In this paper, we propose a new shape memory polymer (SMP) composite with excellent near-infrared (NIR)-photoresponsive shape memory performance and biodegradability. The composite is fabricated by ...using piperazine-based polyurethane (PU) as thermo-responsive SMP incorporated with black-phosphorus (BP) sheets as NIR photothermal nanofillers. Under 808 nm light irradiation, the incorporated BP sheets with concentration of only 0.08 wt% enable rapid temperature increase over the glass temperature of PU and trigger the shape change of the composite with shape recovery rate of ∼100%. The in vitro and in vivo toxicity examinations demonstrate the good biocompatibility of the PU/BP composite, and it degrades naturally into non-toxic carbon dioxide and water from PU and non-toxic phosphate from BP. By implanting PU/BP columns into back subcutis and vagina of mice, they exhibit excellent shape memory activity to change their shape quickly under moderate 808 nm light irradiaiton. Such SMP composite enable the development of intelligent implantable devices, which can be easily controlled by the remote NIR light and degrade gradually after performing the designed functions in the body.
The worldwide increasing consumption of the phosphonates 2-phosphonobutane-1,2,4-tricarboxylic acid PBTC, 1-hydroxyethane 1,1-diphosphonic acid HEDP, nitrilotris(methylene phosphonic acid) NTMP, ...ethylenediamine tetra(methylene phosphonic acid) EDTMP and diethylenetriamine penta(methylene phosphonic acid) DTPMP over the past decades put phosphonates into focus of environmental scientists and agencies, as they are increasingly discussed in the context of various environmental problems. The hitherto difficult analysis of phosphonates contributed to the fact that very little is known about their concentrations and behavior in the environment. This work critically reviews the existing literature up to the year 2016 on the potential environmental relevance of phosphonates, their biotic and abiotic degradability, and their removal in wastewater treatment plants (WWTPs). Accordingly, despite their stability against biological degradation, phosphonates can be removed with relatively high efficiency (>80%) in WWTPs operated with chemical phosphate precipitation. In the literature, however, to our knowledge, there is no information as to whether an enhanced biological phosphorus removal alone is sufficient for such high removal rates and whether the achievable phosphonate concentrations in effluents are sufficiently low to prevent eutrophication. It is currently expected that phosphonates, although being complexing agents, do not remobilize heavy metals from sediments in a significant amount since the phosphonate concentrations required for this (>50μg/L) are considerably higher than the concentrations determined in surface waters. Various publications also point out that phosphonates are harmless to a variety of aquatic organisms. Moreover, degradation products thereof such as N-(phosphonomethyl)glycine and aminomethylphosphonic acid are regarded as being particularly critical. Despite their high stability against biological degradation, phosphonates contribute to eutrophication due to abiotic degradation (mainly photolysis). Furthermore, the literature reports on the fact that phosphonates in high concentrations interfere with phosphate precipitation in WWTPs. Thus, it is recommended to remove phosphonates, in particular from industrial wastewaters, before discharging them into water bodies or WWTPs.
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•Phosphonates are removed with >80% from wastewater treatment plants (WWTPs).•Sole enhanced biological phosphorus removal may not lead to such high removal rates.•To date, phosphonates may not remobilize heavy metals from sediment significantly.•Phosphonates, except some degradation products, are harmless to most aquatic organisms.•Phosphonates contribute to eutrophication and interfere with phosphate removal in WWTPs.
The three-dimensional printing (3DP) also known as the additive manufacturing (AM), a novel and futuristic technology that facilitates the printing of multiscale, biomimetic, intricate ...cytoarchitecture, function-structure hierarchy, multi-cellular tissues in the complicated micro-environment, patient-specific scaffolds, and medical devices. There is an increasing demand for developing 3D-printed products that can be utilized for organ transplantations due to the organ shortage. Nowadays, the 3DP has gained considerable interest in the tissue engineering (TE) field. Polylactide (PLA) and polycaprolactone (PCL) are exemplary biomaterials with excellent physicochemical properties and biocompatibility, which have drawn notable attraction in tissue regeneration. Herein, the recent advancements in the PLA and PCL biodegradable polymer-based composites as well as their reinforcement with hydrogels and bio-ceramics scaffolds manufactured through 3DP are systematically summarized and the applications of bone, cardiac, neural, vascularized and skin tissue regeneration are thoroughly elucidated. The interaction between implanted biodegradable polymers, in-vivo and in-vitro testing models for possible evaluation of degradation and biological properties are also illustrated. The final section of this review incorporates the current challenges and future opportunities in the 3DP of PCL- and PLA-based composites that will prove helpful for biomedical engineers to fulfill the demands of the clinical field.
