Sugar-Breathing Glycopolymersomes for Regulating Glucose Level

Advancing Artificial Cells with Functional Compartmentalized Polymeric Systems - In Honor of Wolfgang Meier

The fundamental building block of living organisms is the cell, which is the universal biological base of all living entities. This micrometric mass of cytoplasm and the membrane border have fascinated scientists due to the highly complex and multicompartmentalized structure. This specific organization enables numerous metabolic reactions to occur simultaneously and in segregated spaces, without disturbing each other, but with a promotion of inter- and intracellular communication of biomolecules. At present, artificial nano- and microcompartments, whether as single components or self-organized in multicompartment architectures, hold significant value in the study of life development and advanced functional materials and in the fabrication of molecular devices for medical applications. These artificial compartments also possess the properties to encapsulate, protect, and control the release of bio(macro)molecules through selective transport processes, and they are capable of embedding or being connected with other types of compartments. The self-assembly mechanism of specific synthetic compartments and thus the fabrication of a simulated organelle membrane are some of the major aspects to gain insight. Considerable efforts have now been devoted to design various nano- and microcompartments and understand their functionality for precise control over properties. Of particular interest is the use of polymeric vesicles for communication in synthetic cells and colloidal systems to reinitiate chemical and biological communication and thus close the gap toward biological functions. Multicompartment systems can now be effectively created with a high level of hierarchical control. In this way, these structures can not only be explored to deepen our understanding of the functional organization of living cells, but also pave the way for many more exciting developments in the biomedical field.

A glycopolymersome strategy for 'drug-free' treatment of diabetic nephropathy

Diabetic nephropathy is a severe complication of diabetes. Treatment of diabetic nephropathy is an important challenge due to persistent hyperglycemia and elevated levels of reactive oxygen species (ROS) in the kidney. Herein, we designed a glycopolymersome that can treat type 2 diabetic nephropathy by effectively inhibiting hyperglycemia and ROS-associated diabetic nephropathy pathogenesis. The glycopolymersome is self-assembled from phenylboronic acid derivative-containing copolymer, poly(ethylene oxide)45-block-poly[(aspartic acid)13-stat-glucosamine24-stat-(phenylboronic acid)18-stat-(phenylboronic acid pinacol ester)3] [PEO45-b-P(Asp13-stat-GA24-stat-PBA18-stat-PAPE3)]. PBA segment can reversibly bind blood glucose or GA segment for long-term regulation of blood glucose levels; PAPE segment can scavenge excessive ROS for renoprotection. In vitro studies confirmed that the glycopolymersomes exhibit efficient blood glucose responsiveness within 2 h and satisfactory ROS-scavenging ability with 500 μM H2O2. Moreover, the glycopolymersomes display long-acting regulation of blood glucose levels in type 2 diabetic nephropathy mice within 32 h. Dihydroethidium staining revealed that these glycopolymersomes reduced ROS to normal levels in the kidney, which led to 61.7% and 76.6% reduction in creatinine and urea levels, respectively, along with suppressing renal apoptosis, collagen accumulation, and glycogen deposition in type 2 diabetic nephropathy mice. Notably, the polypeptide-based glycopolymersome was synthesized by ring-opening polymerization (ROP) of N-carboxyanhydrides (NCAs), thereby exhibiting favorable biodegradability. Overall, we proposed a new glycopolymersome strategy for 'drug-free' treatment of diabetic nephropathy, which could be extended to encompass the design of various multifunctional nanoparticles targeting diabetes and its associated complications.

Capturing Enzyme-Loaded Diblock Copolymer Vesicles Using an Aldehyde-Functionalized Hydrophilic Polymer Brush

Compared to lipids, block copolymer vesicles are potentially robust nanocontainers for enzymes owing to their enhanced chemical stability, particularly in challenging environments. Herein we report that cis-diol-functional diblock copolymer vesicles can be chemically adsorbed onto a hydrophilic aldehyde-functional polymer brush via acetal bond formation under mild conditions (pH 5.5, 20 °C). Quartz crystal microbalance studies indicated an adsorbed amount, Γ, of 158 mg m-2 for vesicle adsorption onto such brushes, whereas negligible adsorption (Γ = 0.1 mg m-2) was observed for a control experiment conducted using a cis-diol-functionalized brush. Scanning electron microscopy and ellipsometry studies indicated a mean surface coverage of around 30% at the brush surface, which suggests reasonably efficient chemical adsorption. Importantly, such vesicles can be conveniently loaded with a model enzyme (horseradish peroxidase, HRP) using an aqueous polymerization-induced self-assembly formulation. Moreover, the immobilized vesicles remained permeable toward small molecules while retaining their enzyme payload. The enzymatic activity of such HRP-loaded vesicles was demonstrated using a well-established colorimetric assay. In principle, this efficient vesicle-on-brush strategy can be applied to a wide range of enzymes and functional proteins for the design of next-generation immobilized nanoreactors for enzyme-mediated catalysis.

