Slow Release Behavior Research Articles

Enhanced recovery of phosphorus in sewage sludge-derived biochar with CaCO3: Phosphorus speciation and slow-release phosphorus behavior

The recovery of phosphorus (P) from sewage sludge through pyrolysis is one of the most promising alternatives to alleviate the shortage of P supply in the future. Adding calcium additives is beneficial to the conversion of available P and helps to improve the recovery and utilization efficiency of P in biochar. This study thoroughly examined the influence of CaCO3 on the speciation and slow-release behavior of P in sludge during pyrolysis at 500 and 700 °C. The addition of CaCO3 could enhance the conversion of non-apatite inorganic phosphorus (NAIP) into more accessible apatite phosphorus (AP). We observed that adding CaCO3 (2.5–20 %) to raw sludge at 500 °C increased the proportion of AP in inorganic phosphorus (IP) from 65.2 to 97.3 % but did not increase the concentration of AP, which remained between 31.03 and 31.64 mg/g. At 700 °C, introducing CaCO3 (2.5–20 %) boosted the AP content from 35.08 to 41.38 mg/g and increased the proportion of AP in IP from 67.7 to 98.6 %. Moreover, irrespective of the pyrolysis temperature being 500 °C or 700 °C, the final main form of P in biochar with CaCO3 was Ca5(PO4)3OH, according to experimental characterization results (X-ray photoelectron spectroscopy and X-ray diffraction) and thermochemical calculations. Additionally, the efficacy of citric acid (CA) in releasing biochar-bearing P was tested in a laboratory extraction experiment for 21 days. CaCO3-amended biochar showed a significantly slower total phosphorus (TP) release than the biochar without CaCO3 daily, and the amount of TP decreased with increasing amounts of added CaCO3. The finding of this study indicates that biochar generated by adding 10 % CaCO3 has the highest AP concentration (41.38 mg/g) at 700 °C, and its TP-release efficiency in CA is 0.29–1.98 mg/g in 21 days, which shows remarkable potential as a soil fertilizer with slow P release.

Preparation of slow-release microencapsulated fertilizer-Biostimulation remediation of marine oil spill pollution

Occasional marine oil spills can have considerable negative effects on the environment and economy. Using biotechnology to clean up oil is more reliable and environmentally friendly. Biostimulation can greatly enhance the hydrocarbon degradation activity of native microorganisms. In this study, slow-release microencapsulated fertilizers with alginate and bentonite as base, nitrogen and phosphorus as release elements, and double-coated with ethyl cellulose and vegetable wax were developed for biostimulation to improve the degradation of petroleum hydrocarbons. The prepared material had a macroporous structure resembling a honeycomb, in which nitrogen and phosphorus elements were scattered according to results from scanning electron microscopy and element mapping images. Additionally, the success load of nitrogen and phosphorus was further verified by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The effects of additional quantities of bentonite on the slow-release of nutrients were examined, and the findings indicated that the slow-release process benefited from the rise in bentonite. More excellent slow-release behavior was obtained after coating material, and the release process conformed to the Fickian diffusion model. The results of biostimulation repair experiments of oil spill show that the slow-release microencapsulated fertilizer can improve the degradation effect of petroleum hydrocarbons, particularly high molecular weight polycyclic aromatic hydrocarbons (PAHs). Further researches on the microbial community revealed that biostimulation altered microbial community structure following the oil spill, making Cycloclasticus prevalent, which in turn improved native microorganisms' ability to degrade PAHs. The alginate/bentonite composite aerogels were promising to be used as biocompatible carriers for microbial nutrition delivery.

Stability of glycosylated complexes loaded with Epigallocatechin 3-gallate (EGCG)

The application of Epigallocatechin-3-gallate (EGCG) in food industry was limited by its low stability in aqueous solutions and poor bioavailability in vivo. The novel EGCG glycosylated arachin nanoparticles (Ara-CMCS-EGCG) and EGCG glycosylated casein nanoparticles (Cas-CMCS-EGCG) were prepared to improve the stability and bioavailability of EGCG. The effect of different variables on the storage stability and the slow-release behavior of novel glycosylation complexes in nanoparticle background solution and artificial gastrointestinal fluid were investigated. The results showed that the DPPH scavenging activity of Ara-CMCS-EGCG and Cas-CMCS-EGCG were stable in temperature (25 ∼ 70 °C). EGCG could enhance the crosslinking effect of molecular particles in glycosylation complexes solution. The glycosylated protein nanoparticles were stable to acid-base and enzymolysis in simulated gastrointestinal fluid. The release rate of EGCG in simulated intestinal fluid was higher than that in simulated gastric fluid. The glycosylated protein carrier can not only release EGCG slowly, but also significantly improve the stability and bioavailability of EGCG in simulated gastrointestinal fluid.

