Graphene-interfaced flexible and stretchable micro-nano electrodes: from fabrication to sweat glucose detection.

Flexible and stretchable wearable electronic devices have received tremendous attention for their non-invasive and personal health monitoring applications. These devices have been fabricated by integrating flexible substrates and graphene nanostructures for non-invasive detection of physiological risk biomarkers from human bodily fluids, such as sweat, and monitoring of human physical motion tracking parameters. The extraordinary properties of graphene nanostructures in fully integrated wearable devices have enabled improved sensitivity, electronic readouts, signal conditioning and communication, energy harvesting from power sources through electrode design and patterning, and graphene surface modification or treatment. This review explores advances made toward the fabrication of graphene-interfaced wearable sensors, flexible and stretchable conductive graphene electrodes, as well as their potential applications in electrochemical sensors and field-effect-transistors (FETs) with special emphasis on monitoring sweat biomarkers, mainly in glucose-sensing applications. The review emphasizes flexible wearable sweat sensors and provides various approaches thus far employed for the fabrication of graphene-enabled conductive and stretchable micro-nano electrodes, such as photolithography, electron-beam evaporation, laser-induced graphene designing, ink printing, chemical-synthesis and graphene surface modification. It further explores existing graphene-interfaced flexible wearable electronic devices utilized for sweat glucose sensing, and their technological potential for non-invasive health monitoring applications.

Semiconductor quantum dots in photoelectrochemical sensors from fabrication to biosensing applications.

Semiconductor quantum dots (QDs) are a promising class of nanomaterials for developing new photoelectrodes and photoelectrochemistry systems for energy storage, transfer, and biosensing applications. These materials have unique electronic and photophysical properties and can be used as optical nanoprobes in displays, biosensors, imaging, optoelectronics, energy storage and energy harvesting. Researchers have recently been exploring the use of QDs in photoelectrochemical (PEC) sensors, which involve exciting a QD-interfaced photoactive material with a flashlight source and generating a photoelectrical current as an output signal. The simple surface properties of QDs also make them suitable for addressing issues related to sensitivity, miniaturization, and cost-effectiveness. This technology has the potential to replace current laboratory practices and equipment, such as spectrophotometers, used for testing sample absorption and emission. Semiconductor QD-based PEC sensors offer simple, fast, and easily miniaturized sensors for analyzing a variety of analytes. This review summarizes the various strategies for interfacing QD nanoarchitectures for PEC sensing, as well as their signal amplification. PEC sensing devices, particularly those used for the detection of disease biomarkers, biomolecules (glucose, dopamine), drugs, and various pathogens, have the potential to revolutionize the biomedical field. This review discusses the advantages of semiconductor QD-based PEC biosensors and their fabrication methods, with a focus on disease diagnostics and the detection of various biomolecules. Finally, the review provides prospects and considerations for QD-based photoelectrochemical sensor systems in terms of their sensitivity, speed, and portability for biomedical applications.

Electrophoretic Fabrication of ZnO/CuO and ZnO/CuO/rGO Heterostructures-based Thin Films as Environmental Benign Flexible Electrode for Supercapacitor.

Sustainable fabrication of flexible hybrid supercapacitor electrodes is extensively investigated during the current era to solve global energy problems. Herein, we used a cost-effective and efficient electrophoretic deposition (EPD) approach to fabricate a hybrid supercapacitor electrode. ZnO/CuO and ZnO/CuO/rGO heterostructure were prepared by sol-gel synthesis route and were electrophoretically deposited on indium tin oxide (ITO) substrate as a thin uniform layer using 1 V for 20 min at 50 mV/s. ZnO/CuO and ZnO/CuO/rGO heterostructure coated ITOs were then employed as the working electrode in a three-electrode setup for supercapacitor measurements. The fabricated electrodes have been investigated by Galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) to study their charge storage properties. ZnO/CuO revealed a specific capacitance of 1945 F g-1 at 2 mV/s and 999 F g-1 at 5 A g-1. However, an increased specific capacitance of 2305 F g-1 was measured for ZnO/CuO/rGO heterostructure at 2 mV/s and 1235 F g-1 at 5 A g-1. The lower internal resistance was observed for ZnO/CuO/rGO heterostructure, indicating good conductivity of the electrode material. Thus, the overall results of the current study suggest that EPD-assisted ZnO/CuO/rGO heterostructure hybrid electrode possess a substantial potential for energy storage as a supercapacitor.

