Novel Bioplastic Based on PVA Functionalized with Anthocyanins: Synthesis, Biochemical Properties and Food Applications.

Over the last ten years, researchers' efforts have aimed to replace the classic linear economy model with the circular economy model, favoring green chemical and industrial processes. From this point of view, biologically active molecules, coming from plants, flowers and biomass, are gaining considerable value. In this study, firstly we focus on the development of a green protocol to obtain the purification of anthocyanins from the flower of Callistemon citrinus, based on simulation and on response surface optimization methodology. After that, we utilize them to manufacture and add new properties to bioplastics belonging to class 3, based on modified polyvinyl alcohol (PVA) with increasing amounts from 0.10 to 1.00%. The new polymers are analyzed to monitor morphological changes, optical properties, mechanical properties and antioxidant and antimicrobial activities. Fourier transform infrared spectroscopy (FTIR) spectra of the new materials show the characteristic bands of the PVA alone and a modification of the band at around 1138 cm-1 and 1083 cm-1, showing an influence of the anthocyanins' addition on the sequence with crystalline and amorphous structures of the starting materials, as also shown by the results of the mechanical tests. These last showed an increase in thickening (from 29.92 µm to approx. 37 µm) and hydrophobicity with the concomitant increase in the added anthocyanins (change in wettability with water from 14° to 31°), decreasing the poor water/moisture resistance of PVA that decreases its strength and limits its application in food packaging, which makes the new materials ideal candidates for biodegradable packaging to extend the shelf-life of food. The functionalization also determines an increase in the opacity, from 2.46 to 3.42 T%/mm, the acquisition of antioxidant activity against 2,2-diphenyl-1-picrylhdrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, in the ferric reducing power assay, the antimicrobial (bactericidal) activity against different Staphylococcus aureus strains at the maximum tested concentration (1.00% of anthocyanins). On the whole, functionalization with anthocyanins results in the acquisition of new properties, making it suitable for food packaging purposes, as highlighted by a food fresh-keeping test.

Polyphenolic truxillic acid crosslinked sodium alginate film with notable antimicrobial and biodegradable properties for food packaging.

This work demonstrated an innovative antimicrobial and biodegradable food packaging film CBDA-10-SA which was prepared by crosslinking a natural polyphenolic truxillic acid (cyclobutane-dicarboxylic acid, CBDA-10) and sodium alginate (SA). The CBDA-10-SA film exhibited improved tensile strength (148 MPa) and UV shielding capabilities. The maximum thermal decomposition temperature was achieved of 249 °C. Compared to SA film, CBDA-10-SA showed increased antibacterial activities. In food packaging test, the CBDA-10-SA inhibited the rapid growth of potential of hydrogen (pH) value, slowed down the weight loss, reduced total plate count (TPC) value of pork, and delayed the spoilage process of pork. Notably, CBDA-10-SA displayed remarkable degradability in soil, with 60 % degrading in four weeks. In this study, CBDA-10-SA showed enhanced physicochemical and mechanical properties compared to traditional SA film. Those improvements make it anticipated to be used in not only food packaging but also mechanical, pharmaceutical, and agricultural fields.

Bioactive chitosan films: Integrating antibacterial, antioxidant, and antifungal properties in food packaging.

In this work, chitosan was combined with bio-vanillin (BV) and kaolin clay (KC) to create a novel antifungal and biodegradable food packaging film. The chitosan/KC/BV film exhibited an antioxidant capacity of 80 % as measured by DPPH assay, which was significantly higher than that of the chitosan film which has 55.6 %). The film also demonstrated strong antimicrobial activity with a reduction of 90 % in the growth of E. coli and S. aureus compared to the control. Additionally, the chitosan/KC/BV film showed a 75 % reduction in fungal growth compared to chitosan film. Furthermore, the water vapor permeability of the chitosan film was reduced as 5.38 with the addition of KC/BV. The degradation study revealed that the chitosan/KC film degraded by 88 % within 20 days under composting conditions. Additionally, fresh-cut apple slices were used to examine the effectiveness of chitosan/KC/BV film as a packaging material. The fruit's weight loss and browning index showed satisfactory food preservation. Our research suggests that the chitosan/KC/BV film has great potential for use in the food sector due to its strong antioxidant, antimicrobial, and biodegradable properties.

