Nanochemistry of gold: from surface engineering to dental healthcare applications.

Advancements in nanochemistry have led to the development of engineered gold nanostructures (GNSs) with remarkable potential for a variety of dental healthcare applications. These innovative nanomaterials offer unique properties and functionalities that can significantly improve dental diagnostics, treatment, and overall oral healthcare applications. This review provides an overview of the latest advancements in the design, synthesis, and application of GNSs for dental healthcare applications. Engineered GNSs have emerged as versatile tools, demonstrating immense potential across different aspects of dentistry, including enhanced imaging and diagnosis, prevention, bioactive coatings, and targeted treatment of oral diseases. Key highlights encompass the precise control over GNSs' size, crystal structure, shape, and surface functionalization, enabling their integration into sensing, imaging diagnostics, drug delivery systems, and regenerative therapies. GNSs, with their exceptional biocompatibility and antimicrobial properties, have demonstrated efficacy in combating dental caries, periodontitis, peri-implantitis, and oral mucosal diseases. Additionally, they show great promise in the development of advanced sensing techniques for early diagnosis, such as nanobiosensor technology, while their role in targeted drug delivery, photothermal therapy, and immunomodulatory approaches has opened new avenues for oral cancer therapy. Challenges including long-term toxicity, biosafety, immune recognition, and personalized treatment are under rigorous investigation. As research at the intersection of nanotechnology and dentistry continues to thrive, this review highlights the transformative potential of engineered GNSs in revolutionizing dental healthcare, offering accurate, personalized, and minimally invasive solutions to address the oral health challenges of the modern era.

Enhancing Substrate Channeling with Multi-Enzyme Architectures in Hydrogen-Bonded Organic Frameworks.

Hydrogen-bonded organic frameworks (HOF) represent an emerging category of organic structures with high crystallinity and metal-free, which are not commonly observed in alternative porous organic frameworks. These needle-like porous structure can help in stabilizing enzymes and allow transfer of molecules between enzymes participating in cascade reactions for enhanced substrate channelling. Herein, we systematically synthesized and investigated the stability of HOF at extreme conditions followed by one-pot encapsulation of single and bi-enzyme systems. Firstly, we observed HOF to be stable at pH 1 to 14 and at high temperatures (up to 115 °C). Secondly, the encapsulated glucose oxidase enzyme (GOX) showed 80 % and 90 % of its original activity at 70 °C and pH 11, respectively. Thirdly, transient time close to 0 seconds was observed for HOF encapsulated bi-enzyme cascade reaction system demonstrating a 4.25-fold improvement in catalytic activity when compared to free enzymes with enhanced substrate channelling. Our findings showcase a facile system synthesized under ambient conditions to encapsulate and stabilize enzymes at extreme conditions.

An electrochemical biosensor for T4 polynucleotide kinase activity assay based on host-guest recognition between phosphate pillar[5]arene@MWCNTs and thionine.

T4 polynucleotide kinase helps with DNA recombination and repair. In this study, an electrochemical biosensor was developed for a T4 polynucleotide kinase activity assay and inhibitor screening based on phosphate pillar[5]arene and multi-walled carbon nanotube nanocomposites. The water-soluble pillar[5]arene was employed as the host to complex thionine guest molecules. The substrate DNA with a 5'-hydroxyl group initially self-assembled on the gold electrode surface through chemical adsorption of the thiol group, which was phosphorylated in the presence of T4 polynucleotide kinase. Titanium dioxide nanoparticles served as a bridge to link phosphorylated DNA and phosphate pillar[5]arene and multi-walled carbon nanotube composite due to strong phosphate-Ti4+-phosphate chemistry. Through supramolecular host-guest recognition, thionine molecules were able to penetrate the pillar[5]arene cavity, resulting in an enhanced electrochemical response signal. The electrochemical signal is proportional to the T4 polynucleotide kinase concentration in the range of 10-5 to 15 U mL-1 with a detection limit of 5 × 10-6 U mL-1. It was also effective in measuring HeLa cell lysate-related T4 polynucleotide kinase activity and inhibitor screening. The proposed method offers a unique sensing platform for kinase activity measurement, holding great potential in nucleotide kinase-target drug development, clinical diagnostics, and inhibitor screening.

