Design of a UCST Polymer with Strong Hydrogen Bonds and Reactive Moieties for Facile Polymer-Protein Hybridization.

Polymer-protein hybrids have been extensively used in biomedical fields. Polymers with upper critical solution temperature (UCST) behaviors can form a hydrated coacervate phase below the cloud point (Tcp), providing themselves the opportunity to directly capture hydrophilic proteins and form hybrids in aqueous solutions. However, it is always a challenge to obtain a UCST polymer that could aggregate at a high temperature at a relatively low concentration and also efficiently bind with proteins. In this work, a UCST polymer reactive with proteins was designed, and its temperature responsiveness and protein-capture ability were investigated in detail. The polymer was synthesized by the reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylamide (AAm) and N-acryloxysuccinimide (NAS). Interestingly, taking advantage of the partial hydrolysis of NAS into acrylic acid (AAc), the obtained P(AAm-co-NAS-co-AAc) polymer exhibited an excellent UCST behavior and possessed good protein-capture ability. It showed a relatively higher Tcp (81 °C) at a lower concentration (0.1 wt %) and quickly formed polymer-protein hybrids with high protein loading and without losing protein bioactivity, and both the polymer and polymer-protein nanoparticles showed good cytocompatibility. All the findings are attributed to the unique structure of the polymer, which provided not only the strong and stable hydrogen bonds but also the quick and mild reactivity. The work offers an easy and mild strategy for polymer-protein hybridization directly in aqueous solutions, which may find applications in biomedical fields.

Poly(N-acryloyl glycinamide-co-N-acryloxysuccinimide) Nanoparticles: Tunable Thermo-Responsiveness and Improved Bio-Interfacial Adhesion for Cell Function Regulation.

Poly(N-acryloyl glycinamide) (PNAGA) can form high-strength hydrogen bonds (H-bonds) through the dual amide motifs in the side chain, allowing the polymer to exhibit gelation behavior and an upper critical solution temperature (UCST) property. These features make PNAGA a candidate platform for biomedical devices. However, most applications focused on PNAGA hydrogels, while few focused on PNAGA nanoparticles. Improving the UCST tunability and bio-interfacial adhesion of the PNAGA nanoparticles may expand their applications in biomedical fields. To address the issues, we established a reactive H-bond-type P(NAGA-co-NAS) copolymer via reversible addition-fragmentation chain transfer polymerization of NAGA and N-acryloxysuccinimide (NAS) monomers. The UCST behaviors and the bio-interfacial adhesion toward the proteins and cells along with the potential application of the copolymer nanoparticles were investigated in detail. Taking advantage of the enhanced H-bonding and reactivity, the copolymer exhibited a tunable UCST in a broad temperature range, showing thermo-reversible transition between nanoparticles (PNPs) and soluble chains; the PNPs efficiently bonded proteins into nano-biohybrids while keeping the secondary structure of the protein, and more importantly, they also exhibited good adhesion ability to the cell membrane and significantly inhibited cell-specific propagation. These features suggest broad prospects for the P(NAGA-co-NAS) nanoparticles in the fields of biosensors, protein delivery, cell surface decoration, and cell-specific function regulation.

H-bond-type thermo-responsive schizophrenic copolymers: The phase transition correlation with their parent polymers and the improved protein co-assembly ability.

Schizophrenic copolymers are one type of the popular smart polymers that show invertible colloidal structures in response to temperature stimulus. However, the lack of principles to predict the phase transition temperature of a schizophrenic copolymer from its corresponding parent thermo-responsive polymers limits their development. Additionally, studies on their applications remain scarce. Herein, a series of schizophrenic copolymers were synthesized by polymerization of a RAFT-made polymer precursor poly(acrylamide-co-N-acryloxysuccinimide-co-acrylic acid) (P(AAm-co-NAS-co-AAc)) with the mixture of N-isopropylmethacrylamide (NIPAm) and acrylamide (AAm) in varying molar ratios. In aqueous solution, the block P(AAm-co-NAS-co-AAc) and the block poly(NIPAm-co-AAm) exhibited upper and lower critical solution temperature (UCST and LCST) behavior, respectively. The schizophrenic copolymers featured either UCST-LCST, LCST-UCST, or only LCST thermo-responsive transition. A preliminary correlation of phase transition between the schizophrenic copolymers and their parent polymers was summarized. Furthermore, the co-assembly of the schizophrenic copolymers and proteins were conducted and the kinetics of protein loading and protein activity were investigated, which showed that the schizophrenic copolymers were efficient platforms for protein co-assembly with ultra-high protein loading while preserving the protein bioactivities. Additionally, all the materials were non-toxic towards NIH 3T3 and MCF-7 cells. This work offers the prospects of the schizophrenic polymers in soft colloidal and assembly systems, particularly in guiding the design of new materials and their use in biomedical applications.

Application of Nonsurgical Modalities in Improving Facial Aging.

