Dendritic Fibrous Nanosilica Research Articles

Cistanche deserticola polysaccharide-functionalized dendritic fibrous nano-silica as oral delivery system for H9N2 vaccine to promote systemic and mucosal immune response.

Most infectious diseases are caused by pathogens that invade the body tissues through mucosal tract. Therefore, it is essential to develop effective vaccines administered through the mucosa as a first-line of defense against major infectious diseases. Oral delivery of vaccines is currently of great interest due to its potential to elicit both mucosal and systemic immune responses, high compliance rate and non-invasive nature. However, their development is limited by the challenging gastrointestinal (GI) environment, the low permeability of the mucus barrier, and the lack of effective and safe mucosal adjuvants. Currently, nanoparticle-based strategies show significant potential for improving oral vaccine delivery systems. Herein, the dendritic fibrous nano-silica (DFNS) grafted with Cistanche deserticola polysaccharide (CDP) nanoparticles (CDP-DFNS) were developed for oral delivery of H9N2 antigen. CDP-DFNS induced the activation of macrophages, thereby enhancing antigen uptake in vitro. Additionally, CDP-DFNS/H9N2 significantly activated the dendritic cells (DCs) in Peyer's patches (PPs), and T/B cells in mesenteric lymph nodes (MLNs). Moreover, CDP-DFNS/H9N2 enhanced the HI titers and levels of H9N2-specific antibody IgG, secretory IgA (SIgA) and H9N2-specific IgA in intestinal and respiratory mucosa, as well as Th-associated cytokines. Our results indicate that CDP-DFNS could be a promising oral vaccine adjuvant delivery system.

Aptasensing of rivaroxaban in human plasma using KCC-1-NH-CS2 modified conductive nano-ink: A new biosensor

An innovative paper-based electrochemical aptasensor has been developed for the detection of Rivaroxaban (RIV) in human plasma samples. The sensor is fabricated using a novel prob by encapsulating aptamer-aminated on dendritic fibrous nano-silica (KCC-1-NH-CS2) particles. The prob is then immobilized on the functionalized silver nano-ink electrode.. The resulting redox reaction on the prob was subsequently evaluated using square wave voltammetry, differential pulse voltammetry, and chronoamperometry. Under optimized condition and using a label-free strategy, the aptasensor exhibited suitable sensitivity and specificity for detecting RIV with a linear range of 10 to 1000 nM and a lower limit of quantification (LLOQ) of 10 nM. The engineered aptasensing platform shows great potential for the fabrication of other cost-effective, sensitive, and portable biosensors for the pharmaceutical and biomedical analysis.

Synthesis of carrageenan/DFNS composite and its application in the esterification of levulinic acid with alcohols

The surface acidity of dendritic fibrous nano-silica (DFNS) was modified by a k-carrageenan biopolymer having sulfonic acid functional groups. The composite was used as a solid acid catalyst in the Fischer esterification reaction to convert levulinic acid (LA) to alkyl levulinates. The samples were characterized by analytical and instrumental techniques such as FT-IR spectroscopy, X-ray diffraction (XRD), N2 adsorption–desorption analysis, FESEM, and TEM. By using different alcohols including a short chain (ethanol), a medium chain (n-butanol), and a long chain (n-hexanol), the impact of various parameters on the esterification reaction was investigated. Under the optimum reaction conditions including 6 h as the reaction time, 10 mg catalyst amount, 12:1 ethanol: LA ratio, and 150 °C as the reaction temperature a 61 % ethyl levulinate was obtained. The selected catalyst was recycled and regenerated for use in successive runs without worthy loss in its activity.

Interplay of physical and textural properties in porous, nanostructured hard‑carbons as electrode materials for non-Faradic energy storage devices

This work presents a systematic investigation on the non-Faradic energy storage ability of non-graphitizable, porosity engineered hard‑carbon nanostructures as electrode materials. The persistent challenge of inducing and tuning porosity in hard‑carbon nanostructures is overcome here, by utilizing dendritic fibrous nano silica (DFNS) as a sacrificial template for uniform and conformal deposition of carbon through thermal chemical vapor deposition, leading to the formation of porosity tuned, nanostructured hard‑carbon florets (NCF). This strategy enables precisely crafted six varieties of NCF with varying yet monodisperse dimensions (NCF 90, NCF 350, NCF 366, NCF 430, NCF 540 and NCF 600), SSA (494–719 m2/g) and textural features such as pore volume (0.67–1.24 cm3/g) and pore diameter (3.83–5.65 nm). In contrast to current understanding, NCF 366 with defect length of 16 nm, defect density of 2.65 × 1011 cm−2, micro- to mesoscale pore ratio of 0.16 and specific surface area of 535 m2/g achieves the highest energy density of 14.6 Wh/kg and power density 10.0 kW/kg, when compared to NCF 90 with higher SSA (719 m2/g) and pore volume (1.24 cm3/g). Thus, this work manifests the critical contributions of tuning the pore structures and optimizing the relative contributions from multi-scale pore structures to achieve high-performing energy storage devices.

