Measuring three dimensional strain and structural defects in a single InGaAs nanowire using coherent x-ray multi-angle Bragg projection ptychography.
Nano Lett. 2018 Jan 18;:
Authors: Hill MO, Calvo-Almazan I, Allain M, Holt M, Ulvestad A, Treu J, Koblmueller G, Huang C, Huang X, Yan H, Nazarestski E, Chu YS, Stephenson GB, Chamard V, Lauhon L, Hruszkewycz SO
III-As nanowires are candidates for near infrared light emitters and detectors that can be directly integrated onto silicon. However, nanoscale to microscale variations in structure, composition, and strain within a given nanowire, as well as variations between nanowires, pose challenges to correlating microstructure with device performance. In this work, we utilize coherent nano-focused x-rays to characterize stacking defects and strain in a single InGaAs nanowire supported on Si. By reconstructing diffraction patterns from the 2-1-10 Bragg peak, we show that the lattice orientation varies along the length of the wire, while the strain field along the cross-section is largely unaffected, leaving the band structure unperturbed. Diffraction patterns from the 01-10 Bragg peak are reproducibly reconstructed to create three-dimensional images of stacking defects and associated lattice strains, revealing sharp planar boundaries between different crystal phases of wurtzite (WZ) structure that contribute to charge carrier scattering. Phase retrieval is made possible by developing multi-angle Bragg projection ptychography (maBPP) to accommodate coherent nanodiffraction patterns measured at arbitrary overlapping positions at multiple angles about a Bragg peak, eliminating the need for scan registration at different angles. The penetrating nature of x-ray radiation, together with the relaxed constraints of maBPP, will enable in operado imaging of nanowire devices.
PMID: 29345956 [PubMed - as supplied by publisher]
Two-Photon-Excited Silica and Organosilica Nanoparticles for Spatiotemporal Cancer Treatment.
Adv Healthc Mater. 2018 Jan 18;:
Authors: Croissant JG, Zink JI, Raehm L, Durand JO
Coherent two-photon-excited (TPE) therapy in the near-infrared (NIR) provides safer cancer treatments than current therapies lacking spatial and temporal selectivities because it is characterized by a 3D spatial resolution of 1 µm3 and very low scattering. In this review, the principle of TPE and its significance in combination with organosilica nanoparticles (NPs) are introduced and then studies involving the design of pioneering TPE-NIR organosilica nanomaterials are discussed for bioimaging, drug delivery, and photodynamic therapy. Organosilica nanoparticles and their rich and well-established chemistry, tunable composition, porosity, size, and morphology provide ideal platforms for minimal side-effect therapies via TPE-NIR. Mesoporous silica and organosilica nanoparticles endowed with high surface areas can be functionalized to carry hydrophobic and biologically unstable two-photon absorbers for drug delivery and diagnosis. Currently, most light-actuated clinical therapeutic applications with NPs involve photodynamic therapy by singlet oxygen generation, but low photosensitizing efficiencies, tumor resistance, and lack of spatial resolution limit their applicability. On the contrary, higher photosensitizing yields, versatile therapies, and a unique spatial resolution are available with engineered two-photon-sensitive organosilica particles that selectively impact tumors while healthy tissues remain untouched. Patients suffering pathologies such as retinoblastoma, breast, and skin cancers will greatly benefit from TPE-NIR ultrasensitive diagnosis and therapy.
PMID: 29345434 [PubMed - as supplied by publisher]
Mechanistic investigation of visible light driven photocatalytic inactivation of E. coli by Ag-AgCl/ZnFe2O4.
Environ Sci Pollut Res Int. 2018 Jan 17;:
Authors: Upreti AR, Khadgi N, Li Y
In this study, photocatalytic inactivation of Escherichia coli was investigated over magnetic nanocomposite Ag-AgCl/ZnFe2O4. The nanocomposite demonstrated efficient photocatalytic activity by complete inactivation of the bacteria within 60 min of visible light irradiation. The anions HPO42- and SO42- were found to play the most important role in the inhibition of photocatalytic inactivation of E. coli. A systematic investigation of mechanism of photocatalytic bacterial inactivation was carried out based on cell membrane injury test, scanning electron microscopy (SEM) of bacterial morphology changes, Fourier transform infrared (FTIR) spectroscopy of E. coli cells before and after treatment, superoxide dismutase (SOD) and catalase (CAT) activity assay, and role of various reactive oxygen species (ROS). The activities of SOD and CAT enzymes were found to decrease due to the ROSs attacks during photocatalytic inactivation. The ROS produced in the photocatalytic disinfection severely altered the bacterial permeability and led to protein fragmentation, release of ions, and generation of protein carbonyl derivatives. The leaked cytoplasmic substances and cell debris were further degraded and, ultimately, mineralized with prolonged photocatalytic treatment.
PMID: 29344915 [PubMed - as supplied by publisher]
An Endogenous Vaccine Based on Fluorophores and Multivalent Immunoadjuvants Regulates Tumor Micro-Environment for Synergistic Photothermal and Immunotherapy.