Phyto-synthesized facile Pd/NiOPdO ternary nanocomposite for electrochemical supercapacitor applications.

Sustainable and effective electrochemical materials for supercapacitors are greatly needed for solving the global problems of energy storage. In this regard, a facile nanocomposite of Pd/NiOPdO was synthesized using foliar phyto eco-friendly agents and examined as an electrochemical electrode active material for supercapacitor application. The nanocomposite showed a mixed phase of a ternary nano metal oxide phase of rhombohedral NiO and tetragonal PdO confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and XPS (X-rays photoelectron spectroscopy). The optical (direct) energy value of the synthesized nanocomposite was 3.14 eV. The phyto-functionalized nanocomposite was studied for electrochemical supercapacitor properties and revealed a specific capacitance of 88 F g-1 and low internal resistance of 0.8 Ω. The nanoscale and phyto organic species functionalized nanocomposite exhibited enhanced electrochemical properties for supercapacitor application.

Graphene and carbon nanotubes interfaced electrochemical nanobiosensors for the detection of SARS-CoV-2 (COVID-19) and other respiratory viral infections: A review.

Recent COVID-19 pandemic has claimed millions of lives due to lack of a rapid diagnostic tool. Global scientific community is now making joint efforts on developing rapid and accurate diagnostic tools for early detection of viral infections to preventing future outbreaks. Conventional diagnostic methods for virus detection are expensive and time consuming. There is an immediate requirement for a sensitive, reliable, rapid and easy-to-use Point-of-Care (PoC) diagnostic technology. Electrochemical biosensors have the potential to fulfill these requirements, but they are less sensitive for sensing viruses/viral infections. However, sensitivity and performance of these electrochemical platforms can be improved by integrating carbon nanostructure, such as graphene and carbon nanotubes (CNTs). These nanostructures offer excellent electrical property, biocompatibility, chemical stability, mechanical strength and, large surface area that are most desired in developing PoC diagnostic tools for detecting viral infections with speed, sensitivity, and cost-effectiveness. This review summarizes recent advancements made toward integrating graphene/CNTs nanostructures and their surface modifications useful for developing new generation of electrochemical nanobiosensors for detecting viral infections. The review also provides prospects and considerations for extending the graphene/CNTs based electrochemical transducers into portable and wearable PoC tools that can be useful in preventing future outbreaks and pandemics.

Biosensors for detecting viral and bacterial infections using host biomarkers: a review.

Viral and bacterial infections commonly occur by their transmission through air, contaminated food, water, body fluids or physical contact from person to person. They rapidly spread among the population causing millions of deaths worldwide. One of the major challenges in the diagnosis of infection is differential diagnosis of viral from bacterial infections. Constant viral mutations, reassortment and recombination give rise to the emergence of new and diverse viral populations which makes the diagnosis difficult. Antibiotics prescribed for patients suffering from viral infections are ineffective and a contributing factor to bacterial antibiotic resistance. Evaluating the existing biosensing platforms for early diagnosis of the bacterial etiology of infections enables researchers and clinicians to differentially diagnose viral infections. Over the last decade, many biosensors have been developed to detect a wide range of bacterial and viral markers and reduce the costs for healthcare. There has been considerable interest in finding diagnostic and prognostic biomarkers that can be detected in blood and predict bacterial and viral infections. This review provides an overview on the existing biosensor technology platforms for host biomarker detection that can be applied for differential diagnosis of viral and bacterial infections, as well as recommended considerations and future prospects of viral/bacterial infection detection technology.

Iron oxide nanoparticles based magnetic luminescent quantum dots (MQDs) synthesis and biomedical/biological applications: A review.

