A bioorthogonal system reveals antitumour immune function of pyroptosis.

Bioorthogonal chemistry capable of operating in live animals is needed to investigate biological processes such as cell death and immunity. Recent studies have identified a gasdermin family of pore-forming proteins that executes inflammasome-dependent and -independent pyroptosis1-5. Pyroptosis is proinflammatory, but its effect on antitumour immunity is unknown. Here we establish a bioorthogonal chemical system, in which a cancer-imaging probe phenylalanine trifluoroborate (Phe-BF3) that can enter cells desilylates and 'cleaves' a designed linker that contains a silyl ether. This system enabled the controlled release of a drug from an antibody-drug conjugate in mice. When combined with nanoparticle-mediated delivery, desilylation catalysed by Phe-BF3 could release a client protein-including an active gasdermin-from a nanoparticle conjugate, selectively into tumour cells in mice. We applied this bioorthogonal system to gasdermin, which revealed that pyroptosis of less than 15% of tumour cells was sufficient to clear the entire 4T1 mammary tumour graft. The tumour regression was absent in immune-deficient mice or upon T cell depletion, and was correlated with augmented antitumour immune responses. The injection of a reduced, ineffective dose of nanoparticle-conjugated gasdermin along with Phe-BF3 sensitized 4T1 tumours to anti-PD1 therapy. Our bioorthogonal system based on Phe-BF3 desilylation is therefore a powerful tool for chemical biology; our application of this system suggests that pyroptosis-induced inflammation triggers robust antitumour immunity and can synergize with checkpoint blockade.

A Wettability Contrast SERS Droplet Assay for Multiplexed Analyte Detection.

Droplet assay platforms have emerged as a significant methodology, providing distinct advantages such as sample compartmentalization, high throughput, and minimal analyte consumption. However, inherent complexities, especially in multiplexed detection, remain a challenge. We demonstrate a novel strategy to fabricate a plasmonic droplet assay platform (PDAP) for multiplexed analyte detection, enabling surface-enhanced Raman spectroscopy (SERS). PDAP efficiently splits a microliter droplet into submicroliter to nanoliter droplets under gravity-driven flow by wettability contrast between two distinct regions. The desired hydrophobicity and adhesive contrast between the silicone oil-grafted nonadhesive hydrophilic zone with gold nanoparticles is attained through (3-aminopropyl) triethoxysilane (APTES) functionalization of gold nanoparticles (AuNPs) using a scotch-tape mask. The wettability contrast surface facilitates the splitting of aqueous droplets with various surface tensions (ranging from 39.08 to 72 mN/m) into ultralow volumes of nanoliters. The developed PDAP was used for the multiplexed detection of Rhodamine 6G (Rh6G) and Crystal Violet (CV) dyes. The limit of detection for 120 nL droplet using PDAP was found to be 134 pM and 10.1 nM for Rh6G and CV, respectively. These results align with those from previously reported platforms, highlighting the comparable sensitivity of the developed PDAP. We have also demonstrated the competence of PDAP by testing adulterant spiked milk and obtained very good sensitivity. Thus, PDAP has the potential to be used for the multiplexed screening of food adulterants.

Poly(ferrocenylsilane)-Based Redox-Active Artificial Organelles for Biomimetic Cascade Reactions.

Artificial organelles serve as functional counterparts to natural organelles, which are primarily employed to artificially replicate, restore, or enhance cellular functions. While most artificial organelles exhibit basic functions, we diverge from this norm by utilizing poly(ferrocenylmethylethylthiocarboxypropylsilane) microcapsules (PFC MCs) to construct multifunctional artificial organelles through water/oil interfacial self-assembly. Within these PFC MCs, enzymatic cascades are induced through active molecular exchange across the membrane to mimic the functions of enzymes in mitochondria. We harness the inherent redox properties of the PFC polymer, which forms the membrane, to facilitate in-situ redox reactions similar to those supported by the inner membrane of natural mitochondria. Subsequent studies have demonstrated the interaction between PFC MCs and living cell including extended lifespans within various cell types. We anticipate that functional PFC MCs have the potential to serve as innovative platforms for organelle mimics capable of executing specific cellular functions.

