Controlled Release Performance Research Articles

Enhancing compatibility of polylactic acid and lignin through acetylation for improving controlled release of pesticide.

Improving the compatibility between polylactic acid (PLA) and lignin is crucial for developing innovative PLA-based controlled release systems for pesticides. This study addresses the challenge of enhancing the compatibility of alkali lignin (AL) with PLA by acetylated lignin (ACL). The main aim is to synthesize and evaluate pesticide-loaded microspheres for controlled release performance using fluazinam (FZ) as the model pesticide. We synthesized three distinct pesticide-loaded microspheres (FZ@PLA, FZ@AL-PLA, and FZ@ACL-PLA). The results demonstrated a significant enhancement in the spherical morphology of FZ@ACL-PLA compared to FZ@AL-PLA, attributed to the introduction of acetyl groups that transformed the surface from irregularities to a smooth, rounded, and microporous architecture. This structural modification notably boosted the pesticide loading capacity to 42.44 wt% and entrapment efficiency to 89.20%. Controlled release studies exhibited prolonged release beyond 30 days without equilibrium attainment for FZ@ACL-PLA. This was facilitated by hydrogen bonding between ACL-PLA and FZ, coupled with a spatial site-blocking effect, effectively restraining abrupt pesticide release. Kinetic analysis revealed Fickian diffusion as the primary release mechanism at moderate temperatures and anomalous transport at elevated temperatures. Additionally, FZ@ACL-PLA demonstrated commendable storage stability and photostability. The study underscores the efficacy of ACL-modified PLA microspheres in efficiently entrapping FZ and enabling controlled release. The findings offer crucial insights for developing PLA-based pesticide-controlled release systems, highlighting the significance of ACL in enhancing pesticide loading, entrapment efficiency, and controlled release performance. © 2025 Society of Chemical Industry.

Photoluminescent oxaliplatin loaded porous starch coated with pectin biopolymer: Design, fabrication, and controlled drug delivery

Today’s carbohydrate-based bio-carriers have attracted more attention as drug delivery agents, so they have brilliant biocompatibility, as well as, controlled drug release potential. Considering these, the porous starch (PS) with the honeycomb network was in situ synthesized in the presence of pre-synthesized carbon dots (CDs/PS). The SEM displayed the porous structure of CDs/PS with a uniform dispersion of CDs in the polymer matrix. BET analysis obtained the diameter of the porous sites at about 37.319 nm. After oxaliplatin (OXP) loading the OXP/CDs/PS was coated with the pectin (Pec) in a green strategy ((OXP/CDs/PS)@Pec). The drug release studies displayed that the (OXP/CDs/PS)@Pec has a controlled release performance than OXP/CDs/PS in the simulated pH of oral drug delivery condition. The biocompatibility of the (CDs/PS)@Pec and its cancer cell-killing capability after drug loading were approved via MTT test. These results promoted us that the modification of OXP/CDs/PS with Pec achieves a controlled drug release profile and the fabricated system could be suggested as a new delivery system with targeted delivery potential.

Engineering high-performance and multifunctional seed coating agents from lignocellulosic components

The use of natural polymers, such as biomass, as an alternative to non-renewable polymer attracts a growing interest in sustainable agricultural production. Seed coating, an important treatment for enhancing crop performance, could be an environmentally-friendly and promising option when utilizing materials based on natural polymers. Herein, biomass-based seed coating agents derived from cellulose and lignin through a simple process were developed. Carboxymethyl cellulose was used as the primary substrate for membrane formation, supplemented with sodium lignosulfonate as an additive to enhance its mechanic and anti-UV properties. The prepared seed coating agents showed promising film-forming property, flexibility, and water retention capacity. Furthermore, these agents were effective in controlled release and anti-UV performances for pesticides encapsulated in it. Additionally, the thickness of the seed coat could be finely tuned by controlling the soaking time, and therefore resulting in an adjustable germination time. More importantly, the agents demonstrated natural degradability with nearly 80 % degradation at 60 days. It is concluded that the seed coating agents prepared provides new insight into the use of biomass-based materials in sustainable agricultural systems.