Authors: Li L, Yang S, Song L, Zeng Y, He T, Wang N, Yu C, Yin T, Liu L, Wei X, Wu Q, Wei Y, Yang L, Gong C
Recently, near-infrared (NIR) light-based photothermal therapy (PTT) has been widely applied in cancer treatment. However, in most cases, the tissue penetration depth of NIR light is not sufficient and thus photothermal therapy is unable to completely eradicate deep, seated tumors inevitably leading to recurrence of the tumor. Due to this significant limitation of NIR, improved therapeutic strategies are urgently needed. Methods: We developed an endogenous vaccine based on a novel nanoparticle platform for combinatorial photothermal ablation and immunotherapy. The design was based on fluorophore-loaded liposomes (IR-7-lipo) coated with a multivalent immunoadjuvant (HA-CpG). In vitro PTT potency was assessed in cells by LIVE/DEAD and Annexin V-FITC/PI assays. The effect on bone marrow-derived dendritic cells (BMDC) maturation and antigen presentation was evaluated by flow cytometry (FCM) with specific antibodies. After treatment, the immune cell populations in tumor micro-environment and the cytokines in the serum were detected by FCM and Elisa assay, respectively. Finally, the therapeutic outcome was investigated in an animal model. Results: Upon irradiation with 808 nm laser, IR-7-lipo induced tumor cell necrosis and released tumor-associated antigens, while the multivalent immunoadjuvant improved the expression of co-stimulatory molecules on BMDC and promoted antigen presentation. The combination therapy of PTT and immunotherapy regulated the tumor micro-environment, decreased immunosuppression, and potentiated host antitumor immunity. Most significantly, due to an enhanced antitumor immune response, combined photothermal immunotherapy was effective in eradicating tumors in mice and inhibiting tumor metastasis. Conclusion: This endogenous vaccination strategy based on synergistic photothermal and immunotherapy may provide a potentially effective approach for treatment of cancers, especially those difficult to be surgically removed.
PMID: 29344312 [PubMed - in process]
Mesoporous Carbon Nanospheres as a Multifunctional Carrier for Cancer Theranostics.
Authors: Zhou L, Jing Y, Liu Y, Liu Z, Gao D, Chen H, Song W, Wang T, Fang X, Qin W, Yuan Z, Dai S, Qiao ZA, Wu C
Optical nanomaterials with intense absorption in near-infrared (NIR) region hold great promise for biomedical applications such as photothermal therapy (PTT) and photoacoustic imaging (PAI). In this work, we report mesoporous carbon nanospheres (Meso-CNs) with broadband and intense absorption in the UV-Vis-NIR region (300-1400 nm) and explore their potential as a multifunctional platform for photoacoustic imaging and chemo-photothermal therapy. Methods: Meso-CNs were prepared by a "silica-assisted" synthesis strategy and characterized by transmission electron microscope and optical spectroscopy. We investigated the photothermal conversion and photoacoustic imaging of Meso-CNs in comparison with single-walled carbon nanotubes (SWCNTs), graphene and gold nanorods (GNRs). In vitro cellular assays and in vivo chemo-photothermal combination therapy were performed. Results: The absorption coefficients of Meso-CNs are 1.5-2 times higher than those of SWCNTs and graphene and are comparable to those of GNRs in both the first and the second near-infrared optical windows (NIR-I and NIR-II) of tissues. When exposed to an NIR laser, the photothermal and photoacoustic signal generation of Meso-CNs are also stronger than those of SWCNTs, graphene, and GNRs. DOX was loaded into Meso-CNs with a high efficiency (35 wt%) owing to the unique mesoporous structure. Particularly, the drug release from Meso-CNs is sensitive to both pH and NIR light stimulation. In vivo chemo-photothermal combination therapy demonstrates a remarkable inhibition effect on tumor growth under NIR laser treatment. Conclusions: We have developed Meso-CNs for photothermal conversion and photoacoustic imaging. The porous structure also serves as a drug carrier and the drug release can be controlled by pH and external light. The high drug loading capacity, superior photothermal and photoacoustic generation, together with the apparent chemo-photothermal therapeutic effect, make Meso-CNs a promising platform for cancer theranostics.
PMID: 29344297 [PubMed - in process]
Accuracy and Reliability of Infrared Thermography in Assessment of the Breasts of Women Affected by Cancer.
J Med Syst. 2017 May;41(5):87
Authors: de Jesus Guirro RR, Oliveira Lima Leite Vaz MM, das Neves LMS, Dibai-Filho AV, Carrara HHA, de Oliveira Guirro EC
Evaluate reliability and accuracy of infrared thermography in the assessment of women wth breasts cancer. Thirty-five participants had unilateral breast cancer and 17 control subjects were assessed using infrared thermography. To evaluate reliability, two professionals, who were experienced, measured the temperature of the infrared images in two different moments, with a one-week interval. Biopsy was used as a gold standard exam with regard identify breast cancer. The analysis illustrated excellent reliability in terms of the affected, contralateral and control breasts with the intra-class correlation coefficient values ranging from 0.948 to 0.999. Standard measurement error ranged from 0.04 to 0.28 °C, and minimum detectable change deviated from 0.11 to 0.78 °C. Moreover, low to moderate accuracy were observed in terms of the establishment of the breast cancer diagnosis with values of the area under the receiver operating characteristic (ROC) curve ranging from 0.571 and 0.749. Breasts affected by cancer present higher skin temperature compared to contralateral and control. Furthermore, excellent reliability of the analysis of the infrared images and low-moderate accuracy in terms diagnosis were observed. Considering the results, infrared thermography can be applied as an instrument complement the assessment of breast cancer patients, but not for diagnostic purposes.
PMID: 28405947 [PubMed - indexed for MEDLINE]