Count Me in, Count Me out: Regulation of the Tooth Number via Three Directional Developmental Patterns.

Tooth number anomalies, including hyperdontia and hypodontia, are common congenital dental problems in the dental clinic. The precise number of teeth in a dentition is essential for proper speech, mastication, and aesthetics. Teeth are ectodermal organs that develop from the interaction of a thickened epithelium (dental placode) with the neural-crest-derived ectomesenchyme. There is extensive histological, molecular, and genetic evidence regarding how the tooth number is regulated in this serial process, but there is currently no universal classification for tooth number abnormalities. In this review, we propose a novel regulatory network for the tooth number based on the inherent dentition formation process. This network includes three intuitive directions: the development of a single tooth, the formation of a single dentition with elongation of the continual lamina, and tooth replacement with the development of the successional lamina. This article summarizes recent reports on early tooth development and provides an analytical framework to classify future relevant experiments.

A single-component yet multifunctional tongue-mimicking sensor array for upconversion fluorescence biosensing.

In this work, we prepared a type of multiplexing upconversion nanoparticle (UCNP). There are three fluorescence emission peaks when our UCNPs are excited with 980 and 808 nm lasers. These fluorescence peaks of UCNPs can be quenched ("turn off") to varying degrees via fluorescence resonance energy transfer (FRET) when the UCNPs are coated with a polydopamine (PDA) layer, which is a universal quencher self-polymerized from dopamine (DA). Here, we create a novel single-component nanoprobe that can be used for the pattern recognition of antioxidants in a "turn on" manner by integrating with the prevention of PDA formation with an antioxidant. Our sensing strategy is based on the recovery of the fluorescence intensity of three emission peaks to different degrees due to different antioxidants with differential inhibition of PDA formation. Then, these three fluorescence emission peaks of UCNPs are innovatively selected as the sensor array, which enables us to discriminate multiple antioxidants and their mixtures. Simultaneously, the sensor array shows excellent performance in the chiral discrimination of cysteine enantiomers. This is a novel, innovative sensor array that requires only a single component to achieve the upconversion fluorescence pattern and recognize chiral molecules, and it elucidates a more innovative concept towards widespread applications.

Enzymatic Continuous Flow Synthesis of Thiol-Terminated Poly(δ-Valerolactone) and Block Copolymers.

Thiol-terminated poly(δ-valerolactone) is directly synthesized via enzymatic 6-mercapto-1-hexanol initiated ring-opening polymerization in both batch and microreactor. By using Candida antartica Lipase B immobilized tubular reactor, narrowly dispersed poly(δ-valerolactone) with higher thiol fidelity is more efficiently prepared in contrast to the batch reactor. Moreover, the integrated enzyme packed tubular reactor system is established to perform the chain extension experiments. Thiol-terminated poly(δ-valerolactone)-block-poly(ε-caprolactone) and poly(ε-caprolactone)-block-poly(δ-valerolactone) are easily prepared by modulating the monomer introduction sequence.

[The swelling behavior of choline fenofibrate hydrogel matrix tablets using dynamic image analysis].

The purpose of this study is to investigate the effects of formulation on the swelling behavior of choline fenofibrate hydrogel matrix tablets and reveal the relation between swelling property and release profile using dynamic image analysis. The volume swelling ratio (SR) and height/width (k) could evaluate the swelling behavior of matrix tablets well. The mount of hydroxypropyl methylcellulose (HPMC) and the ratio between K15M and K4M affected the volume swelling ratio, while PVP didn't. The three factors all impacted k, which was an indicator of the strength of the gel formed by HPMC. The accumulative release ratio and SR, the rate of swelling and the rate of release were compared. The proper model equations were established for the results with an excellent correlation. The results prove that there is a strong relevance between the swelling behavior and release property. This study provides a guideline in the study design for hydrogel matrix tablets.

