The Efficiency of Segmental Le Fort I Surgery in Clear Aligner Therapy of Skeletal Class III Deformity: A Pilot Study.

INTRODUCTION: The purpose of this study was to investigate the efficiency of segmental Le Fort I osteotomy in clear aligner therapy of skeletal Class III deformities and to explore whether Le Fort I segmental osteotomy was effective for maxillary incisor axis correction and reduced the duration of perioperative orthodontics. MATERIALS AND METHODS: Patients who had skeletal Class III deformities (ANB<0) treated with extraction of the maxillary first premolars, segmental Le Fort I osteotomy, and clear aligners therapy were included in this retrospective study. We measured the amount of tooth extraction space that was closed by surgery and recorded the preoperative orthodontic and total treatment duration. Lateral cephalograms were analyzed to measure changes of maxillary incisor inclination before treatment (T0), 1 week before surgery (T1), 1 week after surgery (T2), and after total orthodontic treatment (T3). Statistical analyses were performed, and the P value was set at 0.05. RESULTS: The sample was composed of 15 patients aged 19 to 30 (M=22.9) years. The average preoperative orthodontic treatment duration was 16.2±5.22 mo, with 33.5 pairs of clear aligners. The gap at the extraction site decreased from 5.42±1.57 mm to 0.80±0.62 mm on average after surgery. U1-SN and U1-NA(deg) increased sparingly with preoperative decompensation, decreased in quantity after surgery, and then slightly increased with postoperative compensation (T20.05). CONCLUSIONS: Le Fort I segmental osteotomy assisted decompensation of the upper anterior teeth and reduced the duration of preoperative orthodontics with clear aligners.

Preparation of cellulose-based flexible SERS and its application for rapid and ultra-sensitive detection of thiram on fruits and vegetables.

In response to the prevalent issue of thiram as a common pesticide residue on the surface of fruits and vegetables, our research team employed an acidic hydrated metal salt low co-fusion solvent to dissolve cellulose lysis slurry. Subsequently, a regenerated cellulose membrane (RCM) was successfully prepared via sol-gel method. Uniformly sized Ag nanoparticles (NPs) were deposited on RCM utilizing the continuous ion layer adsorption and reaction (SILAR) technique. The resulting Ag NPs/RCM flexible surface-enhanced Raman spectroscopy (SERS) substrates exhibited a minimum detection limit of 5 × 10-9 M for Rhodamine 6G (R6G), demonstrating good uniformity (RSD = 4.86 %) and reproducibility (RSD = 3.07 %). Moreover, the substrate displayed a remarkable sensitivity of 10-10 M toward thiram standard solution. Given its inherent flexibility, the substrate proves advantageous for the detection of three-dimensional environments such as fruit and vegetable surfaces, and its practicality has been confirmed in the detection of thiram residue on apples, tomatoes, pears, and other fruits and vegetables.

Cryogenic 3D printing of modified polylactic acid scaffolds with biomimetic nanofibrous architecture for bone tissue engineering.

The individualized polylactic acid (PLA) scaffolds fabricated by 3D printing technique have a good application prospect in the bone tissue engineering field. However, 3D printed PLA scaffold mainly manufactured by using a Fused Deposition Modelling fabrication technique (FDM) has some disadvantages, such as having smooth surface, strong hydrophobicity, poor cell adhesion, undesirable bioactivity, the degradation and deterioration at a high temperature triggering an inflammatory response. In this work, the aminated modified polylactic acid nanofibrous scaffold prepared by cryogenic 3D printing technology is designed to provide a feasible countermeasure to solve the key problems existing at present. The prepared scaffolds were fully characterized in terms of physico-chemical and morphological analyses, and the collected results revealed that the using of the cryogenic 3D printing technology can effectively avoid the degradation and deterioration of PLA at a high temperature required by FDM technique and promote the formation of nanofibrous structures. The in vitro tests with MC3T3-E1 cells confirmed that the cell-responsive biomimetic fibrous architecture and improved hydrophilicity due to the introduction of hydrophilic active amino groups provided a bioactive interface for cell adhesion and growth. Meanwhile, the active amino groups introduced by ammonolysis reaction can act as active sites for biomineralization. Thus, the as-prepared scaffolds may hold great potential for bone tissue engineering applications.

Highly Transparent, Self-Healing, and Self-Adhesive Double Network Hydrogel for Wearable Sensors.

