Cumulative Release Rate Research Articles

αvβ3 Receptor-targeted acid-responsive controlled-release endosome escape doxorubicin-loaded liposomes for A549/ADR treatment

The emergence of liposomes has provided a breakthrough for the clinical use of highly toxic chemotherapeutic drugs. However, the clinical effects of conventional drug-loaded liposomes are unsatisfactory due to the lack of specific targeting of cancer cells and the inability to achieve endosome escape and controllable release in vivo. In this paper, a cRGD-PEOz-Hz-DOB (cPzD) molecule with specific targeting, endosomal escape, and endogenous acid-sensitive controlled release ability was creatively designed and synthesized to prepare drug-loaded liposomes cPzDGX encapsulating the anticancer drug Doxorubicin (DOX) in order to enhance the anticancer performance of DOX. The study found that the hydrazone bond in cPzD reached a breakage rate of 42% within 48 h at pH 5.0, so the cumulative release rate of cPzDGX at pH 5.0 for 48 h was as high as 82.9%, which was 22.5% higher than that at pH 7.4. Moreover, the uptake of cPzDGX in A549/ADR cells was increased by 62% at 2 h, and the expression of the green fluorescent protein gene EGFP was also increased by 36% relative to the targeting control group, indicating that cRGD modification could effectively improve the targeting ability of liposomes to cancer cells. In addition, it was demonstrated that PEOz modification could help drug carriers achieve endosome escape because the green fluorescent protein expression in the PEOz-modified liposome group was 60.5% higher than that in the PEG-modified group. Finally, the cell viability of the cPzDGX group decreased by 17.2% relative to the free DOX group when the DOX concentration was 1 μg/mL in the cytotoxicity assay, and the diameter reduction of 3D tumor MCs increased by 34.4%. And cPzDGX could effectively enhance the permeability of free DOX to solid tumors. The above results indicate that the DOX-loaded liposomes cPzDGX we designed have great prospects for the accurate and efficient treatment of cancer.

Effects of Tolerant Nanoparticles Loaded with Various Regulatory Molecules on the Development of Experimental Autoimmune Encephalomyelitis

This research investigated the effects of tolerating nanoparticles (tNPs) loaded with multiple regulatory molecules on progression of experimental autoimmune encephalomyelitis (EAE). The polylactic acid-glycolic acid copolymer (PLGA), multiple regulatory molecular fragments (Fc) (programmed death receptor ligand 1-Fc (PD-L1-Fc), CD47-Fc), transforming growth factor (TGF-β1), and multiple oligodendrocyte glycoprotein (MOG) antigen peptides (p-MOG) were selected to prepare the tNPs (MRM-tNPs) loaded with various regulatory molecules. Then, the MRM-tNPs were applied in MOG35-55 polypeptide-induced EAE mouse model. According to the treatment methods, the mice were rolled into a group A (BS therapeutic agent), a group B (no-load-NPs), a group C (MOG-tNPs), and a group D (MRM-tNPs). The therapeutic effects were evaluated by the inflammatory infiltration degree (IID), demyelination loss degree (DLD), and apoptosis rate (AR) of CD4+ and CD8+ T cells. The Results showed that the encapsulation rate (ER) of TGF-β1 was 87.65%, and its cumulative release rate (RR) was 58.22%. There were obvious fluorescence signals on MRM-tNPs, MRM-tNPs without PD-L1, and MRM-tNPs without CD47. The neurological function (NF) score in the group D after MRM-tNPs treatment was less than 2 points (P <0.05). The scores of IID and DLD in the brain and spinal cord (SC) of EAE mice in the group D were much lower to those in groups A, B, and C, and the ARs of CD4+ and CD8+ T cells were higher (P <0.05). In conclusion, the tNPs loaded with various regulatory molecules can promote the apoptosis of antigen-specific T cells (AST) and reduce the infiltration and demyelination of inflammatory cells, thus alleviating the EAE.