OBJECTIVE: This review aims to summarize different kinds of applications of minimally invasive surgery in improving facial aging to provide a comprehensive and accurate introduction on the issue of esthetic treatment of facial skin. Overview. In the twentieth century, facial rejuvenation has become a new beauty trend. Facial cosmetology has entered a period of antiaging and rejuvenation therapies and microplastic surgery. The pursuit of beauty has promoted the development of minimally invasive plastic surgery. This review introduces the possible causes of facial aging and its related topics with a focus on facial injectable drugs, such as botulinum toxin, main filler materials (hyaluronic acid, calcium hydroxyapatite, poly L-lactic acid, collagen, autologous fat, and polymethyl methacrylate), and some current antiwrinkle technologies, such as thread lift and radiofrequency rhytidectomy. CONCLUSIONS: Despite the difference in mechanisms of action, each technique can address facial aging involving the loss of collagen, displacement and enlargement of fat, and muscle relaxation. Combinations of these treatments can provide patients with reasonable, comprehensive, and personalized treatment plans.

Analysis of Three-Dimensional Morphological Differences in the Mandible between Skeletal Class I and Class II with CBCT Fixed-Point Measurement Method.

This study was aimed at determining the three-dimensional differences in the mandible morphology between skeletal class I and II patients, at exploring the pathogenic mechanisms and morphological characteristics of skeletal class II, and at providing clinical references. The subjects were assigned to two groups according to the size of ANB angle: skeletal class I (2° < ANB angle < 5°) and skeletal class II (5° < ANB angle < 8°). After cone-beam computed tomography (CBCT) scanning, 31 landmarks and 25 measurement items were determined by In Vivo Dental 5.1 software (Anatomage, CA) for statistical analysis. The results were as follows: Co-Go, Go-Me, and CdM-CdD in skeletal class II cases were smaller than those in skeletal class I, and GoR-Me-GoL, GoR-Me-CoL, and, Ig-Men were larger than those in skeletal class I cases. In conclusion, there were significant differences in the three-dimensional morphology of the mandible between skeletal class I and class II patients. The vertical growth of the ramus, the horizontal growth of the mandibular body, and the condyle in skeletal class II patients were smaller than those in skeletal class I cases. In skeletal class II, the growth of the anterior part of the mandible in the vertical direction was larger than that in skeletal class I, and the shape of the mandible was more extended.

A Review of 3D Printing in Dentistry: Technologies, Affecting Factors, and Applications.

Three-dimensional (3D) printing technologies are advanced manufacturing technologies based on computer-aided design digital models to create personalized 3D objects automatically. They have been widely used in the industry, design, engineering, and manufacturing fields for nearly 30 years. Three-dimensional printing has many advantages in process engineering, with applications in dentistry ranging from the field of prosthodontics, oral and maxillofacial surgery, and oral implantology to orthodontics, endodontics, and periodontology. This review provides a practical and scientific overview of 3D printing technologies. First, it introduces current 3D printing technologies, including powder bed fusion, photopolymerization molding, and fused deposition modeling. Additionally, it introduces various factors affecting 3D printing metrics, such as mechanical properties and accuracy. The final section presents a summary of the clinical applications of 3D printing in dentistry, including manufacturing working models and main applications in the fields of prosthodontics, oral and maxillofacial surgery, and oral implantology. The 3D printing technologies have the advantages of high material utilization and the ability to manufacture a single complex geometry; nevertheless, they have the disadvantages of high cost and time-consuming postprocessing. The development of new materials and technologies will be the future trend of 3D printing in dentistry, and there is no denying that 3D printing will have a bright future.

Design of a Single-Tooth Model and Its Application in Oral Scan System Assessment.

Intraoral scanners have been widely used in the application of dentistry. Accuracy includes trueness and precision; they have an important position in the assessment of intraoral scanners. The existing standard models are divided into the inlay and the crown, but the operation is relatively complicated. In this study, in order to simplify the current standard model, we designed a new integration model to compare the accuracy of two intraoral scanners (CEREC and TRIOS) and an extraoral scanner (SHINING). The coordinate measuring machine measured value is the gold standard. Values of the length and angle were analyzed by converting the scanned digital impressions into an STL (standard triangulation language) format to evaluate the accuracy of the intraoral scanner and to verify the feasibility of the designed model. The result shows that the integration model can be successfully scanned and imaged. In the case of the powder-free integration model, intraoral scanner precision, trueness, 3D fitting, and imaging are better than the extraoral scanner. It can be seen straightly from the measurement result and the 3D fitting result that the intraoral scanner can acquire the shape of the standard model integrally with good repeatability. Therefore, it can be concluded that TRIOS is superior to CEREC and SHINING in accuracy, and the integration model is feasible as a reference in the examination of intraoral scanners. The performance of the newly designed integration model that can be scanned is clinically significant, suggesting that this model can be used as a standard reference model.