[Preparation and properties of thermosensitive in situ gel for ophthalmic formulation containing pearl hydrolyzate].

The study was designed to generate an ophthalmic thermosensitive in situ gel with improved mechanical and mucoadhesive properties that may prolong the retention time to enhance the bioavalability of pearl hydrolyzate. The gene was comprised of poloxamer 407, poloxamer188 and Carbopol 934, which were optimized by central composite design and response surface methodology. The rheological properties, transcorneal permeability, retention time and in vitro release behaviors of the optimal gel formulation were investigated. The gel was Newtonian liquid at 25 ℃ and performed as a semisolid gel with non-Newtonian liquid property with a gelation time of 13 s at 35 ℃. Compared with a conventional eye drops, the ophthalmic in situ gel exhibited a sevenfold increase in retention with a sustained release behavior, which was observed with suitable permeability coefficient at 5.58 cm·s-1. In conclusion, the new gel of pearl hydrolyzate prolonged the release duration of drug, which may decrease the frequency of administration of pearl hydrolyzate.

SERS-encoded nanogapped plasmonic nanoparticles: growth of metallic nanoshell by templating redox-active polymer brushes.

We report a new strategy to synthesize core-shell metal nanoparticles with an interior, Raman tag-encoded nanogap by taking advantage of nanoparticle-templated self-assembly of amphiphilic block copolymers and localized metal precursor reduction by redox-active polymer brushes. Of particular interest for surface-enhanced Raman scattering (SERS) is that the nanogap size can be tailored flexibly, with the sub-2 nm nanogap leading to the highest SERS enhancement. Our results have further demonstrated that surface functionalization of the nanogapped Au nanoparticles with aptamer targeting ligands allows for specific recognition and ultrasensitive detection of cancer cells. The general applicability of this new synthetic strategy, coupled with recent advances in controlled wet-chemical synthesis of functional nanocrystals, opens new avenues to multifunctional core-shell nanoparticles with integrated optical, electronic, and magnetic properties.

Rational development of functional hydrophilic polymer to characterize site-specific glycan differences between bovine milk and colostrum.

As vastly modified on secreted proteins, N-glycosylation is found on milk proteins and undergo dynamic changes during lactation, characterizing milk protein glycosylation would benefit the elucidation of glycosylation pattern differences between samples. However, their low abundance required specific enrichment. Herein, through rational design and controllable synthesis, we developed a novel multi-functional polymer for the isolation of protein glycosylation. It efficiently separated glycopeptides from complex background inferences with mutual efforts of hydrophilic interaction chromatography (HILIC), metal ion affinity and ion exchange. By fine-tuning Ca2+ as regulators of aldehyde hyaluronic acid (HA) conformation, the grafting density of HA was remarkably improved. Moreover, grafting Ti4+ further enhanced the enrichment performance. Application of this material to characterize bovine milk and colostrum proteins yields 479 and 611 intact glycopeptides, respectively. Comparative analysis unraveled the distinct glycosylation pattern as well the different distribution of glycoprotein abundances between the two samples, offering insights for functional food development.

Secondary organic aerosol formation from atmospheric reactions of anisole and associated health effects.