Folic acid conjugated palygorskite/Au hybrid microgels: Temperature, pH and light triple-responsive and its application in drug delivery

Herein, folic acid conjugated poly (NIPAM-co-functional palygorskite-Au-co-acrylic acid) (FA-PNFA) hybrid microgels were fabricated by emulsion polymerization. The introduction of acrylic acid can increase the low critical solution temperature (LCST) of FA-PNFA from 36 °C at pH 5.5–42 °C at pH 7.4. Doxorubicin hydrochloride (DOX) was chosen as the load drug, the results show that the DOX release behavior is driven by temperature, pH and light. Cumulative drug release rate can reach 74 % at 37 °C and pH 5.5 while only 20 % at 37 °C and pH 7.4, which effectively avoided the early leakage of the drug. In addition, by exposing FA-PNFA hybrid microgels to laser irradiation, the cumulative release rate was increased by 5 % compared to the release rate under dark conditions. Functional palygorskite-Au as physical crosslinkers not only improves the drug loading content of microgels but also promotes the release of DOX through light drive. Methyl thiazolyl tetrazolium bromide (MTT) assay demonstrated that the FA-PNFA are nontoxic up to 200 μg mL−1 towards 4T1 breast cancer cell. Meanwhile, DOX-loaded FA-PNFA show more significant cytotoxicity than the free DOX. Confocal laser scanning microscope (CLSM) revealed that the DOX-loaded FA-PNFA could be efficiently taken by 4T1 breast cancer cells. FA-PNFA hybrid microgels not only improve the LCST of PNIPAM, but also endow the microgels with photostimulation responsiveness, which can release drugs in response to the triple stimulation response of temperature, pH and light, thus effectively reducing the activity of cancer cells, making them more promising for wider medical applications.

PH responsive mesoporous silica as a carrier for controlling doxorubicin hydrochloride delivery

A stimuli-responsive drug carrier (MSNs@P(AA-co-DMAEMA)) with a core-shell structure was constructed using double-bond modified mesoporous silica nanoparticles as a matrix and acrylic acid (AA) and dimethylaminoethyl methacrylate (DMAEMA) as pH-responsive monomers. The structure and properties of the (MSNs@P(AA-co-DMAEMA)) were analyzed by FTIR, TGA, SEM, TEM, XRD, XPS and BET. Adriamycin hydrochloride (DOX) was used as a drug model to investigate the adsorption and release ability of the (MSNs@P(AA-co-DMAEMA)). The adsorption performance tests showed that the drug loading and encapsulation rates were 7.63% and 80.98% at 25 °C, respectively. The drug release results in vitro showed that the cumulative drug release rate of the carrier reached 45.22% at pH 5.5 environment, which was 2.16 times higher than that at pH 7.4, with obvious pH responsiveness. The hemolysis assay demonstrated that the carrier has good biocompatibility.

PH and amylase dual stimuli-responsive electrospinning membrane for smart releasing thymol to control melon Rhizopus stolonifer

Antimicrobial active packaging was limited by the inability to release the antimicrobial agents at the required location, required time, and required quantity. Hence, it is necessary to develop smart release active packaging material that can on-demand release antimicrobial agents according to the storage microenvironment. In this work, a pH and amylase dual responsive release membrane (THY@PLA-COS-DAS) was designed by grafting dialdehyde starch (DAS) onto positively charged chitosan oligosaccharide-modified electrospinning porous poly (lactic acid) (PLA) nanofiber via Schiff base bond. The dialdehyde starch as the smart gatekeeper for on-demand releasing thymol had not only glycosidic bonds that could be hydrolyzed by amylase but also Schiff base bonds that formed with PLA-COS and were sensitive to acidic pH. And the cumulative release rate confirmed that the THY@PLA-COS-DAS could respectively release 78.1% and 98.6% of thymol after 120 h at pH 5.0 or 2 mg/mL glucoamylase conditions. More importantly, the secretion assay demonstrated that Rhizopus stolonifer (R. stolonifer) could secrete acid and amylase, which respectively facilitate the breaking of Schiff base bond and glycosidic bond, thus allowing smart release thymol in response to changes in the storage microenvironment. Meanwhile, THY@PLA-COS-DAS showed a 94.5% inhibition rate against R. stolonifer. More importantly, the biocompatible THY@PLA-COS-DAS could considerably maintain the melon's appearance and hardness compared with the control group. Thus, this pH and amylase dual responsive release nanofiber membrane achieved the sustainable on-demand release of antimicrobial agents to cost-effectively inhibit spoilage microorganisms and had significant potential in innovative antimicrobial active packaging materials.

