Hybrid Photoactive Nanomaterial Composed of Gold Nanoparticles, Pheophorbide-A and Hyaluronic Acid as a Targeted Bimodal Phototherapy

강성훈,이용규,Md Nafiujjaman,Md. Nurunnabi,Li Li,Haseeb A. Khan,조광재,허강무 한국고분자학회 2015 Macromolecular Research Vol.23 No.5

Modern cancer research is largely focused on the design and development of multifunctional nanomaterials for cancer therapy and diagnosis. In this study, we fabricated a theranostic nanomaterial known as a photomedicine that combines a photothermal therapy (PTT), gold nanoparticles (AuNPs), a photodynamic therapy (PDT), pheophorbide- A (PheoA), and a cancer-targeting agent, hyaluronic acid (HA); this photomedicine also acts as a bimodal phototherapy. The combination of AuNPs and PheoA exerts a synergistic effect on PTT and PDT when irradiated by a laser source with a specific excitation wavelength. When excited by an external laser source, the hybrid nanomedicine generates singlet oxygen from PheoA while simultaneously generating heat from the AuNP, thus demonstrating a higher efficacy than any of the individual agents. The presence of HA on the outer surface of the Au accelerates the cellular uptake of the nanomedicine through CD44 receptors and prevents nonspecific accumulation of the drug in non-cancerous cells. The multifunctional nanoparticles have a diameter of ~70 nm and show constant stability in different conditions for up to a week of observation. In vitro and in vivo studies have demonstrated that multifunctional nanomaterials selectively target cells overexpressing CD44 receptor. In vitro photo-activity assays in the lung cancer cell line (A549) show that over 95% of the cells were dead upon laser irradiation. In brief, this newly developed nanomaterial rapidly accumulates in the tumor within 3 h of IV administration and inhibits tumor growth by 95% upon laser irradiation compared with a saline-treated tumor model observed for 24 days.

A hyaluronic acid nanogel for photo-chemo theranostics of lung cancer with simultaneous light-responsive controlled release of doxorubicin.

Khatun, Zehedina,Nurunnabi, Md,Nafiujjaman, Md,Reeck, Gerald R,Khan, Haseeb A,Cho, Kwang Jae,Lee, Yong-kyu RSC Pub 2015 Nanoscale Vol.7 No.24

<P>The combined delivery of photo-and chemo-therapeutic agents is an emerging strategy to overcome drug resistance in treating cancer, and controlled light-responsive drug release is a proven tactic to produce a continuous therapeutic effect for a prolonged duration. Here, a combination of light-responsive graphene, chemo-agent doxorubicin and pH-sensitive disulfide-bond linked hyaluronic acid form a nanogel (called a graphene-doxorubicin conjugate in a hyaluronic acid nanogel) that exerts an activity with multiple effects: thermo and chemotherapeutic, real-time noninvasive imaging, and light-glutathione-responsive controlled drug release. The nanogel is mono-dispersed with an average diameter of 120 nm as observed by using TEM and a hydrodynamic size analyzer. It has excellent photo-luminescence properties and good stability in buffer and serum solutions. Graphene itself, being photoluminescent, can be considered an optical imaging contrast agent as well as a heat source when excited by laser irradiation. Thus the nanogel shows simultaneous thermo-chemotherapeutic effects on noninvasive optical imaging. We have also found that irradiation enhances the release of doxorubicin in a controlled manner. This release synergizes therapeutic activity of the nanogel in killing tumor cells. Our findings demonstrate that the graphene-doxorubicin conjugate in the hyaluronic acid nanogel is very effective in killing the human lung cancer cell line (A549) with limited toxicity in the non-cancerous cell line (MDCK).</P>

Response of Feeding Amino Acids Supplemented Cottonseed Meal on Growth Performance and Digestibility of Early Weaned Cow Calves

Khan, A.G.,Azim, Atiya,Mirza, I.H. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.2