A self-powered electrochemical aptasensor for the detection of 17ß-estradiol based on carbon nanocages/gold nanoparticles and DNA bioconjugate mediated biofuel cells.

17ß-Estradiol (E2) is an important endogenous estrogen, which disturbs the endocrine system and poses a threat to human health because of its accumulation in the human body. Herein, a biofuel cell (BFC)-based self-powered electrochemical aptasensor was developed for E2 detection. Porous carbon nanocage/gold nanoparticle composite modified indium tin oxide (CNC/AuNP/ITO) and glucose oxidase modified CNC/AuNP/ITO were used as the biocathode and bioanode of BFCs, respectively. [Fe(CN)6]3- was selected as an electroactive probe, which was entrapped in the pores of positively charged magnetic Fe3O4 nanoparticles (PMNPs) and then capped with a negatively charged E2 aptamer to form a DNA bioconjugate. The presence of the target E2 triggered the entrapped [Fe(CN)6]3- probe release due to the removal of the aptamer via specific recognition, which resulted in the transfer of electrons produced by glucose oxidation at the bioanode to the biocathode and produced a high open-circuit voltage (EOCV). Consequently, a "signal-on" homogeneous self-powered aptasensor for E2 assay was realized. Promisingly, the BFC-based self-powered aptasensor has particularly high sensitivity for E2 detection in the concentration range of 0.5 pg mL-1 to 15 ng mL-1 with a detection limit of 0.16 pg mL-1 (S/N = 3). Therefore, the proposed BFC-based self-powered electrochemical aptasensor has great promise to be applied as a successful prototype of a portable and on-site bioassay in the field of environment monitoring and food safety.

Inversion of magnetic diameter distribution of magnetic fluids under high and low temperatures.

The magnetic diameter is a crucial factor affecting the magnetic properties of magnetic fluids. The magnetic diameter distribution can be estimated based on the magnetic properties. However, the magnetic dipole interaction of magnetic nanoparticles (MNPs) and the variation of the magnetic diameter with temperature have received relatively little attention in previous research. Hence, this research proposes the AP-MMF1-L method to inverse the magnetic diameter which considers the magnetic dipole interaction and derives the magnetic diameter at different temperatures. Firstly, the AP-MMF1-L uses the least square method between the first-order modified mean-field Langevin function (MMF1-L) and the measured magnetization curve as the objective function. Meanwhile, the hybrid Artificial bee colony-particle swarm (AP) optimization algorithm is introduced to inverse the optimal magnetic diameter distribution. Secondly, the hydrodynamic diameter distribution experimental values are compared with the theoretical values, demonstrating the AP-MMF1-L method obtains accurate inversion results of the magnetic diameter distribution when compared to other models. Finally, the arithmetic mean of the magnetic diameter at different temperatures is investigated, revealing a decreasing trend as the temperature rises, approximately following a linear distribution. The AP-MMF1-L provides a novel and effective tool for accurately determining the magnetic diameter of the MNPs across various temperatures.

Nanoarchitectonics-based electrochemical aptasensors for highly efficient exosome detection.

Exosomes, a type of extracellular vesicles, have attracted considerable attention due to their ability to provide valuable insights into the pathophysiological microenvironment of the cells from which they originate. This characteristic implicates their potential use as diagnostic disease biomarkers clinically, including cancer, infectious diseases, neurodegenerative disorders, and cardiovascular diseases. Aptasensors, which are electrochemical aptamers based biosensing devices, have emerged as a new class of powerful detection technology to conventional methods like ELISA and Western analysis, primarily because of their capability for high-performance bioanalysis. This review covers the current research landscape on the detection of exosomes utilizing nanoarchitectonics strategy for the development of electrochemical aptasensors. Strategies involving signal amplification and biofouling prevention are discussed, with an emphasis on nanoarchitectonics-based bio-interfaces, showcasing their potential to enhance sensitivity and selectivity through optimal conduction and mass transport properties. The ongoing challenges to broaden the clinical applications of these biosensors are also highlighted.