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•Polylactide (PLA) and polycaprolactone (PCL) are biocompatible and biodegradable biomaterials.•3D printing techniques which develop PLA- and PCL-based scaffolds are illustrated.•Soft and hard tissue engineering applications of these biomaterials are elucidated.•Recent advancements from PLA and PCL perspectives are demonstrated.
Persistency of organic chemicals is a key property in their environmental risk assessment. Information on persistency is often derived from the results of biodegradability screening tests such as the ...ready biodegradability tests (RBTs). RBTs are, however, not designed for this purpose and suffer from several problems that lead to a high variability of the results and, hence, to difficulties in their interpretation. The origin and exposure history of the inocula used for biodegradability testing can lead to highly variable outcomes. Microbial adaptation to chemicals and its impact on biodegradation needs further investigation in order to have a better understanding of their effects on persistency assessments of chemicals. It is well described that microbial adaptation stimulates biodegradation of organic chemicals. Several mechanisms responsible for these phenomena have been described, amongst which are i) shifts in community composition or abundances, ii) mutations within populations, iii) horizontal gene transfer or iv) recombination events. These adaptation processes may well be mimicked under laboratory conditions, but the outcome remains difficult to predict as we lack a fundamental understanding of the adaptive responses. This review aims to bring together our current knowledge regarding microbial adaptation and its implication for the testing of biodegradation of chemicals.
Drug delivery technology has a wide spectrum, which is continuously being upgraded at a stupendous speed. Different fabricated nanoparticles and drugs possessing low solubility and poor ...pharmacokinetic profiles are the two major substances extensively delivered to target sites. Among the colloidal carriers, nanolipid dispersions (liposomes, deformable liposomes, virosomes, ethosomes, and solid lipid nanoparticles) are ideal delivery systems with the advantages of biodegradation and nontoxicity. Among them, nano-structured lipid carriers and solid lipid nanoparticles (SLNs) are dominant, which can be modified to exhibit various advantages, compared to liposomes and polymeric nanoparticles. Nano-structured lipid carriers and SLNs are non-biotoxic since they are biodegradable. Besides, they are highly stable. Their (nano-structured lipid carriers and SLNs) morphology, structural characteristics, ingredients used for preparation, techniques for their production, and characterization using various methods are discussed in this review. Also, although nano-structured lipid carriers and SLNs are based on lipids and surfactants, the effect of these two matrixes to build excipients is also discussed together with their pharmacological significance with novel theranostic approaches, stability and storage.
Drug delivery technology has a wide spectrum, which is continuously being upgraded at a stupendous speed.
Azobenzenes are archetypal molecules that have a central role in fundamental and applied research. Over the course of almost two centuries, the area of azobenzenes has witnessed great achievements; ...azobenzenes have evolved from simple dyes to 'little engines' and have become ubiquitous in many aspects of our lives, ranging from textiles, cosmetics, food and medicine to energy and photonics. Despite their long history, azobenzenes continue to arouse academic interest, while being intensively produced for industrial purposes, owing to their rich chemistry, versatile and straightforward design, robust photoswitching process and biodegradability. The development of azobenzenes has stimulated the production of new coloured and light-responsive materials with various applications, and their use continues to expand towards new high-tech applications. In this Review, we highlight the latest achievements in the synthesis of red-light-responsive azobenzenes and the emerging application areas of photopharmacology, photoswitchable adhesives and biodegradable materials for drug delivery. We show how the synthetic versatility and adaptive properties of azobenzenes continue to inspire new research directions, with limits imposed only by one's imagination.
