I. Combined cloud point extraction and Tween 20-stabilized gold nanoparticles for colorimetric assay of silver nanoparticles in environmental water This study investigated a simple, sensitive and selective method for the colorimetric assay of silver nanoparticles (AgNPs) using Triton X-114-based cloud point extraction (CPE) as a preconcentration step and Tween 20-stabilized gold nanoparticles (Tween-AuNPs) as a colorimetric probe. After heating beyond the cloud point temperature of Triton X-114, a solution containing Triton X-114 micelles and AgNPs separated into a surfactant-rich phase (small volume) and a dilute aqueous phase. AgNPs partitioned into a Triton X-114-rich phase through a hydrophobic interaction between Triton X-114 micelles and AgNPs. After phase separation, the concentrated AgNPs oxidized to form Ag+ upon adding H2O2. The generated Ag+ triggered the aggregation of Tween 20-AuNPs in a high-ionic-strength solution because the reduction of Ag+ on the AuNP surface enabled Tween 20 (stabilizer) to be removed from the NP surface. The efficiency of Triton X-114-based CPE of the AgNPs was found to be iv insensitive to their size and coating type. Under optimal extraction and detection conditions, the selectivity of this method for AgNPs was considerably higher than for other nanomaterials. The minimum detectable concentrations for 7, 22, and 54 nm AgNPs were measured to be 0.1, 420, and 600 ng/mL, respectively. This method was successfully applied to the analysis of 7 nm AgNPs in drinking water, tap water and seawater. Keyword: silver nanoparticles, gold nanoparticles, cloud point extraction, Tween-20, colorimetric assay II. Functionalized silver nanoparticles as an extracting and preconcentrating agent for detection of mercury ions In this research we provided highly sensitive and selective for fluorescence assay of combined polythymine oligonucleotide (PolyT) with silver nanoparticles (AgNPs) as an extracting agent to detect mercury ion in environmental water. According to previous researches, PolyT will form a hairpin structure in the presence of Hg2+, this structure provide several 3-D grooves that the fluorescent dye can inlay with it. SYBR Green I (SG) is a staining dye for DNA, when binding with single strand DNA, it shows low fluorescence. On the contrast, SG inlay with grooves of hairpin structure, it shows v 11-fold of fluorescence signal. Hence, we used SG as a fluorescence probe for Hg2+. We modified thiol group at the 5¡¦ of PolyT DNA, because of forming silver sulfur bond, PolyT will able to modified on the surface of AgNPs. PolyT33SH-AgNPs are the extracting and concentrating agent in Hg2+ solution, by the centrifugation, we collected the PolyT33SH-AgNPs. For the purpose of releasing PolyT from AgNPs¡¦ surface, we adding H2O2 to oxidize the AgNPs into Ag+. By mixing buffer and SG into previous solution, mercury ion could be detected. In this study, we successfully detecting Hg2+ in the aqueous solution contained drinking water and tap water. The detection limit in drinking water is 20 pM, which is below Environmental Protection Agency limit for Hg2+ in drinkable water (10 nM), the linear range is from 50-600 pM. On the other hand, the detection limit in tap water is 50 pM, linear range is from 100-700 pM. Keyword: silver nanoparticles, mercury ion, PolyT, SYBR Green I, thymine

While significant progress has been made in the treatment and management of cancer, challenges remain because of the complexity and the heterogeneous nature of the disease. The improvement that has been seen in survival rates reflects advancements not only in treatment, but also in early stage detection and diagnostics for certain cancers. In particular, early stage detection and treatment of cancer before it has metastasized to other organs has resulted in a dramatic improvement in patient survival rates. One area of research that has shown considerable promise in further advancing diagnostics and early cancer detection is nanotechnology. Specifically, semiconductor and metal nanoparticles have great potential to provide advanced technology platforms for ultrasensitive and multiplexed detection of disease markers and probe disease on the molecular level. Because they are in the same size regime as biological molecules, these nanoparticles exhibit unique interactions with proteins, nucleic acids and other biomarkers of interest for detecting and diagnosing disease. However, high-quality nanoparticles are often unsuited for use in complex biological environments because of their coatings and surface chemistry. In this work, we describe the design and development of polymer-coated