Biodegradable composites from poly(butylene adipate-co-terephthalate) with carbon nanoparticles: Preparation, characterization and performances

The development of composites for food packaging that have good mechanical and antimicrobial characteristics is still a major challenge. In applications like food packaging, the usage of poly (butylene adipate-co-terephthalate) (PBAT), which has an adversative effect on the environment and reduces petroleum resources, has grown widespread. The present work reveals PBAT composites reinforced with CNPs at a few percentages up to 5.0 wt %. The PBAT/CNPs composites were produced using the solvent casting method. The results of TGA studies, CNPs significantly enhanced the thermal stability of composites using PBAT. The mechanical strength of the PBAT composites was improved by increasing CNPs concentration. Tensile strength increased from 7.38 to 10.22 MPa, respectively. The oxygen transmission rate (OTR) decreased with increasing the CNPs concentrations. The barrier properties (H2O and O2) of PBAT were improved by the presence of CNPs. WVTR was calculated to be 108.6 ± 1.8 g/m2/day for PBAT. WVTR reduced when CNPs concentration in PBAT increased. The PCN-5.0 film sample had the lowest WVTR value, 34.1 ± 3.1 g/m2/day. For PCN-3.0, WVTR dropped by 45.39%, indicating and even with a 3.0 wt% loading of CNPs in PBAT, the rise is noticeable. Contact angle measurements indicate that PBAT/CNPs composites becomes hydrophobic after reinforcing. Gram-positive (S. aureus) and Gram-negative (E. coli) food-borne pathogenic microorganisms showed enhanced antimicrobial activity against the developed PBAT composites. The carrot pieces preserved their freshness for an extended period of 12 days while packaged in the PBAT/CNPs composite film, indicating that the film is an effective and excellent packaging for food materials.

Encapsulation of tannic acid in polyvinylidene fluoride mediated electrospun nanofibers and its antibiofilm and antibacterial activities

In the past 15 years or more, interest in polymer-mediated nanofibers (NFs), a significant class of nanomaterials, has grown. Although fibers with a diameter of less than 1 mm are frequently commonly referred to as NFs, and are typically defined as having a diameter of less than several hundreds of nanometers. Due to the increased antibiotic resistance of many diseases nowadays, NFs with antibacterial activity are quite important. A flexible technique for creating NFs with the desired characteristics is called electrospinning. This research article describes how to make electrospun NFs of tannic acid (TA) with polyvinylidene fluoride (PVDF) as the template. As a result, the absorbance of the obtained NFs has been raised without forming any additional peaks in the spectral ranges. The obtained NF has a gradual increase in intensity, and the FT-IR data show that the TA is present in the NFs. FE-SEM images show that the NFs are discovered to be completely bead-free. Since TA reduced the viscosity of the spinning solution while marginally increasing solution conductivity, PVDF NFs have a greater average fiber diameter (AFD) than NFs of TA with PVDF, which is likely a result of the TA solutions in it. The findings showed that TA greatly decreased S. aureus and E. coli's ability to attach. The acquired NFs created in this work may have significant potential for reducing the pathogenicity of S. aureus and E. coli as well as their ability to build biofilms.

Rapid Transformation in Wetting Properties of PTFE Membrane Using Plasma Treatment

In this paper, we describe the surface modification of polytetrafluoroethylene (PTFE) through the plasma treatment process. Several parameters including different active gases, RF power, distance between the plasma source and sample, and plasma duration were optimized to reduce the hydrophobic nature of PTFE. Three different active gases were used (i.e., N2, O2, and (Ar+H2)); N2 was effective to reduce the hydrophobicity of PTFE within a shorter plasma duration of 2 min. Several surface characterizations including ATR-FTIR, water contact angle, FE-SEM, and XPS were utilized to verify the neat and modified PTFE surface after plasma treatment. The plasma treatment using N2 as an active gas improved the wettability of the PTFE membrane, showing a water contact angle of 109.5° when compared with the neat PTFE (141.9°). The SEM images of plasma-treated PTFE showed greater modifications on the surface indicating non-uniform fiber alignment and torn fibers at several places. The obtained results confirm the fact that plasma treatment is an effective way to modify the PTFE surface without altering its bulk property.

