Novel polymeric hydrogel composites: Synthesis, physicochemical, mechanical and biocompatible properties

Development of temperature-regulating CR/PVA bionanocomposite films with phase change materials and antibacterial properties for ice cream packaging

This study focuses on the development of active packaging for anti-heating food packaging using film materials based on Carrageenan (CR) and polyvinyl alcohol (PVA). The aim is to effectively manage the temperature of food products during storage and transportation to preserve their quality and freshness. Temperature-controlled bionanocomposite films were synthesized by incorporating phase change materials (PCMs) into the CR/PVA blend matrix. Specifically, polyethylene glycol (PEG) was grafted onto cellulose nanocrystals supported by copper nanoparticles to create a solid-solid PCM-Cu with exceptional thermal storage efficiency. The resulting nanocomposite films exhibited buffering properties at cold chain temperatures compared to pure CR/PVA films. The presence of copper nanoparticles also contributed antibacterial activity, further ensuring food safety. These nanocomposite films demonstrate significant potential for application in food packaging, as they effectively address temperature-related challenges within the food industry. The findings highlight the effectiveness of these innovative films in preserving the freshness of ice cream even when exposed to periods outside the freezer.

Bioadhesive levan-based coaxial nanofibrous membranes with enhanced cell adhesion and mesenchymal stem cell differentiation

Conventional electrospun nanofibrous membranes have been widely used for tissue engineering scaffolds because they can mimic extracellular matrix (ECM), which plays a significant role in cell proliferation, adhesion, and differentiation. However, the inadequate mechanical strength and biological functions of electrospun nanofibrous scaffolds limit the range of their practical applications. In this study, we prepared a uniform levan-based core-shell composite (csCAL) nanofibrous membrane using the coaxial electrospinning technique. The coaxial csCAL membrane with levan and cellulose acetate (CA) as shell and core, respectively, exhibited highly enhanced mechanical properties and adhesive strength. Moreover, the unique bioadhesive nature of these membranes significantly enhanced cell attachment and proliferation, while their high biocompatibility and biodegradability hold substantial promise for application as functional cell carriers. Upon incorporating mesenchymal stem cells (MSCs) into the csCAL nanofibrous membrane, we observed enhanced osteogenesis and chondrogenesis, as evidenced by alizarin red and alcian blue staining, respectively. These results indicate that the levan-based nanofiber architecture has the potential to deliver scaffolds for supporting the differentiation of MSCs.

Development and characterization of bael fruit gum-pectin hydrogel for enhanced antimicrobial activity

Natural polymers are crucial for developing sustainable biomedical solutions, as their bioactivity, biocompatibility, and biodegradability make them superior alternatives to synthetic materials. The objective of the study is to develop and characterize a chemically modified bael fruit gum (BFG) and pectin hydrogel to enhance antimicrobial activity. Due to BFG's anionic nature, it was chemically modified to introduce cationic groups, facilitating cross-linking with pectin. Physicochemical characterization of BFG and pectin was conducted using FTIR and DSC, which confirmed functional groups and thermal stability, respectively. Hydrogel optimization was achieved through Central Composite Design (CCD). Rheological evaluations indicated shear-thinning behavior with a viscosity reduction under high shear stress, reflecting thixotropic properties. The hydrogel exhibited satisfactory erosion and swelling within 24 h, suggesting controlled release. Zeta potential measurements confirmed the hydrogel's stability, attributed to its negative surface charge. SEM revealed a porous structure, aiding in drug encapsulation and release. Antimicrobial testing showed synergistic antimicrobial effects with inhibition zones of 1.4 cm and 1.5 cm against Staphylococcus aureus and Escherichia coli, respectively. Stability studies demonstrated robustness over time. Overall, this study highlights the potential of natural polymer-based hydrogels as sustainable alternatives to synthetic polymers in pharmaceutical and biomedical fields, offering safer, environmentally friendly solutions.

Boosting Contact Electrification by Amorphous Polyvinyl Alcohol Endowing Improved Contact Adhesion and Electrochemical Capacitance

Ion conductive hydrogels are relevant components in wearable, biocompatible, and biodegradable electronics. Polyvinyl-alcohol (PVA) homopolymer is often the favored choice for integration into supercapacitors and energy harvesters as in sustainable triboelectric nanogenerators (TENGs). However, to further improve hydrogel-based TENGs, a deeper understanding of the impact of their composition and structure on devices performance is necessary. Here, it is shown how ionic hydrogels based on an amorphous-PVA (a-PVA) allow to fabricate TENGs that outperform the one based on the homopolymer. When used as tribomaterial, the Li-doped a-PVA allows to achieve a twofold higher pressure sensitivity compared to PVA, and to develop a conformable e-skin. When used as an ionic conductor encased in an elastomeric tribomaterial, 100 mW cm-2 average power is obtained, providing 25% power increase compared to PVA. At the origin of such enhancement is the increased softness, stronger adhesive contact, higher ionic mobility (> 3,5-fold increase), and long-term stability achieved with Li-doped a-PVA. These improvements are attributed to the high density of hydroxyl groups and amorphous structure present in the a-PVA, enabling a strong binding to water molecules. This work discloses novel insights on those parameters allowing to develop easy-processable, stable, and highly conductive hydrogels for integration in conformable, soft, and biocompatible TENGs.

