Nanoparticles In Water Research Articles

Colloidal dispersions of cobalt ferrite nanoparticles in EMIM TFSI, propylene carbonate and their mixtures

Liquid thermocells are promising devices for the recovery of low-grade waste heat and its conversion into electricity. The present study proposes dispersing charged magnetic nanoparticles in liquids to improve thermoelectric conversion, due to their thermodiffusive and magnetic properties. Core@shell cobalt ferrite@maghemite nanoparticles (NPs) of various sizes with three different kinds of coatings are tested for dispersion in EMIM TFSI (ethyl-methylimidazolium bistriflimide), an ionic liquid (IL) of high electrical conductivity. Among the tested ligands, PAC6MIM±Br− (1-(6-hexylphosphonate) 3-methyl imidazolium bromide) emerges as the most efficient due to its phosphonic group. This ligand leads to dispersions of clusters of a few dozen NPs in water and a few NPs in EMIM TFSI. For improving both the viscosity and the electrical conductivity, dispersions in binary mixtures of propylene carbonate (PC), a polar medium, and EMIM-TFSI are further investigated with the sample based on NPs of ∼ 9 nm diameter. Through a pumping and heating procedure, stable dispersions are obtained with a subsequent reduction of the size of the NP clusters, down to 1 to 2 NPs in EMIM TFSI and a few NPs in PC and their binary mixtures. The mixture with an IL mole fraction ∼0.2–0.3 and maximal electrical conductivity is a promising candidate for further thermoelectric investigations.

Construction of Through‐Space Charge‐Transfer Nanoparticles for Facilely Realizing High‐Performance NIR‐II Cancer Phototheranostics

AbstractPhototheranostics with second near‐infrared (NIR‐II) emissions show great potential for disease diagnosis and imaging‐guided phototherapy owing to deep tissue penetration, high imaging resolution, and excellent tumor eradication. Recently, molecular conjugation engineering and J‐aggregation have been used to construct organic NIR‐II materials. However, these molecules generally have extensive conjugation and large molecular weight in the range of 700–1700 g mol−1, requiring complicated molecular design and synthesis. Herein, a NIR‐II emissive through‐space charge‐transfer (TSCT) nanoparticle (NP) using short‐conjugated donor‐acceptor (D‐A) molecules (TTP) is reported for high‐performance bioimaging and cancer phototheranostics. Owing to the short conjugation of the TTP molecule with a small molecular weight of only 518 g mol−1, the TTP monomer possesses visible absorption and first near‐infrared (NIR‐I) emission. Upon forming NPs in water, the efficient TSCT between TTP monomers leads to significantly red‐shifted absorption to the NIR‐I and emission to the NIR‐II region with a tail that extends to 1400 nm. TTP NPs are employed in NIR‐II in vivo blood‐vessel bioimaging and cancer phototheranostics successfully. This work introduces a facile strategy to construct NIR‐II emissive NPs based on short‐conjugated D‐A molecules for high‐performance biomedical applications.

Biocompatible Cobalt Oxide Nanoparticles for X-ray Fluorescence Microscopy.

The synthesis of water-soluble nanoparticles is a well-developed field for ferrite-based nanoparticles with the majority consisting of iron oxide or mixed metal iron oxide nanoparticles. However, the synthesis of non-agglomerated non-ferrite metal/metal oxide NPs is not as well established. The synthesis and characterization of uniform 20 nm, biologically compatible cobalt oxide (CoO) nanoparticles (NPs) is described. These nanoparticles have two principle components: 1) a CoO core of suitable size to contain enough cobalt atoms to be visualized by X-ray fluorescence microscopy (XFM) and 2) a robust coating that inhibits NP aggregation as well as renders them water-soluble and biocompatible (i.e. stealth coatings). Stable cobalt oxide NPs are obtained with octadecyl amine coatings as reported by Bhattacharjee. Two strategies for solubilizing these NPs in water were investigated with varying degrees of success. Exchanging the octadecyl amine coating for a nitrodopamine anchored PEG coating yielded the desired water-soluble NPs but in very low yield. Alternately, leaving the octadecyl amine coating on the NP and interdigitating this with a maleic anhydride-vinyl copolymer with different hydrophobic sidechains followed by opening the maleic anhydride ring with amine substituted PEG polymers (the water solubilizing component), yielded the desired water soluble NPS were obtained in good yield. Characterization data for the nanoparticles and the components of the coatings required for bioorthogonal reactions to ligate them with biotargeting agents are also described.

