- Immunological evaluation of chitosan nanoparticles loaded with tetanus toxoid. [Journal Article]
- BLBratisl Lek Listy 2018; 119(2):71-74
- CONCLUSIONS: The quality and efficacy of toxoid‑loaded chitosan nanoparticles were reasonable. It enhanced the immune responses as much as aluminum hydroxide adjuvant does and thus may be a good alternative candidate (Tab. 1, Fig. 3, Ref. 16).
- Improving the Thermal Stability and Flame Retardancy of PP/IFR Composites by NiAl-Layered Double Hydroxide. [Journal Article]
- JNJ Nanosci Nanotechnol 2018 May 01; 18(5):3660-3665
- Nickel and aluminum layered double hydroxide (NiAl-LDH) was synthesized via co-precipitation and modified by sodium dodecyl sulfate (SDS), which was marked as NiAl-OLDH. The structure of NiAl-LDH was...
Nickel and aluminum layered double hydroxide (NiAl-LDH) was synthesized via co-precipitation and modified by sodium dodecyl sulfate (SDS), which was marked as NiAl-OLDH. The structure of NiAl-LDH was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In order to investigate the role of LDH on polymer/intumescent flame retardant (IFR) systems, polypropylene (PP)/IFR/NiAl-OLDH nanocomposites were prepared by melt intercalation. Thermal and flame retardant properties of PP/IFR/NiAl-OLDH nanocomposites were studied. The results indicated that incorporation of NiAl-OLDH in PP/IFR composites significantly improved the thermal stability, flame retardancy and smoke suppression properties. With the addition of 5 wt% NiAl-OLDH, PP/IFR/NiAl-OLDH nanocomposites obtained UL-94 V0 level and the LOI value reached 27.5%. Compared with those of PP/IFR, the peak heat release rate (PHRR), total heat release (THR) and peak smoke production rate (PSPR) values reduced 49%, 10%, and 63%, respectively, which were attributed to the barrier effect and excellent charring performance of NiAl-OLDH.
- Immune response to antigen adsorbed to aluminum hydroxide particles: Effects of co-adsorption of ALF or ALFQ adjuvant to the aluminum-antigen complex. [Journal Article]
- JCJ Control Release 2018 Feb 09; 275:12-19
- Aluminum salts have been used as vaccine adjuvants for >50 years, and they are currently present in at least 146 licensed vaccines worldwide. In this study we examined whether adsorption of Army Lipo...
Aluminum salts have been used as vaccine adjuvants for >50 years, and they are currently present in at least 146 licensed vaccines worldwide. In this study we examined whether adsorption of Army Liposome Formulation (ALF) to an aluminum salt that already has an antigen adsorbed to it might result in improved immune potency of the aluminum-adsorbed antigen. ALF is composed of a family of anionic liposome-based adjuvants, in which the liposomes contain synthetic phospholipids having dimyristoyl fatty acyl groups, cholesterol and monophosphoryl lipid A (MPLA). For certain candidate vaccines, ALF has been added to aluminum hydroxide (AH) gel as a second adjuvant to form ALFA. Here we show that different methods of preparation of ALF changed the physical structures of both ALF and ALFA. Liposomes containing the saponin QS21 (ALFQ) have also been mixed with AH to form ALFQA as an effective combination. In this study, we first adsorbed one of two different antigens to AH, either tetanus toxoid conjugated to 34 copies of a hapten (MorHap), which has been used in a candidate heroin vaccine, or gp140 protein derived from the envelope protein of HIV-1. We then co-adsorbed ALF or ALFQ to the AH to form ALFA or ALFQA. In each case, the immune potency of the antigen adsorbed to AH was greatly increased by co-adsorbing either ALF or ALFQ to the AH. Based on IgG subtype and cytokine analysis by ELISPOT, ALFA induced predominately a Th2-type response and ALFQ and ALFQA each induced more balanced Th1/Th2 responses.
- Comparison of different agitation methods for the removal of calcium hydroxide from the root canal: Scanning electron microscopy study. [Journal Article]
- JCJ Conserv Dent 2017 Nov-Dec; 20(6):439-444
- CONCLUSIONS: Laser improved the removal of calcium hydroxide in comparison with conventional techniques.
- Red mud carbonation using carbon dioxide: Effects of carbonate and calcium ions on goethite surface properties and settling. [Journal Article]
- JCJ Colloid Interface Sci 2018 Feb 03; 517:230-238
- Carbonation using CO2appears as an attractive solution for disposing of red mud suspensions, an aluminum industry hazardous waste since it also offers an option for CO2sequestration. Here we report t...