This study was designed to examine the response of feeding early weaning diets without and with amino acids supplemented cottonseed meal on growth performance and digestibility of early weaned cow calves. Fifteen 14-21 days old cross bred cow calves were randomly allotted to three experimental diets. Diet A comprised of milk replacer and concentrate feed whereas two isocaloric and iso-nitrogenous early weaning diets viz., B and C were prepared without and with lysine and methionine supplemented cottonseed meal, respectively. These early weaning diets were used as substitute of milk replacer for calves. Calves were placed in individual cages and fed twice daily for a period of 60 days. Daily feed intake, feed refused and weekly weight gain was recorded. Two digestibility trials I and II were performed at 5th and 9th week of the experiment, respectively. During the digestibility trial I, calves were fed on ad libitum basis whereas in trial II, calves were fed at 90% of their voluntary DMI. Feed, orts and feces samples were collected, weighed daily, composited, subsampled and analysed for DM and CP. Results indicated that weight gain of calves was (p<0.05) higher on diets A (0.63 kg/d/calf) and C (0.64 kg/d/calf) compared to calves on diet B (0.57 kg/d/calf). Significantly (p<0.05) less daily DMI was observed on diet A (1.48 kg) compared to early weaning diets B (1.70 kg) and C (1.72 kg). The feed efficiency was (p<0.05) better on diet A (2.33) compared to diets B (2.95) and C (2.65). The economic efficiency was noticed to be better on diets B and C compared to diet A. In trial I, digestibility of DM and CP of diet A was (p<0.05) higher than diets B and C. Whereas in trial II, digestibility of DM and CP of diet A was (p<0.05) less than diets B and C. It was concluded that early weaning diet based on lysine and methionine supplemented cottonseed meal produced better weight gain and feed efficiency compared to non-supplemented cottonseed meal based diet.

Calorimetric studies of the crystallization process in a-Se75S25-xAgx chalcogenide glasses

Shamshad A. Khan,F.S. Al-Hazmi,A.S. Faidah,A.A. Al-Ghamdi 한국물리학회 2009 Current Applied Physics Vol.9 No.3

Calorimetric studies of amorphous Se75S25-xAgx (x = 2, 4, 6 and 8) chalcogenide glasses are made at different heating rates (5, 10, 15 and 20 K/min) under non-isothermal condition using Differential scanning calorimetry. The values of glass transition temperature and crystallization temperature are observed to be composition and heating rate dependence. From the heating rate dependence of glass transition temperature and crystallization temperature, the activation energy for structural relaxation (△Et), the activation energy of crystallization (△Ec) and the order parameter (n) have been calculated. It is observed that Se75S19Ag6 has a minimum value of activation energy for structural relaxation (△Et), which indicates that this particular glass has a larger probability to jump to a state of lower configurational energy and higher stability in the glassy region. On the basis of the obtained experimental data the temperature difference (Tc - Tg) is found to be maximum for Se75S19Ag6, which further indicate that this glass is the thermally most stable in the entire composition range of investigation. Calorimetric studies of amorphous Se75S25-xAgx (x = 2, 4, 6 and 8) chalcogenide glasses are made at different heating rates (5, 10, 15 and 20 K/min) under non-isothermal condition using Differential scanning calorimetry. The values of glass transition temperature and crystallization temperature are observed to be composition and heating rate dependence. From the heating rate dependence of glass transition temperature and crystallization temperature, the activation energy for structural relaxation (△Et), the activation energy of crystallization (△Ec) and the order parameter (n) have been calculated. It is observed that Se75S19Ag6 has a minimum value of activation energy for structural relaxation (△Et), which indicates that this particular glass has a larger probability to jump to a state of lower configurational energy and higher stability in the glassy region. On the basis of the obtained experimental data the temperature difference (Tc - Tg) is found to be maximum for Se75S19Ag6, which further indicate that this glass is the thermally most stable in the entire composition range of investigation.

