Hydrophilic Copolymers Research Articles

Polymorphic Supramolecular Therapeutic Platforms with Precise Dye/Drug Ratio to Perform Synergistic Chemo-Photo Anti-Tumor Therapy and Long-Term Immune Protection.

Malignant tumor has become one of the hellish killers threatening the health of people around the world, its diagnosis and treatment has become the concerns of public. However, the optimal therapeutic dose, undesired side-effect, and long-term immune activation werekey and bottleneck problems in tumor treatment. Herein, different batches of supramolecular therapeutic platforms, including vesicles, spherical nanoparticles, and cylindrical nanorods, with precise ratios of dye to drug (1:2) and multiple stimulus responsiveness wereconstructed by host-guest complexation between cyanine-camptothecin conjugates (IR780-CPT2) and β-cyclodextrin (β-CD) pendent hydrophilic copolymers. The reduction responsiveness, near-infrared photothermal conversion and singlet oxygen (1O2) generation performances endowed these platforms excellent cancer cells killing effect in both of in vitro cellular experiments and in vivo mice models. More importantly, without affecting the weight of mice, the maturation of dendritic cells, proliferation of T cells, up-regulation of high mobility group protein B1, and reduction of immunosuppressive regulatory T cells weredetected after employing a synergistic chemo-photo therapy, demonstrating the body's immune effect was successfully activated. Thus, during the treatment of primary tumor, the distal tumor was also inhibited. Webelieve this work could provide a distinctive way to fabricate supramolecular theranostic platforms with different morphologies and improve antitumor and antimetastasis capabilities.

Hydrophilicity modification of polyphenylene sulfide: A comparative study on the introduction of Zr by physical blending and copolymerization

Polyphenylene sulfide (PPS) is widely used in auto components, machinery parts, electrical accessories, and anti-corrosion coatings, but its hydrophobicity restricts its application in biomaterials, medical equipment, battery separators, and oil pollution separation membranes. To improve the hydrophilicity of PPS, zirconium oxynitrate reacted with 3,5-dichlorosalicylic acid (SA) to generate zirconium-carboxylate (ZrSA). ZrSA was then incorporated into the main chain of PPS through copolymerization to yield hydrophilic copolymers (ZrSA-PPS). Meanwhile, SA was copolymerized into the main chain of the PPS to produce SA-PPS. Next, SA-PPS and ZrO2 were physically blended to obtain hydrophilic composites (ZrO2/SA-PPS). The melting point of ZrSA-PPS ranged from 278.19 to 281.16 °C, which was slightly higher than that of ZrO2/SA-PPS (278.39–279.95 °C), but its crystallinity (34.3–41.2 %) was lower than that of ZrO2/SA-PPS (42.2–51.6 %). The maximum decomposition temperatures of ZrSA-PPS and ZrO2/SA-PPS were increased by about 10 °C, indicating that the Zr–O bonds obstruct the thermally induced movements of the molecular chain. The ZrSA-PPS possessed a tensile strength of 40.8–70.5 MPa and a flexural strength of 46.4–103.4 MPa. The tensile and flexural strengths of ZrO2/SA-PPS (14.6–65.1 Mpa and 23.1–100.3 Mpa) were significantly inferior to that of ZrSA-PPS. This revealed that the ZrSA cross-linked structure can prevent crack propagation. The water contact angle of ZrSA-PPS and ZrO2/SA-PPS were ranged from 59.0° to 76.5° and 61.6°–78.5° (Neat-PPS, ∼87.9°), respectively. The agglomeration of ZrO2 resulted in a slightly higher water contact angle for ZrO2/SA-PPS than for ZrSA-PPS. The enhanced hydrophilicity of ZrSA-PPS benefited from the formation of large chain spacing, strong polar groups, and hydrogen bonds. Our study may shed light on the hydrophilic modification of PPS, which should offer a valuable guide and option for PPS in hydrophilic applications.

