Digestive Ripening Research Articles

Ultrathin Gd-Oxide Nanosheet as Ultrasensitive Companion Diagnostic Tool for MR Imaging and Therapy of Submillimeter Microhepatocellular Carcinoma.

Early stage hepatocellular carcinoma (HCC) presents a formidable challenge in clinical settings due to its asymptomatic progression and the limitations of current imaging techniques in detecting micro-HCC lesions. Addressing this critical issue, we introduce a novel ultrathin gadolinium-oxide (Gd-oxide) nanosheet-based platform with heightened sensitivity for high-field MRI and as a therapeutic agent for HCC. Synthesized via a digestive ripening process, these Gd-oxide nanosheets exhibit an exceptional acid-responsive profile. The integration of the ultrathin Gd-oxide with an acid-responsive polymer creates an ultrasensitive high-field MRI probe, enabling the visualization of submillimeter-sized tumors with superior sensitivity. Our research underscores the ultrasensitive probe's efficacy in the treatment of orthotopic HCC. Notably, the ultrasensitive probe functions dually as a companion diagnostic tool, facilitating simultaneous imaging and therapy with real-time treatment monitoring capabilities. In conclusion, this study showcases an innovative companion diagnostic tool that holds promise for the early detection and effective treatment of micro-HCC.

Green Capping Agents and Digestive Ripening for Size Control of Magnetite for Magnetic Fluid Hyperthermia

Background: Magnetite is the most recognized iron oxide candidate used for various biological applications. Objective: This work is a complete study that addresses the synthesis of magnetic nanoparticles and investigates the feasibility of using green tea and ascorbic acid as capping agents. Methods: Synthesis of magnetite by two wet chemical methods namely: coprecipitation and solvothermal methods. The samples were characterized using X-ray diffraction (XRD), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM). Results: The results reveal the impact of coating on the size and morphology of the particles. The study also proves that autoclaving the samples prepared by coprecipitation results in smaller particle size and narrower size distribution due to digestive ripening. In addition, a novel and facile methodology for coating magnetite with polyethylene glycol is presented. The potential of the particles to be used for magnetic fluid hyperthermia is assessed by measuring the specific absorption rate (SAR) of the samples. Conclusión: The results show that all the prepared magnetite samples showed a promising capacity to be used as magnetic fluid hyperthermia agents.

Monodisperse Ag, Au Nanoparticles via Solvated Metal Atom Dispersion and Digestive Ripening in Ionic Liquid.

Digestive ripening (DR) is a postsynthetic protocol for the transformation of a colloid consisting of polydisperse metal nanoparticles (NPs) into a colloid composed of nearly monodisperse metal nanoparticles. This process is brought about by the digestive ripening agent, typically an organic ligand with a long alkyl chain at one end and a functional group at the other, at the boiling point of the solvent in which it is carried out, requiring long periods of time. In this work, digestive ripening of polydisperse Ag and Au nanoparticles brought about by ionic liquids (ILs) under very mild conditions (∼273 K, ∼30 min) to obtain nearly monodisperse nanoparticles has been demonstrated. Herein, the ionic liquid plays a dual role, as a digestive ripening and a stabilizing agent for the nanoparticles. Ionic liquid-assisted digestive ripening under such mild temperatures and short period of time has hitherto not been reported.

One-pot and large-scale production of uniform ytterbium-doped perovskite nanocrystals with controllable optical properties

Monodispersed Yb3+:CsPbCl3 nanocrystals with tunable optical properties were synthesized via a scalable one-pot method. The mechanism of size evolution based on digestive ripening was proposed.

Influence of van der Waals Interactions between the Alkyl Chains of Surface Ligands on the Size and Size Distribution of Nanocrystals Prepared by the Digestive Ripening Process.

