pH-responsive Controlled Release Research Articles

Self-assembly metal phenolic network coating improves the controlled release and bacteriostatic properties of Litsea cubeba essential oil-loaded ε-polylysine-pectin nanoparticles

Pectin and ε-polylysine (ε-PL) nanoparticles loaded with Litsea cubeba essential oil (LEO) (PP-LNPs) were prepared through the electrostatic interaction. Metal phenol network (MPN) coatings, designated as MPN@PP-LNPs, were fabricated on the surface of the nanoparticles via self-assembly process of tannic acid (TA) and FeIII to develop food preservative materials with pH-responsive controlled release. The morphology, encapsulation efficiency, and pH-responsive release characteristics of MPN@PP-LNPs were investigated. The results showed that the particle size of MPN@PP-LNPs was 432.5 ± 58.6 nm. Furthermore, the encapsulation efficiencies of ε-PL and LEO were 83.26 ± 2.21% and 30.78 ± 3.92%, respectively. TA was rapidly released at low pH, while LEO exhibited controlled release over a wide pH range (pH 1.2–9.0). In addition, the MPN coating has been demonstrated to enhance antioxidant activity and inhibit the growth of E. coli and S. aureus under acidic conditions. Furthermore, preliminary evidence suggests that MPN@PP-LNPs are not cytotoxic. In conclusion, MPN@PP-LNPs, prepared through the self-assembled surface modification of TA and FeIII, was an effective material for food preservation.

Ti2C3 MXene-based nanocomposite as an intelligent nanoplatform for efficient mild hyperthermia treatment

Photothermal therapy (PTT) has attracted much attention due to its less invasive, controllable and highly effective nature. However, PTT also suffers from intrinsic cancer resistance mediated by cell survival pathways. These survival pathways are regulated by a variety of proteins, among which heat shock protein (HSP) triggers thermotolerance and protects tumor cells from hyperthermia-induced apoptosis. Confronted by this challenge, we propose and validate here a novel MXene-based HSP-inhibited mild photothermal platform, which significantly enhances the sensitivity of tumor cells to heat-induced stress and thus improves the PPT efficacy. The Ti3C2@Qu nanocomposites are constructed by utilizing the high photothermal conversion ability of Ti3C2 nanosheets in combination with quercetin (Qu) as an inhibitor of HSP70. Qu molecules are loaded onto the nanoplatform in a pH-sensitive controlled release manner. The acidic environment of the tumor causes the burst-release of Qu molecules, which deplete the level of heat shock protein 70 (HSP70) in tumor cells and leave the tumor cells out from the protection of the heat-resistant survival pathway in advance, thus sensitizing the hyperthermia efficacy. The nanostructure, photothermal properties, pH-responsive controlled release, synergistic photothermal ablation of tumor cells in vitro and in vivo, and hyperthermia effect on subcellular structures of the Ti3C2@Qu nanocomposites were systematically investigated.

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.

A fluorescent system based on graphene quantum dots-capped magnetic hydroxyapatite-MIL-100 metal-organic frameworks for pH-sensitive and controlled release of DOX

Since metal-organic frameworks (MOFs) have shown great potential as emerging candidates in biomedical applications, it is worthwhile to construct an MOF-based drug delivery system. Hence, in this work, magnetic hydroxyapatite-MIL-100 metal-organic frameworks (SiO2@Fe3O4-HA-MIL-100) with antioxidant properties were synthesized as a novel drug delivery system through in-situ self-assembly of MIL-100 MOFs around pre-synthesized magnetic hydroxyapatite nanoparticles. Then, SiO2@Fe3O4-HA-MIL-100 nanocomposites were capped with fluorescent graphene quantum dots (SiO2@Fe3O4-HA-MIL-100-GQDs) for loading and delivering of doxorubicin (DOX). The SiO2@Fe3O4-HA-MIL-100, GQDs, and SiO2@Fe3O4-HA-MIL-100-GQDs encapsulation efficiency was 80.2, 42.2, and 95.8 %, respectively. The in vitro DOX release amount after 72 h from SiO2@Fe3O4-HA-MIL-100, GQDs, and SiO2@Fe3O4-HA-MIL-100-GQDs at pH 5 was 75.8 %, 86.2 %, and 67.2 %, while at pH 7.4 was 37.3 %, 50.1 %, and 29 %, respectively. These results confirmed a pH-responsive controlled release of DOX from nanocomposites. The release mechanism of DOX from the prepared nanocomposites was also well fitted to the Korsmeyer-Peppas kinetic, Fickian diffusion, and diffusion-controlled release. In addition, the MTT assays of nanocomposites against MCF-7 breast cancer cell lines clearly illustrated that the prepared nanocomposites had no significant cytotoxicity, while DOX-loaded nanocomposites had notable toxicity to MCF-7 cells. The IC50 values of DOX, SiO2@Fe3O4-HA-MIL-100-DOX, GQDs-DOX, and SiO2@Fe3O4-HA-MIL-100-GQDs-DOX against MCF-7 cells calculated at about 4.2 μg/mL, 1.8 μg/mL, 3 μg/mL, and 1.2 μg/mL, respectively. The DPPH test results also showed that the nanocomposites have excellent antioxidant activity. In addition, the in vitro hemolysis results displayed neglectable hemolysis activity (lower than 5 %) of SiO2@Fe3O4-HA-MIL-100-GQDs even at a high dose. Therefore, these new drug delivery systems can be used safely as potential drug carriers in targeted cancer therapy.