The synergistic effect of polyphenols and polypeptides for plant-based bioplastic film - Enhanced UV resistance, antioxidant and antibacterial performance.

The exceptional biodegradability and active biological functions of bio-based packaging materials have attracted increasing interest. In this study, a bioplastic film was developed by introducing simultaneously polyphenols (tea polyphenols, TPs) and peptides (nisin) into a soy protein isolate/sodium alginate (SPI/SA) based film-forming matrix. The research results revealed that the dynamic coordinated interaction between TPs and nisin enhanced mechanical properties, UV-resistance, and thermal stability of bioplastic films. Furthermore, the bioplastic film exhibited antibacterial activity and antioxidant properties. Significantly, biofilm growth of Staphylococcus aureus treated with TPs-5/Nisin-5 bioplastic film was inhibited by 91.12% compared to the blank group. The shelf life of beef with TPs-5/Nisin-5 bioplastic film was prolonged by 2 days because of the synergistic effect of TPs and nisin. Additionally, the bioplastic film biodegraded in the natural environment about 21 days. This environmentally friendly regeneration strategy and the integration of advantageous functions provided ideas for the development of active food packaging.

Converting fruit peels into biodegradable, recyclable and antimicrobial eco-friendly bioplastics for perishable fruit preservation.

The development of biodegradable antimicrobial bioplastics for food packaging holds great promise for solving the pollution and safety problems caused by petrochemical plastics and spoiled food. Herein, a natural active-bioplastic synthesized from citrus peel biomass is presented for perishable fruit preservation. These plastics are characterized by the nanoscale entanglement and recombinant hydrogen bonding between the endogenous pectin, polyphenols and cellulose micro/nanofibrils. They have attractive flexibility, tensile strength, gas barrier properties and antimicrobial activities, and can effectively extend the shelf life of perishable fruits such as banana and mango when used as food packaging. Cytotoxicity, degradability tests and life-cycle assessment show that these plastics had excellent nontoxicity and can be safely degraded or easily recycled. This work demonstrates a sustainable strategy for converting peel waste into eco-friendly bioplastics, providing a unique and novel insight into radically reducing the pollution and life-health threats posed by petrochemical plastics and spoiled food.

Development of cellulose/ZnO based bioplastics with enhanced gas barrier, UV-shielding effect and antibacterial activity.

Development of renewable and biodegradable plastics with good properties, such as the gas barrier, UV-shielding, solvent resistance, and antibacterial activity, remains a challenge. Herein, cellulose/ZnO based bioplastics were fabricated by dissolving cellulose carbamate in an aqueous solution of NaOH/Zn(OH)42-, followed by coagulation in aqueous Na2SO4 solution, and subsequent hot-pressing. The carbamate groups detached from cellulose, and ZnO which transformed from cosolvent to nanofiller was uniformly immobilized in the cellulose matrix during the dissolution/regeneration process. The appropriate addition of ZnO (below 10.67 wt%) not only improved the mechanical properties but also enhanced the water and oxygen barrier properties of the material. Additionally, our cellulose/ZnO based bioplastic demonstrated excellent UV-blocking capabilities, increased water contact angle, and enhanced antibacterial activity against S. aureus and E. coli, deriving from the incorporation of ZnO nanoparticles. Furthermore, the material exhibited resistance to organic solvents such as acetone, THF, and toluene. Indeed, the herein developed cellulose/ZnO based bioplastic presents a promising candidate to replace petrochemical plastics in various applications, such as plastic toys, anti-UV guardrails, window shades, and oil storage containers, offering a combination of favorable mechanical, gas barrier, UV-blocking, antibacterial, and solvent-resistant properties.

