Intrascleral Fixation of Flanged Polypropylene Suture(s) for Iridodialysis Repair.

PURPOSE: We will describe a minimally invasive technique for the repair of iridodialysis, without conjunctival dissections, using intrasceral fixation of a 6-0 polypropylene suture with a flanged tip. METHODS: A flange was created at the end of the suture with thermoplasticity. An ab interno passing of the needle attached to the suture was performed through the peripheral part of the iris and was further passed out from the eye 1.5 mm to 2 mm behind the limbus. Intrascleral fixation of the exterior suture was performed with the aid of the attached needle. After adjusting the tension of the iris relocation, the externalized end of the suture was cut flush to the sclera with scissors. For a wide dialysis, the same manipulations were repeated until the repair was completed. RESULTS: The technique was used in three eyes of three patients. No visual impairments of monocular diplopia and glare were observed after surgery. Postoperatively, the irises remained well positioned, with no suture erosion, suture loosening, hypotony, scleral atrophy, or chronic inflammation being observed within the follow-up period. Mild postoperative hyphema was observed in one eye of blunt trauma. CONCLUSION: The present technique provides minimal surgical invasion for the repair of iridodialysis without creations of scleral flap/groove/pocket and conjunctival dissection.

Myopic Laser Corneal Refractive Surgery Reduces Interdevice Agreement in the Measurement of Anterior Corneal Curvature.

OBJECTIVES: To investigate interdevice differences and agreement in the measurement of anterior corneal curvature obtained by different technologies after laser corneal refractive surgery. METHODS: The prospective study comprised 109 eyes of 109 consecutive patients who had undergone laser-assisted in situ keratomileusis (LASIK). Preoperative and postoperative corneal parameters were measured by Scheimpflug imaging (Pentacam), Placido-slit-scanning (Orbscan) and auto-keratometry (IOLMaster). Preoperative and postoperative anterior corneal curvatures (K readings) were compared between devices. Interdevice agreement was evaluated by Bland-Altman analysis. RESULTS: Preoperatively, the difference of K reading for Pentacam-IOLMaster (0.04±0.20 D) was not statistically significant (P=0.059). The differences between Pentacam-Orbscan and Orbscan-IOLMaster were 0.20±0.34 D (P<0.001) and -0.17±0.29 D (P<0.001), respectively. After surgery, no difference was found for Pentacam-Orbscan (-0.05±0.38, P=0.136). The differences between Pentacam-IOLMaster and Orbscan-IOLMaster were 0.13±0.29 D (P<0.001) and 0.19±0.34 D (P<0.001). Preoperative interdevice agreement (95% limit of agreement [LOA]) between Pentacam and Orbscan, Pentacam and IOLMaster, and Orbscan and IOLMaster were 1.31 D, 0.79 D and 1.14 D, respectively. The 95% LOAs decreased to 1.47 D, 1.14 D, and 1.34 D after refractive surgery. CONCLUSION: Corneal refractive surgery changed the preoperative and postoperative interdevice differences in corneal curvature measurements and reduced interdevice agreement, indicating that the devices are not interchangeable.

Mathematical Method for Analysis of the Refractive Outcome after Toric Intraocular Lens Implantation.

PURPOSE: We aimed to develop a self-designed software programmed with a mathematical method that analyzes the refractive outcome after toric intraocular lens (IOL) implantation, taking the axis misalignment of the toric IOL into consideration. METHODS: A mathematical method that can analyze the refractive outcome after toric IOL implantation was devised. Compared with the conventional method, which performs the analysis based on precise alignment of the IOL, optional meridian orientations of the toric IOL were taken into account in this method. Self-designed computer software was developed using the mathematical method. RESULTS: Relatively high accordance was achieved between the mathematical analysis and the actual postoperative outcome. The mean predicted spherical power was 0.37 ± 0.74 dpt, and the mean measured spherical power was 0.37 ± 0.71 dpt (paired t test, p = 0.98). The mean predicted cylindrical power was -1.35 ± 0.86 dpt, and the mean measured cylindrical power was -1.42 ± 0.85 dpt (p = 0.27). The mean predicted change in the astigmatic axis was 33.7 ± 11.8°, and the mean measured parameter was 32.5 ± 15.4° (p = 0.49). CONCLUSIONS: The advantage of the present mathematical method is that the postoperative refractive outcome can be analyzed under IOL misalignment.

A novel nanoprobe based on single-walled carbon nanotubes/photosensitizer for cancer cell imaging and therapy.