Ex vivo fluorescence imaging for the identification of rhodamine-labeled bovine serum albumin and chitosan-coated gold and silver nanoparticles

Therapeutic potential and toxic effects of in vivo administered gold nanoparticles (GNPs) and silver nanoparticles (SNP) depend on distribution in tissues. Rhodamine (Rho) labeled bovine serum albumin (BSA) and chitosan (Chi) were prepared by covalent conjugation and were characterized by fluorescence spectral analysis. GNP and SNP were coated with the labeled conjugates of BSA and chitosan by adsorption. The soluble Rho-BSA or Rho-Chi conjugates, uncoated, and conjugate-coated GNP, and SNP were orally administered into 8-week-old rats. After 24 h, rats were euthanized and the liver, kidney, spleen, and thymus were dissected. The tissues were examined ex vivo using a small animal in vivo imaging system. The liver, kidney, and thymus displayed higher fluorescence due to increased accumulation of Rho-BSA or Rho-Chi conjugate-coated nanoparticles (NPs) in the tissues as compared to the spleen where lower fluorescence was noticed. Tissues obtained from rats that were administered Rho-BSA or Rho-Chi conjugate-coated GNP and SNP showed tenfold higher fluorescence intensity as compared to tissues from rats that were given soluble conjugates or NP alone. The results strongly suggest significant tissue distribution of NP following oral administration.

Enhancement of physicochemical characterization of nanocomposites on Ag+/Fe2+ codoped hydroxyapatite for antibacterial and anticancer properties

The synthesis of nanosized Ag+/Fe2+ codoped hydroxyapatite (HAp) nanocomposite materials with antibacterial and anticancer characteristics is highly attractive for advancing the development of biological applications. The objective of this study was to evaluate the antibacterial and anticancer characteristics of Ag+/Fe2+ codoped hydroxyapatite materials. We developed a facile chemical precipitation method for the fabrication of Ag+/Fe2+:HAp nanocomposites. The developed Ag+/Fe2+:HAp nanocomposite materials were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). For measuring the size of Ag+/Fe2+:HAp nanocomposites, dynamic light scattering (DLS) is an advantageous method. The chemical states and chemical composition of Ag+/Fe2+:HAp were observed by X-ray photoelectron spectroscopy (XPS) analysis. In addition, the antibacterial efficacy of Ag+/Fe2+:HAps against Gram-positive (S.aureus), and Gram-negative (S.typhi, and E.Coli) microorganisms is examined in this current study. Ag+/Fe2+:HAp nanocomposite materials have been evaluated for biological toxicity in vitro, and the results showed that the particles were excellent at identifying and killing cancer cells. In this respect, Ag+/Fe2+:HAp nanocomposites significantly impact human colon cancer cells (HT29) while have no effect on normal fibroblast cells (L929).

Enhanced Activity and Stability of Heteroatom-Doped Carbon/Bimetal Oxide for Efficient Water-Splitting Reaction

The research community is actively exploring ways to create cost-efficient and high-performing electrocatalysts for the oxygen evolution reaction. In this investigation, an innovative technique was employed to produce heteroatom-doped carbon containing NiCo oxides, i.e., HC/NiCo oxide@800, in the form of a three-dimensional hierarchical flower. This method involved the reduction of a bimetallic (Ni, Co) metal-organic framework, followed by carefully controlled oxidative calcination. The resulting porous flower-like structure possess numerous advantages, such as expansive specific surface areas, excellent conductivity, and multiple electrocatalytic active sites for both hydrogen and oxygen evolution reactions. Moreover, the presence of oxygen vacancies within HC/NiCo oxide@800 significantly enhances the conductivity of the NiCo substance, thus expediting the kinetics of both the processes. These benefits work together synergistically to enhance the electrocatalytic performance of HC/NiCo oxide@800. Empirical findings reveal that HC/NiCo oxide@800 electrocatalysts demonstrate exceptional catalytic activity, minimal overpotential, and remarkable stability when deployed for both hydrogen evolution and oxygen evolution reactions in alkaline environments. This investigation introduces a fresh avenue for creating porous composite electrocatalysts by transforming metal-organic frameworks with controllable structures. This approach holds promise for advancing electrochemical energy conversion devices by facilitating the development of efficient and customizable electrocatalytic materials.