Hydrogenation of Ethyl Levulinate to Gamma-Valerolactone with Formic Acid and a Palladium–Manganese Catalyst Immobilized on Dendritic Fibrous Nanosilica (DFNS)

Hydrogenation of Ethyl Levulinate to Gamma-Valerolactone with Formic Acid and a Palladium–Manganese Catalyst Immobilized on Dendritic Fibrous Nanosilica (DFNS)

Collaborative adsorption and photocatalytic degradation of high concentration pharmaceutical pollutants in water using a novel dendritic fibrous nano-silica modified with chitosan and UiO-66

This study presents a novel hybrid mesoporous material for degrading drug pollutants in water. The hybrid materials, derived from UiO-66 metal-organic framework and chitosan, coated on nano-silica, showed excellent drug adsorption through hydrogen-bonding interactions and efficient photodegradation of antibiotics. The hybrid material's enhanced conductivity and reduced band gap significantly improved pollution reduction by minimising electron-hole recombination. This allows for more efficient charge transport and better light absorption, boosting the material's ability to break down pollutants. Structural and morphological analyses were conducted using various techniques, including scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Optimising the adsorption-photodegradation process involved investigating pH, catalyst dose, and radiation time. Non-linear optimisation revealed an efficiency exceeding 85 % for 400 mg/L tetracycline and doxycycline, the model antibiotics. The optimal parameters for maximal elimination were determined as pH = 4.3, hybrid mesosphere dose = 4.0 mg/mL, and radiation time = 10 min. Kinetic studies favored pseudo-second-order diffusion models over pseudo-first-order models. The hybrid mesosphere showed sustained efficiency after three cycles and performed well in real aqueous samples, removing over 80 % of each antibiotic. This study demonstrates the potential of the hybrid mesoporous material for removing pharmaceutical pollutants in water systems.

Designed Nanoarchitectures of a BiOBr/BiOI Nanosheet Heterojunction Anchored on Dendritic Fibrous Nanosilica as Visible-Light Responsive Photocatalysts.

Heterojunctions, particularly those involving BiOBr/BiOI, have attracted significant attention in the field of photocatalysis due to their remarkable properties. In this study, a unique architecture of BiOBr/BiOI was designed to facilitate the rapid transfer of electrons and holes, effectively mitigating the recombination of electron-hole pairs. Accordingly, the BiOBr/BiOI nanosheet heterojunction was anchored on dendritic fibrous nanosilica (DFNS) by the immobilization of Bi2O3 nanodots in DFNS and the subsequent reaction with HBr and then HI vapors at room temperature. The 4 nm-Bi2O3 nanodots acted as a sacrificial template to form BiOX nanosheets by reaction with HX vapors (X = Br, I). The BiOBr/BiOI nanosheet heterojunction with the lateral size remained in the range of 90 to 110 nm and a thickness of 15 nm formed on DFNS, where the BiOBr:BiOI ratio in the product was controlled by the exposure time to HX vapors. The reaction sequence (HBr → HI vapors) was a key for the formation of BiOBr/BiOI nanosheet heterojunction with controlled composition. When the reaction of Bi2O3 nanodots with HI vapor was performed in the reverse sequence (HI→ HBr), the substitution of I- with Br- occurred to form BiOBr sheets on DFNS. The BiOBr/BiOI nanosheet heterojunction anchored on DFNS was used as a visible-light-driven photocatalyst for the decomposition of benzene in water under solar light, and its activity was superior to that of single BiOX nanosheets on DFNS.