Nanomedicine and nanotechnology have provided an effective platform for integration of therapeutic and diagnostic agents. Single-walled carbon nanotubes (SWCNTs), a highly effective means of transporting cargos of various sizes and types across the cell membrane, are gradually playing a bigger and more important role in the field of nanomedicine. In this study, a novel nanoprobe based on SWCNTs and a fluorescent photosensitizer pyropheophorbide a (PPa), was developed and was used for cancer cell imaging and therapy in vitro. Phospholipids bearing polyehylene-glycol modified SWCNTs that can provide an interface for the conjugation of PPa were prepared by ultrasonication. The polyehylene-glycol modified SWCNTs were then conjugated with PPa by using covalent functionalization method to construct SWCNT-PEG-PPa nanoprobe. The functionalization of SWCNTs was evidenced by UV-vis absorption spectra and fluorescence spectra. Imaging of cancer cells with SWCNT-PEG-PPa nanoprobe was confirmed using two cancer cell lines via laser scanning confocal microscope tests, and killing of cancer cells with SWCNT-PEG-PPa was demonstrated using cytotoxicity tests. Moreover, the stability of SWCNT-PEG-PPa was further investigated. Our experiments indicated that the resulting SWCNT-PEG-PPa nanoprobe should have a great potential to be a potent candidate for cancer imaging and therapy.

Amperometric acetylcholine biosensor based on self-assembly of gold nanoparticles and acetylcholinesterase on the sol-gel/multi-walled carbon nanotubes/choline oxidase composite-modified platinum electrode.

A novel acetylcholinesterase (AChE)/choline oxidase (ChOx) bienzyme amperometric acetylcholine biosensor based on gold nanoparticles (AuNPs) and multi-walled carbon nanotubes (MWCNTs) has been successfully developed by self-assembly process in combination of sol-gel technique. A thiolated aqueous silica sol containing MWCNTs and ChOx was first dropped on the surface of a cleaned Pt electrode, and then AuNPs were assembled with the thiolated sol-gel network. Finally, the alternate deposition of poly (diallyldimethylammonium chloride) (PDDA) and AChE was repeated to assemble different layers of PDDA-AChE on the electrode for optimizing AChE loading. Among the resulting biosensors, the biosensor based on two layers of PDDA-AChE multilayer films showed the best performance. It exhibited a wide linear range, high sensitivity and fast amperometric response, which were 0.005-0.4mM, 3.395 µA/mM, and within 15s, respectively. The biosensor showed long-term stability and acceptable reproducibility. More importantly, this study could provide a simple and effective multienzyme immobilization platform for meeting the demand of the effective immobilization enzyme on the electrode surface.

Thermoacoustic molecular tomography with magnetic nanoparticle contrast agents for targeted tumor detection.

PURPOSE: The primary feasibility steps of demonstrating the ability of microwave-induced thermoacoustic (TA) in phantoms have been previously reported. However, none were shown to target a diseased site in living subjects in thermoacoustic tomography (TAT) field so far. To determine the expressions of oncogenic surface molecules, it is quite necessary to image tumor lesions and acquire pathogenic status on them via TAT. METHODS: Compared to biological tissues, iron oxide nanoparticles have a much higher microwave absorbance. Fe3O4/polyaniline (PANI) nanoparticles were prepared via polymerization of aniline in the Fe304 superparamagnetic fluids. Then Fe3O4/PANI was conjugated to folic acid (FA), which can bind specifically to the surface of the folate receptor used as a tumor marker. FA-Fe3O4/PANI targeted tumor was irradiated by pulsed microwave at 6 GHz for thermoacoustic detection and imaging. RESULTS: The effect of the Fe3O4/PANI superparamagnetic nanoparticles for enhancing TAT images was successfully investigated in ex vivo human blood and in vivo mouse tail. Intravenous administration of the targeted nanoparticles to mice bearing tumors showed fivefold greater thermoacoustic signal and much longer elimination time than that of mice injected with nontargeted nanoparticles in the tumor. The specific targeting ability of FA-Fe3O4/PANI to tumor was also verified on fluorescence microscopy. CONCLUSIONS: Fabricated iron oxide nanoparticles conjugated with tumor ligands for targeted TAT tumor detection at the molecular level was reported for the first time. The results indicate that thermoacoustic molecular imaging with functionalized iron oxide nanoparticles may contribute to targeted and functional early cancer imaging. Also, the modified iron oxide nanoparticles combined with suitable tumor markers may also be used as novel nanomaterials for targeted and guided cancer thermal therapy.