Combination of quantum dots (QDs) and magnetic nanoparticles (MNPs) as magnetic quantum dots (MQDs) has a broad range of applications as multifunctional nanoscale devices in biological imaging, medical nano-diagnostics and nanomedicine. MQDs derived from iron oxide nanoparticles and QDs possess excellent superparamagnetic and fluorescent properties, respectively making them multifunctional nanoprobes because of their; (a) strong magnetic strength with tunable functionality, such as rapid and simple magnetic separation, (b) intense and stable fluorescence from QDs combined with tunable biological functionality upon QDs' bio-activation, and (c) imaging/visualization by simple ultraviolet light exposure. These excellent features of MQD nanoprobes enable them to be used for magnetic resonance imaging (MRI) as contrast agents, nano-diagnostic systems for Point-of-Care (PoC) disease diagnosis, theranostics nanorobots and in other bio-medical applications. Most of MQDs are derived from iron based MNPs because of their abundancy, superparamagnetic properties, low cost and easy to synthesize. In this review, we present different methods employed for chemical synthesis of MQDs derived from iron oxide MNPs, their major chemical compositions and important parameters, such as precursor compositions, quantum yield and magnetic properties. The review also summarizes the most frequently used MQDs in applications such as bio-imaging, drug delivery, biosensor platforms and finally ends with future prospects and considerations for MQDs in biomedical applications.

Quercetin in the form of a nano-antioxidant (QTiO2) provides stabilization of quercetin and maximizes its antioxidant capacity in the mouse fibroblast model.

Living cells are constantly exposed to reactive oxygen species (ROS) causing them to rely on a constant supply of exogenous antioxidants. Quercetin (Q) is one of the potent exogenous antioxidants utilized in various antioxidant formulations. However, the potential application of Q is largely limited because of its poor water solubility. In this study, we employed titanium dioxide (TiO2) nanoparticles to maximize cellular penetration and antioxidant effect of Q on mouse fibroblast cells. To accomplish this, polyethylene glycol (PEG) modified TiO2-nanoparticle surfaces were utilized that exhibited better dispersion, with enhanced biocompatibility. Cell viability assays using Q and Q-conjugated TiO2-nanoparticles (QTiO2) were evaluated in terms of cell morphology as well as with an immunoblotting analysis to look for key biomarkers of apoptosis. In addition, cleavages of Cas 3 and PARP were obtained in cells treated with Q. Furthermore, antioxidant defence with QTiO2 was validated by means of the Nrf2 upregulation pathway. We also observed increased expressions of target enzymes; HO-1, NQO1 and SOD1 in QTiO2-treated cells. The antioxidant potency of the QTiO2 nano-antioxidant form was successfully tested in ROS and superoxide radicals induced cells. Our results demonstrated that the QTiO2 nano-antioxidant promoted a high quercetin bioavailability and stability, in cells with maximal antioxidant potency against ROS, with no signs of cytotoxicity.

Role of p53 circuitry in tumorigenesis: A brief review.

Maintenance of genome integrity under the stressed condition is paramount for normal functioning of cells in the multicellular organisms. Cells are programmed to protect their genome through specialized adaptive mechanisms which will help decide their fate under stressed conditions. These mechanisms are the outcome of activation of the intricate circuitries that are regulated by the p53 master protein. In this paper, we provided a comprehensive review on p53, p53 homologues and their isoforms, including a description about the ubiquitin-proteasome system emphasizing its role in p53 regulation. p53 induced E3(Ub)-ligases are an integral part of the ubiquitin-proteasome system. This review outlines the roles of important E3(Ub)-ligases and their splice variants in maintaining cellular p53 protein homeostasis. It also covers up-to-date and relevant information on small molecule Mdm2 inhibitors originated from different organizations. The review ends with a discussion on future prospects and investigation directives for the development of next-generation modulators as p53 therapeutics.

Revealing the molecular interactions of aptamers that specifically bind to the extracellular domain of HER2 cancer biomarker protein: An in silico assessment.