This review emphasizes the significant impact of integrating nanoarchitectonics into aptamer-based electrochemical biosensors for exosome detection, thereby enhancing early disease detection and monitoring disease progression in clinical settings.

Application of Independent Component Analysis and Nelder-Mead Particle Swarm Optimization Algorithm in Non-Contact Blood Pressure Estimation.

In recent years, hypertension has become one of the leading causes of illness and death worldwide. Changes in lifestyle among the population have led to an increasing prevalence of hypertension. This study proposes a non-contact blood pressure estimation method that allows patients to conveniently monitor their blood pressure values. By utilizing a webcam to track facial features and the region of interest (ROI) for obtaining forehead images, independent component analysis (ICA) is employed to eliminate artifact signals. Subsequently, physiological parameters are calculated using the principle of optical wave reflection. The Nelder-Mead (NM) simplex method is combined with the particle swarm optimization (PSO) algorithm to optimize the empirical parameters, thus enhancing computational efficiency and accurately determining the optimal solution for blood pressure estimation. The influences of light intensity and camera distance on the experimental results are also discussed. Furthermore, the measurement time is only 10 s. The superior accuracy and efficiency of the proposed methodology are demonstrated by comparing them with those in other published literature.

Highly Selective N2 Electroreduction to NH3 Using a Boron-Vacancy-Rich Diatomic NbB Catalyst.

The ambient electrochemical N2 reduction reaction (NRR) is a future approach for the artificial NH3 synthesis to overcome the problems of high-energy consumption and environmental pollution by Haber-Bosch technology. However, the challenge of N2 activation on a catalyst surface and the competitive hydrogen evolution reaction make the current NRR unsatisfied. Herein, this work demonstrates that NbB2 nanoflakes (NFs) exhibit excellent selectivity and durability in NRR, which produces NH3 with a production rate of 30.5 µg h-1 mgcat -1 and a super-high Faraday efficiency (FE) of 40.2%. The high-selective NH3 production is attributed to the large amount of active B vacancies on the surface of NbB2 NFs. Density functional theory calculations suggest that the multiple atomic adsorption of N2 on both unsaturated Nb and B atoms results in a significantly stretched N2 molecule. The weakened NN triple bonds are easier to be broken for a biased NH3 production. The diatomic catalysis is a future approach for NRR as it shows a special N2 adsorption mode that can be well engineered.

Boosting Plant Photosynthesis with Carbon Dots: A Critical Review of Performance and Prospects.

Artificially augmented photosynthesis in nano-bionic plants requires tunable nano-antenna structures with physiochemical and optoelectronic properties, as well as unique light conversion capabilities. The use of nanomaterials to promote light capture across photosystems, primarily by carbon dots, has shown promising results in enhancing photosynthesis through tunable uptake, translocation, and biocompatibility. Carbon dots possess the ability to perform both down and up-light conversions, making them effective light promoters for harnessing solar energy beyond visible light wavelengths.This review presents and discusses the recent progress in fabrication, chemistry, and morphology, as well as other properties such as photoluminescence and energy conversion efficiency of nano-antennas based on carbon dots. The performance of artificially boosted photosynthesis is discussed and then correlated with the conversion properties of carbon dots and how they are applied to plant models. The challenges related to the nanomaterial delivery and the performance evaluation practices in modified photosystems, consideration of the reliability of this approach, and the potential avenues for performance improvements through other types of nano-antennas based on alternative nanomaterials are also critically evaluated. It is anticipated that this review will stimulate more high-quality research in plant nano-bionics and provide avenues to enhance photosynthesis for future agricultural applications.

Graphene as a nano-delivery vehicle in agriculture - current knowledge and future prospects.