Preparation and evaluation of sustained release pirfenidone-loaded microsphere dry powder inhalation for treatment of idiopathic pulmonary fibrosis

Pirfenidone (PFND) is a recommended oral drug used to treat idiopathic pulmonary fibrosis, but have low bioavailability and high hepatotoxicity. The study, therefore, seeks to improve the therapeutic activities of the drug via increased bioavailability and reduced associated side effects by developing a novel drug delivery system.The electrostatic spray technology was used to prepare a sustained release pirfenidone-loaded microsphere dry powder inhalation with PEG-modified chitosan (PFND-mPEG-CS-MS). The entrapment efficiency, drug loading, and in vitro cumulative drug release rate (at 24 h and with a sustained release effect) of PFND-mPEG-CS-MS were 77.35±3.01%, 11.45±0.64%, and 90.4%, respectively. The Carr's index of PFND-mPEG-CS-MS powder was 17.074±2.163% with a theoretical mass median aerodynamic diameter (MMADt) of 0.99±0.07 μm, and a moisture absorption weight gain rate (Rw) of 4.61±0.72%. The emptying rate, pulmonary deposition rate (fine particle fraction) and actual mass median aerodynamic diameter (MMADa) were 90%∼95%, 48.72±7.04% and 3.10±0.16 μm, respectively. MTT bioassay showed that mPEG-CS-MS (200 μg/mL) had good biocompatibility (RGR = 90.25%) and PFND-mPEG-CS-MS (200 μg/mL) had significant inhibitory activity (RGR = 49.82%) on fibroblast growth. The pharmacokinetic data revealed that the t1/2 (5.02 h) and MRT (10.66 h) of PFND-mPEG-CS-MS were prolonged compared with the free PFND (t1/2, 1.67 h; MRT, 2.71 h). The pharmacodynamic results also showed that the formulated-drug group had slight pathological changes, lower lung hydroxyproline content, and reduced hepatotoxicity compared with the free-drug group. The PFND-mPEG-CS-MS further significantly down-regulated TGF-β cytokines, Collagen I, and α-SMA protein expression levels compared with the free drug. The findings indicated that the PFND-mPEG-CS-MS had a good sustained release effect, enhanced bioavailability, decreased toxicity, and increased anti-fibrotic activities.

A study on puerarin in situ gel eye drops: Formulation optimization and pharmacokinetics on rabbits by microdialysis

