Stability In Aqueous Phase Research Articles

(Invited) Selective Glucose Conversion into Gluconic Acid By Dye-Sensitized Photoelectrochemical Cell

Gluconic acid, one of the valuable products of oxidized glucose projected to soon hit a market value of US$1.9 billion is currently produced using relatively expensive electrochemical, environmentally unsafe chemical or thermal selective oxidation methods to meet market demand. Dye-sensitized photoelectrochemical cells (DSPECs) which has effectively been utilized for selective biomass conversion into other valuable products (alongside hydrogen evolution) is a cheaper, greener and safer alternative unexplored in this field. Herein, we explore this green technology for selective oxidation of glucose into gluconic acid in an aqueous system, employing metal-free organic dye (E)-3-(5-(4-(bis(2',4'-dibutoxy-[1,1'-biphenyl]-4-yl) amino) phenyl) thiophen-2-yl)-2-cyanoacrylic acid (D35) with organic catalyst (4-Acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl) ACT at 0 V vs NHE. Photophysical details revealed the occurrence of intermolecular electron transfer between D35 and ACT under 1 sun illumination (100 mW/cm²). Enhanced generation of the strongly oxidizing reactive oxoammonium species, ACT+, by the photoanode drives the conversion of glucose into gluconic acid. The photoanode assembly employed exhibited remarkable stability, sustaining a continuous operation for 3 days and 88% selectivity for gluconic acid at pH 7. The aqueous phase stability, selectivity, neutral environment and ambient operation of the setup indicates it potential for biomass conversion and hydrogen production towards commercialization purposes.

Exceptional Stability against Water, UV Light, and Heat for CsPbBr3@Pb-MOF Composites.

All-inorganic lead halide perovskite nanocrystals (NCs) have been widely applied in optoelectronic devices owing to their excellent photoluminescence (PL) properties. However, poor stability upon exposure to water, UV light or heat strongly limits their practical application. Herein, CsPbBr3@Pb-MOF composites with exceptional stability against water, UV light, and heat are synthesized by ultrasonic processing the precursors of lead-based MOF (Pb-MOF), oleylammonium bromide (OAmBr) and cesium oleate (Cs-OA) solutions at room temperature. Pb-MOF can not only provide the lead source for the in situ growth of CsPbBr3 NCs, but also the protective layer of perovskites NCs. The formed CsPbBr3@Pb-MOF composites show a considerable PL quantum yield (PLQY) of 67.8%, and can maintain 90% of the initial PL intensity when immersed in water for 2 months. In addition, the outstanding PL stability against UV light and heat is demonstrated with CsPbBr3 NCs synthesized by the conventional method as a comparison. Finally, a green (light-emitting diode) LED is fabricated using green-emitting CsPbBr3@Pb-MOF composites and exhibits excellent stability without packaging when immersed in water for 30 days. This study provides a practical approach to improve the stability in aqueous phase, which may pave the way for future applications for various optoelectronic devices.

The novel π–d conjugated TM2B3N3S6 (TM = Mo, Ti and W) monolayers as highly active single-atom catalysts for electrocatalytic synthesis of ammonia

Recently, single-atom catalysts (SACs) are receiving significant attention in electrocatalysis fields due to their excellent specific activities and extremely high atomic utilization ratio. Effective loading of metal atoms and high stability of SACs increase the number of exposed active sites, thus significantly improving their catalytic efficiency. Herein, we proposed a series (29 in total) of two-dimensional (2D) conjugated structures of TM2B3N3S6 (TM means those 3d to 5d transition metals) and studied the performance as single-atom catalysts for nitrogen reduction reaction (NRR) using density functional theory (DFT). Results show that TM2B3N3S6 (TM = Mo, Ti and W) monolayers have superior performance for ammonia synthesis with low limiting potentials of −0.38, −0.53 and −0.68 V, respectively. Among them, the Mo2B3N3S6 monolayer shows the best catalytic performance of NRR. Meanwhile, the π conjugated B3N3S6 rings undergo coordinated electron transfer with the d orbitals of TM to exhibit good chargeability, and these TM2B3N3S6 monolayers activate isolated N2 according to the “acceptance–donation” mechanism. We have also verified the good stability (i.e., Ef < 0, and Udiss > 0) and high selectivity (Ud = –0.03, 0.01 and 0.10 V, respectively) of the above four types of monolayers for NRR over hydrogen evolution reaction (HER). The NRR activities have been clarified by multiple-level descriptors (ΔG*N2H, ICOHP, and Ɛd) in the terms of basic characteristics, electronic property, and energy. Moreover, the aqueous solution can promote the NRR process, leading to the reduction of ΔGPDS from 0.38 eV to 0.27 eV for the Mo2B3N3S6 monolayer. However, the TM2B3N3S6 (TM = Mo, Ti and W) also showed excellent stability in aqueous phase. This study proves that the π-d conjugated monolayers of TM2B3N3S6 (TM = Mo, Ti and W) as electrocatalysts show great potentials for the nitrogen reduction.