Thermoresponsive behavior of dual hydrophilic diblock copolymers prepared via organotellurium-mediated living radical polymerization

Thermoresponsive behavior of dual hydrophilic diblock copolymers prepared via organotellurium-mediated living radical polymerization

Hydrogels and Aerogels for Versatile Photo-/Electro-Chemical and Energy-Related Applications.

The development of photo-/electro-chemical and flexible electronics has stimulated research in catalysis, informatics, biomedicine, energy conversion, and storage applications. Gels (e.g., aerogel, hydrogel) comprise a range of polymers with three-dimensional (3D) network structures, where hydrophilic polyacrylamide, polyvinyl alcohol, copolymers, and hydroxides are the most widely studied for hydrogels, whereas 3D graphene, carbon, organic, and inorganic networks are widely studied for aerogels. Encapsulation of functional species with hydrogel building blocks can modify the optoelectronic, physicochemical, and mechanical properties. In addition, aerogels are a set of nanoporous or microporous 3D networks that bridge the macro- and nano-world. Different architectures modulate properties and have been adopted as a backbone substrate, enriching active sites and surface areas for photo-/electro-chemical energy conversion and storage applications. Fabrication via sol-gel processes, module assembly, and template routes have responded to professionalized features and enhanced performance. This review presents the most studied hydrogel materials, the classification of aerogel materials, and their applications in flexible sensors, batteries, supercapacitors, catalysis, biomedical, thermal insulation, etc.

Impact of the Hydrophilicity of Poly(sarcosine) on Poly(ethylene glycol) (PEG) for the Suppression of Anti-PEG Antibody Binding.

A method of poly(ethylene glycol) (PEG) conjugation is known as PEGylation, which has been employed to deliver therapeutic drugs, proteins, or nanoparticles by considering the intrinsic non- or very low immunogenic property of PEG. However, PEG has its weaknesses, and one major concern is the potential immunogenicity of PEGylated proteins. Because of its hydrophilicity, poly(sarcosine) (P(Sar)) may be an attractive-and superior-substitute for PEG. In the present study, we designed a double hydrophilic diblock copolymer, methoxy-PEG-b-P(Sar) m (m = 5-55) (mPEG-P(Sar) m ), and synthesized a triblock copolymer with hydrophobic poly(l-isoleucine) (P(Ile)). We validated that double hydrophilic mPEG-P(Sar) block copolymers suppressed the specific binding of three monoclonal anti-PEG antibodies (anti-PEG mAbs) to PEG. The results of our indirect ELISAs indicate that P(Sar) significantly helps to reduce the binding of anti-PEG mAbs to PEG. Importantly, the steady suppression of this binding was made possible, in part, thanks to the maximum number of sarcosine units in the triblock copolymer, as evidenced by sandwich ELISA and biolayer interferometry assay (BLI): the intrinsic hydrophilicity of P(Sar) had a clear supportive effect on PEG. Finally, because we used P(Ile) as a hydrophobic block, PEG-P(Sar) might be an attractive alternative to PEG in the search for protein shields that minimize the immunogenicity of PEGylated proteins.

Preparation of Water-Soluble Polyion Complex (PIC) Micelles with pH-Responsive Carboxybetaine Block.

A dual zwitterionic diblock copolymer (M100C100) consisting of poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC, M) and poly(3-((2-(methacryloyloxy)ethyl) dimethylammonio) propionate) (PCBMA, C) is synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. A double hydrophilic diblock copolymer (M100S100) consist of PMPC and anionic poly(3-sulfopropyl methacrylate potassium salt) (PMPS, S) is synthesized via RAFT. The degrees of polymerization of each block are 100. The charges of PMPC are neutralized intramolecularly. At neutral pH, the charges in PCBMA are also neutralized intramolecularly due to its carboxybetaine structure. Under acidic conditions, PCBMA exhibits polycation behavior as the pendant carboxy groups become protonated, forming cationic tertiary amine groups. PMPS shows permanent anionic nature independent of pH. Charge neutralized mixture of cationic M100C100 and anionic M100S100 in acidic aqueous solution forms water-soluble polyion complex (PIC) micelle owing to electrostatic attractive interactions. The core is composed of the cationic PCBMA and anionic PMPS blocks, with the PMPC blocks serving as shells that covered the core surface, forming spherical core-shell PIC micelles. Above pH 4 the pendant carboxy groups in PCBMA undergo deprotonation, transitioning to a zwitterionic state, thereby eliminating the cationic charge in PCBMA. Therefore, above pH 4 the PIC micelles are dissociated due to the disappearance of the charge interactions.