PH-sensitive biosystem based on laponite RD/chitosan/polyvinyl alcohol hydrogels for controlled delivery of curcumin to breast cancer cells

In this study, a pH-responsive hydrogels based on laponite rapid dispersion (Lap®)/chitosan (CS)/polyvinyl alcohol (PVA) designed and was used for controlled delivery of the anticancer drug curcumin (CUR). First, it was accomplished by dissolving CUR in Lap® dispersion under the influence of the pH of the environment. Then, in the presence of Lap®CUR cross-linking was incorporated between CS and PVA polymers. The structural features of Lap®CUR/CS@PVA hydrogels are characterized using FT-IR, XRD, SEM/EDS, TEM, TGA, Zeta potential, and XPS. The in vitro drug release profiles confirmed a pH-responsive controlled release of CUR in acidic pH for all hydrogels. During 12 h, the cumulative release of CUR from Lap®CUR/0.1CS@PVA hydrogel was 27.9% and 12.3%, at pH 5.5 and 7.4, respectively. While during three days the release rate reached 48.5% and 18.5%. The CUR release kinetic from hydrogels also suggests that the kinetic data well fitted to the Korsmeyer-Peppas, diffusion-controlled and Fickian diffusion. Furthermore, in vitro cytotoxicity and DAPI staining study clearly illustrated that Lap®CUR/0.1CS@PVA hydrogel had lower cytotoxicity than CUR against MDA-MB 231 cancer cells, which confirmed the controlled release of drug through hydrogels. Meanwhile, in vitro hemolysis, antioxidant and antibacterial tests revealed that the prepared hydrogels have good blood compatibility, excellent antioxidant properties, and antibacterial activity. Based on the obtained results, the designed hydrogels could be potentially applied as pH-controlled drug delivery systems for cancer therapy.

PH-Activatable Charge-Reversal Polymer-Based Nanocarriers for Targeted Delivery of Antihepatoma Compound.

Chemotherapy is one of the available cancer treatments which has been successfully employed to prolong the survival of cancer patients. However, it remains a major challenge to develop effective chemotherapeutic agents by reducing off-target toxicity, improving bioavailability, and effectively prolonging blood circulation. The pH profile of tumor cells is abnormal to that of normal cells, making it a potential breakthrough for designing effective chemotherapeutic drug agents. Here, the pH-activatable charge-reversal supramolecular nanocarriers, named MI7-β-CD/SA NPs, were prepared through a simple and "green" constructive process. MI7-β-CD/SA NPs possess both pH-induced charge-reversal and disassembly properties that were exploited to investigate the loading, delivery, and pH-responsive controlled release of the antitumor compound celastrol (CSL). CSL@MI7-β-CD/SA NPs displayed low hemolysis, good biocompatibility, and targeted uptake. Furthermore, CSL@MI7-β-CD/SA NPs exhibited superior apoptosis rates against SMMC-7721 cell lines compared with CSL, when CSL@MI7-β-CD/SA NPs and CSL were administered at a mass concentration of 5.0 μg/mL, i.e., the CSL content in CSL@MI7-β-CD/SA NPs was relatively lower than that of intact CSL. We expected that MI7-β-CD/SA NPs featuring pH-triggered charge reversal could offer a promising controlled release strategy that would then facilitate the clinical conversion of antitumor drugs.