Thermal heating of polydispersed nanocrystals (NCs) with surface-active organic ligands in a solvent leads to the formation of monodispersed NCs, and this process is known as digestive ripening (DR). Here, by performing DR on Au NCs using different-chain-length amine and thiol ligands, we evidently show that ligands with C12 chain length result in the formation of NCs with narrow size distributions when compared to C8, C16, and C20 chain length ligands. Furthermore, our findings also show that in the case of alkyl thiol, the NC size remains more or less the same, while the size distribution gets altered significantly with the chain length. On the other hand, both size and size distribution are affected significantly when the alkyl amine chain length is varied. Fourier transform infrared (FTIR) studies indicate that the van der Waals (vdW) interactions are weakest when the amine with C12 carbon chain is used as the DR agent, while in the case of thiols, molecules with C8 and C12 chain lengths have nearly the same vdW interactions (with C12 slightly weaker than C8), which are weaker than those of C16 and C20. Molecular dynamics (MD) simulation results corroborate the experimental observations and suggest that due to more defects in the alkyl chain, the C8 and C12 (amine as well as thiol) ligands are disordered and less stable on Au(111) and Au(100) surfaces. This could result in efficient etching and redeposition, making the ligands with C8 and C12 chain lengths the better DR agents.

Formation of lithium carbonate nano-particles using a massively arrayed microfluidic fiber reactor

Microfluidic-based nanoprecipitation is an important tool in modern process intensification to form nanoparticles with well controlled size, size distribution and surface properties. Lithium carbonate nanoparticles were formed continuously with controlled size distribution in the present work using a vertical microfluidic fiber contactor/reactor. The reactor operates as an industrially relevant massively arrayed microfluidic environment which can be scaled for high throughput. Lithium carbonate nanoparticles are an important intermediate for the mining, recycling and production of lithium ion for batteries, pore formers for fuel cell catalysis, and even in pharmaceuticals. Formation of such nanoparticles in a microfluidic environment has the potential for elegant control of polydispersity, and for the fiber contactor/reactor the micro-environment is massively arrayed and high throughput is simultaneously possible. Continuous microfluidic fractional precipitation of lithium carbonate nanoparticles with diameters as small as 5.9 nm is described. The solvent was a CO2-saturated water solution and the anti-solvent was isopropanol. The effects of process parameters (including temperature, surfactant concentration, antisolvent strength, and process flowrate) on product size and polydispersity were examined. In particular, lower temperatures seemed to produce low polydispersity. The product was characterized using dynamic light scattering (DLS). A computational fluid dynamics model is also presented to predict the nucleation point (along the length of the reactor) where nanoparticles were likely forming. Correlation to crystal growth mechanisms in the reactor and the importance of reactor length (Otswald versus digestive ripening) is discussed, residence time being one potential contributing factor to the low polydispersity.

Ligands as “Matchmakers”: Alloying from a Physical Mixture of Metal Nanoparticle Dispersions by Digestive Ripening

Digestive ripening (DR) of a physical mixture of different metal nanoparticles (NPs) in the presence of a suitable ligand is demonstrated to be a convenient way to obtain alloy NPs. The results show that the right choice of metal-ligand combination is extremely important for efficient alloying. The results are rationalized on the basis of hard soft acid base principles, and it is concluded that better alloying ensues if DR is carried out with soft ligands when soft metals are being used and hard ligands facilitate alloying between hard metals. On the other hand, when a physical mixture of hard-soft metals is taken, ligands with intermediate character work better. The results presented here could prove to be extremely valuable and open new avenues of making interesting alloy/intermetallic systems.

Polymer-Stabilized Au38 Cluster: Atomically Precise Synthesis by Digestive Ripening and Characterization of the Atomic Structure and Oxidation Catalysis

Polymer-Stabilized Au₃₈ Cluster: Atomically Precise Synthesis by Digestive Ripening and Characterization of the Atomic Structure and Oxidation Catalysis

Identification of an amorphous-amorphous two-step transformation in indomethacin embedded within mesoporous silica