Single-stranded (ss) oligonucleotide aptamers are emerging as the promising substitutes for monoclonal antibodies because of their low production cost and good batch-to-batch consistency. Aptamers vividly bind to a variety of cellular targets and alter their functions with a remarkable degree of specificities. In this study, the positive clones of human epidermal growth factor receptor 2 (HER2) specific binding ssDNA aptamers which were previously identified by in vitro Systematic Evolution of Ligands by EXponential enrichment (SELEX) process, hitherto lacking the putative binding site information and residues crucial for aptamer recognition are studied. Primarily, four putative DNA binding regions present on the HER2 extracellular domain (ECD) were identified using prediction servers and electrostatic potential maps, which were further exploited to delineate the aptamer binding features. Molecular docking and molecular dynamics (MD) simulations revealed stable binding nature of three aptamers (H2>H1>H6), which chose Site 2a as preferred binding site present on the HER2(ECD) protein. Furthermore, amino acid residues viz. Asn37, Gln59, Arg81-Gln84, Asp88, and Lys128 of Site 2a were found to be crucial for high-affinity binding. This knowledge can be utilized as a benchmark for the future studies, in search for better and highly specific anti-HER2 aptamers as cancer therapeutics or as diagnostic agents.

A Hand-Held Point-of-Care Biosensor Device for Detection of Multiple Cancer and Cardiac Disease Biomarkers Using Interdigitated Capacitive Arrays.

This paper presents a hand-held point-of-care device that incorporates a lab-on-a-chip module with interdigitated capacitive biosensors for label-free detection of multiple cancer and cardiovascular disease biomarkers. The developed prototype is comprised of a cartridge incorporating capacitive biodetection sensors, a sensitive capacitive readout electronics enclosed in a hand-held unit, and data analysis software calculating the concentration of biomarkers using previously stored reference database. The capacitive biodetection sensors are made of interdigitated circular electrodes, which are preactivated with single (for detecting one biomarker) or multiple specific antibodies (for detecting multiple disease biomarkers). Detection principle of capacitive biosensor is based on measuring the level of capacitance change between interdigitated electrode pairs induced by the change in dielectric constant due to affinity-based electron exchange in between antibodies/antigens and electrodes. The more antibody-antigens binding occurs, the more capacitance change is measured due to the change in dielectric constant of the capacitance media. The device uses preactivated ready-to-use cartridges embedded with capacitive biosensors with shelf-life of three months under optimal conditions, and is capable of onsite diagnosis and can report the result in less than 30 min. The device is verified with real patient blood samples for six different disease biomarkers.

Graphene-interfaced electrical biosensor for label-free and sensitive detection of foodborne pathogenic E. coli O157:H7.

E. coli O157:H7 is an enterohemorrhagic bacteria responsible for serious foodborne outbreaks that causes diarrhoea, fever and vomiting in humans. Recent foodborne E. coli outbreaks has left a serious concern to public health. Therefore, there is an increasing demand for a simple, rapid and sensitive method for pathogen detection in contaminated foods. In this study, we developed a label-free electrical biosensor interfaced with graphene for sensitive detection of pathogenic bacteria. This biosensor was fabricated by interfacing graphene with interdigitated microelectrodes of capacitors that were biofunctionalized with E. coli O157:H7 specific antibodies for sensitive pathogenic bacteria detection. Here, graphene nanostructures on the sensor surface provided superior chemical properties such as high carrier mobility and biocompatibility with antibodies and bacteria. The sensors transduced the signal based on changes in dielectric properties (capacitance) through (i) polarization of captured cell-surface charges, (ii) cells' internal bioactivity, (iii) cell-wall's electronegativity or dipole moment and their relaxation and (iv) charge carrier mobility of graphene that modulated the electrical properties once the pathogenic E. coli O157:H7 captured on the sensor surface. Sensitive capacitance changes thus observed with graphene based capacitors were specific to E. coli O157:H7 strain with a sensitivity as low as 10-100 cells/ml. The proposed graphene based electrical biosensor provided advantages of speed, sensitivity, specificity and in-situ bacterial detection with no chemical mediators, represents a versatile approach for detection of a wide variety of other pathogens.