Anisole (methoxybenzene) represents an important marker compound of lignin pyrolysis and a starting material for many chemical products. In this study, secondary organic aerosols (SOA) formed by anisole via various atmospheric processes, including homogeneous photooxidation with varying levels of OH• and NOx and subsequent heterogeneous NO3• dark reactions, were investigated. The yields of anisole SOA, particle-bound organoperoxides, particle-induced oxidative potential (OP), and cytotoxicity were characterized in view of the atmospheric fate of the anisole precursor. Anisole SOA yields ranged between 0.12 and 0.35, depending on the reaction pathways and aging degrees. Chemical analysis of the SOA suggests that cleavage of the benzene ring is the main reaction channel in the photooxidation of anisole to produce low-volatility, highly oxygenated small molecules. Fresh anisole SOA from OH• photooxidation are more light-absorbing and have higher OP and organoperoxide content. The high correlation between SOA OP and organoperoxide content decreases exponentially with the degree of OH• aging. However, the contribution of organoperoxides to OP is minor (<4%), suggesting that other, non-peroxide oxidizers play a central role in anisole SOA OP. The particle-induced OP and particulate organoperoxides yield both reach a maximum value after ∼2 days' of photooxidation, implicating the potential long impact of anisole during atmospheric transport. NOx-involved photooxidation and nighttime NO3• reactions facilitate organic nitrate formation and enhance particle light absorption. High NOx levels suppress anisole SOA formation and organoperoxides yield in photooxidation, with decreased aerosol OP and cellular oxidative stress. In contrast, nighttime aging significantly increases the SOA toxicity and reactive oxygen species (ROS) generation in lung cells. These dynamic properties and the toxicity of anisole SOA advocate consideration of the complicated and consecutive aging processes in depicting the fate of VOCs and assessing the related effects in the atmosphere.

Ionic Hydrogels Based Wearable Sensors to Monitor the Solar Radiation Dose for Vitamin D Production and Sunburn Prevention.

Wearable solar radiation sensors based on ionic hydrogels are facilely prepared to simultaneously monitor the radiation dose for the production of vitamin D and the prevention of sunburn. Tetramethylethylenediamine (TEMED) is neutralized with acrylic acid (AA) to obtain tetramethylethylenediamine acrylate (TEMEDA), which is further polymerized with acrylamide by a free radical reaction. By simply adding MB or NR during the polymerization, the final obtained ionic hydrogels can indicate solar radiation. Due to the extent of discoloration, the discoloration speed of MB and NR is correlated to the radiation dose. This wearable sensor can indicate the solar radiation dose required by the human body to synthesize vitamin D through the discoloration of the ionized hydrogel of MB, whereas those with NR are able to illustrate the threshold of radiation dose that causes potential skin hurt. Therefore, the benefit and drawback of solar radiation can be well balanced by optimizing the exposure time to solar irradiation. In addition, polyurethane cross-linked with a thermoresponsive coating is used as band for this wearable sensor. Due to the hydrophilicity below its transition temperature, the cross-linked band possesses the easy cleaning capability of stains after the daily wear. Such type of wearable sensor can be broadly used for monitoring the solar radiation, especially in outdoor activities.

A combination of membrane relaxation and shear stress significantly improve the flux of gravity-driven membrane system.

Gravity-driven membrane (GDM) filtration system is a promising process for decentralized drinking water treatment. During the operation, membrane relaxation and shear stress could be simply achieved by intermittent filtration and water disturbance (created by occasionally shaking membrane model or stirring water in membrane tank), respectively. To better understand the impact of membrane relaxation and shear stress on the biofouling layer and stable flux in GDM system, action of daily 60-min intermission, daily flushing (cross-flow velocity = 10 cm s-1, 1 min), and the combination of the two (flushed right after the 60-min intermission) were compared. The results showed that membrane relaxation and shear stress lonely was ineffective in improving the stable flux, while their combination enhanced the stable flux by 70%. A more open and spatially heterogeneous biofouling layer with a low extracellular polymeric substance (EPS) content and a high microbial activity was formed under the combination of membrane relaxation and shear stress. In-situ optical coherence tomography (OCT) observation revealed that, during intermission, the absence of pushing force by water flow induced a reversible expansion of biofouling layer, and the biofouling layer restored to its initial state soon after resuming filtration. Shear stress caused abrasion and erosion on the biofouling surface, but it exerted little effect on the interior of biofouling layer. Under the combination, however, both the surface and interior of biofouling layer were disturbed because of 1) the water vortexes caused by rough biofouling layer surface, and 2) the porous structure after 60-min intermission. This disturbance, in turn, helped the biofouling layer maintain its roughness and porosity, thereby improving the stable flux of GDM system.

