pH Dual Responsiveness Research Articles

Temperature and pH dual response flexible silica aerogel with switchable wettability for selective oil/water separation

Silica aerogels are attractive oil-absorbing agents due to their low density, high porosity. However, how to discharge the oil which adsorbed by silica aerogels is a difficult issue. To address this challenge, new separation strategies with high efficiency are needed. In this study, we prepared the temperature and pH dual response flexible silica aerogel have temperature response and pH response effect, which can change its wettability by adjusting temperature or pH. On the one hand, the temperature and pH responsive flexible silica aerogel can be used to adsorb water at the temperature below 34.73 °C or pH > 7. On the other hand, it can adsorb oil at a temperature above 34.73 °C or pH < 7. The automatic desorption of oil can be achieved without consuming additional energy and damaging the pore structure. Therefore, the sample could continuously adsorb and filtrate efficiently and realize the recovery of oil and adsorption materials.

A multifunctional nanoplatform for precision-guided therapeutic intervention in bacterial infection.

Skin wound infection has become a global clinical problem in recent years. Curcumin (Cur) and polylysine (PLL) are natural products with strong antibacterial properties. However, the poor water solubility and low stability of Cur and the cationic toxicity of PLL limit their application. In this study, we synthesized a macromolecular hyaluronic acid (HA)-curcumin drug (HC) via esterification. HC was attracted by electrostatic interactions with positively charged PLL to form a spherical nanocomplex (HCP) with hyaluronidase (HAase) and pH dual response under ultrasonication. HCP was found to target the bacterial infection microenvironment and release Cur and PLL for synergistic antibacterial action. In addition, HCP was proven to exhibit good biocompatibility and broad spectrum antibacterial activity to bacterial strains S. aureus and E. coli and antibacterial biofilm activities in vitro. In vivo experiments showed that HCP could inhibit pathogens and promote wound healing. These results prove that HCP can be used as a new strategy for the treatment and management of infected wounds.

Redox and pH Dual-Responsive Polypeptide Micelles for Doxorubicin Delivery with Enhanced Anticancer Efficacy

Herein, redox and pH dual-responsive poly(glutamic acid) micelle-encapsulated doxorubicin (DOX) was developed in this report. First, methoxy poly(ethylene glycol)-block-poly(glutamic acid) (PEG-SS-PG) linked by a disulfide bond was synthesized through ring-opening polymerization of l-glutamic acid γ-benzyl ester carboxyanhydride using terminal aminosylated poly(ethylene glycol) (PEG-SS-NH2) as an initiator. After that, PEG-SS-PG was assembled with doxorubicin (DOX) by a simple mixing to form tight PEG-SS-PG/DOX micelles by virtue of the electrostatic interaction between carboxylic acid groups of PEG-SS-PG and amine groups of DOX. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) characterization indicated that the micelles have a spherical structure with an average particle size of about 70 nm. The drug loading efficiency (DLE) was measured to be 92.3 wt %. The release behavior of PEG-SS-PG/DOX was checked in the presence of glutathione (GSH) and different pH. The results showed that about 90% DOX was released within 36 h under the combined action of high GSH concentration and low pH, while less than 25% DOX was released at pH 7.4 in the absence of GSH. These data confirmed the glutathione and pH dual-responsiveness of PEG-SS-PG/DOX micelles. The micelles could be internalized by cancer cells, as revealed by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM). The pharmacokinetics and biodistribution of the PEG-SS-PG/DOX micelles were further investigated in detail. Compared with free DOX, PEG-SS-PG/DOX micelles improved the biodistribution of DOX and prolonged blood circulation time. Finally, in vivo antitumor efficacy was studied using 4T1 breast tumor-bearing BALB/c mice. It was found that the tumor inhibition rate of PEG-SS-PG/DOX was up to 86.32%, indicating greatly effective antitumor performance. Taken together, PEG-SS-PG micelles can encapsulate DOX via electrostatic interaction to form tight micelles and possess redox and pH dual-responsive release of DOX and highly effective inhibition of tumor growth, which have potential application for the treatment of tumors.