LaFeO3 nanoparticle immobilized on DFNS-graphene oxide for the production of polymer and biopolyurethanes from carbon dioxide

Dendritic fibrous nano silica (DFNS) was functionalized through the utilization of graphene oxide (GO) as a long-lasting anchoring agent. Consequently, the LaFeO3 nanoparticles were evenly spread out without clumping over the DFNS/GO. The supramolecular polymerized GO served the dual purpose of preventing the restacking of graphene sheets and functioned as a supplier of nitrogen to create active sites for the bonding of LaFeO3 nanoparticles. The nitrogen content above the extent of the GO films was modified by LaCl3·7 H2O and Fe(NO3)3·9H2O ions to synthesize LaFeO3 nanoparticles. The catalytic properties of DFNS/GO-LaFeO3 was observed in the reaction between CO2 and oxetane and epoxide, leading to the production of the corresponding polycarbonates. The results indicated that DFNS/GO-LaFeO3 significantly enhanced the efficiency of synthesizing poly(propylene carbonate) and poly(trimethylene carbonate) from carbon dioxide. This approach offers substantial benefits, including high economic efficiency. The union reaction of CO2 and highly substituted epoxides sourced from sustainable sources such as discarded vegetable oils and fatty acids resulted in the production of novel cyclic carbonates of bio-origin. This reaction occurred under gentle and solvent-free conditions using DFNS/GO-LaFeO3 as a catalyst. The DFNS/GO-LaFeO3 exhibited a high capacity for CO2 uptake with exceptionally rapid kinetics. The nanoplate morphology of DFNS/GO-LaFeO3 facilitated the formation of a satisfactory outer layer for carbon dioxide uptake at each metal site. Consequently, the nanoplate morphology of DFNS/GO-LaFeO3 ensured systematic carbon dioxide emission, guaranteeing a complete reaction with the entire sheet and enabling rapid CO2 adsorption kinetics.

Impact of chitosan extracted from shrimp shells on the shrinkage and mechanical properties of cement-based composites using dendritic fibrous nanosilica

Dendritic fibrous nanosilica (DFNS) was functionalized using microcrystalline chitosan, derived from shrimp exoskeletons, to act as a robust anchor, resulting in DFNS@Chitosan. In order to prevent the restacking of chitosan sheets, the supramolecular polymerized chitosan not only served as a spacer but was also incorporated into cement-based composites. The physical-chemical characteristics of DFNS@Chitosan were assessed through various analytical techniques such as TEM, SEM, TGA, FTIR, AFM, XPS, and EDX. The potency and auto-induced contraction of Cement-based composite materials fortified with DFNS@Chitosan were probed. The incorporation of DFNS@Chitosan resulted in an increase in both compressive and interfacial stretching potency of the cement-based composites. Furthermore, the presence of DFNS@Chitosan effectively inhibited the occurrence of auto-induced contraction in the cement-based paste. This research endeavor is anticipated to promote an alternative utilization of DFNS and shrimp waste shells in the development of sustainable building materials.

Pompon Mum-like SiO2/C Nanospheres with High Performance as Anodes for Lithium-Ion Batteries

SiO2 has a much higher theoretical specific capacity (1965 mAh g−1) than graphite, making it a promising anode material for lithium-ion batteries, but its low conductivity and volume expansion problems need to be improved urgently. In this work, pompon mum-like SiO2/C nanospheres with the sandwich and porous nanostructure were obtained by using dendritic fibrous nano silica (DFNS) and glucose as matrix and carbon source, respectively, through hydrothermal, carbonization and etching operations. The influence of SiO2 content and porous structure on its electrochemical performance was discussed in detail. The final results showed that the C/DFNS-6 with a SiO2 content of 6 wt% exhibits the best electrochemical performance as a negative electrode material for lithium-ion batteries due to its optimal specific surface area, porosity, and appropriate SiO2 content. C/DFNS-6 displays a high specific reversible capacity of 986 mAh g−1 at 0.2 A g−1 after 200 cycles, and 529 mAh g−1 at a high current density (1.0 A g−1) after 300 cycles. It also has excellent rate capability, with a reversible capacity that rises from 599 mAh g−1 to 1066 mAh g−1 when the current density drops from 4.0 A g−1 to 0.2 A g−1. These SiO2/C specific pompon mum-like nanospheres with excellent electrochemical performance have great research significance in the field of lithium-ion batteries.