Evaluation of hydroxyapatite-chitosan-magnetite nanocomposites for separation of pharmaceuticals from water: A mechanistic and comparative approach

Binary and ternary composites of hydroxyapatite (HAP), chitosan (CT) and magnetite (MNP) were fabricated to assess the individual role of each constituent and to estimate their optimized proportion for maximizing the adsorption of pharmaceuticals (PCs) from aqueous phase. Batch studies carried out with model ibuprofen (IBU) reveal the significant role of HAP in enhancing the adsorption to binary composites (HAP@CT, HAP@MNP, CT@MNP). Among the HAP@CT composites fabricated with varying proportion, CT proportion of ≧ 50% showed improved adsorptive performance. Highest adsorption of IBU was achieved by the ternary composite of NC6 having a HAP: CT: MNP of 2:5:3. FTIR, VSM, Fe-SEM, TEM studies revealed NC6 to possess magnetic properties, better aqueous phase stability, higher surface area, higher crystallite sized nanoparticles with less agglomeration, and adequate surface functionality as compared to its precursors. The high efficiency and fast kinetics for Ibuprofen (IBU), Deflazacort (DEF), Methylprednisolone (MET) and Norfloxacin (NOR) could be corelated with the structural and physico-chemical nature of the PCs in aqueous phase. Langmuir adsorption capacity of 535.6 mg/g, 833 mg/g, 625 mg/g and 714 mg/g for NOR IBU, MET and DEF respectively was reported with NC6 dosage of 0.01 g/L. NC6 demonstrated faster equilibration time of 30–90 mins with > 85% PCs removal as compared to other reported composites. The results of this study reveal the efficacy of NC6 for fast and high adsorptive removal of diverse types of PCs from both model and hospital wastewater. Also, the reusability and biogenic nature of NC6 is established.

A flexible and scalable scheme for mixing computed formation energies from different levels of theory

Computational materials discovery efforts are enabled by large databases of properties derived from high-throughput density functional theory (DFT), which now contain millions of calculations at the generalized gradient approximation (GGA) level of theory. It is now feasible to carry out high-throughput calculations using more accurate methods, such as meta-GGA DFT; however recomputing an entire database with a higher-fidelity method would not effectively leverage the enormous investment of computational resources embodied in existing (GGA) calculations. Instead, we propose here a general procedure by which higher-fidelity, low-coverage calculations (e.g., meta-GGA calculations for selected chemical systems) can be combined with lower-fidelity, high-coverage calculations (e.g., an existing database of GGA calculations) in a robust and scalable manner. We then use legacy PBE(+U) GGA calculations and new r2SCAN meta-GGA calculations from the Materials Project database to demonstrate that our scheme improves solid and aqueous phase stability predictions, and discuss practical considerations for its implementation.

Evaluation of DNA/BSA interaction and in vitro cell cytotoxicity of μ2-oxido bridged divanadium(V) complexes containing ONO donor ligands