Self-crosslinked keratin nanoparticles for pH and GSH dual responsive drug carriers

Nano-drug delivery system (NDDS) has attracted widespread attention for their controlled drug release. In this work, keratin nanoparticles (KNPs) were prepared by self-crosslinking. No toxic chemical crosslinkers were added in the whole procedure. The morphology and size of KNPs were tested by transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The KNPs exhibited GSH and pH dual responsiveness as well as charge conversion, which were beneficial to tumor therapy. In addition, the anticancer drug of doxorubicin (DOX) could be loaded on KNPs by hydrophobicity and hydrogen bonds. The drug-loaded keratin nanoparticles (KDNPs) accelerated drug release under mimicked tumor microenvironments. In addition, KDNPs could effectively inhibit tumor cell growth while performing low toxicity on normal cells. Moreover, KDNPs could be uptaken by tumor cells through endocytosis. Based on the results, keratin-based nanoparticles were suitable candidates for drug microcarriers.

MoS2@C nanosphere as near infrared / pH dual response platform for chemical photothermal combination treatment

The three-dimensional urchin-like MoS2@C nanocomposite was successfully synthesized via one-step hydrothermal synthesis approach. The as-prepared MoS2@C nanoparticles exhibits strong absorb, high photothermal conversion ability (40.8 %), superb biocompatibility and high drug loading capacity for doxorubicin (52.34 %). In vitro drug release experiments show a pH, temperature and near infrared laser-triggered doxorubicinhydro release profile that enhances therapeutic anticancer effects. The drug release curve increased step by step under laser irradiation, and the accumulative delivery amount reached to 64.59 %, which was about 2 times of that without laser irradiation. By using DOX-loaded nano-platform, effective synergistic photothermal therapy for cancer can be achieved and has been systematically verified in vitro. Cell viability experiments showed that the survival rate of cells with MoS2 @C-DOX was only 25.8 %. Therefore, this work presents carbon-based nanoparticles with significant characteristics and is used as a highly potential therapeutic nano-platform for cancer treatment.

Hollow S-nitrosothiols nanoparticle with polymeric brushes for nitric oxide (NO)-releasing as tumor targeted chemotherapy

A kind of tumor targeting nitric oxide donor nanoparticle with brushes is described in this paper. The poly(4-vinylphenylboronic acid) polymeric brush, which shows glucose and pH dual responsiveness, endows the ability of hollow S-nitrosothiols nanoparticle to accurate recognition and binding with the sialic acid over-expressed type tumor cells, such as HepG2 and MCF-7 cells. In vitro experiments, including cells capture and release experiments, confocal fluorescence microscope characterization, cytotoxicity assay with different cells, demonstrate the selective recognition and the controlled NO release to kill tumor cells for these S-nitrosothiols nanoparticles. Low concentration of the released NO from the S-nitrosothiols nanoparticles in the transmission would participate physiological activity and avoid serious side effects because the endogenous nature and the physiological necessity to regulate normal biological functions. To the best of our knowledge, this is the first report about polymer nanoparticles as NO donors with functional brushes to selectively identify tumor cells and release NO in a controlled manner.

A magnetic polypeptide nanocomposite with pH and near-infrared dual responsiveness for cancer therapy

A magnetic polypeptide nanocomposite with pH and near-infrared (NIR) dual responsiveness was developed as a drug carrier for cancer therapy, which was prepared through the self-assembly of Fe3O4 superparamagnetic nanoparticles, poly(aspartic acid) derivative (mPEG-g-PDAEAIM) and doxorubicin (DOX) in water. Fe3O4 nanoparticles were prepared to provide the superparamagnetic core of nanocomposites for tumor targeting via chemical co-precipitation. The protonable imidazole groups of mPEG-g-PDAEAIM with a pKa of ~7 were accountable for the pH-responsiveness of nanocomposites. The photothermal effect of nanocomposites under the irradiation of NIR laser was induced via the interactions between dopamine groups of mPEG-g-PDAEAIM and Fe3O4 superparamagnetic nanoparticles to trigger the drug release. NMR, FT-IR, TEM, hysteresis loop analysis and MRI were utilized to characterize the materials. The DOX loaded nanocomposites exhibited pH-responsive and NIR dependent on/off switchable release profiles. The nanocomposites without drug loading (Fe3O4@mPEG-g-PDAEAIM) showed excellent biocompatibility while DOX loaded nanocomposites caused MCF-7 cells’ apoptosis due to the photothermal/chemotherapy combination effects. Overall, the pH and near-infrared dual responsive magnetic nanocomposite had a great potential for cancer therapy.