Effect of Surface Chemistry on Hemolysis, Thrombogenicity, and Toxicity of Carbon Nanotube Doped Thermally Sprayed Hydroxyapatite Implants

Assessing blood compatibility is crucial before in vivo procedures and is considered more reliable than many in vitro tests. This study examines the physiochemical properties and blood compatibility of bioactive powders ((0.5-2 wt % carbon nanotube (CNT)/alumina)-20 wt %)) produced through a heterocoagulation colloidal technique followed by ball milling with hydroxyapatite (HAp). The 1 wt % CNT composite demonstrated a surface charge ∼5 times higher than HAp at pH 7.4, with a value of -11 mV compared to -2 mV. This increase in electrostatic charge is desirable for achieving hemocompatibility, as evidenced by a range of blood compatibility assessments, including hemolysis, blood clotting, platelet adhesion, platelet activation, and coagulation assays (prothrombin time (PT) and activated partial thrombin time (aPTT)). The 1 wt % CNT composite exhibited hemolysis ranging from 2 to 7%, indicating its hemocompatibility. In the blood clot investigation, the absorbance values for 1-2 wt % CNT samples were 0.927 ± 0.038 and 1.184 ± 0.128, respectively, indicating their nonthrombogenicity. Additionally, the percentage of platelet adhered on the 1 wt % CNT sample (∼5.67%) showed a ∼2.5-fold decrement compared to the clinically used negative control, polypropylene (∼13.73%). The PT and aPTT experiments showed no difference in the coagulation time for CNT samples even at higher concentrations, unlike HAC2 (80 mg). In conclusion, the 1 wt % CNT sample was nontoxic to human blood, making it more hemocompatible, nonhemolytic, and nonthrombogenic than other samples. This reliable study reduces the need for additional in vitro and in vivo studies before clinical trials, saving time and cost.

A disulfiram/copper gluconate co-loaded bi-layered long-term drug delivery system for intraperitoneal treatment of peritoneal carcinomatosis

To develop a long-term drug delivery system for the treatment of primary and metastatic peritoneal carcinoma (PC) by intraperitoneal (IP) injection, a disulfiram (DSF)/copper gluconate (Cu-Glu)-co-loaded bi-layered poly (lactic acid-coglycolic acid) (PLGA) microspheres (Ms) - thermosensitive hydrogel system (DSF-Ms-Cu-Glu-Gel) was established. Rate and mechanisms of drug release from DSF-Ms-Cu-Glu-Gel were explored. The anti-tumor effects of DSF-Ms-Cu-Glu-Gel by IP injection were evaluated using H22 xenograft tumor model mice. The accumulative release of DSF from Ms on the 10th day was 83.79% without burst release. When Ms were dispersed into B-Gel, burst release at 24 h decreased to 14.63%. The results showed that bis (diethyldithiocarbamate)-copper (Cu(DDC)2) was formed in DSF-Ms-Cu-Glu-Gel and slowly released from B-Gel. In a pharmacodynamic study, the mount of tumor nodes and ascitic fluid decreased in the DSF-Ms-Cu-Glu-Gel group. This was because: (1) DSF-Ms-Cu-Glu-Gel system co-loaded DSF and Cu-Glu, and physically isolated DSF and Cu-Glu before injection to protect DSF; (2) space and water were provided for the formation of Cu(DDC)2; (3) could provide an effective drug concentration in the abdominal cavity for a long time; (4) both DSF and Cu(DDC)2 were effective anti-tumor drugs, and the formation of Cu(DDC)2 occurred in the abdominal cavity, which further enhanced the anti-tumor activity. Thus, the DSF-Ms-Cu-Glu-Gel system can be potentially used for the IP treatment of PC in the future.

