Intradermal Microdroplet Injection of Diluted Incobotulinumtoxin-A for Sebum Control, Face Lifting, and Pore Size Improvement.

BACKGROUND: Intradermal injections of botulinum toxin have been reported to improve sebum secretion, facial skin laxity, and facial pores. However, the effects of Incobotulinumtoxin-A for these indications have not been reported. OBJECTIVE: To evaluate the efficacy of Incobotulinumtoxin-A for the improvement of sebum secretion, face laxity, and facial pores. MATERIALS AND METHODS: This single-center retrospective study included patients treated with Incobotulinumtoxin-A to improve facial skin laxity, sebum secretion, and facial pores. The microdroplet injection protocol included injection points on the lateral face, anterior medial cheek, mandibular line, depressor anguli oris points, mid-glabella area, and chin. Outcomes were measured using a Sebumeter and three-dimensional scanner and were evaluated by facial laxity ratings and the Global Aesthetic Improvement Scale. RESULTS: Twenty patients were included in the analysis. Sebum secretion, mandibular length, facial pores, and facial laxity ratings were improved at 1 week and results were sustained through 12 weeks. All outcomes showed maximum improvement after 4 weeks. Evaluation using the Global Aesthetic Improvement Scale showed that all subjects reported at least a score of 2 (improved) after 4 weeks. CONCLUSION: This study showed that intradermal injection with Incobotulinumtoxin-A could be effective for face lifting, reduced sebum production, and improved facial pores. J Drugs Dermatol. 2021;20(1):49-54. doi:10.36849/JDD.5616.

Study on the Synthetic Characteristics of Biomass-Derived Isosorbide-Based Poly(arylene ether ketone)s for Sustainable Super Engineering Plastic.

Demand for the development of novel polymers derived from biomass that can replace petroleum resources has been increasing. In this study, biomass-derived isosorbide was used as a monomer in the polymerization of poly(arylene ether ketone)s, and its synthetic characteristics were investigated. As a phase-transfer catalyst, crown ether has increased the weight-average molecular weight of polymers over 100 kg/mol by improving the reaction efficiency of isosorbide and minimizing the effect of moisture. By controlling the experimental parameters such as halogen monomer, polymerization solvent, time, and temperature, the optimal conditions were found to be fluorine-type monomer, dimethyl sulfoxide, 24 h, and 155 °C, respectively. Biomass contents from isosorbide-based polymers were determined by nuclear magnetic resonance and accelerator mass spectroscopy. The synthesized polymer resulted in a high molecular weight that enabled the preparation of transparent polymer films by the solution casting method despite its weak thermal degradation stability compared to aromatic polysulfone. The melt injection molding process was enabled by the addition of plasticizer. The tensile properties were comparable or superior to those of commercial petrochemical specimens of similar molecular weight. Interestingly, the prepared specimens exhibited a significantly lower coefficient of thermal expansion at high temperatures over 150 °C compared to polysulfone.

Preparation of a nanocellulose/nanochitin coating on a poly(lactic acid) film for improved hydrolysis resistance.

Growing concerns regarding plastic waste have prompted various attempts to replace plastic packaging films with biodegradable alternatives such as poly(lactic acid) (PLA). However, their low hydrolysis resistance owing to the presence of aliphatic polyesters limits the shelf life of biodegradable polymers. Hydrolysis leads to the deterioration of mechanical performance, which is a key disadvantage of biodegradable plastics. In this study, a layer-by-layer (LBL) assembly method was used for the dip-coating of biorenewable, biodegradable nanocellulose/nanochitin on the PLA surface. Additional crosslinking and compression of the coated nanofibers, each containing carboxylic acid and amine groups, respectively, were induced through electromagnetic microwave irradiation to protect the PLA film by improving hydrolysis resistance. The coatings were examined by morphological observations and water contact angle measurements. The LBL coatings of differently charged nanofibers of 10.6 µm were reduced to 40 % after microwave treatment, and the thickness does not vary after the hydrolysis experiment. Microwave irradiation increased the water contact angle owing to amide linkage formation, thereby preventing the peeling off of coating layers. Improved hydrolysis resistance inhibited the reduction in molecular weight and tensile strength. These findings could be used to develop sustainable and biodegradable plastic packaging films with a prolonged shelf life.