Intelligent anti-corrosion coating with multiple protections using active nanocontainers of Zn[sbnd]Al LDH equipped with ZIF-8 encapsulated environment-friendly corrosion inhibitors

The incalculable metal corrosion loss makes the research of long-term corrosion resistant coatings attract much attention. Herein, we demonstrated a new strategy for constructing a pH-responsive nanocontainer as a gatekeeper, which consisted of a laminated double hydroxide (LDH) surface in situ grown ZIF-8 containing the corrosion inhibitor of 2-mercaptobenzimidazole (MBM). The shell-core structures of the composite fillers displayed the excellent barrier performance and pH-responsive controlled release properties in epoxy (EP) coatings. Electrochemical impedance spectroscopy and salt spray tests were conducted to investigate the multifunctional role in providing an intelligent anti-corrosion MBM@ZIF-8@LDH/EP composite coating. After immersing in salt solution (3.5 wt%) for 30 days, the impedance value of the MBM@ZIF-8@LDH/EP coating at 0.01 Hz (|Z|0.01 Hz) was 2.82 × 108 Ω∙cm2, which was about four orders of magnitude higher than that of the epoxy coating (1.54 × 104 Ω∙cm2). The outstanding corrosion protection of MBM@ZIF-8@LDH was attributed to not only the compactness improvement of the composite coating, but also the anion exchange capability to act as a storage station for chloride ions. Meanwhile, the active filler could be used as a pH-responsive nanocontainer to release the loaded corrosion inhibitor of MBM and prevented further damage to the steel substrate, displaying a self-healing behavior. This strategy provides a new idea to combine perfect barrier effect and active anti-corrosion performance to prepare high-performance anti-corrosion and self-healing coatings. The multi-protective smart anti-corrosive coating would be a candidate with excellent performance for use in a variety of fields.

Metal–organic framework- and graphene quantum dot-incorporated nanofibers as dual stimuli-responsive platforms for day/night antibacterial bio-protection

Development of advanced antibacterial nanomaterials is important to prevent pathogenic microbial contamination and achieve bioprotection. Herein, we developed dual-stimuli-responsive nanoplatforms with efficient antibacterial activity based on electrospun polycaprolactone/hydroxypropyltrimethylammonium chloride chitosan (PQ) nanofiber membranes (NFMs) incorporated with naringenin-loaded zeolitic imidazolate framework-8 (NAR@ZIF-8) and graphene quantum dots (GQDs). These NFM nanoplatforms could simultaneously be used as “smart” pH-responsive controlled-release and photocatalytic systems. NAR was encapsulated in the microporous structure of the ZIF-8 channel, with a loading capacity of 22.57%. NAR@ZIF-8- and GQD-incorporated PQ (PQZG) nanofibers exhibited enhanced thermal stability and mechanical properties. The release kinetics and microstructure of the nanocarriers demonstrated that the acid-sensitive cleavable crystal structure of ZIF-8 resulted in the pH-responsive release of NAR from PQZG NFMs. Moreover, the presence of GQDs significantly enhanced the photoinduced reactive oxygen species (ROS) generation by NFMs. pH-triggered NAR release and photoinduced ROS generation improved the antibacterial efficacy of PQZG NFMs, forming the synergetic chemical-photodynamic strategies of the dual stimuli-responsive nanoplatforms. Additionally, cytotoxicity experiments revealed that the PQZG NFMs were non-toxic and had good biocompatibility. Therefore, the designed composite nanomaterials combined with the two antibacterial strategies can aid in the development of biosafe nanofibrous membranes for antibacterial or multifunctional bio-protection.

Development of a smart anticorrosion epoxy coating containing a pH-sensitive GO/MOF nanocarrier loaded with 2-mercaptobenzothiazole corrosion inhibitor

