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1.
ChemSusChem ; : e202400546, 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-39037891

ABSTRACT

Carbon porous materials containing nitrogen functionalities and encapsulated iron-based active sites have been suggested as electrocatalysts for energy conversion, however their applications to the hydrogenation of organic substrates via electrocatalytic hydrogenation (ECH) remain unexplored. Herein, we report on a Fe@C:N material synthesized with an adapted annealing procedure and tested as electrocatalyst for the hydrogenation of benzaldehyde. Using different concentrations of the organic, and electrolysis coupled to gas chromatography experiments, we demonstrate that it is possible to use such architectures for the ECH of unsaturated organics. Potential control experiments show that ECH faradaic efficiencies >70% are possible in acid electrolytes, while maintaining selectivity for the alcohol over the pinacol dimerization product. Estimates of product formation rates and turnover frequency (TOF) values suggest that these carbon-encapsulated architectures can achieve competitive performance in acid electrolytes relative to both base and precious metal electrodes.

2.
Bioelectrochemistry ; 156: 108618, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37988978

ABSTRACT

Microbial Fuel Cells (MFC) convert energy stored in chemicals into electrical energy thanks to exoelectrogenic microorganisms who also play a crucial role in geochemical cycles in their natural environment, including that of iron. In this study, we investigated paleomarine sediments as inoculum for bioanode development in MFCs. These sediments were formed under anoxic conditions ca. 113 million years ago and are rich in clay minerals, organic matter, and iron. The marlstone inoculum was incubated in the anolyte of an MFC using acetate as the added electron donor and ferricyanide as the electron acceptor in the catholyte. After seven weeks of incubation, the current density increased to 0.15 mA.cm-2 and a stable + 700 mV open circuit potential was reached. Community analysis revealed the presence of two exoelectrogenic bacterial genera, Geovibrio and Geobacter. Development of electroactive biofilms was correlated to bulk chemical transformations of the sediment inoculum with an increase in the Fe(II) to Fetotal ratio. Comparisons to sediments sterilized prior to inoculation confirmed that bioanode development derives from the native microbiota of these paleomarine sediments. This study illustrates the feasibility of developing exoelectrogenic biofilms from iron-rich marlstone and has implications for the role of such bacteria in broader paleoenvironmental phenomena.


Subject(s)
Bioelectric Energy Sources , Iron , Electrodes , Bacteria , Electricity , Bioelectric Energy Sources/microbiology , Biofilms
3.
JACS Au ; 3(6): 1623-1633, 2023 Jun 26.
Article in English | MEDLINE | ID: mdl-37388690

ABSTRACT

Conjugation of biomolecules on the surface of nanoparticles (NPs) to achieve active targeting is widely investigated within the scientific community. However, while a basic framework of the physicochemical processes underpinning bionanoparticle recognition is now emerging, the precise evaluation of the interactions between engineered NPs and biological targets remains underdeveloped. Here, we show how the adaptation of a method currently used to evaluate molecular ligand-receptor interactions by quartz crystal microbalance (QCM) can be used to obtain concrete insights into interactions between different NP architectures and assemblies of receptors. Using a model bionanoparticle grafted with oriented apolipoprotein E (ApoE) fragments, we examine key aspects of bionanoparticle engineering for effective interactions with target receptors. We show that the QCM technique can be used to rapidly measure construct-receptor interactions across biologically relevant exchange times. We contrast random adsorption of the ligand at the surface of the NPs, resulting in no measurable interaction with target receptors, to grafted oriented constructs, which are strongly recognized even at lower graft densities. The effects of other basic parameters impacting the interaction such as ligand graft density, receptor immobilization density, and linker length were also efficiently evaluated with this technique. Dramatic changes in interaction outcomes with subtle alterations in these parameters highlight the general importance of measuring the interactions between engineered NPs and target receptors ex situ early on in the construct development process for the rational design of bionanoparticles.