Incorporation of cinnamon essential oil-loaded Pickering emulsion for improving antimicrobial properties and control release of chitosan/gelatin films

In this research, cinnamon essential oil (CEO) loaded Pickering emulsion was incorporated into chitosan (CS)/gelatin (GEL) complex films. These antimicrobial functionalizations of biobased packaging films containing different contents (5, 7.5, and 10 mL) of CEO-loaded Pickering emulsion were evaluated on the microstructure, physicochemical, mechanical, barrier and antimicrobial properties. CEO-loaded Pickering emulsion was herein prepared with zein nanoparticles as a stabilizer showed an average size of 113.37 nm and exhibited excellent physical stability. Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray scattering (WAXS) analyses revealed that the CEO-loaded Pickering emulsion showed compatibility with CS/GEL matrix. Not only mechanical properties but also barrier properties of the prepared films were significantly improved (P < 0.05) by incorporating CEO-loaded Pickering emulsion. Furthermore, incorporating CEO-loaded Pickering emulsion with CS/GEL led to the formation of high antimicrobial against Pseudomonad paralactis MN10 and Lactobacillus sakei VMR17 with slow-release behavior of CEO. These results suggested that Pickering emulsion is a promising antimicrobial agent delivery system for biopolymer based active packaging, notably for the conception of novel active packaging biobased polymers.

Risk assessment of Artemia egg shell-Mg-P composites as a slow-release phosphorus fertilizer during its formation and application in typical heavy metals contaminated environment

Artemia egg shell loaded with nano-magnesium (shell-Mg) can be used to recover phosphorus from wastewater. The exhausted Artemia egg shell-Mg (denoted as shell-Mg-P) can be used as a slow-release fertilizer for phosphorus reuse. However, due to the coexistence of heavy metal ions in the environment, the application of slow-release fertilizer for phosphorus removal and reuse may have potential risks. In this paper, the potential risks of Pb2+, Cd2+, Zn2+ and Cu2+ in phosphorus wastewater and soil were studied from the formation and application process of shell-Mg-P. The result showed that shell-Mg adsorbed Pb2+, Cd2+, Zn2+ and Cu2+ in phosphate wastewater during the formation of shell-Mg-P and became shell-Mg-P-metal hybrid biomaterial. Although the experiment proved that the existence of heavy metal ions did not affect the phosphorus slow-release behavior of slow-release fertilizer, but the heavy metal ions in the shell-Mg-P-metal were also slow released. The pot experiment results confirmed that the slow-release phosphorus fertilizers (shell-Mg-P and shell-Mg-P-metal) in the soil polluted in low concentration of heavy metals can reduce the amount of heavy metals in whole wheat seedlings and promote wheat seedling growth. However, the application of slow-release fertilizers increased the translocation efficiency (TFR to SL) of metal from root (R) to aboveground part (stem and leaves, SL), promoted the transportation of heavy metals from roots to the stems and leaves, and increased the safety risk of the wheat seedling edible. Therefore, besides the positive role of slow-release fertilizers in retaining heavy metals and reducing the amount of heavy metals in whole seedlings, the risk that it may aggravate the translocation of heavy metals to stems and leaves should be paid more attention, so as to ensure the safe and reliable application of slow-release fertilizers.