Next-generation all-organic composites: A sustainable successor to organic-inorganic hybrid materials.

This Review presents an overview of all-organic nanocomposites, a sustainable alternative to organic-inorganic hybrids. All-organic nanocomposites contain nanocellulose, nanochitin, and aramid nanofibers as highly rigid reinforcing fillers. They offer superior mechanical properties and lightweight characteristics suitable for diverse applications. The Review discusses various methods for preparing the organic nanofillers, including top-down and bottom-up approaches. It highlights in situ polymerization as the preferred method for incorporating these nanomaterials into polymer matrices to achieve homogeneous filler dispersion, a crucial factor for realizing desired performance. Furthermore, the Review explores several applications of all-organic nanocomposites in diverse fields including food packaging, performance-advantaged plastics, and electronic materials. Future research directions-developing sustainable production methods, expanding biomedical applications, and enhancing resistance against heat, chemicals, and radiation of all-organic nanocomposites to permit their use in extreme environments-are explored. This Review offers insights into the potential of all-organic nanocomposites to drive sustainable growth while meeting the demand for high-performance materials across various industries.

Structural evaluation of Poly(lactic acid) degradation at standardized composting temperature of 58 degrees.

The accumulation of petroleum-based plastics on our planet is causing serious environmental pollution. Biodegradable plastics, promoted as eco-friendly solutions, hold the potential to address this issue. However, their impact on the environment and the mechanisms of their natural degradation remain inadequately understood. Furthermore, the specific conditions set forth in international standards for evaluating the biodegradability of biodegradable plastics have led to misconceptions about their real-world behavior. To properly elucidate the relationship between their degradability and structure, this study mimics the thermal effect on poly(lactic acid) (PLA) under standardized composting temperature. The higher the crystallinity of PLA, the lower the degradation rate, which suggests that crystallinity is a key factor in determining degradation. The composting temperature of 58 °C induces crystallization by having a structural effect on the polymer, which in turn reduces the degradation rate of PLA. Therefore, control over temperature and crystallization during the processing and degradation of PLA is crucial, as it not only determines the biodegradability but also enhances the utility.

Review of polymer technologies for improving the recycling and upcycling efficiency of plastic waste.

Human society has become increasingly reliant on plastic because it allows for convenient and sanitary living. However, recycling rates are currently low, which means that the majority of plastic waste ends up in landfills or the ocean. Increasing recycling and upcycling rates is a critical strategy for addressing the issues caused by plastic pollution, but there are several technical limitations to overcome. This article reviews advancements in polymer technology that aim to improve the efficiency of recycling and upcycling plastic waste. In food packaging, natural polymers with excellent gas barrier properties and self-cleaning abilities have been introduced as environmentally friendly alternatives to existing materials and to reduce food-derived contamination. Upcycling and valorization approaches have emerged to transform plastic waste into high-value-added products. Recent advancements in the development of recyclable high-performance plastics include the design of super engineering thermoplastics and engineering chemical bonds of thermosets to make them recyclable and biodegradable. Further research is needed to develop more cost-effective and scalable technologies to address the plastic pollution problem through sustainable recycling and upcycling.

Analysis of volatile organic compounds produced during incineration of non-degradable and biodegradable plastics.

