Force degradation study on aligner plates immersed in various solutions.

Background/purpose: The strength of aligners themselves has a high decay rate and is susceptible to accelerated degradation in the environment. The purpose of this study was to compare three types of invisible aligner films after being immersed in coffee, tea, cola, and red wine for seven days and to evaluate the changes in their strengths. Materials and methods: Three types of invisible aligner plates with a thickness of 0.75 mm, i.e., Duran T (polyethylene terephthalate glycol, PETG), Biolon (polyethylene terephthalate, PET), and Zendura FLX (polyurethane, PU), were soaked in artificial saliva and four drinks (coffee, tea, cola, red wine) for 1, 4, and 7 days. The strength test was performed by using the three-point bending test method. The residual strength ratio for the same type of invisible correction film at the same time was separately recorded. The independent t-test was used to indicate significant differences at P < 0.05. Results: The Biolon invisible correction film soaked in cola, red wine and artificial saliva showed significant differences on the 1st and 4th days (P < 0.05). The Duran T invisible correction film soaked in coffee and artificial saliva showed significant differences on the first day (P < 0.05). The Zendura FLX invisible correction film had a waterproof layer on the surface, and there was no significant difference between soaking in any drink and soaking in saliva (P > 0.05). Conclusion: Invisible correction films with different ingredients soaked in solutions show a strength decay phenomenon, except for those with TPU ingredients.

An in vitro evaluation of aligner force decay in artificial saliva.

Background/purpose: The present study aimed to compare the force decay of invisible aligners for maxillary anterior teeth with 0.1 mm (D1), 0.2 mm (D2), and 0.3 mm (D3) labial movement within a simulated oral environment over 7 days. Materials and methods: The prepared invisible aligners were immersed in saliva (S) and subjected to applied force (F) for 7 days. The aligners were set and placed on the maxillary right central incisor with 0.1 mm (D1), 0.2 mm (D2), and 0.3 mm (D3) labial movement. Thin-film pressure sensors were used to measure the aligner force changes. The data were collected and analyzed by statistical methods. Results: Significant differences were observed in the initial and first-day force between the D2 and D3 groups under simulated oral environment force (SF) (P < 0.05). There was a significant difference in force decay between Day 1 and Day 7 for all groups (P < 0.05). The SFD1 group showed a significant decrease in force on Day 5 (P < 0.05), while the SFD2 and SFD3 groups showed significant force decay on Day 4 (P < 0.05). The force decay ratio on Day 7 was higher in the SFD3 group than in the SFD1 and SFD2 groups, but no significant difference was observed. Conclusion: Larger labial movement of the aligners resulted in higher force decay under artificial saliva environments, and the force decay of invisible aligners was increased by immersion time in artificial saliva.

Immobilization of sulfur in microgels for lithium-sulfur battery.

Immobilization of sulfur in microgels is achieved via free radical polymerization of commercial poly(ethylene glycol) dimethacrylate in the solution of sulfur-terminated poly(3-oligo(ethylene oxide)4-thiophene), a copolymer prepared by the inverse vulcanization of S8 with allyl-terminated poly(3-oligo(ethylene oxide)4-thiophene). This microgelation leads to enhanced Li-S battery performance over the sulfur-terminated polymer.

A nanogel of on-site tunable pH-response for efficient anticancer drug delivery.

A smart, soft and small nanoparticulate drug carrier that can efficiently transport therapeutics into tumor cells to control the intracellular drug concentration will enable major advancements in cancer therapy. To facilitate a remote modulation of the intracellular pH-regulated drug release, we have designed a new class of pH-responsive chitosan-based nanogels (<200 nm) by the physical interpenetration of chitosan chains into a nonlinear poly(ethylene glycol) (nonlinear PEG) chain network. The resultant PEG-chitosan nanogels not only respond to the changes in environmental pH over the physiologically important range of 5.0-7.4, but - more importantly - also enable us to remotely modulate the pH response by external cooling/heating. The nanogel, as well as the nanogel loaded with a model anticancer drug 5-fluorouracil (5-FU), is capable of varying its surface charge from nearly neutral to positive around tumor extracellular pH (~6.0-6.2) to facilitate cell internalization. Subsequently, the significantly increased acidity in subcellular compartments (~5.0) can trigger 5-FU release from the endocytosed drug carriers. While this nanogel serving as a drug carrier exhibits a reduced toxicity in combined chemo-thermo treatments, it has shown significantly enhanced therapeutic efficacy in combined chemo-cryo treatments of the model B16F10 melanoma cells, indicating its great potential for cancer therapy.

One-pot synthesis of responsive catalytic Au@PVP hybrid nanogels.

Responsive catalytic hybrid nanogels with Au nanoparticle cores and a polyvinylpyrrolidone (PVP) based gel shell are prepared through a novel one-pot approach. The embedded Au nanoparticles demonstrate both a pH-modulated catalytic activity and anti-aggregation properties upon recycling.

A fluorescent responsive hybrid nanogel for closed-loop control of glucose.

BACKGROUND: The concept of closed-loop control of glucose, in which continuous glucose sensing is coupled to a fully automated insulin delivery device, without human input, has been an attractive idea for diabetes management. This study presents a new class of hybrid nanogels that can integrate glucose sensing and glucose-responsive insulin release into a single nano-object. METHODS: Zinc oxide@poly[N-isopropylacrylamide (NIPAM)-acrylamide (AAm)- 2-aminomethyl-5-fluorophenylboronic acid (FPBA)] hybrid nanogels were synthesized and investigated for size, morphology, volume phase transition, photoluminescence properties, and in vitro insulin release under different glucose concentrations. Glucose sensing was performed both in phosphate-buffered saline (PBS) and in blood samples. The insulin release in PBS of varying glucose levels, as well as a stepwise treatment between two glucose levels (126.0 and 270.0 mg/dl), was performed to test the glucose-responsive insulin release ability of the hybrid nanogels. RESULTS: Zinc oxide@poly(NIPAM-AAm-FPBA) hybrid nanogels can sensitively and selectively detect glucose in highly reproducible fluorescent signals over the clinically relevant glucose concentration range of 18-540 mg/dl. The glucose-responsive volume phase transition of the nanogels can further regulate the release of the preloaded insulin. The insulin release from the nanogels exhibits the slowest rate (~5% released in 76 h) at a normal glucose level (108.0 mg/dl) but becomes quicker and quicker as the glucose increases to higher and higher levels. CONCLUSIONS: The rationally designed hybrid nanogel can optically signal the glucose level with high sensitivity and selectivity and simultaneously regulate the insulin release rate in response to the glucose reading, which shows a promising concept toward the development of a miniaturized closed-loop glycemic control system.