Effect of addition of biopolymer coated DAP on phosphorus release kinetics over an incubation time

Phosphorus (P) use efficiency is very low (5 to 25%) due to fixation with Ca+2/Mg+2 in alkaline/calcareous soils and Fe2+/Al3+ in acid soils, reduces the availability of phosphorus in soil. Among the various approaches used to enhance PUE, polymer coated fertilizers are relatively a new concept. Therefore, to alleviate the effects of low use efficiency of inorganic fertilizers and its losses in soil, the incubation study was conducted during 2020 at Tamil Nadu Agricultural University to check the slow-release behaviour of coated DAP fertilizer using biopolymers like chitosan and sodium alginate. The incubation experiment was made with six different coatings of biopolymers and uncoated DAP for studying the release behaviour of P from coated fertilizers. Randomized block design was followed with seven treatments in triplicate and sampling was taken at the intervals of 2nd hour, 4th hour, 120th hour, 7, 14, 28, 35, 42 and 49 days of incubation. A study on slow-release property of coated fertilizers indicated that the treatment combination of both chitosan and sodium alginate (C5A5 - CSACDAP) coated DAP performed well by releasing the P from coated fertilizer was achieved till 35th day of incubation followed by the combination of both chitosan and sodium alginate (C4A4 - CSACDAP). This study indicated that the combination of both the polymers forms a strong polyion complex and tends to give the P release for a longer period than the individual coatings of both polymers on the DAP granule.

Weed control and slow-release behavior of 2-methyl-4-chlorophenoxyacetate intercalated layered double hydroxide

The efficient utilization of pesticides is an essential factor affecting crop yield. Thus, the controllable slow-release of pesticides using nanomaterials has attracted considerable attention. In this work, pesticides 2-methyl-4-chlorophenoxyacetate (MCPA) intercalated layered double hydroxides (MCPA/LDH) were successfully prepared using the coprecipitation method and characterized via FTIR, XRD, and SEM. The release behavior of MCPA/LDH was studied and analyzed under different anion, pH, and organic matter conditions. For practical applications, four types of soil from different regions were selected, and the release effect of MCPA/LDH was tested 60 days. The release behavior was fitted to the Higuchi kinetic model, in which the release mechanism was determined to be the ion exchange effect. In a pot experiment, the weed control effect of MCPA/LDH exhibited improved and long-term results than that of the control groups. Hence, this study provides an effective strategy for the efficient utilization of MCPA demonstrating its potential applications in agricultural production.

Controlled release of corrosion inhibitor from microwave-responsive capsules and anti-corrosion performance of steel bars

A novel type of microwave-responsive, actively controlling capsule (ActiveCaps) is designed and prepared. In this study, ActiveCaps are used to carry corrosion inhibitors, and their controlled release behaviour is studied using ethylenediamine tetra-acetic acid (EDTA) titration in a simulated concrete pore solution. Electrochemical measurements were then performed to investigate the influence of controlled release on the anti-corrosion performance of the steel bars. The results show that ActiveCaps have a slow and sustained release behaviour, following the Peppas–Sahlin release model. Compared with the traditional direct addition method, the controlled release of the inhibitor Na2PO3F through ActiveCaps can form a thicker passive film on steel bars, and the inhibition efficiency is increased by 28.73% at 28 d, indicating a higher anti-corrosion performance in the long term. This is due to the formation of Ca5(PO4)3F, which serves as a protective layer covering the surface of the steel bars, precipitated by the reaction between the sustained-released Na2PO3F and Ca2+ in solution. Thus, the utilisation efficiency of Na2PO3F is improved. The proposed novel, actively controlling technology provides a promising alternative for enhancing the durability of reinforced concrete structures using corrosion inhibitors effectively.

Engineered 3D-Printed Polyvinyl Alcohol Scaffolds Incorporating β-Tricalcium Phosphate and Icariin Induce Bone Regeneration in Rat Skull Defect Model.

The skull defects are challenging to self-heal, and autologous bone graft repair has numerous drawbacks. The scaffolds for the rapid and effective repair of skull defects have become an important research topic. In this study, polyvinyl alcohol (PVA)/β-tricalcium phosphate(β-TCP) composite scaffolds containing icariin (ICA) were prepared through direct-ink three-dimensional (3D) printing technology. β-TCP in the composite scaffold had osteoconductive capability, and the ICA molecule had osteoinductive capacity. The β-TCP and ICA components in the composite scaffold can enhance the capability to repair skull defects. We show that ICA exhibited a slow-release behaviour within 80 days. This behaviour helped the scaffold to continuously stimulate the formation of new bone. The results of in vitro cell compatibility experiments showed that the addition of ICA molecules contributed to the adhesion and proliferation of MC-3T3-E1 cells. The level of alkaline phosphatase secretion demonstrated that the slow release of ICA can promote the osteogenic differentiation of MC-3T3-E1 cells. The introduction of ICA molecules accelerated the in situ bone regeneration in in vivo. It is concluded that the 3D-printed PVA scaffold with β-TCP and ICA has a wide range of potential applications in the field of skull defect treatment.