4.
Bioelectrochemistry ; 151: 108394, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36739700

ABSTRACT

Exo-electrogenic microorganisms have been extensively studied for their ability to transfer electrons with solid surfaces using a large variety of metabolic pathways. Most of the studies on these microorganisms consist in the replacement of solid electron acceptors such as Fe(III) oxides found in nature by electrodes with the objective of generating harvestable current in devices such as microbial fuel cells. In this study we show how the presence of solid ferric oxide (Fe2O3) particles in the inoculum during bio-anode development influences extracellular electron transfer to the electrode. Amplification and sequencing of the 16S rRNA (V4-V5 region) show bacteria and archaea communities with a large predominance of the Pelobacter genus, which is known to be phylogenetically close to the Geobacter genus, regardless of the presence or absence of ferric oxide in the inoculum. Data indicate that the bacteria at the bio-anode surface can preferentially utilize solid ferric oxide as terminal electron acceptors instead of the anode, though extracellular electron transfer to the anode can be restored by removing the particles. Mixed inoculum commonly used to develop bioanodes may produce similar bacterial communities with divergent electrochemical responses due to the presence of alternate electron acceptors, with direct implications for microbial fuel cell performance.


Subject(s)
Bioelectric Energy Sources , Deltaproteobacteria , Geobacter , Ferric Compounds/metabolism , Oxides , Electrons , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/metabolism , Bacteria/metabolism , Deltaproteobacteria/genetics , Bioelectric Energy Sources/microbiology , Geobacter/metabolism , Electrodes , Biofilms
5.
Bioconjug Chem ; 33(3): 429-443, 2022 03 16.
Article in English | MEDLINE | ID: mdl-35167255

ABSTRACT

The progress achieved over the last three decades in the field of bioconjugation has enabled the preparation of sophisticated nanomaterial-biomolecule conjugates, referred to herein as bionanoconstructs, for a multitude of applications including biosensing, diagnostics, and therapeutics. However, the development of bionanoconstructs for the active targeting of cells and cellular compartments, both in vitro and in vivo, is challenged by the lack of understanding of the mechanisms governing nanoscale recognition. In this review, we highlight fundamental obstacles in designing a successful bionanoconstruct, considering findings in the field of bionanointeractions. We argue that the biological recognition of bionanoconstructs is modulated not only by their molecular composition but also by the collective architecture presented upon their surface, and we discuss fundamental aspects of this surface architecture that are central to successful recognition, such as the mode of biomolecule conjugation and nanomaterial passivation. We also emphasize the need for thorough characterization of engineered bionanoconstructs and highlight the significance of population heterogeneity, which too presents a significant challenge in the interpretation of in vitro and in vivo results. Consideration of such issues together will better define the arena in which bioconjugation, in the future, will deliver functional and clinically relevant bionanoconstructs.


Subject(s)
Biological Products , Nanostructures
6.
Nanoscale Adv ; 3(9): 2397-2410, 2021 May 04.
Article in English | MEDLINE | ID: mdl-36134166

ABSTRACT

The field of nanomedicine has the potential to be a game-changer in global health, with possible applications in prevention, diagnostics, and therapeutics. However, despite extensive research focus and funding, the forecasted explosion of novel nanomedicines is yet to materialize. We believe that clinical translation is ultimately hampered by a lack of understanding of how nanoparticles really interact with biological systems. When placed in a biological environment, nanoparticles adsorb a biomolecular layer that defines their biological identity. The challenge for bionanoscience is therefore to understand the evolution of the interactions of the nanoparticle-biomolecules complex as the nanoparticle is trafficked through the intracellular environment. However, to progress on this route, scientists face major challenges associated with isolation of specific intracellular compartments for analysis, complicated by the diversity of trafficking events happening simultaneously and the lack of synchronization between individual events. In this perspective article, we reflect on how magnetic nanoparticles can help to tackle some of these challenges as part of an overall workflow and act as a useful platform to investigate the bionano interactions within the cell that contribute to this nanoscale decision making. We discuss both established and emerging techniques for the magnetic extraction of nanoparticles and how they can potentially be used as tools to study the intracellular journey of nanomaterials inside the cell, and their potential to probe nanoscale decision-making events. We outline the inherent limitations of these techniques when investigating particular bio-nano interactions along with proposed strategies to improve both specificity and resolution. We conclude by describing how the integration of magnetic nanoparticle recovery with sophisticated analysis at the single-particle level could be applied to resolve key questions for this field in the future.