Molecular Modeling of the Fluorination Effect on the Penetration of Nanoparticles across Lipid Bilayers.

The fluorinated decorations have recently been widely used in many biomedical applications. However, the potential mechanism of the fluorination effect on the cellular delivery of nanoparticles (NPs) still remains elusive. In this work, we systemically explore the penetration of a perfluoro-octanethiol-coated gold NP (PF-Au NP) and, for comparison, an octanethiol-coated gold NP (OT-Au NP) across lipid bilayers. We also investigated the effect of these two types of NPs on the properties of lipid bilayers. Our findings indicate that the lipid type and the surface tension of the lipid bilayer significantly impact the penetration capabilities of the fluorinated gold NP. By examining the distribution of ligands on the surface of the two types of NPs in water and during the penetration process, we unveil their distinct penetration characteristics. Specifically, the PF-Au NP exhibits amphiphobic behavior (both hydrophobic and lipophobic), while the OT-Au NP exhibits solely hydrophobic characteristics. Finally, we observe that the penetration capabilities can be increased by adjusting the degree of fluorination of the ligands on the NP surface. Overall, this study provides useful physical insights into the unique properties of the fluorinated decorations in NP permeation.

Red fluorescent BODIPY-based nanoparticles for targeted cancer imaging-guided photodynamic therapy.

Imaging-guided diagnosis and treatment of cancer hold potential to significantly improve therapeutic accuracies and efficacies. Central to this theragnostic approach has been the use of multicomponent-based multimodal nanoparticles (NPs). Apart from this conventional approach, here we propose a design strategy for the simple and straightforward formulation of NPs based on boron dipyrromethene (BODIPY) derivatives, LaB-X (X = H, Et, and Br). Specifically, the conjugation of lactose to the inherently hydrophobic BODIPY promoted the formation of LaB-X NPs in water. Furthermore, the BODIPY backbone was subjected to distyrylation, dibromination, and diethylation to tailor the optical window and the balance between fluorescence and singlet oxygen generation capabilities. We demonstrate that while the photoinduced anticancer activities of LaB-H and LaB-Et NPs were trivial, LaB-Br NPs effectively induced the apoptotic death of hepatocellular carcinoma cells under red light irradiation while allowing fluorescence cell imaging in the phototherapeutic window. This dual fluorescence photosensitizing activity of LaB-Br NPs could be switched off and on, so that both fluorescence and singlet oxygen generation were paused during NP formation in an aqueous solution, while both processes resumed after cellular uptake, likely due to NP disassembly.

Lifetime-based luminescence thermometry from Yb3+/Er3+ codoped nanoparticles suspended in water

The thermal sensing capabilities of Y2O3:Yb3+/Er3+ codoped nanoparticles (NPs) have been extensively studied in recent years for remote luminescent thermometry. However, the use of intensity-based methods for temperature sensing in biological media may be hindered by tissue-induced spectral artifacts, such as light scattering and absorption. To explore alternatives to intensity-based techniques towards bio-sensing applications, we present lifetime-based nanothermometry experiments conducted with a suspension of Y2O3:Yb3+/Er3+ NPs in water. Time-resolved measurements were performed regarding the luminescence from the 2H11/2 (525 nm), 4S3/2 (545 nm), and 4F9/2 (660 nm) excited states of Er3+ for temperatures ranging from 298 K to 338 K. A simplified effective-phonon model was proposed to explain the measured decrease in lifetimes with increasing temperature. The thermometers presented relative sensitivities SR of 0.31% K−1, 0.34% K−1 at 310 K for the luminescence bands centered at 525 nm, 545 nm, respectively, and a best SR value of 0.50% K−1 at 310 K for luminescence at 660 nm. The results obtained with the red-emitting band under green excitation demonstrate that the lifetime-based nanothermometers can present high SR if compared to intensity-based sensors, reinforcing their potential for applications in aqueous and/or biological media.