This study investigated a smart epoxy-polyamide coating containing graphene oxide (GO) modified with a metal-organic framework nickel/2-methylimidazole (Ni-MOF) as a nanocarrier with a pH-responsive controlled release system. Then, 2-mercaptobenzothiazole (MBT) as a corrosion inhibitor was encapsulated within the nanocarrier (GMOFM). FT-IR, XRD, EDX, and TGA analysis of nanoparticles indicated successful preparation of GO modified Ni-MOF and encapsulation of MBT within the nanocarrier. FESEM and TEM images of nanoparticles showed spherical structures for Ni-MOF and effective modification of planar GO with Ni-MOF. Moreover, the BET test illustrated synthesized nanoparticles' porous structure and high surface area with 20 nm average pore diameters. EIS and salt spray tests of a GMOFM nanocomposite coating exhibited that GMOFM improved the coating's protective performance and endowed it with self-healing behavior. Unlike the neat EP, the |Z| value at 10 mHz of the GMOFM/EP remains greater than 1011 Ω cm2 (only a 2.75% drop) even after 63 days of immersion. In addition, after 96 h of immersion in a 3.5 wt% NaCl solution, scratched coatings EIS revealed that the charge transfer resistance of the GOMFM/EP was approximately six times greater than that of the neat EP. This superior protection and self-healing ability can be credited to the blocking effect of GO/MOF, the excellent compatibility of GMOFM, and the synergistic effect of the Ni-MOF particle and MBT corrosion inhibitor that can release corrosion inhibitor and provide corrosion protection film via a pH-responsive mechanism.

Newly developed nano-biocomposite embedded hydrogel to enhance drug loading and modulated release of anti-inflammatory drug

A newly developed iron-based nano-biocomposite (nano Fe-CNB) impregnated alginate formulation (CA) is proposed to improve drug loading and exhibit pH-responsive behavior of model anti-inflammatory drug-ibuprofen for controlled release applications. The proposed formulation is investigated with conventional β-CD addition in CA. The nano Fe-CNB-based formulations with and without β-CD, (Fe-CNB β-CD CA and Fe-CNB CA) are compared with only CA and β-CD incorporated CA formulations. The results indicate the incorporation of nano-biocomposite or β-CD into CA enhances the drug loading (>40%). However, pH-responsive controlled release behavior is observed for nano Fe-CNB based formulations only. The release studies from Fe-CNB β-CD CA indicate ∼ 45% release in stomach pH (1.2) within 2 h. In contrast, Fe-CNB CA shows ∼20% release only in stomach pH and improved release (∼49%) at colon pH (7.4). The rheology and swelling studies indicate Fe-CNB CA remains intact in stomach pH with a minimal drug release, but it disintegrates at colon pH due to charge reversal behavior of nano-biocomposite and ionization of polymeric chains. Thus, Fe-CNB CA formulation is found to be a potential candidate for targeting colon delivery, inflammatory bowel disease, and post-operative conditions.

Exploring the robustness of DNA nanotubes framework for anticancer theranostics toward the 2D/3D clusters of hypopharyngeal respiratory tumor cells

This study aimed to develop a robust approach for the early diagnosis and treatment of tumors. Short circular DNA nanotechnology synthesized a stiff and compact DNA nanotubes (DNA-NTs) framework. TW-37, a small molecular drug, was loaded into DNA-NTs for BH3-mimetic therapy to elevate the intracellular cytochrome-c levels in 2D/3D hypopharyngeal tumor (FaDu) cell clusters. After anti-EGFR functionalization, the DNA-NTs were tethered with a cytochrome-c binding aptamer, which can be applied to evaluate the elevated intracellular cytochrome-c levels via in situ hybridization (FISH) analysis and fluorescence resonance energy transfer (FRET). The results showed that DNA-NTs were enriched within the tumor cells via anti-EGFR targeting with a pH-responsive controlled release of TW-37. In this way, it initiated the triple inhibition of “BH3, Bcl-2, Bcl-xL, and Mcl-1”. The triple inhibition of these proteins caused Bax/Bak oligomerization, leading to the perforation of the mitochondrial membrane. This led to the elevation of intracellular cytochrome-c levels, which reacted with the cytochrome-c binding aptamer to produce FRET signals. In this way, we successfully targeted 2D/3D clusters of FaDu tumor cells and achieved the tumor-specific and pH-triggered release of TW-37, causing tumor cell apoptosis. This pilot study suggests that anti-EGFR functionalized, TW-37 loaded, and cytochrome-c binding aptamer tethered DNA-NTs might be the hallmark for early tumor diagnosis and therapy.

