Synergistic photothermal ablative effects of functionalizing carbon nanotubes with a POSS-PCU nanocomposite polymer

ABSTRACT: BACKGROUND: The application of nanotechnology in biology and medicine represents a significant paradigm shift in the approach to the treatment of cancer. Evidence suggests that when exposed to near-infrared radiation (NIR), carbon nanotubes (CNTs) dissipate a substantial amount of heat energy. We have developed a novel nanocomposite polymer, polyhedral oligomeric silsesquioxane poly (carbonate-urea) urethane (POSS-PCU). POSS-PCU displays excellent biocompatibility and has been used in making artificial organs as well as protective coatings for medical devices. RESULTS: Functionalizing (or "coating") CNTs with POSS-PCU confers biocompatibility and increase the amount of heat energy generated, by enhancing dispersion. Here we demonstrate that POSS-PCU-functionalized multi-walled CNTs (MWNTs) act synergistically together when exposed to NIR to thermally ablate cancer cells. CONCLUSION: Given that POSS-PCU has already been used in human in first-in-man studies as trachea, lacrimal duct, bypass graft and other organs, our long-term goal is to take POSS-PCU coated CNTs to clinical studies to address the treatment of cancer by optimizing its therapeutic index and increasing its specificity via antibody conjugation. RESULTS: Functionalizing (or "coating") CNTs with POSS-PCU confers biocompatibility and increase the amount of heat energy generated, by enhancing dispersion. Here we demonstrate that POSS-PCU-functionalized MWNTs act synergistically together when exposed to NIR to thermally ablate cancer cells. CONCLUSION: Given that POSS-PCU has already been used in human in first-in-man studies as trachea, lacrimal duct, bypass graft and other organs, our long-term goal is to take POSS-PCU coated CNTs to clinical studies.     

Hydrogen adsorption capacities of multi-walled boron nitride nanotubes and nanotube arrays: a grand canonical Monte Carlo study

Hydrogen adsorption in multi-walled boron nitride nanotubes and their arrays was studied using grand canonical Monte Carlo simulation. The results show that hydrogen storage increases with tube diameter and the distance between the tubes in multi-walled boron nitride nanotube arrays. Also, triple-walled boron nitride nanotubes present the lowest level of hydrogen physisorption, double-walled boron nitride nanotubes adsorb hydrogen better when the diameter of the inner tube diameter is sufficiently large, and single-walled boron nitride nanotubes adsorb hydrogen well when the tube diameter is small enough. Boron nitride nanotube arrays adsorb hydrogen, but the percentage of adsorbed hydrogen (by weight) in boron nitride nanotube arrays is rather similar to that found in multi-walled boron nitride nanotubes. Also, when the Langmuir and Langmuir-Freundlich equations were fitted to the simulated data, it was found that multi-layer adsorptivity occurs more prominently as the number of walls and the tube diameter increase. However, in single-walled boron nitride nanotubes with a small diameter, the dominant mechanism is monolayer adsorptivity.     

Potential applications of sheep oocytes as affected by vitrification and in vitro aging

The present study was carried out to investigate how the interactions between aging, vitrification and post-warming interval affect the credibility of sheep MII-oocytes for in vitro fertilization (IVF), intracytoplasmic injection (ICSI), and parthenogenetic activation (PA). According to our results, aged oocytes had significantly higher rates of chromosome and spindle abnormalities compared to young oocytes. However after vitrification-warming, the total rates of these abnormalities were not significantly different between aged and young oocytes. Unvitrified-aged, and vitrified young and aged oocytes had comparable ultrastructural characteristics, whereas they were completely dissimilar in compared with unvitrified-young oocytes. Although mRNA abundance was reduced during vitrification-warming in both aged and young oocytes, the post-warming interval could improve the relative mRNA abundance. Aged oocytes had lower capacity for IVF and ICSI in compared with young oocytes, but had similar pattern for PA process. The vitrification process decreased developmental competence of both aged and young oocytes in compared with young ones, particularly when warmed oocytes were rested for 2 h before IVF, ICSI and PA. The results of the present study showed that in vitro aged oocytes had higher capacity to be used for parthenogenetic studies rather than IVF and ICSI. Furthermore, it was shown that vitrified oocytes had a time-dependent decline in quality and developmental potential. Notably, the speed of this decline was higher in vitrified-young oocytes, indicating that the vitrified oocytes do not require to be rested post warming. Conclusively, the results of this study can be useful in preserving in vitro aged oocytes to provide a valuable and easy access source of oocytes for research purposed studies.     