Graphene has triggered enormous interest in, and exploration of, its applications in diverse areas of science and technology due to its unique properties. While graphene has displayed great potential as a nano-delivery system for drugs and biomolecules in biomedicine, its application as a nanocarrier in agriculture has only begun to be explored. Conventional fertilizers and agricultural delivery systems have a number of disadvantages, such as: fast release of the active ingredient, low delivery efficiency, rapid degradation and low stability that often leads to their over-application and consequent environmental problems. Advanced nano fertilizers with high carrier efficiency and slow and controlled release are now considered the gold standard for promoting agricultural sustainability while protecting the environment. Graphene's attractive properties include large surface area, chemical stability, mechanical stability, tunable surface chemistry and low toxicity making it a promising material on which to base agricultural delivery systems. Recent research has demonstrated considerable success in the use of graphene for agricultural applications, including its utilization as a delivery vehicle for plant nutrients and crop protection agents, as well as in post-harvest management of crops. This review, therefore, presents a comprehensive overview of the current status of graphene-based nanocarriers in agriculture. Additionally, the review outlines the surface functionalization methods used for effective molecular delivery, various strategies for nano-vehicle design and the underlying features necessary for a graphene-based agro-delivery system. Finally, the review discusses directions for further research in optimization of graphene-based nanocarriers.

In Situ Immobilization of Multi-Enzymes for Enhanced Substrate Channeling of Enzyme Cascade Reactions: A Nanoarchitectonics Approach by Directed Metal-Organic Frameworks.

Rationally tailoring a controlled spatial organization of enzymes in a nanoarchitecture for multi-enzyme cascade reactions can enhance the catalytic efficiency via substrate channeling. However, attaining substrate channeling is a grand challenge, requiring sophisticated techniques. Herein, we report facile polymer-directed metal-organic framework (MOF)-based nanoarchitechtonics for realizing a desirable enzyme architecture with significantly enhanced substrate channeling. The new method involves the use of poly(acrylamide-co-diallyldimethylammonium chloride) (PADD) as a modulator in a one-step process for simultaneous MOF synthesis and co-immobilization of enzymes (GOx and HRP). The resultant enzymes-PADD@MOFs constructs showed a closely packed nanoarchitecture with enhanced substrate channeling. A transient time close to 0 s was observed, owing to a short diffusion path for substrates in a 2D spindle-shaped structure and their direct transfer from one enzyme to another. This enzyme cascade reaction system showed a 3.5-fold increase in catalytic activity in comparison to free enzymes. The findings provide a new insight into using polymer-directed MOF-based enzyme nanoarchitectures to improve catalytic efficiency and selectivity.

Zero-Carbon Emission Chemical Method to Remove Formaldehyde without Catalyst by Highly Porous Polymer Composites at Room Temperature.

Herein, the fabrication of reduced graphene oxide (RGO)-templated polymer composites for chemical removal of gaseous formaldehyde under ambient conditions is presented. The chemical removal of formaldehyde is achieved by a nucleophilic addition reaction between formaldehyde and aminooxy groups on the polymer chain ends to form the oxime bonds with the only byproduct of H2 O. RGO is essential since it not only has an ultralarge surface area but also can act as a perfect template for immobilizing pyrene-terminated and aminooxy-functionalized polymers via strong π-π stacking interactions, while melamine foam provides a three-dimensional skeleton for loading RGO/polymer composites to afford a porous 3D structure for efficient formaldehyde removal. Since the oxime bond can be cleaved into aminooxy group in acidic media, the RGO/polymer composite can be regenerated for repeatable usage, which shows an excellent performance of adsorbing 14 mg of formaldehyde by 100 mg of the polymer at ambient condition.

A novel colorimetric/fluorescent dual-signal probe based on silver nanoparticles functionalized with L-cysteine and rhodamine 6G derivatives for copper ion detection and cell imaging.