Novel temperature and pH dual-sensitive PNIPAM/CMCS/MWCNT semi-IPN nanohybrid hydrogels: Synthesis, characterization, and DOX drug release

ABSTRACTNovel poly(N-isopropylacrylamide)/carboxymethyl chitosan/multiwalled carbon nanotube semi-interpenetrating nanohybrid hydrogels were prepared, and the chemical structure and morphology were characterized. The prepared hydrogels showed temperature and pH dual-responsiveness, and the one containing multiwalled carbon nanotubes (MWCNTs)–COOH possessed high maximal swelling ratios. The phase transition produced at pH of 6.8–7.4 and temperature of 35–40°C, hinging on the system compositions and charge ratios. The hydrogels were used to load hydrophilic anticancer drug, with high entrapped efficiency of about 44%. The drug release changed with temperature, pH, and MWCNTs–COOH contents. The designed hydrogels can be used for site-specific target delivery of protein or hydrophilic anticancer drug.

Biocompatible Reduction and pH Dual-Responsive Core Cross-Linked Micelles Based on Multifunctional Amphiphilic Linear-Hyperbranched Copolymer for Controlled Anticancer Drug Delivery.

Novel strategy has been developed for fabricating the biocompatible reduction and pH dual-responsive core cross-linked (CCL) micelles as drug delivery system (DDS) for the controlled anticancer drug delivery, via the atom transfer radical polymerization (ATRP) of tert-butyl acrylate (tBA) with N,N'-bis(acryloyl)cystamine (BACy) as cross-linker and a multifunctional amphiphilic linear-hyperbranched copolymer as macroinitiator, which was synthesized via the self-condensing vinyl copolymerization (SCVCP) of tBA and p-chloromethylstyrene (CMS) with a poly(ethylene glycol) (PEG) based initiator (mPEG-Br). The hydrolyzed core cross-linked (HCCL) micelles were obtained as DDS for doxorubicin (DOX) by hydrolysis the tBA units into acrylic acid (AA) ones. The in vitro release performance showed that higher GSH concentration and/or lower pH value would lead to a faster and more efficient DOX release, meaning their reduction and pH dual-responsiveness. Therefore, the proposed HCCL micelles are expected to be potential anticancer drug-carriers for tumor microenvironment responsive controlled delivery.

Poly(N-isopropylacrylamide)-coated β-cyclodextrin–capped magnetic mesoporous silica nanoparticles exhibiting thermal and pH dual response for triggered anticancer drug delivery

ABSTRACTIn this research a novel controlled anticancer drug delivery system with dual pH and thermal responses was designed based on magnetic mesoporous silica nanoparticles that were anchored by β-cyclodextrin and coated by poly(N-isopropylacrylamide) (PNIPAM). Results demonstrated that the behavior of doxorubicin (anticancer drug) release depended on pH and temperature conditions. At endosomal pH (pH 5.5) the amount of drug release enhanced because the cap was removed from the pores. Furthermore, PNIPAM shell collapsed above the lower critical solution temperature and the releasing of drug increased. Thus, this nanocarrier would have the potential to be applied in the tumor therapy.

Core cross-linked poly(ethylene glycol)-graft-Dextran nanoparticles for reduction and pH dual responsive intracellular drug delivery

A kind of core cross-linked poly(ethylene glycol)-graft-Dextran nanoparticles (CPD NPs) was prepared by a simple chemical cross-linking method for reduction and pH dual response drug delivery. The resultant CPD NPs are of homogeneous spherical structure with sizes from 69±11 to 107±18nm. Doxorubicin (DOX) was then loaded into the CPD NPs in high efficiency, and showing typical reduction and pH dual responsive release profiles. The flow cytometric analysis and confocal laser scanning microscopy (CLSM) confirmed that the DOX-loaded CPD NPs could be internalized into cancer cell efficiently and release DOX in intracellular environment. Furthermore, cell cytotoxicity assays indicated that the CPD NPs had good biocompatibility toward both cancerous and normal cells, while the Dox-loaded CPD NPs exhibited significant inhibition of cell proliferation in various cancer cells. Therefore, this biocompatible CPD NP may have great potential for intracellular drug delivery in clinical cancer therapy.