Hydrogel-based flexible electronic devices are essential in future healthcare and biomedical applications, such as human motion monitoring, advanced diagnostics, physiotherapy, etc. As a satisfactory flexible electronic material, the hydrogel should be conductive, ductile, self-healing, and adhesive. Herein, we demonstrated a unique design of mechanically resilient and conductive hydrogel with double network structure. The Ca2+ crosslinked alginate as the first dense network and the ionic pair crosslinked polyzwitterion as the second loose network. With the synthetic effect of these two networks, this hydrogel showed excellent mechanical properties, such as superior stretchability (1,375%) and high toughness (0.57 MJ/m3). At the same time, the abundant ionic groups of the polyzwitterion network endowed our hydrogel with excellent conductivity (0.25 S/m). Moreover, due to the dynamic property of these two networks, our hydrogel also performed good self-healing performance. Besides, our experimental results indicated that this hydrogel also had high optical transmittance (92.2%) and adhesive characteristics. Based on these outstanding properties, we further explored the utilization of this hydrogel as a flexible wearable strain sensor. The data strongly proved its enduring accuracy and sensitivity to detect human motions, including large joint flexion (such as finger, elbow, and knee), foot planter pressure measurement, and local muscle movement (such as eyebrow and mouth). Therefore, we believed that this hydrogel had great potential applications in wearable health monitoring, intelligent robot, human-machine interface, and other related fields.

Multifunctional modified polylactic acid nanofibrous scaffold incorporating sodium alginate microspheres decorated with strontium and black phosphorus for bone tissue engineering.

Polylactic acid (PLA) nanofibrous scaffolds have received extensive attention in the field of tissue engineering due to their excellent degradability, biocompatibility and the biomimetic extracellular matrix (ECM) topographies. However, the cell affinity and osteogenic activity of PLA scaffolds is not satisfactory because of their intrinsic hydrophobicity, the absence of cell recognition sites and the nucleation sites of the in vivo biomineralization. Furthermore, effective anti-inflammatory activity for the in vivo scaffold could not be ignored, so a strategy to develop a multifunctional PLLA (poly-L-lactic acid) nanofibrous scaffold with improved hydrophilicity, osteoinductivity, excellent near-infrared photothermal-responsive drug release capacity and anti-inflammatory activity via incorporating sodium alginate microspheres decorated with strontium and ibuprofen-loaded black phosphorus (BP + IBU@SA microspheres) into aminated modified PLLA nanofiber network is proposed in this study. Scanning electron microscopy (SEM) observation showed that the BP + IBU@SA microspheres were homogeneously dispersed into the modified PLLA matrix with uniform nanofiber structure and the chemical composition of the as-prepared scaffolds was confirmed by X-ray diffraction analysis (XRD) and elemental mapping. The photothermal property of the scaffolds was assessed under near-infrared (NIR) light irradiation, the results manifested that the entrapment of BP nanosheets endowed PLLA nanofibrous scaffold with significantly high photothermal conversion efficiency and optical cycle stability. Meanwhile, the scaffold also displayed an excellent photothermal-responsive intelligent drug release performance toward Sr2+ and ibuprofen. Moreover, the in vitro studies revealed that the as-developed scaffolds possessed a good biocompatibility for cell adhesion and proliferation and an improved bioactivity to induce apatite formation. All these results indicated the potential of the fabricated scaffolds in tissue engineering applications.

Controllable Drug Delivery by Na+/K+ ATPase α1 Targeting Peptide Conjugated DSPE-PEG Nanocarriers for Breast Cancer.

Although Epirubicin (EPI) is a commonly used anthracycline for the treatment of breast cancer in clinic, the serious side effects limit its long-term administration including myelosuppression and cardiomyopathy. Nanomedicines have been widely utilized as drug delivery vehicles to achieve precise targeting of breast cancer cells. Herein, we prepared a DSPE-PEG nanocarrier conjugated a peptide, which targeted the breast cancer overexpression protein Na+/K+ ATPase α1 (NKA-α1). The nanocarrier encapsulated the EPI and grafted with the NKA-α1 targeting peptide through the click reaction between maleimide and thiol groups. The EPI was slowly released from the nanocarrier after entering the breast cancer cells with the guidance of the targeting NKA-α1 peptide. The precise and controllable delivery and release of the EPI into the breast cancer cells dramatically inhibited the cells proliferation and migration in vitro and suppressed the tumor volume in vivo. These results demonstrate significant prospects for this nanocarrier as a promising platform for numerous chemotherapy drugs.

Biomimetic mineralization of nanocrystalline hydroxyapatites on aminated modified polylactic acid microspheres to develop a novel drug delivery system for alendronate.

