Arif Cetin | Boston University (original) (raw)

Papers by Arif Cetin

Turkish Journal of Pharmaceutical Sciences

Objectives: Linagliptin (Lin) is a drug used in treatment of type 2 diabetes mellitus. In this st... more Objectives: Linagliptin (Lin) is a drug used in treatment of type 2 diabetes mellitus. In this study, the electrochemical detection of Lin and its interaction with DNA was analyzed for the first time using voltammetric methods by measuring the oxidation currents of the adenine bases of DNA before and after the interaction. In addition, the electrochemical properties of the Lin were studied. Materials and Methods: The interaction between Lin and DNA was evaluated using differential pulse voltammetry. A three-electrode system comprising of a pencil graphite electrode as the working electrode, reference electrode (Ag/AgCl), and platinum wire as the auxiliary electrode was used in the electrochemical studies. Experimental conditions, such as the concentration, pH of the supporting electrolyte, and immobilization time were optimized to obtain maximum analytical signals. Results: The adenine bases of DNA were evaluated as an analytical signal obtained at approximately +1.2 V vs. Ag/AgCl. After the Lin-DNA interaction, the oxidation currents of adenine decreased as proof of interaction. No reports have been published on Lin interacting with DNA. Based on our results, a diffusion-controlled irreversible redox process involving independent oxidation was revealed for Lin. Under optimum conditions, the detection limit was 6.7 μg/mL for DNA and 21.5 μg/mL for Lin. Based on the observations, Lin has a toxic effect on DNA. Conclusion: We successfully demonstrated that Lin interacts with DNA, and its influence on DNA could play a vital role in the medical effect of the drug.

ACS Applied Materials & Interfaces

Efficient transduction of optical energy to bioelectrical stimuli is an important goal for effect... more Efficient transduction of optical energy to bioelectrical stimuli is an important goal for effective communication with biological systems. For that, plasmonics has a significant potential via boosting the light−matter interactions. However, plasmonics has been primarily used for heat-induced cell stimulation due to membrane capacitance change (i.e., optocapacitance). Instead, here, we demonstrate that plasmonic coupling to photocapacitor biointerfaces improves safe and efficacious neuromodulating displacement charges for an average of 185% in the entire visible spectrum while maintaining the faradic currents below 1%. Hotelectron injection dominantly leads the enhancement of displacement current in the blue spectral window, and the nanoantenna effect is mainly responsible for the improvement in the red spectral region. The plasmonic photocapacitor facilitates wireless modulation of single cells at three orders of magnitude below the maximum retinal intensity levels, corresponding to one of the most sensitive optoelectronic neural interfaces. This study introduces a new way of using plasmonics for safe and effective photostimulation of neurons and paves the way toward ultrasensitive plasmon-assisted neurostimulation devices.

$Research paper thumbnail of Plasmonic Diffraction Field Pattern Imaging Could Resolve Ultra-Sensitive Bio-Information$

ACS Photonics

Subwavelength nanohole arrays have been very attractive for label-free biosensing applications, a... more Subwavelength nanohole arrays have been very attractive for label-free biosensing applications, as they offer simplicity and flexibility in the read-out scheme. Recently, platforms employing imaging-based devices integrated to custom-made light sources and plasmonic nanohole array substrates have been proposed as strong candidates to increase throughput by allowing simultaneous evaluation of binding interactions. Despite their high-throughput and multiplexed nature, these platforms dramatically suffer from sensitivity compared to classical spectrometer-based systems. In this Letter, we introduced a highly sensitive and plasmonic imaging-based platform that can work with very low analyte concentrations. The system employs a tunable optic filter integrated to a CMOS camera that records diffraction intensity patterns of the transmitted light from a plasmonic biochip composed of periodic nanohole arrays. Monitoring diffraction field intensity variations that correspond to transmission values at different wave...

Advanced Engineering Materials

In this article, a wide-band and polarization-insensitive perfect absorber composed of 4 sandwich... more In this article, a wide-band and polarization-insensitive perfect absorber composed of 4 sandwiched layers of dielectric and metal disks is introduced. Compared to classical perfect absorbers, the system supports near-unity absorption within a wider spectral window through multiple perfect absorption mechanisms that exist due to a constituting inter-metal disk, functioning either as a dipolar antenna or a conducting ground for different perfect absorption mechanisms. Circular shape of the antenna makes the working mechanism of the system polarization insensitive. The working principle of the system is investigated through nearand far-field calculations by finite difference time domain (FDTD) simulations. A fine-tuning mechanism of the wide-range perfect absorption window is introduced through geometrical device parameters. The multilayer perfect absorber system is fabricated through a high-quality fabrication method based on electron beam lithography, lift-off method, and multi-step deposition of metal and dielectric layers. The spectral behavior of the perfect absorber system is finally experimentally investigated through Fourier transform infrared (FTIR) spectroscopy.