PH-sensitive and redox-responsive poly(tetraethylene glycol) nanoparticle-based platform for cancer treatment

Effective drug delivery with precise tumour targeting is crucial for cancer treatment. To address the challenges posed by the specificity and complexity of the tumour microenvironment, we developed a poly(tetraethylene glycol)-based disulfide nanoparticle (NP) platform and explored its potential in cancer treatment, focusing on drug loading and controlled release performance. Poly(tetraethylene glycol) NPs were characterised using nuclear magnetic resonance spectroscopy, mass spectrometry, and ultraviolet-visible spectroscopy. Additionally, we evaluated physicochemical properties, including dynamic light scattering, zeta potential analysis, drug loading capacity (DLC), and drug loading efficiency (DLE). The impact of NPs on the mouse colorectal cancer cell line (CT26) and NIH3T3 cells was assessed using a cytotoxicity assay, live/dead staining assay, flow cytometry, and confocal fluorescence microscopy. The experimental results align with the expected chemical structure and physicochemical properties of poly(tetraethylene glycol) NPs. These NPs exhibit high DLE (78.7%) and DLC (12%), with minimal changes in particle size over time in different media.In vitroexperiments revealed that the NPs can induce significant cytotoxicity and apoptosis in CT26 cells. Cellular uptake notably increases with increasing concentration and exposure time. The confocal microscopic analysis confirmed the effective distribution and accumulation of NPs within cells. In conclusion, poly(tetraethylene glycol) NPs hold promise for improving drug-delivery efficiency, offering potential advancements in cancer treatment.

Preparation, characterization and heat release behavior of inclusion complexes formed between carvone or limonene and acyclic cucurbit[n]urils.

Carvone and limonene are naturally occurring monoterpenoids with unique aromas, making them valuable substances in synthetic fragrance production. However, their application is limited due to low stability and rapid volatilization. To address this challenge, host-guest complexes offer a promising solution. In this study, two acyclic cucurbit[n]urils were synthesized to form inclusion complexes with carvone and limonene, aiming to enhance their thermal stability and achieve excellent heat release properties. The binding behavior of the complexes was investigated using NMR, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and molecular bonding analyses, confirming the formation of host-guest inclusion complexes. Our study successfully prepared four inclusion complexes (M1/CA, M2/CA, M1/LI, M2/LI) and characterized them using NMR, XRD and FTIR techniques. These complexes exhibited a 1:1 stoichiometric ratio, and their binding constants were determined through fluorescence titration. The thermal controlled release experiment shows that the degree of carvone and limonene release is different with a change of temperature, indicating that the inclusion complexes have good thermally controlled release performance, and the thermal release retention rate has a certain correlation with KS value. The larger the KS value, the higher the thermal release retention rate of the inclusion complexes, the lower the volatilization of the inclusion complexes, the longer the retention time and the better the thermal stability. This study presents a novel approach for developing carvone- and limonene-based fragrances, expanding their application potential in various industries. © 2024 Society of Chemical Industry.

Construction of a MoS2@mSiO2 nanocarrier as a near-infrared/pH dual-responsive platform to control the drug release for anti-tumor

Designing new-type nanosystems to realize the combination of multiple treatment is an efficient routine to enhance the anti-tumor efficacy in clinic. In this study, molybdenum disulfide (MoS2) was selected as a photothermal agent, and mesoporous silica (mSiO2) was coated on the surface of MoS2 using the solvothermal and template removal methods. The chemotherapeutic drug doxorubicin hydrochloride (DOX) as a model drug was then loaded into the above MoS2@mSiO2 nanocarrier to prepare the tumor-targeting MoS2@mSiO2-DOX nanosystem. XRD, UV–Vis, FTIR, SEM, TEM, and DLS results jointly confirmed that the MoS2@mSiO2-DOX nanosystem with a particle size of approximately 370 nm was successfully synthesized. The XPS and BET analysis identified that the outer layer of MoS2@mSiO2 nanocarrier was SiO2, which has a large surface area of 99.41 m2/g with an average pore size of 3.5 nm coated on the MoS2. The in-vitro cytotoxicity and photothermal performance of the MoS2@mSiO2 nanodrug delivery system was tested, and the results show that MoS2@mSiO2 has a low toxicity to normal human liver cells (HL-7702), and which also exhibits a good photothermal stability with a photothermal conversion efficiency of 28.8%. With the aid of the large specific surface area of mSiO2 and the opposite zeta potential, a high amount of DOX was loaded on MoS2@mSiO2 nanocarrier, and the measured loading efficiency of DOX can reach up to 48.87%. The 48 h-drug release rate of MoS2@mSiO2-DOX reaches 35.65% under the conditions of near infrared (NIR) laser irradiation at pH=5.0, which is nearly 5 times higher than that of 6.26% under the normal physiological environment (pH=7.4 without NIR laser irradiation), indicating that the MoS2@mSiO2-DOX nanosystem possesses obvious pH and NIR laser responsive release characteristics. The MoS2@mSiO2 nanocarrier has good cytocompatibility, outstanding photothermal conversion and drug loading properties, and after DOX adsorption, the system exhibits excellent pH and laser responsive drug controlled release performance, which is expected to be widely used in the field of combining the photothermal-chemotherapy to synergistically resist tumor.