Boosting Fenton's Oxidation Reaction by a Food Waste-Derived Catalyst for Oxidizing Organic Dyes: Synergistic Effect of Complex Iron Oxides and the Layer Carbon Structure

The constant increase in the human population drives the demand for food supply and thereby increasing the food wastage dramatically all over the world. Especially, around 60% of banana biomass has been generated as inedible domestic waste. Herein, we successfully employed banana waste as a catalyst for Fenton's oxidation reaction. The biomass-derived catalysts were subjected to various characterization techniques such as XRD, ATR-FTIR, confocal Raman spectroscopy, and XPS, XRF, BET, SEM, and TEM analyses. The XRD results revealed that, after carbonization of the dried banana bract material, a perloffite-like metal oxide phase was formed due to the aerial oxidation reaction. Characterization results of Raman and ATR-FTIR confirm that the carbonized catalyst possesses a layer-like structure with different types of functional groups. The calcium, magnesium, potassium, sodium, and iron are the dominating metal species in the resultant material, which was evident from the XRF and EDAX analyses. The carbonized banana bract catalyst is successfully utilized for the Fenton's oxidation reaction at neutral pH. The experimental results showed that the degradation efficiency of the fresh catalyst was 95% in 4 h of reaction time, and the stability of the catalyst was retained up to nine consecutive cycles. The high activity of MB, methylene blue, is mainly attributed to the strong interaction between oxy functional groups of the catalyst and MB molecule as compared to RhB. Further, the calculated efficiency of the hydrogen peroxide was found to be 99% and the self-decomposition of hydrogen peroxide by the formed metal oxides was highly limited.

Dramatic reduction of toxicity of Poly(hexamethylene guanidine) disinfectant by charge neutralization

The current study aimed to investigate the toxicity of positively charged polyhexamethylene guanidine (PHMG) polymer and its complexation with different anionic natural polymers such as k-carrageenan (kCG), chondroitin sulfate (CS), sodium alginate (Alg.Na), polystyrene sulfonate sodium (PSS.Na) and hydrolyzed pectin (HP). The physicochemical properties of the synthesized PHMG and its combination with anionic polyelectrolyte complexes (PECs) namely PHMG:PECs were characterized using zeta potential, XPS, FTIR, and TG analysis. Furthermore, cytotoxic behavior of the PHMG and PHMG:PECs, respectively, were evaluated using human liver cancer cell line (HepG2). The study results revealed that the PHMG alone had slightly higher cytotoxicity to the HepG2 cells than the prepared polyelectrolyte complexes such as PHMG:PECs. The PHMG:PECs showed a significant reduction of cytotoxicity to the HepG2 cells than the pristine PHMG alone. A reduction of PHMG toxicity was observed may be due to the facile formation of complexation between the positively charged PHMG and negatively charged anionic natural polymers such as kCG, CS, Alg. Na, PSS.Na and HP, respectively, via charge balance or neutralization. The experimental results indicate that the suggested method might significantly lower PHMG toxicity while improving biocompatibility.

Salbutamol Attenuates Diabetic Skeletal Muscle Atrophy by Reducing Oxidative Stress, Myostatin/GDF-8, and Pro-Inflammatory Cytokines in Rats

Type 2 diabetes is a metabolic disorder that leads to accelerated skeletal muscle atrophy. In this study, we aimed to evaluate the effect of salbutamol (SLB) on skeletal muscle atrophy in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic rats. Male Sprague Dawley rats were divided into four groups (n = 6): control, SLB, HFD/STZ, and HFD/STZ + SLB (6 mg/kg orally for four weeks). After the last dose of SLB, rats were assessed for muscle grip strength and muscle coordination (wire-hanging, rotarod, footprint, and actophotometer tests). Body composition was analyzed in live rats. After that, animals were sacrificed, and serum and gastrocnemius (GN) muscles were collected. Endpoints include myofibrillar protein content, muscle oxidative stress and antioxidants, serum pro-inflammatory cytokines (interleukin-1β, interleukin-2, and interleukin-6), serum muscle markers (myostatin, creatine kinase, and testosterone), histopathology, and muscle 1H NMR metabolomics. Findings showed that SLB treatment significantly improved muscle strength and muscle coordination, as well as increased lean muscle mass in diabetic rats. Increased pro-inflammatory cytokines and muscle markers (myostatin, creatine kinase) indicate muscle deterioration in diabetic rats, while SLB intervention restored the same. Also, Feret's diameter and cross-sectional area of GN muscle were increased by SLB treatment, indicating the amelioration in diabetic rat muscle. Results of muscle metabolomics exhibit that SLB treatment resulted in the restoration of perturbed metabolites, including histidine-to-tyrosine, phenylalanine-to-tyrosine, and glutamate-to-glutamine ratios and succinate, sarcosine, and 3-hydroxybutyrate (3HB) in diabetic rats. These metabolites showed a pertinent role in muscle inflammation and oxidative stress in diabetic rats. In conclusion, findings showed that salbutamol could be explored as an intervention in diabetic-associated skeletal muscle atrophy.