Utilizing nanoparticles in packaging materials has proven to be an effective method for enhancing the longevity and security of food products. Carbon dots (CDs) have a wide variety of potential ...applications in food packaging. A flexible film made of thermoplastic chitosan (TPC) and heteroatom-doped CDs has been created using a wet chemical blending technique. These CDs reinforced TPC based hybrid films exhibit flexibility, antioxidant properties, biodegradability, and resistance to UV radiation. The mechanical strength of the films was assessed through uniaxial tensile testing, while their low-temperature flexibility was evaluated by measuring the sub-ambient (∼-30°C) glass transition temperature (Tg). Additionally, the presence of CDs directly influences the permeability of oxygen and moisture, resulting in a reduction in comparison to neat chitosan films, a vital characteristic for packaging materials. Over a span of three weeks, the TPC-based hybrid films demonstrated a progressive weight loss (∼75 %), indicating their biodegradability. Furthermore, these films have shown promise as antibacterial and antioxidant materials. The durability of the films and the absence of chemical release from the embedded CDs within the TPC matrices were also verified, underscoring their considerable potential as antibacterial, biodegradable, and antioxidant packaging materials within the food industry.
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•Flexible film made of thermoplastic chitosan and heteroatom-doped carbon dots.•CDs enhance antioxidant properties, biodegradability, and UV radiation resistance.•CDs reduce permeability of oxygen and moisture, crucial for packaging materials.•Films showed progressive weight loss (∼75 %), indicating biodegradability.•CDs/TPC films showed promising antibacterial and antioxidant behavior.
Chemical dispersants are extensively used for marine oil spill remediation. However, the increased toxicity and low biodegradability of these dispersants restrict their employment in the marine ...environment. Hence, in this work, we have developed an eco-friendly formulation composed of an ionic liquid,1-butyl-3-methylimidazolium lauroyl sarcosinate BMIMLausar and sorbitan monooleate (Span) 80. Micellar and interfacial parameters, dispersion effectiveness, as well as the toxicity and biodegradability of the developed formulation were investigated. Micellar properties confirmed a high degree of synergism among the surfactant molecules and the formation of stable micelle. The dispersion effectiveness, at dispersant-to-oil ratio (DOR) of 1:25 (v/v), against three crude oils (Arab, Ratawi, and Doba) was assessed. We achieved a dispersion effectiveness of 68.49%, 74.05%, and 83.43% for Ratawi, Doba, and Arab crude oil, respectively, using a 70:30 (w/w) ratio of Span 80 to BMIMLausar. Furthermore, the results obtained from optical microscopy and particle size analysis (PSA) indicated that the oil droplet size decreased with higher DOR. Additionally, acute toxicity experiments were conducted on zebrafish (Danio rerio) using the developed formulation, confirming its non-toxic behavior, with LC50 values of 800 mg/L after 96 h. The formulation also exhibited high biodegradability, with only 25.01% of the original quantity remaining after 28 days. Hence, these results suggest that the new formulation has the potential to be a highly effective and environmentally friendly dispersant for oil spill remediation.
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•New oil spill dispersant formulated with surface-active ionic liquid and Span 80.•The formulated dispersant was found to be highly effective for crude oil dispersion.•Acute toxicity tests revealed the non-toxic behavior of the formulated oil dispersant.•The oil dispersant was found to be readily biodegradable.
Anaerobic digestion (AD) of solid wastes is an efficient and economical alternative to convert complex organic matter into clean energy. Effectiveness of AD depends on different physio-chemical ...characteristics of solid wastes. In the present study, an attempt is made to develop an anaerobic digestability index (ADI) which will indicate the biodegradability of solid wastes. Based on a literature review 26 parameters were first identified to be influencing the AD which were narrowed down to 11 using the Delphi method. A participatory-based technique (analytic hierarchy process) was then adopted for assigning weightages to the selected parameters. Rating curves for the selected parameters were drawn with expert opinion using the Delphi method. Based on the sensitivity analysis, weighted additive function was selected for aggregating the subindex with the relative weightages. ADI was then applied to different types of solid wastes proving it to be a robust index for determining the anaerobic digestability.
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•A composite indicator to determine the anaerobic digestability of wastes is developed.•Delphi method and AHP are used to select the significant parameters and their weightages.•Rating curves are drawn through Delphi method to normalize the parameters.•Weighted additive aggregation function is selected through sensitivity analysis.•ADI is proved to be a robust index for indicating anaerobic biodegradability.
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