Smart flocculant with temperature and pH response derived from starch

Smart flocculant derived from starch with temperature and pH dual response was prepared which can be easily regenerated and separated from contaminating dye solution by triggering the temperature and pH.

Amino-functionalized poly(N-vinylcaprolactam) derived from lysine: a sustainable polymer with thermo and pH dual stimuli response

Lysine, a renewable feedstock with economic feasibility, was tactfully cyclized to its corresponding cyclic lysine and then subjected to a reaction with acetylenes to yield a sustainable N-vinylcaprolactam (VCL) derivative. Well-defined PVCL with pendent amino groups was prepared via MADIX/RAFT polymerization.

Synthesis and Self-Assembly of o -Nitrobenzyl-Based Amphiphilic Hybrid Polymer with Light and pH Dual Response

In this paper, novel light-responsive polyhedral oligomeric silsesquioxane (POSS) end-capped poly(o-nitrobenzyl methacrylate) (POSS–PNBMA) are synthesized by the combination of atom transfer radical polymerization (ATRP) and click chemistry. After subsequent partial photocleavage of PNBMA yielding poly(methacrylic acid) (PMAA), pH- and light-responsive random copolymer of POSS–P(NBMA-co-MAA) is obtained. The o-nitrobenzyl-based amphiphilic hybrid polymer can self-assemble into spherical micelles in aqueous solution. Hydrophobic POSS and PNBMA segments aggregate into the inner core, and the hydrophilic PMAA chains tend to stretch from the core. The micellar morphology can be tuned by pH changes and UV irradiation. Light irradiation leads to the transformation of P(NBMA-co-MAA) into PMAA and to the reorganization of the assemblies, causing the release of encapsulated guest molecule Nile Red into water. This dual-responsive polymer has a broad potential use in targeted drug delivery.

Construction of a pillar[5]arene-based linear supramolecular polymer and a photo-responsive supramolecular network

A linear supramolecular polymer has been constructed from self-assembly of two complementary homoditopic monomers, an azobenzene-bridged pillar[5]arene dimer and a bisammonium salt, at high concentration based on the pillar[5]arene/secondary ammonium salt molecular recognition motif. This supramolecular polymer exhibited photo and pH dual-responsiveness. Polymer–oligomer and polymer–monomer transitions were reversibly regulated by UV/vis light irradiation and changing the solution pH, respectively. Furthermore, a photo-responsive supramolecular crosslinked liquid-crystalline polymer network based on the host–guest interactions between the azobenzene-bridged pillar[5]arene dimer and a secondary ammonium salt-functionalized poly(methyl acrylate) was fabricated.

Multifunctional hybrid silica nanoparticles for controlled doxorubicin loading and release with thermal and pH dual response

Controlled drug loading and release into tumor cells to increase the intracellular drug concentration is a major challenge for cancer therapy due to resistance and inefficient cellular uptake. Here a temperature and pH dually responsive PNiPAM/AA@SiO2 core-shell particles with internal controlled release were designed and fabricated for efficient cancer treatment, which could recognize the intrinsic pH differences between cancers and normal tissues. Upon lowering the temperature, doxorubicin was loaded into the PNiPAM/AA@SiO2 nanoparticles, whereas by increasing the acidity, previously loaded doxorubicin was quickly released. Comparing with common mesoporous silica particles (MSNs), this core-shell particle has more uniform size and better dispersity. In addition, dried PNiPAM/AA@SiO2 nanoparticles could be easily redispersed in distilled water. The in vitro cell culture experiments showed that not only PNiPAM/AA@SiO2 particles were more biocompatible and lower cytotoxic than MSN, but also DOX@PNiPAM/AA@SiO2 had higher drug releasing efficiency in the lysosomes and stronger inhibitory effect on tumor cell growth than DOX@MSN. All these features indicated that PNiPAM/AA@SiO2 particles have great potential in therapy applications.