Image findings of anti-neutrophil cytoplasmic antibody-associated vasculitis involving the skull base

AIM

To investigate computed tomography (CT) and magnetic resonance imaging (MRI) features of skull bases involving anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV).

MATERIALS AND METHODS

A retrospective review was undertaken to identify an institutional historical cohort of 17 patients with confirmed AAV who underwent CT or MRI and had skull base involvement between 2002 and 2021. Two radiologists reviewed the extent and features of the lesions, bone changes, and other MRI findings.

RESULTS

A total of 17 patients (12 men; mean age ± standard deviation, 46.5 ± 17.1 years) were selected. AAV presented as infiltrative lesions with involvement at various sites. Most cases involved the paranasal sinuses (PNS; 88%, 15/17), nasopharynx (88%, 15/17), pterygopalatine fossa (82%, 14/17), and parapharyngeal space (82%, 14/17), frequently accompanied by mucosal irregularity of the PNS and nasopharynx (71%, 12/17). Central skull base and temporal bone involvement were seen in 53% (9/17) and 38% (6/16) of cases, respectively. On T1-weighted imaging (WI) and T2WI MRI, all lesions (15/15) showed predominant signal iso-intensity to grey matter.

CONCLUSIONS

Although radiological findings of AAV are non-specific and skull base involvement is less common, AAV may be considered if infiltrative lesions predominantly involving the PNS, nasopharynx, pterygopalatine fossa, and parapharyngeal space with combined bone changes of skull base are seen.

Facile Synthesis of Nitrogen-Rich Porous Carbon/NiMn Hybrids Using Efficient Water-Splitting Reaction

Proper design of multifunctional electrocatalyst that are abundantly available on earth, cost-effective and possess excellent activity and electrochemical stability towards oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are required for effective hydrogen generation from water-splitting reaction. In this context, the work herein reports the fabrication of nitrogen-rich porous carbon (NRPC) along with the inclusion of non-noble metal-based catalyst, adopting a simple and scalable methodology. NRPC containing nitrogen and oxygen atoms were synthesized from polybenzoxazine (Pbz) source, and non-noble metal(s) are inserted into the porous carbon surface using hydrothermal process. The structure formation and electrocatalytic activity of neat NRPC and monometallic and bimetallic inclusions (NRPC/Mn, NRPC/Ni and NRPC/NiMn) were analyzed using XRD, Raman, XPS, BET, SEM, TEM and electrochemical measurements. The formation of hierarchical 3D flower-like morphology for NRPC/NiMn was observed in SEM and TEM analyses. Especially, NRPC/NiMn proves to be an efficient electrocatalyst providing an overpotential of 370 mV towards OER and an overpotential of 136 mV towards HER. Moreover, it also shows a lowest Tafel slope of 64 mV dec^-1 and exhibits excellent electrochemical stability up to 20 h. The synergistic effect produced by NRPC and bimetallic compounds increases the number of active sites at the electrode/electrolyte interface and thus speeds up the OER process.

Investigating the Inhibitory Properties of Cupressus sempervirens Extract against Copper Corrosion in 0.5 M H2SO4: Combining Quantum (Density Functional Theory Calculation-Monte Carlo Simulation) and Electrochemical-Surface Studies

The study investigates the potential of Cupressus sempervirens (EO) as a sustainable and eco-friendly inhibitor of copper corrosion in a 0.5 M sulfuric acid medium. The electrochemical impedance spectroscopy analysis shows that the effectiveness of corrosion inhibition rises with increasing inhibitor concentrations, reaching 94% with the application of 2 g/L of EO, and potentiodynamic polarization (PDP) studies reveal that EO functions as a mixed-type corrosion inhibitor. In addition, the Langmuir adsorption isotherm is an effective descriptor of its adsorption. Scanning electron microscopy/energy-dispersive X-ray spectroscopy, atomic force microscopy surface examination, and contact angle measurement indicate that EO may form a barrier layer on the metal surface. Density functional theory calculations, Monte Carlo simulation models, and the radial distribution function were also used to provide a more detailed understanding of the corrosion protection mechanism. Overall, the findings suggest that Cupressus sempervirens (EO) has the potential to serve as an effective and sustainable corrosion inhibitor for copper in a sulfuric acid medium, contributing to the development of green corrosion inhibitors for environmentally friendly industrial processes.