7.
Front Chem ; 8: 593932, 2020.
Article in English | MEDLINE | ID: mdl-33240854

ABSTRACT

Nitrogen-free amorphous carbon thin films prepared via sputtering followed by graphitization, were used as precursor materials for the creation of N-doped carbon electrodes with varying degrees of amorphization. Incorporation of N-sites was achieved via nitrogen plasma treatments which resulted in both surface functionalization and amorphization of the carbon electrode materials. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used to monitor composition and carbon organization: results indicate incorporation of predominantly pyrrolic-N sites after relatively short treatment cycles (5 min or less), accompanied by an initial etching of amorphous regions followed by a slower process of amorphization of graphitized clusters. By leveraging the difference in the rate of these two processes it was possible to investigate the effects of chemical N-sites and C-defect sites on their electrochemical response. The materials were tested as metal-free electrocatalysts in the oxygen reduction reaction (ORR) in alkaline conditions. We find that the introduction of predominantly pyrrolic-N sites via plasma modification results in improvements in selectivity in the ORR, relative to the nitrogen-free precursor material. Introduction of defects through prolonged plasma exposure has a more pronounced and beneficial effect on ORR descriptors than introduction of N-sites alone, leading to both increased onset potentials, and reduced hydroperoxide yields relative to the nitrogen-free carbon material. Our results suggest that increased structural disorder/heterogeneity results in the introduction of carbon sites that might either serve as main activity sites, or that enhance the effects of N-functionalities in the ORR via synergistic effects.

8.
Bioelectrochemistry ; 136: 107621, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32791485

ABSTRACT

Grafting of aryldiazonium cations bearing a p-mannoside functionality over microbial fuel cell (MFC) anode materials was performed to investigate the ability of aryl-glycoside layers to regulate colonisation by biocatalytic biofilms. Covalent attachment was achieved via spontaneous reactions and via electrochemically-assisted grafting using potential step experiments. The effect of different functionalisation protocols on MFC performance is discussed in terms of changes in wettability, roughness and electrochemical response of modified electrodes. Water contact angle measurements (WCA) show that aryl-mannoside grafting yields a significant increase in hydrophilic character. Surface roughness determinations via atomic force microscopy (AFM) suggest a more disordered glycan adlayer when electrografting is used to facilitate chemisorption. MFCs were used as living sensors to successfully test the coated electrodes: the response of the MFCs in terms of start-up time was accelerated when compared to that of MFC equipped with non-modified electrodes, this suggests a faster development of a mature biofilm community resulting from aryldiazonium modifications, as confirmed by cyclic voltammetry of MFC anodes. These results therefore indicate that modification with glycans offers a bioinspired route to accelerating biofilm colonisation without any adverse effects on final MFC outputs.


Subject(s)
Bacteria/metabolism , Bioelectric Energy Sources , Electrodes , Microbiota , Biofilms , Electricity , Glycosylation , Surface Properties
9.
Small ; 15(48): e1902081, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31210002

