Synthesis Of Biopolymers Research Articles

Coupling of CO2 Electrolysis with Parallel and Semi-Automated Biopolymer Synthesis - Ex-Cell and without Downstream Processing.

Important improvements have been achieved in developing the coupling of electrochemical CO2 reduction to formate with its subsequent microbial conversion to polyhydroxybutyrate (PHB) by Cupriavidus necator. The CO2 based formate electrosynthesis was optimised by electrolysis parameter adjustment and application of Sn based gas diffusion electrodes reaching almost 80 % Faradaic efficiency at 150 mA cm-2. Thereby, catholyte with the high formate concentration of 441±9 mmol L-1 was generated as feedstock without intermediate downstream processing for semi-automated formate feeding into a fed-batch reactor system. Moreover, microbial formate conversion to PHB was studied further, optimised, and successfully scaled from shake flasks to semi-automated bioreactors. Therein, a PHB per formate ratio of 16.5±4.0 mg g-1 and a PHB synthesis rate of 8.4±2.1 mg L-1 OD-1 h-1 were achieved. By this process combination, an almost doubled overall process yield of 22.3±5.5 % was achieved compared to previous reports. The findings allow a detailed evaluation of the overall CO2 to PHB conversion, providing the basis for potential technical exploitation.

Tropical Fruit Waste Management: Developing Pectin-based Biopolymer from Durian Rind (Durio zibethinus)

Durian (Durio zibethinus) is a popular native tropical fruit and is largely produced in Southeast Asia. In Indonesia, 1.71 million metric tons of durian were produced in 2022. However, this high production may lead to organic waste issues due to the large amount of durian rind generation. About 60 – 75% of the durian is the rind, which is mostly discarded, hard to be decomposed, and not utilized optimally. Meanwhile, the durian rind poses as a potential reservoir containing high concentrations of cellulose and pectin. Therefore, this research aimed to (1) extract pectin content from durian rind and (2) synthesize and characterize pectin-based biopolymer films. First, the pectin was extracted from dried durian rind powder using acid extraction and alcoholic precipitation methods. Then, biopolymer synthesis was done by mixing formulations of pectin, chitosan, ethylene glycol, and glycerol solutions to form thin films. About 0.13 – 0.71 g of pectin (0.46% of the pectin yield) was extracted per 100 g of dried durian rind powder. The FTIR spectroscopy results of the extracted pectin confirmed the presence of the O - H groups at 3327.83 cm-1, which indicated the pyranose ring, the main characteristic of pectin. Pectin-based biopolymer films were produced with thickness, transparency, and tensile strength of 0.01 – 0.07 mm, 7.40 - 40.50, and 1.26 – 2.69 MPa, respectively. The findings of the soil burial degradation test for biodegradability showed that the biopolymer experienced weight loss of up to 62% in 14 days. Considering the potential utilization of the durian rind for developing biopolymers as value-added bioproducts from agricultural biomass, tropical fruit waste management should be done properly in the future. This also can be offered as one of the alternative solutions for plastic substitution with proper development in the future.

Microbial synthesis of Bio-polymers of Polyhydroxybutyrate (PHB) from spent wash as low-cost carbon source in the medium

The use of plastics is widespread, from the automotive to the medical industries. The plastic takes a very long time to break down and is bad for the environment. It is best to use biodegradable plastics rather than such non-biodegradable polymers. The biopolymer polyhydroxybutyrate (PHB) has characteristics similar to those of synthetic polymers and is vulnerable to microbial deterioration in the environment. Microorganisms like yeast and bacteria produce PHB when under stress. The primary objective of the study was to isolate bacterial strains from soil capable of generating PHB. Sudan Black B was used to detect PHB for the initial screening of the isolates. The method of digestion with sodium hypochlorite was used to extract PHB. PHBs that had been extracted were measured using UV-VIS spectroscopy and identified using FTIR and DSC.

