Sugar-Breathing Glycopolymersomes for Regulating Glucose Level

Diabetes mellitus is a chronic, life-threatening illness that affects people of every age and ethnicity. It is a long-term pain for those who are affected and must regulate their blood glucose level by frequent subcutaneous injection of insulin every day. Herein, we propose a noninsulin and antidiabetic drug-free strategy for regulating blood glucose level by a nanosized “sugar sponge” which is a lectin-bound glycopolymersome capable of regulating glucose due to the dynamic recognition between the lectin and different carbohydrates. The glycopolymersome is self-assembled from poly­(ethylene oxide)-<i>block</i>-poly­[(7-(2-methacryloyloxyethoxy)-4-methylcoumarin)-<i>stat</i>-2-(diethylamino)­ethyl methacrylate-<i>stat</i>-(α-d-glucopyranosyl)­ethyl methacrylate] [PEO-<i>b</i>-P­(CMA-<i>stat</i>-DEA-<i>stat</i>-GEMA)]. The lectin bound in the glycopolymersome has different affinity for the glucose in the blood and the glucosyl group in the glycopolymersome. Therefore, this sugar sponge functions as a glucose storage unit by dynamic sugar replacement: The lectin in the sugar sponge will bind and store the glucose from its surrounding solution when the glucose concentration is too high and will release the glucose when the glucose concentration is too low. In vitro, this sugar-breathing behavior is characterized by a remarkable size change of the sugar sponge due to the swelling/shrinkage at high/low glucose levels, which can be used for blood sugar monitoring. In vivo, this sugar sponge showed an excellent antidiabetic effect for type I diabetic mice within 2 days upon one dose, which is much longer than traditional long-acting insulin. Overall, this concept of “controlling sugar levels with sugar” opens new avenues for regulating the blood glucose level without the involvement of insulin or other antidiabetic drugs

Efficient Removal of Polycyclic Aromatic Hydrocarbons, Dyes, and Heavy Metal Ions by a Homopolymer Vesicle

It is an important challenge to effectively remove environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs), dyes, and heavy metal ions at a low cost. Herein, we present a multifunctional homopolymer vesicle self-assembled from a scalable homopolymer, poly­(amic acid) (PAA), at room temperature. The vesicle can efficiently eliminate PAHs, cationic dyes, and heavy metal ions from water based on π–π stacking, hydrophobic effect, and electrostatic interactions with the pollutants. The residual concentrations of PAHs, cationic dyes, and heavy metal ions (such as Ni²⁺) in water are lower than 0.60 and 0.30 parts per billion (ppb) and 0.095 parts per million (ppm), respectively, representing a promising adsorbent for water remediation. Furthermore, precious metal ions such as Ag⁺ can be recovered into silver nanoparticles by <i>in situ</i> reduction on the membrane of PAA vesicles to form a silver nanoparticle/vesicle composite (Ag@vesicle) that can effectively catalyze the reduction of toxic pollutants such as aromatic nitro-compounds and be recycled for more than ten times

Multifunctional Biocompatible and Biodegradable Folic Acid Conjugated Poly(ε-caprolactone)–Polypeptide Copolymer Vesicles with Excellent Antibacterial Activities

Cancer patients after chemotherapy may also suffer bacterial attack due to badly decreased immunity. Although with high bacterial efficacy, conventional antibiotics are prone to inducement of drug resistance and may be not suitable for some cancer patients. In contrast, antibacterial peptides are highly effective in inhibiting bacteria without inducing resistance in pathogens. Presented in this article is a novel kind of highly effective antibacterial peptide-based biocompatible and biodegradable block copolymer vesicle. The copolymer is poly­(ε-caprolactone)-<i>block</i>-poly­[phenylalanine-<i>stat</i>-lysine-<i>stat</i>-(lysine-folic acid)] [PCL₁₉-<i>b</i>-poly­[Phe₁₂-<i>sta</i>t-Lys₉-<i>stat</i>-(Lys-FA)₆]], which can self-assemble into vesicles in aqueous solution. The biocompatible and biodegradable PCL forms the vesicle membrane, whereas the poly­[Phe₁₂-<i>sta</i>t-Lys₉-<i>stat</i>-(Lys-FA)₆] block constitutes the vesicle coronas. Compared to the individual polymer chains, the vesicles showed enhanced antibacterial activities against both Gram-positive and Gram-negative bacteria (16 μg mL^–1) due to the locally concentrated antibacterial poly­[Phe₁₂-<i>stat</i>-Lys₉-<i>stat</i>-(Lys-FA)₆] coronas, which may avoid the inducement of antibiotic-resistant bacteria and side effects of multidrug interactions. Furthermore, folic acid is introduced into the vesicle coronas for potential further applications such as cancer-targeted drug delivery. Moreover, the amino groups can be further functionalized when necessary. This low cytotoxic, biocompatible, biodegradable, and antibacterial vesicle (without antibiotic resistance) may benefit patients after tumor surgery because it is highly anti-inflammatory, and it is possible to deliver the anticancer drug to tumor cells simultaneously

Three-Day Blood Glucose Control via a Glucose Modulator of Glycopolymersome: Sugar versus Sugar

Natural modulators, such as insulin, play a significant role in modulating molecule levels. Inspired by the role of natural modulators, herein, we propose a glucose modulator that is composed of a glycopolymersome only to regulate glucose levels. This insulin- and drug-free strategy can smartly take in and snap out glucose according to the surrounding blood glucose levels (BGLs) by reversible sugar substituting. The glycopolymersome is self-assembled from a biodegradable glycopolymer that is composed of sugar and phenylboronic acid derivative, poly(ε-caprolactone)-block-poly[(3-acrylamidophenylboronic acid-stat-N-acryloyl glucosamine] [PCL-b-P(AAPBA-stat-AGA)]. It exhibits excellent long-term hypoglycemic effects toward type 1 diabetic mice for at least 3 days upon one shot without observed side effects, which is the longest effective sugar-regulation time for the insulin and drug-free strategy. Most notably, we explored the effect of the molecular structure of the glycopolymers on the BGL regulating efficacy, where the glucosyl moiety was polymerized with PBA either randomly or separately. Block-statistical glycopolymersomes exhibited lower binding energy to glucose, better glucose responsiveness, and prolonged hypoglycemic effect due to the abundant intramolecular and intermolecular dynamic covalent bonds between AAPBA and AGA. Our finding confirmed the importance of a block-statistical copolymer structure and the key role of sugar in regulating BGLs without involving medication, which may provide guidance and open new avenues for design blood glucose regulating materials