A new method for green synthesis of activated carbon using chitosan-based hydrogel precursors is reported. Chitosan-based hydrogel materials are designed to absorb trace amounts of non-toxic and non-corrosive activating agent K2CO3 from dilute aqueous solution. The K2CO3 impregnated hydrogels are further freeze-dried and converted to activated carbons with tuneable pore structure by a single-step pyrolysis. Activated carbon with highest pore volume of 0.76 cm3/g and surface area of 2026 m2/g is obtained by using K2CO3 as low as 0.23 g per gram of chitosan hydrogel. It can adsorb maximum CO2 of 4.2 mmol/g at 25 °C and 1 bar. This study demonstrates that biopolymer hydrogels impregnated with trace amounts of K2CO3 are excellent precursor materials to design high surface area carbons for CO2 capture.

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Hydrogel beads prepared from protein nanofibers are popular because of their safety, sleek appearance, and protection of biologically active substances. However, extreme external environmental variations, such as pH and temperature, can limit their practical application. To meet the application requirements of hydrogel beads in different environments, non-covalent mixtures of CaCl2 cross-linked soybean protein nanofibers (SNF) and sodium alginate (SA) were used to prepare hydrogel beads. In the present study, the hardness (782.48 g) and elasticity of hydrogel beads formed at SNF/SA = 7:3 and CaCl2 concentration of 0.1 mol/L were the maximum. Furthermore, the water content and pH swelling also reached a peak (98.68 %, 43.85 g/g) due to the best morphology and regular internal network structure. Meanwhile, the pH-responsive hydrogel beads with added anthocyanins were able to respond to the ambient pH under different temperatures and pH conditions and maintained color stability during 96 h of storage (ΔE < 5). In this experiment, a pH-responsive hydrogel bead based on soybean protein nanofiber (SNF) and sodium alginate (SA) was prepared by simple ionic crosslinking. It provides a theoretical and experimental basis for the future application of plant protein nanofibers as pH-responsive hydrogel materials.

Intramyocardial hydrogel injection is a promising therapy to prevent negative remodeling following myocardial infarction (MI). In this study, we report a mechanism for in-situ gel formation without external stimulation, resulting in an injectable and tissue-retainable hydrogel for MI treatment, and investigate its therapeutic outcomes. A liquid-like polymeric solution comprising poly(3-acrylamidophenylboronic acid-co-acrylamide) (BAAm), polyvinyl alcohol (PVA), and sorbitol (S) increases the viscous modulus by reducing the pre-added sorbitol concentration is developed. This solution achieves a sol-gel transition in-vitro in heart tissue by spontaneously diffusing the sorbitol. After intramyocardial injection, the BAAm/PVA/S with lower initial viscous modulus widely spreads in the myocardium and gelate compared to a viscoelastic alginate (ALG) hydrogel and is retained longer than the BAAm/S solution. Serial echocardiogram analyses prove that injecting the BAAm/PVA/S into the hearts of subacute MI rats significantly increases the fraction shortening and ejection shortening and attenuates the expansion of systolic LV diameter for up to 21 d after injection compared to the saline injection as a control, but the ALG injection does not. In addition, histological evaluation shows that only the BAAm/PVA/S decreases the infarct size and increases the wall thickness 21 d after injection. The BAAm/PVA/S intramyocardial injection is better at restraining systolic ventricular dilatation and cardiac failure in the rat MI model than in the control groups. Our findings highlight an effective injectable hydrogel therapy for MI by optimizing injectability-dependent distribution and retention of injected material. STATEMENT OF SIGNIFICANCE: In-situ gelling material is a promising strategy for intramyocardial hydrogel injection therapy for myocardial infarction (MI). Since the sol-gel transition of reported materials is driven by external stimulation such as temperature, pH, or ultraviolet, their application in vivo remains challenging. In this study, we first reported a synthetic in-situ gelling material (BAAm/PVA/S) whose gelation is stimulated by spontaneously reducing pre-added sorbitol after contacting the heart tissue. The BAAm/PVA/S solution spreads evenly, and is retained for at least 21 d in the heart tissue. Our study demonstrated that intramyocardial injection of the BAAm/PVA/S with more extensive distribution and longer retention had better effects on preventing LV dilation and improving cardiac function after MI than that of viscoelastic ALG and saline solution. We expect that these findings provide fundamental information for the optimum design of injectable biomaterials for treating MI.

A 67-year-old man was referred to our hospital for the diagnosis and treatment of prostate cancer. Multidisciplinary discussion led to intensity-modulated radiotherapy preceded by hormone therapy. Before radiotherapy, a biodegradable hydrogel spacer (HS) was placed between the prostate and rectum to reduce radiation injury risk. Three weeks postplacement, pelvic magnetic resonance imaging revealed HS migration into the pelvic vein. Subsequent whole-body contrast-enhanced computed tomography (CECT) revealed HS migration into the pulmonary artery. The patient showed no symptoms or clinical signs. Radiotherapy was completed uneventfully. Complete absorption of the migrated HS was confirmed using CECT images 5 months postplacement.