Two new μ2-oxido bridged divanadium (V) complexes, [VV2O3(L1,2)2] (1 and 2) have been synthesized using bi-negative tridentate ONO-donor ligands, H2L1,2 (H2L1 = 4-tert-butyl-2-[[[3,5-di-tert-butyl-2-hydroxyphenyl]methylene]amino]phenol and H2L2 = 5-bromo-2-[[[4-(diethylamino)-2-hydroxyphenyl]methylene]amino]phenol). The synthesized ligands and complexes have been characterized through FT-IR, UV‐vis, NMR, and HR-ESI-MS techniques. Single crystal X-ray crystallography data confirmed distorted square pyramidal geometry for both the complexes. The aqueous phase stability of these complexes has been evaluated through HR-ESI-MS in CH3CN:H2O (80:20) mixture. Thereafter their interaction with calf thymus DNA (CT-DNA) have been studied using electronic absorption and fluorescence spectroscopy, revealing an intercalation mode of binding, with binding constant in the order of 104 M−1. Moreover, bovine serum albumin (BSA) interaction of 1 and 2 has been evaluated via fluorescence quenching experiment, which suggests that the quenching mechanism is static (~1013 M−1) in nature. Additionally, the in vitro cytotoxicity of the complexes has been evaluated in human cervical cancer cells (HeLa) (IC50 = 13.57–16.62 μM) and normal mouse embryonic fibroblasts cells (NIH-3T3). The mechanism of cell death brought about by these complexes was studied by nuclear staining, cell cycle and Annexin V/PI double staining apoptotic assay. These studies indicate that 1 and 2 exert inhibitory effects on the S and G2M phase of cell cycle, which is an indication of apoptotic cell death. Also, a clonogenic assay was performed, which showed that the complexes could effectively inhibit colony formation.

The kinetic behavior of antioxidant activity and the stability of aqueous and organic polyphenol extracts from navel orange peel

The kinetic behavior of the antioxidant activity of aqueous/organic polyphenol extracts from navel orange peel was evaluated using DPPH and FRAP assays to assess their capacity to scavenge DPPH and ferric reducing antioxidant power. The stability of polyphenol extracts, including the influencing factors of temperature, pH, light, and the correlation of total phenolic content and antioxidant activity were also investigated. The kinetic reaction results showed that the antioxidant activity i.e. DPPH radical scavenging capacity and ferric reducing antioxidant power depended on concentration and reaction time. Its stability in aqueous phase and organic phase was influenced by temperature, pH and light in varying degrees. 50 °C was a key temperature point above which the total polyphenol content and antioxidant ability decreased remarkably. The phenolic compounds were not stable at pH 7, but showed a strongest DPPH radical scavenging capacity in both aqueous and organic phases. Acidic conditions seemed to be better for maintaining antioxidant ability of extracts from navel orange peel than alkaline conditions in aqueous and organic phases. Avoiding light kept the extracted phenolic compounds stable. There is a significant correlation between total phenolic content and antioxidant activity. These results provide some basic understanding of extracts from navel orange peel and promote the application of the extracted polyphenol from navel orange peel as antioxidants.

Theoretical conformations studies on 2-Acetyl-gamma-butyrolactone structure and stability in aqueous phase and the solvation effects on electronic properties by quantum computational methods

The 2-Acetyl-gamma-butyrolactone (2-AgBL) was characterized by quantum computational studies with DFT approaches. A relaxed PES scan was employed in this study to determine the order of stability conformations in the vacuum and aqueous phases, and then dimerization for the stable conformer was done in water phase. The molecular structure and geometries of monomer, as well as a dimer for the stable conformer were obtained, and they were confirmed by theoretical IR spectroscopy. The ELF, LOL, QTAIM and NCI-RDG techniques are utilized to explore weak donor strong acceptor (CH···OC) type hydrogen bonds and other non-covalent interactions in dimer. The stability of compound was internally assessed by the NBO analysis in different mediums. On the gas and solvent phases: UV–Vis absorptions, Molecular Electrostatic potentials, global reactive parameters (FMOs), and Fukui Functions analysis were also performed in this study. A Solute-solvent interaction center was found in the water solvent for 2-AgBL.

Creation of a robust and R-selective ω-amine transaminase for the asymmetric synthesis of sitagliptin intermediate on a kilogram scale

The creation of an R-selective ω-amine transaminase (ω-ATA) as biocatalyst is crucial for the asymmetric amination of prochiral ketones to produce sitagliptin intermediates because rare ω-ATAs are R-selective in nature and most of them suffer from poor stability and low activity toward bulky prochiral ketones. Here, the gene of an R-selective ω-ATA was cloned from Arthrobacter cumminsii ZJUT212 (AcATA) and expressed in Escherichia coli. The best variants (M1 + M122H and M1+T134 G) were obtained using a semi-rational protein design after screening. These variants not only exhibited improved activity and substrate affinity but also enhanced stability in aqueous phase containing 20 % dimethyl sulfoxide. The conversion of asymmetric amination on 50 g/L pro-sitagliptin ketone PTfpB (1-[1-piperidinyl]-4-[2,4,5-trifluorophenyl]-1,3-butanedione) achieved 92 %, with an extremely high e.e. of >99 %, using 2 gDCW/L E. coli cells harboring M1 + M122H as biocatalyst. In the kilogram-scale experiment, approximately 40 kg of (R)-APTfpB (e.e. >99 %) was produced within 30 h when 50 kg PTfpB was used as the substrate. Furthermore, the space–time yield reached ≈32 g/(L·d).