Biodegradable plastic formulated from chitosan of Aristeus antennatus shells with castor oil as a plasticizer agent and starch as a filling substrate.

Biodegradable plastics are those subjected easily to a degradation process, in which they can be decomposed after disposal in the environment through microbial activity. 30 bioplastic film formulations based only on chitosan film were used in the current investigation as a positive control together with chitosan film recovered from chitin-waste of locally obtained Aristeus antennatus. Additionally, castor oil was used as a plasticizer. While the yield of chitosan was 18% with 7.65% moisture content and 32.27% ash in the shells, the isolated chitin had a degree of deacetylation (DD) of 86%. The synthesized bioplastic films were characterized via numerous criteria. Firstly, the swelling capacity of these biofilms recorded relatively high percentages compared to polypropylene as synthetic plastic. Noticeably, the FTIR profiles, besides DSC, TGA, and XRD, confirmed the acceptable characteristics of these biofilms. In addition, their SEM illustrated the homogeneity and continuity with a few straps of the chitosan film and showed the homogeneous mixes of chitosan and castor oil with 5 and 20%. Moreover, data detected the antibacterial activity of different bioplastic formulas against some common bacterial pathogens (Enterococcus feacalis, Kelbsiella pnumina, Bacillus subtilis, and Pseudomonas aeruginosa). Amazingly, our bioplastic films have conducted potent antimicrobial activities. So, they may be promising in such a direction. Further, the biodegradability efficacy of bioplastic films formed was proved in numerous environments for several weeks of incubation. However, all bioplastic films decreased in their weights and changed in their colors, while polypropylene, was very constant all the time. The current findings suggest that our biofilms may be promising for many applications, especially in the field of food package protecting the food, and preventing microbial contamination, consequently, it may help in extending the shelf life of products.

Development of Plumeria alba extract supplemented biodegradable films containing chitosan and cellulose derived from bagasse and corn cob waste for antimicrobial food packaging.

With the increase in global plastic pollution due to conventional plastic packaging (petroleum-derived), bioplastics have emerged as an alternative green source for practising a circular economy. This research aimed to extract cellulose from bagasse and corn cob waste and utilized in mixed form to prepare bioplastic film. The mixed cellulose was further reinforced with natural substances such as chitosan, bentonite, and P. alba extract. These newly developed bioplastics films were characterized by various physical tests like film thickness, moisture content, water solubility and spectroscopic techniques such as Fourier transform infrared (FTIR), scanning electron microscopy-energy dispersive spectroscopic (SEM-EDX), thermal gravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectroscopy for opacity testing. The results revealed the enhanced bioplastic thermal and mechanical characteristics through robust interactions between cellulose and bentonite molecules. Moreover, incorporating chitosan solution as reinforcements in bio-composite films resulted in improved water barrier properties. The results indicated lower absorption in the UV range of 250-400 nm, attributed to the absence of UV-absorbing groups. Finally, their biodegradability was tested in soil, and 85.3 % weight loss of bioplastic films was observed after 50 days of the experiment which is the main task of this research. The antimicrobial properties of bioplastic films have been evaluated, and showed an inhibition zone of 16 mm against E. coli. After 12 days of incubation of sherbet berries, complete spoilage is identified in the control group compared to those covered with the bioplastic film. This outcome is attributed to the antioxidant and antimicrobial activities provided by chitosan and P. alba extract in the bioplastic film. The comprehensive outcomes of this study suggest the potential future adoption of these entirely bio-derived, environmentally sustainable and biodegradable bioplastic films as a viable substitute for the plastic packaging currently present in the market.

Prominent toxicity of isocyanates and maleic anhydrides to Caenorhabditis elegans: Multilevel assay for typical organic additives of biodegradable plastics.