Interfacial Cu2O enables the unanticipated boosting activity of arc-converted graphitic chain mail encapsulated Cu nanocatalysts

Encapsulation of Cu nanoparticles by carbon chain mail is a promising approach to extend the service endurance. However, the diffusion of oxygen across the surfaces and interfaces of Cu nanoparticles (NPs) may induce obvious changes to their surface compositions, thereby dramatically altering catalytic properties. Here we reported an unanticipated boosting catalytic activity of graphitic chain mail-encapsulated Cu nanocatalysts (1.3- to 6.8-fold enhancement from initial 1.6–13.4 s−1g−1 to stable 6.6–21.5 s−1g−1) for the reduction of 4-nitrophenol by simply immersing these NPs in water for 10 days without any further treatment. The graphitic shells were arc-converted from sixteen types of biomass residuals and polymeric wastes. The rising catalytic activity was attributed to the temporal formation of Cu2O at the interface of Cu core and graphite shell, which was derived from the diffusion of dissolved oxygen across the defective graphitic chain mail. The increment of catalytic activity was linearly related with the rising content of Cu2O. The monotonous relations of initial and enhanced activities with shell thickness and interfacial composition of NPs were also well established. This work provides a new insight into the interfacial manipulation of core/shell nanocatalysts, and paves a versatile path for the high value-added utilization of carbon wastes.

Small anticancer drug release by light: Photochemical internalization of porphyrin-β-cyclodextrin nanoparticles

Aiming to engineer simple, neutral, strongly amphiphilic photoactive nanoparticles (NPs) to specifically target cancer cell lysosomes for drug transport and light-controlled release, new conjugates of β-cyclodextrin with highly hydrophobic triphenylporphyrin bearing different alkyl chains, were synthesized. Although differently sized, all conjugates self-assemble into ~60 nm NPs in water and display similar photoactivity. The NPs target selectively the lysosomes of breast adenocarcinoma MCF-7 cells, embedding in vesicular membranes, as experiments with model liposomes indicate. Either empty or drug-loaded, the NPs lack dark toxicity for 48 h. They bind with differently structured anticancer drugs tamoxifen and gemcitabine as its N-adamantyl derivative. Red light irradiation of cells incubated with drug-loaded NPs results in major reduction of viability (>85 %) for 48 h displaying significant synergy of photo-chemotoxicity, as opposed to empty NPs, and to loaded non-irradiated NPs, in manifestation of photochemical internalization (PCI). Our approach expands the field of PCI into different small molecule chemotherapeutics.

All Organic Aqueous Processable Piezo‐Phototronic Ink for Strain Modulated Photoresponse

AbstractIn this study, poly(vinylidene fluoride) (PVDF) nanoparticles (NPs) are fabricated with the preferred electroactive δ‐phase due to the interfacial crystallization at the ternary phase system, i.e., PVDF‐DMF‐water at ambient conditions. Further, the surfaces of PVDF NPs are modified with in situ copolymerized polydopamine‐polyethylenimine (PDA‐PEI) to ensure the well dispersion of poorly dispersive PVDF NPs in water. The piezoresponse force microscopy (PFM) confirms the piezo‐ and ferro‐electric capabilities of PDA‐PEI coated PVDF NPs (i.e., PVDF@f Ink) with an associated phase reversal of Δϕ ≈ 180° upon the application of a very low DC bias voltage that indicates their applicability in low power devices. Additionally, fabricated flexible piezoelectric nanogenerator (f‐PNG) with PVDF@f Ink shows a promising electrical output as a mechanical energy harvester. It also promises the physiological signals detection abilities due to superior mechanoacoustic behavior. Furthermore, f‐PNG has shown excellent photo‐detection and piezo‐phototronic properties. The fast photoresponse of 0.43 s, responsivity of 24 µA W−1, and specific detectivity ≈1.4 × 1010 Jones, promises the ideal choice for the optoelectronic devices. Thus, it is expected that the PDA‐PEI coated δ‐phase comprising PVDF NPs can be utilized as a piezoelectric ink for flexible optoelectronic devices.

Beyond single-crystal surfaces: The GAL21 water/metal force field.