A Novel Method to Increase Tumor Ablation Zones With RFA by Injecting the Cationic Polymer Solution to Tissues: In Vivo and Computational Studies.

OBJECTIVE: This study aims to examine, for the first time, the introduction of cationic polymer solutions to improve radiofrequency ablation (RFA) in terms of a potentially enlarged ablation zone. METHODS: By using in vivo and computational RFA studies, two cationic polymers, Chitooligosaccharides (COS) and carboxymethyl chitosan (CMC), diluted in deionized water, were injected into tissues separately surrounding the RF bipolar electrode prior to power application. A total of 9 rabbits were used to 1) measure the increase in electrical conductivity of tissues injected with the cationic polymer solutions, and 2) explore the enhancement of the ablation performance in RFA trials. A computer model of RFA comprising a model of the solution diffusion with an RF thermal ablation model was also built, validated by the in vivo experiment, to quantitatively study the effect of cationic polymer solutions on ablation performances. RESULTS: Compared to the control group, the electrical conductivity of rabbit liver tissues was increased by 42.20% (0.282 ± 0.006 vs. 0.401 ± 0.048 S/m, P = 0.001) and 43.97% (0.282 ± 0.006 vs. 0.406 ± 0.042 S/m, P = 0.001) by injecting the COS and CMC solution at the concentration of 100 mg/mL into the tissues, denoted COSDW100 and CMCDW100, respectively. Consequently, the in vivo experiments show that the ablation zone was enlarged by 95% (47.6 ± 6.3 vs. 92.6 ± 11.5 mm2, P < 0.001) and 87% (47.6± 6.3 vs. 88.8 ± 9.6 mm2, P < 0.001) by COSDW100 and CMCDW100, respectively. The computer simulation shows that the ablation zone was enlarged by 71% (51.9 vs. 88.7 mm2) and 63% (51.9 vs. 84.7 mm2) by COSDW100 and CMCDW100, respectively. CONCLUSION: The injection of the cationic solution can greatly improve the performance of RFA treatment in terms of enlarging the ablation zone, which is due to the increase in the electrical conductivity of liver tissues surrounding the RF electrode. SIGNIFICANCE: This study contributes to the improvement of RFA in the treatment of large tumors.

Polydopamine-mediated synthesis of core-shell gold@calcium phosphate nanoparticles for enzyme immobilization.

Considerable efforts have been made to develop reliable immobilization approaches to improve enzyme stability and reusability. However, relatively complicated preparation often leads to compromised enzyme activity. This study reports a facile method of retaining full enzymatic activity by immobilizing glucose oxidase (GOx) into core-shell nanoparticles with polydopamine (PDA) sandwiched between a gold nanoparticle (Au NP) core and a calcium phosphate (CaP) shell (Au@PDA@CaP). The strong adhesion of PDA on Au NPs and its metal chelating properties directed the preferential growth of the CaP shell on the Au NPs, leading to well-dispersed and uniform nanohybrids. Concurrent loading of GOx during the growth of CaP held the key to the successful immobilization of GOx. As a result, Au@PDA@CaP-immobilized GOx had similar activity but better resistance against heating, long-term storage and repeated uses compared to free GOx. This work provides a green strategy for constructing nanobiocatalysts with high enzyme activity and stability.

Effects of water temperature and light intensity on the performance of gravity-driven membrane system.

The selection of favorable environmental conditions for gravity-driven membrane (GDM) systems is crucial to their widespread application. In this study, GDM systems operated under different light intensities (illuminance levels of 0, 200, and 3000 Lux) and water temperatures (10, 20, and 30 °C) were investigated for their performance and fouling layer characteristics. The results showed that indoor light (200 Lux) had limited effects on the performance of the GDM system. However, full daylight (3000 Lux) led to algal growth; these algae increased fouling resistance and deteriorated permeate water by releasing algogenic organic matter, although they could also enhance the heterogeneity of the biofouling layer by increasing the microbial activity. Water temperature rarely influenced the total organic matter removal. The fouling layers had different thicknesses and heterogeneity, but the same level of EPS; therefore, the hydraulic resistances of these fouling layer were almost the same at different water temperatures. These findings suggest that GDM system could be operated at low water temperature and indoor light conditions, and that strong light should be avoided during the operation of GDM systems.