nanoparticle imaging agents for use in blood, cell and tissue diagnostic applications. Low-molecular weight, amphiphilic polymers capable of noncovalent interactions with nanoparticle surface ligands and the aqueous environment were synthesized and characterized for use in nanoparticle coating applications. We demonstrate that the hydrophobic and hydrophilic interactions between the nanoparticle surface, the amphiphilic polymer and the aqueous solvent were able to drive the coating and water solubilization of quantum dots. Novel nanoparticle synthetic techniques were also developed using the amphiphilic polymers in a one-pot method to make high quality semiconductor and gold nanoparticles and stabilize and encapsulate the particles for transfer into water. Using the polymer functional groups as multidentate ligands, nanoparticles were synthesized with a high degree of size control and increased stability. In addition, by performing the synthesis in a noncoordinating amphiphilic solvent such as polyethylene glycol, nanoparticles were immediately transferred to water with the excess polymer forming a water soluble coating. Next, nanoparticle surface charge and how it relates to the nonspecific binding of nanoparticles in cells, tissues and other complex biological samples was studied. We have found that highly charged (negative and positive) particles exhibit significant nonspecific binding to biomolecules and other cellular components in biological environments. By reducing the surface charge through the incorporation of hydroxyl functional groups, we have nearly eliminated the nonspecific binding of quantum dots in blood, cells and tissues. Moreover, through crosslinking and altering the surface chemistry of the polymer-coated quantum dots, we have increased the stability of the nanoparticles while maintaining a small hydrodynamic size. Finally, we have investigated the use of the low-binding, hydroxyl quantum dots in tissue staining applications, where nonspecific binding presents a considerable challenge to detection sensitivity and specificity. A number of biomolecule conjugation techniques were examined for the coupling of quantum dots to antibody targeting molecules and preliminary staining experiments were performed.

Mitochondria are an attractive target for the design of cancer therapy. One of the mechanisms by which chemotherapeutics destroy cancer cells is by inducing apoptosis through extrinsic or intrinsic apoptotic pathways. Extrinsic pathways target cell surface receptors whilst intrinsic pathways target mitochondria. Several studies have shown cancer cell destruction through the extrinsic pathways, which target cancer-specific overexpressed growth factor receptors on the cell membrane. Although the mitochondria dependent apoptotic process is well understood, its application in cancer therapy is still not well developed. Therefore, to design an effective cancer therapy targeting mitochondria, a good understanding in mitochondria dependent apoptotic process is required. Recent developments in nanotechnology have enabled live cell investigations and non-destructive methods to obtain cellular information. The availability of such information would assist to design methods of targeted apoptosis induction. In view of this, I report on studies towards development of cancer therapy where nanoparticles (NPs) were targeted to human cell mitochondria for two purposes: (a) development of cell-imaging tools to investigate the fundamental cell biological pathways inside cells and (b) induction of apoptosis by targeting nanoparticles to mitochondria. Current medical and biological fluorescent imaging methods are mainly based on dye markers, which are limited in light emission per molecule, as well as photostability. Consequently, NPs are gaining prominence for molecular imaging because of their strong and stable fluorescence. Additionally, in order to get insight of mitochondrial molecular information, I investigated the use of optical properties of gold nanoparticles (Au NPs) for surface enhanced Raman spectroscopy (SERS). In this study, two types of Au NPs - nanospheres (Au NS) and nanorods (Au NR) were investigated. Results from this study showed the enhancement effect of Au NPs in Raman spectra of mitochondria, especially in the region from 1500 to 1600 cm-1. In this region, normal Raman spectra of mitochondria showed the presence of some understated Raman peaks probably due to the excitation wavelength dependence. Au NRs showed a larger enhancement effect than Au NS with respect to the penetration depth of the plasmonic nearfield enhancement effect. Although, the details