Search

Glutathione (GSH) consumption-enhanced cancer therapies represent important potential cancer treatment strategies. Herein, we developed a new multifunctional diselenide-crosslinked hydrogel with glutathione peroxidase (GPx)-like catalytic activity for GSH depletion-enhanced glucose oxidase (GOx)-mediated tumor starvation and hypoxia-activated chemotherapy. By increasing acid and H 2 O 2 during GOx-induced tumor starvation, the degradation of the multiresponsive scaffold could be promoted, which led to accelerated release of the loaded drugs. Meanwhile, the overproduced H 2 O 2 led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H 2 O 2 and subsequent multimodal cancer treatment. Following the GOx-induced amplification of hypoxia, tirapazamine (TPZ) was transformed into the highly toxic benzotriazinyl radical (BTZ·), exhibiting enhanced antitumor activity. This GSH depletion-augmented cancer treatment strategy effectively boosted GOx-mediated tumor starvation and activated the hypoxia drug, leading to significantly enhanced local anticancer efficacy. There has been a growing interest in depleting intracellular GSH as a potential strategy for improving ROS-based cancer therapy. Herein, a bioresponsive diselenide-functionalized dextran-based hydrogel with GPx-like catalytic activity was developed for GSH consumption-enhanced local starvation- and hypoxia-activated melanoma therapy. Results showed that the overproduced H 2 O 2 led to accelerated intracellular GSH consumption under the cascade catalysis of small molecular selenides released from the degraded hydrogel, further enhancing the curative effect of in situ H 2 O 2 and subsequent multimodal cancer treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, fabrication of smart polymer and cotton fabrics with temperature- and pH-responsive as well as antibacterial activity was aimed. For this aim, random poly(N-isopropylacrylamide-comethacrylamide) P(NIPAM-co-MAM) copolymers containing different ratio of NIPAM/MAM monomers were synthesized through free radical addition polymerization method via 2,2'-azobis (2 methylpropionamide) dihydrochloride as an initiator. Analysis results showed that the copolymers were synthesized successfully and their LCST values were in the range of 33°C to 41°C. A selected sample of the synthesized copolymers was applied to the cotton fabric via double-bath impregnation method and thermo-responsive wetting property of the fabric was examined via wetting time and water uptake tests, contact angle measurement. The test results indicated that hydrophilic character of the fabric changed to the hydrophobic character reversibly depending on change in temperature. Besides, the fabric exhibited pH-responsive water absorption ability. The fabric could manage water vapor permeability via changing its pore size as well as hydrophilic character depending on temperature. Besides, it was concluded that the fabric had strong antibacterial activity against S.aureus bacteria. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract This study shows how highly branched poly(N -isopropyl acrylamide) (HB-PNIPAM) with a chain pendant solvatochromic dye (Nile red) could provide a fluorescence signal, as end groups bind to bacteria and chain segments become desolvated, indicating the presence of bacteria. Vancomycin was attached to chain ends of HB-PNIPAM or as pendant groups on linear polymers each containing Nile red. Location of the dye was varied between placement in the core of the branched polymer coil or the outer domains. Both calorimetric and fluorescence data showed that branched polymers responded to binding of both the peptide target (D-Ala-D-Aa) and bacteria in a different manner than analogous linear polymers; binding and response was more extensive in the branched variant. The fluorescence data showed that only segments located in the outer domains of branched polymers responded to binding of Gram-positive bacteria with little response when linear analogous polymer or branched polymer with the dye in the inner core was exposed to Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Excessive fouling and wetting phenomenon during long term membrane distillation (MD) cause membrane degradation and lead to consistent need for membrane replacement. Hence, effective cleaning of fouled membrane is imperative to recover its performance without compromising structural integrity. In this work, poly(N-isopropylacrylamide) (PNIPAM) hydrogel was coated on the hydrophobic PTFE support via spray coating (SC) method to fabricate membrane with switchable wettability for membrane cleaning. By using bovine serum albumin (BSA) and sodium alginate (SA) as model foulants, the antifouling property of hydrogel coated membrane (HCM) was evaluated. Furthermore, chemical-less thermal cleaning on the fouled HCM membrane using water at different temperature was tested to determine its water flux recovery. The interchanging hydrophilic/hydrophobic properties of PNIPAM around its LCST facilitated the foulants removal. It was found that the PNIPAM layer could fully coat the membrane and the flux of HCM performance can be recovered by up to 59.58% and 73.66% after subjecting to fouling by bovine serum albumin (BSA) and sodium alginate (SA). Surface free energy study also showed that hydrogel incorporation could ease the removal of BSA and SA upon water cleaning and does not contribute to wetting phenomenon. [Display omitted] • Spray coating of preheated hydrogels on PTFE membrane for thermoresponsive properties. • Thermal actuation of hydrogels allows higher flux recovery of BSA/SA fouled membrane. • Fouling and cleaning tendencies evaluated via surface free energy changes. • No wetting phenomenon of HCM evaluated via temperature polarization coefficient. [ABSTRACT FROM AUTHOR]

Spurred by significant progress in materials chemistry and drug delivery, charge-reversal nanocarriers are being developed to deliver anticancer formulations in spatial-, temporal- and dosage-controlled approaches. Charge-reversal nanoparticles can release their drug payload in response to specific stimuli that alter the charge on their surface. They can elude clearance from the circulation and be activated by protonation, enzymatic cleavage, or a molecular conformational change. In this review, we discuss the physiological basis for, and recent advances in the design of charge-reversal nanoparticles that are able to control drug biodistribution in response to specific stimuli, endogenous factors (changes in pH, redox gradients, or enzyme concentration) or exogenous factors (light or thermos-stimulation). [ABSTRACT FROM AUTHOR]