Optimization of Maduramicin Ammonium-Loaded Nanostructured Lipid Carriers Using Box-Behnken Design for Enhanced Anticoccidial Effect against Eimeria tenella in Broiler Chickens.

Maduramicin ammonium (MAD) is one of the most frequently used anticoccidial agents in broiler chickens. However, the high toxicity and low solubility of MAD limit its clinical application. In this study, MAD-loaded nanostructured lipid carriers (MAD–NLCs) were prepared to overcome the defects of MAD by using highly soluble nanostructured lipid carriers (NLCs). The formulation was optimized via a three-level, three-factor Box–Behnken response surface method. Then, the optimal MAD–NLCs were evaluated according to their hydrodynamic diameter (HD), zeta potential (ZP), crystal structure, encapsulation efficiency (EE), drug loading (DL), in vitro release, and anticoccidial effect. The optimal MAD–NLCs had an HD of 153.6 ± 3.044 nm and a ZP of −41.4 ± 1.10 mV. The X-ray diffraction and Fourier-transform infrared spectroscopy results indicated that the MAD was encapsulated in the NLCs in an amorphous state. The EE and DL were 90.49 ± 1.05% and 2.34 ± 0.04%, respectively, which indicated that the MAD was efficiently encapsulated in the NLCs. In the in vitro study, the MAD–NLCs demonstrated a slow and sustained drug release behavior. Notably, MAD–NLCs had an excellent anticoccidial effect against Eimeria tenella in broiler chickens. In summary, MAD–NLCs have huge potential to form a new preparation administered via drinking water with a powerful anticoccidial effect.

Nitrogen slow-release behavior of oxamide granules in two different types of paddy soils

Oxamide is a potential slow-release nitrogen (N) fertilizer, especially under waterlogged conditions, due to its low solubility in water and the slow-release of ammonium by soil amidases. To investigate the effects of oxamide granules (2.00-2.38 mm in diameter) as a single basal fertilizer (180 or 144 kg N ha−1) on rice growth, soil properties, and N use efficiency in terms of N recovery efficiency (NRE), we conducted field experiments on two different types of paddy soils over two rice-growing seasons. Results showed that the fertilization effects of oxamide granules varied between the two types of paddy soils. In the red clayey paddy soil, the grain yields for both rice-growing seasons were high with a significantly higher NRE in the oxamide treatment than in the urea treatment. However, in the alluvial sandy paddy soil, the grain yields in the oxamide treatment were slightly lower than those in the urea treatment. Furthermore, oxamide produced little improvement in NRE in the alluvial sandy paddy soil. Soil incubation experiments over 98 d were also carried out to evaluate the factors affecting the N release behavior of oxamide granules in the two types of paddy soils. We found that the amidase activity was higher and, therefore, the oxamide hydrolysis rate was faster in the alluvial sandy paddy soil, which had a higher soil pH value and organic matter content, compared to the red clayey paddy soil. The faster N release and the longer growth period resulted in a mismatch between N supply by oxamide and rice demand, which, in turn, led to little improvement in NRE and a decreased grain yield in the alluvial sandy paddy soil, especially in the reduced oxamide treatment. These results could help select the appropriate size of oxamide granules for use as a slow-release N fertilizer depending on the soil properties and growth period of rice.

The slow release behavior of soy protein isolate/κ-carrageenan composite hydrogel: Effect of konjac glucomannan

Composite hydrogels are known for their potential applications in drug delivery fields. Pure κ-carrageenan (KC) hydrogels have a drug burst release behavior, which greatly limit their applications. In this study, konjac glucomannan (KGM) was used to further improve the properties of soy protein isolate (SPI)/KC composite hydrogels. The results showed that the viscoelasticity of the composite hydrogels increased at KC/KGM ratio 9:1 due to the increase of hydrogen bond interaction. Excessive addition of KGM in composite hydrogels led to the increase in frequency dependence and gel network cavity as well as the decrease in gel cohesiveness. In vitro study on glucose release behavior of composite hydrogels showed that the glucose slow release behavior was enhanced by a small amount of KGM incorporation and had highly positive correlation with the gel viscoelasticity. These results suggested that KGM had the potential to enhance the properties and drug release characteristics of composite hydrogels.

