94% from whole blood and 99.99% and 90% from plasma during 10 h and 3 to 4 h of recirculating experiments, respectively. In conclusion, hemadsorption robustly removes ticagrelor from BSA solution and human blood samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jacbts.2017.01.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113557PMC
April 2017

Noninvasive Monitoring of Blood Glucose with Raman Spectroscopy.

Acc Chem Res 2017 02 10;50(2):264-272. Epub 2017 Jan 10.

Department of Mechanical Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States.

The successful development of a noninvasive blood glucose sensor that can operate reliably over sustained periods of time has been a much sought after but elusive goal in diabetes management. Since diabetes has no well-established cure, control of elevated glucose levels is critical for avoiding severe secondary health complications in multiple organs including the retina, kidney and vasculature. While fingerstick testing continues to be the mainstay of blood glucose detection, advances in electrochemical sensing-based minimally invasive approaches have opened the door for alternate methods that would considerably improve the quality of life for people with diabetes. In the quest for better sensing approaches, optical technologies have surfaced as attractive candidates as researchers have sought to exploit the endogenous contrast of glucose, notably its absorption, scattering, and polarization properties. Vibrational spectroscopy, especially spontaneous Raman scattering, has exhibited substantial promise due to its exquisite molecular specificity and minimal interference of water in the spectral profiles acquired from the blood-tissue matrix. Yet, it has hitherto been challenging to leverage the Raman scattering signatures of glucose for prediction in all but the most basic studies and under the least demanding conditions. In this Account, we discuss the newly developed array of methodologies that address the key challenges in measuring blood glucose accurately using Raman spectroscopy and unlock new prospects for translation to sustained noninvasive measurements in people with diabetes. Owing to the weak intensity of spontaneous Raman scattering, recent research has focused on enhancement of signals from the blood constituents by designing novel excitation-collection geometries and tissue modulation methods while our attempts have led to the incorporation of nonimaging optical elements. Additionally, invoking mass transfer modeling into chemometric algorithms has not only addressed the physiological lag between the actual blood glucose and the measured interstitial fluid glucose values but also offered a powerful tool for predictive measurements of hypoglycemia. This framework has recently been extended to provide longitudinal tracking of glucose concentration without necessitating extensive a priori concentration information. These findings are advanced by the results of recent glucose tolerance studies in human subjects, which also hint at the need for designing nonlinear calibration models that can account for subject-to-subject variations in skin heterogeneity and hematocrit levels. Together, the emerging evidence underscores the promise of a blood withdrawal-free optical platform-featuring a combination of high-throughput Raman spectroscopic instrumentation and data analysis of subtle variations in spectral expression-for diabetes screening in the clinic and, ultimately, for personalized monitoring.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.accounts.6b00472DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896772PMC
February 2017

Leveraging the Attributes of -Derived Silver Nanoparticles for a Synergistic Broad-Spectrum Antimicrobial Platform.

Front Microbiol 2016 15;7:1984. Epub 2016 Dec 15.

Amity Institute of Microbial Technology, Amity University, NoidaIndia; Department of Mechanical Engineering, Johns Hopkins University, BaltimoreMD, USA.

Driven by the need to engineer robust surface coatings for medical devices to prevent infection and sepsis, incorporation of nanoparticles has surfaced as a promising avenue to enhance non-fouling efficacy. Microbial synthesis of such nanoscale metallic structures is of substantive interest as this can offer an eco-friendly, cost-effective, and sustainable route for further development. Here we present a -derived fungal route for synthesis of silver nanoparticles, which display significant antimicrobial properties when tested against six pathological bacterial strains (, and ) and three pathological fungal strains (, and ). These antimicrobial attributes were comparable to those of established antibiotics (streptomycin, tetracycline, kanamycin, and rifampicin) and fungicides (amphotericin B, fluconazole, and ketoconazole), respectively. Importantly, these nanoparticles show significant synergistic characteristics when combined with the antibiotics and fungicides to offer substantially greater resistance to microbial growth. The blend of antibacterial and antifungal properties, coupled with their intrinsic "green" and facile synthesis, makes these biogenic nanoparticles particularly attractive for future applications in nanomedicine ranging from topical ointments and bandages for wound healing to coated stents.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2016.01984DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5156874PMC
December 2016

An overview on manufactured nanoparticles in plants: Uptake, translocation, accumulation and phytotoxicity.