Tribological property of dendritic fibrous nano silica composite particle as lubricant additive

In this study, a novel Dendritic Fibrous Nano Silica (DFNS) solid-liquid composite lubricant additive (DFNS@ILs) was prepared by the simple of bi-continuous microemulsion polymerization and vacuum impregnation adsorption ionic liquids (ILs) method. The microstructure and chemical composition were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The oil lubrication properties of the DFNS@ILs were investigated and the results showed that the DFNS@ILs additive had the most excellent tribological properties when compared to the pure PAO6 oil, commercially available ZDDP and nano-silica. Moreover, DFNS@ILs have long-term stability as lubricant additives. Based on the analysis of the wear surfaces, it is concluded that the excellent performance of DFNS@ILs additive are owing to the synergistic lubrication effect of DFNS and ILs as well as the formation of transfer film, which makes it a promising lubricant material.

Fluorescent dendritic fibrous nanosilica@chitosan porous composite microbeads: Selective and sensitive probes and removal adsorbents for Hg2+/Hg+ ions

Dendritic fibrous nano-silica (DFNS) possesses unique porous structure, making it an outstanding candidate for heavy metal adsorption and separation. It is interesting to introduce natural polymer (chitosan) into DFNS and produce natural materials-based porous DFNS. Initially, in this work, DFNS underwent modification to enlarge size and enrich with -C≡C bonds. And then, NH2-naphthalimide fluorophore was click-reacted with the modified DFNS, forming fluorescent DFNS (FL-DFNS). Eventually, chitosan was integrated into FL-DFNS using diacyl chloride, generating the organic–inorganic fluorescent composite micro-beads (FL-DFNS@CS-3). FL-DFNS acts as a “turn on” sensor for Hg2+/Hg+ ions, showing up to 5 times fluorescence increase. Also, it exhibited effective mercury adsorption. Due to its porous structure, it demonstrated good performance in adsorbing and separating Hg2+/Hg+ ions, achieving removal ratios of 98.8 % and 96.1 %, and adsorption capacities of 196.2 mg/g and 180.4 mg/g, respectively. It reached effective adsorption equilibrium within 15 min and was reusable up to seven times. Overall, this work confirms the practical applicability of FL-DFNS and FL-DFNS@CS micro-beads for identifying and removing Hg2+/Hg+ ions. Further exploration is worthy to explore its potential in environmental science and engineering.

Polydopamine functionalized dendritic fibrous silica nanoparticles as a generic platform for nucleic acid-based biosensing

Accurate and rapid detection of nucleic acid sequences is of utmost importance in various fields, including disease monitoring, clinical treatment, gene analysis and drug discovery. In this study, we developed a "turn-on" fluorescence biosensor that enables simple and highly efficient detection of nucleic acid biomarkers. Our approach involves the utilization of 6-carboxyfluorescein modified single-stranded DNA (FAM-ssDNA) as molecular recognition element, along with polydopamine-functionalized dendritic fibrous nanosilica (DFNS). FAM-ssDNA serves as both specific molecular recognition element for the target analyte and reporter capable of transducing a detectable signal through Watson–Crick base pairing. The polydopamine-functionalized DFNS (DFNS@DA) exhibits strong binding to FAM-ssDNA via polyvalent metal mediated coordination leading to effective quenching by fluorescence resonance energy transfer. In the presence of a complementary target sequence, FAM-ssDNA forms hybridized structure and detaches from DFNS@DA, which causes an increased fluorescence emission. The analytical system based on FAM-ssDNA and DFNS@DA demonstrates exceptional sensitivity, selectivity, and rapid response for the detection of nucleic acid sequences, leveraging the high adsorption and quenching properties of DFNS@DA. For the first proof of concept, we demonstrated the successful detection of microRNA (miR-21) in cancer cells using the FAM-ssDNA/DFNS@DA system. Our results highlight the promising capabilities of DFNS@DA and nucleic acid-based biosensors, offering a generic and cost-effective solution for the detection of nucleic acid-related biomarkers.Graphical abstract

Cistanche deserticola polysaccharide-functionalized dendritic fibrous nano-silica as oral vaccine adjuvant delivery enhancing both the mucosal and systemic immunity