Production of a monoclonal antibody against a mannose-binding protein of <i>Acanthamoeba culbertsoni</i> and its localization

Kang, A-Young,Park, A-Young,Shin, Ho-Joon,Khan, Naveed Ahmed,Maciver, Sutherland K.,Jung, Suk-Yul Elsevier 2018 Experimental parasitology Vol.192 No.-

<P>Amoebae from the genus Acanthamoeba are facultative pathogens of humans and other animals. In humans they most frequently infect the eye causing a sight threatening infection known as Acanthamoeba keratitis (AK), and also cause an often fatal encephalitis (GAE). A mannose-binding protein (MBP) has been identified as being important for Acanthamoeba infection especially in AK. This lectin has previously been characterized from Acanthamoeba castellanii as consisting of multiple 130 kDa subunits. MBP expression correlates with pathogenic potential and is expressed in a number of Acanthamoeba species. Here we report the purification of a similar lectin from Acanthamoeba culbertsoni and the production of a monoclonal antibody to it. The A. culbertsoni MBP was isolated by affinity chromatography using alpha-D-mannose agarose and has an apparent molecular weight of 83 kDa. The monoclonal antibody is an IgM that is useful in both western blots and immunofluorescence. We expect that this antibody will be useful in the study of the pathology of A. culbertsoni and in its identification in clinical samples.</P>

Synthesis of Tetrazolo[1,5-a]quinoxaline based Azetidinones & Thiazolidinones as Potent Antibacterial & Antifungal Agents

Kumar, Shiv,Khan, S.A.,Alam, Ozair,Azim, Rizwan,Khurana, Atul,Shaquiquzzaman, M.,Siddiqui, Nadeem,Ahsan, Waquar Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

4-Chlorotetrazolo[1,5-a]quinoxaline (III) was synthesized by azide (2+3) cycloaddition of 2,3-dichloroquinoxaline (II). Compound (III) on further refluxing with hydrazine hydrate furnished 4-hydrazinotetrazolo[1,5-a]quinoxaline (IV). Further refluxing of (IV) with different aromatic aldehydes in methanol yielded corresponding Schiff's bases V(a-j). Various 4-aminotetrazolo[1,5-a]quinoxaline based azetidinones VII(a-j) were synthesized by stirring the compounds V(a-j), at low temperature, with equimolar mixture of chloroacetylchloride & triethylamine in dry benzene, while 4-aminotetrazolo[1,5-a]quinoxaline based thiazolidinones VIII(a-j) were synthesized by refluxing Schiff's bases V(a-j) with thioglycolic acid in oil-bath. The structures of all the compounds were confirmed on the basis of $^1H$-NMR & FT-IR spectral data. All the newly synthesized compounds were screened for in-vitro antimicrobial activity against E. coli, S. aureus, K. pneumoniae & P. aeruginosa & antifungal activity against C. albicans. Few of them have exhibited the promising activity.

Synthesis of Tetrazolo[1,5-a]quinoxaline based Azetidinones & Thiazolidinones as Potent Antibacterial & Antifungal Agents

Shiv Kumar,S. A. Khan,Ozair Alam,Rizwan Azim,Atul Khurana,M. Shaquiquzzaman,Nadeem Siddiqui,Waquar Ahsan 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

4-Chlorotetrazolo[1,5-a]quinoxaline (III) was synthesized by azide (2+3) cycloaddition of 2,3-dichloroquinoxaline (II). Compound (III) on further refluxing with hydrazine hydrate furnished 4-hydrazinotetrazolo[1,5-a]quinoxaline (IV). Further refluxing of (IV) with different aromatic aldehydes in methanol yielded corresponding Schiff’s bases V(a-j). Various 4-aminotetrazolo[1,5-a]quinoxaline based azetidinones VII(a-j) were synthesized by stirring the compounds V(a-j), at low temperature, with equimolar mixture of chloroacetylchloride & triethylamine in dry benzene, while 4-aminotetrazolo[1,5-a]quinoxaline based thiazolidinones VIII(a-j) were synthesized by refluxing Schiff’s bases V(a-j) with thioglycolic acid in oil-bath. The structures of all the compounds were confirmed on the basis of ^1H-NMR & FT-IR spectral data. All the newly synthesized compounds were screened for in-vitro antimicrobial activity against E. coli, S. aureus, K. pneumoniae & P. aeruginosa & antifungal activity against C. albicans. Few of them have exhibited the promising activity.