Forming Single-Cell-Derived Colon Cancer Organoid Arrays on a Microfluidic Chip for High Throughput Tumor Heterogeneity Analysis.

Single-cell-derived tumor organoids (STOs) possess a distinct genetic background, making them valuable tools for demonstrating tumor heterogeneity. In order to fulfill the high throughput demands of STO assays, we have developed a microfluidic chip containing 30 000 microwells, which is dedicated to a single cell culture approach for selective expansion and differential induction of cancer stem cells. The microwells are coated with a hydrophilic copolymer to eliminate cell adhesion, and the cell culture is supported by poly(ethylene glycol) (PEG) to establish a nonadhesive culture environment. By utilizing an input cell density of 7 × 103·mL-1, it is possible to construct a 4000 single cell culture system through stochastic cell occupation. We demonstrate that the addition of 15% PEG10000 in the cell culture medium effectively prevents cell loss while facilitating tumor stem cell expansion. As were demonstrated by HCT116, HT29, and SW480 colon cancer cells, the microfluidic approach achieved a STO formation rate of ∼20%, resulting in over 800 STOs generated from a single culture. Comprehensive analysis through histomorphology, immunohistochemistry, drug response evaluation, assessment of cell invasion, and biomarker detection reveals the heterogeneity among individual STOs. Specifically, the smaller STOs exhibited higher invasion and drug resistance capabilities compared with the larger ones. The developed microfluidic approach effectively facilitates STO formation and offers promising prospects for investigating tumor heterogeneity, as well as conducting personalized therapy-focused drug screening.

How Polyoxometalate Promote the Aggregation of a Cyanine Dye in the Aqueous Solution of Non-Ionic Copolymers of Varying Hydrophilic-Lipophilic Balance?

The nonradiative pathway leading to the photoisomerization of a cyanine dye is well-established information. However, the modulations induced in the photoisomerization pathway by a Keggin-type polyoxometalate in a confined media is new. Our study reveals that, in the presence of pluronic block copolymers F-108 and P-123, phosphomolybdic acid hydrate (PMA) promotes the aggregation of 3,3'-diethylthiadicarbocyanine iodide (DTDCI). The absorption spectra show a clear indication of a red-shifted trimer band in F-108 and P-123, whereas it is absent in F-127 and P-84. Fluorescence emission studies suggest that, in the presence of PMA, the rate of photoisomerization is accelerated in F-108, P-123, and P-84 micelles, whereas it is retarded in F-127 micelles. Time-resolved studies in the presence of PMA indicate the preference of F-108, P-84, and P-123 toward the trapped conformer of DTDCI, whereas F-127 favors the formation of photoisomer of DTDCI. Our findings imply the importance of the interplay between the hydrophobic and electrostatic interactions between the DTDCI cations and the PMA anions in nonionic micelles of varying hydrophilic-lipophilic balance (HLB). Dynamic light scattering (DLS) data suggest a modulation by PMA in the intermicellar electrostatic repulsions of a hydrophilic copolymer micelle, whereas its unaffected in a hydrophobic copolymeric micelle.

Responsive Acrylamide-Based Hydrogels: Advances in Interpenetrating Polymer Structures.