SpaceOAR, a polyethylene-glycol hydrogel, reduces rectal radiation exposure during radiation therapy for prostate cancer. Previously, our group reported the modified technique of hydrogel insertion, which achieves greater separated distance at prostate-apex. This study aimed to investigate the impact of separated distance at prostate-apex and our modifier technique, on radiation exposure reduction during proton beam therapy (PBT). We included 330 patients undergoing PBT with the relative biological effectiveness (RBE) of 63 Gray (Gy) for localized prostate cancer, and categorized them into groups 0 (no spacer, n = 141), 1 (separated distance of spacer at the prostate-apex level < 7.5 mm, n = 81), and 2 (distance ≥ 7.5 mm, n = 108). The rectal volumes to receive 30-60 Gy (RBE), was estimated and described as Rectal V30-60 (ml) in 10 Gy increments. The Rectal V30-60 (ml) was significantly lower in group 2 than in group 1, and in group 1 than in group 0. After propensity score matching, the multivariate logistic regression analysis revealed that the most significant factor to reduce radiation exposure was our modified technique of hydrogel insertion. Therefore, using a hydrogel spacer to expand the prostate-rectum distance not only at prostate-mid to prostate-base level but also at the prostate-apex level can reduce the radiation exposure in PBT for prostate cancer.

UNASSIGNED: Hydrogel spacers aim to separate the rectum from the prostate during radiation therapy for patients with prostate cancer to decrease the radiation dose and thus toxicity to the rectum. The aim of this study was to evaluate the distribution of the hydrogel spacer between the rectum and the prostate, to assess for hydrogel rectal wall infiltration and to assess for immediate complications.
UNASSIGNED: Retrospective study of 160 patients who had undergone hydrogel spacer placement. Distribution of the hydrogel was assessed on MRI. MRI images were reviewed for rectal wall injection or other malplacement of gel. Early post-procedure complications were recorded.
UNASSIGNED: 117 (73.1%) patients had a symmetrical distribution of the hydrogel spacer. The mean anteroposterior rectoprostatic separation was 10.2 ± 3.7 mm (range 0-27 mm). Seven (4.3%) patient had minimal rectal wall infiltration and one (0.6%) patient had moderate infiltration. One (0.6%) patient had an intraprostatic injection of hydrogel. Two (1.3%) patients required treatment in the emergency department: one for urinary retention and one for pain.
UNASSIGNED: Transperineal hydrogel placement separates the prostate from the rectum with a symmetrical distribution in the majority of cases prior to radiation therapy with a low rate of rectal wall injection and immediate complications.
UNASSIGNED: SpaceOAR hydrogel can be safely injected into radiation naive patients with low- or intermediate-risk organ-confined prostate cancer. The spacer separates the prostate from the rectum with a symmetrical distribution in the majority of cases prior to radiation therapy.

The physical and chemical properties of contact lenses (CLs) differ significantly from one another. This is already covered by the FDA classification, which divides soft lenses into groups and subgroups for additional characteristics. The differences relate to both the interior and surface of the lens. Several differences in the surface characteristics of individual contact lenses have been studied and demonstrated to date. However, one of their fundamental physical properties, that is light reflection or, quantitatively, reflectance has not been compared. This paper describes the surface differences of a range of silicone-hydrogel (SiHy) lenses using reflectance confocal microscopy. It shows the relationship between the amount of light reflected from the lens surface and the material parameters. Common SiHy lens materials were used in the study, including two lenses with surface modifications. Light incident at the interface between two media (phosphate-buffered saline and lens) with different refractive indices is partially reflected. The normalized results show significant differences between the reflection signals (1 vs 0.07), and that they are not correlated with the refractive index (R2 = 0.5536). For the water content (%H2O), a general trend was observed that the higher the %H2O, the lower the reflection signal is (R2 = 0.8105). The reflection signal and surface modulus show the best correlation. (R2 = 0.9883). The proposed CLs analysis method, using reflectance confocal microscopy, provides data to differentiate between lenses with and without surface modifications.

In the present research work, we intend to evaluate the effect of aging of CL (contact lenses) on friction and, in case there are alterations in the value of the coefficient of friction after aging, to understand which modifications in the material incite these variations. For this, a simulation of the aging process to which the CL are subject in vivo is carried out and the friction and stiffness of the CL are characterized, before and after aging. The aging procedure of SCLs (soft contact lenses) was simulated by a cycling process considering that the main parameter influencing the material surface is the transition between the closed and open eye and the exposure to environmental aggressions, particularly ultraviolet radiation. The values of the coefficient of friction and elastic modulus before and after the aging process were compared and was verified the increase of both parameters for all contact lenses. The hydrogel lens was the least affected by aging and the silicone - hydrogel lens based on delefilcon A was the one that showed the least stability of properties.