PH-Responsive Intelligent Antibacterial Coatings Based on 2D-COF for Controlled Release of Capsaicin

Herein, we designed and synthesized a two-dimensional covalent organic framework (2D-COF) of a Schiff base using a mechanical chemical grinding method. Moreover, capsaicin@chitosan (CAP@CS) microcapsules were loaded on a TpPa-1 COF by a physical adsorption method to prepare composites (CAP@CS/TpPa-1), which realized the pH-sensitive controlled release of the fungicide CAP, dispersed in fluorocarbon resin to prepare an intelligent coating with environmentally friendly long-term antifouling performance. TpPa-1 improves the antibacterial efficiency by increasing the dispersity of CAP@CS in the resin. Therefore, a CAP release amount of 2 wt % composite coating can meet the minimum bacteriostatic concentration of 37.5 μg/mL required for antifouling. Importantly, pH-responsive controlled release caused by the protonation of CS and the electrostatic interaction between CAP@CS and TpPa-1 COF and increased bacterial contact area by CAP@CS reunion inhibited by TpPa-1 COF improve the bactericidal efficiency of the composite. The composite coating has excellent corrosion resistance, mainly because COF extends the propagation path of the corrosive medium.

Mussel-inspired self-healing hydrogel based on gelatin and oxidized tannic acid for pH-responsive controlled drug release

A series of mussel-inspired pH-responsive self-healing hydrogels based on gelatin crosslinked by oxidized tannic acid (GLT-OTAs) were prepared and used as controlled drug delivery systems (CDDS). An antiphlogistic drug, indomethacin (IDMC) was used as model drug to be immobilized into the hydrogels. The obtained hydrogel samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Mechanical stability, biocompatibility and self-healing property of the hydrogels were estimated, respectively. Swelling and drug release behaviors of these hydrogels were measured in phosphate buffered saline (PBS) with pH 7.4 (simulated intestinal fluid) and HCl solution with pH 1.2 (simulated gastric fluid) at 37 °C. Effect of the OTA content on the structures and characteristics of all samples was discussed. FTIR spectra revealed the covalent cross-linking between gelatin and OTA induced by Michael addition and Schiff base reaction. Both XRD and FTIR all showed the drug (IDMC) was loaded successfully and existed steadily. GLT-OTA hydrogels had satisfactory biocompatibility, superior self-healing. Results also illustrated that the mechanical strength, internal structure, the swelling and drug release behaviors of the GLT-OTAs hydrogel were greatly affected by the OTA content. With increasing the OTA content, the mechanical stability of GLT-OTAs hydrogel became better and better, and their internal structure became more and more compact. The swelling degree (SD) and cumulative drug release of all hydrogel samples tended to decrease with increasing OTA content and both had obvious pH responsiveness. For each hydrogel sample, the cumulative drug release in PBS at pH 7.4 was greater than that in HCl solution at pH 1.2. These results indicated that the obtained GLT-OTAs hydrogel had promising potential to be used as effective pH-responsive and self-healing drug delivery materials.

Fabrication of biocompatible magnetic maltose/MIL-88 metal–organic frameworks decorated with folic acid-chitosan for targeted and pH-responsive controlled release of doxorubicin

Recently, metal–organic frameworks (MOFs) have attracted tremendous attention as promising porous drug delivery systems for cancer treatment. In this work, for the first time, a novel magnetic maltose disaccharide molecule modified with MIL-88 metal–organic framework (Fe3O4@C@MIL-88) was prepared, and then this targeted system was used for the delivery of the doxorubicin (DOX) drug. Eventually, Fe3O4@C@MIL-88-DOX were successfully decorated with folic acid conjugated chitosan (Fe3O4@C@MIL-88-DOX-FC) as a new targeted and controlled release drug system for treatment of MCF-7 breast cancer. The encapsulation efficiency of the DOX in the Fe3O4@C@MIL-88 was obtained at ∼83.6%. The in vitro drug release profiles showed a pH-responsive controlled release of DOX in acidic pH confirming the performance of the systems in the cancerous environment. The DOX release mechanism from systems at pH 5 also showed that the kinetic data well fitted to the Korsmeyer-Peppas and Fickian diffusion. Furthermore, in vitro cytotoxicity and DAPI staining study clearly illustrated that the synthesized Fe3O4@C@MIL-88 system had low cytotoxicity and good biocompatibility against MCF-7 cancer cells and MCF-10A normal cells. Whereas, Fe3O4@C@MIL-88-DOX and Fe3O4@C@MIL-88-DOX-FC exhibited good antitumor activity as a result of targeted delivery of DOX, which indicated the MCF-7 cell death with apoptotic effects. Based on these findings, the resulting carriers could be used as promising targeted drug delivery systems for cancer therapy.