The dual-signal probe utilizing functionalized silver nanoparticles (AgNPs) is a promising sensing tool. Herein, a novel colorimetric/fluorescent dual-signal probe (AgNPs-L-Cys-Rh6G2) was fabricated for copper ion (Cu2+) detection and cell imaging by using L-cysteine as a "bridge" to connect AgNPs and rhodamine 6G derivatives. The AgNPs-L-Cys-Rh6G2 probe exhibits a dual-signal response to Cu2+ due to Rh6G2 hydrolysis, resulting in a high fluorescence response and a significant change in color from light yellow to pink under sunlight. The linear detection ranges of the AgNPs-L-Cys-Rh6G2 probe for Cu2+ were 100-450 µM and 150-650 µM using fluorescent and colorimetry methods, respectively. The detection limits were as low as 0.169 µM and 1.36 µM, respectively. Meanwhile, the proposed probe was applied to detect Cu2+ in the actual sediment with satisfactory recovery and low relative standard deviation. Furthermore, the probe was further employed for fluorescence imaging in HeLa cells. In brief, the developed AgNPs-L-Cys-Rh6G2 sensing platform can be used for simultaneous Cu2+ determination and cell imaging.

An electrochemical biosensor for T4 polynucleotide kinase activity identification according to host-guest recognition among phosphate pillar[5]arene@palladium nanoparticles@reduced graphene oxide nanocomposite and toluidine blue.

T4 polynucleotide kinase (T4 PNK) helps with DNA recombination and repair. In this work, a phosphate pillar[5]arene@palladium nanoparticles@reduced graphene oxide nanocomposite (PP5@PdNPs@rGO)-based electrochemical biosensor was created to identify T4 PNK activities. The PP5 used to complex toluidine blue (TB) guest molecules is water-soluble. With T4 PNK and ATP, the substrate DNA, which included a 5'-hydroxyl group, initially self-assembled over the gold electrode surface by chemical adsorption of the thiol units. Strong phosphate-Zr4+-phosphate chemistry allowed Zr4+ to act as a bridge between phosphorylated DNA and PP5@PdNPs@rGO. Through a supramolecular host-guest recognition connection, TB molecules were able to penetrate the PP5 cavity, where they produced a stronger electrochemical response. With a 5 × 10-7 U mL-1 detection limit, the electrochemical signal is linear in the 10-6 to 1 U mL-1 T4 PNK concentration range. It was also effective in measuring HeLa cell lysate-related PNK activities and screening PNK inhibitors. Nucleotide kinase-target drug development, clinical diagnostics, and screening for inhibitors all stand to benefit greatly from the suggested technology, which offers a unique sensing mechanism for kinase activity measurement.

2D Active Nanobots Based on Soft Nanoarchitectonics Powered by an Ultralow Fuel Concentration.

Enzyme catalysis to power micro/nanomotors has received tremendous attention because of the vast potential in applications ranging from biomedicine to environmental remediation. However, the current design is mainly based on a complex three-dimensional (3D) architecture, with limited accessible surface areas for the catalytic sites, and thus requires a higher fuel concentration to achieve active motion. Herein we report for the first time an enzyme-powered 2D nanobot, which was designed by a facile strategy based on soft nanoarchitectonics for active motion at an ultralow fuel concentration (0.003 % H2 O2 ). The 2D nanobots exhibited efficient positive chemotactic behavior and the ability to swim against gravity by virtue of solutal buoyancy. As a proof-of-concept, the 2D nanobots showed an excellent capability for "on-the-fly" removal of methylene blue (MB) dye with an efficiency of 85 %.

Direct Observation of Amide Bond Formation in a Plasmonic Nanocavity Triggered by Single Nanoparticle Collisions.