Toxicity evaluation of e-juice and its soluble aerosols generated by electronic cigarettes using recombinant bioluminescent bacteria responsive to specific cellular damages.

Electronic-cigarettes (e-cigarette) are widely used as an alternative to traditional cigarettes but their safety is not well established. Herein, we demonstrate and validate an analytical method to discriminate the deleterious effects of e-cigarette refills (e-juice) and soluble e-juice aerosol (SEA) by employing stress-specific bioluminescent recombinant bacterial cells (RBCs) as whole-cell biosensors. These RBCs carry luxCDABE-operon tightly controlled by promoters that specifically induced to DNA damage (recA), superoxide radicals (sodA), heavy metals (copA) and membrane damage (oprF). The responses of the RBCs following exposure to various concentrations of e-juice/SEA was recorded in real-time that showed dose-dependent stress specific-responses against both the e-juice and vaporized e-juice aerosols produced by the e-cigarette. We also established that high doses of e-juice (4-folds diluted) lead to cell death by repressing the cellular machinery responsible for repairing DNA-damage, superoxide toxicity, ion homeostasis and membrane damage. SEA also caused the cellular damages but the cells showed enhanced bioluminescence expression without significant growth inhibition, indicating that the cells activated their global defense system to repair these damages. DNA fragmentation assay also revealed the disintegration of total cellular DNA at sub-toxic doses of e-juice. Despite their state of matter, the e-juice and its aerosols induce cytotoxicity and alter normal cellular functions, respectively that raises concerns on use of e-cigarettes as alternative to traditional cigarette. The ability of RBCs in detecting both harmful effects and toxicity mechanisms provided a fundamental understanding of biological response to e-juice and aerosols.

Nanomaterial resistant microorganism mediated reduction of graphene oxide.

In this study, soil bacteria were isolated from nanomaterials (NMs) contaminated pond soil and enriched in the presence of graphene oxide (GO) in mineral medium to obtain NMs resistant bacteria. The isolated resistant bacteria were biochemically and genetically identified as Fontibacillus aquaticus. The resistant bacteria were allowed to interact with engineered GO in order to study the biotransformation in GO structure. Raman spectra of GO extracted from culture medium revealed decreased intensity ratio of ID/IG with subsequent reduction of CO which was consistent with Fourier transform infrared (FTIR) results. The structural changes and exfoliatied GO nanosheets were also evident from transmission electron microscopy (TEM) images. Ultraviolet-visible spectroscopy, high resolution X-ray diffraction (XRD) and current-voltage measurements confirmed the reduction of GO after the interaction with resistant bacteria. X-ray photoelectron spectroscopy (XPS) analysis of biotransformed GO revealed reduction of oxygen-containing species on the surface of nanosheets. Our results demonstrated that the presented method is an environment friendly, cost effective, simple and based on green approaches for the reduction of GO using NMs resistant bacteria.

Determining the fate of fluorescent quantum dots on surface of engineered budding S. cerevisiae cell molecular landscape.

In this study, we surface engineered living S. cerevisiae cells by decorating quantum dots (QDs) and traced the fate of QDs on molecular landscape of single mother cell through several generation times (progeny cells). The fate of QDs on cell-surface was tracked through the cellular division events using confocal microscopy and fluorescence emission profiles. The extent of cell-surface QDs distribution among the offspring was determined as the mother cell divides into daughter cells. Fluorescence emission from QDs on progeny cells was persistent through the second-generation time (~240min) until all of the progeny cells lost their cell-bound QDs during the third generation time (~360min). The surface engineered yeast cells were unaffected by the QDs present on their molecular landscapes and retained their normal cellular growth, architecture and metabolic activities as confirmed by their viability, scanning electron microscopy (SEM) examinations and cytotoxicity tests, respectively. Our results demonstrated that QDs on mother cell landscape tend to distribute among its progeny cells that accompanied with concomitant reduction in QDs' fluorescence, which can be quantified. We suggest that surface engineered cells with QDs will enable investigating the cellular behavior and monitoring cell growth patterns as nanobiosensors for screening of drugs/chemicals at single cell level with fewer side effects.