A very unusual amorphous-amorphous two-step transformation was observed in indomethacin confined within MCM-41 mesoporous silica, via isothermal and non-isothermal routes. Isothermally, at room temperature, the first step corresponds to the 1-dimensional growth of γ-nanocrystals along the mesoporous channels from preexisting incipient nuclei. In the second step nanocrystals slowly transform into an undercooled liquid state structurally different from the original liquid and characterized by a higher molecular mobility. The instability of nanocrystals detected in the continuation of the isothermal growth was explained as resulting from a very high specific area of nanocrystals imposed by the geometrical confinement when the size of nanocrystals along the channels achieves a dimension much larger than the channel diameter. The mechanism of the slow dissolution of nanocrystals was identified as similar to a digestive ripening process, inverse to the Ostwald ripening, by which larger clusters dissolve to the detriment of smaller ones. This two-step transformation was also observed upon heating. In this case, the growth of nanocrystals is followed by a melting far below the melting point of γ-crystals, according to Gibbs-Thomson effects. This study shows that the original amorphous form of indomethacin transforms into a second amorphous form via the transient growth of nanocrystals which become unstable via two different mechanisms induced by the geometrical confinement. • MAL method allows crystallization within MCM-41 bypassing the nucleation process. • MCM-41 geometry induces nanocrystal instability in the course of their growth. • Two-step amorphous-amorphous transformation via nanocrystallization under confinement.

Digestive ripening yields atomically precise Au nanomolecules

Atomically precise Au nanomolecules yielded through digestive ripening establishes that regardless of the pathway, both DR and Brust methods lead to the formation of atomic precise Au NMs.

CH3NH3PbBr3-xIx Quantum Dots Enhance Bulk Crystallization and Interface Charge Transfer for Efficient and Stable Perovskite Solar Cells.

Obtaining a perovskite light-absorbing layer with good crystallization, low defect concentration, good stability, and well-matched energy levels is critical to obtaining high-efficiency perovskite solar cells (PSCs). Here, a hybrid PSC with a graded band gap is explored using MAPbBr3 (MA = CH3NH3) and MAPbBr0.9I2.1 quantum dots (QDs) as component cells. We have creatively designed a solar cell device with a double-QD structure [indium tin oxide (ITO)/SnO2/perovskite:MAPbBr3 QDs/MAPbBr0.9I2.1 QDs/Spiro-OMeTAD/Au]. A better crystal film of the perovskite absorption layer can be obtained because the MAPbBr3 QDs are doped in an antisolvent, which induces nucleation and growth in the polycrystalline perovskite. In addition, we expect that digestive ripening occurred in the crystallization, and the oleic acid ligands on the surface of the QDs disintegrate during the doping process and transfer to the surface of the perovskite absorption layer finally; it follows that the hydrophobicity and stability of the perovskite film are greatly enhanced. Moreover, a thin film of MAPbBr0.9I2.1 QDs is introduced between the perovskite absorption layer and the hole layer, acting as an energy-level ladder, which leads to well-matched energy levels, an increase in fill factor (FF), and an enhanced hole transport capability. In particular, the mechanism of the crystallization process involving the effect of oleic acid ligands on the interior and surface of the perovskite film is fully discussed here. The final research results from the PSCs show that both high efficiency and long-term stability are achieved successfully by this design strategy.

On the Digestive Ripening Mechanism

The theories of Lee et al. and Lifshitz–Slezov–Wagner were considered for digestive ripening, which is a relatively new method of regulating the size distribution function of nanoparticles consisting in dissolution of large nanoparticles and formation of small ones in contrast to Ostwald ripening. It was shown that these theories did not give a reasonable explanation of this phenomenon. The process mechanism was substantiated based on taking into account the dependence of the critical radius of the nanoparticle on the concentration of monomer units and the size of the ligand layer.

Influence of ligand's thermal stability on size and self-assembly of Cu nanoparticles

In this work, we report the effect of thermal stability of various capping ligands in modified digestive ripening (MDR) technique for probing the mechanism of formation of self-assembled monodipserse Cu nanoparticles from the polydisperse Cu nanoparticles. Narrowing of the size distribution of monodisperse Cu nanoparticles after modified digestive ripening process is strongly dependent on the thermal stability of capping ligands. Various capping ligands such as dodecanethiol (DDT), octadecanethiol (ODT) and mixture of DDT and ODT are successfully used in modified digestive ripening method and performed the process at various temperatures (60, 120 and 180 °C) to study the effect of thermal stability of these ligands on the size and self-assembly of cu nanoparticles. Using DDT as capping ligand, decrease in particles size and monodispersity observed at 60 °C and complete monodispersity is achieved after 120 °C due to low thermal stability of DDT. However, with ODT and multi ligands, complete monodispersity is achieved at 180 °C due to high thermal stability of ODT as compared to DDT.