Development of gelatin-methacryloyl composite carriers for bone morphogenetic Protein-2 delivery: A potential strategy for spinal fusion.

To reduce the risk of nonunion after spinal fusion surgery, the in situ transplantation of bone marrow mesenchymal stem cells (BMSCs) induced toward osteogenic differentiation by bone morphogenetic protein-2 (BMP2) has been proven effective. However, the current biological agents used for transplantation have limitations, such as a short half-life and low bioavailability. To address this, our study utilized a safe and effective gelatin-methacryloyl (GelMA) as a carrier for BMP2. In vitro, experiments were conducted to observe the ability of this composite vehicle to induce osteogenic differentiation of BMSCs. The results showed that the GelMA hydrogel, with its critical properties and controlled release performance of BMP2, exhibited a slow release of BMP2 over 30 days. Moreover, the GelMA hydrogel not only enhanced the proliferation activity of BMSCs but also significantly promoted their osteogenic differentiation ability, surpassing the BMP2 effects. To investigate the potential of the GelMA-BMP2 composite vehicle, a rabbit model was employed to explore its ability to induce in situ intervertebral fusion by BMSCs. Transplantation experiments in rabbits demonstrated the effective induction of intervertebral bone fusion by the GelMA-BMP2-BMSC composite vehicle. In conclusion, the GelMA-BMP2-BMSC composite vehicle shows promising prospects in preclinical translational therapy for spinal intervertebral fusion. It addresses the limitations of current biological agents and offers a controlled release of BMP2, enhancing the proliferation and osteogenic differentiation of BMSCs.

Mannitol-coated hydroxypropyl methylcellulose as an alternative directly compressible controlled release excipient

One of the most common forms of controlled release technology for oral drug delivery comprises an active ingredient dispersed in a hydrophilic matrix forming polymer such as hydroxypropyl methylcellulose (HPMC), which is tableted via direct compression. However, HPMC may pose problems in direct compression due to its poor flowability. Hence, mannitol syrup was spray-coated over fluidized HPMC particles to produce co-processed HPMC–mannitol at ratios of 20:80, 50:50, and 70:30. Particles of pure HPMC, co-processed HPMC–mannitol, and their respective physical mixtures were evaluated for powder flowability, compression profiles, and controlled release performance. It was found that co-processed HPMC–mannitol consisted of particles with improved flow compared to pure HPMC particles. Sufficiently strong tablets of >2 MPa could be produced at moderate to high compression forces of 150–200 MPa. The dissolution profile could be tuned to obtain desired release profiles by altering HPMC–mannitol ratios. Co-processed HPMC–mannitol offers an interesting addition to the formulator’s toolbox in the design of controlled release formulations for direct compression.

Enhancing Film Cross-Linking through VTES Copolymerization in Polymer Latex for Increasing Controlled-Release Performance of Film-Coated Fertilizer Granules

Enhancing Film Cross-Linking through VTES Copolymerization in Polymer Latex for Increasing Controlled-Release Performance of Film-Coated Fertilizer Granules

Pharmacokinetics study of sweet corn cob polysaccharide nano emulsion microcapsules

Fluorescein isothiocyanate (FITC) was used for the fluorescent labeling of sweet corn cob polysaccharide (SCP), followed by identification using fluorescence spectroscopy, UV–Visible spectroscopy, infrared spectroscopy, and NMR analysis. The results confirmed the successful attachment of FITC to SCP with a substitution degree of 1.28%. This established fluorescent sweet corn cob polysaccharide (FSCP) was then subjected to an in vivo quantitative analysis, in which mice were administered with FSCP, fluorescent sweet corn cob polysaccharide nanoemulsion (FSCP-NE), and fluorescent sweet corn cob polysaccharide nano emulsion microcapsule (FSCP-NE-ME) via gavage followed by investigating the in vivo plasma pharmacokinetics and tissue distribution. The results revealed that FSCP-NE could improve the utilization efficiency of SCP, and the FSCP-NE microcapsules exhibited good controlled-release performance, which significantly improved the utilization efficiency of SCP. The absorption and metabolism of SCP in vivo were explored next, which provided the reference for future research and development on SCP for application in the fields of nutraceuticals and pharmaceuticals.