Sea urchin nanostructured nickel cobaltite modified carbon cloth integrated wearable patches for the on-site detection of the immunosuppressant drug mycophenolate mofetil.

Mycophenolate mofetil (MpM) is a medication used to prevent the rejection of transplanted organs, particularly in kidney, heart, and liver transplant surgeries. It is extremely important to be conscious that MpM can raise the risk of severe infections and some cancers if it exceeds the recommended dose while lower doses will result in organ rejections. So, it is essential to monitor the dosage of MpM in real time in the micromolar range. In this work, we have synthesized 3-aminopropyltriethoxysilane (APTES) functionalized nickel cobaltite (NiCo2O4) and this amino functionalization was chosen to enhance the stability and electrochemical activity of NiCo2O4. The enhanced activity of NiCo2O4 was used for developing an electrochemical sensor for the detection of MpM. APTES functionalized NiCo2O4 was coated on carbon cloth and used as the working electrode. Surface functionalization with APTES on NiCo2O4 was aimed at augmenting the adsorption/interaction of MpM due to its binding properties. The developed sensor showed a very low detection limit of 1.23 nM with linear ranges of 10-100 nM and 1-100 µM and its practical applicability was examined using artificial samples of blood serum and cerebrospinal fluid, validating its potential application in real-life scenarios.

Sulfur Free Crosslinking of EPDM Composites via Silane Grafting and Silica Incorporation.

This study aims at evaluating and developing an environmental-friendly and sulfur-free cured ethylene propylene diene monomer (EPDM) composites. Silane grafted EPDM (SiEPDM) composites incorporated with silica is prepared via a solvent-free, one-step reactive mixing process. The silane grafting and silica filler bonding are characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The mechanical properties of the developed composites are examined. The fracture morphology is observed using an environmental scanning electron microscopy. The rheology and thermomechanical properties are evaluated by using a rotational rheometer and dynamic mechanical analyzer. Notably, a robust bonding between silica and the grafted silane is established, yielding a crosslinking network within the composite structure. This phenomenon is substantiated by the observed gel efficiency and rheology behavior. Consequently, a pronounced augmentation of up to 75% in tensile strength and 29% in tear strength are observed in the optimized SiEPDM-silica composites, distinguishing them from their EPDM-silica counterparts. The introduction of paraffin oil contributes to enhanced processability; however, it is concomitant with a reduction in gel efficiency and associated mechanical properties. Furthermore, subsequent UV weathering test unveils that the SiEPDM-silica composites exhibit the highest levels of residual tensile strength and modulus, indicative of their exceptional UV stability.

Cefixime loaded bare and functionalized halloysite nanocarriers and their biomedical applications.

Effective drug delivery for is the foremost requirement for the complete recovery of the disease. Nanomedicine and nanoengineering has provided so many spaces and ideas for the drug delivery design, whether controlled, targeted, or sustained. Different types of nanocarriers or nanoparticles are aggressively designed for the drug delivery applications. Clay minerals are identified as a one of the potential nanocarrier for the drug delivery. Owing to their biocompatibility and very low cytotoxicity, clay minerals showing effective therapeutic applications. In the present investigation, clay mineral, i.e., Halloysite nano tubes are utilized as a nanocarrier for the delivery of antibiotic cefixime (CFX), a third-generation cephalosporin. The HNT was first functionalized with the sulfuric acid and then further treated with the 3-(aminopropyl)triethoxysilane (APTES). The drug is loaded on three different classifications of HNTs, i.e., Bare-CFX-HNT, Acid-CFX-HNT, and APTES-CFX-HNT and their comparative analysis is established. Different characterization techniques such as X-ray diffractometry (XRD), Fourier transform infra-red (FT-IR), Transmission electron microscopy TEM), Brunauer-Emmett-Teller (BET), adsorption studies, and Thermogravimetric analysis (TGA) were performed to evaluate their chemical, structural, morphological, and thermal properties. TGA confirmed the encapsulation efficiency of Bare-CFX-HNT, Acid-CFX-HNT, and APTES-CFX-HNT as 42.65, 52.19, and 53.43%, respectively. Disk diffusion and MTT assay confirmed that the drug loaded HNTs have potential antibacterial activities and less cytotoxicity. The adsorption capacity of CFX with different HNTs are evaluated and Different adsorption and kinetic models have been discussed. Drug release studies shows that APTES-CFX-HNT showing sustained release of cefixime as compared to Bare-CFX-HNT and Acid-CFX-HNT.