One-pot aqueous-phase xylose upgrading on Zr-containing BEA zeolites

Xylose transformation into furfuryl alcohol was performed over modified BEA zeolites. BEA acidity was modified by incorporating Zr into zeolite by a post-synthesis procedure. HAlBEA showed to be selective towards furfuryl alcohol under reaction conditions used. Zr-containing zeolites were more active than the corresponding BEA catalysts but their efficiency to promote xylose conversion to furfuryl alcohol was related to Zr atoms incorporated in the framework. High Zr loadings generated isolated ZrO2 which promoted xylose isomerization to xylulose. It was associated with the depletion of Brønsted acid sites since presence of Brønsted and Lewis acid centres are crucial for the cascade process to furfuryl alcohol. ZrHAlBEA catalyst exhibited no significant deactivation upon four reaction cycles. Products distribution was not affected either, indicating that Brønsted and Lewis acid sites are preserved under the reaction conditions. Neither Al nor Zr were leached from the catalysts structure, corroborating their chemical stability in aqueous phase.

A Water-Stable Ionic MOF for the Selective Capture of Toxic Oxoanions of SeVI and AsV and Crystallographic Insight into the Ion-Exchange Mechanism.

Selectively capturing toxic oxoanions of selenium and arsenic is highly desired for the remediation of hazardous waste. Ionic metal-organic frameworks (iMOFs) especially cationic MOFs (iMOF-C) as ion-exchange materials, featuring aqueous phase stability, present a robust pathway for sequestration of the oxoanions owing to their ability to prevent leaching because of their ionic nature. On account of scarcity of water-stable cationic MOFs, the capture of oxoanions of selenium and arsenic has been a major challenge and has not been investigated using iMOFs. Herein, we demonstrate large scale synthesis of cationic MOF, viz. iMOF-1C that exhibits selective capture of oxoanions of SeVI (SeO42- ) and AsV (HAsO42- ) in water with a maximum sorption capacity of 100 and 85 mg g-1 , respectively. This represents among the highest uptake capacities observed for selenate oxoanion in MOFs. Further, the ion-exchange mechanism was directly unveiled by single crystal analysis, which revealed variable modes of host-guest binding.

A Water‐Stable Ionic MOF for the Selective Capture of Toxic Oxoanions of SeVI and AsV and Crystallographic Insight into the Ion‐Exchange Mechanism

AbstractSelectively capturing toxic oxoanions of selenium and arsenic is highly desired for the remediation of hazardous waste. Ionic metal–organic frameworks (iMOFs) especially cationic MOFs (iMOF‐C) as ion‐exchange materials, featuring aqueous phase stability, present a robust pathway for sequestration of the oxoanions owing to their ability to prevent leaching because of their ionic nature. On account of scarcity of water‐stable cationic MOFs, the capture of oxoanions of selenium and arsenic has been a major challenge and has not been investigated using iMOFs. Herein, we demonstrate large scale synthesis of cationic MOF, viz. iMOF‐1C that exhibits selective capture of oxoanions of SeVI (SeO42−) and AsV (HAsO42−) in water with a maximum sorption capacity of 100 and 85 mg g−1, respectively. This represents among the highest uptake capacities observed for selenate oxoanion in MOFs. Further, the ion‐exchange mechanism was directly unveiled by single crystal analysis, which revealed variable modes of host–guest binding.

Effect of ultra-sonication and peptization on the aqueous phase stability of iron oxide nanoparticles

Since ensuring stability of the nanoparticles in aqueous-phase is essential for biomedical applications, this study evaluated the effect of ultra-sonication followed by peptization on iron-oxide nanoparticles (IONPs) aqueous-phase stability. The IONPs synthesized via two different chemical co-precipitation methods were ultra-sonicated for −5, −10 and 20-min and evaluated using Dynamic light scattering at Day-1, -2, -7 and -15 of the synthesis. The Experiment II-IONPs had lesser hydrodynamic size with better aqueous-phase stability over the time. The decrease in the average size and increase in homogeneity of solution was better following ultra-sonication for 20-min. These IONPs were peptized with perchloric acid to evaluate the effect on stability and longevity. The results showed large proportion of IONPs less than 100 nm even on day-15 post-peptization. Moreover, transmission electron microscopy revealed average size of 11.23 nm with round shape. The study showed positive influence of peptization on the aqueous-phase stability of the IONPs.