As plastic consumption has increased, environmental problems associated with the accumulation of plastic wastes have started to emerge. These include the non-degradability of plastic and its disintegration into sub-micron particles. Although some biodegradable plastic products have been developed to relieve the landfill and leakage burden, a significant portion of discarded plastics are inevitably still incinerated. The concern here is that incinerating plastics may result in the emission of toxic volatile organic compounds (VOCs). Moreover, lack of policy and the limited market share contributes to the indiscriminate discarding of biodegradable plastics, whereby it is mixed and subsequently incinerated with non-degradable plastics. The aim of this study was therefore to qualitatively and quantitatively analyze the VOCs emitted from both non-degradable and biodegradable plastics during combustion employing gas chromatography mass spectrometry. Here, non-degradable poly(vinyl chloride) and poly(ethylene terephthalate) emitted 10-115 and 6-22 ppmv of VOCs, respectively. These emission levels were more than 100 times higher than the VOC concentrations of 0.1-0.5 and 0.1-1.8 ppmv obtained for biodegradable polyhydroxyalkanoate and polylactic acid, respectively. Notably, due to the presence of a repeating butylene group in both non-degradable and biodegradable plastics, 1,3-butadiene accounted for the highest concentration among the VOCs identified, with concentrations of 6-116 ppmv and 0.5-558 ppmv obtained, respectively. During the evaluation of gas barrier films employed for food packaging purposes, non-degradable aluminum-coated multilayered films emitted 9-515 ppmv of VOCs, compared to the 2-41 ppmv VOCs emitted by biodegradable nanocellulose/nanochitin-coated films. Despite the significantly lower levels of VOCs emitted during the incineration of biodegradable plastics, this does not represent suitable waste treatment solution because VOCs are still emitted during incomplete combustion. This study aims to encourage further research into diverse combustion conditions for plastics and stimulate discussions on the fate of discarded plastics.

Highly reinforced poly(butylene succinate) nanocomposites prepared from chitosan nanowhiskers by in-situ polymerization.

Biodegradable aliphatic polyesters need to be tough for commodity-plastic applications, such as disposable bags. Herein, we show that chitosan nanowhiskers (CsWs) prepared from naturally abundant chitin is an effective nanofiller that reinforces the strength and toughness of poly(butylene succinate) (PBS). In-situ polycondensation of an aqueous solution of processed CsWs led to a PBS nanocomposite with the highest tensile strength (77 MPa) and elongation at break (530%) reported to date for all PBS types at a minimal nanofiller content of 0.2 wt%. The observed 3.2-fold increase in toughness of the CsW/PBS composite compared to neat PBS is superior to those of composites prepared using cellulose nanocrystals, chitin nanowhiskers, and unstably dispersed CsWs in 1,4-butanediol monomer. Interestingly, CsWs efficiently overcome the disadvantages of the PBS film that easily tears. The highly polar surfaces of the CsWs strongly bind to polymer chains and promote a fibrillar and micro-void structure, thereby maximizing the chain-holding ability of the nanofiller, which resists external tensile and tear stress. This sustainable all-organic nanocomposite is a promising candidate for biodegradable disposable commodities.

Biorenewable, transparent, and oxygen/moisture barrier nanocellulose/nanochitin-based coating on polypropylene for food packaging applications.

Aluminum-coated polypropylene films are commonly used in food packaging because aluminum is a great gas barrier. However, recycling these films is not economically feasible. In addition, their end-of-life incineration generates harmful alumina-based particulate matter. In this study, coating layers with excellent gas-barrier properties are assembled on polypropylene films through layer-by-layer (LbL) deposition of biorenewable nanocellulose and nanochitin. The coating layers significantly reduce the transmission of oxygen and water vapors, two unfavorable gases for food packaging, through polypropylene films. The oxygen transmission rate of a 60 µm-thick, 20 LbL-coated polypropylene film decreases by approximately a hundredfold, from 1118 to 13.10 cc m-2 day-1 owing to the high crystallinity of nanocellulose and nanochitin. Its water vapor transmission rate slightly reduces from 2.43 to 2.13 g m-2 day-1. Furthermore, the coated film is highly transparent, unfavorable to bacterial adhesion and thermally recyclable, thus promising for advanced food packaging applications.

Chemo-Biological Upcycling of Poly(ethylene terephthalate) to Multifunctional Coating Materials.

Chemo-biological upcycling of poly(ethylene terephthalate) (PET) developed in this study includes the following key steps: chemo-enzymatic PET depolymerization, biotransformation of terephthalic acid (TPA) into catechol, and its application as a coating agent. Monomeric units were first produced through PET glycolysis into bis(2-hydroxyethyl) terephthalate (BHET), mono(2-hydroxyethyl) terephthalate (MHET), and PET oligomers, and enzymatic hydrolysis of these glycolyzed products using Bacillus subtilis esterase (Bs2Est). Bs2Est efficiently hydrolyzed glycolyzed products into TPA as a key enzyme for chemo-enzymatic depolymerization. Furthermore, catechol solution produced from TPA via a whole-cell biotransformation (Escherichia coli) could be directly used for functional coating on various substrates after simple cell removal from the culture medium without further purification and water-evaporation. This work demonstrates a proof-of-concept of a PET upcycling strategy via a combination of chemo-biological conversion of PET waste into multifunctional coating materials.