Biodegradable plastics (BDP) are increasingly applied; however, there has been of concerns about their environmental safety, especially from nondegradable additive compositions. Until now, data of ecotoxicity of BDP additives is scarce. Here, nematode C. elegans was used to comparatively evaluate toxicity of an isocyanate additive, i.e., Hexamethylene diisocyanate (HDI), a maleic anhydride, i.e., Diallyl maleate (DIM), and other four BDP organic additives. These additives caused lethality of nematodes at µg L-1 level, of lowest LC50 value of HDI/DIM. Uniform exposure to these additives resulted in various degrees of inhibitions in body volumes and longevity, indicating developmental toxicity. Moreover, BDP additives induced significant elevations of gst-4 expression, especially mean 123.54 %/234.29 % increase in HDI/DIM group, but reduced ges-1 expression, which indicates oxidative damages and mitochondrial dysfunction. BDP additives further caused inhibition in locomotor and food intake/excretion behavior, and related damages of glutamatergic neurons and GABAergic neurons, indicating their neurotoxicity. We found HDI and DIM presented relatively strong effects on susceptible endpoints including lethality, gst-4, mean lifespan, food intake and excretion behavior. Overall, this study suggests prominent ecotoxic risk of isocyanates and maleic anhydrides as BDP additives, which is significant for the selection of environmentally friendly BDP additives.

Persistent versus transient, and conventional plastic versus biodegradable plastic? -Two key questions about microplastic-water exchange of antibiotic resistance genes.

The ubiquitous microplastics (MPs) in water environment play an important role in the dissemination of antibiotic resistance genes (ARGs) due to their exchange between floating MPs and receiving waters. However, whether the ARG exchange is persistent or transient and what are the differences in ARG exchange between conventional plastics and biodegradable plastics are the two key issues to be addressed. In this study, biodegradable PBAT and non-biodegradable PET MPs were chosen to explore the MP-water ARG exchange after the MPs floated to the receiving waters. The results demonstrated that the active exchange of ARGs between MPs and receiving waters occurred, which, however, were transient for most of ARGs. The relative abundance of ARGs both on the MPs and in the waters rapidly decreased to the initial or lower levels within 4 weeks. Approximately 25-50% (ARG subtype number ratio) of studied ARG subtypes were introduced into the receiving waters by MPs, and 35-65% of studied ARG subtypes went through fluctuation in terms of abundance on MPs and in the receiving water. ARGs tended to converge between MPs and the receiving waters with time. Furthermore, the ARG exchange between MPs and waters facilitated horizontal gene transfer (HGT). IntI1 and tnpA05 played the crucial roles in HGT, which was indicated by their correlated change with most ARGs; in contrast, tnpA04 showed the obvious lagging responses. The biodegradable MP of PBAT generally accumulated higher levels of most ARGs including multidrug resistant genes than the non-biodegradable MP of PET. The transient exchange of most ARGs between MPs and water implies that the on-off hitchhiking of ARGs on MPs in aquatic environment may not exert significant influence on ARG transmission. However, compared with the conventional plastics, the biodegradable MPs might pose much higher ARG dissemination risks due to the higher enrichment of ARGs particularly with people's ever-increasingly usage. Enough attention must be paid to this emerging issue.

Biodegradability, physical, mechanical and antimicrobial attributes of starch nanocomposites containing chitosan nanoparticles.

This study aimed to develop a plasticized starch (PS) based film loaded with chitosan nanoparticles (CNPs, 1, 2, 3, and 4%) as a reinforcing and antibacterial agent. We examined the morphology, biodegradability, mechanical, thermo-mechanical, and barrier properties of the PS/CNPs films. The antimicrobial activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria was investigated by colony forming unit (CFU) and disc diffusion methods. A dense structure was obtained for all PS/CNPs films and, thus, their complete biodegradation occurred in more days than neat PS. The increase in the CNPs percentage led to improved mechanical behaviour and barrier properties. PS-CNPs composite films revealed inhibition zones against both E. coli and S. aureus, with the 100% reduction in CFU against S. aureus. The current study exhibited that PS-CNPs films were more effective in inhibiting bacteria growth than neat PS film, confirming the composite films potential application as antimicrobial food packaging.