of the enhancement mechanism are beyond the current studies, Au NPs could be enhancing vibrations of aromatic residues in proteins. This study therefore showed that Au NPs could enhance Raman spectra of mitochondria and in addition the shape of the nanoparticles had a significant effect on SERS spectra. In living cells, I investigated some transfection methods and targeting of NPs to mitochondria or cytosolic actin subunits. I tested the performance of three transfection reagents to deliver nanodiamonds (NDs) into living cells. Antibody functionalized NDs were targeted to mitochondria or cytosolic actin subunits. Three transfection reagents were used: cationic liposomes PULSin™, the cell penetrating peptide protamine, and oligosaccharide modified polypropylene imine (PPI) dendrimers. Fluorescence imaging results revealed that dendrimers were the most efficient in delivering ND conjugates to targeted organelles. Protamine-mediated transfections appeared to target ND conjugates to intended organelles, although there was a tendency of unfunctionalized NDs to be directed to the nucleus. PULSin™-mediated transfection formed ND aggregates regardless of the functionalization moiety. This reflected the unsuitability of the cationic liposome to mediate ND transfections. Further, I investigated the potential use of Au NPs for cell imaging and photothermal lysis of mitochondria inside cells. Just as above, I also tested the performance of the three-transfection reagents mentioned above on transfection capacity of Au NPs into living cells. Using transmission electron microscopy (TEM), oligosaccharide modified dendrimers showed the best transfection of functionalized Au NPs. Further experiments explored the use of the nearfield enhancement effect of Au NPs in combination with low-level laser irradiation (LLLI) to induce apoptosis in living cells. Analysis of the apoptotic process using cytochrome c release showed that Au NPs induced apoptosis most probably through mechanical disruption of the outer mitochondrial membrane. However, apoptosis was significantly accelerated in cells with mitochondrially targeted Au NRs than in cells without Au NRs. This study showed successful targeting of Au NPs to mitochondria in living cells, and demonstrated the potential of using Au NPs in combination with laser irradiation to induce the mitochondria dependent apoptotic pathway. In conclusion, the potential use of Au NPs in SERS of mitochondria and the application of NDs for cell imaging of intracellular organelles were demonstrated. Lastly, Au NPs were targeted to mitochondria in living cells and could induce apoptosis due to mechanical disruption of the outer mitochondrial membrane. Consequently, application of low-level laser irradiation to Au NP transfected cells accelerated the apoptotic process.

The unique properties of gold nanoparticles make them excellent candidates for applications in electronics, sensing, imaging, and photothermal therapy. Though abundant literature exists for isotropic gold nanoparticles, work on nanoparticles of different shapes has been gaining interest recently. Anisotropic gold nanoparticles, such as nanorods and nanoprisms, have tunable optical properties in the visible and near-infrared regions. Through synthesis and surface modification, the production of various shapes of these gold nanoparticles can be controlled to meet different applications. Two different types of gold nanorods were used in this thesis. The first type was stabilized with cetyltrimethylammonium bromide (CTAB) and had aspect ratios of 3-4 (defined as the nanorod length divided by the diameter). The second type was synthesized using CTAB and benzyldimethylhexadecylammonium chloride (BDAC) in a binary surfactant system which produced aspect ratios greater than 4. The nanorods were characterized with UV-Vis spectroscopy and transmission electron microscopy (TEM). Two types of bowl-shaped macrocyclic compounds called resorcinarenes were used to direct self-assembly of the nanorods. The first type of resorcinarene (R2S) consisted of thiol(SH)-terminated alkyl chains on both rims. The second type (R1S) contained thiol-terminated alkyl chains on only one rim. The monolayer formation of these resorcinarenes on planar gold surfaces was studied and characterized by FTIR spectroscopy. Resorcinarene-mediated assembly of gold nanorods was monitored with UV-Vis spectroscopy, dynamic light scattering (DLS), and TEM. In addition to gold nanorods, gold nanoprisms were synthesized through a kinetically-controlled reduction route in the presence of CTAB. The linking of nanoprisms using resorcinarenes was also explored.

