Synthesis and characterization of an environmentally friendly PHBV/PEG copolymer network as a phase change material

Comparison of the Influence of Oxygen Groups Introduced by Graphene Oxide on the Activity of Carbon Felt in Vanadium and Anthraquinone Flow Batteries

An increasing number of studies focus on organic flow batteries (OFBs) as possible substitutes for the vanadium flow battery (VFB), featuring anthraquinone derivatives, such as anthraquinone-2,7-disulfonic acid (2,7-AQDS). VFBs have been postulated as a promising energy storage technology. However, the fluctuating cost of vanadium minerals and risky supply chains have hampered their implementation, while OFBs could be prepared from renewable raw materials. A critical component of flow batteries is the electrode material, which can determine the power density and energy efficiency. Yet, and in contrast to VFBs, studies on electrodes tailored for OFBs are scarce. Hence, in this work, we propose the modification of commercial carbon felts with reduced graphene oxide (rGO) and poly(ethylene glycol) for the 2,7-AQDS redox couple and to preliminarily assess its effects on the efficiency of a 2,7-AQDS/ferrocyanide flow battery. Results are compared to those of a VFB to evaluate if the benefits of the modification are transferable to OFBs. The modification of carbon felts with surface oxygen groups introduced by the presence of rGO enhanced both its hydrophilicity and surface area, favoring the catalytic activity toward VFB and OFB reactions. The results are promising, given the improved behavior of the modified electrodes. Parallels are established between the electrodes of both FB technologies.

Bovine Serum Albumin Nanoparticles Enhanced the Intranasal Bioavailability of Silybin in Rats

Silybin (SLB), an important flavonoid from silymarin, displays significant hepatoprotective, anticancer, antioxidant, and neuroprotective effects. However, its therapeutic efficacy is limited by its low solubility and bioavailability. To address these challenges, we engineered bovine serum albumin (BSA) nanoparticles (NP) loaded with SLB (BSA-NP/SLB) using the coacervation method. BSA-SLB NP exhibited a spherical shape, a mean size of 197 nm, a polydispersity index of 0.275, a zeta potential of -34 mV, and an entrapment efficiency of 67%. X-ray diffraction analysis indicated amorphization of SLB upon encapsulation. Formulation stability was upheld over 180 days. In vitro release assays demonstrated controlled diffusion-erosion release, with approximately 40% SLB released within 0.5 h and 100% over 12 h. Intranasal administration of BSA-NP/SLB in rats improved SLB bioavailability by fourfold compared to free SLB. These findings highlight the promising potential of intranasally administered BSA-NP/SLB as an alternative approach to enhance SLB bioavailability, paving the way for innovative therapeutic applications.

Facile Synthesis of Highly Stretchable, Tough, and Photodegradable Hydrogels

Recently, highly stretchable and tough hydrogels that are photodegradable on-demand have been reported. Unfortunately, the preparation procedure is complex due to the hydrophobic nature of the photocrosslinkers. Herein, a simple method is reported to prepare photodegradable double-network (DN) hydrogels that exhibit high stretchability, toughness, and biocompatibility. Hydrophilic ortho-nitrobenzyl (ONB) crosslinkers incorporating different poly(ethylene glycol) (PEG) backbones (600, 1000, and 2000 g mol-1 ) are synthesized. These photodegradable DN hydrogels are prepared by the irreversible crosslinking of chains by using such ONB crosslinkers, and the reversible ionic crosslinking between sodium alginate and divalent cations (Ca2+ ). Remarkable mechanical properties are obtained by combining ionic and covalent crosslinking and their synergistic effect, and by reducing the length of the PEG backbone. The rapid on-demand degradation of these hydrogels is also demonstrated by using cytocompatible light wavelength (λ = 365 nm) that degrades the photosensitive ONB units. The authors have successfully used these hydrogels as skin-worn sensors for monitoring human respiration and physical activities. A combination of excellent mechanical properties, facile fabrication, and on-demand degradation holds promise for their application as the next generation of substrates or active sensors eco-friendly for bioelectronics, biosensors, wearable computing, and stretchable electronics.

A novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-PEG-melatonin composite scaffold enhances for inhibiting bone tumor recurrence and enhancing bone regeneration

Introduction: Postoperative comprehensive treatment has become increasingly important in recent years. This study was to repair tissue defects resulting from the removal of diseased tissue and to eliminate or inhibit the recurrence and metastasis of residual tumors under the condition of reducing the systemic side effects of chemotherapeutic drugs. To address these challenges, multifunctional scaffolds based local drug delivery systems will be a promising solution. Methods: An optimal drug-loaded scaffold material PHBV-mPEG5k (PP5) was prepared, which is biocompatible, hydrophilic and biodegradable. Furthermore, this material showed to promote bone healing, and could be conveniently prepared into porous scaffold by freeze-drying the solution. By means of introducing melatonin (MT) into the porous surfaces, the MT loaded PP5 scaffold with desirable sustained release ability was successfully prepared. The effectiveness of the MT loaded PP5 scaffold in promoting bone repair and anti-tumor properties was evaluated through both in vivo and in vitro experiments. Results and Discussion: The MT loaded PP5 scaffold is able to achieve the desired outcome of bone tissue repair and anti-bone tumor properties. Furthermore, our study demonstrates that the PP5 scaffold was able to enhance the anti-tumor effect of melatonin by improving cellular autophagy, which provided a therapeutic strategy for the comprehensive postoperative treatment of osteosarcoma.

Investigation of the Effects of Chain Extender on Material Properties of PLA/PCL and PLA/PEG Blends: Comparative Study between Polycaprolactone and Polyethylene Glycol

This study investigated the effect of the Joncryl concentration on the properties of polylactide/poly(ε-caprolactone) (PLA/PCL) and PLA/poly(ethylene glycol) (PEG) blends. The addition of Joncryl influenced the properties of both PLA-based blends. In the blend of PLA/PCL blends, the addition of Joncryl reduced the size of PCL droplets, which implies the compatibility of the two phases, while PLA/PEG blends showed a co-continuous type of morphology at 0.1% and 0.3 wt.% of Joncryl loading. The crystallinity of PCL and PEG was studied on both PLA/PCL and PLA/PEG blend systems. In both scenarios, the crystallinity of the blends decreased upon the addition of Joncryl. Thermal stabilities were shown to depend on the addition of Joncryl. The toughness increased when 0.5 wt.% of Joncryl was added to both systems. However, the stiffness of PLA/PCL decreased, while the stiffness of PLA/PEG increased with the increasing concentration of Joncryl. This study provides new insight into the effect of chain extenders on the compatibility of PLA-based blends.

Microcrystalline cellulose grafted hyperbranched polyester with roll comb structure for synergistic toughening and strengthening of microbial PHBV/bio-based polyester elastomer composites

The brittle feature of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is the major challenge that strongly restricts its application at present. Successfully synthesized bio-based engineering polyester elastomers (BEPE) were combined with PHBV to create entirely bio-composites with the intention of toughening PHBV. Herein, the 2,2-Bis(hydroxymethyl)-propionic acid (DMPA) was grafted onto microcrystalline cellulose (MCC) and then further transformed into hyperbranched polyester structure via polycondensation. The modified MCC, named MCHBP, had plenty of terminal hydroxyl groups, which get dispersed between PHBV and BEPE. Besides, a large number of terminal hydroxyl groups of MCHBP can interact with the carbonyl groups of PHBV or BEPE in a wide range of hydrogen bonds, and subsequently increase the adhesion and stress transfer between the PHBV and BEPE. The tensile toughness and the elongation at break of the PHBV/BEPE composites with 0.5phr MCHBP were improved by 559.7 % and 221.8 % in comparison to those of PHBV/BEPE composites. Results also showed that MCHBP can play a heterogeneous nucleation effect on the crystallization of PHBV. Therefore, this research can address the current issue of biopolymers' weak mechanical qualities and may have uses in food packaging.