Physically and Chemically Compartmentalized Polymersomes for Programmed Delivery and Biological Applications

Multicompartment polymersomes (MCPs) refer to polymersomes that not only contain one single compartment, either in the membrane or in the internal cavity, but also mimic the compartmentalized structure of living cells, attracting much attention in programmed delivery and biological applications. The investigation of MCPs may promote the application of soft nanomaterials in biomedicine. This Review seeks to highlight the recent advances of the design principles, synthetic strategies, and biomedical applications of MCPs. The compartmentalization types including chemical, physical, and hybrid compartmentalization are discussed. Subsequently, the design and controlled synthesis of MCPs by the self-assembly of amphiphilic polymers, double emulsification, coprecipitation, microfluidics and particle assembly, etc. are summarized. Furthermore, the diverse applications of MCPs in programmed delivery of various cargoes and biological applications including cancer therapy, antimicrobials, and regulation of blood glucose levels are highlighted. Finally, future perspectives of MCPs from the aspects of controlled synthesis and applications are proposed.

Week-long normoglycaemia in diabetic mice and minipigs via a subcutaneous dose of a glucose-responsive insulin complex

Glucose-responsive formulations of insulin can increase its therapeutic index and reduce the burden of its administration. However, it has been difficult to develop single-dosage formulations that can release insulin in both a sustained and glucose-responsive manner. Here we report the development of a subcutaneously injected glucose-responsive formulation that nearly does not trigger the formation of a fibrous capsule and that leads to week-long normoglycaemia and negligible hypoglycaemia in mice and minipigs with type 1 diabetes. The formulation consists of gluconic acid-modified recombinant human insulin binding tightly to poly-L-lysine modified by 4-carboxy-3-fluorophenylboronic acid via glucose-responsive phenylboronic acid-diol complexation and electrostatic attraction. When the insulin complex is exposed to high glucose concentrations, the phenylboronic acid moieties of the polymers bind rapidly to glucose, breaking the complexation and reducing the polymers' positive charge density, which promotes the release of insulin. The therapeutic performance of this long-acting single-dose formulation supports its further evaluation and clinical translational studies.

Membrane and Lumen-Compartmentalized Polymersomes for Biocatalysis and Cell Mimics

Compartmentalization is a crucial feature of a natural cell, manifested in cell membrane and inner lumen. Inspired by the cellular structure, multicompartment polymersomes (MCPs), including membrane-compartmentalized polymersomes and lumen-compartmentalized polymersomes (polymersomes-in-polymersomes), have aroused great expectations for biological applications such as biocatalysis and cell mimics in the past decades. Compared with traditional polymersomes, MCPs have advantages in encapsulating multiple enzymes separately for multistep enzymatic cascade reactions. In this review, first, the design principles and preparation methods of membrane-compartmentalized and lumen-compartmentalized polymersomes are summarized. Next, recent advances of MCPs as nanoreactors and cell mimics to mimic subcellular organelles or artificial cells are discussed. Finally, the future research directions of MCPs are prospected.

Glucose-Responsive Self-Regulated Injectable Silk Fibroin Hydrogel for Controlled Insulin Delivery

Stimuli-responsive drug delivery systems are gaining importance in personalized medicine to deliver therapeutic doses in response to disease-specific stimulation. Pancreas-mimicking glucose-responsive insulin delivery systems offer improved therapeutic outcomes in the treatment of type 1 and advanced stage of type 2 diabetic conditions. Herein, we present a glucose-responsive smart hydrogel platform based on phenylboronic acid-functionalized natural silk fibroin protein for regulated insulin delivery. The modified protein was synergistically self-assembled and cross-linked through β-sheet and phenylboronate ester formation. The dynamic nature of the bonding confers smooth injectability through the needle. The cross-linked hydrogel structures firmly hold the glucose-sensing element and insulin in its pores and contribute to long-term sensing and drug storage. Under hyperglycemic conditions, the hydrogen peroxide generated from the sensing element induces hydrogel matrix degradation by oxidative cleavage, enabling insulin release. In vivo studies in a type 1 diabetic Wistar rat model revealed that the controlled insulin release from the hydrogel restored diabetic glucose level to physiological conditions for 36 h. This work establishes the functional modification of silk fibroin into a glucose-responsive hydrogel platform for regulated and functional insulin delivery application.

Seeded RAFT Polymerization-Induced Self-assembly: Recent Advances and Future Opportunities

Over the past decade, polymerization-induced self-assembly (PISA) has fully proved its versatility for scale-up production of block copolymer nanoparticles with tunable sizes and morphologies; yet, there are still some limitations. Recently, seeded PISA approaches combing PISA with heterogeneous seeded polymerizations have been greatly explored and are expected to overcome the limitations of traditional PISA. In this review, recent advances in seeded PISA that have expanded new horizons for PISA are highlighted including i) general considerations for seeded PISA (e.g., kinetics, the preparation of seeds, the selection of monomers), ii) morphological evolution induced by seeded PISA (e.g., from corona-shell-core nanoparticles to vesicles, vesicles-to-toroid, disassembly of vesicles into nanospheres), and iii) various well-defined nanoparticles with hierarchical and sophisticated morphologies (e.g., multicompartment micelles, porous vesicles, framboidal vesicles, AXn -type colloidal molecules). Finally, new insights into seeded PISA and future perspectives are proposed.