<p>The fascinating optical properties of metallic nanostructures, dominated by collective oscillations of free electrons known as plasmons, open new opportunities for the development of devices fabrication based on noble metal nanoparticle composite materials. This thesis demonstrates a low-cost and versatile technique to produce stimuli-responsive ultrafast plasmonic nanostructures with reversible tunable optical properties. Albeit challenging, further control using thermal external stimuli to tune the local environment of gold nanoparticles embedded in VO2 host matrix would be ideal for the design of responsive functional nanocomposites. We prepared Au-VO2 nanocomposite thin films by the inverted cylindrical reactive magnetron sputtering (ICMS) known as hollow cathode magnetron sputtering for the first time and report the reversible tuning of surface plasmon resonance of Au nanoparticles by only adjusting the external temperature stimuli. The structural, morphological, interfacial analysis and optical properties of the optimized nanostructures have been studied. ICMS has been attracting much attention for its enclosed geometry and its ability to deposit on large area, uniform coating of smart nanocomposites at high deposition rate. Before achieving the aforementioned goals, a systematic study and optimization process of VO2 host matrix has been done by studying the influence of deposition parameters on the structural, morphological and optical switching properties of VO2 thin films. A reversible thermal tunability of the optical/dielectric constants of VO2 thin films by spectroscopic ellipsometry has been intensively also studied in order to bring more insights about the shift of the plasmon of gold nanoparticles imbedded in VO2 host matrix.</p>

Daktaro disertacijoje apibendrintų mokslinių tyrimų tikslas - pritaikyti aukso nanodaleles, skirtingas gliukozės oksidazes bei elektrai laidų polimerą polipirolą elektrodo modifikavimui bei gliukozės amperometriniam nustatymui biologiniais jutikliais. Aukso nanodalelės (AuND) imobilizuotos grafito elektrodo paviršiuje kartu su tirpiu elektronų pernašos tarpininku užtikrina efektyvesnę elektronų pernašą nuo gliukozės oksidazės (GOx) aktyvaus centro elektrodui fermentinės gliukozės oksidacijos metu. Naudojant AuND modifikuotus elektrodus amperometriniais biologiniais jutikliais registruojami apie 2 kartus didesni maksimalūs analiziniai signalai lyginant su elektrodu be AuND. Biologinių jutiklių tiesinės priklausomybės nuo substrato koncentracijos intervalas yra iki 10 mmol/L gliukozės ir aptikimo riba 0,08 mmol/L analitės. Po 66 dienų biologiniu jutikliu naudojančiu elektrodą modifikuotą GOx užregistruotas analizinis signalas sudarė 43 % pradinės signalo reikšmės, tuo tarpu naudojant 13,0 nm AuND ir GOx jutiklio analizinis signalas sudarė tik 22 % pradinės reikšmės. AuND esančios tiriamajame tirpale užtikrina efektyvesnę elektronų pernašą nuo gliukozės oksidazės aktyviojo centro elektrodui, kai jų koncentracija yra nuo 0,01 iki 0,60 nmol/L ir tirpale yra N-metilfenazino metosulfato. Naudojant 13,0 nm skersmens AuND, biologinio jutiklio aptikimo riba yra 0,05 mmol/L gliukozės, o tiesiškumo intervalas nuo 0,1 iki 10 mmol/L substrato. Taip pat nustatyta, kad kuo didesnė AuND... [toliau žr. visą tekstą] / The amperometric and voltammetric biosensors, based on gold nanoparticles, were designed and applied for biochemical, clinical and environment applications. Electrochemical biosensors are very selective, sensitive, fast and reusable. Gold, silver, platinum and SiO2 particles in the range 1–100 nm often provide an ideal remedy for immobilized enzymes with minimum diffusion limitations, promotion of electrochemical reaction, maximum surface area per mass unit and high effective achievement of