Monodisperse Gold Cuboctahedral Nanocrystals Directly Synthesized in Reverse Micelles: Preparation, Colloidal Dispersion in Organic Solvents and Water, Reversible Self-Assembly and Plasmonic Properties.

The synthesis of organic-solvent-dispersible gold nanoparticles in reverse micelles of didodecyldimethylammonium bromide (DDAB) is revisited in the present investigation. Some parameters of synthesis, specifically the reaction volume and the concentration of the reducing agent, were slightly modified obtaining directly monodisperse gold nanocrystals (AuNCs) without the need to use additional active surfactants or additional treatments such as digestive ripening. Interestingly, most of the obtained AuNCs display the same exposed crystalline faces composed of six bounding facets (four {111} faces and two {002} faces), corresponding to single-crystalline face-centered cubic nanoparticles with a cuboctahedron shape. When these AuNCs are subsequently functionalized with 1-decanethiol (C10H21SH) or 1-dodecanethiol (C12H25SH), they don't experience significant changes in their size or crystalline texture, however, they self-aggregate directly in the suspension at room temperature into faceted supramolecular structures and exhibit collective plasmonic excitations. Such self-organization is reversible under heating treatments allowing the observation of the influence of the AuNCs aggregation state on their plasmonic properties. Fourier transform infrared spectroscopy reveals that thiols only replace partially the DDAB molecules, and thus, DDAB molecules remain present in the thiol-capped AuNCs. To turn the thiol-capped nanocrystals into water-dispersible nanocrystals and extend their technological potential, they are stabilized with poloxamer 407 obtaining highly stable purple colloids in water.

Two Growth Mechanisms of Thiol-Capped Gold Nanoparticles Controlled by Ligand Chemistry.

Thiols play an important role in the synthesis of well-defined nanoparticles (NPs) with tailored properties, but their effects on the formation kinetics of NPs are still under investigation. Here, we used in situ small-angle X-ray scattering (SAXS)/UV-vis spectroscopy and time-dependent transmission electron microscopy (TEM) to elucidate the role of thiols in the formation process of gold NPs (AuNPs) by changing the adding sequence between thiol ligand and reducing agent. Through quantitative analysis of in situ SAXS/UV-vis and TEM, detailed information on size, size distribution, the number of particles, optical properties, and the size evolution was obtained. Two different growth mechanisms of monodisperse AuNPs controlled by thiol ligand are exhibited: (i) thiol plays a dual role as a digestive ripening etchant and as a stabilizing ligand in the presence of a weak phosphine ligand. The digestive ripening mechanism involving the dissolution of bigger particles and subsequent deposition of monomers onto existing small NPs is responsible for producing narrowly dispersed NPs. (ii) Thiol acts as a strong stabilizing agent; in this case, the formation rate constant is quite slow, thus limiting the growth rate of NPs. Therefore, diffusion-limited growth mechanism is proposed for obtaining narrowly dispersed NPs with a diameter of 5.6 nm (12%). Our findings demonstrate that the formation of nearly monodisperse AuNPs with controllable size distribution could be realized by different growth mechanisms in the presence of thiol ligand.

Nanocomposites of digestively ripened copper oxide quantum dots and graphene oxide as a binder free battery-like supercapacitor electrode material

Ultra-small (r < 2 nm), semiconductor quantum dots (QDs) based composites are underexplored in electrochemical energy-storage devices. This is due to practical challenges associated with synthesis of QDs such as (i) stabilization, (ii) scalability, and (iii) achieving monodispersed population. In this context, ultra-small, highly monodispersed copper oxide QDs (∼2.5 ± 0.4 nm) have been synthesized by using soft-chemical and scalable approach based on digestive ripening. Composites of digestively ripened (DRd) copper oxide QDs deposited on graphene oxide are tested electrochemically for battery-like supercapacitor. The composites are grown in-situ on a Ni-foam to make binder-free battery-like supercapacitor electrode by hydrothermal process. Results indicates that battery-like behavior of the composites. Among the composites, 50%QDs-GO provides maximum specific capacity of 191 mA h g−1 at 2 mV s−1 which is maintained up to 63 mA h g−1 even at a high scan rate of 200 mV s−1. The specific capacity increases ∼4 times for the 50%QDs-GO composite, compared to the graphene oxide. The maximum energy density provided by the system is 57.2 Wh kg−1 at 2 mV s−1. Specific capacity and charge-discharge stability of the composites are found to be improved with increasing concentration of QDs. This is the first report on deployment of DRd copper oxide QDs in battery-like supercapacitors and it opens up possibilities for further exploration of other DRd QDs.