Whole-cell based label-free capacitive biosensor for rapid nanosize-dependent toxicity detection.

Despite intensive studies on examining the toxicity of nanomaterials (NMs), our current understanding on potential toxicity in relation to size and cellular responses has remained limited. In this work, we have developed a whole-cell based capacitive biosensor (WCB) to determine the biological toxicity of nanoparticles (NPs) using iron oxide (Fe3O4) NPs as models. This WCB chip comprised of an array of capacitor sensors made of gold interdigitated microelectrodes on which living Escherichia coli cells were immobilized. Cells-on-chip was then allowed to interact with different sizes of Fe3O4 NPs (5, 20 and 100 nm) and concentration-depended cellular-responses were measured in terms of change in dielectric properties (capacitance) as a function of applied AC frequency. The WCB response showed smaller-sized Fe3O4 NPs (5 nm) induced maximum change in surface capacitance because of their effective cellular interaction with E. coli cells-on-chip indicating that the cells suffered from severe cellular deformation, which was confirmed by scanning electron microscopic (SEM) examination. Further our results were validated through their cell viability and E. coli responses at the interface of cell-membrane and NPs as a proof-of-concept. WCB response showed a size-dependent shift in maximum response level from 2 µg/ml of 5 nm sized NPs to 4 µg/ml with NP-sizes greater than 20 nm. The developed WCB offered real-time, label-free and noninvasive detection of cellular responses against Fe3O4 NPs' toxicity with speed, simplicity and sensitivity that can be extended to toxicity screening of various other NPs.

In vitro HER2 protein-induced affinity dissociation of carbon nanotube-wrapped anti-HER2 aptamers for HER2 protein detection.

A new in vitro assay was developed to detect human epidermal growth factor receptor 2 (HER2) protein, based on affinity dissociation of carbon nanotube (CNT)-wrapped anti-HER2 ssDNA aptamers. First, we selected an anti-HER2 ssDNA aptamer (H2) using an in vitro serial evolution of ligands by an exponential enrichment (SELEX) process. Then the fluorescently labelled H2 ssDNAs were tightly packed on CNTs that had previously been coupled with magnetic microbeads (MBs), forming MB-CNT-H2 hybrids. The loading capacity of these MB-CNTs heterostructures (2.8 × 10(8)) was determined to be 0.025 to 3.125 µM of H2. HER2 protein-induced H2 dissociation occurred from MB-CNT-H2 hybrids, which was specifically induced by the target HER2 protein, with a dissociation constant (Kd) of 270 nM. The stoichiometric affinity dissociation ratio with respect to H2-to-HER2 protein was shown to be approximately 1 : 1. Our results demonstrated that the developed assay can be an effective approach in detecting native forms of disease biomarkers in free solutions or in biological samples, for accurate diagnosis.

Quantum dot conjugated S. cerevisiae as smart nanotoxicity indicators for screening the toxicity of nanomaterials.

In this study, we have evaluated the toxicity of different forms of carbon nanotubes (CNTs) using S. cerevisiae-QD (SQD) bioconjugates as a novel fluorescent biological nanotoxicity indicator. A CNT mediated effect in SQD bioconjugates was used as an indicator for the changes occurring at the cell-membrane interfaces that induced disruption of membrane bound QDs resulting in the loss of fluorescence. Single, double and multiwalled carbon nanotubes (SWCNTs, DWCNTs and MWCNTs) were tested for their toxicities imposed on SQD bioconjugates. Bioconjugates exposed to varying concentrations of different forms of CNTs exhibited different modes of toxicities on SQD bioconjugates. SQD bioconjugates were highly responsive in the 0.1-10 µg mL-1 CNT concentration range after 1 h of exposure. The toxicity of CNTs was linked to the number of CNT walls. These results were further confirmed by SEM analysis and cell-viability tests that were consistent with the toxicity assays using fluorescent bioconjugates with different types of CNTs. SWCNTs imposed more severe cellular toxicity followed by MWCNTs and DWCNTs and the order of increasing cellular-damage by CNTs followed DWCNTs < MWCNTs < SWCNTs. This study speculates that the cell-injury by CNTs depends on their physical properties, such as layers of walls, non-covalent forces and dispersion states. Our results demonstrated a facile optical strategy that enables rapid and real-time cytotoxicity screening with yeast as model living-cells for engineering nanomaterials.