Novel Ag@TiO₂ nanocomposite synthesized by electrochemically active biofilm for nonenzymatic hydrogen peroxide sensor

Khan, M.M.,Ansari, S.A.,Lee, J.,Cho, M.H. Elsevier 2013 Materials science & engineering. C, Materials for Vol.33 No.8

A novel nonenzymatic sensor for H<SUB>2</SUB>O<SUB>2</SUB> was developed based on an Ag@TiO<SUB>2</SUB> nanocomposite synthesized using a simple and cost effective approach with an electrochemically active biofilm. The optical, structural, morphological and electrochemical properties of the as-prepared Ag@TiO<SUB>2</SUB> nanocomposite were examined by UV-vis spectroscopy, X-ray diffraction, transmission electron microscopy and cyclic voltammetry (CV). The Ag@TiO<SUB>2</SUB> nanocomposite was fabricated on a glassy carbon electrode (GCE) and their electrochemical performance was analyzed by CV, differential pulse voltammetry and electrochemical impedance spectroscopy. The Ag@TiO<SUB>2</SUB> nanocomposite modified GCE (Ag@TiO<SUB>2</SUB>/GCE) displayed excellent performance towards H<SUB>2</SUB>O<SUB>2</SUB> sensing at -0.73V in the linear response range from 0.83μM to 43.3μM, within a detection limit and sensitivity of 0.83μM and ~65.2328+/-0.01μAμM<SUP>-1</SUP>cm<SUP>-2</SUP>, respectively. In addition, Ag@TiO<SUB>2</SUB>/GCE exhibited good operational reproducibility and long term stability.

A 3D CFD analysis of flow past a hipped roof with comparison to industrial building standards

Khalid Khalil,Huzafa Khan,Divyansh Chahar,Jamie F. Townsend,Zeeshan A. Rana 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.34 No.6

Three-dimensional (3D) computational fluid dynamics (CFD) analysis of flow around a hipped-roof building representative of UK inland conditions are conducted. Unsteady simulations are performed using three variations of the k–ϵ RANS turbulence model namely, the Standard, Realizable, and RNG models, and their predictive capability is measured against current European building standards. External pressure coefficients and wind loading are found through the BS 6399-2:1997 standard (obsolete) and the current European standards (BS EN 1991-1-4:2005 and A1:20101). The current European standard provides a more conservative wind loading estimate compared to its predecessor and the k–ϵ RNG model falls within 15% of the value predicted by the current standard. Surface shear stream-traces and Q-criterion were used to analyze the flow physics for each model. The RNG model predicts immediate flow separation leading to the creation of vortical structures on the hipped-roof along with a larger separation region. It is observed that the Realizable model predicts the side vortex to be a result of both the horseshoe vortex and the flow deflected off it. These model-specific aerodynamic features present the most disparity between building standards at leeward roof locations. Finally, pedestrian comfort and safety criteria are studied where the k–ϵ Standard model predicts the most ideal pedestrian conditions and the Realizable model yields the most conservative levels.

Optical band gap and optical constants in a-Se80Te20 xPbx thin films

Shamshad A. Khan,M. Zulfequar,M. Husain 한국물리학회 2005 Current Applied Physics Vol.5 No.6

The optical constants (absorption coecient, refractive index, extention coecient, real and imaginary part of dielectric con-stant) have been studied for a-Se80Te20. xPbx (wherex = 0,2,6,10) thin lms as a function of photon energy in the wave length range(5001000nm). It has been found that the optical band gap increases while the refractive index and the extinction coecient (k)decreases on incorporation of lead in SeTe system. The value of absorption coecient (a) and the extinction coecient (k)increases, while the value of refractive index (n) decreases with incident photon energy. The results are interpreted in terms ofthe change in concentration of localized states due to the shift in fermi level..