ABSTRACT

Metal-free carbon electrodes with well-defined composition and smooth topography are prepared via sputter deposition followed by thermal treatment with inert and reactive gases. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy show that three carbons of similar N/C content that differ in N-site composition are thus prepared: an electrode consisting of almost exclusively graphitic-N (NG ), an electrode with predominantly pyridinic-N (NP ), and one with ≈1:1 NG :NP composition. These materials are used as model systems to investigate the activity of N-doped carbons in the oxygen reduction reaction (ORR) using voltammetry. Results show that selectivity toward 4e-reduction of O2 is strongly influenced by the NG /NP site composition, with the material possessing nearly uniform NG /NP composition being the only one yielding a 4e-reduction. Computational studies on model graphene clusters are carried out to elucidate the effect of N-site homogeneity on the reaction pathway. Calculations show that for pure NG -doping or NP -doping of model graphene clusters, adsorption of hydroperoxide and hydroperoxyl radical intermediates, respectively, is weak, thus favoring desorption prior to complete 4e-reduction to hydroxide. Clusters with mixed NG /NP sites display synergistic effects, suggesting that co-presence of these sites improves activity and selectivity by achieving high theoretical reduction potentials while facilitating retention of intermediates.

10.
RSC Adv ; 9(7): 4063-4071, 2019 Jan 25.
Article in English | MEDLINE | ID: mdl-35518062

ABSTRACT

Nitrogen incorporated carbon materials play an important role in electrochemical energy conversion technologies from fuel cells to capacitive storage devices. This work investigates the effects of nitrogen incorporation on capacitance, work function and semiconductor properties of amorphous carbon thin film electrodes. Nitrogenated electrodes (a-C:N) electrodes were synthesized via magnetron sputtering and characterized using X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy (UPS), Raman spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). EIS was carried in both aqueous (0.1 M KCl) and organic (0.1 M TBAPF6/acetonitrile) electrolytes to discriminate between pseudocapacitive contributions and changes to semiconductor properties of the materials arising from structural and chemical disruption of the graphitic carbon scaffold. Raman and UPS spectroscopy both suggest that nitrogen incorporation increases the metallic character of the disordered carbon matrix at low-intermediate concentrations, whereas further nitrogen incorporation results in significantly more defective carbon with small graphitic cluster size. EIS studies in 0.1 M KCl indicate that the capacitance of a-C:N electrodes increases relative to nitrogen-free a-C electrodes due to a combination of microroughness and pseudocapacitive contributions in parallel to those of the double layer capacitance. Results in 0.1 M TBAPF6 in acetonitrile which are dominated by the interfacial capacitance, show that initial nitrogen incorporation into the disordered carbon scaffold compensates for p-type properties in the disordered carbon matrix, resulting in an increase in metallic character. Greater levels of nitrogenation, are instead disruptive and increase defect density while decreasing the double layer capacitance.

11.
ACS Appl Bio Mater ; 1(3): 825-832, 2018 Sep 17.
Article in English | MEDLINE | ID: mdl-34996174

ABSTRACT

A mild and efficient surface modification protocol for the preparation of ß-cyclodextrin (ßCD) modified surfaces through aryldiazonium-mediated grafting is reported. Monosubstituted 6-O-aminophenol-ß-cyclodextrin (amßCD) was synthesized through a three-step protocol. This compound was found to form supramolecular aggregates in aqueous solutions at relatively low concentrations via cavity-directed self-assembly. Disruption of these supramolecular structures through judicious choice of solvent was found to be essential for the formation of the reactive aryldiazonium species from the amino-phenolic precursor and for spontaneous surface grafting from aqueous solutions. Cyclodextrin thin films were prepared on carbon macroscopic substrates and electrodes and were characterized via infrared reflectance absorption spectroscopy (IRRAS), cyclic voltammetry, and water contact angle measurements. Protein adsorption studies demonstrated that ßCD adlayers reduced nonspecific protein adsorption. ßCD moieties in adlayers can be used nonetheless for specific host-guest complexation and are grafted at the surface with monolayer coverage (1.2 × 10-10 mol cm-2) as demonstrated via experiments using ferrocene, a redox probe. Finally, cyclodextrin covalent immobilization was demonstrated also on stainless steel and polyamide samples, two substrates with wide ranging technological applications.