Outcome of unilateral lateral rectus recession and medial rectus resection in primary exotropia.

BACKGROUND: The purpose of this study was to measure the success rate of unilateral lateral rectus recession and medial rectus resection in primary exotropia. METHODS: This is an interventional case series of 55 patients with primary exotropia (degree of deviation 15-85 PD), above the age of 5 years. Patients were treated in the Department of Ophthalmology, Jinnah Postgraduate Medical Center, Karachi, Pakistan, during the period of July 2009 to March 2010. All the patients underwent surgical procedure i.e., lateral rectus muscle recession (maximum up to 10 mm) and medial rectus muscle resection (up to 6 mm) of one eye, according to the Park's method. Surgery was done based on prism cover test measurements obtained at 6 m with appropriate optical correction in place. Patients were re evaluated at one day, one month, two months and six months post operatively. Final outcome was considered at the end of six months at which achievement of ≤10 PD of exotropia was the success. Data was analyzed on SPSS version 17.0. RESULTS: We obtained success (≤10 PD) in 42 out of 55 patients (76.4%) and 13 out of 55 patients (23.6%) did not meet our criteria for surgical success (>10 PD). Analysis of success with the type of primary exotropia showed that success was achieved in 22 out of 24 cases of intermittent type (91.6%) and 20 out of 31 cases of constant type (64.5%)(P Value 0.019). The highest percentage of success was achieved in patients with the pre-operative deviation of ≤70 PD i.e., 93.3% (42 out of 45 cases), while none of the patients with the pre-operative deviation of >70 PD (10 out of 10 cases) achieved the criteria for success. CONCLUSION: We conclude that pre-operative deviation is one of the strongest predictor for favorable surgical outcome. Therefore, eliminating the factors causing error in the correct determination of pre-operative deviation should improve the success and predictability of the surgical outcome. Despite the obstacles in the surgical management of strabismus, our results are encouraging.

Carbon nanotube decorated magnetic microspheres as an affinity matrix for biomolecules.

Carbon nanotube (CNT) decorated magnetic microspheres were fabricated to develop a multimodal platform that utilizes non-covalent molecular interactions of CNTs to magnetically separate biomolecules. Hybrid CNT-microspheres prepared by a feasible method reported herein had a well-defined structure as characterized by Raman spectroscopy and scanning electron microscopy. Binding interactions of resulting magnetic CNT-microspheres with DNA oligonucleotides were studied to demonstrate that single stranded DNA (ssDNA) in a solution can be effectively recovered by magnetic CNT-microspheres through strong physical wrapping of DNA around CNTs' walls. The magnetic character of these CNT-microspheres combined with their capability to bind other molecules including DNA allows their use as an affinity matrix that can be utilized in affinity separation of biomolecules, and also as a platform to monitor non-covalent binding interactions of CNTs with other biomolecules. As a proof of concept, we report on the use of these CNT-microspheres in in vitro selection of ssDNA aptamers against carcinoembryonic antigen (CEA), a cancer biomarker, by Systematic Evolution of Ligands by Exponential Enrichment (SELEX). ssDNA aptamer candidates that have strong affinity towards CEA were successfully separated magnetically from a pool of ssDNA (∼1014 molecules). Our results demonstrate that CNT-microspheres can serve as strong tools for affinity separation methodologies and can be utilized for various affinity pairs in solution.