Advancing fluorescence imaging: enhanced control of cyanine dye-doped silica nanoparticles.

BACKGROUND: Silica nanoparticles (SNPs) have immense potential in biomedical research, particularly in drug delivery and imaging applications, owing to their stability and minimal interactions with biological entities such as tissues or cells. RESULTS: With synthesized and characterized cyanine-dye-doped fluorescent SNPs (CSNPs) using cyanine 3.5, 5.5, and 7 (Cy3.5, Cy5.5, and Cy7). Through systematic analysis, we discerned variations in the surface charge and fluorescence properties of the nanoparticles contingent on the encapsulated dye-(3-aminopropyl)triethoxysilane conjugate, while their size and shape remained constant. The fluorescence emission spectra exhibited a redshift correlated with increasing dye concentration, which was attributed to cascade energy transfer and self-quenching effects. Additionally, the fluorescence signal intensity showed a linear relationship with the particle concentration, particularly at lower dye equivalents, indicating a robust performance suitable for imaging applications. In vitro assessments revealed negligible cytotoxicity and efficient cellular uptake of the nanoparticles, enabling long-term tracking and imaging. Validation through in vivo imaging in mice underscored the versatility and efficacy of CSNPs, showing single-switching imaging capabilities and linear signal enhancement within subcutaneous tissue environment. CONCLUSIONS: This study provides valuable insights for designing fluorescence imaging and optimizing nanoparticle-based applications in biomedical research, with potential implications for targeted drug delivery and in vivo imaging of tissue structures and organs.

Kinetic and thermodynamic studies on the thermal inactivation of lipase immobilized on glutaraldehyde-activated rice husk silica.

The objective of this study was to obtain sufficient information on the thermal stabilization of a food-grade lipase from Thermomyces lanuginosus (TLL) using the immobilization technique. To do this, a new non-porous support was prepared via the sequential extraction of SiO2 from rice husks, followed by functionalization with (3-aminopropyl) triethoxysilane - 3-APTES (Amino-SiO2), and activation with glutaraldehyde - GA (GA-Amino-SiO2). We evaluated the influence of GA concentration, which varied from 0.25% v v-1 to 4% v v-1, on the immobilization parameters and enzyme thermal stabilization. The thermal inactivation parameters for both biocatalyst forms (soluble or immobilized TLL) were calculated by fitting a non-first-order enzyme inactivation kinetic model to the experimental data. According to the results, TLL was fully immobilized on the external support surface activated with different GA concentrations using an initial protein load of 5 mg g-1. A sharp decrease of hydrolytic activity was observed from 216.6 ± 12.4 U g-1 to 28.6 ± 0.9 U g-1 of after increasing the GA concentration from 0.25% v v-1 to 4.0% v v-1. The support that was prepared using a GA concentration at 0.5% v v-1 provided the highest stabilization of TLL - 31.6-times more stable than its soluble form at 60 °C. The estimations of the thermodynamic parameters, e.g., inactivation energy (Ed), enthalpy (ΔH#), entropy (ΔS#), and the Gibbs energy (ΔG#) values, confirmed the enzyme stabilization on the external support surface at temperatures ranging from 50 to 65 °C. These results show promising applications for this new heterogeneous biocatalyst in industrial processes given the high catalytic activity and thermal stability.

Superhydrophobic coatings reduce human bacterial foodborne pathogen attachment to woods used in fresh produce harvest and postharvest packing.