Effects of 5-HT1A and 5-HT2A receptor stimulation on temporal differentiation performance in the fixed-interval peak procedure

We examined the effects of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and 5-HT(2A/2C) receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) on performance on the fixed-interval peak procedure, and the sensitivity of these effects to 5-HT1A and 5-HT2A receptor antagonists (N-[2-(4-[2-methoxyphenyl]-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide [WAY-100635] and ketanserin). Rats were trained to press a lever for food reinforcement in 50 min sessions consisting of 32 trials in which the lever was continuously available, separated by 10 s inter-trial intervals. In 16 trials, reinforcement was delivered following the first response after 30 s had elapsed since trial onset (fixed-interval 30 s). In 16 randomly interposed (peak/probe) trials, reinforcement was omitted, and the lever remained in the operant chamber for 120 s. Response rate in probe trials was plotted against time from trial onset. Time to peak response rate (t(peak)) and the Weber fraction were derived from modified Gaussian curves fitted to each rat's data. 8-OH-DPAT (0.05 mg kg(-1)) reduced t(peak) and increased the Weber fraction; the effect on t(peak) was antagonized by WAY-100635 (0.1 mg kg(-1)). DOI (0.25 mg kg(-1)) also reduced t(peak) and increased the Weber fraction; the reduction of t(peak) was antagonized by ketanserin (2 mg kg(-1)). Stimulation of 5-HT1A and 5-HT2A receptors alters temporal differentiation in qualitatively similar ways.     

Lentiviral Expression of Rabies Virus Glycoprotein in the Rat Hippocampus Strengthens Synaptic Plasticity

Rabies virus (RABV) is a neurotropic virus exclusively infecting neurons in the central nervous system. RABV encodes five proteins. Among them, the viral glycoprotein (RVG) plays a key role in viral entry into neurons and rabies pathogenesis. It was shown that the nature of the C-terminus of the RABV G protein, which possesses a PDZ-binding motif (PBM), modulates the virulence of the RABV strain. The neuronal protein partners recruited by this PBM may alter host cell function. This study was conducted to investigate the effect of RVG on synaptic function in the hippocampal dentate gyrus (DG) of rat. Two μl (10⁸ T.U./ml) of the lentiviral vector containing RVG gene was injected into the DG of rat hippocampus. After 2 weeks, the rat’s brain was cross-sectioned and RVG-expressing cells were detected by fluorescent microscopy. Hippocampal synaptic activity of the infected rats was then examined by recording the local field potentials from DG after stimulation of the perforant pathway. Short-term synaptic plasticity was also assessed by double pulse stimulation. Expression of RVG in DG increased long-term potentiation population spikes (LTP-PS), whereas no facilitation of LTP-PS was found in neurons expressing δRVG (deleted PBM). Furthermore, RVG and δRVG strengthened paired-pulse facilitation. Heterosynaptic long-term depression (LTD) in the DG was significantly blocked in RVG-expressing group compared to the control group. This blockade was dependent to PBM motif as rats expressing δRVG in the DG-expressed LTD comparable to the RVG group. Our data demonstrate that RVG expression facilitates both short- and long-term synaptic plasticity in the DG indicating that it may involve both pre- and postsynaptic mechanisms to alter synaptic function. Further studies are needed to elucidate the underlying mechanisms.

     

Area of protection in S-LCA: human well-being or societal quality

The International Journal of Life Cycle Assessment - The set of stakeholders included in the social life cycle assessment (S-LCA) guideline (UNEP/SETAC 2009) could create confusion as to the target...     

Study of aldehyde oxidase-catalyzed metabolic pathway of phenanthridine using MCR-ALS method

Evaluation of metabolic pathways is one of the challenging areas in biological and pharmaceutical sciences. Phenanthridine oxidation to phenanthridinone is used commonly to study aldehyde oxidase activity. This reaction could pass through phenanthridine N-oxide intermediate. In the present study, the application of multivariate curve resolution, optimized by alternating least squares (MCR-ALS) to investigate this metabolic pathway has been described. The results obtained from MCR-ALS analysis along with those obtained from the use of potassium ferrocyanide method indicated that phenanthridine is directly oxidized to phenanthridinone by rat liver aldehyde oxidase without passing through phenanthridine N-oxide intermediate. It was also found that the later compound is not metabolized by this enzyme.     

Toll-like receptors (TLRs): An old family of immune receptors with a new face in cancer pathogenesis

In the dark path of tumorigenesis, the more carefully the cancer biology is studied, the more brilliant answers could be given to the countless questions about its orchestrating derivers. The identification of the correlation between Toll-like receptors (TLRs) and different processes involved in carcinogenesis was one of the single points of blinding light highlighting the interconnection between the immune system and cancer. TLRs are a wide family of single-pass membrane-spanning receptors that have developed through the evolution to recognize the structurally conserved molecules derived from microorganisms or damaged cells. But this is not everything about these receptors as they could orchestrate several downstream signalling pathways leading to the formation or suppression of cancer cells. The present review is tempted to provide a concise schematic about the biology and the characters of TLRs and also summarize the major findings of the regulatory role of TLRs and their associated signalling in the pathogenesis of human cancers.