Multifunctional and antimicrobial carboxymethyl cellulose-based active hydrogel film for fruits packaging and preservation

Hydrogel-based film materials have been extensively used in the field of food packaging, whereas the water loss issue and relatively simple function of hydrogel films severely limited their practical application. Herein, we successfully prepared a sort of multi-functional sodium carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA)/tannic acid (TA)/ginkgo biloba leaf extract (EGBL) hydrogel film (CPTE) and designed as active food preservation system. The water content of the resultant hydrogel film remains >97% when placed in air for one month after solvent displacement. Furthermore, the CPT0.1E1 hydrogel film possesses satisfied UV blocking, antioxidation (82.11%), oxygen barrier (7.91 cm3/(m2·24 h 0.1 MPa)) and controlled release performances. When applied as packaging film, the CPT0.1E1 hydrogel film could effectively prolong the shelf life of strawberry for 7 days. This work is expected to bring a novel strategy for establishing the next generation of hydrogel films-based fruits packaging and preservation with satisfied anti-dehydrating and multi-functional properties.

Synergistic preparation and application in PCU of α-calcium sulfate hemihydrate whiskers from phosphogypsum and electrolytic manganese residue

The α-calcium sulfate hemihydrate whiskers (α-CSHWs) were first prepared using phosphogypsum (PG) and electrolytic manganese residue (EMR) as raw materials for coating urea, demonstrating excellent controlled-release properties. The effects of different reaction conditions on α-CSHWs, achieved by optimizing the reaction time, the concentrations of NH4+, Mn2+, and other factors, were discussed. Results showed that when the EMR content was 25 wt%, the reaction temperature was 100 °C, and the reaction time was 3 h, α-CSHWs with a length-to-diameter ratio of 39 were obtained. Through experiments and density functional theory (DFT), the mechanism of α-CSHWs preparation was elucidated. The results show that the addition of EMR reduces the content of impurity ions PO43− and F− in PG while introducing NH4+ and Mn2+. Interestingly, both NH4+ and Mn2+ can reduce the nucleation time of α-CSHWs, while PO43−, Mn2+, and F− are more likely to adsorb on the (0 0 6) crystal plane of α-CSHWs, NH4+ readily adsorbs on the (4 0 0) crystal plane. The controlled-release performance of modified α-CSHWs incorporated into polyurethane-coated urea (PCU) was investigated, and it was found that the addition of Mα significantly prolonged the nutrient release period, with the period extending up to 116 days for coatings of 5wt% and above. This work not only enhances the efficiency of PG and EMR utilization but also serves as a reference for the straightforward synthesis and application of α-CSHWs.

Photothermal controlled-release microcapsule pesticide delivery systems constructed with sodium lignosulfonate and transition metal ions: construction, efficacy and on-demand pesticide delivery.

Widespread application of controlled-release pesticide delivery systems is a feasible and effective method to improve the utilization efficiency of pesticides. However, owing to the high cost and complicated preparation technologies of controlled-release pesticide delivery systems, their applications in agricultural production have been seriously hindered. This study aimed to construct inexpensive photothermally controlled-release pesticide delivery systems using chitosan (CS) and sodium lignosulfonate (LS) as the wall materials, and a coordination assembly strategy of LS with transition metal ions to encapsulate a model pesticide, avermectin (AVM). The resulting complex or nanoparticle photothermal layers in these systems effectively achieved photothermal conversions, and replaced the use of common photothermal agents. In the prepared pesticide-delivery systems, two systems had remarkable photothermal conversion performance and photothermal stabilities with a photothermal conversion efficiency (η) of 24.03% and 28.82%, respectively, under 808 nm, 2 W near-infrared irradiation. The slow-release and ultraviolet-shielding performance of these two systems were markedly enhanced compared with other formulations. The insecticidal activities of these two systems against Plutella xylostella under irradiation with light-emitting diode (LED)-simulated sunlight were also enhanced by 5.20- and 5.06-fold, respectively, compared with that without irradiation of LED-simulated sunlight. Because of their convenient preparations, inexpensive and renewable raw materials, and excellent photothermally controlled-release performance, these on-demand pesticide delivery systems might have significant potential in improving the utilization efficiency of pesticides in modern agriculture. © 2024 Society of Chemical Industry.