Synthesis and Performance Evaluation of Cellulose-based Slow-release Fertilizer: A Review

Cellulose-based materials are attractive candidates for the fabrication of sustainable and eco-friendly slow-release fertilizers. The ability of the cellulose structure to be modified and functionalized makes it promising as a scaffold backbone in the development of advanced agricultural materials. In this review, different synthesis techniques of cellulose-based slow-release fertilizers are discussed. Crucial parameters in the design of the slow-release fertilizers (i.e., slow-release behavior, water retention properties, and biodegradability) are presented. The applications of cellulose-based fertilizers in enhancing the growth of agricultural and horticultural commodities are provided. To date, solution polymerization is more widely employed in the preparation of cellulose-based slow-release fertilizers due to its low cost and simple operation, with no solvent recovery required. Esterification tends to be the most typical reaction during the synthesis of the fertilizers because of its high substrate solubility and more straightforward product purification. This review can be used as a reference to develop other efficient cellulose-based slow-release fertilizers that can be utilized to delay the release of fertilizers and prevent the overuse of fertilizers.

MOF Hybrid for Long-Term Pest Management and Micronutrient Supply Triggered with Protease.

Advanced intelligent systems for delivery of pesticides or fertilizers require formulations that allow for long-term efficacy. In this work, a metal-organic framework (MOF) hybrid was developed for long-term pest management and micronutrient supply. Zeolitic imidazolate framework-8 was fabricated for crop micronutrients (Zn2+) supply and insecticide dinotefuran (DNF) encapsulation. Polymethylmethacrylate was polymerized in situ to impart the MOF hybrid with sustained cargo delivery. Then, zein was introduced to facilitate protease-triggered cargo release associated with the microenvironment of pests and targeted release. The resulting MOF hybrid exhibited stimulus-responsive, slow-release behaviors. Sustained DNF delivery was achieved over a period of at least 32 days in soil. Compared with that of free DNF, the UV resistance of DNF in the MOF hybrid increased by nearly 10 times, and the insecticidal efficiency increased 33.3% with leaching treatment and 40.1% after incubating in a greenhouse for 14 days. This MOF hybrid provides a controlled, targeted, and sustained delivery formulation for long-term pest management and crop micronutrient supply and has huge application prospects in sustainable agriculture.

Nutrients enriched biochar production through Co-Pyrolysis of poultry litter with banana peduncle and phosphogypsum waste

Poultry litter (PL) utilisation has been widely studied for production of phosphorus (P) rich biochars. Recent research documented co-pyrolysis of PL with nutrient rich chemical additives like rock phosphate, phosphoric acid and magnesium (Mg) salts for production of P–Mg enriched biochar with improved P use efficiency. However, research is highly scarce on utilisation of waste materials for production of PL biochar enriched in P, potassium (K) and sulphur (S). In this context, present work investigated co-pyrolysis (700°C, 10°C/min, 1h residence time) of PL with banana peduncle (BP) and phosphogypsum (PG) in different w/w ratios (1:1:1, 1:2:1, 1:3:1) of BP-PL-PG for production of K–P–S enriched biochars composites. These biochars mainly showed variations in their K–P–S contents. The K (5.1%) and S (11.35%) enrichment was relatively higher in BP-PL-PG (1:1:1) biochar than PL biochar (K-3.70% and S-0.96%). However, P content was higher in PL biochar (4.48%) and was reduced in biochar composites. The P contents were 3.84, 2.84, and 2.44% in BP-PL-PG (1:3:1), BP-PL-PG (1:2:1) and BP-PL-PG (1:1:1) composites respectively. In biochars, P was present predominantly as Ca–Mg bound form. Furthermore, best fit of second order kinetic model indicated slow-release behaviour of P from biochars and composites. These results highlight the scope of co-pyrolysis of PL with selected wastes for production of multi-nutrients enriched biochars with improved nutrient availability for soil application.