Puerarin (PUE), an isoflavonoid isolated from Pueraria lobata (Willd) Ohwi root, is a β-adrenergic receptor inhibitor used in treating glaucoma. The concentration range of gellan gum was determined based on the formulation viscosity and gelling capacity. PVP-K30 and gellan gum were used as variables, with the viscosity of formulation: STF = 40: 21, the 4 h permeation rate of rabbit isolated sclera, and 2 h in vitro release rate as response values. The JMP software was used to optimize the results, presenting that gellan gum was the main factor influencing viscosity. The in vitro release and permeation rate were primarily influenced by PVP-K30. The optimal prescription was 0.45% gellan gum and 6.0% PVP-K30. The in vitro release and permeation characteristics of puerarin in situ gel (PUE-ISG) were investigated using PUE solution as a control. The dialysis bag method results indicated that the release of the solution group leveled off after 4 h, while the PUE-ISG group had been continuously releasing. However, the cumulative release rates of the two were no longer significantly different at 10 h. The cumulative permeation rates of the ISG and solution groups were not significantly different (P > 0.05) in the rabbit isolated sclera. The apparent permeability Papp and steady-state flux Jss of PUE-ISG were 0.950 ± 0.059 cm/h and 9.504 ± 0.587 mg·(cm·h), respectively. A sensitive and stable HPLC-MS/MS analytical method for quantifying aqueous humor concentrations of PUE was validated. A microdialysis technique was successfully used in the aqueous humor pharmacokinetics study to sample aqueous humor from rabbit eye continuously. The results revealed that PUE-ISG significantly increased the drug concentration in the aqueous humor, with Cmax and AUC(0-t) 3.77 and 4.40 times higher than those of the solution group, respectively. Tmax was also significantly prolonged, indicating good prospects for clinical application. The developed PUE-ISG preparation has the characteristics of rapid drug release and sustained permeation, and increase the drug concentration in aqueous humor, with all inactive ingredients remaining within the maximum allowable limits recommended by the FDA guideline.

Preparation of pH/Light dual-responsive biocompatible polymer micelles: Application to curcumin delivery

Polymer micelles play an important role in the research of drug delivery system because of their nano-size, unique “core-shell” structure and surface modifiability. A pH/photosensitive drug carrier, PEG-PDMAEMA-PNBAE, was synthesized by atom transfer radical polymerization (ATRP) using hydrophilic poly (N, N dimethylaminoethyl methacrylate) (PDMAEMA) as the pH-responsive chain segment and hydrophobic poly (o-nitrobenzyl acrylate) (PNBAE) as the light-responsive chain segment. The molecular and structural characteristics of the polymer were spectroscopically characterized with Fourier transform infrared spectrometer (FT-IR), Nuclear magnetic resonance hydrogen spectrum (1H NMR) and Gel permeation chromatography column (GPC). The morphology and size of micelles were observed by Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The stability of micelles was detected by Laser particle size analyzer (DLS). The Critical micelle concentration (CMC) of the polymer was analyzed by Fluorescence spectrophotometer (Flu), and the photosensitivity of the micelles was determined by Ultraviolet–visible spectrophotometer (UV). The results showed that the synthesized polymers could self-assemble into homogeneous and stable spherical micelles and their particle size was about 100 nm with effective light sensitivity. Curcumin (Cur) was used as a model drug to investigate the adsorption and release abilities of the micelles. The adsorption performance test of the polymeric micelles showed an encapsulation rate of 77.82% and a drug loading capacity of 13.46%. In vitro drug release results showed cumulative drug release rates of 31.79% and 46.55% at pH 5.5 and pH 5.5+UV, indicating the dual pH and light responsiveness of the synthesized carrier. The in vitro hemolysis and cytotoxicity test demonstrated that the carrier has good biosafety.

Schiff base synergized with protonation of PEI to achieve smart antibacteria of nanocellulose packaging films

Microbial growth and reproduction can cause food spoilage. Developing the controlled release packaging films for food is an ideal solution. In this study, polyethyleneimine (PEI) was grafted to cellulose nanofibers (CNF) films by Schiff base, and when the CNF/PEI films were stimulated by pH, PEI released from the CNF/PEI films due to Schiff base hydrolysis, improving the antibacterial efficiency of PEI. Stimulated by acid with pH of 4, the PEI cumulative release rate of the CNF/PEI800 and the CNF/PEI2000 films reached to 92.90 % and 87.28 %, respectively. At the same time, the amino groups of PEI protonated by obtaining H+, the charge density increased, and PEI molecular chains extended, enhancing the antibacterial activity of films. The Zeta potential value on the surface of the CNF/PEI film increased with the decrease of pH value. Schiff base synergized with protonation of PEI to achieve smart antibacteria of CNF packaging films. The antibacterial rates of the film against L. monocytogenes and E. coli were 94.7 % and 90.6 % at pH 4, but 29.5 % and 23.6 % at pH 8, respectively. The developed films also had good barrier properties of oxygen, visible light and mechanical properties, and had an attractive application prospect in food preservation to control release of antibacterial agent.

