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Athira Raveendran,1,* Suchithra Poilil Surendran,2,* Jinhui Ser,1 Khurshed Alam,1 Hoonsung Cho,1 Yong Yeon Jeong3 1Department of Materials Science & Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea; 2Department of Biomedical Sciences, Chonnam National University Medical School, Hwasun, 58128, Republic of Korea; 3Department of Radiology, Chonnam National University Hwasun Hospital, Hwasun, 58128, Republic of Korea*These authors contributed equally to this workCorrespondence: Hoonsung ChoDepartment of Materials Science & Engineering, Chonnam National University, Gwangju, 61186, Republic of KoreaTel +82-62-530-1717Fax +82-62-530-1699Email cho.hoonsung@jnu.ac.krYong Yeon JeongDepartment of Radiology, Chonnam National University Hwasun Hospital, Hwasun, 58128, Republic of KoreaEmail yjeong@jnu.ac.krIntroduction: Paclitaxel (PTX) is a conventional chemotherapeutic drug that effectively treats various cancers. The cellular uptake and therapeutic potential of PTX are limited by its slow penetration and low solubility in water. The development of cancer chemotherapy methods is currently facing considerable challenges with respect to the delivery of the drugs, particularly in targeting the tumor site without exerting detrimental effects on the healthy surrounding cells. One possibility for improving the therapeutic potential is through the development of tumor-targeted delivery methods.Methods: We successfully synthesized paclitaxel-MHI-148 conjugates (PTX-MHI) by coupling PTX with the tumor-targeting heptamethine cyanine dye MHI-148. Synthesis and purification were characterized using the absorbance spectrum and the results of time-of-flight mass spectrometry. Cellular uptake and cytotoxicity studies were conducted in vitro and in vivo.Results: PTX-MHI accumulates in tumor cells but not in normal cells, as observed by in vitro near-infrared fluorescent (NIRF) imaging along with in vivo NIRF imaging and organ biodistribution studies. We observed that MHI-148-conjugated PTX shows greater efficiency in cancer cells than PTX alone, even in the absence of light treatment. PTX-MHI could also be used for specific drug delivery to intracellular compartments, such as the mitochondria and lysosomes of cancer cells, to improve the outcomes of tumor-targeting therapy.Conclusion: The results indicated that PTX-MHI-mediated cancer therapy exerts an excellent inhibitory effect on colon carcinoma (HT-29) cell growth with low toxicity in normal fibroblasts (NIH3T3).Keywords: cancer therapy, colon cancer, bioconjugation, fluorescent dye, paclitaxel

Antimicrobial peptides (AMPs) are biologically active molecules involved in host defense present in a variety of organisms. They are an integral component of innate immunity, forming a front line of defense against potential pathogens, including antibiotic-resistant ones. Fishes are proven to be a prospective source of AMPs as they are constantly being challenged by a variety of pathogens and the AMPs are reported to play an inevitable role in fish immunity. Among them, β-defensins form one of the most studied multifunctional peptides with early evolutionary history and recently being considered as host defense peptides. The present study highlights the first-ever report on β-defensin AMP sequences from common goby (Pomatoschistus microps) and silver trevally (Pseudocaranx georgianus). A 192 bp cDNA fragment with an open reading frame encoding 63 amino acids (aa) comprising a 20 aa signal peptide region at the N-terminal was obtained from the mRNA of gill tissue of both P. microps and P. georgianus by RT-PCR. These peptide sequences when characterized in silico at the molecular level revealed a 43 aa cationic mature peptide with the signature intra-molecular disulphide bonded cysteine residue pattern ascertaining its β-defensin identity, further confirmed by phylogenetic analysis. The data collected will pave the way for further research on varied facets of the peptide-like, tissue level expressions, antimicrobial activities on commonly encountered pathogens, and its feasibility as a therapeutant in the aquaculture scenario.