Insights into structure and activity of a UDP-GlcNAc 2-epimerase involved in secondary cell wall polymer biosynthesis in Paenibacillus alvei.

S-layer anchoring in Paenibacillus alvei is enabled by a non-covalent interaction between an S-layer homology domain trimer and a secondary cell wall polymer (SCWP), ensuring the structural integrity of the bacterial cell wall. Within the SCWP repeat, pyruvylated ManNAc serves as the ligand and the UDP-GlcNAc-2-epimerase MnaA supplies UDP-ManNAc to SCWP biosynthesis. To better understand SCWP biosynthesis and identify strategies for inhibiting pathogens with comparable cell wall architecture, like Bacillus anthracis, MnaA and rational variants were produced in E. coli and their kinetic constants determined. The effect of UDP-GlcNAc as a predicted allosteric activator and tunicamycin as a potential inhibitor of MnaA was tested in vitro supported by molecular docking experiments. Additionally, wild-type MnaA was crystallized. We present the crystal structure of unliganded P. alvei MnaA resolved at 2.20 Å. It adopts a GT-B fold consistent with other bacterial non-hydrolyzing UDP-GlcNAc 2-epimerases. A comparison of amino acid sequences reveals conservation of putative and known catalytic and allosteric-site residues in MnaA, which was confirmed through analysis of Q42A, Q69A, E135A and H241A MnaA variants. The kinetic parameters K M and k cat of MnaA were determined to be 3.91 mM and 33.44 s-1 for the forward, and 2.41 mM and 6.02 s-1 for the reverse reaction. While allosteric regulation by UDP-GlcNAc has been proposed as a mechanism for enzyme activation, UDP-GlcNAc was not found to be essential for UDP-ManNAc epimerization by P. alvei MnaA. However, the reaction rate doubled upon addition of 5% UDP-GlcNAc. Unexpectedly, the UDP-GlcNAc analog tunicamycin did not inhibit MnaA. Molecular docking experiments comparing tunicamycin binding of P. alvei MnaA and Staphylococcus aureus MnaA, which is inhibited by tunicamycin, revealed different residues exposed to the antibiotic excluding, those at the predicted allosteric site of P. alvei MnaA, corroborating tunicamycin resistance. The unliganded crystal structure of P. alvei MnaA reveals an open conformation characterized by an accessible cleft between the N- and C-terminal domains. Despite the conservation of residues involved in binding the allosteric activator UDP-GlcNAc, the enzyme is not strictly regulated by the substrate. Unlike S. aureus MnaA, the activity of P. alvei MnaA remains unaffected by tunicamycin.

Biopolymer assisted synthesis of metal–silica hybrid nanoflowers as a medium for the photocatalytic degradation of dye pollutants

This report presents an ecofriendly synthesis and characterization of biopolymer (sodium alginate)-capped silver nanoparticle-silicon dioxide (Ag-SiO2) hybrid nanoflowers and their efficiency for the plasmon-mediated dye degradation of methylene blue. The reducing and capping agents for the initial silver nanoparticles (AgNPs) synthesis were glucose and sodium alginate, respectively. The mesoporous silica nanostructures were introduced using two-step hydrolysis followed by a polycondensation process. Detailed structural and morphological characterizations of the as-prepared hybrid nanostructures were done using various techniques. The results revealed the formation of nanoflower-like hybrid alginate-capped Ag-SiO2 nanostructures with a size range of approximately 523 ± 56 nm. The BET surface area analysis showed that the hybrid nanostructure has a surface area of 15.6 m2/g together with a pore diameter of 18.2 nm. The hybrid Ag-SiO2 nanoflowers showed excellent catalytic properties for the visible light photodegradation of methylene blue dye after 1 min exposure compared to silver nanoparticles at the same condition. The synergistic effect of SiO2 and Ag nanoparticles improved the catalytic property of the hybrid nanostructure. This study demonstrated a simple and effective model for the efficiency of designed hybrid nanostructures for degradation of industrial dyes.