Carbonation using CO2appears as an attractive solution for disposing of red mud suspensions, an aluminum industry hazardous waste since it also offers an option for CO2sequestration. Here we report the novel findings that CO32-together with Ca2+can significantly affect the surface properties and settling of goethite, a major component of red mud. Specifically, their effects on the goethite surface chemistry, colloidal interaction forces and settling in alkaline solutions are investigated. The surface potential becomes more negative by the formation of carbonate inner-sphere complexes on goethite surface. It is consistent with the strong repulsion, decreased particle size and settling velocity with increased carbonate concentrations as measured by atomic force microscopy, particle size analysis, and particle settling. Adding Ca2+that forms outer-sphere complexes with pre-adsorbed carbonate changes goethite surface charge negligibly. Changing repulsion to the attraction between goethite surfaces by increasing calcium dosage indicates the surface bridging, in accordance with the increased settling velocity. The adverse effect of carbonate on goethite flocculation is probably due to its specific chemisorption and competition with flocculants. By forming outer-sphere complexes together with the flocculant-calcium bridging effect, calcium ions can eliminate the negative influence of carbonate and improve the flocculation of goethite particles. These findings contribute to a better understanding of goethite particle interaction with salt ions and flocculants in controlling the particle behavior in the handling processes, including the red mud carbonation.
- Cd sequestration by bacteria-aluminum hydroxide composites. [Journal Article]
- CChemosphere 2018 Jan 29; 198:75-82
- Microbe-associated aluminum (Al) hydroxides occur naturally in aquatic and geologic environments and they might play a crucial role in the sequestration of trace metals because these composite solids...
Microbe-associated aluminum (Al) hydroxides occur naturally in aquatic and geologic environments and they might play a crucial role in the sequestration of trace metals because these composite solids comprise both reactive mineral and organic surface, but how they do it still remains unknown. Here we replicate Al hydroxide organo-mineral composite formation in soil and sediments by synthesising composites using Pseudomonas putida cells, during coprecipitation with Al hydroxide. Morphological and ATR-FTIR analysis show closely attached nano-sized Al hydroxides on the bacterial surface. For composites dominated by either bacteria or Al hydroxide, an enhanced metal adsorption is observed on the composites than on pure Al hydroxide at pH < 6. Cd uptake by the mainly Al mineral composite is approximately additive, i.e., the sum of the end-member metal adsorptivities, whereas that on the mainly bacteria composite is non-additive. This non-additive sorption is not only due to the blockage of surface reactive sorption sites, but more importantly the changes of surface charge when bacteria and Al mineral are interacted. EXAFS results show that Cd is predominately sorbed as a bidentate corner-sharing complex on the amorphous Al hydroxide surface and a carboxyl-binding on the bacterial surface. This study has important implications for understanding both Al and trace metal cycling in microbe-rich geologic environments.
- The preparation and physico-chemical characterization of aluminum hydroxide/TLR7a, a novel vaccine adjuvant comprising a small molecule adsorbed to aluminum hydroxide. [Journal Article]
- JPJ Pharm Sci 2018 Feb 05
- Adjuvants are necessary to enable vaccine development against a significant number of challenging pathogens for which effective vaccines are not available . We engineered a novel small-molecule im...
Adjuvants are necessary to enable vaccine development against a significant number of challenging pathogens for which effective vaccines are not available . We engineered a novel small-molecule immune potentiator (SMIP), a benzonaphthyridine agonist targeting toll-like receptor 7 (TLR7), as a vaccine adjuvant. TLR7 agonist (TLR7a) was engineered to be adsorbed onto aluminum hydroxide (AlOH), and the resulting AlOH/TLR7a was evaluated as a vaccine adjuvant [2-6]. AlOH/TLR7a exploits the flexibility of AlOH formulations, has an application in many vaccine candidates, and induced good efficacy and safety profiles against all tested antigens (bacterial- and viral-derived protein antigens, toxoids, glycoconjugates, etc.) in many animal models, including non-human primates . In this paper, we describe the outcome of the physico-chemical characterization of AlOH/TLR7a. Reverse phase ultra-performance liquid chromatography (RP-UPLC), confocal microscopy, flow cytometry (FC), zeta potential (ZP) and phosphophilicity assays were used as tools to demonstrate the association of TLR7a to AlOH and to characterize this novel formulation. Raman spectroscopy, nuclear magnetic resonance and mass spectroscopy were also used to investigate the interaction between TLR7a and AlOH (data not shown). This pivotal work paved the way for AlOH/TLR7a to progress into the clinic for evaluation as an adjuvant platform for vaccines against challenging preventable diseases.
- Toll-Like Receptor 8 Agonist Strengthens the Protective Efficacy of ESAT-6 Immunization to Mycobacterium tuberculosis Infection. [Journal Article]
- FIFront Immunol 2017; 8:1972
- Accumulating evidence suggests important functions for human Toll-like receptor 8 in vivo in tuberculosis and autoimmune diseases. However, these studies are limited by the lack of specific agonists ...