12.
Langmuir ; 33(17): 4198-4206, 2017 05 02.
Article in English | MEDLINE | ID: mdl-28398737

ABSTRACT

Various forms of carbon are known to perform well as biomaterials in a variety of applications and an improved understanding of their interactions with biomolecules, cells, and tissues is of interest for improving and tailoring their performance. Nanoplasmonic sensing (NPS) has emerged as a powerful technique for studying the thermodynamics and kinetics of interfacial reactions. In this work, the in situ adsorption of two proteins, bovine serum albumin and fibrinogen, were studied at carbon surfaces with differing chemical and optical properties using nanoplasmonic sensors. The carbon material was deposited as a thin film onto NPS surfaces consisting of 100 nm Au nanodisks with a localized plasmon absorption peak in the visible region. Carbon films were fully characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and spectroscopic ellipsometry. Two types of material were investigated: amorphous carbon (a-C), with high graphitic content and high optical absorptivity, and hydrogenated amorphous carbon (a-C:H), with low graphitic content and high optical transparency. The optical response of the Au/carbon NPS elements was modeled using the finite difference time domain (FDTD) method, yielding simulated analytical sensitivities that compare well with those observed experimentally at the two carbon surfaces. Protein adsorption was investigated on a-C and a-C:H, and the protein layer thicknesses were obtained from FDTD simulations of the expected response, yielding values in the 1.8-3.3 nm range. A comparison of the results at a-C and a-C:H indicates that in both cases fibrinogen layers are thicker than those formed by albumin by up to 80%.


Subject(s)
Carbon/chemistry , Fibrinogen/chemistry , Serum Albumin, Bovine/chemistry , Adsorption , Animals , Cattle , Gold/chemistry , Materials Testing/methods , Surface Plasmon Resonance/methods , Surface Properties
13.
Dermatol Surg ; 43(6): 775-783, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28394864

ABSTRACT

BACKGROUND: The implications of electrosurgical instrument use in patients with cochlear implants (CIs) are becoming increasingly relevant for dermatologic surgeons as the number of implanted CI devices continues to grow. The literature, however, fails to provide clear recommendations for appropriate treatment of these patients. OBJECTIVE: To systematically consolidate and critique the current literature regarding electrosurgical instrument use in patients with CI, to determine implications of various electrosurgical devices and settings on CI function and health of cochlear tissues, and to devise recommendations for appropriate use. MATERIALS AND METHODS: The manuscript was created based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. A broad search of PubMed, Access Medicine, Clinical Key, Ovid, Scopus, the Cochrane Library, and Web of Science was performed using key words such as CI, electrosurgery, and/or electrosurgical device. Criteria for inclusion included being written in English language and institutional access to manuscript. All years were included. Additional references were obtained from personal communication with CI manufacturers. Study biases were assessed through evaluation of funding and/or sponsoring agencies for included studies. RESULTS: The authors' search yielded a total of 8 studies, 5 of which were a level of evidence 5, 2 of which were level of evidence 4, and 1 of which was a level of evidence 3. The remaining study was relegated only to device testing. These studies were complicated by inaccurate terminology and inconsistent recommendations. CONCLUSION: The body of evidence evaluating electrosurgical instrument use in patients with CI is severely limited in number and quality. Thus, vague and inconsistent recommendations have emerged that place patients at risk of serious and costly adverse effects. In light of this, the authors suggest use of the most conservative recommendations available for electrosurgical instrument use in patients with CI.