enzymes direct wiring to electrode surface. Also, nanoparticles increase electron transfer rate between enzyme and an electrode surface. The aim of the work was to to apply different size nanoparticles, different glucose oxidases and electroconductive polymer polypyrrole for graphite electrode modification and determine the analytical characteristics of enzymatic biosensors for determination of glucose. It is established, that gold nanoparticles immobilized on graphite electrode with electron transfer mediator provide more effective electron transfer from glucose oxidase to electrode. Also, gold nanoparticles present in solution provide more effective electron transfer from enzyme to electrode when concentration of gold nanoparticles is ˂ 0.06 nmol/L and concentration of electron transfer mediator PMS is 2 mmol/L. The higher concentrations of nanoparticles in the solution make the electron transfer in the same system less efficient if compared with lower concentrations of nanoparticles... [to full text]

Daktaro disertacijoje apibendrintų mokslinių tyrimų tikslas - pritaikyti aukso nanodaleles, skirtingas gliukozės oksidazes bei elektrai laidų polimerą polipirolą elektrodo modifikavimui bei gliukozės amperometriniam nustatymui biologiniais jutikliais. Aukso nanodalelės (AuND) imobilizuotos grafito elektrodo paviršiuje kartu su tirpiu elektronų pernašos tarpininku užtikrina efektyvesnę elektronų pernašą nuo gliukozės oksidazės (GOx) aktyvaus centro elektrodui fermentinės gliukozės oksidacijos metu. Naudojant AuND modifikuotus elektrodus amperometriniais biologiniais jutikliais registruojami apie 2 kartus didesni maksimalūs analiziniai signalai lyginant su elektrodu be AuND. Biologinių jutiklių tiesinės priklausomybės nuo substrato koncentracijos intervalas yra iki 10 mmol/L gliukozės ir aptikimo riba 0,08 mmol/L analitės. Po 66 dienų biologiniu jutikliu naudojančiu elektrodą modifikuotą GOx užregistruotas analizinis signalas sudarė 43 % pradinės signalo reikšmės, tuo tarpu naudojant 13,0 nm AuND ir GOx jutiklio analizinis signalas sudarė tik 22 % pradinės reikšmės. AuND esančios tiriamajame tirpale užtikrina efektyvesnę elektronų pernašą nuo gliukozės oksidazės aktyviojo centro elektrodui, kai jų koncentracija yra nuo 0,01 iki 0,60 nmol/L ir tirpale yra N-metilfenazino metosulfato. Naudojant 13,0 nm skersmens AuND, biologinio jutiklio aptikimo riba yra 0,05 mmol/L gliukozės, o tiesiškumo intervalas nuo 0,1 iki 10 mmol/L substrato. Taip pat nustatyta, kad kuo didesnė AuND... [toliau žr. visą tekstą] / The amperometric and voltammetric biosensors, based on gold nanoparticles, were designed and applied for biochemical, clinical and environment applications. Electrochemical biosensors are very selective, sensitive, fast and reusable. Gold, silver, platinum and SiO2 particles in the range 1–100 nm often provide an ideal remedy for immobilized enzymes with minimum diffusion limitations, promotion of electrochemical reaction, maximum surface area per mass unit and high effective achievement of enzymes direct wiring to electrode surface. Also, nanoparticles increase electron transfer rate between enzyme and an electrode surface. The aim of the work was to to apply different size nanoparticles, different glucose oxidases and electroconductive polymer polypyrrole for graphite electrode modification and determine the analytical characteristics of enzymatic biosensors for determination of glucose. It is established, that gold nanoparticles immobilized on graphite electrode with electron transfer mediator provide more effective electron transfer from glucose oxidase to electrode. Also, gold nanoparticles present in solution provide more effective electron transfer from enzyme to electrode when concentration of gold nanoparticles is ˂ 0.06 nmol/L and concentration of electron transfer mediator PMS is 2 mmol/L. The higher concentrations of nanoparticles in the solution make the electron transfer in the same system less efficient if compared with lower concentrations of nanoparticles... [to full text]