Dielectric barrier discharge plasma-modified chitosan flocculant and its flocculation performance

The flocculation performance of chitosan can be enhanced by grafting modification to overcome its disadvantages of poor water solubility. In this study, chitosan was modified by dielectric barrier discharge plasma and polymerized with acrylamide and aluminum chloride to synthesize a new chitosan-based flocculant, namely, chitosan-acrylamide-aluminum chloride (CA-PAC). After optimizing the synthesis conditions of CA-PAC, the best conditions were as follows: discharge time of 3 min, discharge power of 50 W, polymerization temperature of 60 °C, polymerization time of 3 h, total monomer concentration of 100 g/L, and m(AlCl3):m(CA) ratio of 2:1. Characterization was performed through SEM, XPS, FTIR, XRD, TG and 1H NMR. Results showed that the preparation of CA-PAC was successful. The influences of flocculant dosage, pH, and stirring intensity on flocculation efficiency were investigated. The removal efficiency of turbidity was 94.1 %. The investigation of the flocculation mechanism revealed that CA-PAC mainly relied on charge neutralization or the synergic action of electric neutralization, bridging, and roll-sweep under acidic and neutral conditions, but it depended on the joint action of adsorption bridging and net sweeping under alkaline conditions. This study provides new ideas for the preparation and development of modified chitosan and broadens its application in water treatment.

Development and characterization of crosslinked k-carrageenan/sericin blend with covalent agents or thermal crosslink for indomethacin extended release

Modified release of multiparticulate pharmaceutical forms is a key therapeutic strategy to reduce side effects and toxicity caused by high and repeated doses of immediate-release oral drugs. This research focused on the encapsulation of indomethacin (IND) in the crosslinked k-Car/Ser polymeric matrix by covalent and thermal methods to evaluate drug delivery modulation and properties of the crosslinked blend. Therefore, the entrapment efficiency (EE %), drug loading (DL %) and physicochemical properties of the particles were investigated. The particles presented a spherical shape and a rough surface with a mean diameter of 1.38-2.15 mm (CCA) and 1.56-1.86 mm (thermal crosslink). FTIR investigation indicated the presence of IDM in the particles and X-ray pattern showed the maintenance of crystallinity of IDM. The in vitro release in acidic medium (pH 1.2) and phosphate buffer saline solution (pH 6.8) was 1.23-6.81 % and 81-100 %, respectively. Considering the results, the formulations remained stable after 6 months. The Weibull equation was adequately fitted for all formulations and a diffusion mechanism, swelling and relaxation of chain were observed. IDM-loaded k-carrageenan/sericin/CMC increases cell viability (> 75 % for neutral red and > 81 % for MTT). Finally, all formulations present gastro-resistance, pH response and altered release and have the potential to be used as drug delivery careers.

Gold nanoparticles-decorated peptide hydrogel for antifouling electrochemical dopamine determination

A reliable and brief ultralow fouling electrochemical sensing system capable of monitoring targets in complex biological media was constructed and validated based on gold nanoparticles-peptide hydrogel-modified screen-printed electrode. The self-assembled zwitterionic peptide hydrogel was prepared by a newly designed peptide sequence of Phe-Phe-Cys-Cys-(Glu-Lys)₃ with the N-terminal modified with a fluorene methoxycarbonyl group. The thiol groups on cysteine of the designed peptide are able to self-assemble with AuNPs to form a three-dimensional nanonetwork structure, which showed satisfactory antifouling capability in complex biological media (human serum). The developed gold nanoparticles-peptide hydrogel-based electrochemical sensing platform displayed notably sensing properties for dopamine determination, with a wide linear range (from 0.2 nM to 1.9 μM), a low limit of detection (0.12 nM), and an excellent selectivity. This highly sensitive and ultralow fouling electrochemical sensor was fabricated via simple preparation with concise components that avoid the accumulation of layers with single functional material and complex activation processes. This ultralow fouling and highly sensitive strategy based on the gold nanoparticles-peptide hydrogel with a three-dimensional nanonetwork offers a solution to the current situation of various low-fouling sensing systems facing impaired sensitivity and provides a potential path for the practical application of electrochemical sensors.

Chitosan based smart polymer composites: Fabrication and pH-Responsive behavior for bio-medical applications