The effect of chelators on additives in the surface characterization and electrochemical properties of an eco-friendly electroless copper nano deposition

We represent the results of a study on as the chelators used in the environmentally friendly electroless deposition bath changed depending on the amounts of hydroxides were present. The baths were prepared using polyhydroxides, glycerol and sorbitol, as chelators with copper methanesulfonate as the metal ion. Dimethylamine borane (DMAB) was used as the reducing agent with N-methylthiourea and cytosine, as additives in both the glycerol and sorbitol contained baths. Potassium hydroxide was used as the pH adjuster, with glycerol and sorbitol baths maintained at a pH of 11.50 and 10.75 respectively at a room temperature of 28 ± 2 °C. XRD, SEM, AFM, cyclic voltammetry studies, Tafel and Impedance studies, as well as additional methods, were employed to monitor and record the surface, structural, and electrochemical characteristics of the deposits and bath. The reports of the study gave interesting results, which clearly the effect of chelators on additives in the nano deposition of copper in an electroless deposition bath.

Dual pH- and Thermo-Sensitive Poly(N-isopropylacrylamide-co-allylamine) Nanogels for Curcumin Delivery: Swelling-Deswelling Behavior and Phase Transition Mechanism

Curcumin (Cur) is a beneficial ingredient with numerous bioactivities. However, due to its low solubility and poor bioavailability, its therapeutic application is limited. In this work, we prepared poly-N-isopropylacrylamide p(NIPAm) and polyallylamine p(Am)-based nanogel (p(NIPAm-co-Am)) NG for a dual pH- and temperature-sensitive copolymer system for drug delivery application. In this copolymer system, the p(NIPAm) segment was incorporated to introduce thermoresponsive behavior and the p(Am) segment was incorporated to introduce drug binding sites (amine groups) in the resulting (p(NIPAm-co-Am)) NG system. Various instrumental characterizations including ¹H nuclear magnetic resonance (¹H NMR) spectroscopy, Fourier transform infrared (FT-IR) analysis, scanning electron microscopy (SEM), zeta potential, and particle size analysis were performed to confirm the copolymer synthesis. Curcumin (Cur), an anticancer bioactive substance, was employed to assess the in vitro drug loading and release performance of the resulting copolymer nanogels system at varied pH levels (pH 7.2, 6.5, and 4.0) and temperatures (25 °C, 37 °C, and 42 °C). The cytocompatibility of the p(NIPAm-co-Am) NG sample was also tested on MDA-MB-231 cells at various sample concentrations. All the study results indicate that the p(NIPAm-co-Am) NG produced might be effective for drug loading and release under pH and temperature dual-stimuli conditions. As a result, the p(NIPAm-co-Am) NG system has the potential to be beneficial in the use of drug delivery applications in cancer therapy.

k-Carrageenan based magnetic@polyelectrolyte complex composite hydrogel for pH and temperature-responsive curcumin delivery

The dual stimuli-responsive drug delivery system has attracted a lot of interest in controlled drug delivery to specific sites. The magnetic iron oxide nanoparticles integrated polyelectrolyte complex-based hydrogel (MPEC HG) system was developed in this work. First, magnetic nanoparticles were produced in situ in the synthetic polymer polyhexamethylene guanidine (PHMG). Furthermore, the natural biopolymer k-carrageenan (kCG) was employed to form the polyelectrolyte complex (PEC) through charge-balancing interaction between positively charged guanidine units and negatively charged sulfonate groups. Various characterization approaches were used to characterize the developed magnetic polyelectrolyte complex hydrogel (MPEC HG) system. Curcumin (Cur) was employed as a model bioactive agent to examine the drug loading and stimuli-responsive drug release efficiency of the MPEC HG system. Under the combined pH and temperature stimuli conditions (pH 5.0/42 °C), the developed hydrogel system demonstrated great drug loading efficiency (~ 68 %) and enhanced drug release. Furthermore, the MPEC HG system's in vitro cytotoxicity behavior was investigated on a human liver cancer (HepG2) cell line, and the results revealed that the MPEC HG system is biocompatible. As a result, the MPEC HG system might be used for dual pH and temperature stimuli-responsive drug delivery applications in cancer therapy.