Solvent effects are notoriously difficult to describe for metallic nanoparticles (NPs). Here, we introduce GAL21 which is the first pairwise additive force field that is specifically designed to modulate the near chemisorption energy of water as a function of the coordination numbers of the metallic atoms. We find a quadratic dependence to be most suitable for capturing the dependence of the adsorption energy of water on the generalized coordination number (GCN) of the metal atoms. GAL21 has been fitted against DFT adsorption energies for Cu, Ag, Au, Ni, Pd, Pt, and Co on 500 configurations and validated on about 3000 configurations for each metal, constructed on five surfaces with GCNs varying from 2.5 to 11.25. Depending on the metals, the root mean square deviation is found between 0.7kcal mol-1 (Au) to 1.6kcal mol-1 (Ni). Using GAL21, as implemented in the open-source code CP2K, we then evaluate the solvation energy of Au55 and Pt55 NPs in water using thermodynamic integration. The solvation free energy is found to be larger for Pt than for Au and systematically larger than 200kcal mol-1, demonstrating the large impact of solvent on the surface energetics of NPs. Still, given that the amorphous NPs are both, the most stable and the most solvated ones, we do not predict a change in the preferred morphology between the gas-phase and in water. Finally, based on a linear regression on three sizes of NPs (from 38 to 147), the solvation energy for Au and Pt surface atoms is found to be -5.2 and -9.9kcal mol-1, respectively.

Overview on Green Titanium Nanoparticles Based on Plants: Synthesis, Potential Applications and Eco-Friendly Approach.

Nanotechnology is generating a lot of buzz across the world, because of its fascinating applications in various disciplines. Due to recent breakthroughs in the nanotechnology sector, metal oxide nanoparticles (NPs) have found a number of uses in a variety of industrial, medicinal, and environmental fields. Titanium dioxide nanoparticles (TiO2 NPs) have been widely utilized in everyday life and maybe manufactured using a variety of physical, chemical, and green approaches. Green synthesis is a non-toxic, cost-effective, and environmentally responsible way to make NPs. The green, chemical, physical, and biological production of TiO2 NPs has received a lot of attention, and these NPs may be analysed using high-tech tools. The current study contains extensive information on the comparative synthesis of TiO2 NPs with various properties and their wide range of applications. Because of the decreased usage of precursors, time-effectiveness, and energy efficiency during green synthesis processes, green approaches have been proved to be more efficient than chemical synthesis methods for TiO2 NPs production. The relevance of green manufacturing of TiO2 nanoparticles using plant extract is discussed in this review study. Recent breakthroughs in the manufacture of TiO2 nanoparticles, from plants have shown promise in various scientific and technological domains. The physical features, crystal properties, antibacterial, anticancer, and photo catalytic activity of TiO2 are summarised in this review. The many components of the green synthesis strategy for TiO2 NPs and medicinal applications were discussed. Nanoparticle stability and toxicity, as well as surface engineering strategies for ensuring biocompatibility, are also reviewed. Furthermore, the obstacles and concerns surrounding using green product TiO2 NPs in water and wastewater treatment were explored. Hence, this review article condenses TiO2 NPs physicochemical properties, green synthesis, toxic exposure, biodistribution, and applications.

Overview on Green Titanium Nanoparticles Based on Plants: Synthesis, Potential Applications and Eco-Friendly Approach.

Nanotechnology is generating a lot of buzz across the world, because of its fascinating applications in various disciplines. Due to recent breakthroughs in the nanotechnology sector, metal oxide nanoparticles (NPs) have found a number of uses in a variety of industrial, medicinal, and environmental fields. Titanium dioxide nanoparticles (TiO2 NPs) have been widely utilized in everyday life and maybe manufactured using a variety of physical, chemical, and green approaches. Green synthesis is a non-toxic, cost-effective, and environmentally responsible way to make NPs. The green, chemical, physical, and biological production of TiO2 NPs has received a lot of attention, and these NPs may be analysed using high-tech tools. The current study contains extensive information on the comparative synthesis of TiO2 NPs with various properties and their wide range of applications. Because of the decreased usage of precursors, time-effectiveness, and energy efficiency during green synthesis processes, green approaches have been proved to be more efficient than chemical synthesis methods for TiO2 NPs production. The relevance of green manufacturing of TiO2 nanoparticles using plant extract is discussed in this review study. Recent breakthroughs in the manufacture of TiO2 nanoparticles, from plants have shown promise in various scientific and technological domains. The physical features, crystal properties, antibacterial, anticancer, and photo catalytic activity of TiO2 are summarised in this review. The many components of the green synthesis strategy for TiO2 NPs and medicinal applications were discussed. Nanoparticle stability and toxicity, as well as surface engineering strategies for ensuring biocompatibility, are also reviewed. Furthermore, the obstacles and concerns surrounding using green product TiO2 NPs in water and wastewater treatment were explored. Hence, this review article condenses TiO2 NPs physicochemical properties, green synthesis, toxic exposure, biodistribution, and applications.