Hydrogels, composed of hydrophilic homopolymer or copolymer networks, have structures similar to natural living tissues, making them ideal for applications in drug delivery, tissue engineering, and biosensors. Since Wichterle and Lim first synthesized hydrogels in 1960, extensive research has led to various types with unique features. Responsive hydrogels, which undergo reversible structural changes when exposed to stimuli like temperature, pH, or specific molecules, are particularly promising. Temperature-sensitive hydrogels, which mimic biological processes, are the most studied, with poly(N-isopropylacrylamide) (PNIPAm) being prominent due to its lower critical solution temperature of around 32 °C. Additionally, pH-responsive hydrogels, composed of polyelectrolytes, change their structure in response to pH variations. Despite their potential, conventional hydrogels often lack mechanical strength. The double-network (DN) hydrogel approach, introduced by Gong in 2003, significantly enhanced mechanical properties, leading to innovations like shape-deformable DN hydrogels, organic/inorganic composites, and flexible display devices. These advancements highlight the potential of hydrogels in diverse fields requiring precise and adaptable material performance. In this review, we focus on advancements in the field of responsive acrylamide-based hydrogels with IPN structures, emphasizing the recent research on DN hydrogels.

Molecular design of antifouling ultrafiltration membranes via copolymerization of bactericidal and hydrophilic polymers

Membrane fouling is still a significant obstacle to applying polyvinylidene fluoride (PVDF) ultrafiltration membranes. We developed bactericidal and hydrophilic comb copolymers to address this issue by introducing quaternary ammonium compounds (QAC) and sulfobetaine methacrylate (SBMA) onto PVDF powder. Utilizing atom transfer radical polymerization, we synthesized a series of polymer brushes by adjusting the QAC and SBMA functional monomers ratio. These polymer brushes were then employed to fabricate modified membranes featuring diverse alkyl chain lengths and hydrophilic layers. All modified membranes exhibited antibacterial and anti-adhesion properties. Increasing the SBMA monomer ratio resulted in reduced membrane pore size, a smoother membrane surface, and enhanced hydrophilicity. This balanced approach synergistically integrates “defensive” and “offensive” strategies, adjusting polymer proportions to confer dual functionality of hydrophilicity and bactericidal action in ultrafiltration membranes. Notably, the functionalized PVDF powder with copolymer chains exhibited a high inhibition efficiency of 100% against E. coli and 52.0% against E. faecalis, and the optimized membranes have an impressive performance of effectively preventing bacteria adhesion and inactivating attached bacteria. Dynamic filtration experiments further revealed the superior anti-biofouling capabilities of the modified membrane. Furthermore, the membrane containing 50% SBMA and 50% QAC exhibited a 69.5% improvement in anti-organic performance compared to those with only QAC. Our study presents a straightforward and efficient approach for designing antifouling PVDF membranes, showing great promise for wastewater treatment applications.

In Situ Preparation of Star-Shaped Protein-"Smart" Polymer Conjugates with pH and Thermo-Dual Responsibility for Bacterial Separation.

To achieve effective separation and enrichment of bacteria, a novel synthetic scheme was developed to synthesize star-style boronate-functionalized copolymers with excellent hydrophilicity and temperature and pH responsiveness. A hydrophilic copolymer brush was synthesized by combining surface-initiated atom-transfer radical polymerization with amide reaction using bovine serum albumin as the core. The copolymer brush was further modified by introducing and immobilizing fluorophenylboronic acids through an amide reaction, resulting in the formation of boronate affinity material BSA@poly(NIPAm-co-AGE)@DFFPBA. The morphology and organic content of BSA@poly(NIPAm-co-AGE)@DFFPBA were systematically characterized. The BSA-derived composites demonstrated a strong binding capacity to both Gram-positive and Gram-negative bacteria. The binding capabilities of the affinity composite to Staphylococcus aureus and Salmonella spp. were 195.8 × 1010 CFU/g and 79.2 × 1010 CFU/g, respectively, which indicates that the novel composite exhibits a high binding capability to bacteria and shows a particularly more significant binding capacity toward Gram-positive bacteria. The bacterial binding of BSA@poly(NIPAm-co-AGE)@DFFPBA can be effectively altered by adjusting the pH and temperature. This study demonstrated that the star-shaped affinity composite had the potential to serve as an affinity material for the rapid separation and enrichment of bacteria in complex samples.