L-lysine Functionalized Mesoporous Silica Hybrid Nanoparticles for pH-Responsive Delivery of Curcumin

Stimuli-responsive controlled drug delivery systems have attracted the attention of researchers in recent decades due to their potential application in developing efficient drug carriers that are responsive to applied stimuli triggers. In this work, we present the synthesis of L-lysine (an amino acid that combines both amine and carboxylic acid groups in a single unit) modified mesoporous silica nanoparticles (MS@Lys NPs) for the delivery of the anticancer bioactive agent (curcumin, Cur) to cancer cells. To begin, mesoporous silica hybrid nanoparticles (MS@GPTS NPs) with 3-glycidoxypropyl trimethoxy silane (GPTS) were synthesized. The L-lysine groups were then functionalized onto the mesopore channel surfaces of the MS@GPTS NPs through a ring-opening reaction between the epoxy groups of the GPTS and the amine groups of the L-lysine units. Several instrumental techniques were used to examine the structural properties of the prepared L-lysine-modified mesoporous silica nanoparticles (MS@Lys NPs). The drug loading and pH-responsive drug delivery behavior of MS@Lys NPs were studied at different pH levels (pH 7.4, 6.5, and 4.0) using curcumin (Cur) as a model anticancer bioactive agent. The MS@Lys NPs' in vitro cytocompatibility and cell uptake behavior were also examined using MDA-MB-231 cells. The experimental results imply that MS@Lys NPs might be used in cancer therapy as pH-responsive drug delivery applications.

Selective removal of copper (II) ions from aqueous solution using pyridyl-bridged mesoporous organosilica hybrid adsorbent

The incorporation of active functional groups into the mesoporous organosilica hybrid materials is efficient for various applications. A newly designed mesoporous organosilica adsorbent was prepared using diaminopyridyl groups bridged-(bis-trimethoxy)organosilane (DAPy) precursor by using Pluronic P123 as structure directing template via sol-gel co-condensation method. The hydrolysis reaction of DAPy precursor and tetraethyl orthosilacate (TEOS) with a DAPy content of about 20 mol% to TEOS were incorporated into the mesopore walls of the mesoporous organosilica hybrid nanoparticles (DAPy@MSA NPs). Low-angle XRD and FT-IR, N₂ adsorption-desorption analysis, SEM, TEM, and TG analysis were used to characterize the synthesized DAPy@MSA NPs. The DAPy@MSA NPs exhibit an order mesoporous structure with a high surface area, mesopore size and pore volume of approximately ∼465 m²/g, 4.4 nm and 0.48 cm³/g, respectively. The pyridyl groups integrated DAPy@MSA NPs showed the selective adsorption of Cu²⁺ ions from the aqueous medium by metal-ligand complex coordination of Cu²⁺ ions with the integrated pyridyl groups and the pendant hydroxyl (-OH) functional groups present into the mesopore walls of the DAPy@MSA NPs. In the presence of other competitive metal ions (Cr²⁺, Cd²⁺, Ni²⁺, Zn²⁺, and Fe²⁺), the DAPy@MSA NPs showed relatively high adsorption of Cu²⁺ ions (276 mg/g) from aqueous solution as compared to the other competitive metal ions at the same concentration (100 mg/L) of initial metal ion solution.

Atenolol Ameliorates Skeletal Muscle Atrophy and Oxidative Stress Induced by Cast Immobilization in Rats

(1) Background: Skeletal muscle atrophy is a common and debilitating condition associated with disease, bed rest, and inactivity. We aimed to investigate the effect of atenolol (ATN) on cast immobilization (IM)-induced skeletal muscle loss. (2) Methods: Eighteen male albino Wistar rats were divided into three groups: a control group, an IM group (14 days), and an IM+ATN group (10 mg/kg, orally for 14 days). After the last dose of atenolol, forced swimming test, rotarod test, and footprint analysis were performed, and skeletal muscle loss was determined. Animals were then sacrificed. Serum and gastrocnemius (GN) muscles were then collected, serum creatinine, GN muscle antioxidant, and oxidative stress levels were determined, and histopathology and ¹H NMR profiling of serum metabolites were performed. (3) Results: Atenolol significantly prevented immobilization-induced changes in creatinine, antioxidant, and oxidative stress levels. Furthermore, GN muscle histology results showed that atenolol significantly increased cross-sectional muscle area and Feret's diameter. Metabolomics profiling showed that glutamine-to-glucose ratio and pyruvate, succinate, valine, citrate, leucine, isoleucine, phenylalanine, acetone, serine, and 3-hydroxybutyrate levels were significantly higher, that alanine and proline levels were significantly lower in the IM group than in the control group, and that atenolol administration suppressed these metabolite changes. (4) Conclusions: Atenolol reduced immobilization-induced skeletal muscle wasting and might protect against the deleterious effects of prolonged bed rest.