Polymeric Bowl-Shaped Nanoparticles: Hollow Structures with a Large Opening on the Surface

Polymeric bowl-shaped nanoparticles (BNPs) are anisotropic hollow structures with large openings on the surface, which have shown advantages such as high specific area and efficient encapsulation, delivery and release of large-sized cargoes on demand compared to solid nanoparticles or closed hollow structures. Several strategies have been developed to prepare BNPs based on either template or template-free methods. For instance, despite the widely used self-assembly strategy, alternative methods including emulsion polymerization, swelling and freeze-drying of polymeric spheres, and template-assisted approaches have also been developed. It is attractive but still challenging to fabricate BNPs due to their unique structural features. However, there is still no comprehensive summary of BNPs up to now, which significantly hinders the further development of this field. In this review, the recent progress of BNPs will be highlighted from the perspectives of design strategies, preparation methods, formation mechanisms, and emerging applications. Moreover, the future perspectives of BNPs will also be proposed.

Differential expression of coagulation pathway-related proteins in diabetic urine exosomes

BACKGROUND

Coagulation function monitoring is important for the occurrence and development of diabetes. A total of 16 related proteins are involved in coagulation, but how these proteins change in diabetic urine exosomes is unclear. To explore the expression changes of coagulation-related proteins in urine exosomes and their possible roles in the pathogenesis of diabetes, we performed proteomic analysis and finally applied them to the noninvasive monitoring of diabetes.

METHODS

Subject urine samples were collected. LC-MS/MS was used to collect the information on coagulation-related proteins in urine exosomes. ELISA, mass spectrometry and western blotting were used to further verify the differential protein expression in urine exosomes. Correlations with clinical indicators were explored, and receiver operating characteristic (ROC) curves were drawn to evaluate the value of differential proteins in diabetes monitoring.

RESULTS

Analyzing urine exosome proteomics data, eight coagulation-related proteins were found in this study. Among them, F2 was elevated in urine exosomes of diabetic patients compared with healthy controls. The results of ELISA, mass spectrometry and western blotting further verified the changes in F2. Correlation analysis showed that the expression of urine exosome F2 was correlated with clinical lipid metabolism indexes, and the concentration of F2 was strongly positively correlated with blood TG levels (P < 0.05). ROC curve analysis showed that F2 protein in urine exosomes had a good monitoring value for diabetes.

CONCLUSION

Coagulation-related proteins were expressed in urine exosomes. Among them, F2 was increased in diabetic urine exosomes and may be a potential biomarker for monitoring diabetic changes.

Catalytic Modification of Porous Two-Dimensional Ni-MOFs on Portable Electrochemical Paper-Based Sensors for Glucose and Hydrogen Peroxide Detection

Rapid and accurate detection of changes in glucose (Glu) and hydrogen peroxide (H₂O₂) concentrations is essential for the predictive diagnosis of diseases. Electrochemical biosensors exhibiting high sensitivity, reliable selectivity, and rapid response provide an advantageous and promising solution. A porous two-dimensional conductive metal-organic framework (cMOF), Ni-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), was prepared by using a one-pot method. Subsequently, it was employed to construct enzyme-free paper-based electrochemical sensors by applying mass-producing screen-printing and inkjet-printing techniques. These sensors effectively determined Glu and H₂O₂ concentrations, achieving low limits of detection of 1.30 μM and 2.13 μM, and high sensitivities of 5573.21 μA μM^-1 cm^-2 and 179.85 μA μM^-1 cm^-2, respectively. More importantly, the Ni-HHTP-based electrochemical sensors showed an ability to analyze real biological samples by successfully distinguishing human serum from artificial sweat samples. This work provides a new perspective for the use of cMOFs in the field of enzyme-free electrochemical sensing, highlighting their potential for future applications in the design and development of new multifunctional and high-performance flexible electronic sensors.

Colorimetric and electrochemical integrated dual-mode detection of glucose by utilizing CoOOH@Cu nanosheets as peroxidase mimetics

Herein, we developed a colorimetric and electrochemical integrated dual-mode assay for glucose detection by utilizing CoOOH@Cu nanosheets as peroxidase mimetics. With the advantages of self-calibration, sensitivity and lower sample cost, this designed dual-mode assay offers great potential in blood glucose analysis.