Malleable Hydrogel Embedded with Micellar Cargo-Expellers as a Prompt Transdermal Patch.

Although hydrogels are promising transdermal patches, they face spatiotemporal problems related to controlled drug release. From the "spatio" perspective, hydrogels are not malleable, therefore they do not fully contact curved skin, such as that found on the nose and fingers. From the "temporal" perspective, the internal network of a hydrogel retards cargo release. Herein, a malleable and rapid-cargo-releasing poly(vinyl alcohol)-borax hydrogel that embeds freely mobile poly(hydroxyethyl methacrylate) (PHEMA) micelles is prepared. The in situ polymerization of PHEMA within the matrix produces large compound micelle particles that are not bound by the matrix. The micelles act as expellers by sweeping out cargo upon exposure to wet conditions through a concentration gradient. The hydrogel embedded with the micellar cargo-expellers delivers a 25-fold larger 3-min release quantity of Nile Red (a model cargo) than the control hydrogel. The particles absorb mechanical shocks and the dynamic borate-diol bonds engender the hydrogel with self-healing properties, which results in a hydrogel that tightly contacts highly curved skin. Moreover, the hydrogel shows no toxicity in in vivo and skin irritation tests. This malleable hydrogel will inspire novel prompt skin-patch systems for pharmaceutical and cosmetics purposes.

A Self-Healing Nanofiber-Based Self-Responsive Time-Temperature Indicator for Securing a Cold-Supply Chain.

Perishable foods at undesired temperatures can generate foodborne illnesses that present significant societal costs. To certify refrigeration succession in a food-supply chain, a flexible, easy-to-interpret, damage-tolerant, and sensitive time-temperature indicator (TTI) that uses a self-healing nanofiber mat is devised. This mat is opaque when refrigerated due to nanofiber-induced light scattering, but becomes irreversibly transparent at room temperature through self-healing-induced interfibrillar fusion leading to the appearance of a warning sign. The mat monitors both freezer (-20 °C) and chiller (2 °C) successions and its timer is tunable over the 0.5-22.5 h range through control of the polymer composition and film thickness. The thin mat itself serves as both a temperature sensor and display; it does not require modularization, accurately measures localized or gradient heat, and functions even after crushing, cutting, and when weight-loaded in a manner that existing TTIs cannot. It also contains no drainable chemicals and is attachable to various shapes because it operates through an intrinsic physical response.

Highly self-healable and flexible cable-type pH sensors for real-time monitoring of human fluids.

Development of sensing technology with wearable chemical sensors is realizing non-invasive, real-time monitoring healthcare and disease diagnostics. The advanced sensor devices should be compact and portable for use in limited space, easy to wear on human body, and low-cost for personalized healthcare markets. Here, we report a highly sensitive, flexible, and autonomously self-healable pH sensor cable developed by weaving together two carbon fiber thread electrodes coated with mechanically robust self-healing polymers. The pH sensor cable showed excellent electrochemical performances of sensitivity, repeatability, and durability. Spontaneous and autonomous sensor healing efficiency of the pH sensor cable was demonstrated by measuring sensitivity during four cycles of cutting and healing process. The pH sensor cable could measure pH in small volumes of real human fluid samples, including urine, saliva, and sweat, and the results were similar to those of a commercial pH meter. Taken together, successful real-time pH monitoring for human sweat was demonstrated by fabricating a wearable sensing system in which the pH sensor cable was knitted into a headband integrated with wireless electronics.

Crab-on-a-Tree: All Biorenewable, Optical and Radio Frequency Transparent Barrier Nanocoating for Food Packaging.