Exploring the Synergy between Nano-Formulated Linezolid and Polymyxin B as a Gram-Negative Effective Antibiotic Delivery System Based on Mesoporous Silica Nanoparticles.

Antimicrobial resistance is a current silent pandemic that needs new types of antimicrobial agents different from the classic antibiotics that are known to lose efficiency over time. Encapsulation of antibiotics inside nano-delivery systems could be a promising, effective strategy that is able to delay the capability of pathogens to develop resistance mechanisms against antimicrobials. These systems can be adapted to deliver already discovered antibiotics to specific infection sites in a more successful way. Herein, mesoporous silica nanomaterials are used for an efficient delivery of a linezolid gram-positive antibiotic that acts synergistically with gram-negative antimicrobial polymyxin B. For this purpose, linezolid is encapsulated in the pores of the mesoporous silica, whose outer surface is coated with a polymyxin B membrane disruptor. The nanomaterial showed a good controlled-release performance in the presence of lipopolysaccharide, found in bacteria cell membranes, and the complete bacteria E. coli DH5α. The performed studies demonstrate that when the novel formulation is near bacteria, polymyxin B interacts with the cell membrane, thereby promoting its permeation. After this step, linezolid can easily penetrate the bacteria and act with efficacy to kill the microorganism. The nano-delivery system presents a highly increased antimicrobial efficacy against gram-negative bacteria, where the use of free linezolid is not effective, with a fractional inhibitory concentration index of 0.0063 for E. coli. Moreover, enhanced toxicity against gram-positive bacteria was confirmed thanks to the combination of both antibiotics in the same nanoparticles. Although this new nanomaterial should be further studied to reach clinical practice, the obtained results pave the way to the development of new nanoformulations which could help in the fight against bacterial infections.

Water resistant, biodegradable and flexible corn starch/carboxymethyl cellulose composite film for slow-release fertilizer coating materials

The inherent limitations of Cornstarch (CS) and Carboxymethyl Cellulose (CMC) membranes, such as brittleness, fragility, and water solubility, limit their use in controlled-release fertilizers. This study reports on the synthesis of crosslinked CMC/CS-20-E composite membranes using the casting technique, with epichlorohydrin (ECH) as the crosslinking agent in an acidic environment to crosslink CS and CMC. The synthesized composite film demonstrates remarkable water resistance, as evidenced by the insignificant alteration in its morphology and structure post 72 h of water immersion. Its flexibility is reflected in its capacity to endure knotting and bending, with an elongation at break reaching 78.1 %. Moreover, the degradation rate surpasses 90 % within a span of seven days. The CMC/CS-20-E-x-urea controlled-release fertilizer was subsequently produced using a layer-by-layer self-assembly technique, where urea particles were incorporated into the crosslinked composite solution. This CMC/CS-20-E-x-urea controlled-release fertilizer displayed superior controlled-release performance over a duration of seven days when juxtaposed with pure urea. In particular, the CMC/CS-20-E-3 %-urea controlled-release fertilizer showed a cumulative release rate of 84 % by the seventh day. The controlled-release fertilizers developed in this study offer a promising strategy for creating eco-friendly options that are crucial for fertilizing crops with short growth cycles.

Eco-friendly nano-enabled fertilizers derived from date industry waste for sustainable and controlled-release of P, K and Mg nutrients: sorption mechanisms, controlled-release performance and kinetics

Development of nano-enabled fertilizers from green waste is one of the effective options to enhance global agricultural productions and minimize environmental pollution. In this study, novel, eco-friendly and cost-effective nano- enabled fertilizers (NEF) were synthesized using the planetary ball milling procedure. The NEF (nDPF1and nDPF2) were prepared by impregnation of nanostructured date palm pits (nDPP) with (KH2PO4 + MgO) at 1:1 and 3:1 (w/w) ratios respectively. The nDPP, nDPF1 and nDPF2 were extensively characterized. The produced nano-fertilizers enhanced soil water retention capacity with nDPF2 being the most effective. The water retention capacity of nDPF2 treated soil was 5.6 times higher than that of soil treated with conventional fertilizers. In addition, the nDPF2 exhibited superior sustained lower release rates of P, K and Mg nutrients for longer release periods in comparison with the conventional fertilizers. For instance, P cumulative release percentages from conventional fertilizers, nDPF1 and nDPF2 in soil reached 22.41%, 10.82 and 8.9% respectively within 384 h. Findings from FTIR and XPS analyses suggested that hydrogen bonding and ligand exchange were the main interaction mechanisms of PO4-K-Mg ions with nDPP surface. The released kinetics data of the NEF revealed that power function was the best suitable model to describe the kinetics of P, K and Mg release data from NEF in water and soil. Pot study ascertained that the nano-enabled fertilizers (nDPF1 and nDPF2) significantly promoted biomass production and nutrient uptake of maize plants as compared to commercial fertilizer treated plants. The present work demonstrated the potential of NEF to increase nutrients uptake efficiency, mitigate moisture retention problem in arid soils and reduce nutrients loss through leaching and safeguard the environment.Graphical