Paliperidone palmitate as model of heat-sensitive drug for long-acting 3D printing application

In this work, two technologies were used to prepare long-acting implantable dosage forms in the treatment of schizophrenia. Hot-melt extrusion (HME) as well as fused deposition modelling (FDM) were used concomitantly to create personalized 3D printed implants. Different formulations were prepared using an amorphous PLA as matrix polymer and different solid-state plasticizers. Paliperidone palmitate (PP), a heat sensitive drug prescribed in the treatment of schizophrenia was chosen as model drug. After extrusion, different formulations were characterized using DSC and XRD. Then, an in vitro dissolution test was carried out to discriminate the formulation allowing a sustained drug release of PP. The formulation showing a sustained drug release of the drug was 3D printed as an implantable dosage form. By modulating the infill, the release profile was related to the proper design of tailored dosage form and not solely to the solubility of the drug. Indeed, different release profiles were achieved over 90 days using only one formulation. In addition, a stability test was performed on the 3D printed implants for 3 months. The results showed the stability of the amorphous state of PP, independently of the temperature as well as the integrity of the matrix and the drug.

Leak-free and shape-stabilized phase change composites with radial spherical SiO2 scaffolds for thermal management

A shape-stabilized phase change composite with high heat resistance was prepared by the strategy of adsorbing the phase change medium PEG by radial spherical SiO2 (RSSiO2) nanospheres.

Sandwich-Structured, Hydrophobic, Nanocellulose-Reinforced Polyvinyl Alcohol as an Alternative Straw Material

An environmentally friendly, hydrophobic polyvinyl alcohol (PVA) film was developed as an alternative to commercial straws for mitigating the issue of plastic waste. Nontoxic and biodegradable cellulose nanocrystals (CNCs) and nanofibers (CNFs) were used to prepare PVA nanocomposite films by blade coating and solution casting. Double-sided solution casting of polyethylene-glycol–poly(lactic acid) (PEG–PLA) + neat PLA hydrophobic films was performed, which was followed by heat treatment at different temperatures and durations to hydrophobize the PVA composite films. The hydrophobic characteristics of the prepared composite films and a commercial straw were compared. The PVA nanocomposite films exhibited enhanced water vapor barrier and thermal properties owing to the hydrogen bonds and van der Waals forces between the substrate and the fillers. In the sandwich-structured PVA-based hydrophobic composite films, the crystallinity of PLA was increased by adjusting the temperature and duration of heat treatment, which significantly improved their contact angle and water vapor barrier. Finally, the initial contact angle and contact duration (at the contact angle of 20°) increased by 35% and 40%, respectively, which was a significant increase in the service life of the biodegradable material-based straw.

Scalable Flexible Phase Change Materials with a Swollen Polymer Network Structure for Thermal Energy Storage

3D porous structural materials are proved to be enticing candidates for the fabrication of high-performance organic phase change materials (PCMs), but the stringent fabrication process and poor processability greatly hampered their commercialization. Herein, flexible leakage-proof composite PCMs with pronounced comprehensive performance are fabricated by a scalable polymer swelling strategy without using any solvent, in which the paraffin wax (PW) segment is confined in a robust flexible 3D polymer network, giving rise to the composite PCMs with excellent form stability even at 160 °C, a high latent heat energy storage density of 133.6 J/g, and an outstanding thermal conductivity of up to ∼5.11 W/mK. More importantly, the mass production of the flexible composite phase change fiber, film, and bulk products can be achieved by adopting mature processing technologies. These resultant composite PCMs exhibit promising thermal management ability to solve the overheating problem of electronics and high-efficiency solar-thermal energy conversion capacity.

A Novel Sustained Anti-Inflammatory Effect of Atorvastatin-Calcium PLGA Nanoparticles: In Vitro Optimization and In Vivo Evaluation