On demand regulation of blood glucose level by biocompatible oxidized starch-Con A nanogels for glucose-responsive release of exenatide

Diabetes mellitus is a long-term chronic disease characterized by abnormal high level blood glucose (BG). An artificial closed-loop system that mimics pancreatic β-cells and releases insulin on demand has potential to improve the therapeutic efficiency of diabetes. Herein, a lectin Concanavalin A modified oxidized starch nanogel was designed to regulate glucose dynamically according to different glucose concentrations. The nanogels were formed by double cross-linking the Concanavalin A and glucose units on oxidized starch via specific binding and amide bonds to achieve the high drug loading and glucose responsiveness. The results showed that oxidized starch nanogels prolonged the half-life of antidiabetic peptide drug exenatide and released it in response to high BG concentrations. It could absorb BG at a high level and maintain glucose homeostasis. Besides, the oxidized starch nanogels performed well in recovering regular BG level from hyperglycemia state and maintaining in euglycemia state that fitted in a biological rhythm. In addition, the nanogels showed high biocompatibility in vivo and could improve plasma half-life and therapeutic efficacy of exenatide. Overall, the nanogels protected peptide drugs from degradation in plasma as a glucose-responsive platform showing a high potential for peptide drugs delivery and antidiabetic therapy.

Polythionoester Vesicle: An Efficient Polymeric Platform for Tuning H2S Release

Hydrogen sulfide (H₂S) serves as a key gaseous regulator that not only directs many physiological activities, but also manifests therapeutic benefits to many diseases. Developing H₂S vehicle platforms for its local delivery and long-acting release is important to achieve target gas therapy. Most of the known H₂S-donating polymers contain labile thioester scaffolds within their structures that suffer from the issue of low gas releasing efficiency. Here we present the use of thionoester, a constitutional isomer of thioester, as the functional unit to build a structural platform of cysteine-triggered H₂S donor polymer, polythionoester. Simple exchange of the sulfur and oxygen positions in the carbonyl sulfide scaffold makes the polythionoesters undergo a distinct mechanism of H₂S production, which can largely improve the gas-releasing efficiency (>80%). Moreover, the thionoester-containing block copolymers can self-assemble into vesicles in an aqueous media. We discover that control over the size effect can adjust the vesicle disassembly rate and gas-releasing kinetics. A tunable half-life of H₂S generation (2.6-9.8 h) can be accessed by tailoring the vesicle dimension. This allows such polymersomes to be potential as a gas nanodelivery system for long-lasting gas therapeutics.

Current Perspectives on Synthetic Compartments for Biomedical Applications

Nano- and micrometer-sized compartments composed of synthetic polymers are designed to mimic spatial and temporal divisions found in nature. Self-assembly of polymers into compartments such as polymersomes, giant unilamellar vesicles (GUVs), layer-by-layer (LbL) capsules, capsosomes, or polyion complex vesicles (PICsomes) allows for the separation of defined environments from the exterior. These compartments can be further engineered through the incorporation of (bio)molecules within the lumen or into the membrane, while the membrane can be decorated with functional moieties to produce catalytic compartments with defined structures and functions. Nanometer-sized compartments are used for imaging, theranostic, and therapeutic applications as a more mechanically stable alternative to liposomes, and through the encapsulation of catalytic molecules, i.e., enzymes, catalytic compartments can localize and act in vivo. On the micrometer scale, such biohybrid systems are used to encapsulate model proteins and form multicompartmentalized structures through the combination of multiple compartments, reaching closer to the creation of artificial organelles and cells. Significant progress in therapeutic applications and modeling strategies has been achieved through both the creation of polymers with tailored properties and functionalizations and novel techniques for their assembly.

Advances in oral peptide drug nanoparticles for diabetes mellitus treatment

Peptide drugs play an important role in diabetes mellitus treatment. Oral administration of peptide drugs is a promising strategy for diabetes mellitus because of its convenience and high patient compliance compared to parenteral administration routes. However, there are a series of formidable unfavorable conditions present in the gastrointestinal (GI) tract after oral administration, which result in the low oral bioavailability of these peptide drugs. To overcome these challenges, various nanoparticles (NPs) have been developed to improve the oral absorption of peptide drugs due to their unique in vivo properties and high design flexibility. This review discusses the unfavorable conditions present in the GI tract and provides the corresponding strategies to overcome these challenges. The review provides a comprehensive overview on the NPs that have been constructed for oral peptide drug delivery in diabetes mellitus treatment. Finally, we will discuss the rational application and give some suggestions that can be utilized for the development of oral peptide drug NPs. Our aim is to provide a systemic and comprehensive review of oral peptide drug NPs that can overcome the challenges in GI tract for efficient treatment of diabetes mellitus.

•Oral administration of peptide drugs is a promising strategy for diabetes mellitus treatment

•A series of formidable unfavorable conditions in gastrointestinal tract result in the low oral bioavailability of peptide drugs

•Nanoparticles can improve the oral bioavailability of peptide drugs

Transformation of Amorphous Nanobowls to Crystalline Ellipsoids Induced by Trans-Cis Isomerization of Azobenzene