EPLA/nHAp composite microsphere, a novel drug delivery system potentially useful for the local delivery of alendronate (AL) to bone tissue was developed via the biomimetic mineralized deposition of nano-hydroxyapatite (nHAp) crystals on the surface of aminated modified polylactic acid (EPLA) microspheres. Scanning electron microscopy (SEM) observation showed that this system consisted of a polymer core with nanofiber network structure and inorganic coating composed of countless rod-like nanocrystalline particles, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) confirmed that these particles were nHAp crystals. An efficient AL-loading can be realized by facile impregnation-adsorption method under suitable conditions due to the high adsorption capacity of EPLA/nHAp composite microspheres. The drug loading efficiency of microspheres was detected by indirect ultraviolet spectrophotometry. It was found that the adsorption capacity of EPLA/nHAp composite microsphere towards AL was increased nearly 5-fold compared with that of bare EPLA microspheres owing to the strong interaction between alendronate and hydroxyapatite. Meanwhile, in vitro release study showed that AL-loaded EPLA/nHAp microspheres had a more sustained drug release than AL-loaded EPLA microspheres, all these results demonstrated that the as-prepared EPLA/nHAp composite microsphere is an efficient carrier for the delivery and sustained release of AL. Furthermore, an in vitro cell culture study revealed that these composite microspheres presented a good biocompatibility, showing great potential for the applications in the biomedical field.

Preparation and characterization of hydroxyapatite/polycaprolactone-chitosan composites.

Hydroxyapatite (HA)/polycaprolactone (PCL)-chitosan (CS) composites were prepared by melt-blending. For the composites, the amount of HA was varied from 0% to 30% by weight. The morphology, structure and component of the composites were evaluated using environmental scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscope. The tensile properties were evaluated by tensile test. The bioactivity and degradation property were investigated after immersing in simulated body fluid (SBF) and physiological saline, respectively. The results show that the addition of HA to PCL-CS matrix tends to suppress the crystallization of PCL but improves the hydrophilicity. Adding HA to the composites decreases the tensile strength and elongation at break but increases the tensile modulus. After immersing in SBF for 14 days, the surface of HA/PCL-CS composites are covered by a coating of carbonated hydroxyapatite with low crystallinity, indicating the excellent bioactivity of the composites. Soaking in the physiological saline for 28 days, the molecular weight of PCL decreases while the mass loss of the composites and pH of physiological saline increase to 5.86% and 9.54, respectively, implying a good degradation property of the composites.

Fabrication and characterization of poly (ethylenimine) modified poly (l-lactic acid) nanofibrous scaffolds.

Bone tissue engineering aims to construct biological substitutes for repairing bone defects. Nanofibrous (NF) scaffolds are commonly utilized to mimic the extracellular matrix (ECM) environment and promote tissue regeneration in tissue engineering process. Poly (lactic acid) (PLA) has attracted much attention in the field of tissue engineering because of its biocompatibility, biodegradability and so on. However, the intrinsic hydrophobicity and the lacking of active functional groups limit its practical application to some extent. In this study, poly(ethylenimine) (PEI) modified PLLA nanofibrous scaffolds were fabricated in a one step process by aminolysis combined with thermally induced phase separation technique for introducing more functional groups, PEI acting as the modifier. The morphology of PEI-modified PLLA scaffolds prepared under different experimental conditions was analyzed by scanning electron microscope (SEM). The suitable conditions to fabricate scaffolds with a homogeneous nanofibrous structure, good hydrophilicity and excellent mechanical properties were determined according to the results of SEM, water contact angle (WCA) and mechanical properties testing. Besides, Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), X-ray Photoelectron Spectroscopy (XPS) and gel permeation chromatography (GPC) were used to confirm the occurrence of the ammonolysis reaction between PLLA and PEI. The in vitro biomineralization study showed that the PEI-modified PLLA scaffolds had a greater ability to induce the formation of apatite in 1.5SBF than PLLA scaffolds, indicating that the bone-bioactivity of PLLA scaffolds was significantly improved after modification with PEI. Furthermore, cell culture assay revealed that MC3T3-E1 osteoblasts exhibited better proliferation performance on the PEI-modified PLLA scaffolds. All the results implied that the synthesized modified PLLA nanofibrous scaffolds may provide promising applications in bone tissue engineering.

[Biological properties and formation of electrodeposited HA-Ti/HA composite coatings].

In order to improve the bonding strength of the hydroxyapatite (HA) coatings on the metal substrate, we prepared the HA-Ti/HA composite coatings by two-step electrodeposited method, and then we studied the component, microstructure, surface morphologies and the bonding strength of the HA-Ti/HA composite coatings. SBF test and cell culture in vitro were carried out to evaluate the biological properties of the composite coatings. The results showed that the bonding strength of the HA-Ti/HA composite coating (Ti, 51.2wt%) was as high as 21.2 MPa which was 3 times that of pure HA coatings. The coatings' surface was covered by carbonate-apatite layer after being immersed in SBF, and the bone marrow cells attached firmly and proliferated well on the surface of composite coatings. These findings indicate that the composite coatings possess good bioactivity and excellent biocompatibility.