Biosensors and Bioelectronics

TURKISH JOURNAL OF PHYSICS

We investigated the dispersion relation of surface plasmons (SPs) excited in a medium comprised o... more We investigated the dispersion relation of surface plasmons (SPs) excited in a medium comprised of a left-handed material (LHM) layer. We investigated different light polarizations in SP excitation along an LHM-metal interface. We studied SP excitation through a classical Kretschmann geometry, employing an LHM interlayer between a dielectric and a metal layer. Using this three-layer configuration, we investigated the effect of LHM medium on characterizing SP propagation length, which is directly related to the energy of the surface waves.

Advanced Optical Materials

The test results and diagnostic information can be analyzed by the medical professionals from rem... more The test results and diagnostic information can be analyzed by the medical professionals from remote locations, improving the connectivity of central hubs to the public venues. Numerous scientific discoveries have been made in advanced settings and wellequipped laboratories. The necessity and complexity of these environments limit access to research equipment worldwide. Thus, decentralization of research laboratories has become an alternative solution to improve access to experimentation in field conditions. For instance, a paper origami microscope [6] that fit into a palm of a student made a powerful investigation tool for environment and materials. A detailed analysis of sound recordings by smartphones enabled identification of distinct mosquitoes. [7] These fielddeployable devices and platforms have stimulated emergence of citizen scientists, a population that collectively performs scientific inquiries in public settings. Rich biomolecular measurements from field-portable devices improve the quality of results in terms of accuracy and depth. Monitoring multiple blood markers has enabled diagnostic precision and thorough scientific investigation of blood constituent in patients. Therefore, field-deployable devices should ideally have multiplexed detection of target specimens. Design of such multiplexed detection technologies requires decent complexity at low cost for wide-scale adoptability. In this article, we provide an overview of field-compatible devices with high parameter analysis capabilities for both health monitoring purposes and scientifically enlightening Global health issues are increasingly becoming critical with high fatality rate due to chronic and infectious diseases. Emerging technologies aim to address these problems by understanding the causes of lethal conditions and diagnosing symptoms at early stage. Existing commercial diagnostics primarily focus on single-plex assays due to ease-of-use, simplicity in analysis, and amenability to mass manufacturing. Many research grade devices have utilized only a few molecular and morphological signatures in bodily fluids. However, multiplex devices can improve accuracy, sensitivity, and scalability of research and diagnostic devices. This review presents multiplex assays that utilize optical, electrical, and chemical methods and materials that have the potential to improve portable point-of-care diagnostics. The critical role of emerging optical and complementary assays with multiple contrast mechanisms is investigated to enable highly multiplex analysis in field settings. Multiparameter portable devices for field applications toward health monitoring, food testing, air quality monitoring, and microanalysis in other extreme conditions are examined. Current trends indicate the need for validation of health diagnosis based on a large number of biomarkers in randomized clinical trials. Advanced digital analysis, crowdsourced solutions, and robust user interfaces will become an integral part of the connected global health systems and personalized monitoring platforms.

Nature communications, Nov 20, 2017

Multiple myeloma (MM) has benefited from significant advancements in treatment that have improved... more Multiple myeloma (MM) has benefited from significant advancements in treatment that have improved outcomes and reduced morbidity. However, the disease remains incurable and is characterized by high rates of drug resistance and relapse. Consequently, methods to select the most efficacious therapy are of great interest. Here we utilize a functional assay to assess the ex vivo drug sensitivity of single multiple myeloma cells based on measuring their mass accumulation rate (MAR). We show that MAR accurately and rapidly defines therapeutic susceptibility across human multiple myeloma cell lines to a gamut of standard-of-care therapies. Finally, we demonstrate that our MAR assay, without the need for extended culture ex vivo, correctly defines the response of nine patients to standard-of-care drugs according to their clinical diagnoses. This data highlights the MAR assay in both research and clinical applications as a promising tool for predicting therapeutic response using clinical samp...

Biosensors & bioelectronics, Jan 23, 2017

One major marker of nitrosative stress is the formation of 3-Nitrotyrosine (3-NT) from Tyrosine (... more One major marker of nitrosative stress is the formation of 3-Nitrotyrosine (3-NT) from Tyrosine (Tyr) by adding a nitro group (-NO2) with nitrating agents. Nitration of Tyr often causes loss of protein activity and is linked with many diseases. In this article, we detect 3-NT and discriminate it from Tyr with Differential Pulse Voltammetry (DPV) as it is a very important biomarker. We first examined redox (oxidation/reduction) properties and stability of 3-NT in detail. Second, we provided the Tyr and 3-NT discrimination with DPV and compared with the chromatography. We then explored the interaction of 3-NT and DNA oligonucleotides. Our findings demonstrate that 3-NT can be used as a new electrochemical indicator, which is able to detect hybridization of probe (single stranded DNA-ssDNA) and hybrid (double stranded DNA-dsDNA) both via 3-NT reduction and guanine oxidation signal changes at the same time. The signal differences enabled us to distinguish ssDNA and dsDNA without using a...