Novel targeted pH-responsive drug delivery systems based on PEGMA-modified bimetallic Prussian blue analogs for breast cancer chemotherapy.

The development of novel nanoparticle-based drug delivery systems (nano-DDSs) with high loading capacity, low toxicity, precise targeting, and excellent biocompatibility remains urgent and important for the treatment of breast cancer (BC). Herein, novel BC-targeted nano-DDSs based on bimetallic Prussian blue analogs (PBA-DDSs) for intracellular doxorubicin (DOX) delivery and pH-responsive release were developed. Two kinds of bimetallic PBA, namely CuFe (copper-iron) PBA and CoFe (cobalt-iron) PBA, were synthesized by a coprecipitation method, followed by modification with polyethyleneglycol methacrylate (PEGMA) via surface-initiated atom transfer radical polymerization and immobilization with the AS1411 aptamer to obtain two kinds of novel BC-targeted nano-DDS. CuFePBA@PEGMA@AS1411 and CoFePBA@PEGMA@AS1411 showed high drug loading efficiency of 80% and 84%, respectively, for DOX, while 56.0% and 75.9% DOX release could be achieved under acidic pH conditions. In vitro cell viability and in vivo experiments proved the good biocompatibility of both PBA-DDSs. Cellular uptake and in vivo distribution suggested that both PBA-DDSs had efficient nucleolin-targeting capability, indicating the targeted delivery of DOX in tumor tissues. In vivo evaluation of anti-BC efficacy further confirmed that the obtained PBA-DDSs exhibited excellent therapeutic efficacy with limited side-effects. Therefore, the proposed novel PBA-DDSs can be used as secure and effective drug nano-DDSs for BC chemotherapy.

Synthesis of stable calcium carbonate nanoparticles for pH-responsive controlled drug release

The construction of controlled release for drugs is a promising strategy in disease treatment, which can improve the bioavailability of utilized drugs and reduce the side effects. Herein, a simple and green strategy was developed to prepare stable amorphous calcium carbonate (ACC) using polyvinyl pyrrolidone (PVP) as stabilizer. The crystallization behavior of ACC nanoparticles in methanol–water system and the effect of PVP content on ACC was investigated. Most importantly, the obtained ACC-PVP exhibited high drug loading efficiency and pH responsive release properties for anticancer drugs 5-Fluorouracil (5-FU) and curcumin (CUR) in phosphate buffer solution and simulated gastric juice. All evidences demonstrate that smart mesoporous ACC-PVP nanoparticles provide a potential clinical application platform for cancer therapy.

Carboxymethyl Chitosan-Modified Graphene Oxide as a Multifunctional Vector for Deltamethrin Delivery and pH-Responsive Controlled Release, Enhanced Leaf Affinity, and Improved Mosquito-Killing Activity.

Traditional deltamethrin (DM) formulations (e.g., emulsifiable concentrates, wettable powders, etc.) have significant disadvantages of poor water dispersion stability, burst release, weak leaf affinity, short duration, poor efficacy, and high environmental toxicity. A nanomaterial-based pesticide delivery system (PDS) has provided effective strategies for green preparation and synergism of pesticide formulations. In this article, we developed carboxymethyl chitosan (CMCS)-modified graphene oxide (GO) as a vector for DM and constructed a pH-responsive PDS for Culex pipiens pallens control. GO-CMCS possesses excellent pesticide loading performance for DM (loading rate 87.76%). After being loading on GO-CMCS, the GO-CMCS-DM has a significantly improved dispersion stability in water. The GO-CMCS-DM exhibits pH-responsive controlled release performance, which can sustain the release of DM into the medium, maintaining an effective long-term concentration. Additionally, the leaf adhesion of GO-CMCS-DM is better than that for free DM, which can improve the pesticide utilization. Therefore, GO-CMCS-DM has a prolonged persistent period and sustained activity against Culex pipiens pallens. Considering the industrialization potential of GO, we believe that GO will play an important role in the pest control and antiepidemic fields.