Subject(s)
Cochlear Implants , Electrosurgery/instrumentation , Cochlear Implants/adverse effects , Humans , Postoperative Complications/etiology , Postoperative Complications/prevention & control , Practice Guidelines as Topic , Safety
14.
Curr Treat Options Oncol ; 17(12): 60, 2016 12.
Article in English | MEDLINE | ID: mdl-27766546

ABSTRACT

OPINION STATEMENT: Skin cancer is the most common of human cancers and outnumbers all other types of cancer combined in the USA by over threefold. The majority of non-melanoma skin cancers are easily treated with surgery or locally destructive techniques performed under local anesthesia in the cost-effective outpatient setting. However, there is a subset of "high-risk" cases that prove challenging in terms of morbidity, mortality, adjuvant treatment required, as well as overall cost to the health care system. In our opinion, the term "high risk" when applied to skin cancer can mean one of three things: a high-risk tumor with aggressive histologic and/or clinical features with an elevated risk for local recurrence or regional/distant metastasis, a high-risk patient with the ongoing development of multiple skin cancers, and a high-risk patient based on immunosuppression. We have recently proposed classifying NMSC as a chronic disease in a certain subset of patients. Although no consensus definition exists for a chronic disease in medicine, there are three components that are present in most definitions: duration of at least 1 year, need for ongoing medical care, and functional impairment and/or alteration of activities of daily living (ADLs) and quality of life (QOL). Immunosuppression can refer to exogenous (organ or stem cell transplant patients,) or endogenous (HIV, leukemia, lymphoma, genodermatoses with DNA mismatch repair problems or other immunosuppression) causes. These patients are at risk for high-risk tumors and/or the development of multiple tumors.


Subject(s)
Skin Neoplasms/diagnosis , Skin Neoplasms/therapy , Animals , Combined Modality Therapy/economics , Combined Modality Therapy/methods , Cost-Benefit Analysis , Disease Management , Humans , Retreatment , Skin Neoplasms/mortality , Treatment Outcome
15.
Oncotarget ; 7(45): 73147-73159, 2016 Nov 08.
Article in English | MEDLINE | ID: mdl-27705905

ABSTRACT

Adipocytes promote cancer progression and impair treatment, and have been shown to protect acute lymphoblastic leukemia (ALL) cells from chemotherapies. Here we investigate whether this protection is mediated by changes in oxidative stress. Co-culture experiments showed that adipocytes protect ALL cells from oxidative stress induced by drugs or irradiation. We demonstrated that ALL cells induce intracellular ROS and an oxidative stress response in adipocytes. This adipocyte oxidative stress response leads to the secretion of soluble factors which protect ALL cells from daunorubicin (DNR). Collectively, our investigation shows that ALL cells elicit an oxidative stress response in adipocytes, leading to adipocyte protection of ALL cells against DNR.


Subject(s)
Adipocytes/metabolism , Antibiotics, Antineoplastic/pharmacology , Daunorubicin/pharmacology , Drug Resistance, Neoplasm , Leukemia/metabolism , Oxidative Stress , 3T3-L1 Cells , Animals , Antioxidants/pharmacology , Cell Death/drug effects , Cell Death/genetics , Cell Line, Tumor , Drug Resistance, Neoplasm/genetics , Gene Expression Profiling , Glutathione/metabolism , Humans , Leukemia/drug therapy , Leukemia/genetics , Mice , Oxidative Stress/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Reactive Oxygen Species
16.
Dermatol Online J ; 22(6)2016 Jun 15.
Article in English | MEDLINE | ID: mdl-27617599

ABSTRACT

Cryptococcus neoformans is a common fungus found throughout the environment that causes opportunistic disease in immunocompromised individuals. Infection of humans with C neoformans usually manifests as lung disease through inhalation of spores or meningoencephalitis by involvement of the central nervous system. Rarely, dissemination in the form of cutaneous lesions can occur in individuals with long term immunosuppression. We present a patient with C. neoformans manifesting as cellulitis with focal segmental glomerulosclerosis treated with corticosteroids. Because of the mortality associated with disseminated cryptococcosis, early identification, especially of atypical cutaneous presentations is critical from a dermatological perspective.