New insights of transmembranal mechanism and subcellular localization of noncovalently modified single-walled carbon nanotubes.

Translocation and localization of single-walled carbon nanotubes (SWNTs) in normal and cancerous cells have significant biomedical implications. In this study, SWNTs functionalized with different biomolecules in cells were observed with confocal laser scanning microscopy. Functionalized with PL-PEG, SWNTs were found to localize exclusively in mitochondria of both tumor and normal cells due to mitochondrial transmembrane potential, but they were found mainly in lysosomes of macrophages due to phagocytosis. However, when conjugated with different molecules, the subcellular localization of the surface-modified SWNT-PL-PEG depended on how SWNTs enter the cells: inside mitochondria if crossing cell membrane or inside lysosomes if being endocytosized. We also show that mitochondrial SWNT-PL-PEG, when irradiated with a near-infrared light, can induce cell apoptosis due to mitochondrial damages. These findings provide a better mechanistic understanding of cellular localization of SWNTs, which could lead to advanced biomedical applications such as the design of molecular transporters and development of SWNT-assisted cancer therapies.

Functional single-walled carbon nanotubes based on an integrin alpha v beta 3 monoclonal antibody for highly efficient cancer cell targeting.

The application of single-walled carbon nanotubes (SWNTs) in the field of biomedicine is becoming an entirely new and exciting topic. In this study, a novel functional SWNT based on an integrin alpha(v)beta(3) monoclonal antibody was developed and was used for cancer cell targeting in vitro. SWNTs were first modified by phospholipid-bearing polyethylene glycol (PL-PEG). The PL-PEG functionalized SWNTs were then conjugated with protein A. A SWNT-integrin alpha(v)beta(3) monoclonal antibody system (SWNT-PEG-mAb) was thus constructed by conjugating protein A with the fluorescein labeled integrin alpha(v)beta(3) monoclonal antibody. In vitro study revealed that SWNT-PEG-mAb presented a high targeting efficiency on integrin alpha(v)beta(3)-positive U87MG cells with low cellular toxicity, while for integrin alpha(v)beta(3)-negative MCF-7 cells, the system had a low targeting efficiency, indicating that the high targeting to U87MG cells was due to the specific integrin targeting of the monoclonal antibody. In conclusion, SWNT-PEG-mAb developed in this research is a potential candidate for cancer imaging and drug delivery in cancer targeting therapy.

Photoacoustic molecular imaging with antibody-functionalized single-walled carbon nanotubes for early diagnosis of tumor.

Single-walled carbon nanotubes (SWNT) in a poly(ethylene)ghycol solution are a biocompatible transporters with strong optical absorption in the near-infrared region, in which the biological tissue is almost transparent with very low absorbance. Here, antibody-functionalized SWNTs for tumor early detection with photoacoustic molecular imaging in vivo are reported. To lay the groundwork for this goal and insure system stability, images were collected in tissue simulating phantoms to determine appropriate detectable concentrations of SWNTs. Preliminary in vitro and in vivo results showed that a high contrast and a high efficient targeting of integrin alpha(v)beta(3) positive U87 human glioblastoma tumours in mice could be achieved. The nontoxicity of functionalized SWNTs has also been demonstrated in our experiment; this feature ensures that SWNTs can be used for clinical applications. This study suggests that photoacoustic molecular imaging with antibody-functionalized SWNTs has the potential to be an effective early tumor diagnosis method.

Cancer photothermal therapy in the near-infrared region by using single-walled carbon nanotubes.

Single-walled carbon nanotubes (SWNTs) have a high optical absorbance in the near-infrared (NIR) region. In this special optical window, biological systems are known to be highly transparent. The optical properties of SWNTs provide an opportunity for selective photothermal therapy for cancer treatment. Specifically, CoMoCAT nanotubes with a uniform size (about 0.81 nm) and a narrow absorption peak at 980 nm are ideal candidates for such a novel approach. Here, CoMoCAT SWNTs are conjugated to folate, which can bind specifically to the surface of the folate receptor tumor markers. Folate-SWNT (FA-SWNT) targeted tumor cells were irradiated by a 980-nm laser. In our in vitro and in vivo experiments, FA-SWNT effectively enhanced the photothermal destruction on tumor cells and noticeably spared the photothermal destruction for nontargeted normal cells. Thus, SWNTs, combined with suitable tumor markers, can be used as novel nanomaterials for selective photothermal therapy for cancer treatment.