Preparation and Application of a Natural Microspheric Soil Conditioner Based on Gelatin, Sodium Alginate, and Zeolite

In this work, a type of natural microspheric soil conditioner, PZ(Fe)/GL-SA-Urea, was prepared by emulsion cross-linking and sharp-hole coagulation bath methods. Gelatin (GL) and sodium alginate (SA) were selected as the outermost shell, and the prepared FeOOH was loaded on pickling zeolite (PZ) to improve the loading ratio of urea. The embedding performance and sustained release behavior of the microspheres showed that when the concentration of urea was 1.5%, the embedding rate reached 37.63%, and the cumulative release rate reached 68% within 100 h, indicating that the microsphere had good encapsulation and sustained release abilities. In addition, the water retention and swelling behaviors of the microspheres can be obtained by controlling the content of added GL. Furthermore, antibacterial and planting experiments revealed that the microspheres had excellent antibacterial effects and can effectively improve soil quality and promote crop growth. Therefore, the PZ(Fe)/GL-SA-Urea microsphere soil conditioners possess good application properties and provide fresh solutions to improve soil quality and raise crop yields.

Green construction and release mechanism of lignin-based double-layer coated urea

BackgroundLignin played an important role in the establishment of coated fertilizers coating material as a substitute for petrochemical raw materials. However, so far, the lignin-based coated fertilizers was limited in only the poor slow-release performance. To achieve good slow-release performance of lignin-based coated fertilizers, hydrophilic of lignin need to be resolved to establish an green and better controllable lignin-based coated fertilizers.ResultsIn the study, a novel green double layer coating with lignin-based polyurethane (LPU) as the inner coating and epoxy resin (EP) as the outer coating was effectively constructed for coated urea. Fourier transform infrared spectra confirmed that lignin and polycaprolactone diol successfully reacted with Hexamethylene diisocyanate. The loss weight and water contact angle (WCA, 75.6–63.6°) of the LPUs decreased with the increased lignin content. The average particle hardness of the lignin-based double-layer coated urea (LDCU) first increased from 58.1 N (lignin of 30%) to 67.0 N (lignin of 60%), but then decreased to 62.3 N (lignin of 70%). The release longevity of the coated urea was closely related to the preparation parameters of the coating material. The optimal cumulative nutrient release rate (79.4%) of LDCU was obtained (lignin of 50%, –CNO/–OH molar ratios of 1.15, EP of 35%, and coating ratio of 5%). The aggregates of hydrone on the LDCU caused the dissolution and swelling of nutrients, and then the diffusion of nutrients through the concentration gradient.ConclusionsA though the nutrient release of the LDCUs was affected by many factors, the successful development of the LDCUs will help improve the rapid development of the coated fertilizer industry.

ROS-responsive modified chitosan oligosaccharide nanocapsules for improving pesticide efficiency and intelligent release.