Wood is reportedly more difficult to maintain in hygienic condition versus other food contact materials, yet its use in produce packing and retail warrants efforts to reduce the risk of microbial pathogen contamination and attachment. This study characterized antifouling capabilities of fluorinated silanes applied to wood used in fresh edible produce handling to render the wood superhydrophobic and less supportive of bacterial pathogen attachment. Pine and oak cubic coupon surfaces were treated with 1% (w/w) silane or left untreated. Treated and untreated coupons were inoculated with Salmonella enterica or Listeria monocytogenes and held to facilitate pathogen attachment for 1, 4, or 8 h. Silane treatment of wood produced significant reductions in the proportions of strongly attaching cells for both pathogens versus loosely attaching cells (P < 0.01). Salmonella attachment demonstrated a dependency on wood treatment; silane-treated wood supported a lower fraction of strongly adhering cells (1.87 ± 1.24 log CFU/cm2) versus untreated wood (3.72 ± 0.67 log CFU/cm2). L. monocytogenes demonstrated significant declines in strongly attaching cells during extended exposure to silane-treated wood, from 7.59 ± 0.14 to 5.27 ± 0.68 log CFU/cm2 over 8 h post-inoculation. Microscopic analysis demonstrated silane treatment increased the surface roughness of both woods, leading to superhydrophobic conditions on wood surfaces, consequently decreasing strong attachment of pathogenic bacteria.

Assessment of flusilazole residues on apples: Detection, quantification and health risk implications.

Apple, a major fruit of temperate Himalayas, is sprayed with chemical pesticides around 12 times during the cropping season. Various systemic and contact fungicides are applied for the management of major diseases. In order to manage disease, flusilazole 40 EC is frequently used. However, excessive chemical application has been found to be detrimental for consumer safety. Keeping in view consumer safety, risk assessment, the half-life and waiting period for flusilazole 40 EC were evaluated on the Red Velox variety of apple. The QuEChERS (quick, easy, cheap, effective, rugged and safe) method and high-performance liquid chromatography were adapted for sample processing and analysis, respectively. The recovery percentages of flusilazole at three fortification levels (0.04, 0.09 and 0.50 mg kg-1) were 98.85, 99.83 and 98.98%, respectively. Flusilazole at the recommended dose (80 g a.i. ha-1) left an initial deposit of 0.733 mg kg-1, which dissipated by 93.45% in 60 days and was non-detectable beyond this period. Meanwhile flusilazole at double the recommended dose (160 g a.i. ha-1) left an initial deposit of 0.913 mg kg-1, which dissipated by 93.43% in 70 days and was non-detectable beyond this period. Based on the maximum residue limit of 0.3 mg kg-1 as prescribed by the Codex Alimentarius Commission, a waiting period of 28.74 and 46.03 days was recorded for single and double doses, respectively. Moreover, in order to assess the consumer risk, theoretical maximum residue contributions (TMRCs) were derived using flusilazole residues (average and maximum) recorded at various time intervals and compared with the maximum permissible intake, which was found to be 0.42 mg per person per day. Based on the average per capita daily consumption of 6.76 g apple in India, the TMRC values were computed. Although the values of TMRC decreased below maximum permissible intake at the first day after application, indicating minimal consumer health risks, fruits sprayed with a double dose of flusilazole carried the risk even up to the tenth day after flusilazole application. The results of the present study will be valuable for safe and timely use of flusilazole on apple.

Identification and Fungicide Screening of Fungal Species Associated with Walnut Anthracnose in Shaanxi and Liaoning Provinces, China.