Switchable control of hydrophilicity and hydrophobicity in conjugated polymer nanoparticles by carbon dioxide

We synthesized yellow-emissive, fluorine-based conjugated polymer to fabricate CO2-responsive conjugated polymer nanoparticles (CPNPs). The CPNPs were functionalized with tertiary amine to have responsiveness to CO2. The amine-functionalized CPNPs became hydrophilic by CO2, bubbling because the bubbling led to formation of cationic ammonium ions at the side chains of the hydrophobic CPNPs. This resulted in high dispersion stability in aqueous phase even after vigorous mixing in the presence of organic phase (1-octanol). Subsequent N2 bubbling was done to remove CO2 present in water, leading to deprotonation of the side chains of CPNPs. The CPNPs became hydrophobic and moved to the organic phase. The CO2-responsive property was based on the amine groups in the side chain of polymer that reversibly interacted with bicarbonate ion (HCO3-), formed by dissolving CO2 in water, generating switchable hydrophilicity and hydrophobicity.

Methane hydrate formation improved by water-soluble carbon nanotubes via π-π conjugated molecules functionalization

The carbon nanotubes (CNTs) have been reported as an efficient kinetic promoter for hydrate formation. However, their effects would be weakened by the severe aggregation of the hydrophobic nanotubes. In this work, the carbon nanotubes coated by π-π conjugated molecules of reactive red 195 (RR195) was prepared using method of either sonication or ball milling. These functionalized CNTs showed highly solubility and stability in aqueous phase. When the water-soluble coated CNTs (RR195@CNTs) was used in hydrate reaction system, the formation could finish within the shortest time of 203 ± 20 min and the gas storage capacity was improved from 40 ± 8 v/v in deionized water to the high value of 140 ± 2 v/v in the RR195@CNTs dispersion. In comparison, the ball milling treated CNTs showed preferable promotion effect on both expediting hydrate formation and elevating the energy storage efficiency. Moreover, the sonication treated CNTs had only three times of favorable recycling uses, while seven cycles of hydrate formation-dissociation processes were achieved with the ball milling treated CNTs as promoter. Besides, the formed methane hydrates with RR195@CNTs as promoters generated no foams during the dissociation process, which was also welcomed in the actual hydrate-based natural gas release and utilization process.

Magnetically separable indium doped ZnS[sbnd]NiFe2O4 heterostructure photocatalyst for mineralization of acid violet 7 dye

A new magnetically separable visible light active indium doped ZnSNiFe2O4 photocatalyst is synthesized and evaluated for the photodegradation of acid violet 7 (AV-7) dye. Characterization of nanocomposite suggests that indium doped ZnS exists in hexagonal structure, while NiFe2O4 is in the cubic structure and they are found to be in a highly dispersed state. The optical property of ZnSNiFe2O4 composite is improved after indium doping and considerable visible light absorption is observed. Magnetic study suggests that the composite is a soft magnetic material having ferrimagnetic property, which allows easy separation of catalyst from the aqueous suspension using an external magnetic field. The photodegradation study of AV-7 using indium doped composite shows better degradation kinetics than the corresponding indium doped ZnS, NiFe2O4 and ZnSNiFe2O4. Further, total organic carbon (TOC) analysis revealed that total mineralization of AV-7 occurs within 60 min of visible light irradiation. Electrochemical results suggest better charge-storage capacitance behaviour, improved charge carrier transport and enhanced aqueous phase stability for the composite compared to NiFe2O4 and ZnS. In addition, photocurrent and life time measurements suggest considerable separation of electron-hole pair in indium doped ZnSNiFe2O4 nanocomposite over indium doped ZnS. Current results provide new insights in developing and designing recyclable photocatalyst. The magnetic properties of this composite eliminate the risk of secondary pollution and easy recovery of the catalyst.