Accumulating evidence suggests important functions for human Toll-like receptor 8 in vivo in tuberculosis and autoimmune diseases. However, these studies are limited by the lack of specific agonists and by the fact that the homology of TLR8 in human and mice is not sufficient to rely on mouse models. In this study, we examined the role of human TLR8 in the disease progression of experimental Mycobacterium tuberculosis (Mtb) infection, as well as the benefits provided by a TLR8 agonist against Mtb challenge in a human TLR8 transgenic mouse. We found that the expression of human TLR8 in C57BL/6 mice permits higher bacilli load in tissues. A vaccine formulated with ESAT-6, aluminum hydroxide, and TLR8 agonist provided protection against Mtb challenge, with a high percentage of CD44hiCD62Lhi TCM. Using ovalbumin as a model antigen, we demonstrated that the activation of TLR8 enhanced the innate and adaptive immune response, and provided a sustained TCM formation and Th1 type humoral response, which were mainly mediated by type I IFN signaling. Further research is required to optimize the vaccine formulation and seek optimal combinations of different TLR agonists, such as TLR4, for better adjuvanticity in this animal model.
- Turning the Old Adjuvant from Gel to Nanoparticles to Amplify CD8+ T Cell Responses. [Journal Article]
- ASAdv Sci (Weinh) 2018; 5(1):1700426
- Due to its safety and efficacy, aluminum hydroxide is used as an immune adjuvant in human vaccines for over 80 years. Being a Th2 stimulator, the classical gel-like adjuvant, however, fails to genera...
Due to its safety and efficacy, aluminum hydroxide is used as an immune adjuvant in human vaccines for over 80 years. Being a Th2 stimulator, the classical gel-like adjuvant, however, fails to generate CD8+ T cell responses, which are important for cancer vaccines. Here, aluminum hydroxide is turned from gel into nano-sized vaccine carriers AlO(OH)-polymer nanoparticles (APNs) to promote their lymphatic migration. After actively uptaken via scavenger receptor-A by antigen-presenting cells (APCs) resident in lymph nodes (LNs), APNs destabilize lysosomes resulting in efficient cytosolic delivery and cross-presentation of antigens. It is demonstrated that administration of APNs loaded with ovalbumin (OVA) and CpG led to the codelivery of both cargos into APCs in LNs, leading to their activation and subsequent adaptive immunity. A prime-boost strategy with low doses of OVA (1.5 µg) and CpG (0.45 µg) induces potent CD8+ T cell responses and dramatically prolongs the survival of B16-OVA tumor-bearing mice. More impressively, when using B16F10 lysates instead of OVA as antigen, substantial antitumor effects on B16F10 tumor model are observed by using APN-CpG. These results suggest the great potential of APNs as vaccine carriers that activate CD8+ T cell responses and the bright prospect of aluminum adjuvant in a nanoparticle formulation.
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- Effects of humic substances on Fe(II) sorption onto aluminum oxide and clay. [Journal Article]
- GTGeochem Trans 2018 Jan 25; 19(1):3
- We studied the effects of humic substances (HS) on the sorption of Fe(II) onto Al-oxide and clay sorbents at pH 7.5 with a combination of batch kinetic experiments and synchrotron Fe K-edge EXAFS ana...
We studied the effects of humic substances (HS) on the sorption of Fe(II) onto Al-oxide and clay sorbents at pH 7.5 with a combination of batch kinetic experiments and synchrotron Fe K-edge EXAFS analyses. Fe(II) sorption was monitored over the course of 4 months in anoxic clay and Al-oxide suspensions amended with variable HS types (humic acid, HA; or fulvic acid, FA) and levels (0, 1, and 4 wt%), and with differing Fe(II) and HS addition sequences (co-sorption and pre-coated experiments, where Fe(II) sorbate was added alongside and after HS addition, respectively). In the Al-oxide suspensions, the presence of HS slowed down the kinetics of Fe(II) sorption, but had limited, if any, effect on the equilibrium aqueous Fe(II) concentrations. EXAFS analyses revealed precipitation of Fe(II)-Al(III)-layered double hydroxide (LDH) phases as the main mode of Fe(II) sorption in both the HA-containing and HA-free systems. These results demonstrate that HS slow down Fe(II) precipitation in the Al-oxide suspensions, but do not affect the composition or stability of the secondary Fe(II)-Al(III)-LDH phases formed. Interference of HS with the precipitation of Fe(II)-Al(III)-LDH was attributed to the formation organo-Al complexes HS limiting the availability of Al for incorporation into secondary layered Fe(II)-hydroxides. In the clay systems, the presence of HA caused a change in the main Fe(II) sorption product from Fe(II)-Al(III)-LDH to a Fe(II)-phyllosilicate containing little structural Al. This was attributed to complexation of Al by HA, in combination with the presence of dissolved Si in the clay suspension enabling phyllosilicate precipitation. The change in Fe(II) precipitation mechanism did not affect the rate of Fe(II) sorption at the lower HA level, suggesting that the inhibition of Fe(II)-Al(III)-LDH formation in this system was countered by enhanced Fe(II)-phyllosilicate precipitation. Reduced rates of Fe(II) sorption at the higher HA level were attributed to surface masking or poisoning by HA of secondary Fe(II) mineral growth at or near the clay surface. Our results suggest that HS play an important role in controlling the kinetics and products of Fe(II) precipitation in reducing soils, with effects modulated by soil mineralogy, HS content, and HS properties. Further work is needed to assess the importance of layered Fe(II) hydroxides in natural reducing environments.