Plant Physiol Biochem 2017 Jan 2;110:2-12. Epub 2016 Aug 2.

D D Pant Interdisciplinary Research Laboratory, Department of Botany, University of Allahabad, Allahabad, India. Electronic address:

The unprecedented capability to control and characterize materials on the nanometer scale has led to the rapid expansion of nanostructured materials. The expansion of nanotechnology, resulting into myriads of consumer and industrial products, causes a concern among the scientific community regarding risk associated with the release of nanomaterials in the environment. Bioavailability of excess nanomaterials ultimately threatens ecosystem and human health. Over the past few years, the field of nanotoxicology dealing with adverse effects and the probable risk associated with particulate structures <100 nm in size has emerged from the recognized understanding of toxic effects of fibrous and non-fibrous particles and their interactions with plants. The present review summarizes uptake, translocation and accumulation of nanomaterials and their recognized ways of phytotoxicity on morpho-anatomical, physiological, biochemical and molecular traits of plants. Besides this, the present review also examines the intrinsic detoxification mechanisms in plants in light of nanomaterial accumulation within plant cells or parts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.plaphy.2016.07.030DOI Listing
January 2017

Facile Algae-Derived Route to Biogenic Silver Nanoparticles: Synthesis, Antibacterial, and Photocatalytic Properties.

Langmuir 2015 Oct 16;31(42):11605-12. Epub 2015 Oct 16.

Amity Institute of Microbial Technology, Amity University Uttar Pradesh , Noida, 201313, India.

Biogenic synthesis of metal nanoparticles is of considerable interest, as it affords clean, biocompatible, nontoxic, and cost-effective fabrication. Driven by their ability to withstand variable extremes of environmental conditions, several microorganisms, notably bacteria and fungi, have been investigated in the never-ending search for optimal nanomaterial production platforms. Here, we present a hitherto unexplored algal platform featuring Chlorella pyrenoidosa, which offers a high degree of consistency in morphology of synthesized silver nanoparticles. Using a suite of characterization methods, we reveal the intrinsic crystallinity of the algae-derived nanoparticles and the functional moieties associated with its surface stabilization. Significantly, we demonstrate the antibacterial and photocatalytic properties of these silver nanoparticles and discuss the potential mechanisms that drive these critical processes. The blend of photocatalytic and antibacterial properties coupled with their intrinsic biocompatibility and eco-friendliness make these nanoparticles particularly attractive for wastewater treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.5b03081DOI Listing
October 2015

Discerning the differential molecular pathology of proliferative middle ear lesions using Raman spectroscopy.

Sci Rep 2015 Aug 20;5:13305. Epub 2015 Aug 20.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.

Despite its widespread prevalence, middle ear pathology, especially the development of proliferative lesions, remains largely unexplored and poorly understood. Diagnostic evaluation is still predicated upon a high index of clinical suspicion on otoscopic examination of gross morphologic features. We report the first technique that has the potential to non-invasively identify two key lesions, namely cholesteatoma and myringosclerosis, by providing real-time information of differentially expressed molecules. In addition to revealing signatures consistent with the known pathobiology of these lesions, our observations provide the first evidence of the presence of carbonate- and silicate-substitutions in the calcium phosphate plaques found in myringosclerosis. Collectively, these results demonstrate the potential of Raman spectroscopy to not only provide new understanding of the etiology of these conditions by defining objective molecular markers but also aid in margin assessment to improve surgical outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep13305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4542608PMC
August 2015

Engineering tailored nanoparticles with microbes: quo vadis?