L-Lysine-Modified pNIPAm-co-GMA Copolymer Hydrogel for pH- and Temperature-Responsive Drug Delivery and Fluorescence Imaging Applications

The development of dual-stimuli-responsive hydrogels attracts much research interest owing to its unique stimuli-responsive characteristics. In this study, a poly-N-isopropyl acrylamide-co-glycidyl methacrylate-based copolymer was synthesized by incorporating N-isopropyl acrylamide (NIPAm) and a glycidyl methacrylate (GMA) monomer. The synthesized copolymer, pNIPAm-co-GMA was further modified with L-lysine (Lys) functional units and further conjugated with fluorescent isothiocyanate (FITC) to produce a fluorescent copolymer pNIPAAm-co-GMA-Lys hydrogel (HG). The in vitro drug loading and dual pH- and temperature-stimuli-responsive drug release behavior of the pNIPAAm-co-GMA-Lys HG was investigated at different pH (pH 7.4, 6.2, and 4.0) and temperature (25 °C, 37 °C, and 45 °C) conditions, respectively, using curcumin (Cur) as a model anticancer drug. The Cur drug-loaded pNIPAAm-co-GMA-Lys/Cur HG showed a relatively slow drug release behavior at a physiological pH (pH 7.4) and low temperature (25 °C) condition, whereas enhanced drug release was achieved at acidic pH (pH 6.2 and 4.0) and higher temperature (37 °C and 45 °C) conditions. Furthermore, the in vitro biocompatibility and intracellular fluorescence imaging were examined using the MDA-MB-231 cell line. Therefore, we demonstrate that the synthesized pNIPAAm-co-GMA-Lys HG system with temperature- and pH-stimuli-responsive features could be promising for various applications in biomedical fields, including drug delivery, gene delivery, tissue engineering, diagnosis, antibacterial/antifouling material, and implantable devices.

Supramolecular β-Cyclodextrin-Quercetin Based Metal-Organic Frameworks as an Efficient Antibiofilm and Antifungal Agent

The loading of drugs or medicinally active compounds has recently been performed using metal-organic frameworks (MOFs), which are thought to be a new type of porous material in which organic ligands and metal ions can self-assemble to form a network structure. The quercetin (QRC) loading and biofilm application on a cyclodextrin-based metal-organic framework via a solvent diffusion approach is successfully accomplished in the current study. The antibacterial plant flavonoid QRC is loaded onto β-CD-K MOFs to create the composite containing inclusion complexes (ICs) and denoted as QRC:β-CD-K MOFs. The shifting in the chemical shift values of QRC in the MOFs may be the reason for the interaction of QRC with the β-CD-K MOFs. The binding energies and relative contents of MOFs are considerably changed after the formation of QRC:β-CD-K MOFs, suggesting that the interactions took place during the loading of QRC. Confocal laser scanning microscopy (CLSM) showed a reduction in the formation of biofilm. The results of the cell aggregation and hyphal growth are consistent with the antibiofilm activity that is found in the treatment group. Therefore, QRC:β-CD-K MOFs had no effect on the growth of planktonic cells while inhibiting the development of hyphae and biofilm in C. albicans DAY185. This study creates new opportunities for supramolecular β-CD-based MOF development for use in biological research and pharmaceutical production.

Preparation and Antimicrobial Characterization of Poly(butylene adipate-co-terephthalate)/Kaolin Clay Biocomposites

The biodegradable polymer poly(butylene adipate-co-terephthalate) (PBAT) starts decomposing at room temperature. Kaolin clay (KO) was dispersed and blended into PBAT composites using a solution-casting method. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to evaluate the structure and morphology of the composite materials. PBAT/kaolin clay composites were studied by thermogravimetric analysis (TGA). The PBAT composite loaded with 5.0 wt% kaolin clay shows the best characteristics. The biocomposites of PBAT/kaolin [PBC-5.0 (37.6MPa)] have a good tensile strength when compared to virgin PBAT (18.3MPa). The oxygen transmission rate (OTR), with ranges from 1080.2 to 311.7 (cc/m²/day), leads the KO content. By including 5.0 wt% kaolin 43.5 (g/m²/day), the water vapor transmission rate (WVTR) of the PBAT/kaolin composites was decreased. The pure PBAT must have a WVTR of 152.4 (g/m²/day). Gram-positive (S. aureus) and Gram-negative (E. coli) food-borne bacteria are significantly more resistant to the antimicrobial property of composites. The results show that PBAT/kaolin composites have great potential as food packaging materials due to their ability to decrease the growth of bacteria and improve the shelf life of packaged foods.