Coordination polymers of Tb3+/Nucleotide as smart chemical nose/tongue toward pattern-recognition-based and time-resolved fluorescence sensing.

The abundant functional groups on guanosine monophosphate (GMP) make it possible to interact with various metal ions. The subtle difference in the structure of GMP and deoxy-guanosine monophosphate (dGMP) coupled with Tb3+ can be readily exploited to form two coordination polymers, which have been unveiled as two time-resolved fluorescence (TRF) sensing reporters (Tb-GMP and Tb-dGMP) in our study. Based on this finding, herein, we have proposed a novel TRF orthogonal sensing array (Tb-GMP/dGMP) for pattern-recognition-based sensing of various metal ions. In addition, upon integration of some thiol-affinity metal ions, Tb-GMP/dGMP can be further extended to construct two metal ion-involved pattern-recognition-based sensor arrays (Tb-GMP/dGMP-Cu, Tb-GMP/dGMP-Ag) for the TRF sensing different levels of disease-relevant biothiols in biofluids, illustrating the powerful and multifunctional capabilities of the Tb-GMP/dGMP system and would inspire simpler and more widespread designs of chemical nose/tongue-based applications.

Development of High-Performance Biodegradable Rigid Polyurethane Foams Using Full Modified Soy-Based Polyols.

Fossil fuel resources depletion and growing concern about environmental issues have raised the demand for newly sustainable biomaterials. To address this challenge, a new type of biodegradable and environmental rigid polyurethane foam called rigid polyurethane foams (RPUF)-M from full modified soy-based polyols have been synthesized without the addition of petroleum-based polyols. On the basis of the analysis of structure-activity relationship, a new kind of biobased polyurethane polyols called Bio-polyol-M was designed and synthesized directly from epoxidized soybean oil and a novel polyhydroxy compound in a three-step continuous microflow system. In the continuous microflow system, the epoxidation of soybean oil, the synthesis of GLPO (glycerine with styrene oxide), and the ring-opening reaction of epoxidized soybean oil were coupled. Another soy-polyol called Bio-polyol-B was synthesized in batch mode. In comparison to those of Bio-polyol-B, Bio-polyol-M had a higher hydroxyl number and a much lower viscosity. The RPUF-M also possessed a series of advantages over the rigid polyurethane foam called RPUF-B from Bio-polyol-B.

A highly selective potentiometric sensor of molybdate based on a mu-oxo-bridged manganeseporphyrin dimer.

A novel high-selective potentiometric sensor for molybdate was prepared with a PVC membrane combining mu-oxo-bis[5,10,15,20-tetra(p-methylphenyl)porphinatomanganese(III)] [[Mn(p-Me)TPP](2)O] as an electroactive material and 2-nitrophenyl octyl ether (o-NPOE) as a plasticizer in the percentage ratio of 3:65:32, [Mn(p-Me)TPP](2)O:o-NPOE:PVC (w:w). The sensor exhibited a linear response with a Nernstian slope of 30.5 mV per decade within a concentration range of 2.1 x 10(-6) to 1.0 x 10(-1) M MoO4(2-), with a working pH range from 5.0 to 12.5, and a fast response time of less than 15 s. The electrode showed improved selectivity toward molybdate with respect to common coexisting anions compared to monometalloporphyrin counterparts. Several electroactive materials and solvent mediators were compared and the experimental conditions were optimized. The sensor is preliminary applied to the assay of MoO4(2-) in corrosion inhibitor samples with satisfactory results.