Atorvastatin Calcium (At-Ca) has pleiotropic effect as anti-inflammatory drug beside its main antihyperlipidemic action. Our study was conducted to modulate the anti-inflammatory effect of At-Ca to be efficiently sustained for longer time. Single oil-water emulsion solvent evaporation technique was used to fabricate At-Ca into polymeric nanoparticles (NPs). In vitro optimization survey was performed on Poly(lactide-co-glycolide) (PLGA) loaded with At-Ca regrading to particle size, polydispersity index (PDI), zeta potential, percent entrapment efficiency (% EE), surface morphology and in vitro release pattern. In vitro drug-polymers interactions were fully scanned using Fourier-Transform Infrared Spectroscopy (FTIR) and Differential Scanning calorimetry (DSC) proving that the method of fabrication is an optimal strategy maintaining the drug structure with no interaction with polymeric matrix. The optimized formula with particle size (248.2 ± 15.13 nm), PDI (0.126 ± 0.048), zeta potential (-12.41 ± 4.80 mV), % EE (87.63 ± 3.21%), initial burst (39.78 ± 6.74%) and percent cumulative release (83.63 ± 3.71%) was orally administered in Male Sprague-Dawley rats to study the sustained anti-inflammatory effect of At-Ca PLGA NPs after carrageenan induced inflammation. In vivo results demonstrate that AT-Ca NPs has a sustained effect extending for approximately three days. Additionally, the histological examination revealed that the epidermal/dermal layers restore their typical normal cellular alignment with healthy architecture.

A New Nanocomposite Packaging Based on LASiS-Generated AgNPs for the Preservation of Apple Juice

Designing bioactive materials, with controlled metal ion release, exerting a significant biological action and associated to low toxicity for humans, is nowadays one of the most important challenges for our community. The most looked-for nanoantimicrobials are capable of releasing metal species with defined kinetic profiles, either by slowing down or inhibiting bacterial growth and pathogenic microorganism diffusion. In this study, laser ablation synthesis in solution (LASiS) has been used to produce bioactive Ag-based nanocolloids, in isopropyl alcohol, which can be used as water-insoluble nano-reservoirs in composite materials like poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Infrared spectroscopy was used to evaluate the chemical state of pristine polymer and final composite material, thus providing useful information about synthesis processes, as well as storage and processing conditions. Transmission electron microscopy was exploited to study the morphology of nano-colloids, along with UV-Vis for bulk chemical characterization, highlighting the presence of spheroidal particles with average diameter around 12 nm. Electro-thermal atomic absorption spectroscopy was used to investigate metal ion release from Ag-modified products, showing a maximum release around 60 ppb, which ensures an efficient antimicrobial activity, being much lower than what recommended by health institutions. Analytical spectroscopy results were matched with bioactivity tests carried out on target microorganisms of food spoilage.

Smart fibers for energy conversion and storage

Fibers have played a critical role in the long history of human development. They are the basic building blocks of textiles. Synthetic fibers not only make clothes stronger and more durable, but are also customizable and cheaper. The growth of miniature and wearable electronics has promoted the development of smart and multifunctional fibers. Particularly, the incorporation of functional semiconductors and electroactive materials in fibers has opened up the field of fiber electronics. The energy supply system is the key branch for fiber electronics. Herein, after a brief introduction on the history of smart and functional fibers, we review the current state of advanced functional fibers for their application in energy conversion and storage, focusing on nanogenerators, solar cells, supercapacitors and batteries. Subsequently, the importance of the integration of fiber-shaped energy conversion and storage devices via smart structure design is discussed. Finally, the challenges and future direction in this field are highlighted. Through this review, we hope to inspire scientists with different research backgrounds to enter this multi-disciplinary field to promote its prosperity and development and usher in a truly new era of smart fibers.

Preparation and Evaluation of Eudragit L100-PEG Proliponiosomes for Enhanced Oral Delivery of Celecoxib

PEGylated Eudragit L100 (ELP)-containing proliponiosomes (PLNs) were developed for improved oral delivery of celecoxib (CXB). The successful introduction of PEG 2000 or 5000 to Eudragit L100 (EL) was confirmed via proton nuclear magnetic resonance analysis of which calculated molar substitution ratio of PEG to EL was 36.0 or 36.7, respectively. CXB, ELP, phospholipid, and non-ionic surfactants were dissolved in dimethyl sulfoxide and lyophilized to produce CXB-loaded PLNs (CXB@PLNs). The physical state of CXB@PLNs was evaluated using differential scanning calorimetry and powder X-ray diffractometry, which revealed that crystalline CXB was transformed into amorphous form after the fabrication procedure. The reconstitution of CXB@PLNs in aqueous media generated CXB-loaded liponiosomes with nano-sized mean diameters and spherical morphology. CXB@PLNs displayed enhanced dissolution rate and permeability compared to CXB suspension. In vivo pharmacokinetic studies performed on rats demonstrated the improved oral bioavailability of CXB@PLNs compared to that of CXB suspension. No serious systemic toxicity was observed in the blood biochemistry tests performed on rats. These results suggest that the developed PLNs could be promising oral delivery systems for improving the bioavailability of poorly water-soluble drugs, such as CXB.

Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) in Bacillus aryabhattai and cytotoxicity evaluation of PHBV/poly(ethylene glycol) blends

The study described poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) accumulation in Bacillus aryabhattai PHB10 for the first time and evaluated the polymer induced cytotoxicity in-vitro with PHBV/poly(ethylene glycol) (PEG) blends. The B. aryabhattai strain produced 2.8 g/L PHBV, equivalent to 71.15% of cell dry mass in a medium supplemented with propionic acid, after 48 h incubation. The optimum temperature and pH for the copolymer accumulation was 31 °C and 7, respectively. The gas chromatography-mass spectrometry and nuclear magnetic resonance analyses confirmed the polymer obtained as PHBV. The differential scanning calorimetry analysis revealed that the melting point of the material as 90 °C and its thermal stability up to 220 °C. The average molecular weight (Mn) and polydispersity index of the sample was estimated by gel permeation chromatography analysis and observed as 128.508 kDa and 2.82, respectively. The PHBV showed tensile strength of 10.3 MPa and elongation at break of 13.3%. The PHBV and their blends with PEG were tested for cytotoxicity on human keratinocytes (HaCaT cells) and the cells incubated with PHBV/PEG2kDa blends were 99% viable, whereas with the PHBV alone showed comparatively higher cytotoxicity. The significant improvement in the cell viability of PHBV/PEG2kDa blends indicates its potential as a candidate for skin graft applications.

Morphology and crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polyhedral oligomeric silsesquioxane hybrids

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polyhedral oligomeric silsesquioxane (PHBV/POSS) hybrids with different POSS contents of 5, 10, 15, 20, 25 and 30 wt% were prepared by solution casting. The composition, crystallization and melting behavior, crystal structure, spherulite morphology, surface morphology, and tensile properties of PHBV/POSS hybrids were characterized by EDS, DSC, FTIR, XRD, HSPOM, AFM and a tensile testing machine. The results showed that POSS was well dispersed in the PHBV matrix. PHBV and POSS crystals coexisted in the hybrids. The crystallinity of pure PHBV was larger than that of PHBV/POSS hybrids. POSS restricted the crystallization of PHBV in PHBV/POSS hybrids. With the increase of POSS content, the crystallinity of PHBV/POSS hybrids decreased from 56.8 (pure PHBV) to 33.6% (PHBV/POSS hybrid with 30 wt%). However, the introduction of POSS did not affect the spherulite morphology of PHBV. The Avrami equation was used to describe the isothermal crystallization kinetics of PHBV/POSS hybrids. The results showed that as the crystallization temperature increased, the crystallization rate became slow. In addition, POSS can improve the tensile properties of PHBV.

Modification and Potential Application of Short-Chain-Length Polyhydroxyalkanoate (SCL-PHA)

As the only kind of naturally-occurring biopolyester synthesized by various microorganisms, polyhydroxyalkanoate (PHA) shows a great market potential in packaging, fiber, biomedical, and other fields due to its biodegradablity, biocompatibility, and renewability. However, the inherent defects of scl-PHA with low 3HV or 4HB content, such as high stereoregularity, slow crystallization rate, and particularly the phenomena of formation of large-size spherulites and secondary crystallization, restrict the processing and stability of scl-PHA, as well as the application of its products. Many efforts have focused on the modification of scl-PHA to improve the mechanical properties and the applicability of obtained scl-PHA products. The modification of structure and property together with the potential applications of scl-PHA are covered in this review to give a comprehensive knowledge on the modification and processing of scl-PHA, including the effects of physical blending, chemical structure design, and processing conditions on the crystallization behaviors, thermal stability, and mechanical properties of scl-PHA.