Subject(s)
Cellulitis/etiology , Cryptococcosis/etiology , Fungemia/etiology , Glomerulosclerosis, Focal Segmental/drug therapy , Immunocompromised Host , Immunosuppressive Agents/adverse effects , Leg Dermatoses/etiology , Amphotericin B/therapeutic use , Antifungal Agents/therapeutic use , Cellulitis/drug therapy , Cellulitis/immunology , Cryptococcosis/drug therapy , Cryptococcosis/immunology , Cryptococcus neoformans , Cyclosporine/adverse effects , Fluconazole/therapeutic use , Flucytosine/therapeutic use , Fungemia/diagnosis , Fungemia/drug therapy , Fungemia/immunology , Humans , Leg Dermatoses/drug therapy , Leg Dermatoses/immunology , Leg Dermatoses/pathology , Male , Middle Aged , Prednisone/adverse effects , Skin/pathology
17.
Sci Rep ; 6: 24840, 2016 04 25.
Article in English | MEDLINE | ID: mdl-27108562

ABSTRACT

Carbon materials and nanomaterials are of great interest for biological applications such as implantable devices and nanoparticle vectors, however, to realize their potential it is critical to control formation and composition of the protein corona in biological media. In this work, protein adsorption studies were carried out at carbon surfaces functionalized with aryldiazonium layers bearing mono- and di-saccharide glycosides. Surface IR reflectance absorption spectroscopy and quartz crystal microbalance were used to study adsorption of albumin, lysozyme and fibrinogen. Protein adsorption was found to decrease by 30-90% with respect to bare carbon surfaces; notably, enhanced rejection was observed in the case of the tested di-saccharide vs. simple mono-saccharides for near-physiological protein concentration values. ζ-potential measurements revealed that aryldiazonium chemistry results in the immobilization of phenylglycosides without a change in surface charge density, which is known to be important for protein adsorption. Multisolvent contact angle measurements were used to calculate surface free energy and acid-base polar components of bare and modified surfaces based on the van Oss-Chaudhury-Good model: results indicate that protein resistance in these phenylglycoside layers correlates positively with wetting behavior and Lewis basicity.


Subject(s)
Diazonium Compounds/chemistry , Nanostructures/chemistry , Polysaccharides/chemistry , Prostheses and Implants/statistics & numerical data , Proteins/metabolism , Adsorption , Carbon/chemistry , Models, Chemical , Polysaccharides/metabolism , Proteins/chemistry , Surface Properties
18.
Obesity (Silver Spring) ; 21(7): 1380-8, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23754826

ABSTRACT

OBJECTIVE: Macrophages which infiltrate adipose tissue and secrete proinflammatory cytokines may be responsible for obesity-induced insulin resistance. However, the reason why macrophages migrate into adipose tissue and become activated remains unknown though some studies suggest that this may be regulated by T and B lymphocytes. In this study, it has been tested whether T and B lymphocytes and natural killer (NK) cells were necessary for the obesity-induced activation of macrophages in adipose tissue. DESIGN AND METHODS: NOD/SCID/IL2-receptor gamma-chain knockout (NSG) mice, which lack mature T and B lymphocytes and NK cells, were made obese by selectively reducing litters and weaning onto a high-fat diet. Mice were then maintained on the diet for 10-11 weeks. RESULTS: Adipose tissue from obese NSG mice had more activated macrophages than nonobese mice. These macrophages were found in "crown-like structures" surrounding adipocytes, and expressed higher levels of the inflammatory cytokine TNF-α. However, obesity did not impair glucose tolerance in the NSG mice. CONCLUSIONS: These studies demonstrated that T and B lymphocytes and NK cells are not necessary for adipose tissue macrophage activation in obese mice. T and B lymphocytes and/or NK cells may be necessary for the development of obesity-induced impaired glucose tolerance.