Simulation and visualization of nano SiO2 - water and decanoic acid-modified nano CeO2 - cyclohexane dispersions under a centrifugal field

This work examines simulation and visualization methods for describing settling characteristics of nanoparticles (NPs) of (60, 100 or 200) nm SiO2 NPs in water and 8.7 nm decanoic acid-modified CeO2 (C10CeO2) NPs in cyclohexane measured experimentally under centrifugal fields. Analytical centrifugation of NP dispersions at relative centrifugal fields (RCF) of up to 2325 g at 20 °C was used to obtain space and time-resolved concentration profiles (STCP) along with supernatant/suspension phase interface height (IH) changes with time. A simplified advection-diffusion (sAdDf) model (Antonopoulou et al., Physics of Fluids 30 (2018) https://doi.org/10.1063/1.5010735) was modified for polydisperse systems by using: (i) Gaussian (G) average of two single diameter simulations, (ii) effective axial dispersion coefficient (EADC) to replace diffusion coefficient (D) with (Dax=D/k) and (iii) use of experimental maximum packing volume fraction (Maxpack). For SiO2 systems in water, the model with effective diameter (de) was able to quantitatively represent IH changes with time for 200 nm SiO2 NPs (de=200 nm), 100 nm SiO2 NPs (de=110 nm) and 60 nm SiO2 NPs (de=90 nm), where smaller particle sizes required larger de. STCP of SiO2 NP systems could be represented quantitatively with G or AD modifications for 200 nm SiO2 NP systems, but simulations became qualitative as particle size decreased. STCP of C10CeO2 NPs in cyclohexane did not show clear IH boundaries as each profile seemed to show continuous hindered settling of collected particles. The model with G or AD modification of were able to provide qualitative representation of the STCP. Remarkably, Maxpack (=0.359) modification with the model allowed quantitative representation of the apparent IH for 7 wt% (1.89 vol%) C10CeO2 NPs in cyclohexane. Transmittograms of the STCP show that the settling characteristics of C10CeO2 NPs in cyclohexane are fuzzy without clear boundaries, which indicates settling is probably dictated by smaller NPs and their solvation shells that interact in a collective manner to cause long-range (μm order) interactions.

Betaine-based deep eutectic solvents mediated synthesis of zinc oxide nanoparticles at low temperature

Deep eutectic solvents (DES) are gaining popularity as a potential substitute for ionic liquids because of their lower cost and biodegradability. Betaine and phenol with melting points ∼300 °C and ∼43 °C, respectively, combine with a molar ratio of 1:2 to form a liquid at room temperature with a eutectic melting point of ∼20 °C. ZnO nanoparticles (NPs) were synthesized by using an eco-friendly and green synthesis method utilizing betaine-based DES at low temperature ∼80 °C for 2 h. X-ray diffraction analysis confirms the highly crystalline and single-phase formation of ZnO NPs with hexagonal-Wurtzite phase structure. The surface morphology of the ZnO NPs confirmed using scanning electron microscopic images revealing the mostly spherical in shape and some n-pointed stars and transmission electron microscopy images confirms that NPs are sub-100 nm in range. Also, energy dispersive X-ray results confirm the elemental composition of Zn K (∼8.6 keV) and O K (0.52 keV) to be ∼88.5 ± 1.7% and 11.5 ± 1.3%, respectively. Fourier transform infrared spectroscopy confirms the bands at 565 and 410 cm−1 is assigned to asymmetric stretching and bending vibrations of the Zn–O tetrahedron. Thermogravimetric analysis verified the thermal stability with phase purity, resulting in the formation of the single-phase crystalline ZnO NPs. UV–Vis absorption study confirms the bandgap of ∼3.1 eV. The high stability and dispersion of NPs in water confirms the interaction of DES molecules on the surface of the NPs with water. ZnO NPs incorporated in PVA thin films show strong UV–Vis absorption confirming use of these transparent thin films for UV-shielding applications. As far as we know, this study is unique, green, eco-friendly and cost-effective in that the authors were able to synthesize ZnO NPs from betaine-based DES.