Some traditional pesticide formulations are inefficient, leading to excessive use and abuse of pesticides, which in turn effects environment. Intelligent release pesticide formulations are ideal for improving pesticide utilization and persistence while reducing environmental pollution. We designed a benzil-modified chitosan oligosaccharide (CO-BZ) to encapsulate avermectin (Ave). Ave@CO-BZ nanocapsules are prepared based on a simple interfacial method via cross-linking of CO-BZ with diphenylmethane diisocyanate (MDI). The Ave@CO-BZ nanocapsules have an average particle size of 100 nm and exhibited a responsive release performance for ROS. The cumulative release rate of nanocapsules at 24 h with ROS increased by about 11.4% compared to that without ROS. The Ave@CO-BZ nanocapsules displayed good photostability. Ave@CO-BZ nanocapsules can penetrate root-knot nematodes more easily and exhibited better nematicidal activity against root-knot nematodes. The pot experiment showed that the control effect of Ave CS at low concentration was 53.31% at the initial stage of application (15 d), while Ave@CO-BZ nanocapsules was 63.54%. Under the same conditions, the control effect of Ave@CO-BZ nanocapsules on root-knot nematodes was 60.00% after 45 days of application, while Ave EC was only 13.33%. The acute toxicity experiments of earthworms showed that the toxicity of nanocapsules was significantly lower than that of EC. The ROS-responsive nanocapsules can improve the utilization of pesticides and non-target biosafety. This modified chitosan oligosaccharide has great potential as a bio stimuli-responsive material, and this simple and convenient method for preparing Ave@CO-BZ nanocapsules provides a direction for the effective utilization of pesticides. © 2023 Society of Chemical Industry.

Preparation of Nanodiamond‐Fucoxanthin and Its Application as a Nanodrug Delivery System

AbstractNanodiamonds (NDs) are advantageous for targeted cancer treatment with payload medications due to their good biocompatibility. Herein, a nanodrug delivery system, ND‐fucoxanthin (ND‐FX), was generated by combining FX and acyl chloride‐functionalized NDs, which were created by dispersing and surface‐modifying NDs. The structure and characteristics of NDs were examined via X‐ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. Subsequently, the drug‐loading and ‐release rates of ND‐FX under different pH conditions were calculated using ultraviolet‐visible spectrophotometeric analysis. The drug‐loading rate of the ND‐FX system was 13.17 %; release rate of FX at pH 7.4 and 6.5 was 27.79 % and 54.65 %, respectively; and cumulative release rate of ND‐FX reached 79.98 % over a release duration of 72 h at pH 5.0. Meanwhile, in vitro cytotoxicology experiments demonstrated that ND‐FX effectively inhibited the activity of HeLa and HepG2 cells. These results demonstrate the potential value of NDs in the field of nanodrug delivery applications.

Preparation of resveratrol-loaded ethyl cellulose microspheres via foam-transfer and its application performances

Resveratrol (Res) has been widely used in personal-care and pharmaceutical products due to its anti-oxidant, anti-inflammatory, cardioprotective and anti-cancer properties. However, the direct application of Res as functional additives have been limited due to its insolubility and instability. In this work, Res is loaded on the biodegradable ethyl cellulose (EC) carrier to prepare highly porous EC/Res microspheres via a foam-transfer method to understand the sustained release and the degradation property. The experimental results show that when the PVA concentration = 2.5 wt%, the stirring rate = 600 rpm, the oil/water (O/W) ratio = 1:2, the polymer concentration = 1:25, the heating rate = 0.33 °C/min, and the viscosity of EC = 90 ~ 110 mpa.s, the EC/Res microspheres are obtained with a yield up to 80.70 wt% and an encapsulation efficiency of 73.89% via the batch-process; the EC/Res microspheres are further produced continuously with a higher encapsulation efficiency of 90.63% with a yield of 85.58 wt%. The EC/Res microsphere reaches a cumulative release rate up to 91.97 wt% in the phosphate buffer solution (PBS) at pH = 5.0 under 45 °C for 120 h. After the EC/Res microspheres degraded in PBS (pH = 7.4) for 45 days, the hardness decreased from 12.01 ± 0.56 MPa to 4.02 ± 0.45 MPa. This work thus provides a practical solution for Res’s application as sustained release functional additives.