The real-time observation of chemical bond formation at the single-molecule level is one of the great challenges in the fields of organic and biomolecular chemistry. Valuable information can be gleaned that is not accessible using ensemble-average measurements. Although remarkably sophisticated techniques for monitoring chemical reactions have been developed, the ability to detect the specific formation of a chemical bond in situ at the single-molecule level has remained an elusive goal. Amide bonds are routinely formed from the aminolysis of N-hydroxysuccinimide (NHS) esters by primary amines, and the protocol is widely used for the synthesis, cross-linking, and labeling of peptides and proteins. Herein, a plasmonic nanocavity was applied to study aminolysis reaction for amide bond formation, which was initiated by single nanoparticle collision events between suitably functionalized free-moving gold nanoparticles and a gold nanoelectrode in an aqueous buffer. By means of simultaneous surface enhanced Raman spectroscopy (SERS) and single-entity electrochemistry (EC) measurements, we have probed the dynamic evolution of amide bond formation in the aminolysis reaction with 10 s of millisecond time resolution. Hence, we demonstrate that single-entity EC-SERS is a valuable and sensitive technique by which chemical reactions can be studied at the single-molecule level.

Soft Nanoarchitectonics for Enantioselective Biosensing.

Chirality is a fundamental property of a molecule, and the significant progress in chirality detection and quantification of a molecule has inspired major advances in various fields ranging from chemistry, biology, to biotechnology and pharmacology. Chiral molecules have identical molecular formulas, atom-to-atom linkages, and bonding distances, and as such they are difficult to distinguish both sensitively and selectively. Today, most new drugs and those under development are chiral, which requires technological developments in the separation and detection of chiral molecules. Therefore, rapid and facile methods to detect and discriminate chiral compounds are necessary to accelerate advances in many research fields. The challenges in analysis stem from the obvious fact that chiral molecules have the same physical properties. Although significant progress on the detection of enantiomeric composition has been achieved in the past decade, in order to fully realize the capacity of chiral molecular interrogation, highly sensitive and selective, portable, and easy-to-use detection remains challenging because of the limitation of conventional techniques.Soft nanoarchitectonics is a new concept for the fabrication of functional soft material systems through harmonization of various actions including atomic/molecular-level manipulation, chemical reactions, self-assembly and self-organization, and their modulation by external fields/stimuli. Soft nanoarchitectonics has been widely used as a key enabling technology for integrating predefined molecular functionalities including electrochemical, optical, catalytic, or biological properties into biosensing devices, which provides exciting opportunities to design, assemble, and fabricate tailored nanosystems to enable new sensing strategies for chiral molecules.In this Account, we aim to concisely discuss how these molecule-inspired soft nanoarchitectonics work for enantioselective sensing. We will first outline the basic principle and mechanistic insights of the soft nanoarchitectonics approach for enantioselective sensing, and then we will describe the new breakthroughs and trends in the area that have been most recently reported by our groups and others. There will also be a discussion on the merits of soft nanoarchitectonics based sensing in comparison to conventional analytical methods. Finally, with this Account, we hope to spark new chiral molecule sensing strategies by fundamentally understanding chiral recognition and engineering soft nanoarchitectonics with programmable structures and predictable sensing properties.

In Situ Synthesis of CoCeSx Bimetallic Sulfide Nanoparticles on a Bi-Pyrene Terminated Molecular Wire Modified Graphene Surface for Supercapacitors.

The excellent electrical conductivity of graphene is due to its highly-conjugated structures. Manipulation of the electronic and mechanical properties of graphene can be achieved by controlling the destruction of its in-sheet conjugation system. Herein, we report the preparation of CoCeSx -SA@BPMW@RGO through π-π stacking interactions at the molecular level. In this study, sodium alginate was reacted with Co2+ and Ce3+ , and the composite was loaded onto a graphene surface. The graphene sheets were prepared using a bi-pyrene terminated molecular wire (BPMW) to avoid re-stacking of the grapheme sheets, thereby forming nanoscale spaces between sheets. The angle between the BPMW coplanar pyrene group and the phenyl group was 33.2°, and the graphene layer is supported in an oblique direction. Finally, a three-dimensional porous composite was obtained after annealing and vulcanization. The obtained CoCeSx -SA@BPMW@RGO exhibited excellent electrical conductivity and remarkable cycle stability. When the current density was 1 A g-1 , its specific capacitance was as high as 1004 F g-1 . BPMW modifies graphene through the synergistic effect of π-π stacking interaction and special structure to obtain excellent electrochemical performance. Moreover, a solid-state asymmetric supercapacitor device was fabricated based on the synthesized CoCeSx -SA@BPMW@RGO hybrid, which exhibited a power density of 979 W kg-1 at an energy density of 23.96 Wh kg-1 .