Walnut is cultivated around the world for its precious woody nut and edible oil. Recently, walnut infected by Colletotrichum spp. resulted in a great yield and quality loss. In August and September 2014, walnut fruits with anthracnose were sampled from two commercial orchards in Shaanxi and Liaoning provinces, and five representative isolates were used in this study. To identify the pathogen properly, four genes per region (internal transcribed spacer, glyceraldehyde-3-phosphate dehydrogenase, actin, and chitin synthase) were sequenced and used in phylogenetic studies. Based on multilocus phylogenetic analysis, five isolates clustered with Colletotrichum fioriniae, including its ex-type, with 100% bootstrap support. The results of multilocus phylogenetic analyses, morphology, and pathogenicity confirmed that C. fioriniae was one of the walnut anthracnose pathogens in China. All 13 fungicides tested inhibited mycelial growth and spore germination. Flusilazole, fluazinam, prochloraz, and pyraclostrobin showed the strongest suppressive effects on the mycelial growth than the others, the average EC50 values ranged from 0.09 to 0.40 µg/ml, and there was not any significant difference (P < 0.05). Pyraclostrobin, thiram, and azoxystrobin were the most effective fungicides on spore germination (P < 0.05), and the EC50 values ranged from 0.01 to 0.44 µg/ml. Pyraclostrobin, azoxystrobin, fluazinam, flusilazole, mancozeb, thiram, and prochloraz exhibited a good control effect on walnut anthracnose caused by C. fioriniae, and preventive activities were greater than curative activities. Pyraclostrobin at 250 a.i. µg/ml and fluazinam at 500 a.i. µg/ml provided the highest preventive and curative efficacy, and the values ranged from 81.3 to 82.2% and from 72.9 to 73.6%, respectively. As a consequence, mancozeb and thiram could be used at the preinfection stage, and pyraclostrobin, azoxystrobin, flusilazole, fluazinam, and prochloraz could be used at the early stage for effective prevention and control of walnut anthracnose caused by C. fioriniae. The results will provide more significant instructions for controlling the disease effectively in northern China.

A non-residue surface modification strategy for active-targeting fluorescent silica nanoparticles to cellular organelles.

Silica nanoparticles (SiNPs) with a chemically modified surface typically have a complicated chemical composition, which can significantly differ from their intended design. In this study, we systematically studied the effects of two surface modification methods on active-targeting of intracellular organelles of SiNPs: (1) the widely used step-by-step approach, which involves modifying SiNPs in two steps, i.e., the outer surface of SiNPs was firstly modified with amino groups and then these amino groups were linked with targeting groups, and (2) a newly developed one-step approach in which the ligand-silane complex is initially synthesized, followed by chemically immobilizing the complex on the surface of SiNPs. In the one-step approach, the molar ratio of reactants was precisely tuned so that there are no reactive groups left on the outer surface of SiNPs. Two essential organelles, mitochondria and the nucleus, were selected to compare the targeting performances of SiNPs synthesized via these two approaches. By characterizing physicochemical properties, including structural properties, the number of amino groups, surface charge, polydispersity, and cell colocalization, we demonstrated that SiNPs synthesized via the one-step approach with no residual linkage groups on their surface showed significantly improved mitochondria- and nucleus-targeting performances. This precise control of surface properties allows for optimized biological behavior and active-targeting efficiency of SiNPs. We anticipate that such simple and efficient synthetic strategies will enable the synthesis of effective SiNPs for active-targeting organelles in various biological applications.

Ultrasensitive electrochemical microRNA-21 detection based on MXene and ATRP photocatalytic strategy.

A Ti3C2TxMXene-based biosensor has been developed and the photocatalytic atom transfer radical polymerization (photo ATRP) amplification strategy applied to detect target miRNA-21 (tRNA). Initially, Ti3C2TxMXene nanosheets were synthesized from the Ti3AlC2 MAX precursor via selective aluminum etching. Then, functionalization of Ti3C2TxMXene nanosheets with 3-aminopropyl triethoxysilane (APTES) via silylation reactions to facilitate covalent bonding with hairpin DNA biomolecules specifically designed for tRNA detection. Upon binding with the tRNA, the hairpin DNA liberated the azide (N3) group, initiating a click reaction to affix to the photo ATRP initiator. Through the ATRP photoreaction, facilitated by an organic photoredox catalyst and light, a significant amount of ferrocenyl methyl methacrylate (FMMA) monomer was immobilized on the electrode. Therefore, the electrochemical signal is amplified. The electrochemical efficacy of the biosensor was assessed using square wave voltammetry (SWV). Under optimized conditions, the biosensor demonstrated remarkable sensitivity in detecting tRNA, with a linear detection range from 0.01 fM to 10 pM and a detection limit of 2.81 aM. The findings elucidate that the developed biosensor, in conjunction with the photo ATRP strategy, offers reproducibility, stability, and increased sensitivity, underscoring its potential applications within the experimental medical sector of the biomolecular industry.