Food packaging Bio-based plastics: Properties, Renewable Biomass resources, Synthesis, and Applications

The current trend in food packaging technology necessitates the development of novel packaging materials in order to extend the shelf life of food and reduce spoliation. To preserve the food product, the construction material of the packaging played a key role.In the emerging field of food packaging technology, using biobased plastics for food packaging shown a comparative advantage.At this moment, bioplastics have shown measurable benefits and are receiving more and more attention from business organizations, political figures, scientific communities, and in the whole public. This was as a result of looking for new plastic profiles brands. Besides, the environmental impact(ecological concerns) of convective materials, the depletion of natural resources specifically the petrochemical, and consumer concerns have necessitated alternative bio-based food packaging items. Therefore, the aim of this study was to review the properties of food packaging materials such as thermal, mechanical, barrier, surface, antimicrobial, optical, and environmental, as well as their synthesis type and applications. The cellulose and starch components of the common agricultural wastes for the synthesis of biopolymers were elaborated. In addition to that, different microalgae species were justified in the manufacturing of bio-based plastics.This review article also included examples of sustainable filler and reinforcement materials used in the food packaging industry. Therefore, this review work contributes to opening up the entire body of scientific knowledge on bio-based plastics used for food packaging and helps to develop important results for further investigation.

The Effect of Concentration of Titanium Dioxide Nanoparticles on Their Antibacterial Activity in the Synthesis of Polyurethane Biopolymers

In the health sector, the use of polyurethane (PU) as a basic material for medical devices still causes problems related to local and systemic infections. One of the most appropriate ways to overcome this problem is to synthesize PU biopolymer with titanium dioxide (TiO2) nanoparticles. The use of nano-shaped materials in this synthesis has many advantages, including being easier to synthesize and being antibacterial. Meanwhile, starch is the result of isolation from banana weevils, where banana weevils are agricultural waste that has not been utilized properly. Particle size and the use of agricultural waste are a form of modification and innovation in PU synthesis, as well as a novelty in the development of this research. In PU synthesis, several characterization techniques are carried out, including polymer tests, namely strain and stress, functional group analysis using (Fourier Transform Infra-Red), and antibacterial tests. Based on the results of the FTIR test analysis, it show that at a wave number of 1724.36 cm-1, the N-H functional group is visible, and the absorption of urethane and TiO2 groups is in the range of 513.07 cm-1. The mechanical properties test shows the strain (28.92 - 21.88% GL) and young's modulus in the interval (5.484-3.268 MPa). The antibacterial test showed that the inhibitory power of test samples A1 and A4 with diameters of 8 mm and 8 mm proved to be very effective in killing E. Coli bacteria, while test samples A1¹, A2¹, A3¹, and A4 were not able to kill E. Coli bacteria. S. Aureus. bacteria. The characterization results show that PU biopolymer can be used as a basic material for making bacterial decontaminant medical devices.

Similarities and differences of nano-sized levan synthesized by Bacillus haynesii at low and high temperatures: Characterization and bioactivity

Levan is a biopolymer with many different uses. Temperature is an important parameter in biopolymer synthesis. Herein, levan production was carried out from Bacillus haynesii, a thermophilic microorganism, in the temperature range of 4 °C-95 °C. The highest levan production was measured as 10.9 g/L at 37 °C. The synthesized samples were characterized by FTIR and NMR analysis. The particle size of the levan samples varied between 153 and 824.4 nm at different temperatures. In levan samples produced at high temperatures, the water absorption capacity is higher in accordance with the particle size. Irregularities were observed in the surface pores at temperatures of 60 °C and above. The highest emulsion capacity of 83.4 % was measured in the sample synthesized at 4 °C. The antioxidant activity of all levan samples synthesized at different temperatures was measured as 84 % on average. All synthesized levan samples showed antibacterial effect on pathogenic bacteria. In addition, levan synthesized at 45 °C showed the highest antimicrobial effect on E. coli ATCC 35218 with an inhibition zone of 21.3 ± 1.82 mm. Antimicrobial activity against yeast sample C. albicans, was measured only in levan samples synthesized at 80 °C, 90 °C, 95 °C temperatures. Levan synthesized from Bacillus haynesii at low and high temperatures showed differences in characterization and bioactivity.