Regulation Effects of Beeswax in the Intermediate Oil Phase on the Stability, Oral Sensation and Flavor Release Properties of Pickering Double Emulsions.

Double emulsions (W/O/W) with compartmentalized structures have attracted a lot of research interests due to their diverse applications in the food industry. Herein, oil phase of double emulsions was gelled with beeswax (BW), and the effects of BW mass ratios (0–8.0%) on the stability, oral sensation, and flavor release profile of the emulsions were investigated. Rheological tests revealed that the mechanical properties of double emulsions were dependent on the mass ratio of BW. With the increase in BW content, double emulsions showed a higher resistance against deformation, and lower friction coefficient with a smoother mouthfeel. Turbiscan analysis showed that the addition of BW improved the stability of double emulsions during a 14 days’ storage, under freeze–thawed, and osmotic pressure conditions, but it did not improve the heating stability of double emulsions. The addition of BW contributed to lower air-emulsion partition coefficients of flavor (2,3-diacetyl) compared to those without the addition of BW at 20 °C and 37 °C, respectively. Furthermore, the addition of BW and its mass ratio significantly altered the flavor release behavior during the open-bottle storage of double emulsions. The response value of 0% BW dropped sharply on the first day of opening storage, showing a burst release behavior. While a slow and sustained release behavior was observed in double emulsions with 8.0% BW. In conclusion, gelation of the intermediate oil phase of double emulsions significantly enhanced the stability of double emulsions with tunable oral sensation and flavor release by varying the mass ratio of beeswax.

Nanopesticide Formulation from Pyraclostrobin and Graphene Oxide as a Nanocarrier and Application in Controlling Plant Fungal Pathogens.

Efficient and environment-friendly nanopesticide delivery systems are critical for the sustainable development of agriculture. In this study, a graphene oxide nanocomposite was developed for pesticide delivery and plant protection with pyraclostrobin as the model pesticide. First, graphene oxide–pyraclostrobin nanocomposite was prepared through fast adsorption of pyraclostrobin onto graphene oxide with a maximum loading of 87.04%. The as-prepared graphene oxide–pyraclostrobin nanocomposite exhibited high stability during two years of storage, suggesting its high potential in practical application. The graphene oxide–pyraclostrobin nanocomposite could achieve temperature (25 °C, 30 °C and 35 °C) and pH (5, 7 and 9) slow-release behavior, which overcomes the burst release of conventional pyraclostrobin formulation. Furthermore, graphene oxide–pyraclostrobin nanocomposite exhibited considerable antifungal activities against Fusarium graminearum and Sclerotinia sclerotiorum both in vitro and in vivo. The cotoxicity factor assay revealed that there was a synergistic interaction when graphene oxide and pyraclostrobin were combined at the ratio of 1:1 against the mycelial growth of Fusarium graminearum and Sclerotinia sclerotiorum with co-toxicity coefficient values exceeding 100 in vitro. The control efficacy of graphene oxide–pyraclostrobin nanocomposite was 71.35% and 62.32% against Fusarium graminearum and Sclerotinia sclerotiorum in greenhouse, respectively, which was higher than that of single graphene oxide and pyraclostrobin. In general, the present study provides a candidate nanoformulation for pathogenic fungal control in plants, and may also expand the application of graphene oxide materials in controlling plant fungal pathogens and sustainable agriculture.

Tunable paclitaxel release carrier using diselenide-disulfide balance as regulator