This article presents a novel planar resonant method for complex permittivity measurement of planar dielectric substrates. Conventional planar dielectric sensors are composed of resonant structures, such as metamaterials, annular rings, and patch coupled to transmission lines to generate resonance. Here, we demonstrate a simple microstrip line resonator for complex permittivity measurement, and the generated resonant modes in the microstrip line are much like in 3-D conventional microwave cavities. The proposed prototype is distinguished from regular planar resonators due to the presence of a number of distinct electric and magnetic perturbable resonant modes and the absence of additional resonating structures in the design. The use of test samples in the commercially available thickness eliminates extensive sample preparation and possible air gaps or errors introduced due to the stacking of multiple dielectric layers. The microstrip line resonator fabricated on the FR4 substrate shows good agreement in measured permittivity and loss tangent values compared with the manufacturer’s datasheets. The proposed technique is a simple, fast, compact, and cost-effective measurement method for dielectric characterization, and it could be extended for other microwave transmission lines also.

A low cost planar resonant RF sensor for permittivity measurement of solid and liquid materials is proposed in this paper. A quarter wavelength resonator realized using microstrip line technology acts as a quasi static near field sensor. The resonant frequency of the sensor varies with the dielectric properties of the test sample in contact. A mathematical model based on finite element method is developed to determine the permittivity of dielectric test samples. The proposed sensor is designed to operate in 2.42 GHz ISM band. As a proof of concept, a prototype is fabricated on FR4 substrate of 1.6 mm thickness. The performance of the fabricated prototype is validated by measuring the permittivity of some commercially available substrates and vegetable oil samples. The measurement results showed a good agreement with the data available in the literature. The single port architecture of the planar sensor facilitates direct immersion in liquid samples. Moreover, this technique does not pose any limitations on thickness of solid test samples. The proposed submersible sensor is simple, compact, low cost and easy to fabricate which promotes its wide spread usage for microwave material characterization.

Antimicrobial peptides (AMPs) are an important element of the innate immune system of all living organisms and serve as a barrier that safeguards the organisms against a wide range of pathogens. Fishes are proven to be a prospective source of AMPs, and β-defensins form an important family of AMPs with potent antimicrobial, chemotactic and immunomodulatory activities. The present study reports a β-defensin AMP sequence (Lc-BD) from the Asian sea bass, Lates calcarifer, a commercially important fish species in tropical and subtropical regions of Asia and the Pacific. A 202-bp cDNA fragment with an open reading frame encoding 63 amino acids (aa) was obtained from the mRNA of gill tissue by RT-PCR. The deduced aa sequence of Lc-BD possessed a signal and a mature peptide region with 20 and 43 aa residues, respectively. Lc-BD was characterized at the molecular level, and a molecular weight of 5.24 kDa and a net charge of +4.5 was predicted for the mature peptide. The molecular characterization of Lc-BD revealed the presence of three intramolecular disulphide bonds involving the six conserved cysteine residues in the sequence, and the phylogenetic analysis of Lc-BD showed a close relationship with β-defensins from fishes like Siniperca chuatsi, Argyrosomus regius, Trachinotus ovatus and Oplegnathus fasciatus.

Antimicrobial peptides (AMPs) are biologically active molecules involved in host defense present in a variety of organisms. They are an integral component of innate immunity, forming a front line of defense against potential pathogens, including antibiotic-resistant ones. Fishes are proven to be a prospective source of AMPs as they are constantly being challenged by a variety of pathogens and the AMPs are reported to play an inevitable role in fish immunity. Among them, β-defensins form one of the most studied multifunctional peptides with early evolutionary history and recently being considered as host defense peptides. The present study highlights the first-ever report on β-defensin AMP sequences from common goby (Pomatoschistus microps) and silver trevally (Pseudocaranx georgianus). A 192 bp cDNA fragment with an open reading frame encoding 63 amino acids (aa) comprising a 20 aa signal peptide region at the N-terminal was obtained from the mRNA of gill tissue of both P. microps and P. georgianus by RT-PCR. These peptide sequences when characterized in silico at the molecular level revealed a 43 aa cationic mature peptide with the signature intra-molecular disulphide bonded cysteine residue pattern ascertaining its β-defensin identity, further confirmed by phylogenetic analysis. The data collected will pave the way for further research on varied facets of the peptide-like, tissue level expressions, antimicrobial activities on commonly encountered pathogens, and its feasibility as a therapeutant in the aquaculture scenario.