The objectives of the doctoral thesis are following: (i) to design carbohydrate/oxygen enzymatic biofuel cells (EBFCs); (ii) to determine the factors limiting the performance of EBFCs; (iii) to characterise the bioelectrochemical properties of the enzymes adsorbed at conductive nanostructures and evaluate the viscoelasticity of these nanostructures. In this work 5-amino-1,10-phenanthroline (5AP) has been found to be the best redox mediator for glucose oxidase (GOx) enzyme among five studied phenanthroline derivatives with different functional groups. Later the 5AP cross-linked with GOx enzyme on a graphite rod electrode (GRE) was employed as an anode while GRE with co-immobilised horseradish peroxidase (HRP) and GOx was exploited as a cathode in order to design a glucose powered EBFC. A positively charged bi-functional thiol, N-(6-mercapto)hexylpyridinium (MHP), was exploited to electrostatically attach the cellobiose dehydrogenase (CDH) enzymes from Corynascus thermophilus (CtCDH) and Humicola insolens (HiCDH) to the gold nanoparticle (AuNP) surface. This coupling enabled a sufficient direct electron transfer between the enzymes and the AuNP-modified gold surface. Therefore, the HiCDH enzyme, showing better performance characteristics, was employed as an anodic biocatalyst in the designing of a mediatorless carbohydrate (glucose or lactose)/oxygen EBFC. The biocathode of the EBFC was based on bilirubin oxidase from Myrothecium verrucaria directly immobilised on the surface... [to full text] / Disertacinio darbo tikslai: (i) sukonstruoti fermentinius angliavandenių/deguonies biokuro elementus (FBKE); (ii) nustatyti FBKE veikimą ribojančius faktorius; (iii) apibūdinti fermentų, adsorbuotų laidžiose nanostruktūrose, bioelektrokatalizines charakteristikas ir įvertinti šių nanostruktūrų viskoelastines savybes. 5-amino-1,10-fenantrolino (5AF) junginys, iš penkių šiame darbe tirtų fenantrolinų junginių besiskiriančių funkcinėmis grupėmis, įvertintas kaip geriausias elektronų pernašos (EP) tarpininkas gliukozės oksidazės (GO) katalizuojamoje heterogeninėje reakcijoje. 5AF junginys kartu su GO fermentu (5AF/GO) buvo panaudotas anodinio elektrodo konstrukcijoje, o atitinkamai bifermentinė krienų peroksidazės (KP) ir GO sistema (KP/GO) – katodinio elektrodo konstrukcijoje. Šie elektrodai panaudoti gliukozės FBKE kūrimui. Teigiamą krūvį turintis bifunkcinis tiolinis N-(6-merkapto)heksilopiridinio (MHP) junginys panaudotas fermentų imobilizacijai aukso nanodalelių (AuND) paviršiuje elektrostatinės sąveikos būdu. AuND paviršiuje imobilizuoti celiobiozės dehidrogenazės (CDH) fermentai, išskirti iš Corynascus thermophilus (CtCDH) ir Humicola insolens (HiCDH) kamienų, sudarė fermentas-AuND sąsają įgalinančią tiesioginę EP. HiCDH fermentas kaip biokatalizatorius pritaikytas anodinio elektrodo konstrukcijoje AuND/MHP/HiCDH kuriant tiesiogine EP paremtus angliavandenių (gliukozės, laktozės)/deguonies FBKE. Bilirubino oksidazė (BO), tiesiogiai imobilizuota AuND paviršiuje (AuND/BO)... [toliau žr. visą tekstą]