Influence of a thin aluminum hydroxide coating layer on the suspension stability and reductive reactivity of nanoscale zero-valent iron

A novel structured material, aluminum hydroxide–coated nanoscale zero-valent iron (NZVI@Al(OH)3), was synthesized to improve the applicability of NZVI in environmental remediation. Using a rate-control precipitation method, the surface of NZVI was covered with a thin shell of amorphous Al(OH)3. ζ-potential of NZVI under a weak alkaline condition became positive after coating with the Al(OH)3 shell. NZVI@Al(OH)3 performed remarkably higher suspension stability in aqueous phase than bare NZVI, owing to the increased electrostatic repulsion and the reduction of magnetic attraction between the NZVI@Al(OH)3 particles. Results of H2 generation test indicated that the pH buffering capacity of the Al(OH)3 shell and the enlarged surface area benefitted the reductive reactivity of NZVI@Al(OH)3. Additionally, the adsorption capability of the positive Al(OH)3 shell facilitated the reduction and detoxification of contaminants on the NZVI surface. Consequently, the core-shell structure dependent modification with a thin inorganic shell with multiple functions is a promising design for environmental nanomaterials, and the NZVI@Al(OH)3 synthesized in this study is a feasible and environmentally benign material for environmental remediation.

Surface modification of silica-graphene nanohybrid as a novel stabilizer for oil-water emulsion

The surface modification of silica-graphene nanohybrid through treatment with a mixture of nitric and sulfuric acid vapors to prepare a novel stabilizer for decalin-water emulsion was investigated. The nanohybrid was prepared through chemical vapor deposition using silica aerogel and acetylene as catalyst and carbon precursor at atmospheric pressure and 600 °C. The physicochemical properties of the modified nanohybrid were characterized by FT-IR, XPS, Raman spectroscopy, and TEM. The surface modification of nanohybrid was at various duration times (24, 48, and 72 hours) to optimize the surface modification conditions. Zeta potential of −39.9 mV revealed that the surface modification of nanohybrid after 72 hours had an excellent stability in aqueous phase due to the presence of exceptional functional groups. The emulsion average droplet size decreased by increasing the nanohybrid concentration. The negative value of the zeta potential showed the proposed nanohybrid can be applied as an appropriate stabilizer for emulsion.

One-step microwave-assisted synthesis of water-dispersible Fe3O4 magnetic nanoclusters for hyperthermia applications

To realize magnetic hyperthermia as an alternate stand-alone therapeutic procedure for cancer treatment, magnetic nanoparticles with optimal performance, within the biologically safe limits, are to be produced using simple, reproducible and scalable techniques. Herein, we present a simple, one-step approach for synthesis of water-dispersible magnetic nanoclusters (MNCs) of superparamagnetic iron oxide by reducing of Fe2(SO4)3 in sodium acetate (alkali), poly ethylene glycol (capping ligand), and ethylene glycol (solvent and reductant) in a microwave reactor. The average size and saturation magnetization of the MNC’s are tuned from 27 to 52nm and 32 to 58emu/g by increasing the reaction time from 10 to 600s. Transmission electron microscopy images reveal that each MNC composed of large number of primary Fe3O4 nanoparticles. The synthesised MNCs show excellent colloidal stability in aqueous phase due to the adsorbed PEG layer. The highest SAR value of 215±10W/gFe observed in 52nm size MNC at a frequency of 126kHz and field of 63kA/m suggest the potential use of these MNC in hyperthermia applications. This study further opens up the possibilities to develop metal ion-doped MNCs with tunable sizes suitable for various biomedical applications using microwave assisted synthesis.

Hydrothermally treated chitosan spontaneously forms water-soluble spherical particles stable at a wide pH range

ABSTRACTThe authors report the spontaneous formation of water-soluble chitosan-tartaric acid (CS-TA) spherical particles. Particles are formed by heating chitosan in the presence of tartaric acid under hydrothermal conditions. Tartaric acid serves as an ionic cross-linker, a depolymerizing agent, and a particle stabilizer in aqueous phase. The CS-TA particles exhibit superior colloidal stability at a wide pH range due to their surface charge tunability, which is due to the colocalization of surface hydroxyl, amine, and carboxyl groups. At physiological pH condition, particles have zwitterionic structure as determined by the zeta potential measurements. Still, CS-TA maintains colloidal stability at neutral pH due to the abundance of surface hydroxyl groups. As a proof-of-concept study, the CS-TA particles were labeled with a model insoluble cargo (fluorescein isothiocyanate [FITC]) to demonstrate their capacity for solubilizing hydrophobic drugs. The CS-TA/FITC conjugates were found to remain well dispersed at neutral pH, while maintaining FITC fluorescence properties.