Catecholamine Derivatives as Novel Crosslinkers for the Synthesis of Versatile Biopolymers.

Catecholamine metabolites are not only involved in primary metabolism, but also in secondary metabolism, serving a diverse array of physiologically and biochemically important functions. Melanin, which originates from dopa and dopamine, found in the hair, eye, and skin of all animals, is an important biopolymeric pigment. It provides protection against damaging solar radiation to animals. N-Acetyldopamine and N-β-alanyldopamine play a crucial role in the hardening of the exoskeletons of all insects. In addition, insects and other arthropods utilize the melanogenic process as a key component of their defense systems. Many marine organisms utilize dopyl peptides and proteins as bonding materials to adhere to various substrata. Moreover, the complex dopa derivatives that are precursors to the formation of the exoskeletons of numerous marine organisms also exhibit antibiotic properties. The biochemistry and mechanistic transformations of different catecholamine derivatives to produce various biomaterials with antioxidant, antibiotic, crosslinking, and gluing capabilities are highlighted. These reactivities are exhibited through the transient and highly reactive quinones, quinone methides, and quinone methide imine amide intermediates, as well as chelation to metal ions. A careful consideration of the reactivities summarized in this review will inspire numerous strategies for synthesizing novel biomaterials for future medical and industrial use.

Mitigating biomass recalcitrance for plant‐based bioenergy production

AbstractThe emission of greenhouse gases, particularly carbon dioxide, predominantly from fossil fuel combustion has received critical warnings several times as their levels exceed the tolerable limits in view of global warming. This calls for a paradigm shift from a fossil fuel‐based source to a less hazardous bioenergy source. Plant feedstock is an attractive source of raw materials for bioenergy production; however, chemical or enzymatic digestion of the feedstock is expensive owing to the supramolecular lignocellulosic barrier, indicating the need for better alternatives. Several attempts have been made towards reducing the biomass recalcitrance of straw using genetic transformations. We present a review highlighting potential plant candidates for bioenergy production, the lignocellulose composition of the feedstock, how the composition can impede enzymatic degradation, the regulation of lignocellulose polymer biosynthesis, and the influence of genetic transformation on biomass saccharification. Moreover, the review also discusses conflicting research interests in biomass recalcitrance and suggests a common ground. The review findings suggest that bioenergy production from crop straws will drastically reduce over‐dependence on fossil fuels and consequently pollution levels.

Effect of a dark-colored substrate on the production of phycocyanin by the cyanobacterium Phormidium sp

As the biotechnological production of valuable compounds has recently gathered research interest, more and more photosynthetic microorganisms are being examined for the synthesis of proteins, fatty acids, pigments, and other biopolymers. In this work, a local isolate (lagoons of Western Greece), of the blue-green cyanobacterium Phormidium sp., was evaluated. Its cultures were considered to be promising for the recovery of the phycobiliprotein, called phycocyanin, even during mixotrophic growth. Interestingly, phycocyanin accumulation was favored by substrates with a low organic load. In order to minimize substrate cost, anaerobic digestion effluent was used as a nutrient and organic carbon source, replacing a synthetic medium containing glucose, to meet the cyanobacterium’s nutrient needs. The results from the cultures containing liquid digestate were surprising, as its addition at low concentrations not only allowed Phormidium sp. to grow but also enhanced the phycocyanin synthesis. The experiments that exhibited a notable phycocyanin production showed a final biomass concentration that barely exceeded 0.7 g L−1 regardless of the nature of the substrate. When Phormidium sp. was inoculated in a pure synthetic medium with 1 g L−1 of glucose, phycocyanin concentration approached 10 mg L−1, while it was measured being 1.75 times higher in the culture containing 10% v/v anaerobic effluent, due to greater cellular accumulation. The present work comes as evidence of the successful bioremediation of digestate accompanied by the production of a high added-value pigment, leading to the removal of organic carbon, total nitrogen, and phosphorous in percentages of 60%, 90%, and 40% respectively.