Oral vaccines are a safe and convenient alternative to injected vaccines and have great potential to prevent major infectious diseases. However, the harsh gastrointestinal (GI) environment, mucus barriers, low immunogenicity, and lack of effective and safe mucosal adjuvants are the major challenges for oral vaccine delivery. In recent years, nanoparticle-based strategies have become attractive for improving oral vaccine delivery. Here, the dendritic fibrous nano-silica (DFNS) grafted with Cistanche deserticola polysaccharide (CDP) nanoparticles (CDP-DFNS) were prepared and investigated how to impact the immune responses. CDP-DFNS facilitated the antigen uptake in mouse bone marrow-derived dendritic cells (BMDCs), and induce the activation of DCs in vitro. Furthermore, in vivo experiments, the result showed that the uptake efficiency by Peyer's patches (PPs) of CDP-DFNS/BSA was the best. And CDP-DFNS/BSA then significantly activated the DCs in lamina propria (LP), and T/B cells in PPs and mesenteric lymph nodes (MLNs). Moreover, the memory T cell responses in later period of vaccination was stronger than other groups. In addition, CDP-DFNS/BSA enhanced BSA-specific antibody IgG, IgA production, and SIgA secretion, was effective at inducing a strong mixed Th1/Th2 response and mucosal antibody responses. These results indicated that CDP-DFNS deserves further consideration as an oral vaccine adjuvant delivery system.

An innovative transportable immune device for the recognition of α-synuclein using KCC-1-nPr-CS2 modified silver nano-ink: integration of pen-on-paper technology with biosensing toward early-stage diagnosis of Parkinson's disease.

Parkinson's disease (PD), the second most frequent neurodegenerative illness, is a neurological ailment that produces unintentional or uncontrolled body movements, which should be diagnosed in its early stages to hinder the progression. Monitoring the concentration of α-synuclein (α-Syn) in body fluids can be one of the most efficient ways for PD early detection. In this work, a paper-based electrochemical immunosensor was designed for α-Syn bio-assay in human plasma samples based on encapsulation of the biotinylated antibody on novel dendritic fibrous nanosilica ((KCC-1-nPr-CS2)-Ab). For this purpose, a three-electrode system was prepared using stabilization of silver nano-ink on photographic paper. Then, the (KCC-1-NH-CS2)-Ab was immobilized on its surface and used to detect the target antigen (α-Syn). After characterization of the prepared substrate by FE-SEM and EDS, the redox behavior of the biosensor was evaluated using chronoamperometry techniques. Under optimal experimental conditions and using a label-free strategy, the engineered immunosensor showed a linear relationship between peak current and antigen concentration in the linear range from 0.002 to 128 ng mL-1 with the lower limit of quantification of 0.002 ng mL-1. Moreover, this work involves unprecedented use of conductive nano-inks for the manufacture of α-Syn immunosensor, which is aided by the use of a mesoporous silicate dendrimer in encapsulating the α-Syn antibody, thus offering a robust and simple point-of-care device for early PD diagnosis. The ability of the proposed platform to detect small amounts of α-Syn offers a promising approach to developing low-cost, sensitive, and transportable biosensors for Parkinson's disease screening in its early stages.

Metal-free bi-functional cooperative catalysis: amine and quaternary amine-functionalized dendritic fibrous nanosilica as heterogeneous catalysts for the Henry reaction and CO2 conversion

This study explores amine-functionalized dendritic fibrous nanosilica (DFNS) as a highly efficient, base-free heterogeneous catalyst for nitro-aldol (Henry) condensation and additive-free CO2 utilization, outperforming existing catalysts.

The potential utility of dendritic fibrous nanosilica as an adsorbent and a catalyst in carbon capture, utilization, and storage.

Anthropogenic emissions of greenhouse gases (GHG; e.g., CO2) are regarded as the most critical cause of the current global climate crisis. To combat this issue, a plethora of CO2 capture, utilization, and storage (CCUS) technologies have been proposed and developed based on a number of technical principles (e.g., post-combustion capture, chemical looping, and catalytic conversion). In this light, the potential utility of dendritic fibrous nanosilica (DFNS) materials is recognized for specific CCUS applications (such as adsorptive capture of CO2 and its catalytic conversion into a list of value-added products (e.g., methane, carbon monoxide, and cyclic carbonates)) with the highly tunable properties (e.g., high surface area, pore volume, multifunctional surface, and open pore structure). This review has been organized to offer a comprehensive evaluation of the approaches required for tuning the textural/morphological/surface properties of DFNS (based on multiple synthesis and modification scenarios) toward CCUS applications. It further discusses the effects of such approaches on the properties of DFNS materials in relation to their CCUS performance. This review is thus expected to help develop and implement advanced strategies for DFNS-based CCUS technologies.