Customizing Cerium Oxide Particle Synthesis with Hybrid Polyion Complex Templates for Enhanced Oxidation Performance in Photo-Fenton Processes.

Hybrid poly-ion complexes were synthesized through the complexation of a double hydrophilic copolymer with Ce(III) ions. These colloids act as reservoirs for cerium ions, enabling the synthesis of cerium-based Prussian blue nanoparticles with a cubic structure, a narrow size distribution around 100 nm, and good colloidal stability in water. Upon high-temperature calcination, these nanoparticles are transformed into a cerium/iron-based metal oxide catalyst (CeO2/Fe2O3). The resultant composite catalyst demonstrates superior performance in the photo-Fenton oxidation of methylene blue pollutants, achieving a conversion efficiency that rivals other metal-based oxides and cerium-based catalysts.

Closely Packed Core-Shell Micelle Structures of Double Hydrophilic Miktoarm Star Copolymers at the Air-Water Interface.

The aggregation behavior of amphiphilic block copolymers at the air-water interface has been extensively studied, but less attention was given to that of star copolymers. In this work, we studied the interfacial aggregation behavior of two double hydrophilic pH- and temperature-responsive miktoarm star copolymers of poly[di(ethylene glycol) methyl ether methacrylate]-poly[2-(dimethylamino)ethyl methacrylate] (PDEGMA3-PDMAEMA3 and PDEGMA4-PDMAEMA7, the subscripts denote arm numbers) with different molecular weights. The effects of subphase pH and temperature on the monolayer isotherms and hysteresis curves of the two star copolymers and the morphologies of their Langmuir-Blodgett (LB) films were studied by the Langmuir film balance technique and atomic force microscopy, respectively. At the air-water interface, the two star copolymers tend to form closely packed micelles. These micelles exhibit a core-shell structure, where the small hydrophobic core consists of cross-linker of ethylene glycol dimethacrylate (EGDMA) and the carbon backbones of PDEGMA and PDMAEMA arms and the short hydrophilic shell is composed of di(ethylene glycol) and tertiary amine side groups. With increasing subphase pH, the surface pressure versus molecular area isotherms shift toward larger mean molecular areas as a result of the enhanced interface adsorption of nonprotonated tertiary amine groups. The isotherm shift of PDEGMA3-PDMAEMA3 monolayers is primarily attributed to high density of tertiary amine groups in the shells, while that of PDEGMA4-PDMAEMA7 is mainly attributed to high density of di(ethylene glycol) groups in the shells. The hysteresis degrees in the monolayers of the two copolymers under alkaline and neutral conditions are greater than those under acidic conditions due to the decreased protonation degree of the tertiary amine groups. At 10 °C, the mobility of the shells is poor and the isotherms are located on the right. Above the lower critical solution temperature, di(ethylene glycol) groups contract, which causes a slight shift of the isotherms toward smaller mean molecular areas.

Nanogel-type nano-objects from a random polyelectrolyte through intermolecular cross-linking