The stimuli-responsive transition of nanostructures from amorphous to crystalline state is of high interest in polymer science, but is still challenging. Herein, we demonstrate the transformation of amorphous nanobowls to crystalline ellipsoids triggered by UV induced trans-cis isomerization, using an azobenzene-containing amphiphilic homopolymer (PAzoAA) as building block. The amide bond and azobenzene pendants are introduced to the side chain of PAzoAA to afford hydrogen bonding and π-π interaction, which promotes the formation of nanobowls rather than spherical nanostructures. Upon exposed to UV irradiation, trans-cis isomerization of azobenzene pendants occurs, leading to the increase of hydrophilicity and destruction of π-π interaction, further resulting in the disassembly of the nanobowls. Then the PAzoAA re-assembles to form crystalline ellipsoids instead of amorphous nanostructures when recovered at 70°C without UV light. We further confirm that the high incubation temperature after UV irradiation is critical for the cis-trans transformation and the high mobility of the polymer chains to facilitate the regular rearrangement of azobenzene pendants. Overall, we propose a facile method to achieve the transformation of amorphous nanobowls to crystalline ellipsoids, which may bring new insight into preparation of crystalline nanoparticles using amorphous precursors. This article is protected by copyright. All rights reserved.

Upper Critical Solution Temperature Polyvalent Scaffolds Aggregate and Exterminate Bacteria

Specific recognition and strong affinities of bacteria receptors with the host cell glycoconjugates pave the way to control the bacteria aggregation and kill bacteria. Herein, using aggregation-induced emission (AIE) molecules decorated upper critical solution temperature (UCST) polyvalent scaffold (PATC-GlcN), an approach toward visualizing bacteria aggregation and controlling bacteria-polyvalent scaffolds affinities under temperature stimulus is described. Polyvalent scaffolds with diblocks, one UCST block PATC of polyacrylamides showing a sharp UCST transition and typical AIE behavior, the second bacteria recognition block GlcN of hydrophilic glucosamine modified polyacrylamide, are prepared through a reversible addition and fragmentation chain transfer polymerization. Aggregated chain conformation of polyvalent scaffolds at temperature below UCST induces the aggregation of E. coli ATCC8739, because of the high density of glucosamine moieties, whereas beyond UCST, the hydrophilic state of the scaffolds dissociates the bacteria aggregation. The sweet-talking of bacteria toward the polyvalent scaffolds can be visualized by the fluorescent imaging technique, simultaneously. Due to the specific recognition of polyvalent scaffolds with bacteria, the photothermal agent IR780 loaded PATC-GlcN shows the targeted killing ability toward E. coli ATCC8739 in vitro and in vivo under NIR radiation.

Block Copolymer Vesicles with Tunable Membrane Thicknesses and Compositions Prepared by Aqueous Seeded Photoinitiated Polymerization-Induced Self-Assembly at Room Temperature

Block copolymer vesicles with diverse functionalities and intrinsic hollow structures have received considerable attention due to their broad applications in biomedical fields, including drug delivery, bioimaging, theranostics, gene therapy, etc. However, efficient preparation of block copolymer vesicles with tunable membrane thicknesses and compositions under mild conditions is still a challenge. Herein, we report an aqueous seeded photoinitiated polymerization-induced self-assembly (photo-PISA) for the precise preparation of block copolymer vesicles at room temperature. By changing the total degree of polymerization (DP) of the hydrophobic block in seeded photo-PISA, one can easily tune the membrane thickness without compromising the morphology of vesicles. Moreover, by adding different comonomers such as hydrophobic monomers, hydrophilic monomers, and cross-linkers into seeded photo-PISA, vesicles with different compositions could be prepared without compromising the morphology and colloidal stability. Polymerization kinetics show that seeded photo-PISA can skip the step of in situ self-assembly with a short homogeneous polymerization stage being observed. To demonstrate potential biological applications, enzymatic nanoreactors were constructed by loading horseradish peroxidase (HRP) inside vesicles via seeded photo-PISA. The enzymatic properties of these nanoreactors could be easily regulated by changing the membrane thickness and hydrophobicity. It is expected that this method can provide a facile platform for the precise preparation of block copolymer vesicles that may find applications in different fields.

Detection of glucose in diabetic tears by using gold nanoparticles and MXene composite surface-enhanced Raman scattering substrates

Diabetes has become one of the three chronic non-communicable diseases threatening human health in the world, and the detection of glucose concentration is of great importance for the prevention and treatment of diabetes. The noninvasive detection of glucose in tears has attracted interest over the past several decades, however, time-consuming, expensive equipment, and specialist technicians make tear analysis still challenging. Here, flexible surface-enhanced Raman scattering (SERS) substrates composed of gold nanoparticles (AuNPs) and two-dimensional MXene Ti₃C₂T_X nanosheets have been designed. The GMXeP (gold nanoparticles with MXene nanosheets loaded on paper) SERS substrates show good sensitivity, reproducibility, and stability, yielding an enhancement factor (EF) of 3.7 × 10⁵ at the concentration of 10^-9 M. The GMXeP SERS substrates are used to detect glucose of diabetic tears within a linear range of 1-50 μM, the lowest detection concentration is 0.39 μM and the significant correlation between tear glucose and blood glucose indicates that this method is suitable for sensitive and noninvasive detection of blood glucose.