Evolution of Silver Nanoparticles Synthesized In Situ in a Glass-Like Epoxy Matrix

The evolution of silver nanoparticles (NPs) synthesized in situ in an epoxy matrix is investigated. The change in the stability of epoxy nanocomposites as a result of secondary processes of the transformation of NPs in a glass-like epoxy matrix when stored under natural light and in darkness is shown by means of absorption spectroscopy. The first order of the reaction and the dependence of the rate constant on the concentration of the precursor are found. Possible mechanisms for the conversion of silver NPs (e.g., digestive ripening and the formation of anisotropic structures) are discussed. It is concluded that the glass-like state of the polymer matrix is not a sufficient condition for the stabilization of NPs or the stability of the properties of the nanocomposite. This must be considered in the study and practical application of polymer nanocomposites (NCs) based on metal nanoparticles.

On the mechanism of the process of digestive ripening

The literature describes a relatively new method of regulating the size distribution function of nanoparticles - the process of digestive ripening, which, unlike Ostwald ripening, consists in dissolving large nanoparticles and forming small ones. However, a reasonable explanation of this phenomenon is still missing. The work substantiates the mechanism of the process, based on taking into account the dependence of the critical radius of the nanoparticle on the concentration of monomeric units and the size of the ligand layer.

On the Digestive Ripening Mechanism

The literature describes a relatively new method of regulating the size distribution function of nanoparticles, namely, the process of digestive ripening, which, unlike the Ostwald ripening, implies the dissolution of large nanoparticles and the formation of small ones. However, there is still no reasonable explanation of this phenomenon. The work substantiates the mechanism of the process, based on taking into account the dependence of the critical radius of the nanoparticle on the concentration of monomeric units and the size of the ligand layer.

Physicochemical properties of chimie douce derived, digestively ripened, ultra-small (r

Ultra-small and uniform sized ZnO quantum dots (QDs) have been synthesized by using a chimie-douce, scalable and eco-friendly method. The physicochemical properties of digestively ripened ZnO QDs have been explored. Uniform sized colloidal QDs are achieved by employing a size control approach called digestive ripening (DR). In DR, monodispersed colloidal nanoparticles are obtained from polydispersed colloidal nanoparticles through the addition of substantial amount of a suitably chosen surfactant (having a suitable ligand). This is performed in the presence of a suitable solvent. Capping with the surfactant (triethanolamine) results in a change in the zeta potential of QDs (increased from 7 ± 3 mV to +22 ± 3 mV) which is responsible for the observed DR and a decrease in particle size from ˜3.5 ± 2 nm to ˜2.8 ± 0.5 nm also noticed. Hard-Soft-Acid-Base surface chemical interactions taking place between ZnO QDs and the surfactant (triethanolamine) are responsible for the formation of digestively ripened ZnO QDs. The as formed ZnO QDs are highly monodispersed in nature and the optical absorption studies indicate that band gap of ZnO QDs found to be Eg˜3.6 eV, indicating strong confinement. The photoluminescence (PL) studies clearly indicates that the major contribution to the photoluminescence is defects present of ZnO QDs-surface and the existence of oxygen vacancy defects on the ZnO QDs-surface are confirmed with PL studies. Time-resolved photoluminescence studies indicate that lifetimes of photo-generated carriers in digestively ripened (DRd) QDs is ˜12 ns and coating with digestive ripening agent reduces the surface-related emission and improves the radiative transitions in DRd ZnO QDs. Spectroscopic studies indicate that formation of highly pure ZnO QDs. These highly monodisperse, stable and ZnO QDs are prospectively useful in contemporary applications such as nanoscale electronic devices and photocatalysis.