Photodynamic therapy with the dual-mode association of IR780 to PEG-PLA nanocapsules and the effects on human breast cancer cells.

IR780 is a near-infrared fluorescent dye, which can be applied as a photosensitizer in photodynamic (PDT) and photothermal (PTT) therapies and as a biodistribution tracer in imaging techniques. We investigated the growth and migration inhibition and mechanism of death of breast tumor cells, MCF-7 and MDA-MB-231, exposed to polymeric nanocapsules (NC) comprising IR780 covalently linked to the biodegradable polymer PLA (IR-PLA) and IR780 physically encapsulated (IR780-NC) in vitro. Both types of NC had mean diameters around 120 nm and zeta potentials around -40 mV. IR-PLA-NC was less cytotoxic than IR780 NC to a non-tumorigenic mammary epithelial cell line, MCF-10A, which is an important aspect of selectivity. Free-IR780 was more cytotoxic than IR-PLA-NC for MCF-7 and MDA-MB-231 cells after illumination with a 808 nm laser. IR-PLA NC was effective to inhibit colony formation (50%) and migration (30-40%) for both cancer cell lines. MDA-MB-231 cells were less sensitive to all IR780 formulations compared to MCF-7 cells. Cell uptake was higher with IR-PLA-NC than with IR780-NC and free-IR780 in both cancer cell lines (p < 0.05). NC uptake was higher in MCF-7 than in MDA-MB-231 cells. IR-PLA-NC induced a higher percentage of apoptosis upon illumination in MDA-MB-231 than in MCF-7 cells. The necrosis mechanism of death predominated in treatments with free-IR780 and with encapsulated IR780 NC, suggestive of damages at the plasma membrane. IR780 conjugated with PLA increased the apoptotic pathway and demonstrated potential as a multifunctional theranostic agent for breast cancer treatment with increased cellular uptake, photodynamic activity and more reliable tracking in cell-image studies.

Release of Cinnamaldehyde and Thymol from PLA/Tilapia Fish Gelatin-Sodium Alginate Bilayer Films to Liquid and Solid Food Simulants, and Japanese Sea Bass: A Comparative Study.

This study aimed to develop an active biodegradable bilayer film and to investigate the release behaviors of active compounds into different food matrices. Cinnamaldehyde (CI) or thymol (Ty) was encapsulated in ß-cyclodextrin (ß-CD) to prepare the active ß-CD inclusion complex (ß-CD-CI/ß-CD-Ty). The tilapia fish gelatin-sodium alginate composite (FGSA) containing ß-CD-CI or ß-CD-Ty was coated on the surface of PLA film to obtain the active bilayer film. Different food simulants including liquid food simulants (water, 3% acetic acid, 10% ethanol, and 95% ethanol), solid dry food simulant (modified polyphenylene oxide (Tenax TA)), and the real food (Japanese sea bass) were selected to investigate the release behaviors of bilayer films into different food matrixes. The results showed that the prepared ß-CD inclusion complexes distributed evenly in the cross-linking structure of FGSA and improved the thickness and water contact angle of the bilayer films. Active compounds possessed the lowest release rates in Tenax TA, compared to the release to liquid simulants and sea bass. CI and Ty sustained the release to the sea bass matrix with a similar behavior to the release to 95% ethanol. The bilayer film containing ß-CD-Ty exhibited stronger active antibacterial and antioxidant activities, probably due to the higher release efficiency of Ty in test mediums.

Biodegradability of Novel Polylactide and Polycaprolactone Materials with Bacteriostatic Properties Due to Embedded Birch Tar in Different Environments.