Tailor-made Glycopolymers via Reversible Deactivation Radical Polymerization: Design, Properties and Applications

Investigating the underlying mechanism of biological interactions using glycopolymer is becoming increasingly important owing to their unique recognition properties. The multivalent interactions between lectin and glycopolymer are significantly influenced by...

Emerging Theranostic Nanomaterials in Diabetes and Its Complications

Diabetes mellitus (DM) refers to a group of metabolic disorders that are characterized by hyperglycemia. Oral subcutaneously administered antidiabetic drugs such as insulin, glipalamide, and metformin can temporarily balance blood sugar levels, however, long-term administration of these therapies is associated with undesirable side effects on the kidney and liver. In addition, due to overproduction of reactive oxygen species and hyperglycemia-induced macrovascular system damage, diabetics have an increased risk of complications. Fortunately, recent advances in nanomaterials have provided new opportunities for diabetes therapy and diagnosis. This review provides a panoramic overview of the current nanomaterials for the detection of diabetic biomarkers and diabetes treatment. Apart from diabetic sensing mechanisms and antidiabetic activities, the applications of these bioengineered nanoparticles for preventing several diabetic complications are elucidated. This review provides an overall perspective in this field, including current challenges and future trends, which may be helpful in informing the development of novel nanomaterials with new functions and properties for diabetes diagnosis and therapy.

Polymers with multiple functions: α,ω-macromolecular photoinitiators/chain transfer agents used in aqueous photoinitiated polymerization-induced self-assembly

A series of α,ω-functionalized polymers with a photoinitiator end group and a RAFT end group were synthesized and employed as macromolecular photoinitiators/chain transfer agents in aqueous photoinitiated polymerization-induced self-assembly.

Painless and flexible bi-directional blood glucose-regulating system inspired by inverter air conditioner

Pursuing painless and flexible blood glucose regulating has been a century-long arduous mission. The current therapeutic systems can only regulate blood glucose unidirectionally (reduce), and the adjustment range is large,...

The assembly of integrated continuous flow platform for on-demand rosiglitazone and pioglitazone synthesis

Manufacturing thiazolidinediones in a batch process is often carried out at different locations, where each successive batch collects a certain amount of intermediate followed by its transportation to another location.

Polymeric Nanomaterials for Efficient Delivery of Antimicrobial Agents

Bacterial infections have threatened the lives of human beings for thousands of years either as major diseases or complications. The elimination of bacterial infections has always occupied a pivotal position in our history. For a long period of time, people were devoted to finding natural antimicrobial agents such as antimicrobial peptides (AMPs), antibiotics and silver ions or synthetic active antimicrobial substances including antimicrobial peptoids, metal oxides and polymers to combat bacterial infections. However, with the emergence of multidrug resistance (MDR), bacterial infection has become one of the most urgent problems worldwide. The efficient delivery of antimicrobial agents to the site of infection precisely is a promising strategy for reducing bacterial resistance. Polymeric nanomaterials have been widely studied as carriers for constructing antimicrobial agent delivery systems and have shown advantages including high biocompatibility, sustained release, targeting and improved bioavailability. In this review, we will highlight recent advances in highly efficient delivery of antimicrobial agents by polymeric nanomaterials such as micelles, vesicles, dendrimers, nanogels, nanofibers and so forth. The biomedical applications of polymeric nanomaterial-based delivery systems in combating MDR bacteria, anti-biofilms, wound healing, tissue engineering and anticancer are demonstrated. Moreover, conclusions and future perspectives are also proposed.

Bone-Targeting Polymer Vesicles for Effective Therapy of Osteoporosis

With the aging of the population, postmenopausal osteoporosis becomes increasingly widespread and severe as fractures caused by osteoporosis may lead to permanent disabilities and even death. Inspired by extracellular vesicles that participate in bone remodeling, we present a biomimicking polymer vesicle for bone-targeted β-estradiol (E₂) delivery. This vesicle is self-assembled from a poly(ε-caprolactone)₂₈-block-poly[(l-glutamic acid)₇-stat-(l-glutamic acid-alendronic acid)₄] (PCL₂₈-b-P[Glu₇-stat-(Glu-ADA)₄]) diblock copolymer. The alendronic acid (ADA) on the coronas endows the polymer vesicles with a high bone affinity and acts synergistically with E₂ to achieve an enhanced therapeutic effect. As confirmed with ovariectomized osteoporosis rat models, bone loss was significantly reversed as the recovery rates of total BMD (bone mineral density) and trabecular BMD were 70.4% and 99.3%, respectively. Overall, this work provides fresh insight into the treatment of osteoporosis.