Aggregation of Fe2O3 nanoparticle in the presence of organophosphate esters (OPEs).

Aggregation is a key process for determining the environmental behavior and impact of a nanoparticle (NP). Since organophosphate esters (OPEs), which are recognized as emerging contaminants, are distributed widely in the natural aquatic environment, they may contribute to interacting with NPs and ultimately influence their transport and fate. Here, we investigated two typical organophosphate esters OPEs on aggregation the Fe2O3 NP in aquatic environments. The results showed that both tri-ethylhexyl phosphate (TEHP) and tris (chloroisopropyl) phosphate (TCPP) improved the colloidal stability of Fe2O3 NP in artificial water and environmental matrices. TEHP exhibited an obvious effect than TCPP on the Zeta potential and aggregation rates of Fe2O3 NP in artificial water. In the presence of electrolyte, 10 mg/L TCPP and TEHP increased the critical coagulation concentration (CCC) by 3.6 times and 17.4 times, respectively. Compared with pore-water, the aggregation rates of Fe2O3 NP in river water were slightly higher than those in pore-water, which can be attributed to the higher DOC in pore-water. We suggested that the high hydrophobicity and molecular weight of OPEs were considered important factors against the aggregation of Fe2O3 NP in water. Greater surface charge and steric hindrance originating from TCPP and TEHP dominated the colloidal stability of Fe2O3 NP.

A review of recent and emerging antimicrobial nanomaterials in wastewater treatment applications

In this paper, we present a critical review on antimicrobial nanomaterials with demonstrated potential for application as a disinfection technology in wastewater treatment. Studies involving fabrication and testing of antimicrobial nanomaterials for wastewater treatment were gathered, critically reviewed, and analyzed. Our review shows that there are only a few eligible candidate nanoparticles (NPs) (metal and metal oxide) that can adequately serve as an antimicrobial agent. Nanosilver (nAg) was the most studied and moderately understood metal NPs with proven antimicrobial activity followed by ZnO (among antimicrobial metal oxide NPs) which outperformed titania (in the absence of light) in efficacy due to its better solubility in aqueous condition. The direction of future work was found to be in the development of antimicrobial nanocomposites, since they provide more stability for antimicrobial metal and metal oxides NPs in water, thereby increasing their activity. This review will serve as an updated survey, yet touching also the fundamentals of the antimicrobial activity, with vital information for researchers planning to embark on the development of superior antimicrobial nanomaterials for wastewater treatment applications.

Surface functionalization of cellulose fibers via aza-Michael addition for CO2-assisted water remediation

The remediation of water that polluted by organic dyes and nanoparticles (NPs) remains a great challenge. However, second pollution of solid waste may produce if the adsorbents are not degradable or recyclable. The stimuli-responsive materials were regarded to be able to resolve this problem by reversible adsorption-desorption under stimuli. Here in this work, the surface of cellulose fibers was modified with CO2-responsive molecules through a simple esterification followed by an aza-Michael addition reaction. The chemical structure was confirmed with Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), x-ray diffractometer (XRD) and thermal analysis. The gas-responsiveness was demonstrated by monitoring of the pH, conductivity and surface zeta potential. Anionic dyes and negative charged NPs in water can be selectively and reversibly captured by the CO2-responsive surface on cellulose fibers, suggesting the inexpensive, readily available and smart cellulose fibers may find great potential in water remediation.