Polyelectrolyte nanogel-like nano-objects were synthesized from poly((2-dimethylamino) ethyl methacrylate-co-oligoethylene glycol methacrylate), P(DMAEMA-co-OEGMA), random copolymers through covalent cross-linking with the hydrophobic 1,12-dibromododecane difunctional quaternizing agent, with varying degrees of cross-linking, corresponding to different dimethylamino group molar conversions to quaternized, permanently cationic amino groups. Physicochemical characterization, employing dynamic and electrophoretic light scattering (DLS, ELS), along with fluorescence spectroscopy (FS) measurements under various solution conditions elucidated distinct self-assembled structures of the formed polymer networks, most probably due to the utilization of the hydrophilic random copolymers as precursor macromolecules. The nanogels demonstrated pH responsiveness and temperature sensitivity, advantageous for applications requiring controlled release or environmental adaptability, while the stability under high ionic strength conditions indicated their resilience in complex physiological environments and varying salinities. Furthermore, Nanogel 2, displaying a balanced response to environmental factors, was successfully complexed with protein ovalbumin (OVA). The produced OVA/Nanogel 2 complexes maintained their size under high salt concentrations and sustained colloidal stability over time, even under ultrasound exposure. Further characterization through Cryo-TEM and ATR-FTIR spectroscopy highlighted the efficient complexation of OVA, revealing varying co-assembled structures, including irregular nano-objects consisting of thread-like structures and sphere-like morphologies comprised of branched-like internal structures, dependent on the protein concentration. We expect that such hybrid nanostructures may be promising for enzyme immobilization and as vaccine-delivering vehicles with special morphologies.

Highly hydrophilic methacrylamide-based copolymers as precursors for polymeric nanomedicines containing anthracyclines

The crucial limitation of most low molecular weight cytostatic drugs, including anthracyclines, is their nonspecific biodistribution causing severe adverse effects during cancer treatment. Recently, nanomedicines such as polymer-based systems have been developed as advanced drug delivery systems. Herein, we report the design, synthesis, and characterization of highly water-soluble polymer-carriers based on N‑(1,3‑dihydroxyprop-2-yl)methacrylamide (DHPMA). Polymers differing in molecular weight, hydrodynamic size, and dispersity were synthesized via free or controlled radical polymerization and conjugated to an anthracycline drug pirarubicin (THP) via a pH-sensitive hydrazone bond achieving up to 21 wt% of THP. The DHPMA copolymers were extensively compared to the well-known drug delivery vectors, N-(2-hydroxypropyl)methacrylamide (HPMA)-based copolymers. Importantly, DHPMA-based conjugates showed excellent hydrophilicity exceeding that of HPMA-based copolymers and did not aggregate even after loading with THP reaching 21 wt%. The DHPMA-based polymer nanomedicines exhibited excellent cytotoxicity, body biodistribution, tumor accumulation, and antitumor efficacy, significantly reducing the side effects and toxicity comparable to HPMA-based systems, thus demonstrating their applicability and suitability as efficient drug carriers.

Aqueous degradability of water-soluble, thioester-containing polyacrylamides with UCST-type behaviour in salt solutions obtained by rROP.

We report the successful synthesis of hydrophilic thioester-containing polyacrylamide copolymers by the RAFT and free-radical copolymerisation of dibenzo[c,e]oxepane-5-thione with either acrylamide or N-isopropylacrylamide. These copolymers efficiently degrade in aqueous solutions of sodium hydroxide, isopropylamine, L-cysteine, and household bleach, reducing the weight-average molecular weight by up to ∼90%.

Single-Component Hydrophilic Terpolymer Thin Film Systems for Imparting Surface Chemical Versatility on Various Substrates.

We demonstrate a single-component hydrophilic photocrosslinkable copolymer system that incorporates all critical functionalities into one chain. This design allows for the creation of uniform functional organic coatings on a variety of substrates. The copolymers were composed of a poly(ethylene oxide)-containing monomer, a monomer that can release a primary amine upon UV light, and a monomer with reactive epoxide or cyclic dithiocarbonate with a primary amine. These copolymers are easily incorporated into the solution-casting process using polar solvents. Furthermore, the resulting coating can be readily stabilized through UV light-induced crosslinking, providing an advantage for controlling the surface properties of various substrates. The photocrosslinking capability further enables us to photolithographically define stable polymer domains in a desirable region. The resulting copolymer coatings were chemically versatile in immobilizing complex molecules by (i) post-crosslinking functionalization with the reactive groups on the surface and (ii) the formation of a composite coating by mixing varying amounts of a protein of interest, i.e., fish skin gelatin, which can form a uniform dual crosslinked network. The number of functionalization sites in a thin film could be controlled by tuning the composition of the copolymers. In photocrosslinking and subsequent functionalizations, we assessed the reactivity of the epoxide and cyclic dithiocarbonate with the generated primary amine. Moreover, the orthogonality of the possible reactions of the presented reactive functionalities in the crosslinked thin films with complex molecules is assessed. The resulting copolymer coatings were further utilized to define a hydrophobic surface or an active surface for the adhesion of biological objects.