Plastic packaging effectively protects foods from mechanical, microbial, and chemical damage, but oxygen can still permeate these plastics, degrading foods. Improving the gas barrier usually requires metallic or halogenated polymeric coatings; however, both cause environmental concerns and metallic coatings block visible light and electromagnetic signals. This paper reports a design of a highly flexible, visible light and radio frequency transparent coating on commercial poly(ethylene terephthalate) (PET) film. Nanoscale blending was achieved between negatively charged cellulose nanofibers and positively charged chitin nanowhiskers by employing spray-assisted layer-by-layer assembly. Synergetic interplay between these highly crystalline nanomaterials results in a flexible film with superior barrier characteristics. The oxygen transmission rate was below 0.5 mL m-2 day-1. Moreover, this coating maintains its performance even when exposed to common hazards such as bending stress and hydration. The coating also notably reduces the haziness of PET with a negligible loss of transparency and provides effective inhibition of antibacterial growth. This "crab-on-a-tree" nanocoating holds high potential for biorenewable and optical and radio frequency transparent packaging applications.

Extremely Fast Self-Healable Bio-Based Supramolecular Polymer for Wearable Real-Time Sweat-Monitoring Sensor.

Sensors with autonomous self-healing properties offer enhanced durability, reliability, and stability. Although numerous self-healing polymers have been attempted, achieving sensors with fast and reversible recovery under ambient conditions with high mechanical toughness remains challenging. Here, a highly sensitive wearable sensor made of a robust bio-based supramolecular polymer that is capable of self-healing via hydrogen bonding is presented. The integration of carbon fiber thread into a self-healing polymer matrix provides a new toolset that can easily be knitted into textile items to fabricate wearable sensors that show impressive self-healing efficiency (>97.0%) after 30 s at room temperature for K+/Na+ sensing. The wearable sweat-sensor system-coupled with a wireless electronic circuit board capable of transferring data to a smart phone-successfully monitors electrolyte ions in human perspiration noninvasively in real time, even in the healed state during indoor exercise. Our smart sensors represent an important advance toward futuristic personalized healthcare applications.

A ball milling-based one-step transformation of chitin biomass to organo-dispersible strong nanofibers passing highly time and energy consuming processes.

Chitin, a sustainable and functional biological macromolecule, can be converted into chitin nanofibers (ChNFs), and are applicable as a mechanically reinforcing and bioactive filler for polymer matrices. Improving the performance of ChNFs typically relies on their nanofibrilization and miscibility with matrices. To transform chitin biomass into organo-dispersible ChNFs, a series of time-/energy-consuming chemical and mechanical treatments are required: 1) deacetylation, 2) disintegration, 3) surface modification to minimize their aggregation through hydrogen bonds, 4) drying, and 5) re-dispersion. This paper presents a one-step method to transform chitin biomass to organo-dispersible acetylated ChNFs via a ball-milling method in the presence of relatively low toxic acetic anhydride without water. This method minimizes water contaminations and energy for dehydrating. The resulting chitin nanofiber material is mixed with poly(l­lactic acid) (PLLA) to produce all-bio-based nanocomposites. The composite indicated a 66% increase in Young's modulus and a 100% increase in tensile strength compared to the pristine PLLA. Furthermore, it did not exhibit any observable cytotoxic effect, thus potentially applicable as a biomedical material.

Y-shaped ligand-driven gold nanoparticles for highly efficient tumoral uptake and photothermal ablation.

We report functional gold nanoparticles (AuNP) with antibody-like ligands. These particles consist of Y-shaped ligands and AuNP. Transferrin (Tf) and Tat peptide were linked to each head of a Y-shaped poly(ethylene glycol) (PEG)-containing dopamine at one tail site. Also, Y-shaped ligands (with Tf and Tat peptide) were anchored to the surface of the AuNP as the result of noncovalent conjugation of dopamine and the AuNP. Interestingly, the partial shielding of Tat peptides by large Tf molecules rather improved Tf-mediated endocytosis of the AuNP, while minimizing the natural nonspecific cell interaction of Tat peptides. This system resulted in highly improved in vitro/in vivo tumor-selective uptake over AuNP bearing a single ligand (Tf or Tat peptides). Furthermore, this system resulted in significant enhancement of in vivo photothermal tumor cell ablation under light-irradiation conditions for AuNP. We believe that this design is a promising method to easily modify conventional antibodies or ligands to improve their disease-recognition ability.