Wiley Interdiscip Rev Nanomed Nanobiotechnol 2016 Mar-Apr;8(2):316-30. Epub 2015 Aug 14.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA.

In the quest for less toxic and cleaner methods of nanomaterials production, recent developments in the biosynthesis of nanoparticles have underscored the important role of microorganisms. Their intrinsic ability to withstand variable extremes of temperature, pressure, and pH coupled with the minimal downstream processing requirements provide an attractive route for diverse applications. Yet, controlling the dispersity and facile tuning of the morphology of the nanoparticles of desired chemical compositions remains an ongoing challenge. In this Focus Review, we critically review the advances in nanoparticle synthesis using microbes, ranging from bacteria and fungi to viruses, and discuss new insights into the cellular mechanisms of such formation that may, in the near future, allow complete control over particle morphology and functionalization. In addition to serving as paradigms for cost-effective, biocompatible, and eco-friendly synthesis, microbes hold the promise for a unique template for synthesis of tailored nanoparticles targeted at therapeutic and diagnostic platform technologies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/wnan.1363DOI Listing
December 2016

Multi-color reflectance imaging of middle ear pathology in vivo.

Anal Bioanal Chem 2015 May 10;407(12):3277-83. Epub 2015 Mar 10.

Department of Pediatric Otolaryngology, Connecticut Children's Medical Center, Hartford, CT, 06106, USA,

Otoscopic examination using white-light illumination has remained virtually unchanged for well over a century. However, the limited contrast of white-light otoscopy constrains the ability to make accurate assessment of middle ear pathology and is subject to significant observer variability. Here, we employ a modified otoscope with multi-color imaging capabilities for superior characterization of the middle ear constituents in vivo and for enhanced diagnosis of acute otitis media and cholesteatoma. In this pilot study, five patients undergoing surgery for tympanostomy tube placement and congenital cholesteatoma excision were imaged using the custom-designed multi-color video-rate reflectance imaging system. We show that the multi-color imaging approach offers an increase in image contrast, thereby enabling clear visualization of the middle ear constituents, especially of the tympanic membrane vascularity. Differential absorption at the multiple wavelengths provides a measure of biochemical and morphological information, and the rapid acquisition and analysis of these images aids in objective evaluation of the middle ear pathology. Our pilot study shows the potential of using label-free narrow-band reflectance imaging to differentiate middle ear pathological conditions from normal middle ear. This technique can aid in obtaining objective and reproducible diagnoses as well as provide assistance in guiding excisional procedures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00216-015-8580-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748710PMC
May 2015

Emerging trends in optical sensing of glycemic markers for diabetes monitoring.

Trends Analyt Chem 2015 Jan;64:100-108

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.

In the past decade, considerable attention has been focused on the measurement of glycemic markers, such as glycated hemoglobin and glycated albumin, that provide retrospective indices of average glucose levels in the bloodstream. While these biomarkers have been regularly used to monitor long-term glucose control in established diabetics, they have also gained traction in diabetic screening. Detection of such glycemic markers is challenging, especially in a point-of-care setting, due to the stringent requirements for sensitivity and robustness. A number of non-separation based measurement strategies were recently proposed, including photonic tools that are well suited to reagent-free marker quantitation. Here, we critically review these methods while focusing on vibrational spectroscopic methods, which offer highly specific molecular fingerprinting capability. We examine the underlying principles and the utility of these approaches as reagentless assays capable of multiplexed detection of glycemic markers and also the challenges in their eventual use in the clinic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.trac.2014.09.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4295656PMC
January 2015

Spectroscopic approach for dynamic bioanalyte tracking with minimal concentration information.

Sci Rep 2014 Nov 12;4:7013. Epub 2014 Nov 12.