Synthesis and characterization of silk-poly(guluronate) hybrid polymers for the fabrication of dual crosslinked, mechanically dynamic hydrogels

The rapid ionic crosslinking of alginate has been actively studied for biomedical applications including hydrogel scaffolds for tissue engineering, injectable gels, and 3D bioprinting. However, the poor structural stability of ionic crosslinks under physiological conditions limits the widespread applications of these hydrogels. Moreover, the lack of cell adhesion to the material combined with the inability of proteases to degrade alginate further restrict utility as hydrogel scaffolds. Blends of alginate with silk fibroin have been proposed for improved structural and mechanical properties, but potential phase separation between the hydrophobic protein and the hydrophilic polysaccharide remains an issue. In this study, we demonstrated the synthesis of a hybrid biopolymer composed of a silk backbone with side chains of poly(guluronate) isolated from alginate to introduce rapid ionic crosslinking on enzymatically crosslinked silk-based hydrogels for on-demand and reversible stiffening and softening properties. Dual crosslinked macro- and microgels of silk fibroin-poly(guluronate) (SF-PG) hybrid polymers displayed dynamic morphology with reversible shrinking and swelling behavior. SF-PG hydrogel discs demonstrated dynamic mechanics with compressive moduli ranging from less than 5 kPa to over 80 kPa and underwent proteolytic degradation unlike covalently crosslinked alginate controls. SF-PG gels supplemented with gelatin substituted with tyramine or both tyramine and PG also supported the attachment and survival of murine fibroblasts, suggesting potential uses of these new hydrogels in mammalian cell culture to investigate cellular responses to dynamic mechanics or modeling of diseases defined by matrix mechanics, such as fibrosis and cancer.

Synthesis of sustainable sulfur‐containing polycarbonates from xylose and carbonyl sulfide

AbstractHerein, the six‐membered sulfur‐containing cyclic carbonates was successfully synthesized from d‐ and l‐xylose through an environmental friendly process by employing carbonyl sulfide (COS) as a sustainable C1‐carbonation agent. The ring‐opening polymerization of the monomers were rapidly initiated by bifunctional organocatalysts and alkali metal alkoxides, respectively, under ambient reaction conditions. The resultant sulfur‐containing polycarbonates exhibit high‐temperature resistance and good optical properties. This work furnishes an original and practical strategy for utilizing COS as a sulfur feedstock in biopolymer synthesis.

Sustainable one-pot synthesis of novel soluble cellulose-based nonionic biopolymers for natural antimicrobial materials

Novel soluble cellulose-based nonionic biopolymers (CIs) with enhanced antimicrobial properties and nonleachability were successfully produced using a sustainable one-pot synthesis method. Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance H-spectrometer (1H NMR), X-ray Photoelectron Spectroscopy (XPS), and Energy Dispersive Spectroscopy (EDS) results demonstrated that the cellulose (MCC) molecules combined with indole-3-acetic acid (IAA) via esterification to produce CIs with abundant terminal indole groups. The degree of substitution of the prepared CI3 reached 1.85 when the molar ratio of IAA to MCC molecules was 4:1. The prepared CI samples were characterized using X-ray diffractometer (XRD), Scanning Electronic Microscopy (SEM), Thermogravimetric Analysis (TGA), and other analysis techniques. Results indicated that after the MCC was grafted with IAA, its crystallinity decreased and solubility increased. After blending CI3 with polycaprolactone (PCL) to form cellulose-based antimicrobial (PCL–CI) films, the films showed good compatibility, preferable biological cell activity, and low water vapor permeability. When the CI3 content was 10%, the tensile strength of the produced PCL–CI10 film reached 9.96 MPa. Moreover, the prepared PCL–CI films exhibited good nonleachability after being immersed in water for 5 d. The disk diffusion assay revealed that the CIs and PCL–CI films had good antimicrobial and bactericidal effects against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The minimal inhibitory concentration was 5 μg disk−1, significantly lower than that of traditional antibiotics and chitosan. The nonionic biopolymers are simple and efficient to prepare and ecofriendly as well as exhibit nontoxicity, good solubility, enhanced antimicrobial properties, and nonleachability, which can provide new ideas for developing natural biomass-based nonionic antimicrobial materials with potential applications in wound dressing, medical devices, and food packaging.