Disertacinio darbo tikslai: (i) sukonstruoti fermentinius angliavandenių/deguonies biokuro elementus (FBKE); (ii) nustatyti FBKE veikimą ribojančius veiksnius; (iii) apibūdinti fermentų, adsorbuotų laidžiose nanostruktūrose, bioelektrokatalizines charakteristikas ir įvertinti šių nanostruktūrų viskoelastines savybes. 5-amino-1,10-fenantrolino (5AF) junginys, iš penkių šiame darbe tirtų fenantrolinų junginių besiskiriančių funkcinėmis grupėmis, įvertintas kaip geriausias elektronų pernašos (EP) tarpininkas gliukozės oksidazės (GO) katalizuojamoje heterogeninėje reakcijoje. 5AF junginys kartu su GO fermentu (5AF/GO) buvo panaudotas anodinio elektrodo konstrukcijoje, o atitinkamai bifermentinė krienų peroksidazės (KP) ir GO sistema (KP/GO) – katodinio elektrodo konstrukcijoje. Šie elektrodai panaudoti gliukozės FBKE kūrimui. Teigiamą krūvį turintis bifunkcinis tiolinis N-(6-merkapto)heksilopiridinio (MHP) junginys panaudotas fermentų imobilizacijai aukso nanodalelių (AuND) paviršiuje elektrostatinės sąveikos būdu. AuND paviršiuje imobilizuoti celiobiozės dehidrogenazės (CDH) fermentai, išskirti iš Corynascus thermophilus (CtCDH) ir Humicola insolens (HiCDH) kamienų, sudarė fermentas-AuND sąsają įgalinančią tiesioginę EP. HiCDH fermentas kaip biokatalizatorius pritaikytas anodinio elektrodo konstrukcijoje AuND/MHP/HiCDH kuriant tiesiogine EP paremtus angliavandenių (gliukozės, laktozės)/deguonies FBKE. Bilirubino oksidazė (BO, tiesiogiai imobilizuota AuND paviršiuje (AuND/BO)... [toliau žr. visą tekstą] / The objectives of the doctoral thesis are following: (i) to design carbohydrate/oxygen enzymatic biofuel cells (EBFCs); (ii) to determine the factors limiting the performance of EBFCs; (iii) to characterise the bioelectrochemical properties of the enzymes adsorbed at conductive nanostructures and evaluate the viscoelasticity of these nanostructures. In this work 5-amino-1,10-phenanthroline (5AP) has been found to be the best redox mediator for glucose oxidase (GOx) enzyme among five studied phenanthroline derivatives with different functional groups. Later the 5AP cross-linked with GOx enzyme on a graphite rod electrode (GRE) was employed as an anode while GRE with co-immobilised horseradish peroxidase (HRP) and GOx was exploited as a cathode in order to design a glucose powered EBFC. A positively charged bi-functional thiol, N-(6-mercapto)hexylpyridinium (MHP), was exploited to electrostatically attach the cellobiose dehydrogenase (CDH) enzymes from Corynascus thermophilus (CtCDH) and Humicola insolens (HiCDH) to the gold nanoparticle (AuNP) surface. This coupling enabled a sufficient direct electron transfer between the enzymes and the AuNP-modified gold surface. Therefore, the HiCDH enzyme, showing better performance characteristics, was employed as an anodic biocatalyst in the designing of a mediatorless carbohydrate (glucose or lactose)/oxygen EBFC. The biocathode of the EBFC was based on bilirubin oxidase from Myrothecium verrucaria directly immobilised on the surface... [to full text]

Histone deacetylase (HDAC) inhibition is an emerging novel therapeutic strategy in cancer therapy. HDAC inhibitors (HDACi) have shown ability to block angiogenesis and cell cycling, as well as initiate differentiation and apoptosis. In fact, suberoylanilide hydroxamic acid (SAHA) is the first in the class of HDACi approved by the FDA for the treatment of cutaneous T cell lymphoma. On the other hand, there is a sustained interest in the use of gold nanoparticles (AuNPs) for various cancer diagnostic and therapeutic applications - bioimaging, drug delivery, and binary therapy techniques such as photodynamic and photothermal therapies. This interest in AuNPs is facilitated by favorable attributes such as ease of fabrication, bioconjugation and biocompatibility, and unique optical and electronic properties. However, HDACi- and AuNPs- based antitumor agents are plagued with problems common to all chemotherapeutic agents such as lack of selectivity, which often results in systemic toxicity. Therefore, availability of a methodology to selectively deliver AuNPs and HDACi to cancer cells will significantly improve their therapeutic indices and lead to the identification of novel agents for use in diagnostic imaging and targeted cancer therapy applications.