Effect of Modified Fe3O4 Magnetic NPs on the Absorption Capacity of CO2 in Water, Wettability Alteration of Carbonate Rock Surface, and Water–Oil Interfacial Tension for Oilfield Applications

Implementation of carbonated water in the enhanced oil recovery (EOR) process for oil reservoirs by increasing the carbon dioxide (CO2) content in water causes interfacial tension (IFT) between oil and carbonated water to decline, thereby increasing the areal sweep efficiency as well as oil recovery. For this reason, the main purpose of this research was to examine the effect of using polymer-based Fe3O4 nanoparticles (NPs) on the amount of CO2 absorption in distilled water under different conditions (pressure: 20–40 bar, temperature: 35–60 °C, concentration of NPs: 0.01 to 0.14 wt %). To this end, two experimental setups were employed to measure the amount of CO2 absorption in water in the presence of bare Fe3O4 NPs, Fe3O4 NPs coated by poly(vinyl alcohol) (FPVA), and Fe3O4 NPs coated by polyacrylamide (FPAM) synthesized by the co-precipitation technique, and the IFT between oil and carbonated water. The results revealed that the presence of FPVA and FPAM NPs in water causes the amount of CO2 absorption to enhance up to 20.2 and 23.3%, respectively, as compared to water alone at 40 bar. Subsequently, to evaluate the potential of the synthesized NPs in reducing capillary pressure in oil reservoirs, the interfacial tension (IFT) between carbonated water containing each of these three NPs alone with the concentration of 0.01 wt % (Fe3O4, FPVA, FPAM NPs) and oil at various pressures and temperatures up to 80 bar and 80 °C, respectively, was measured. The results demonstrated that a maximum reduction in the IFT between oil and carbonated water in the presence of modified Fe3O4 NPs was found (31.91%) as compared to bare Fe3O4 NPs under the conditions investigated in this work. Eventually, it was observed that the modified NPs (i.e., FPVA and FPAM NPs) effectively enhanced the properties of the bare Fe3O4 NPs by improving the hydrophilicity of the carbonate rock surface.

Effect of XlogP and hansen solubility parameters on the prediction of small molecule modified docetaxel, doxorubicin and irinotecan conjugates forming stable nanoparticles

Small molecule-chemotherapeutic drug conjugate nanoparticles (SMCDC NPs) has a great advantage in improving drug loading. However, the factors which influence these conjugates forming stable nanoparticles (NPs) are currently unclear. In our previous studies, we synthesized a series of fatty acid-paclitaxel conjugates and suggested that the changes in the hydrophobic parameters (XlogP), solubility parameters and crystallinity of these fatty acid-paclitaxel conjugates were the key factors for affecting these small molecule-chemotherapeutic drug conjugates (SMCDCs) forming stable NPs in water. Here, we selected clinically widely used chemotherapeutic drug (docetaxel (DTX), doxorubicin (DOX) and irinotecan (Ir)) as model drug, and chose three straight-chain fatty acids (acetic acid (Ac), hexanoic acid (HA) and stearic acid (SA)) and one branched small molecule (N-(tert-butoxycarbonyl) glycine (B-G)) to synthesize 12 SMCDCs. Our results indicated that our prediction criterions obtained from paclitaxel conjugates were also appropriated for these synthesized SMCDCs. We suggested that the present studies expanded the scope of application of the above-mentioned influencing factors, provided research ideas for the rational design of SMCDC forming NPs and a basis for screening NPs with good anticancer activity.

The influences of surface polar unit density on the water dispersity of nanoparticles

The impacts of surface polar unit density on the water dispersity of nanoparticles have been investigated using molecular dynamics simulations. The nanoparticles with various polar unit densities were designed by assigning partial charges on different numbers of surface atoms of C60s. The water dispersity of the nanoparticle is enhanced rapidly as the introduction of surface polar atoms. Nevertheless, when the number of polar atoms (N) grows beyond a certain value, the change in the nanoparticle's water dispersity is relatively small. The hydration behaviors of nanoparticles were then studied to investigate the dependence of water dispersity on the surface polar unit density. The introduction of surface polarity enhances the interaction potential between the hydration water and the nanoparticle (Uwater−NP) which should facilitate the dissolution of nanoparticles. On the other hand, the surface polarity also reduces the number of hydrogen bonds formed by a water molecule in the hydration layer with other water molecules (NHB) and enhances the interaction potential between the contacted nanoparticles (UNP−NP) which may hinder their dispersion. However, Uwater−NP, NHB, and UNP−NP all change non-monotonically with N. Moreover, the surface polarity also rearranges the hydration structure of the nanoparticle, which also changes non-monotonically with N. The dependence of the nanoparticle's water dispersity on the surface polar unit density should be attributed to the interplay of different aspects of nanoparticle's hydration behavior, especially the interplay of Uwater−NP, UNP−NP, and NHB.