Stochastic modelling of a three-dimensional glycogen granule synthesis and impact of the branching enzyme.

In humans, glycogen storage diseases result from metabolic inborn errors, and can lead to severe phenotypes and lethal conditions. Besides these rare diseases, glycogen is also associated to widely spread societal burdens such as diabetes. Glycogen is a branched glucose polymer synthesised and degraded by a complex set of enzymes. Over the past 50 years, the structure of glycogen has been intensively investigated. Yet, the interplay between the detailed three-dimensional glycogen structure and the related enzyme activity is only partially characterised and still to be fully understood. In this article, we develop a stochastic coarse-grained and spatially resolved model of branched polymer biosynthesis following a Gillespie algorithm. Our study largely focusses on the role of the branching enzyme, and first investigates the properties of the model with generic parameter values, before comparing it to in vivo experimental data in mice. It arises that the ratio of glycogen synthase over branching enzyme reaction rates drastically impacts the structure of the granule. We deeply investigate the mechanism of branching and parametrise it using distinct lengths. Not only do we consider various possible sets of values for these lengths, but also distinct rules to apply them. We show how combining various values for these lengths finely tunes glycogen macromolecular structure. Comparing the model with experimental data confirms that we can accurately reproduce glycogen chain length distributions in wild type mice. Additional granule properties obtained for this fit are also in good agreement with typically reported values in the experimental literature. Nonetheless, we find that the mechanism of branching must be more flexible than usually reported. Overall, our model provides a theoretical basis to quantify the effect that single enzymatic parameters, in particular of the branching enzyme, have on the chain length distribution. Our generic model and methods can be applied to any glycogen data set, and could in particular contribute to characterise the mechanisms responsible for glycogen storage disorders.

Radiation synthesis and modification of biopolymers and polymeric composites for biomedical applications

Recently the replacing of the petrochemical origin polymers with biopolymers and biocomposites which are environmental biodegradable polymers became a growing interest. The use of gamma radiation for synthesis and produce further modification of the biopolymers and biocomposites found to be suitable for biomedical application due to none using of toxic additives. Moreover, the radiation technique is the combining of preparation and sterilization in a one technological step thus, reducing time of the production and lower the costs. The use of gamma radiation technique in biomedical application is growing rapidly in controlled drug delivery, injectable materials, wound dressing, tissue engineering, immobilized enzymes and biosensors.

Sulfonic Acid‐Functionalized (Bio)Materials as Catalysts for Efficient Amide Bond Synthesis

AbstractSulfonic acid carbon‐(bio)based and natural clays‐based catalysts were prepared and investigated for the first time as heterogeneous catalysts for amide bond synthesis by a Ritter reaction. The different SO3H‐catalysts were screened using benzyl alcohol and acetonitrile as model substrates, and MWCNT‐CSP revealed to be an efficient catalyst, affording the amide in 75 % yield. The practical utility of the catalysts was demonstrated by a diverse range of amides, obtained from alcohols and nitriles, in moderate to good yields. Biomass derived platform alcohols, such as 5‐HMF and furfuryl alcohol, were also tested as potential building blocks for the synthesis of biopolymers. The SO3H‐catalysts revealed to be a highly efficient and environmentally friendly alternative to the conventional acid catalysts commonly used in the Ritter reaction.