Preparation of a novel alginate hydrogel microspheres covered by hollow silica for controlled-release application

Sodium alginate hydrogel has been widely used in the field of controlled-release. In this paper, in order to prevent the negative effect of fast degradation and explosive release of pure sodium alginate hydrogel in the drug delivery process, we developed a novel alginate hydrogel supported by hollow silica microsphere for drug delivery. Briefly, the drugs were fused with sodium alginate and the hollow silica microspheres followed by ion crosslinking to form a composite hydrogel microsphere with a core–shell structure (SA@SiO2). The structure and morphology of the composite hydrogel were characterized by Fourier infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), scanning electron microscope (SEM), transmission electron microscope (TEM) along with fluorescence microscope. On this basis, using three different types of organic compounds (rhodamine B, Indocyanine green and salicylic acid) as model molecules, the controlled-release performance of the SA@SiO2 microspheres were investigated in detail. The research results show that the drug delivery system has broad-spectrum controlled-release performance for different types of molecules, and the controlled-release time can exceed 40 h. At the same time, the pH- responsive property of the sodium alginate hydrogel endows the delivery system with a certain targeting function. This study provides a new strategy for constructing an efficient targeted drug controlled-release system.

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.

Water-resistant and pyknotic recyclable waste-cotton-derived bio-polyurethane-coated controlled-release fertilizer: Improved longevity, mechanism and application

Reasonably utilize the recyclable waste-cotton resource to develop the bio-polyurethane coatings had aroused more and more environmental interests recently. However, the terrible water resistance and porousness of the waste-cotton-derived bio-polyurethane coating caused the rapid nutrients release. In this work, the water-resistant and pyknotic cotton-fibre-derived coated-ureas (WPCUs) were fabricated with the recyclable low-cost waste-cotton-derived materials. The dramatically enhanced pyknotic and water-resistant characteristics of the WPCUs coatings can be obtained by the three-dimensional computerized tomography (2.33 to 1.19 %) and the water contact angle. The enhanced elasticity and the decreased water absorption were also vital to enhance the controlled-release performance. The accompanying controlled-release performance of the WPCUs was obviously improved (<2 h to 58.43 days). The modified WPCU75–10 with 4.0 % coating content exhibits the excellent controlled-release performance compared to the unmodified WPCU0–0. The controlled release mechanism can be clarified: The air column inside of the “small and few” micropores in the WPCUs coating only allow the gaseous water molecules to slowly penetrate and dissolve the inner urea cores (rather than liquid water). The obviously increased oilseed rape yield (128.75 %) showed the dependable agricultural application of the WPCUs. This work provides the resultful approach to develop the eco-friendly recyclable waste-plant-derived controlled-release fertilizers.

Effect of freeze drying and spray drying on physical properties, morphology and in vitro release kinetics of vitamin D3 nanoparticles

Encapsulation is a viable and effective technique for protection and stability of vitamin D3 during processing. In the present experiment, the effect of ultrasonication on encapsulation of vitamin D3 using gum arabic was studied. Nanoreduction of gum arabic emulsion largely increased the encapsulation profile of the process. Freeze drying and spray drying methods were employed for the drying of vitamin D3 nanoemulsions to obtain powdered encapsulates. Powders obtained by both techniques were analyzed in terms of physical properties, surface morphology, encapsulation efficiency and in vitro release kinetics. Parameters such as moisture content, product yield, encapsulation efficiency, particle size and zeta potential showed significant difference (p ≤ 0.05). While comparing release behavior, spray dried encapsulates presented better controlled release performance than freeze dried encapsulates. The findings revealed that spray drying technique present a better scope for encapsulating vitamin D3 due to its better encapsulation efficiency and release than freeze drying technique.