There are many reasons that lead to the failure of cancer chemotherapy, such as uncontrolled drug release, low drug utilization, and severe side effects. To overcome these obstacles, two kinds of thermal and redox-responsive copolymers with multiple diselenide/disulfide linkages, polyethylene glycol -alt- diselenodipropionate/disulfhydryldipropionate-b-poly(N-isopropylacrylamide) (abbreviated as PEG-alt-DSeDP-b-PNIPAM and PEG-alt-DSDP-b-PNIPAM) were fabricated by alternative esterification and following atom transfer radical polymerization. Afterward, these prepared copolymers were mixed in line with the mass ratio of 8:0, 5:3, 3:5, 0:8 (denoted as S1, S2, S3, and S4, respectively), and self-assembled with paclitaxel (PTX) to obtain PTX-loaded S1, S2, S3, and S4 nanomicellar assemblies, aiming to realize PTX tunable release using diselenide-disulfide balance as regulator. The chemical structures of these two copolymers were characterized by gel permeation chromatography, indicating eight diselenide/disulfide linkages and eight PEG units were contained in these copolymers. Moreover, the thermal-responsive property was detected by UV–vis spectroscopy, meanwhile, the redox responsiveness was observed by TEM in the presence of 10 mM glutathione. We found that 76.90% of PTX was released from S1 nanomicelles within 23 h. In contrast, this percentage decreased to 64.53% for S4 nanomicelles even the incubation time prolonged, indicating explosive and slow release behaviors of S1 and S4 nanomicelles, respectively. In addition, gradually decreased fluorescence intensity around the cellular nucleus was occurred from S1 to S4 orderly, which was consistent with cellular uptake and in vivo anti-tumor experiments. Taken together, this work not only provides a strategy for tunable PTX release, but also improves effectiveness of PTX in cancer treatment.

Poly(lactic acid-co-glycolic acid)-based celecoxib extended-release microspheres for the local treatment of traumatic heterotopic ossification.

Traumatic heterotopic ossification (THO) is a serious and common clinical post-traumatic complication for which there is no effective and safe drug treatment. Routine administration of nonsteroidal anti-inflammatory drugs (NSAIDs) after injury is extensively used approach for THO. However, serious adverse events can occur in the event of an overdose of NSAIDs. In our study, we have developed a poly(lactic acid-co-glycolic acid) (PLGA) microsphere by emulsifying solvent volatilization for the prolonged slow delivery of celecoxib (CLX). Three groups of celecoxib-poly(lactic acid-co-glycolic acid) microspheres (CLX-PLGA MPs) were prepared with particle sizes of 3.75±1.28μm, 49.56±17.15μm, and 94.98±42.53μm. Meanwhile, related parameters of microspheres in each group were studied: drug loading (DL), encapsulation rate (EE), and slow-release behavior. The DL and EE of the 3 CLX-PLGA MPs did not vary significantly, and subsequently, we selected the second drug loading microspheres with a retardation period of about 70 days for subsequent experiments. Moreover, cellular and animal experiments suggest that the microspheres are biocompatible and can be safely applied to localized trauma tissue. Finally, it is demonstrated that CLX-PLGA MPs have an effect on inhibiting the osteogenic differentiation of bone marrow mesenchymal stem cells and have the potential to inhibit ectopic bone formation of the THO model in Sprague-Dawley rat. Therefore, this study suggests that CLX-PLGA MPs are expected to be applied topically in the early post-traumatic period to prevent the development of THO.

Assessment of Antifungal Efficacy and Release Behavior of Fungicide-Loaded Chitosan-Carrageenan Nanoparticles against Phytopathogenic Fungi.

Biopolymeric Chitosan-Carrageenan nanocomposites 66.6–231.82 nm in size containing the chemical fungicide mancozeb (nano CSCRG-M) were synthesized following a green chemistry approach. The physicochemical study of nanoparticles (NPs) was accomplished using a particle size analyzer, SEM and FTIR. TEM exhibited clover leaf-shaped nanoparticles (248.23 nm) with mancozeb on the inside and entrapped outside. Differential scanning calorimetry and TGA thermogravimetry exhibited the thermal behaviour of the nanoform. Nano CSCRG-1.5 at 1.5 ppm exhibited 83.1% inhibition against Alternaria solani in an in vitro study and performed as well as mancozeb (84.6%). Complete inhibition was exhibited in Sclerotinia sclerotiorum at 1.0 and 1.5 ppm with the nanoformulation. The in vivo disease control efficacy of mancozeb-loaded nanoparticles against A. solani in pathogenized plants was found to be relatively higher (79.4 ± 1.7) than that of commercial fungicide (76 ± 1.1%) in pot conditions. Nanomancozeb showed superior efficacy for plant growth parameters, such as germination percentage, root–shoot ratio and dry biomass. The nanoformulation showed higher cell viability compared to mancozeb in Vero cell cultures at 0.25 and 0.50 mg/mL in the resazurin assay. CSCRG-0.5 showed slow-release behavior up to 10 h. Thus, these green nano-based approaches may help combat soil and water pollution caused by harmful chemical pesticides.