Programmable Drug Release from a Dual-Stimuli Responsive Magnetic Metal–Organic Framework

Along with the increasing incidence of cancer and drawbacks of traditional drug delivery systems (DDSs), developing novel nanocarriers for sustained targeted-drug release has become urgent. In this regard, metal–organic frameworks (MOFs) have emerged as potential candidates due to their structural flexibility, defined porosity, lower toxicity, and biodegradability. Herein, a FeMn-based ferromagnetic MOF was synthesized from a preassembled Fe2Mn(μ3-O) cluster. The introduction of the Mn provided the ferromagnetic character to FeMn-MIL-88B. 5-Fluoruracil (5-FU) was encapsulated as a model drug in the MOFs, and its pH and H2S dual-stimuli responsive controlled release was realized. FeMn-MIL-88B presented a higher 5-FU loading capacity of 43.8 wt % and rapid drug release behavior in a tumor microenvironment (TME) simulated medium. The carriers can rapidly release loaded drug of 70% and 26% in PBS solution (pH = 5.4) and NaHS solution (500 μM) within 24 h. The application of mathematical release models indicated 5-FU release from carriers can be precisely fitted to the first-order, second-order, and Higuchi models of release. Moreover, the cytotoxicity profile of the carrier against human embryonic kidney cells (HEK293T) suggests no adverse effects up to 100 μg/mL. The lesser toxic effect on cell viability can be attributed to the low toxicity values [LD50 (Fe) = 30 g·kg–1, (Mn) = 1.5 g·kg–1, and (terephthalic acid) = 5 g·kg–1] of the MOFs structural components. Together with dual-stimuli responsiveness, ferromagnetic nature, and low toxicity, FeMn-MIL-88B MOFs can emerge as promising carriers for drug delivery applications.

Environmentally Friendly Zr-Based MOF for Pesticide Delivery: Ultrahigh Loading Capacity, pH-Responsive Release, Improved Leaf Affinity, and Enhanced Antipest Activity.

The stimuli responsive pesticide delivery system (PDS) has drawn increasing attention in recent years, a system which can effectively improve the utilization of pesticides. In the current research, we report a pH responsive PDS by using carboxymethyl cellulose (CMC) modified Zr-based metal organic frameworks (UiO-66-NH2) as the nanocarrier for acetamiprid (ATP). UiO-66-NH2-CMC possesses a large surface area and abundant pores, which can effectively load ATP, and the loading rate is as high as 90.79%. Compared with free ATP, the ATP@UiO-66-NH2-CMC nanopesticide exhibits pH responsive controlled release behavior, and the pesticide can sustained release to the medium. In addition, it also shows improved leaf affinity, which makes it easier to wet the leaf surface and improve the utilization of pesticide. Therefore, ATP@UiO-66-NH2-CMC displays better antipest activity against aphids than free ATP does. Meanwhile, ATP@UiO-66-NH2-CMC shows no negative effects on the germination and growth of maize, showing good biosafety. Moreover, the ATP@UiO-66-NH2-CMC nanopesticide does not contain any toxic organic solvents or additives. Therefore, we hope that it can be a suitable candidate for plant protection and sustainable agriculture.

Construction of Prochloraz-Loaded Hollow Mesoporous Silica Nanoparticles Coated with Metal-Phenolic Networks for Precise Release and Improved Biosafety of Pesticides.

Currently, environmental-responsive pesticide delivery systems have become an essential way to improve the effective utilization of pesticides. In this paper, by using hollow mesoporous silica (HMS) as a nanocarrier and TA-Cu metal–phenolic networks as a capping agent, a pH-responsive controlled release nano-formulation loaded with prochloraz (Pro@HMS-TA-Cu) was constructed. The structure and properties of Pro@HMS-TA-Cu were adequately characterised and analysed. The results showed that the loading content of Pro@HMS-TA-Cu nanoparticles was about 17.7% and the Pro@HMS-TA-Cu nanoparticles exhibited significant pH-responsive properties. After a coating of the TA-Cu metal–phenolic network, the contact angle and adhesion work of Pro@HMS-TA-Cu nanoparticles on the surface of oilseed rape leaves after 360 s were 59.6° and 107.2 mJ·m−2, respectively, indicating that the prepared nanoparticles possessed excellent adhesion. In addition, the Pro@HMS-TA-Cu nanoparticles demonstrated better antifungal activity against Sclerotinia sclerotiorum and lower toxicity to zebrafish compared to prochloraz technical. Hence, the pH-responsive nanoparticles prepared with a TA-Cu metal–phenolic network as a capping agent are highly efficient and environmentally friendly, providing a new approach for the development of new pesticide delivery systems.