Durhamswanson5410

The efficient triggering of prodrug release has become a challengeable task for stimuli-responsive nanomedicine utilized in cancer therapy due to the subtle differences between normal and tumor tissues and heterogeneity. In this work, a dual ROS-responsive nanocarriers with the ability to self-regulate the ROS level was constructed, which could gradually respond to the endogenous ROS to achieve effective, hierarchical and specific drug release in cancer cells. In brief, DOX was conjugated with MSNs via thioketal bonds and loaded with β-Lapachone. TPP modified chitosan was then coated to fabricate nanocarriers for mitochondria-specific delivery. The resultant nanocarriers respond to the endogenous ROS and release Lap specifically in cancer cells. Subsequently, the released Lap self-regulated the ROS level, resulting in the specific DOX release and mitochondrial damage in situ, enhancing synergistic oxidation-chemotherapy. The tumor inhibition Ratio was achieved to 78.49%. The multi-functional platform provides a novel remote drug delivery system in vivo.

To prepare new polycationic pullulan derivatives exhibiting highly mucoadhesive and sustained drug release properties.

Hydroxy groups of pullulan were activated with mesyl chloride followed by conjugation with low-molecular weight polyamines. Pullulan-tris(2-aminoethyl)amine (Pul-TAEA) and pullulan-polyethyleneimine (Pul-PEI) were evaluated regarding swelling behaviour, mucoadhesive properties and potential to control drug release.

Pul-TAEA and Pul-PEI exhibited excellent swelling properties at pH6.8 showing 240- and 370-fold increase in weight. Compared to unmodified pullulan, Pul-TAEA and Pul-PEI displayed 5- and 13.3-fold increased dynamic viscosity in mucus. Mucoadhesion studies of Pul-TAEA and Pul-PEI on intestinal mucosa showed a 6- and 37.8-fold increase in tensile strength, and a 72- and 120-fold increase in mucoadhesion time compared to unmodified pullulan, respectively. Due to additional ionic interactions between cationic groups on polyaminated pullulans and an anionic model drug, a sustained drug release was achieved.

Polyaminated pullulans are promising novel mucoadhesive excipients for mucosal drug delivery.