Optical Sensors 2017

In this work, we studied the multi-band plasmonic UT graphene antenna arrays. The proposed model ... more In this work, we studied the multi-band plasmonic UT graphene antenna arrays. The proposed model shows three different resonance frequencies. We show nearfield distributions of corresponding resonance frequencies and investigate the effect of the geometrical parameters, chemical potential, relaxation time, thickness of the substrate and different refractive index of the material on the spectral position of the UT-shaped graphene antenna.

Advanced Optical Materials, 2016

Plasmonics, 2015

Nanohole arrays in metal films allow extraordinary optical transmission (EOT); the phenomenon is ... more Nanohole arrays in metal films allow extraordinary optical transmission (EOT); the phenomenon is highly advantageous for biosensing applications. In this article, we theoretically investigate the performance of refractive index sensors, utilizing square and hexagonal arrays of nanoholes, that can monitor the spectral position of EOT signals. We present nearand far-field characteristics of the aperture arrays and investigate the influence of geometrical device parameters in detail. We numerically compare the refractive index sensitivities of the two lattice geometries and show that the hexagonal array supports larger figure-of-merit values due to its sharper EOT response. Furthermore, the presence of a thin dielectric film that covers the gold surface and mimics a biomolecular layer causes larger spectral shifts within the EOT resonance for the hexagonal array. We also investigate the dependence of the transmission responses on hole radius and demonstrate that hexagonal lattice is highly promising for applications demanding strong light transmission.

Journal of Electromagnetic Waves and Applications, 2015

CLEO: 2015, 2015

We demonstrate a field-portable optofluidic plasmonic sensing device, weighing 40 g and 7.5 cm in... more We demonstrate a field-portable optofluidic plasmonic sensing device, weighing 40 g and 7.5 cm in height, which merges plasmonic microarrays with dual-wavelength lensfree on-chip imaging for real-time monitoring of protein binding kinetics.

Photonics and Nanostructures - Fundamentals and Applications, 2015

ABSTRACT In this paper, we both experimentally and numerically introduce a dual-resonant metamate... more ABSTRACT In this paper, we both experimentally and numerically introduce a dual-resonant metamaterial based on subwavelength Jerusalem cross-shaped apertures. We numerically investigate the physical origin of the dual-resonant behavior, originating from the constituting aperture elements, through finite difference time domain calculations. Our numerical calculations show that at the dual-resonances, the aperture system supports large and easily accessible local electromagnetic fields. In order to experimentally realize the aperture system, we utilize a high-precision and lift-off free fabrication method based on electron-beam lithography. We also introduce a fine-tuning mechanism for controlling the dual-resonant spectral response through geometrical device parameters. Finally, we show the aperture system's highly advantageous far- and near-field characteristics through numerical calculations on refractive index sensitivity. The quantitative analyses on the availability of the local fields supported by the aperture system are employed to explain the grounds behind the sensitivity of each spectral features within the dual-resonant behavior. Possessing dual-resonance with large and accessible electromagnetic fields, JC-shaped apertures can be highly advantageous for wide range of applications demanding multiple spectral features with strong nearfield characteristics.

We present a high-throughput label-free protein microarray technology using large-area plasmonic ... more We present a high-throughput label-free protein microarray technology using large-area plasmonic nanohole arrays. Our detection principle is based on multi-spectral on-chip imaging enabling quantitative, realtime and high-throughput detection. We use low-cost and large area nanofabrication methods for manufacturing of plasmonic nanostructures with high optical qualities. Our system could become a powerful tool for biomedical sciences and pharmacology.

International Nano Letters, 2014

We theoretically investigate the optical forces generated by a high near-field resolution antenna... more We theoretically investigate the optical forces generated by a high near-field resolution antenna system through finite difference time domain calculations along with the Maxwell stress tensor method. Our antenna choice is bowtie-shaped nanostructures with small gap regions, exploiting propagating waveguide modes as well as localized surface plasmons. Our analysis shows that the antenna system supports large optical forces at the resonance wavelength where the near-field intensities as well as their gradients are the largest within the gap region. We show that the system exhibits much larger optical forces when the incident light polarization is along the bowtie gap as the system can effectively leverage the gap effect, compared to the case when the system is under the polarization normal to the gap. We also investigate the forces on a dielectric bead in the vicinity of the antennas for different positions to show the optical force characteristics of the bowtieshaped antennas. Finally, the force analysis on different bead radiuses demonstrates the trapping efficiency of our antenna system.

Advanced Optical Materials, 2013