This research aimed to synthesize Chitosan/PVA-blank and a series of Cs/PVA/Sepolite based pH-sensitive membranes using a solution casting process. The synthesized Cs/PVA-blank and Cs/PVA/Sep based membranes were investigated via SEM, FTIR, XRD, and TGA techniques. The SEM results of Cs/PVA/Sep based membrane reveal that the hydrolytic stability and strength were improved in acidic and basic media owing to the incorporation of sepiolite content into chitosan. The characteristic band at 3741 cm^-1 in the FTIR spectra of the Cs/PVA/Sep membrane confirmed the successful synthesis. The obtained XRD results showed higher d-spacing for Cs/PVA/Sep membranes as compared to the Cs/PVA-blank membranes owing to the intercalation of chitosan in the interlayer spacing of the sepiolite. The obtained TGA results show higher thermally stability for Cs/PVA/Sep membrane as compared to the Cs/PVA-blank sample due to the interaction of sepiolite content with the chitosan matrix. The obtained hydrolytic and swelling studies revealed that the Cs/PVA/Sep membrane displayed enhanced stability in basic and neutral media while showing minimum swelling in an acidic medium. The water uptake ability was checked for Cs/PVA/-blank and Cs/PVA/Sep-60% membrane and the results exhibited that the Cs/PVA/-blank membrane had maximum water uptake value as compared to the Cs/PVA/Sep-60% membrane. While those with a considerable amount of filler had the lowest water uptake values. As Sepolite content increased, the water uptake % values decreases because of weakness in H-bonding (of hydrophilic groups) and due to intercalation in Sepolite layers during polymer formation.

Saccharomyces cerevisiae-incorporated and sucrose-rich sodium alginate film: An effective antioxidant packaging film for longan preservation

A sodium alginate (SA) film incorporated with Saccharomyces cerevisiae (SE) and sucrose (SU) was fabricated to control the quality and pericarp browning of longan. The SE with satisfactory glutathione production was selected as the antioxidant agent. The scanning electron microscopy (SEM) results revealed that the SU-rich SA film could be used as an effective carrier to protect the cell integrity of SE. The FTIR and mechanical property results indicated that the SA-SE film with the incorporation of SU has good flexibility due to the existence of hydrogen bonds. Notably, the cell viability of the SE was significantly improved with the addition of SU, which positively affects the antioxidant property of the film during the storage period. Finally, the SA-SE-3.0%SU films obviously improved the quality and pericarp browning of longan. The SA-based film incorporated with SU and SE may be established as a novel antioxidant fruit packaging material.

Infrared spectroscopy and flow cytometry studies on the apoptotic effect of nano-chrysin in HeLa cells

Mapping the structural changes in membrane lipids, proteins, polysaccharides and nucleic acids has opened new channels for understanding the mode of action of anticancer natural products. Earlier, we synthesized chrysin nanoparticles (NChr) with good bioavailability, and characterized its size, surface charge, entrapment efficiency, and drug release pattern using PLGA polymer. NChr induced concentration dependent cytotoxicity in HeLa cells with an IC₅₀ of 61.54 ± 1.2 µM in comparison with free chrysin with IC₅₀ of 86.51 ± 2.9 µM. Since nanoparticles interact dynamically with cell membranes, organelles, proteins and DNA, it is necessary to understand the interplay of nanodrug induced macromolecular changes in cancer cells. In this work, we obtained signatures of NChr-induced biochemical changes in HeLa cells by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy technique coupled with flow cytometry. NChr induced cell membrane disruption, G1 phase cell cycle arrest, and increased externalization of phosphatidylserine leading to apoptosis indicating the biochemical perturbations in membrane lipids and DNA of HeLa cells in comparison with untreated cells. The 1300-1000 cm^-1 spectral region indicated NChr interaction with the ribose sugar backbone and DNA denaturation. Spectral range 1800-1400 cm^-1 indicated a concentration dependent decrease in α helical and β sheet structures which may lead to protein degradation during apoptosis. The spectral range 3000-2800 cm^-1 indicated the lipid peroxidation in response to NChr treatment. This is the first study describing the bio-macromolecular changes induced by a nano encapsulated drug and can pave the way to investigate unconventional modes of action for bioactive formulations.

Probing into crystallography and morphology properties of MoS2 nanoflowers synthesized via temperature dependent hydrothermal method

This paper reports the formation of flower-like hierarchical molybdenum disulfide (MoS2) nanoparticles following a simple one-step hydrothermal process with varying temperatures (200 °C and 220 °C). The as-synthesized particles were examined crystallographically by X-ray diffraction (XRD) method which revealed the formation of hexagonal MoS2 (2H-MoS2) and that the crystallite size of the particles increased with increasing hydrothermal temperature. Surface morphological characteristics of the particles were investigated by a field emission scanning electron microscope (FESEM) and interesting details were revealed such as the rounded 3D flower-like microstructure of the MoS2 particles and the petals of the flowers were composed of platelets built up by stacked-up MoS2 nanosheets. With the increase in hydrothermal temperature, the interlayer spacing of stacked layers of intense (002) plane is slightly decreased although the crystallinity of the material is improved. Both diameter and thickness of the nanoflowers and the nanoplatelets increased twice with increasing the temperatures. A visual crystallographic perspective was presented through simulation of 3D wireframe unit cell associated with the individual lattice planes as observed in the XRD pattern of the samples. In addition, a plausible growth mechanism is proposed for the formation of the obtained MoS2 nanoflowers on the basis of experimental observations and analysis.