Effect of water glass treatment for zirconia and silane coupling on bond strength of resin cement.

OBJECTIVE: To evaluate the ability of the water glass treatment to penetrate zirconia and improve the bond strength of resin cement. MATERIAL AND METHODS: Water glass was applied to zirconia specimens, which were then sintered. The specimens were divided into water-glass-treated and untreated zirconia (control) groups. The surface properties of the water-glass-treated specimens were evaluated using surface roughness and electron probe micro-analyser (EPMA) analysis. A resin cement was used to evaluate the tensile bond strength, with2 and without a silane-containing primer. After 24 h in water storage at 37 °C and thermal cycling, the bond strengths were statistically evaluated with t-test, and the fracture surfaces were observed using SEM. RESULTS: The water glass treatment slightly increased the surface roughness of the zirconia specimens, and the EPMA analysis detected the water glass penetration to be 50 µm below the zirconia surface. The application of primer improved the tensile bond strength in all groups. After 24 h, the water-glass-treated zirconia exhibited a tensile strength of 24.8 ± 5.5 MPa, which was significantly higher than that of the control zirconia (17.6 ± 3.5 MPa) (p < 0.05). After thermal cycling, the water-glass-treated zirconia showed significantly higher tensile strength than the control zirconia. The fracture surface morphology was mainly an adhesive pattern, whereas resin cement residue was occasionally detected on the water-glass-treated zirconia surfaces. CONCLUSION: The water glass treatment resulted in the formation of a stable silica phase on the zirconia surface. This process enabled silane coupling to the zirconia and improved the adhesion of the resin cement.

Effect of surface treatment strategies on bond strength of additively and subtractively manufactured hybrid materials for permanent crowns.

OBJECTIVES: The purpose of this study is to evaluate the bond strength of different computer-aided design / computer-aided manufacturing (CAD/CAM) hybrid ceramic materials following different pretreatments. METHODS: A total of 306 CAD/CAM hybrid material specimens were manufactured, n = 102 for each material (VarseoSmile Crownplus [VSCP] by 3D-printing; Vita Enamic [VE] and Grandio Blocs [GB] by milling). Each material was randomly divided into six groups regarding different pretreatment strategies: control, silane, sandblasting (50 µm aluminum oxide particles), sandblasting + silane, etching (9% hydrofluorics acid), etching + silane. Subsequently, surface roughness (Ra) values, surface free energy (SFE) were measured. Each specimen was bonded with a dual-cured adhesive composite. Half of the specimens were subjected to thermocycling (5000 cycles, 5-55 °C). The shear bond strength (SBS) test was performed. Data were analyzed by using a two-way analysis of variance, independent t-test, and Mann-Whitney-U-test (α = 0.05). RESULTS: Material type (p = 0.001), pretreatment strategy (p < 0.001), and the interaction (p < 0.001) all had significant effects on Ra value. However, only etching on VSCP and VE surface increased SFE value significantly. Regarding SBS value, no significant difference was found among the three materials (p = 0.937), while the pretreatment strategy significantly influenced SBS (p < 0.05). Etching on VSCP specimens showed the lowest mean value among all groups, while sandblasting and silane result in higher SBS for all test materials. CONCLUSIONS: The bond strength of CAD/CAM hybrid ceramic materials for milling and 3D-printing was comparable. Sandblasting and silane coupling were suitable for both millable and printable materials, while hydrofluoric etching should not be recommended for CAD/CAM hybrid ceramic materials. CLINICAL RELEVANCE: Since comparable evidence between 3D-printable and millable CAD/CAM dental hybrid materials is scarce, the present study gives clear guidance for pretreatment planning on different materials.