One-Step Oxidation of Orange Peel Waste to Carbon Feedstock for Bacterial Production of Polyhydroxybutyrate.

Orange peels are an abundant food waste stream that can be converted into useful products, such as polyhydroxyalkanoates (PHAs). Limonene, however, is a key barrier to building a successful biopolymer synthesis from orange peels as it inhibits microbial growth. We designed a one-pot oxidation system that releases the sugars from orange peels while eliminating limonene through superoxide (O2• -) generated from potassium superoxide (KO2). The optimum conditions were found to be treatment with 0.05 M KO2 for 1 h, where 55% of the sugars present in orange peels were released and recovered. The orange peel sugars were then used, directly, as a carbon source for polyhydroxybutyrate (PHB) production by engineered Escherichia coli. Cell growth was improved in the presence of the orange peel liquor with 3 w/v% exhibiting 90-100% cell viability. The bacterial production of PHB using orange peel liquor led to 1.7-3.0 g/L cell dry weight and 136-393 mg (8-13 w/w%) ultra-high molecular weight PHB content (Mw of ~1900 kDa) during a 24 to 96 h fermentation period. The comprehensive thermal characterization of the isolated PHBs revealed polymeric properties similar to PHBs resulting from pure glucose or fructose. Our one-pot oxidation process for liberating sugars and eliminating inhibitory compounds is an efficient and easy method to release sugars from orange peels and eliminate limonene, or residual limonene post limonene extraction, and shows great promise for extracting sugars from other complex biomass materials.

In Situ Polymerization of Aniline Derivative in Vivo for NIR-II Phototheranostics of Tumor.

Natural biopolymers can be controllably in situ synthesized in organisms and play important roles in biological activities. Inspired by this, the manipulation of in situ biosynthesis of functional polymers in vivo will be an important way to obtain materials for meeting biological requirements. Herein, in situ biosynthesis of functional conjugated polymer at the tumor site was achieved via the utilization of specific tumor microenvironment (TME) characteristics for the first time. Specially, a water-soluble aniline dimer derivative (N-(3-sulfopropyl) p-aminodiphenylamine, SPA) was artfully in situ polymerized into polySPA (PSPA) nanoparticles at the tumor site, which was activated via the catalysis of hydrogen peroxide (H2O2) overexpressed in TME to produce hydroxyl radical (•OH) by coinjected horseradish peroxidase (HRP). Benefiting from outstanding near-infrared (NIR)-II absorption of PSPA, the in situ polymerization process can be validly monitored by photoacoustic (PA) signal at the NIR-II region. Meanwhile, in situ polymerization would induce the size of polymeric materials from small to large, improving the distribution and retention of PSPA at the tumor site. On the combination of NIR-II absorption of PSPA and the size variation induced by polymerization, such polymerization can be applied for tumor-specific NIR-II light mediated PA image and photothermal inhibition of tumors, enhancing the precision and efficacy of tumor phototheranostics. Therefore, the present work opens the way to manipulate TME-activated in situ biosynthesis of functional conjugated polymer at the tumor site for overcoming formidable challenges in tumor theranostics.

Perspectives on development of biomedical polymer materials in artificial intelligence age.

Polymer materials are widely used in biomedicine, chemistry and material science, whose traditional preparations are mainly based on experience, intuition and conceptual insight, having been applied to the development of many new materials, but facing great challenges due to the vast design space for biomedical polymers. So far, the best way to solve these problems is to accelerate material design through artificial intelligence, especially machine learning. Herein, this paper will introduce several successful cases, and analyze the latest progress of machine learning in the field of biomedical polymers, then discuss the opportunities of this novel method. In particular, this paper summarizes the material database, open-source determination tools, molecular generation methods and machine learning models that have been used for biopolymer synthesis and property prediction. Overall, machine learning could be more effectively deployed on the material design of biomedical polymers, and it is expected to become an extensive driving force to meet the huge demand for customized designs.