A stretchable and healable elastomer with shape memory capability based on multiple hydrogen bonds

Although a wide range of self-healing materials have been reported by researchers, it is still a challenge to endow exceptional mechanical properties and shape memory characteristics simultaneously in a single material. Inspired by the structure of natural silk, herein, we have adopted a simple synthetic method to prepare a kind of elastomer (HM-PUs) with stiff, healable and shape memory capabilities assisted by multiple hydrogen bonds. The self-healing elastomer exhibits a maximum tensile strength of 39 MPa, toughness of 111.65 MJ m⁻³ and self-healing efficiency of 96%. Moreover, the recuperative efficiency of shape memory could reach 100%. The fundamental study of HM-PUs will facilitate the development of flexible electronics and medical materials.

Although a wide range of self-healing materials have been reported by researchers, it is still a challenge to endow exceptional mechanical properties and shape memory characteristics simultaneously in a single material.

Levan-chitosan blend films: Preparation, structural, physical properties and application in pork packaging

Conventional fossil fuel-based packaging materials often brings of food safety and serious environmental pollution. It is significant to develop an environmentally-friendly packaging material. In this work, a levan-chitosan (LE/CS) blend film was fabricated via the solution casting method. The films were evaluated by Fourier transform infrared spectroscopy and X-ray diffraction, indicating the formation of hydrogen bonds between chitosan and levan. The mechanical properties of LE/CS films demonstrated a mechanical strength higher than CS films, and the best tensile strength appeared at a ratio of LE/CS (1:1) up to 18.78 ± 0.73 MPa. The addition of levan caused a significant increase in absorption of UV light with a reduction in swelling water of the blend films from 29.13 ± 0.53 % of chitosan film to 2.07 ± 0.27 % of LE/CS (1:1) film. A higher contact angle and lower WVP were observed for LE/CS blend films. LE/CS blend films were then used as packaging material for fresh pork and were well maintained the qualities. The study suggested that the new blend film might have a good prospect as a food packaging material.

Atomic Force Microscopy (AFM) on Biopolymers and Hydrogels for Biotechnological Applications-Possibilities and Limits

Atomic force microscopy (AFM) is one of the microscopic techniques with the highest lateral resolution. It can usually be applied in air or even in liquids, enabling the investigation of a broader range of samples than scanning electron microscopy (SEM), which is mostly performed in vacuum. Since it works by following the sample surface based on the force between the scanning tip and the sample, interactions have to be taken into account, making the AFM of irregular samples complicated, but on the other hand it allows measurements of more physical parameters than pure topography. This is especially important for biopolymers and hydrogels used in tissue engineering and other biotechnological applications, where elastic properties, surface charges and other parameters influence mammalian cell adhesion and growth as well as many other effects. This review gives an overview of AFM modes relevant for the investigations of biopolymers and hydrogels and shows several examples of recent applications, focusing on the polysaccharides chitosan, alginate, carrageenan and different hydrogels, but depicting also a broader spectrum of materials on which different AFM measurements are reported in the literature.

A test strip electrochemical disposable by 3D MXA/AuNPs DNA-circuit for the detection of miRNAs

The simple and reliable detection of microRNAs is of great significance for studying the biological functions, molecular diagnosis, disease treatment and targeted drug therapy of microRNA. In this study, we introduced a novel Ti₃C₂Tx (MXene) aerogels (denoted as MXA) composite gold nano-particles (AuNPs)-modified disposable carbon fiber paper (CFP) electrode for the label-free and sensitive detection of miRNA-155. Firstly, in the presence of MXene, graphene oxide (GO) and ethylenediamine (EDA), the 3D MXene hydrogel was formed by self-assembly method, and then adding the freeze-dried 3D MXA dropwise to CFP. Subsequently, electrodepositing AuNPs on the CFP/MXA was done to construct a 3D disposable DNA-circuit test strip with excellent interface. Under the optimum experimental conditions, the detection limit of 3D disposable DNA circuit strip for miRNA-155 was 136 aM (S/N = 3). The CFP/MXA/AuNPs (CMA) electrode also has a wide dynamic range (20 fM to 0.4 μM), with a span of 4 orders of magnitude. Notably, we also tested the practicality of the sensor in 8 clinical samples. The technological innovations in the detection and quantification of microRNA in this work may be helpful to the study new aspects of microRNA biology and the development of diagnosis.