Laser Biomedical Research Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Vibrational spectroscopy has emerged as a promising tool for non-invasive, multiplexed measurement of blood constituents - an outstanding problem in biophotonics. Here, we propose a novel analytical framework that enables spectroscopy-based longitudinal tracking of chemical concentration without necessitating extensive a priori concentration information. The principal idea is to employ a concentration space transformation acquired from the spectral information, where these estimates are used together with the concentration profiles generated from the system kinetic model. Using blood glucose monitoring by Raman spectroscopy as an illustrative example, we demonstrate the efficacy of the proposed approach as compared to conventional calibration methods. Specifically, our approach exhibits a 35% reduction in error over partial least squares regression when applied to a dataset acquired from human subjects undergoing glucose tolerance tests. This method offers a new route at screening gestational diabetes and opens doors for continuous process monitoring without sample perturbation at intermediate time points.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep07013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4894421PMC
November 2014

Multiwavelength fluorescence otoscope for video-rate chemical imaging of middle ear pathology.

Anal Chem 2014 Oct 1;86(20):10454-60. Epub 2014 Oct 1.

Otolaryngology - Head and Neck Surgery, University of Connecticut , Storrs, Connecticut 06269, United States.

A common motif in otolaryngology is the lack of certainty regarding diagnosis for middle ear conditions, resulting in many patients being overtreated under the worst-case assumption. Although pneumatic otoscopy and adjunctive tests offer additional information, white light otoscopy has been the main tool for diagnosis of external auditory canal and middle ear pathologies for over a century. In middle ear pathologies, the inability to avail high-resolution structural and/or molecular imaging is particularly glaring, leading to a complicated and erratic decision analysis. Here, we propose a novel multiwavelength fluorescence-based video-rate imaging strategy that combines readily available optical elements and software components to create a novel otoscopic device. This modified otoscope enables low-cost, detailed and objective diagnosis of common middle ear pathological conditions. Using the detection of congenital cholesteatoma as a specific example, we demonstrate the feasibility of fluorescence imaging to differentiate this proliferative lesion from uninvolved middle ear tissue based on the characteristic autofluorescence signals. Availability of real-time, wide-field chemical information should enable more complete removal of cholesteatoma, allowing for better hearing preservation and substantially reducing the well-documented risks, costs and psychological effects of repeated surgical procedures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ac5030232DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4204905PMC
October 2014

Simultaneous detection of two triplets: a time-resolved resonance Raman study.

J Phys Chem A 2012 Aug 14;116(33):8484-9. Epub 2012 Aug 14.

Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.

Solvents are known to affect the triplet state structure and reactivity. In this paper, we have employed time-resolved resonance Raman (TR3) spectroscopy to understand solvent-induced subtle structural changes in the lowest excited triplet state of thioxanthone. Density functional theory (DFT) combined with the self-consistent reaction field (SCRF) implicit solvation model has been used to calculate the vibrational frequencies in the solvents. Here, we report a unique observation of the coexistence of two triplets, which has been substantiated by the probe wavelength-dependent Raman experiments. The coexistence of two triplets has been further supported by photoreduction experiments carried out at various temperatures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jp3047467DOI Listing
August 2012

Time-resolved resonance Raman spectroscopic studies on the triplet excited state of thioxanthone.

J Phys Chem A 2011 Jul 7;115(26):7566-73. Epub 2011 Jun 7.

Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India.

Thioxanthone has been investigated extensively owing to its unique photochemical and photophysical applications and its solvatochromic behavior. Here, we report the time-resolved resonance Raman studies on the structure of the lowest triplet excited state of thioxanthone in carbon tetrachloride. In addition, FT-IR and FT-Raman techniques have been used to study the vibrational structure in the ground state. To corroborate the experimental findings, density functional theory calculations have been carried out. Isotopic calculations and normal coordinate analysis have been used to help in assigning the observed bands to Raman vibrational modes. Structural information derived from this study is expected to help in better understanding the triplet state photochemistry of thioxanthone.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jp202387vDOI Listing
July 2011
-->