Preparation, characterization and performance analysis of fosthiazate/expanded perlite sustained-release pesticides

The development of a pesticide-loading system that combines high drug loading and good sustained-release performance is an effective way to reduce pesticide losses and improve utilization of pesticides. In this study, modified waste soybean oil (MSO) and polymethylene polyphenyl polyisocyanate (PM200) were used as raw materials to prepare PM200-MSO. Then, coated fosthiazate/expanded perlite sustained-release pesticides (cFOS/EP) were prepared by disc granulation principle with expanded perlite (EP) as carrier, fosthiazate (FOS) as model pesticide and PM200-MSO as coating material. The results showed that, in PM200-MSO, the –OH of MSO reacted with the –NCO group of PM200 to form carbamate. The surface contact angle of PM200-MSO decreased as the amount of MSO increased. When the amount of PM200 was not less than 50%, FOS leakage from EP was prevented. The pesticide loading (PL) of four pesticides (FOS/EP, cFOS/EP-0, cFOS/EP-1, cFOS/EP-3) was greater than 365.00 mg/g, and kinetic studies showed that FOS release from four pesticides was controlled by diffusion. cFOS/EP-1 had the best sustained-release performance, and its stability at pH5 was better than that at pH7, and the FOS release rate was pH5>pH7, the cumulative release rate (Ri) at 200 h were 58.22% and 46.99%, respectively. The FOS release from cFOS/EP-1 belonged to Fickian diffusion at pH5. When pH = 7, it belonged to non-Fickian diffusion, which was dominated by diffusion and complementary by dissolution. SEM observation confirmed the presence of large protrusions and depressions on the surface of cFOS/EP-1, internal cracks, and slight dissolution of its film structure at pH7.

Preparation of Novel Biodegradable Polymer Slow-Release Fertilizers to Improve Nutrient Release Performance and Soil Phosphorus Availability.

Inspired by the gradual collapse of carbon chain and the gradual release of organic elements into the external environment during the degradation of biodegradable polymers, a novel biodegradable polymer slow-release fertilizer containing nutrient nitrogen and phosphorus (PSNP) was prepared in this study. PSNP contains phosphate fragment and urea formaldehyde (UF) fragment, which are prepared by solution condensation reaction. Under the optimal process, the nitrogen (N) and P2O5 contents of PSNP were 22% and 20%, respectively. The expected molecular structure of PSNP was confirmed by SEM, FTIR, XRD, and TG. PSNP can release N and phosphorus (P) nutrients slowly under the action of microorganisms, and the cumulative release rates of N and P in 1 month were only 34.23% and 36.91%, respectively. More importantly, through soil incubation experiment and leaching experiment, it was found that UF fragments released in the degradation process of PSNP can strongly complex soil high-valence metal ions, thus inhibiting the phosphorus nutrient released by degradation to be fixed in the soil and ultimately effectively increasing the soil available P content. Compared with ammonium dihydrogen phosphate (ADP), a small molecule phosphate fertilizer that is easily soluble, the available P content of PSNP in the 20-30 cm soil layer is almost twice that of ADP. Our study provides a simple copolymerization method to prepare PSNP with excellent slow-release N and P nutrients, which can promote the development of sustainable agriculture.

A Supramolecular Nanovehicle Featuring a pH/Enzyme Co-Response for Targeted Delivery of the Antitumor Compound.

Triptolide (TPL) has gained much attention as an antitumor compound with potential applications. However, TPL suffers from low bioavailability, severe toxic side effects, and limited targeted uptake by tumor cells, thus restricting the conversion of its clinical application. Here, a supramolecular nanovehicle, named TSCD/MCC NPs, featuring pH/AChE co-response was designed and prepared for loading, delivery, and targeted release of TPL. The cumulative release rate of TPL from TPL@TSCD/MCC NPs reached ∼90 % within 60 h at pH 5.0 and AChE co-stimulation. Bhaskar model is used to study TPL release procedure. In cell experiments, TPL@TSCD/MCC NPs showed high toxicity to the four tumor cells lines A549, HL-60, MCF-7, and SW480, and favorable biosafety to normal cells BEAS-2B. Furthermore, TPL@TSCD/MCC NPs containing relatively small amounts of TPL presented similar apoptosis rates to those of intrinsic TPL. We anticipate that TPL@TSCD/MCC NPs may facilitate the conversion of TPL into clinical applications through further studies.