Modified mesoporous silica derived from bamboo leaf using cetyltrimethylammonium bromide and 3-aminopropyl triethoxysilane as CO2 adsorbent in biogas purification.

The calorific value of post-fermentation biogas is a way down below standard and quite low due to the presence of high amount level of carbon dioxide (CO2) biogas mixture. Therefore, it raises the need to process the biogas, separating it from CO2 in order to obtain high-purity biogas as well as to maximize its calorific value. One widely available material that can be used as a sustainable carbon capture adsorbent is silica extracted from bamboo leaves. However, so that silica can act as CO2 adsorber, it is necessary to modify the surface of silica with CTAB and APTES (3-aminopropyl triethoxysilane). In this study, 2-stage method was carried out, namely preparation of mesoporous silica and surface modification using APTES on the mesoporous silica. Experiments in synthesizing APTES-modified silica were obtained by varying its composition: CTAB (1.5-5%w), (HCl 1.5-5 N), and APTES (10-30%). A central composite design (CCD) was employed in exploring the interaction between all variables and also performed for the optimization. Through analysis of variance, it shows that optimum CO2 adsorption capacity reaches 47.02 mg g-1, by applying 4.98% of CTAB, 4.28 N of HCl and 10.08% of APTES. Pseudo-second-order kinetic and Redlich-Peterson isotherm models are more representative to show the adsorption behavior of CO2 into the modified silica. The results show that the modified silica with APTES shows a prospective application of silica for CO2 removal from biogas.

Optimization of Surface Functionalizations for Ring Resonator-Based Biosensors.

Liquid biopsy is expected to become widespread in the coming years thanks to point of care devices, which can include label-free biosensors. The surface functionalization of biosensors is a crucial aspect that influences their overall performance, resulting in the accurate, sensitive, and specific detection of target molecules. Here, the surface of a microring resonator (MRR)-based biosensor was functionalized for the detection of protein biomarkers. Among the several existing functionalization methods, a strategy based on aptamers and mercaptosilanes was selected as the most highly performing approach. All steps of the functionalization protocol were carefully characterized and optimized to obtain a suitable protocol to be transferred to the final biosensor. The functionalization protocol comprised a preliminary plasma treatment aimed at cleaning and activating the surface for the subsequent silanization step. Different plasma treatments as well as different silanes were tested in order to covalently bind aptamers specific to different biomarker targets, i.e., C-reactive protein, SARS-CoV-2 spike protein, and thrombin. Argon plasma and 1% v/v mercaptosilane were found as the most suitable for obtaining a homogeneous layer apt to aptamer conjugation. The aptamer concentration and time for immobilization were optimized, resulting in 1 µM and 3 h, respectively. A final passivation step based on mercaptohexanol was also implemented. The functionalization protocol was then evaluated for the detection of thrombin with a photonic biosensor based on microring resonators. The preliminary results identified the successful recognition of the correct target as well as some limitations of the developed protocol in real measurement conditions.

Effect of different surface treatment protocols on the bond strength between lithium disilicate and resin cements.