Subject(s)
Adipose Tissue/cytology , B-Lymphocytes/metabolism , Killer Cells, Natural/metabolism , Macrophages/metabolism , T-Lymphocytes/metabolism , Adipocytes/metabolism , Animals , Body Composition , Diet, High-Fat , Female , Glucose Intolerance , Hormones/blood , Male , Mice , Mice, Inbred C57BL , Mice, Inbred NOD , Mice, Knockout , Mice, SCID , Obesity/metabolism , Tumor Necrosis Factor-alpha/blood
19.
Cancer Res ; 73(10): 2998-3006, 2013 May 15.
Article in English | MEDLINE | ID: mdl-23585457

ABSTRACT

Obesity is a significant risk factor for cancer. A link between obesity and a childhood cancer has been identified: obese children diagnosed with high-risk acute lymphoblastic leukemia (ALL) had a 50% greater risk of relapse than their lean counterparts. l-asparaginase (ASNase) is a first-line therapy for ALL that breaks down asparagine and glutamine, exploiting the fact that ALL cells are more dependent on these amino acids than other cells. In the present study, we investigated whether adipocytes, which produce significant quantities of glutamine, may counteract the effects of ASNase. In children being treated for high-risk ALL, obesity was not associated with altered plasma levels of asparagine or glutamine. However, glutamine synthetase was markedly increased in bone marrow adipocytes after induction chemotherapy. Obesity substantially impaired ASNase efficacy in mice transplanted with syngeneic ALL cells and, like in humans, without affecting plasma asparagine or glutamine levels. In coculture, adipocytes inhibited leukemic cell cytotoxicity induced by ASNase, and this protection was dependent on glutamine secretion. These findings suggest that adipocytes work in conjunction with other cells of the leukemia microenvironment to protect leukemia cells during ASNase treatment.


Subject(s)
Adipocytes/physiology , Asparaginase/pharmacology , Glutamine/metabolism , Leukemia/drug therapy , 3T3-L1 Cells , Animals , Humans , Leukemia/metabolism , Leukemia/pathology , Mesenchymal Stem Cells/physiology , Mice , Mice, Inbred C57BL , Obesity/complications , Obesity/metabolism , Tumor Microenvironment
20.
J Urol ; 186(4 Suppl): 1663-7, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21862079

ABSTRACT

PURPOSE: Robotic assisted laparoscopic pyeloplasty is an emerging, minimally invasive alternative to open pyeloplasty in children for ureteropelvic junction obstruction. The procedure is associated with smaller incisions and shorter hospital stays. To our knowledge previous outcome analyses have not included human capital calculations, especially regarding loss of parental workdays. We compared perioperative factors in patients who underwent robotic assisted laparoscopic and open pyeloplasty at a single institution, especially in regard to human capital changes, in an institutional cost analysis. MATERIALS AND METHODS: A total of 44 patients 2 years old or older from a single institution underwent robotic assisted (37) or open (7) pyeloplasty from 2008 to 2010. We retrospectively reviewed the charts to collect demographic and perioperative data. The human capital approach was used to calculate parental productivity losses. RESULTS: Patients who underwent robotic assisted laparoscopic pyeloplasty had a significantly shorter average hospital length of stay (1.6 vs 2.8 days, p <0.05). This correlated with an average savings of lost parental wages of $90.01 and hospitalization expenses of $612.80 per patient when excluding amortized robot costs. However, cost savings were not achieved by varying length of stay when amortized costs were included. CONCLUSIONS: Robotic assisted laparoscopic pyeloplasty in children is associated with human capital gains, eg decreased lost parental wages, and lower hospitalization expenses. Future comparative outcome analyses in children should include financial factors such as human capital loss, which can be especially important for families with young children.


Subject(s)
Cost of Illness , Kidney/surgery , Laparoscopy/methods , Robotics , Ureter/surgery , Ureteral Obstruction/surgery , Urologic Surgical Procedures/methods , Adolescent , Child , Child, Preschool , Costs and Cost Analysis , Female , Follow-Up Studies , Humans , Laparoscopy/economics , Length of Stay/economics , Male , Parents , Plastic Surgery Procedures/economics , Plastic Surgery Procedures/methods , Retrospective Studies , Socioeconomic Factors , United States , Ureteral Obstruction/economics , Urologic Surgical Procedures/economics , Young Adult
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