A low cost RF planar sensor for dielectric characterization and detection of adulteration in vegetable oils is proposed in this paper. The resonance characteristics of the metamaterial inspired sensor vary with the change in electrical properties of the liquid sample in contact. The sensor is designed to operate in 2.4 GHz ISM band and fabricated on a FR4 substrate of thickness 1.6 mm. A numerical model based on finite element method is developed to extract the relative permittivity of test samples. The sensor is experimentally validated by testing different vegetable oils and comparing the measurement results with values available in literature. As a proof of concept, the prototype is tested for adulteration in vegetable oils with different concentration of adulterant oil and their presence has successfully identified. The compactness, ease of fabrication and low manufacturing cost allow the planar sensor to be considered as promising alternative for dielectric characterization and detection of adulteration in vegetable oils. Moreover, the single port topology of the sensor allows direct submersion in the liquid samples and it also distinguishes materials of close permittivity.

The performance of microwave devices mainly depends on the properties of materials used in the fabrication. Knowledge of material properties at microwave frequencies is a prerequisite to select suitable materials for various microwave applications and vice versa. In this review, seven categories of materials and their applications in a microwave regime are elaborately discussed. The categories include magnetic materials, carbon-based materials, flexible or stretchable materials, biomaterials, phantoms, tunable materials and metamaterials. A brief overview of other important microwave materials such as low-loss ceramic dielectric materials, low-loss polymer ceramic composites, glass ceramics and multilayer ceramics is also given. The objective of this review is to expose the world of materials for wide microwave applications and thereby properly assisting the material selection for specific applications. Moreover, this review has dual significance. It helps material scientists to develop new materials and modify the properties of the available materials with respect to the application requirements. It also assists microwave engineers to select and use appropriate materials for different microwave applications.

A mechanical frequency reconfiguration technique in microstrip patch antennas for wireless sensor networks is presented in this paper. Frequency reconfiguration is achieved by mechanically changing the dielectric properties of the antenna and thereby obtaining a tunable frequency range from 2442 MHz to 2716 MHz. The gain of the prototype remains relatively flat throughout the reconfigured frequency range with a stable radiation pattern. The prototype is then studied as a fluid level sensor which operates based on the variation in resonant frequency with the rise or fall of the fluid in the dedicated channels engraved. The antenna is able to sense and transmit the information simultaneously with reduced complexity and less power consumption. Thus the proposed antenna could be used a fast wireless sensor for remote fluid level monitoring in wireless sensor networks.

A novel technique to achieve dual-band antenna with multifunctional beam is presented in this paper. Based on this technique, two different dual-band antennas; a Dielectric Resonator Antenna (DRA) and a microstrip antenna are proposed and their performances are compared. Each of these antenna configurations contain two radiating elements fed by single port dual coupling mechanism. The proposed antennas operate over DCS-1800 and WLAN bands. Both the antennas exhibit a bidirectional pattern with the beams oriented along +Z and -Z directions with the antennas placed in XY plane. DRA shows peak radiation efficiency of 93.47% and 97.38% within DCS and WLAN bands. Microstrip antenna shows peak radiation efficiency of 72.17% and 66.80% within the associated bands respectively. Dual-band characteristics along with oppositely oriented beam of the proposed antennas enable them to operate simultaneously in DCS and WLAN bands with minimum interference between radiating elements.