Polymer Vesicles for Antimicrobial Applications

Polymer vesicles, hollow nanostructures with hydrophilic cavity and hydrophobic membrane, have shown significant potentials in biomedical applications including drug delivery, gene therapy, cancer theranostics, and so forth, due to their unique cell membrane-like structure. Incorporation with antibacterial active components like antimicrobial peptides, etc., polymer vesicles exhibited enhanced antimicrobial activity, extended circulation time, and reduced cell toxicity. Furthermore, antibacterial, and anticancer can be achieved simultaneously, opening a new avenue of the antimicrobial applications of polymer vesicles. This review seeks to highlight the state-of-the-art of antimicrobial polymer vesicles, including the design strategies and potential applications in the field of antibacterial. The structural features of polymer vesicles, preparation methods, and the combination principles with antimicrobial active components, as well as the advantages of antimicrobial polymer vesicles, will be discussed. Then, the diverse applications of antimicrobial polymer vesicles such as wide spectrum antibacterial, anti-biofilm, wound healing, and tissue engineering associated with their structure features are presented. Finally, future perspectives of polymer vesicles in the field of antibacterial is also proposed.

Expanding the Scope of Polymerization-Induced Self-Assembly: Recent Advances and New Horizons

Over the past decade or so, polymerization-induced self-assembly (PISA) has become a versatile method for rational preparation of concentrated block copolymer nanoparticles with a diverse set of morphologies. Much of the PISA literature has focused on the preparation of well-defined linear block copolymers by using linear macromolecular chain transfer agents (macro-CTAs) with high chain transfer constants. In this review, a recent process is highlighted from an unusual angle that has expanded the scope of PISA including i) synthesis of block copolymers with nonlinear architectures (e.g., star block copolymer, branched block copolymer) by PISA, ii) in situ synthesis of blends of polymers by PISA, and iii) utilization of macro-CTAs with low chain transfer constants in PISA. By highlighting these important examples, new insights into the research of PISA and future impact these methods will have on polymer and colloid synthesis are provided.

Giant Polymer Vesicles with a Latticelike Membrane

Hierarchical self-assembly offers great possibilities to mimic biological systems with finely arranged complex structures. Herein, we demonstrate the preparation and formation mechanism of an unusual giant polymer vesicle with a latticelike membrane (GVLM). This GVLM is formed by fusion-induced particle assembly (FIPA) of small vesicles that are self-assembled from poly(ethylene oxide)-block-poly[(2-(tetrahydrofuranyloxy)ethyl methacrylate)-stat-(6-(3,3-diphenylnaphthopyranyloxy)hexyl methacrylate)] [PEO₄₃-b-P(TMA₂₂-stat-NMA₄)]. Flexible TMA units with high chain mobility and relatively rigid NMA units with intrinsic π-π stacking form the hydrophobic block. These units act as "antifusion" and "profusion" components, respectively. The latticelike membrane of the final GVLM consists of hundreds of small polymer vesicles that are interconnected via multiple interactions. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies show that the diameter of the GVLMs is 800-1000 nm. Overall, we provide a new insight into the judicious preparation of hierarchical nanostructures via chemical synthesis and FIPA.

Ordered Conformation-Regulated Vesicular Membrane Permeability

In nature, the folding and conformation of proteins can control the cell or organelle membrane permeability and regulate the life activities. Here we report the first example of synthetic polypeptide vesicles that regulate their permeability via ordered transition of secondary conformations, in a manner similar to biological systems.  The polymersomes undergo a β-sheet to α-helix transition in response to reactive oxygen species (ROS), leading to wall thinning without loss of vesicular integrity. The change  of membrane structure increases the vesicular permeability and enables specific transport of payloads with different molecular weights.The change of membrane structure increases the vesicular permeability.  As a proof-of-concept, the polymersomes encapsulating enzymes could serve as nanoreactors and carries for glucose-stimulated insulin secretion in vivo inspired by human glucokinase, resulting in safe and effective treatment of type 1 diabetes mellitus in mouse models. This study will help understand the biology of biomembranes and facilitate the engineering of nanoplatforms for biomimicry, biosensing, and controlled delivery applications.

On-demand transdermal insulin delivery system for type 1 diabetes therapy with no hypoglycemia risks

Diabetes is a metabolic disease that is affecting an ever-increasing number of people worldwide, resulting in increased burdens on healthcare systems and societies. Constant monitoring of blood glucose levels is required to prevent serious or even deadly complications. One major challenge of diabetes management is the simple and timely administration of insulin to facilitate consistent blood glucose regulation and reduce the incidence of hypoglycemia. With this research, we construct an insulin delivery system, the delivery system is comprised of phenylboronic acid based fluorescent probes, which is used as glucose responsive linkers, mesoporous silica nanoparticles providing an insulin reservoir, and zinc oxide nanoparticles used as gate keepers. The system with glucose sensitive responsive linker exhibits controlled release of insulin under high glucose concentrations, providing prolonged blood glucose regulation and no risks of hypoglycemia. Furthermore, the system is combined with a hyaluronic-acid based microneedle patch, which exhibit efficient skin penetration for transdermal delivery. With our system, the nanoparticles provide outstanding in vivo glucose regulation when administrated by subcutaneous injection or via transdermal microneedle patch. We anticipate that our biocompatible smart glucose responsive microneedle patch (SGRM patch) will facilitate the development of clinically useful systems.