Effect of Triton X-100 on the Activity and Selectivity of Lipase Immobilized on Chemically Reduced Graphene Oxides.

The effect of support hydrophobicity on lipase activity and substrate selectivity was investigated with and without Triton X-100 (TX-100). Lipases from Thermomyces lanuginosa (TL) and Alcaligenes sp. (QLM) were immobilized on graphene oxide (GO) and a range of chemically reduced graphene oxides (CRGOs) with different levels of surface hydrophobicity. Activity assays using 4-hydroxy-N-propyl-1,8-naphthalimide (NAP) esters of varying chain lengths (NAP-butyrate (NAP-B), NAP-octanoate (NAP-O), and NAP-palmitate (NAP-P)) showed that the activity of immobilized QLM and TL decreased by more than 60% on GO and 80% on CRGO (2 h), with activity decreasing further as surface hydrophobicity of the CRGOs increased. Across the hydrophobicity range of GO/CRGOs, the substrate selectivity of QLM shifted from more readily hydrolyzing NAP-P to NAP-B, while TL retained its substrate selectivity for NAP-O. Lipase TL was also shown to desorb from GO and 2 h CRGO when mixed with NAP-O and NAP-P, whereas QLM did not. Circular dichroism analyses of the lipase α-helix content correlate to the observed activity data, with decreases in the α-helical content (40% in TL and 20% in QLM relative to free lipase) consistent with decreases in activity after immobilization on GO. α-Helical content decreased even further as the surface hydrophobicity of CRGOs increased. Attenuated total reflectance-Fourier transform infrared spectroscopy also showed significant changes to the lipase secondary structure upon immobilization. The addition of TX-100 into the activity assay modified the substrate selectivity of immobilized QLM, improving the activity against NAP-O (90%) and NAP-P (67%) compared to the activity measured without TX-100. It was shown that TX-100 primarily affected the activity of QLM by interacting with the ester substrate and the lipase itself. This study provides an improved understanding of how support hydrophobicity and the presence of TX-100 can affect activity/selectivity of lipases immobilized on hydrophobic supports.

Effects of gold nanoparticles combined with human ß-defensin 3 on the alveolar bone loss of periodontitis in rat.

BACKGROUND: Nanomaterials of biomedicine and tissue engineering have been proposed for the treatment of periodontitis in recent years. This study aimed to investigate the effects of gold nanoparticles (AuNPs) combined with human ß-defensin 3 (hBD3) on the repair of the alveolar bones of experimental periodontitis in rats. METHODS: A model of experimental periodontitis was established by ligation of the maxillary second molars with silk thread in rats, which were treated with or without AuNPs combined with hBD3. Micro-computerized tomography (micro-CT) scanning, enzyme-linked immunosorbent assay, and histological and immunohistochemical staining, including alkaline phosphatase (ALP), osteoprotegerin (OPG), tartrate-resistant acid phosphatase (TRAP), and receptor activator of NF-κB ligand (RANKL), were used to analyze the samples. RESULTS: Micro-CT demonstrated that the alveolar bone resorption was significantly reduced after the treatment with AuNPs combined with hBD3. Levels of TNF-α and IL-6 were decreased markedly compared with the ligation group. H&E and Masson staining showed that AuNPs combined with hBD3 group had less inflammatory cell infiltration, collagen fibrosis and fracture, but higher calcification in the new bone tissue. Moreover, the administration of AuNPs combined with hBD3 increased the expression levels of ALP and OPG (related to bone formation) while decreasing the expression levels of TRAP and RANKL (related to bone resorption) expression. CONCLUSIONS: AuNPs combined with hBD3 had a protective effect on the progression of experimental periodontitis in rats and played a certain role in suppressing osteoclastogenesis and alleviating the inflammatory destruction of periodontitis along with the promotion of bone repair.