The microbial biodegradation of new PLA and PCL materials containing birch tar (1-10% v/v) was investigated. Product of dry distillation of birch bark (Betula pendula Roth) was added to polymeric materials to obtain films with antimicrobial properties. The subject of the study was the course of enzymatic degradation of a biodegradable polymer with antibacterial properties. The results show that the type of the material, tar concentration, and the environment influenced the hydrolytic activity of potential biofilm degraders. In the presence of PCL films, the enzyme activities were higher (except for α-D-glucosidase) compared to PLA films. The highest concentration of birch tar (10% v/v) decreased the activity of hydrolases produced by microorganisms to the most significant extent; however, SEM analysis showed the presence of a biofilm even on plastics with the highest tar content. Based on the results of the biological oxygen demand (BOD), the new materials can be classified as biodegradable but, the biodegradation process was less efficient when compared to plastics without the addition of birch tar.

Highly Efficient Modular Construction of Functional Drug Delivery Platform Based on Amphiphilic Biodegradable Polymers via Click Chemistry.

Amphiphilic copolymers with pendant functional groups in polyester segments are widely used in nanomedicine. These enriched functionalities are designed to form covalent conjugates with payloads or provide additional stabilization effects for encapsulated drugs. A general method is successfully developed for the efficient preparation of functional biodegradable PEG-polyester copolymers via click chemistry. Firstly, in the presence of mPEG as initiator, Sn(Oct)2-catalyzed ring-opening polymerization of the α-alkynyl functionalized lactone with D,L-lactide or ε-caprolactone afforded linear mPEG-polyesters bearing multiple pendant alkynyl groups. Kinetic studies indicated the formation of random copolymers. Through copper-catalyzed azide-alkyne cycloaddition reaction, various small azido molecules with different functionalities to polyester segments are efficiently grafted. The molecular weights, polydispersities and grafting efficiencies of azido molecules of these copolymers were investigated by NMR and GPC. Secondly, it is demonstrated that the resulting amphiphilic functional copolymers with low CMC values could self-assemble to form nanoparticles in aqueous media. In addition, the in vitro degradation study and cytotoxicity assays indicated the excellent biodegradability and low cytotoxicity of these copolymers. This work provides a general approach toward the preparation of functional PEG-polyester copolymers in a quite efficient way, which may further facilitate the application of functional PEG-polyesters as drug delivery materials.

Essential oils loaded-chitosan nanocapsules incorporation in biodegradable starch films: A strategy to improve fruits shelf life.

Thermoplastic starch (TPS) films filled with chitosan nanocapsules (CN) containing essential oils (EO) were prepared aiming active packaging. Two different EOs were studied: Ho wood (H) and Cinnamon (C). Besides, different capsules concentrations were investigated (1, 3, and 5 wt%), and the films were evaluated by chemical structure, thermal stability, crystallinity, water vapor permeability, antimicrobial assays, and potential application for strawberry packaging. The TPS/CN-Ho wood films showed a strong interaction between chitosan-starch, mainly for 3 and 5 wt%, confirmed by XRD. The FT-Raman spectra of TPS/CN-Cinnamon film indicated that Cinnamon EO quickly migrated to starch films, probably due to the new crystal structure, named C-type, affecting the film's water permeability. The addition of 1 and 3 wt% CN loaded with Ho wood or Cinnamon EO to the films decreased the water permeability. 3 wt% CN was the optimum concentration to inhibit the Escherichia coli or Bacillus subtillis growth on the films, confirming their biological activity. The films' preservation properties were evaluated using strawberries, and films with 1 or 3 wt% loaded-CN could extend the strawberries' shelf life without fungi contamination. The developed TPS films can be used as active food packaging or other films for biomedical or pharmaceutical applications.

Biodegradable Polymersomes with Structure Inherent Fluorescence and Targeting Capacity for Enhanced Photo-Dynamic Therapy.

Biodegradable nanostructures displaying aggregation-induced emission (AIE) are desirable from a biomedical point of view, due to the advantageous features of loading capacity, emission brightness, and fluorescence stability. Herein, biodegradable polymers comprising poly (ethylene glycol)-block-poly(caprolactone-gradient-trimethylene carbonate) (PEG-P(CLgTMC)), with tetraphenylethylene pyridinium-TMC (PAIE) side chains have been developed, which self-assembled into well-defined polymersomes. The resultant AIEgenic polymersomes are intrinsically fluorescent delivery vehicles. The presence of the pyridinium moiety endows the polymersomes with mitochondrial targeting ability, which improves the efficiency of co-encapsulated photosensitizers and improves therapeutic index against cancer cells both in vitro and in vivo. This contribution showcases the ability to engineer AIEgenic polymersomes with structure inherent fluorescence and targeting capacity for enhanced photodynamic therapy.