Because the use of hydrofluoric acid (HF) poses health risks if handled improperly, many clinicians prefer to have the ceramic restorations pre-etched in dental laboratories. However, during the try-in procedure, the pre-etched glass-ceramic restorations may be contaminated with saliva resulting in reduced bond strength. This in-vitro study aimed to investigate the effect of different surface treatments on the bond strength of lithium disilicate (LD) glass-ceramic restorations (IPS e.max Press, Ivoclar Vivadent) to two resin cements. One-hundred eighty blocks (4X4X3mm) of LD glass-ceramic were divided into twelve groups (n = 15), of which six received Variolink Esthetic DC (VE) cement and six received RelyX Ultimate (RU) cement, following the surface treatments: G1) Control: Hydrofluoric Acid + Silane (HF + Sil); G2) Hydrofluoric Acid + Saliva + Silane (HF + S + Sil); G3) Hydrofluoric Acid + Saliva + Ivoclean + Silane (HF + S + IC + Sil); G4) Hydrofluoric Acid + Saliva + Phosphoric Acid + Silane (HF + S + P + Sil); G5) Hydrofluoric Acid + Saliva + Monobond Etch & Prime (HF + S + EP); G6) Monobond Etch & Prime (EP). Following treatment, a resin-cement cylinder (2.3 mm diameter) was built on the glass-ceramic surface, photocured (20 s), stored in distilled water (37 °C, 24 h) and submitted to the shear bond strength test. Bond strength data (MPa) were subjected to two-way ANOVA and Tukey (α = 0.01). Cement type and surface treatment had a significant effect on the bond strength (p < 0.001) (Table 4). Single-step Monobond Etch & Prime (EP) significantly improved the bond strength of resin-cements to glass-ceramic with and without saliva contamination.

Influence of universal adhesives and silane coupling primer on bonding performance to CAD-CAM resin-based composites: A laboratory investigation.

OBJECTIVE: Obtaining strong resin bonds to computer-aided design and computer-aided manufacturing (CAD-CAM) resin-based composites with dispersed fillers (CCRBCs) poses a challenge. Therefore, this study aimed to assess the effect of three universal adhesives and a two-component silane coupling agent on the shear bond strength to three (CCRBCs). MATERIALS AND METHODS: Eight hundred and sixty-four specimens of Brilliant Crios, Lava Ultimate, and Tetric CAD were polished or grit blasted, bonded with Adhese Universal DC, One Coat 7 Universal (OC7), and Scotchbond Universal Plus Adhesive (SBU) with or without a silane primer. Shear bond strength was measured after 24 h and 10,000 thermocycles. Linear regressions were performed (α = 0.05). RESULTS: After thermocycling, bond strengths were similar for the universal adhesives on polished Brilliant Crios and Lava Ultimate (p ≥ 0.408). Grit blasted Tetric CAD showed no significant differences (p ≥ 0.096). The silane primer had minimal impact on grit blasted Tetric CAD (p ≥ 0.384). The silane primer increased the bond strength of OC7 to Brilliant Crios (p = 0.001) but decreased the adhesion of SBU to Brilliant Crios and Lava Ultimate (p ≤ 0.018). CONCLUSIONS: Bond strength of universal adhesives varied with CCRBC type. The two-component silane coupling agent showed mixed effects on adhesive performance. CLINICAL SIGNIFICANCE: Selecting universal adhesives from the same CCRBC product line does not always guarantee superior bond strength. The efficacy of silane coupling agents differs based on the bonding substrate.

The Facile Synthesis and Application of Mesoporous Silica Nanoparticles with a Vinyl Functional Group for Plastic Recycling.

Due to growing concerns about environmental pollution from plastic waste, plastic recycling research is gaining momentum. Traditional methods, such as incorporating inorganic particles, increasing cross-linking density with peroxides, and blending with silicone monomers, often improve mechanical properties but reduce flexibility for specific performance requirements. This study focuses on synthesizing silica nanoparticles with vinyl functional groups and evaluating their mechanical performance when used in recycled plastics. Silica precursors, namely sodium silicate and vinyltrimethoxysilane (VTMS), combined with a surfactant, were employed to create pores, increasing silica's surface area. The early-stage introduction of vinyl functional groups prevented the typical post-synthesis reduction in surface area. Porous silica was produced in varying quantities of VTMS, and the synthesized porous silica nanomaterials were incorporated into recycled polyethylene to induce cross-linking. Despite a decrease in surface area with increasing VTMS content, a significant surface area of 883 m2/g was achieved. In conclusion, porous silica with the right amount of vinyl content exhibited improved mechanical performance, including increased tensile strength, compared to conventional porous silica. This study shows that synthesized porous silica with integrated vinyl functional groups effectively enhances the performance of recycled plastics.