Hypoxia adipose stem cell-derived exosomes promote high-quality healing of diabetic wound involves activation of PI3K/Akt pathways

Refractory diabetic wounds can cause persistent inflammation and delayed healing due to hypoxia. Currently, no optimal solution is available. Exosomes of adipose stem cells (ADSCs-exo) may promote skin wound healing, however, molecular mechanisms remains mysterious. We found significantly enhanced survival and proliferation of adipose stem cells after hypoxia induction compared to normoxia. Here, we aimed to investigate if hypoxic adipose stem cells exosomes (HypADSCs-exo) participate in hypoxia adaptability and accelerate diabetic wound healing. Based on high-throughput sequencing, 215 microRNAs (miRNAs) were upregulated and 369 miRNAs downregulated in HypADSCs-exo compared to ADSCs-exo. Up-regulated miR-21-3p, miR-126-5p, miR-31-5p whereas down-regulated gene miR-99b and miR-146-a correlated with wound healing. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), miRNAs might regulate cell metabolism, differentiation and Transforming growth factor-β (TGF-β) function. Consistently, HpyADSCs-exo could promote diabetic wounds healing and inhibit inflammation through PI3K/AKT signaling pathway. Collectively, HpyADSCs-exo can promote diabetic wound healing as an alternative strategy to improve wound healing.

How the Reactive End Group of Macro-RAFT Agent Affects RAFT-Mediated Emulsion Polymerization-Induced Self-Assembly

Polymerization-induced self-assembly via reversible addition-fragmentation chain transfer (RAFT)-mediated emulsion polymerization is an emerging method in which macro-RAFT agents are chain extended with hydrophobic monomers in water to form block copolymer nano-objects. However, almost all RAFT-mediated emulsion polymerizations are limited to AB diblock copolymers by using monofunctional macro-RAFT agents with non-reactive end groups. In this study, the first investigation on how the reactive end group of macro-RAFT agent affects RAFT-mediated emulsion polymerization is reported. Three macro-RAFT agents with different end groups are synthesized and employed in RAFT-mediated emulsion polymerization. Effects of end groups on morphologies of block copolymer nano-objects and polymerization process are studied. Block copolymer nano-objects prepared by using an asymmetric difunctional macro-RAFT agent can be functionalized by further chain extension on the surface. It is expected that the current study will not only expand the scope of RAFT-mediated emulsion polymerization, but also provide a novel strategy to prepare functional polymer nanoparticles.

Construction of Highly Ordered Glyco-Inside Nano-Assemblies through RAFT Dispersion Polymerization of Galactose-Decorated Monomer

Glyco-assemblies derived from amphiphilic sugar-decorated block copolymers (ASBCs) have emerged prominently due to their wide application, for example, in biomedicine and as drug carriers. However, to efficiently construct these glyco-assemblies is still a challenge. Herein, we report an efficient technology for the synthesis of glyco-inside nano-assemblies by utilizing RAFT polymerization of a galactose-decorated methacrylate for polymerization-induced self-assembly (PISA). Using this approach, a series of highly ordered glyco-inside nano-assemblies containing intermediate morphologies were fabricated by adjusting the length of the hydrophobic glycoblock and the polymerization solids content. A specific morphology of complex vesicles was captured during the PISA process and the formation mechanism is explained by the morphology of its precursor and intermediate. Thus, this method establishes a powerful route to fabricate glyco-assemblies with tunable morphologies and variable sizes, which is significant to enable the large-scale fabrication and wide application of glyco-assemblies.

Injectable Biodegradable Polymeric Complex for Glucose-Responsive Insulin Delivery

Insulin therapy is the central component of treatment for type 1 and advanced type 2 diabetes; however, its narrow therapeutic window is associated with a risk of severe hypoglycemia. A glucose-responsive carrier that demonstrates consistent and slow basal insulin release under a normoglycemic condition and accelerated insulin release in response to hyperglycemia in real-time could offer effective blood glucose regulation with reduced risk of hypoglycemia. Here, we describe a poly(l-lysine)-derived biodegradable glucose-responsive cationic polymer for constructing polymer-insulin complexes for glucose-stimulated insulin delivery. The effects of the modification degree of arylboronic acid in the synthesized cationic polymer and polymer-to-insulin ratio on the glucose-dependent equilibrated free insulin level and the associated insulin release kinetics have been studied. In addition, the blood glucose regulation ability of these complexes and the associated glucose challenge-triggered insulin release are evaluated in type 1 diabetic mice.

Bolaamphiphile-based supramolecular gels with drugs eliciting membrane effects

Supramolecular chemistry has garnered important interest in recent years toward improving therapeutic efficacy via drug delivery approaches. Although self-assemblies have been deeply investigated, the design of novel drugs leveraging supramolecular chemistry is less known. In this contribution, we show that a Low Molecular Weight Gel (LMWG) can elicit cancer cell apoptosis. This biological effect results from the unique supramolecular properties of a bolaamphiphile-based gelator, which allow for strong interaction with the lipid membrane. This novel supramolecular-drug paradigm opens up new possibilities for therapeutic applications targeting membrane lipids.