Breaking the hydrophilic limitation of polyphenylene sulfide through the introduction of bulky polar monomers

Polyphenylene sulfide (PPS) is widely used in electrical accessories, instrument parts, dust filter materials, and separation membranes, but its hydrophobicity restricts its applications, especially in biomaterials and medical devices. To endow PPS with hydrophilicity from molecular structure, here a strategy is proposed of linking bulky polar monomers to the main chain of the PPS by copolymerization. Although the polarity and bulkiness of the monomers can collaboratively promote the hydrophilicity of PPS, they have opposite effects on improving the thermal properties of PPS. Meanwhile, these monomers did not alter the semi-crystalline nature of PPS. The synthesized PPS copolymers have water contact angles ranging from 68 to 86° (Neat-PPS, ∼100°). The greater the polarity and bulkiness of the monomers, the lower the water contact angle of the copolymers. Moreover, the best hydrophilic copolymer combines structural stability and cytocompatibility. Importantly, it is more conducive to cell adhesion than Neat-PPS. The improved hydrophilicity of PPS copolymers can be harvested for bone scaffold materials and broaden the application of PPS in bone biomaterials.

Starch-based hydrogels: current status and applications in food

Hydrogel is a gel formed by a three-dimensional network of hydrophilic polymers and copolymers, widely used for different purposes in the textile, pharmaceutical, cosmetic, biomedical, and food industries. The use of starch hydrogels in food applications is growing and can be used mainly as a release control system for bioactive compounds, ingredient for 3D printing of food and in bioactive films. This integrative review aimed to bring the current scenario of the development of starch-based hydrogels and their use in the food area. Studies published from 2011 to 2021, available in full, published in Portuguese, English or Spanish, were selected. 631 studies were found in the searched databases. Of these, 599 were excluded and 32 selected. Studies have revealed that the development of starch hydrogels has increased more and more, being widely discussed nowadays, with relevance for application in the food area.

Dense Monolayer Network Structures of Double Hydrophilic Hyperbranched Copolymers at the Air/Water Interface.

Influences of subphase pH and temperature on the interfacial aggregation behavior of two double hydrophilic hyperbranched copolymers of poly[oligo(ethylene glycol) methacrylate-co-(2-diisopropylamino)ethyl methacrylate] (P(OEGMA-co-DIPAEMA)) at the air/water interface are studied by the Langmuir film balance technique. Morphologies of their Langmuir-Blodgett (LB) films are characterized by atomic force microscopy (AFM). At the interface, P(OEGMA-co-DIPAEMA) copolymers tend to form a dense network structure of circular micelles composed of branching agent-connected carbon backbone cores and mixed shells of OEGMA and DIPAEMA segments (pendant groups). This network structure containing many honeycomb-like holes with diameters of 6-8nm is identified for the first time and clearly observed in the enlarged AFM images of their LB films. Under acidic conditions, surface pressure versus molecular area isotherms of the two copolymers in the low-pressure region show larger mean molecular area than those under neutral and alkaline conditions due to the lack of impediment from DIPAEMA segments. Upon further compression, each isotherm exhibits a wide pseudo-plateau, which corresponds to OEGMA segments being pressed into the subphase. Furthermore, the isotherms under neutral and alkaline conditions exhibit the lower critical solution temperature behavior of OEGMA segments, and the critical temperature is lower when the hyperbranched copolymer contains higher OEGMA content.