Polyaminated pullulans are promising novel mucoadhesive excipients for mucosal drug delivery.Immobilizing metal oxide nanoparticles onto polymer substrate could endow antibacterial performance and enhance mechanical property. In-situ strategy is extensively used to better control loading percentage, uniform distribution and particle size of nanoparticles. However, it still remains challenge in depositing stable bicomponents copper oxide nanoparticles on non-adhesive surface of cellulose hydrogel in high density. In this study, Cu2O@CuO nanospheres were in-situ deposited onto cellulose hydrogels via liquid phase reduction. Particularly, sodium hydroxide in the cellulose hydrogel severed as the precipitant, which not only save the usage of chemicals, but also enhanced binding between nanoparticles and the hydrogel. Furthermore, Cu2O@CuO nanospheres demonstrate biocidal antifouling performance against Escherichia coli by releasing biocide. After hydrolysis of precipitation layer, the exposed cellulose hydrogel exhibits fouling-resistant property for Chlorella Vulgaris due to the hydration layer on its surface. Such composites hold great promise in antifouling coatings and other applications.Development of versatile medical dressing with good immediate and long-lasting antibacterial, hygroscopic and moisturizing abilities is of great significance for management of chronic wounds. Cotton gauze (CG) can protect wounds and promote scabbing, but can cause wound dehydration and loss of biologically active substances, thereby greatly delays wound healing. Herein, a bi-functional CG dressing (CPCG) was developed by chemically grafting polyhexamethylene guanidine (PHMG) and physically adsorbing chitosan (CS) onto the CG surface. Due to the powerful microbicidal activity of PHMG, CPCG exhibited excellent immediate and long-lasting antibacterial activity against gram-positive and gram-negative bacteria. Moreover, the abundant hydroxyl and amino groups in CS endowed CPCG with good biocompatibility, moisture absorption, moisturizing and cell scratch healing performances. Importantly, CPCG can be easily fabricated into a bandage to conveniently manage infected full-skin wounds. Together, this study suggests that CPCG is a versatile wound dressing, having enormous application potential for management chronic wounds.Chitosan, cellulose nanocrystals, and halloysite nanotubes in the presence of calcium cations were used to fabricate a three-dimensional nanocomposite scaffold. The FTIR and XRD analyses revealed that formation of the network and incorporation of halloysite nanotubes into it were successful. FESEM images showed that the addition of higher amounts of halloysite nanotubes into the scaffold's matrix leads to more and smaller pores. The addition of halloysite nanotubes enhanced the thermal stability, mechanical characteristics, water uptake, and degradation rate of the nanocomposite scaffold. The nanocomposite scaffold represented good biomineralization, great cell proliferation, and acceptable cell attachment. Furthermore, the capability of the nanocomposite scaffold for curcumin delivery was approved through cell proliferation, cumulative release, and antibacterial studies. Cell proliferation of the nanocomposite with 10 wt% curcumin-loaded halloysite nanotubes reached around 175% after 72 h. Considering the results, the prepared nanocomposite scaffold holds great potential for being used in bone tissue engineering applications.An innovative approach was developed to engineer a multi-layered chitosan scaffold for osteochondral defect repair. A combination of freeze drying and porogen-leaching out methods produced a porous, bioresorbable scaffold with a distinct gradient of pore size (mean = 160-275 μm). Incorporation of 70 wt% nano-hydroxyapatite (nHA) provided additional strength to the bone-like layer. The scaffold showed instantaneous mechanical recovery under compressive loading and did not delaminate under tensile loading. The scaffold supported the attachment and proliferation of human mesenchymal stem cells (MSCs), with typical adherent cell morphology found on the bone layer compared to a rounded cell morphology on the chondrogenic layer. Osteogenic and chondrogenic differentiation of MSCs preferentially occurred in selected layers of the scaffold in vitro, driven by the distinct pore gradient and material composition. This scaffold is a suitable candidate for minimally invasive arthroscopic delivery in the clinic with potential to regenerate damaged cartilage and bone.The unparalleled dependency on petroleum based sources urged the research community to focus on developing renewable products, among which nanocellulose based commodities stands at the zenith due to its abundance, biodegradability and biocompatibility. Nanocellulose in form of coatings, aerogels, hydrogels, films and membranes have its own space in the research platform. Selleckchem Bromopyruvic The different coating technologies like spray, bar, roller, dip and foam coating are currently employed for the fabrication. The profound surface hydroxyl groups on the cellulose helps to incorporate desired properties like antimicrobial or antioxidant activities, barrier properties, superhydrophobicity or superhydrophilicity as per the applications ranging from biomedical to material engineering. Yet, the chemistry of these coatings have to be precisely tuned for its commercialization since many factors play challenging roles while the fabrication process like adhesion, brittleness and barrier properties. The manuscript discusses these aspects of the nanocellulose based coatings along with its challenges and future perspectives.Intelligent controlled release systems (ICRS) displayed great achievement in agriculture by enhancing the utilization efficiency of agrochemicals. In this work, an intelligent graft copolymer (Alg-g-P(NIPAm-co-NDEAm)) with alginate (Alg) backbone and thermo-responsive poly(N-isopropyl acrylamide-co-N,N-diethylacrylamide) (P(NIPAm-co-NDEAm)) side chain was constructed as the matrix of ICRS through redox copolymerization, and its thermo-induced responsive property was studied. Then, the copolymer was mixed with a promising photothermal material semi-coke (SC) to form hydrogel beads (Ca-Alg-g-P(NIPAm-co-NDEAm)/SC) by ion crosslinking. The water absorbency of beads under different stimuli (pH, temperature, and light) presented outstanding responsive performance and the swelling mechanism was analyzed through coupling theory. Furthermore, the release of glyphosate (Gly) from Ca-Alg-g-P(NIPAm-co-NDEAm)/SC under environmental stimuli displayed regulatable behaviors. This multi-responsive hydrogel bead shows bright prospect in the sustainable advancement of crop production.In this study, a biodegradable photodynamic antibacterial film (Car-Cur) was prepared using casting method with κ-Carrageenan (κ-Car) as film-forming substrate and curcumin-β-cyclodextrin (Cur-β-CD) complex as photosensitizer. The comprehensive performance of this Car-Cur film was investigated. The obtained results showed that the concentration of Cur-β-CD was an important factor determining the properties of film including tensile strength (TS) elongation at break (EB), water vapor permeability (WVP), water content (WC) and thermal stability. When the concentration of Cur-β-CD is 1%, the film demonstrated the maximum TS and EB, increased thermal stability, with desirable WVP and WC. Furthermore, this film also showed good photodynamic antibacterial potential against Staphylococcus aureus and Escherichia coli upon irradiation of blue LED light. Moreover, the film can be degraded in the soil in one week. In conclusion, our results suggested Car-Cur photodynamic film could be developed as biodegradable antimicrobial packaging material for food preservation.Novel bio-based nanocomposites were developed as carriers for loading and sustained-release of vanillin (Van.) and cinnamaldehyde (Cinn.) antioxidants. The composites were obtained by intercalation of chitosan (CS) into sodium montmorillonite (CS/Mt), incorporation of chitosan with polyaniline (CS/PANI) and chitosan/polyaniline/exfoliated montmorillonite (CS/PANI/Mt). The structure and morphology of composites were characterized by FTIR, XRD, SEM and TEM. The release data of Van. and Cinn. from CS and CS/Mt obeyed well zero-order equation. However, Higuchi and Korsmeyer-Peppas models fitted well the release data from CS/PANI and CS/Mt composites. Their antifungal activity was examined towards Fusarium oxysporum and Pythium debaryanum. In vitro assay, CS, Cinn., Van., CS/PANI and CS/PANI/Cinn., have a strong inhibitory effect on the linear growth of the target pathogens, even at lower concentrations. Greenhouse assay indicated that seedling treatment by the loaded CS/PANI/Cinn and CS/Mt/Cinn. reduced both disease index and disease incidence parameters of both pathogens and possessed seedlings growth promoting potential of tomato compared to untreated-infected controls.New quaternized chitosan derivatives HT-TMC were synthesized as a result of copper catalyzed azide-alkyne [3 + 2] cycloaddition (CuAAC). The structure of the HT-TMC was verified by 2D NMR. The synthesis was carried out as a result of the formation of Cu(I) in situ, under the action of ultrasound in aerobic conditions in the presence of acetic acid and metallic copper (copper turnings). The new derivatives were characterized by increased pH range of solubility (DS range 18-76%) and the presence of antibacterial and fungicidal activities. The proposed catalytic system makes it possible to easily and efficiently obtain new derivatives of chitosan as a result of ultrasound-promoted CuAAC.