Heteroatom-Enhanced Porous Carbon Materials Based on Polybenzoxazine for Supercapacitor Electrodes and CO2 Capture

Through a solution method utilizing benzoxazine chemistry, heteroatoms containing porous carbons (HCPCs) were synthesized from melamine, eugenol and formaldehyde, followed by carbonization in a nitrogen atmosphere and chemical activation with KOH at three different activation temperatures, 700, 800 and 900 °C. The introduction of melamine and eugenol to the monomer produced structurally bonded nitrogen and oxygen in porous carbons. Changing the calcination temperature can alter the doping level of heteroatoms and the particle size. These carbon materials exhibit large pore size distributions, tunable pore structure, high nitrogen and oxygen contents and high surface areas, which make them suitable for use as electrode materials in supercapacitors. As a result of activating at 800 °C, the sample HCPC-800 exhibits a high specific surface area of 984 m²/g, high oxygen and nitrogen content (3.64-6.26 wt.% and 10.61-13.65 wt.%), hierarchical pore structure, high degree of graphitization and good electrical conductivity. An outstanding rate capability is also demonstrated, as well as incredible longevity, retaining the capacitance up to 83% even after 5000 cycles in a solution containing 1 M H₂SO₄. Moreover, the activated porous carbon containing nitrogen exhibits a CO₂ adsorption capacity of 3.6 and 3.5 mmol/g at 25 °C and 0 °C, respectively, which corresponds to equilibrium pressures of 1 bar.

Synthesis of Bio-Based Polybenzoxazine and Its Antibiofilm and Anticorrosive Activities

Candida albicans are highly widespread pathogenic fungi in humans. Moreover, its developed biofilm causes serious clinical problems, leading to drug failure caused by its inherent drug tolerance. Hence, the inhibition of biofilm formation and virulence characteristics provide other means of addressing infections. Polymer composites (PCs) derived from natural products have attracted increasing interest in the scientific community, including antimicrobial applications. PCs are a good alternative approach to solving this challenge because of their excellent penetration power inside biofilms. The main objectives of this study were to synthesize a novel curcumin-based polybenzoxazine polymer composite (poly(Cu-A) PC) using Mannich condensation reaction and evaluate their potency as an antibiofilm and anticorrosive candidate against C. albicans. In addition, their anticorrosive efficacy was also explored. PC exhibited significant antibiofilm efficacy versus C. albicans DAY185 by the morphologic changing of yeast to hyphae, and>90% anticorrosive efficacy was observed at a higher dose of PC. These prepared PC were safe in vivo against Caenorhabditis elegans and Raphanus raphanistrum. The study shows that a polybenzoxazine polymer composite has the potential for controlling biofilm-associated fungal infections and virulence by C. albicans, and opens a new avenue for designing PCs as antifungal, anticorrosive agents for biofilm-associated fungal infections and industrial remediation.

Thermosensitive Polymer-Modified Mesoporous Silica for pH and Temperature-Responsive Drug Delivery

A mesoporous silica-based drug delivery system (MS@PNIPAm-PAAm NPs) was synthesized by conjugating the PNIPAm-PAAm copolymer onto the mesoporous silica (MS) surface as a gatekeeper that responds to temperature and pH changes. The drug delivery studies are carried out in vitro at different pH (7.4, 6.5, and 5.0) and temperatures (such as 25 °C and 42 °C, respectively). The surface conjugated copolymer (PNIPAm-PAAm) acts as a gatekeeper below the lower critical solution temperature (LCST) (<32 °C) and as a collapsed globule structure above LCST (>32 °C), resulting in controlled drug delivery from the MS@PNIPAm-PAAm system. Furthermore, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cellular internalization results support the prepared MS@PNIPAm-PAAm NPs being biocompatible and readily taken up by MDA-MB-231 cells. The prepared MS@PNIPAm-PAAm NPs, with their pH-responsive drug release behavior and good biocompatibility, could be used as a drug delivery vehicle where sustained drug release at higher temperatures is required.