Cationic polycarbonate-grafted superparamagnetic nanoparticles with synergistic dual-modality antimicrobial activity.

We report a new class of antimicrobial nanomaterials with biodegradable cationic polycarbonates grafted on superparamagnetic nanoparticles. Our results have shown that end-functionalized cationic polycarbonates, synthesized by organocatalytic ring opening polymerization, can be grafted onto superparamagnetic MnFe2O4 nanoparticles via ligand exchange. In comparison with the individual building blocks, the core-shell hybrid nanoparticles led to improved antimicrobial activities in two ways: first, the cationic polycarbonates in a brush form afforded a greater charge density than that of free polymer chains, resulting in stronger interactions with bacterial surfaces. Second, the structural integration of the "soft" polycarbonate shell and the "hard" superparamagnetic core in the hybrid nanoparticles brings about a synergistic action of membrane disruption by the cationic shell and magnetic hyperthermia by the nanoparticle core. The combination of two physical killing mechanisms holds great promise in fighting against a broad spectrum of bacterial pathogens.

Versatile Core-Shell Nanoparticle@Metal-Organic Framework Nanohybrids: Exploiting Mussel-Inspired Polydopamine for Tailored Structural Integration.

We report a versatile strategy based on the use of multifunctional mussel-inspired polydopamine for constructing well-defined single-nanoparticle@metal-organic framework (MOF) core-shell nanohybrids. The capability of polydopamine to form a robust conformal coating on colloidal substrates of any composition and to direct the heterogeneous nucleation and growth of MOFs makes it possible for customized structural integration of a broad range of inorganic/organic nanoparticles and functional MOFs. Furthermore, the unique redox activity of polydopamine adds additional possibilities to tailor the functionalities of the nanohybrids by sandwiching plasmonic/catalytic metal nanostructures between the core and shell via localized reduction. The core-shell nanohybrids, with the molecular sieving effect of the MOF shell complementing the intrinsic properties of nanoparticle cores, represent a unique class of nanomaterials of considerable current interest for catalysis, sensing, and nanomedicine.

Surface enhanced Raman scattering by graphene-nanosheet-gapped plasmonic nanoparticle arrays for multiplexed DNA detection.

We have developed a new type of surface enhanced Raman scattering (SERS) substrate with thiolated graphene oxide (tGO) nanosheets sandwiched between two layers of closely packed plasmonic nanoparticles. The trilayered substrate is built up through alternative loading of interfacially assembled plasmonic nanoparticle arrays and tGO nanosheets, followed by coating the nanoparticle surfaces with poly(ethylene glycol) (PEG). Here tGO plays multifunctional roles as a 2D scaffold to immobilized interfacially assembled plasmonic nanoparticles, a nanospacer to create SERS-active nanogaps between two layers of nanoparticle arrays, and a molecule harvester to enrich molecules of interest viaπ-π interaction. In particular, the molecule harvesting capability of the tGO nanospacer and the stealth properties of PEG coating on the plasmonic nanoparticles collectively lead to preferential positioning of selective targets such as aromatic molecules and single-stranded DNA at the SERS-active nanogap hotspots. We have demonstrated that an SERS assay based on the PEGylated trilayered substrate, in combination with magnetic separation, allows for sensitive, multiplexed "signal-off" detection of DNA sequences of bacterial pathogens.

Interfacial assembly of mussel-inspired au@ag@ polydopamine core-shell nanoparticles for recyclable nanocatalysts.

Recyclable nanocatalysts of core-shell bimetallic nanocrystals are developed through polydopamine coating-directed one-step seeded growth, interfacial assembly, and substrate-immobilization of Au@Ag core-shell nanocrystals. This strategy provides new opportunities to design and optimize heterogeneous nanocatalysts with tailored size, morphology, chemical configuration, and supporting substrates for metal-catalyzed reactions.