Fabrication and characterization of modified nanofibrous poly(L-lactic acid) scaffolds by thermally induced phase separation technique and aminolysis for promoting cyctocompatibility.

Modified nanofibrous Poly(L-lactic acid) (PLLA) scaffolds were fabricated by aminolysis combined with thermally induced phase separation technique using PLLA/1,4-dioxane/urea-NaOH-H2O system at -40 °C freeze temperature. Aminolysis led to the modification of scaffold resulting in enhancement in the bioactivity. The surface of the modified nanofibrous scaffold provided a good environment for attachment and proliferation of MC3T3-E1 subclone 14 cells, exhibiting significant potential for bone tissue regeneration and for promoting cytocompatibility.

Fabrication of polycaprolactone nanofibrous scaffolds by facile phase separation approach.

Three-dimensional polycaprolactone (PCL) scaffolds with spherulite and nanofibrous structures were fabricated for the first time by thermally induced phase separation from a ternary PCL/dioxane/water system. Moreover, the effects of polymer concentration, aging temperature and the ratio of dioxane to water on the morphology of nanofibrous scaffolds were investigated. The result revealed that gelation, aging temperature, and ratio of solvents significantly influenced the formation of the unique spherulite and nanofibrous structures. The apatite-formation ability test showed relatively rapid growth of carbonate hydroxyapatite in the nanofibrous PCL scaffold with macropore compared to the other two scaffolds with smooth structure and nanofibrous structure without macropore, respectively, indicating good apatite-formation ability of the macroporous and nanofibrous PCL scaffolds.

Electrophoretic deposition of silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings.

Silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings were prepared on titanium substrate by electrophoretic deposition in n-butanol and chloroform mixture. The effect of the concentration of poly(epsilon-caprolactone) in suspension on the morphology and the microstructure of coatings were investigated, furthermore, the thermal behavior and in vitro bioactivity were also investigated. The results show that the coarse and accidented silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings were obtained by electrophoretic deposition when the concentration of poly(epsilon-caprolactone) in suspension was 6-16 g/l. The adsorption of poly(epsilon-caprolactone) on the surface of Si-HA particles hinders the electrophoretic deposition of Si-HA. The shear-testing experiments indicated that the addition of poly(epsilon-caprolactone) in suspension is in favor of improving the bonding strength of the coatings. After immersion in simulated body fluid for 8 days, silicon-substituted hydroxyapatite/poly(epsilon-caprolactone) composite coatings have the ability to induce the bone-like apatite formation.

Preparation and characterization of nano-hydroxyapatite/polymer composite scaffolds.

Polycaprolactone/chitosan (PCL/CS) porous composite scaffolds were prepared by solution phase separation method, and the scaffolds were further enhanced by filling with nano-hydroxyapatite/polyvinyl alcohol (n-HA/PVA) composite slurry to prepare n-HA-PVA/PCL-CS composite porous scaffolds through slurry centrifugal filling technique. The morphology, microstructure, component, porosity and mechanical property of the scaffolds were characterized using scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscope, elemental analyzer and material test machine. The results show that PCL/CS scaffolds have mutual transfixion porous structure just like honeycombs. The porosity of the scaffolds can achieve 60-80%. As the content of CS increases, the porosity increases while the compressive strength decreases. After filled with HA/PVA composite slurry, the porosity of n-HA/PCL-CS composite scaffolds decreases, but still greater than 60%, while the compression modulus can increase to 25.7 MPa.

Structural characterization of zinc-substituted hydroxyapatite prepared by hydrothermal method.

Zinc-substituted hydroxyapatite (Zn-HA) powders were prepared by hydrothermal method using Ca(NO(3))(2), (NH(4))(3)PO(4) and Zn(NO(3))(2 )as reagents. X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) were used to characterize the crystalline phase, microstructure, chemical composition, morphology and thermal stability of Zn-HA. The results show that the substitution content of zinc (Zn) in Zn-HA powders prepared in NaOH solution is higher than that prepared in NH(3) solution, and is lower than that of the corresponding amount of starting materials. The substitution of the Zn ion for calcium ion causes a lower crystallinity of Zn-HA and changes the lattice parameters of Zn-HA, since the ionic radius is smaller in Zn(2+) (0.074 nm) than in Ca(2+ )(0.099 nm). Furthermore, the substitution of the Zn ions restrains the growth of Zn-HA crystal and decreases the thermal stability of Zn-HA. Zn-HA powder prepared in NH(3) solution starts to decompose at 800 degrees C when the Zn fraction increases to 15 mol%, while that prepared in NaOH solution start to decompose at 5 mol% Zn. The substitution content of Zn significantly influences the thermal stability, microstructure and morphology of Zn-HA.