Stimulus-responsive starch-based nanocapsules for targeted delivery and antibacterial applications

Polysaccharide materials have attracted a widespread interest in the biomedical materials field due to their non-toxic, biocompatible and biodegradable properties. In this research, starch was modified with chloroacetic acid, folic acid (FA) and thioglycolic acid and then starch-based nanocapsules loaded with curcumin (FA-RSNCs@CUR) were prepared by the convenient oxidation method. The nanocapsules were prepared with stable particle size distribution of 100 nm. In the drug release test simulating the tumor microenvironment in vitro, the cumulative CUR release rate at 12 h was 85.18 %. Due to FA and FA receptor mediation, it only took 4 h for FA-RSNCs@CUR to achieve internalization by HeLa cells. In addition, cytotoxicity confirmed that starch-based nanocapsules have good biocompatibility as well as protection of normal cells in vitro. And FA-RSNCs@CUR showed certain antibacterial properties in vitro. Therefore, FA-RSNCs@CUR has good potential for future applications in food preservation and wound dressing, and so on.

Dry Nutrition Delivery System Based on Defatted Soybean Particles and Its Application with β-Carotene.

Many nutrition delivery systems (NDSs) have been developed for the encapsulation, protection, and delivery of bioactive compounds, such as β-carotene. Most of those systems were prepared in solution, which is inconvenient for transportation and storage in the food industry. In the present work, we constructed an environmentally friendly dry NDS based on defatted soybean particles (DSPs) by milling a β-carotene-DSP mixture. The loading efficiency of the NDS reached 89.0%, and the cumulative release rate decreased from 15.1% (free β-carotene) to 6.0% within 8 h. The stability of β-carotene in the dry NDS was found to have increased in a thermogravimetric analysis. Stored for 14 days at 55 °C or under UV irradiation, the retaining rates of β-carotene in the NDS increased to 50.7% and 63.6%, respectively, while they were 24.2% and 54.6% for the free samples. The bioavailability of β-carotene was improved by the NDS too. The apparent permeability coefficient of the NDS reached 1.37 × 10-6 cm/s, which is 12 times that of free β-carotene (0.11 × 10-6 cm/s). Besides being environmentally friendly, the dry NDS can facilitate carriage, transportation, or storage in the food industry, and similar to other NDSs, it improves the stability and bioavailability of nutrients.

Fast-release kinetics of a pH-responsive polymer detected by dynamic contact angles.

Polymers conjugated with active agents have applications in biomedicine, anticorrosion, and smart agriculture. When the active agent is used as a drug, corrosion inhibitor, or pesticide, it can be released upon a specific stimulus. The efficiency and the sustainability of active agents are determined by the released kinetics. In this work, we study the fast-release kinetics of 8-hydroxyquinoline (8HQ) from a pH-responsive, random copolymer of methyl methacrylate and 8-quinolinyl-sulfide-ethyl acrylate [P(MMA-co-HQSEA)] by hydrolysis of the β-thiopropionate groups. We used contact angle measurements of sliding drops as an elegant way to characterize the release kinetics. Based on the results gained from 1H nuclear magnetic resonance measurement, fluorescent intensity measurement, and velocity-dependent contact angle measurement, we found that both the hydrolysis rate and polymer conformation affect the release kinetics of 8HQ from a P(MMA-co-HQSEA) film. Polymer chains collapse and further suppress the release from the inner layer in acidic conditions, while polymer chains in a stretched condition further facilitate the release from the inner layer. As a result, the cumulative release rate of 8HQ is higher in the basic condition than in the acidic condition.