Alkenyl succinic anhydride modified tree-gum kondagogu: A bio-based material with potential for food packaging.

Tree gums are a class of abundantly available carbohydrate polymers that have not been explored thoroughly in film fabrication for food packaging. Films obtained from pristine tree gums are often brittle, hygroscopic, and lack mechanical strength. This study focuses on the chemical modification of gum kondagogu using long-chain alkenyl groups of dodecenyl succinic anhydride (DDSA), an esterifying agent that introduces a 12-carbon hydrophobic chain to the kondagogu structure. The esterification reaction was confirmed by 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The effect of nano-cellulose as an additive on various film properties was investigated. The developed films were characterized for their mechanical, morphological, optical, barrier, antibacterial, and biodegradable properties. The inclusion of long-chain carbon groups acted as internal plasticizers and resulted in an amorphous structure with better film-forming ability, improved hydrophobicity, and higher elongation at break values. The modified films exhibited antibacterial properties and excellent biodegradability under aerobic conditions.

Development and characterization of chitosan and acrylic acid-based novel biodegradable polymeric films for soil conditioning.

In this study, biodegradable polymeric films (BPFs) based on chitosan and acrylic acid cross-linked with 3-aminopropyl triethoxysilane (APTES) were developed for water retention and soil-conditioning applications in areas sufferings from water scarcity. A series of BPFs were prepared by varying the amount of silica nanoparticles (SiNPs) (0.67% to 2.6%) and a correlation of the optimum amount of SiNPs with thermal stability, morphology, swellability (at various pH), degradability, and anti-microbial activity were deduced. The obtained results showed that the NP 8 (containing 2.51% of SiNPs) exhibited the maximum absorption capacity (1815%) in distilled water, whereas NP6 (including 1.88% of SiNPs) expressed the maximum thermal stability (T50% at 375.61 °C). The microscopic images further strengthen this observation because the maximum number of micro-porous cavities was shown on the surface of NP8. The time-dependent swelling response in distilled water accomplished that hydrophilicity (percentage swelling) of films was enhanced with an increase in the concentration of SiNPs. All BPFs samples exhibited inhibitory response against both gram-positive (for Staphylococcus aureus was 2.9 cm for NP6) and gram-negative (for Escherichia coli was 0.9 cm for NP8) bacteria. The biodegradation test inferred that the degradation of BPFs in soil did not affect the soil fertility as nano-silica is proven as growth-promoting miniatures. It can be concluded that these BPFs may be efficiently employed in the agriculture sector for water retention and as a soil conditioner.

Janus 3D printed dynamic scaffolds for nanovibration-driven bone regeneration.

The application of physical stimuli to cell cultures has shown potential to modulate multiple cellular functions including migration, differentiation and survival. However, the relevance of these in vitro models to future potential extrapolation in vivo depends on whether stimuli can be applied "externally", without invasive procedures. Here, we report on the fabrication and exploitation of dynamic additive-manufactured Janus scaffolds that are activated on-command via external application of ultrasounds, resulting in a mechanical nanovibration that is transmitted to the surrounding cells. Janus scaffolds were spontaneously formed via phase-segregation of biodegradable polycaprolactone (PCL) and polylactide (PLA) blends during the manufacturing process and behave as ultrasound transducers (acoustic to mechanical) where the PLA and PCL phases represent the active and backing materials, respectively. Remote stimulation of Janus scaffolds led to enhanced cell proliferation, matrix deposition and osteogenic differentiation of seeded human bone marrow derived stromal cells (hBMSCs) via formation and activation of voltage-gated calcium ion channels.