4 research outputs found
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 Ni<sup>2+</sup>) 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<sup>+</sup> 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)] [PCL<sub>19</sub>-<i>b</i>-poly[Phe<sub>12</sub>-<i>sta</i>t-Lys<sub>9</sub>-<i>stat</i>-(Lys-FA)<sub>6</sub>]], which can self-assemble into
vesicles in aqueous solution. The biocompatible and biodegradable
PCL forms the vesicle membrane, whereas the poly[Phe<sub>12</sub>-<i>sta</i>t-Lys<sub>9</sub>-<i>stat</i>-(Lys-FA)<sub>6</sub>] 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<sup>–1</sup>) due to the locally concentrated antibacterial
poly[Phe<sub>12</sub>-<i>stat</i>-Lys<sub>9</sub>-<i>stat</i>-(Lys-FA)<sub>6</sub>] 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