Detection, Mapping, and Quantification of Single Walled Carbon Nanotubes in Histological Specimens with Photoacoustic Microscopy

Contains fulltext : 110845.pdf (publisher's version ) (Open Access)AIMS: In the present study, the efficacy of multi-scale photoacoustic microscopy (PAM) was investigated to detect, map, and quantify trace amounts [nanograms (ng) to micrograms (microg)] of SWCNTs in a variety of histological tissue specimens consisting of cancer and benign tissue biopsies (histological specimens from implanted tissue engineering scaffolds). MATERIALS AND METHODS: Optical-resolution (OR) and acoustic-resolution (AR)--Photoacoustic microscopy (PAM) was employed to detect, map and quantify the SWCNTs in a variety of tissue histological specimens and compared with other optical techniques (bright-field optical microscopy, Raman microscopy, near infrared (NIR) fluorescence microscopy). RESULTS: Both optical-resolution and acoustic-resolution PAM, allow the detection and quantification of SWCNTs in histological specimens with scalable spatial resolution and depth penetration. The noise-equivalent detection sensitivity to SWCNTs in the specimens was calculated to be as low as approximately 7 pg. Image processing analysis further allowed the mapping, distribution, and quantification of the SWCNTs in the histological sections. CONCLUSIONS: The results demonstrate the potential of PAM as a promising imaging technique to detect, map, and quantify SWCNTs in histological specimens, and could complement the capabilities of current optical and electron microscopy techniques in the analysis of histological specimens containing SWCNTs

Computer-aided vaccine designing approach against fish pathogens Edwardsiella tarda and Flavobacterium columnare using bioinformatics softwares

Radha Mahendran,1 Suganya Jeyabaskar,1 Gayathri Sitharaman,1 Rajamani Dinakaran Michael,2 Agnal Vincent Paul1 1Department of Bioinformatics, 2Centre for Fish Immunology, School of Life Sciences, Vels University, Pallavaram, Chennai, Tamil Nadu, India Abstract: Edwardsiella tarda and Flavobacterium columnare are two important intracellular pathogenic bacteria that cause the infectious diseases edwardsiellosis and columnaris in wild and cultured fish. Prediction of major histocompatibility complex (MHC) binding is an important issue in T-cell epitope prediction. In a healthy immune system, the T-cells must recognize epitopes and induce the immune response. In this study, T-cell epitopes were predicted by using in silico immunoinformatics approach with the help of bioinformatics tools that are less expensive and are not time consuming. Such identification of binding interaction between peptides and MHC alleles aids in the discovery of new peptide vaccines. We have reported the potential peptides chosen from the outer membrane proteins (OMPs) of E. tarda and F. columnare, which interact well with MHC class I alleles. OMPs from E. tarda and F. columnare were selected and analyzed based on their antigenic and immunogenic properties. The OMPs of the genes TolC and FCOL_04620, respectively, from E. tarda and F. columnare were taken for study. Finally, two epitopes from the OMP of E. tarda exhibited excellent protein–peptide interaction when docked with MHC class I alleles. Five epitopes from the OMP of F. columnare had good protein–peptide interaction when docked with MHC class I alleles. Further in vitro studies can aid in the development of potential peptide vaccines using the predicted peptides. Keywords: E. tarda, F. columnare, edwardsiellosis, columnaris, T-cell epitopes, MHC class I, peptide vaccine, outer membrane proteins&nbsp

Physicochemical characterization of a novel graphene-based magnetic resonance imaging contrast agent

Shruti Kanakia,1 Jimmy D Toussaint,1 Sayan Mullick Chowdhury,1 Gaurav Lalwanim,1 Tanuf Tembulkar,1 Terry Button,1,2 Kenneth R Shroyer,3 William Moore,2 Balaji Sitharaman11Department of Biomedical Engineering, 2Department of Radiology, 3Department of Pathology, Stony Brook University, Stony Brook, NY, USAAbstract: We report the synthesis and characterization of a novel carbon nanostructure-based magnetic resonance imaging contrast agent (MRI CA); graphene nanoplatelets intercalated with manganese (Mn2+) ions, functionalized with dextran (GNP-Dex); and the in vitro assessment of its essential preclinical physicochemical properties: osmolality, viscosity, partition coefficient, protein binding, thermostability, histamine release, and relaxivity. The results indicate that, at concentrations between 0.1 and 100.0 mg/mL, the GNP-Dex formulations are hydrophilic, highly soluble, and stable in deionized water, as well as iso-osmolar (upon addition of mannitol) and iso-viscous to blood. At potential steady-state equilibrium concentrations in blood (0.1–10.0 mg/mL), the thermostability, protein-binding, and histamine-release studies indicate that the GNP-Dex formulations are thermally stable (with no Mn2+ ion dissociation), do not allow non-specific protein adsorption, and elicit negligible allergic response. The r1 relaxivity of GNP-Dex was 92 mM-1s-1 (per-Mn2+ ion, 22 MHz proton Larmor frequency); ~20- to 30-fold greater than that of clinical gadolinium (Gd3+)- and Mn2+-based MRI CAs. The results open avenues for preclinical in vivo safety and efficacy studies with GNP-Dex toward its development as a clinical MRI CA.Keywords: manganese, dextran, preclinical, physicochemical properties, relaxivity, graphene, magnetic resonance imaging, contrast agen

Concentration-dependent photoacoustic signals produced by single walled carbon nanotubes (SWCNTs).

<p>For each concentration, 3 spots were spotted. In each spot, the photoacoustic signal signals of all the trace amounts of SWCNTs are integrated and represented as the total photoacoustic signal. Then the average photoacoustic signal and the standard deviation were obtained from the three spots of each concentration. The noise-equivalent mass sensitivity was calculated based on the quantification of the average noise level per resolution voxel. The photoacoustic signals of all the above concentrations were used to generate the standard curve in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035064#pone-0035064-g002" target="_blank">Fig. 2</a>.</p

Comparison between conventional transmission-mode optical microscopy and optical-resolution photoacoustic microscopy (OR-PAM) of subcutaneous rabbit tissue implanted with poly(propylene fumarate) (PPF) scaffold for 12 weeks and labeled with SWCNTs.

<p>(a) The optical image and (b) the OR-PAM image of methylene blue and basic fuchsin stained subcutaneous rabbit tissue with SWCNTs. (c) Image processed using the SCANCO software by subtracting the background signal of the breast tissue. The SWCNTs appear as black aggregates (NT), the blue stained areas represent the connective tissue CT, and ‘P’ represents the PPF scaffold in the optical images.</p