Bio-based nanocomposite hydrogels derived from poly (glycerol tartrate) and cellulose: Thermally stable and green adsorbents for efficient adsorption of heavy metals

The eco-friendly polymeric nanocomposite hydrogels were prepared by incorporating dendritic fibrous nanosilica (DFNS) and apple peel (AP) as reinforcements into the crosslinked polymer produced by cellulose (CL) and poly (glycerol tartrate) (TAGL) via gelation method and used for efficient adsorption of Pb2+, Co2+, Ni2+, and Cu2+ metal ions. DFNS and DFNS/TAGL-CL/AP samples were characterized by FESEM, FTIR, TEM, TGA, and nitrogen adsorption/desorption methods. The results of TGA analysis showed that the thermal stability of the prepared hydrogels improved significantly in the presence of DFNS. Both synthetic and environmental parameters were investigated and the adsorption capacity reached 560.2 (pH = 4) and 473.12 (pH = 5) mg/g for Pb2+ and Cu2+ respectively, using initial ion concentration of 200 mg/L. Also, the maximum adsorption capacity was 340.9, and 350.3 mg/g for Co2+ and Ni2+, respectively under optimum conditions (pH = 6, initial ion concentration of 100 mg/L). These experiments indicated that the DFNS/TAGL-CL/AP nanocomposite hydrogel has an excellent performance in removal of Pb2+ and can adsorb this toxic metal in only 30 min while the optimum contact time for other metals was 60 min. Pseudo-second-order and Langmuir models were used to define the kinetic and adsorption isotherms, respectively and thermodynamic studies demonstrated that the adsorption was endothermic for Co2+, Ni2+ and Cu2+, exothermic for Pb2+, and spontaneous in nature for all metal ions. Furthermore, the reusability tests indicated that the hydrogels could maintain up to 93% of their initial adsorption capacity for all metal ions after four cycles. Therefore, the prepared nanocomposite hydrogels can be suggested as efficient adsorbents to remove the toxic metals from wastewater.

Effect of interfacial modification on functional properties of polyethylene and polypropylene—Fibrous silica nanocomposites

AbstractThis paper reports the results of polyethylene (PE) and polypropylene (PP) composites containing 5 and 10 wt.% dendritic fibrous nanosilica (DFNS) synthesized by a hydrothermal process. The objective of this investigation is to provide a better understanding of the relationship between the structure, composition, matrix‐nanofiller interfaces, and the properties of these nanocomposites. These materials have been prepared by twin‐screw extrusion and injection molding. Their structural, thermal, mechanical, rheological, and electrical properties were evaluated, both alone and when combined with an organic compatibilizing agent. Findings have shown that the unique morphology of fibrous silica nanoparticles was preserved and not altered by melt processing, indicating the high thermal and mechanical stability of these fibrous materials. The nanocomposites containing DFNS alone exhibited higher mechanical performances compared to those containing the surface modifier, with no observable effect on their thermal properties. Findings also showed that the interactions between the nanoparticles and polymer may influence the functional properties of the final nanocomposites, and that they are dependent on both the nature of the host polymer along with the presence of the surface modifier agent.Highlights Well‐defined DFNS were successfully prepared. PE and PP based nanocomposites were successfully designed by twin‐screw extrusion. Good interfacial interactions were obtained with PP. Functional properties of the nanocomposites were influenced by the interfacial adhesion.

Delivery of paclitaxel by carboxymethyl chitosan-functionalized dendritic fibrous nano-silica: Fabrication, characterization, controlled release performance and pharmacokinetics

In this study, carboxymethyl chitosan (CMCS) with excellent biocompatibility was used as the “gatekeeper” to design and fabricate a pH-responsive drug delivery system (CMCS-DFNS) as paclitaxel carriers. Characterization results showed that CMCS-DFNS was successfully prepared and the nanocarriers displayed excellent drug loading efficiency of 19.8 %, and the results of the adsorption mechanism revealed that the adsorption of PTX was consistent with the Freundlich isotherm and pseudo-second-order kinetic model. Furthermore, the pH-responsive controlled release behavior at different pH (pH = 7.4, 6.5, and 5.0) was evaluated, and the results demonstrated that the cumulative release at pH 5.0 was 58.8 %, which was 2.7 times higher than that at pH 7.4, suggesting that the carrier exhibited a good pH sensitivity. The results of in vitro cellular experiments further indicated that CMCS-DFNS significantly improved the drug uptake efficiency in breast cancer MCF-7 cells. Importantly, the results of in vivo and cellular pharmacokinetic revealed that CMCS-DFNS can improve the circulation time and enhance the relative bioavailability of paclitaxel. Therefore, the fabricated pH-responsive drug delivery system has potential applications in the delivery of anti-tumor drugs, and provides a new delivery pathway for other compounds with low bioavailability.