Multidimensional Ultrasound Evaluation of Diastasis Recti Abdominis During Different Gestational Periods.

OBJECTIVE: The purpose of this study is to explore the application value of two-dimensional ultrasound and shear wave elastography (SWE) in the multidimensional evaluation of diastasis recti abdominis (DRA) during different gestational periods. METHODS: A cohort of 202 gravidas that were examined in our hospital between June 2021 and September 2022 were selected for the purpose of the study, which included 26 cases with <14 weeks of pregnancy, 36 cases in the 14th-27th week of pregnancy, 36 cases in the 28th-34th week of pregnancy, 32 cases in the 35th-38th week of pregnancy, 45 cases at 42 days postpartum, and 27 cases at 3 months postpartum. The inter-rectus distance (IRD) and the thickness in each gestational period were measured, and Young's modulus of the rectus abdominis at different gestational periods was measured using SWE by two sonographers. The differences in IRD, thickness, and elasticity characteristics during different periods, and the correlation between rectus abdominis elasticity and IRD, thickness, body mass index (BMI), neonatal weight, and delivery mode were analyzed and compared. The consistency of SWE parameters obtained by different sonographers was also compared. RESULTS: There were significant differences in IRD, thickness, and Young's modulus during different gestational periods (P = .000, P < .001, P < .001). Early postpartum IRD and Young's modulus did not restore to the level of early pregnancy (P < .001, P < .001), while the thickness of rectus abdominis was not significantly different from that of early pregnancy (P = .211). The Young's modulus of rectus abdominis was negatively correlated with the IRD (r = .515), positively correlated with the thickness of rectus abdominis (r = .408), and weakly negatively correlated with maternal BMI (r = -.296). There was no significant correlation with neonatal weight or delivery mode (P = .147, .648). The Bland-Altman plot showed that the two sonographers had good consistency in evaluating the elasticity of rectus abdominis by SWE. CONCLUSION: The multidimensional evaluation of DRA by ultrasound is feasible and IRD and Young's modulus can be used to evaluate the postpartum recovery of DRA. The combination of the two can objectively reflect the severity of DRA morphology and function.

Inhibitory mechanism of n-MTAB AuNPs for α-synuclein aggregation.

OBJECTIVE: The aggregation of alpha-synuclein (α-syn) is closely related to the pathogenesis and dysfunction of Parkinson's disease. METHODS: To investigate the potential of nanoparticlemediated therapy, the interactive mechanism between α-syn and n-myristyltrimethylammonium bromide (MTAB) Gold nanoparticles (AuNPs) with different diameters was explored by molecular dynamics simulations. RESULTS: The results indicated that there was a directional interaction between α-syn and n-MTAB AuNPs, in which the driving force for the binding of the C-terminus in α-syn came from electrostatic interactions and the nonamyloid ß component (NAC) domain exhibited weak hydrophobic interactions as well as electrostatic interaction, thereby preventing α-syn aggregation. Energy statistics and analysis showed that for 5-MTAB AuNPs, acidic amino acids such as Glu and Asp played a very important role. CONCLUSIONS: This study not only demonstrated a theoretical foundation for the behavior of biomolecules directionally adsorbed on the surface of biofunctional nanoparticles but also indicated that 5-MTAB AuNPs may be a potential inhibitor against α-syn protein aggregation.

Biological effect of black phosphorus nanosheets on the interaction between SARS-CoV-2 S protein and ACE2.

The binding of the spike glycoprotein (S protein) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to angiotensin-converting enzyme 2 (ACE2) is the main pathway that leads to serious coronavirus disease 2019 (COVID-19) infection. In the biomedical applications of various nanomaterials, black phosphorus nanosheets (BP) have been receiving increasing attention owing to their excellent characteristics. In this study, the biological effect of BP on the interaction between the S protein and ACE2 was investigated by molecular dynamics simulations. The results indicated that the ACE2 could be quickly and stably adsorbed on the BP surface by non-specific binding and retain its structural integrity. Compared with the case without BP, the interaction of the S protein bound to ACE2 adsorbed on the BP surface was greatly weakened, including hydrogen bonds, salt bridges, and van der Waals forces. This study not only reveals that BP could effectively obstruct the binding of S protein and ACE2, which may provide a potential and reasonable drug carrier to further enhance the curative effect of inhibitors against SARS-CoV-2 infection, but also presents a novel interference mechanism for protein-protein interactions caused by nanomaterials.

Regulation effects of hydrogen sulfide on ascorbate-glutathione cycle in naked oat leaves under saline-alkali stress.

Saline-alkali stress is one of the common abiotic stresses for plants. Hydrogen sulfide (H2S), as a gas signal, plays an important role in driving the responses of plants to saline-alkali stress. To explore the regulating effects of H2S on the ascorbate (AsA)-glutathione (GSH) cycle in naked oat (Avena nude) under saline-alkali stress, we used sodium hydrogen sulfide (NaHS) as donor of exogenous H2S and hydroxylamine (HA) as H2S synthesis inhibitor to examine the effects of H2S on plant growth, leaf reactive oxygen species, membrane lipid peroxidation, and antioxidants and key enzymes in the AsA-GSH cycle in "Dingyou 9" variety of naked oat under saline-alkali mixed stress. Results showed that spraying 50 µmol·L-1 NaHS could alleviate the inhibition of 50 mmol·L-1 saline-alkali mixed stress on the growth of naked oats, reduce the content of superoxide anions, H2O2, malondialdehyde, oxidized ascorbate (DHA), glutathione (GSH), and oxidized glutathione (GSSG) in leaves of naked oat under saline-alkali mixed stress, increase the ratio of AsA/DHA and GSH/GSSG, but did not affect the content of reduced ascorbic acid (AsA). Spraying NaHS significantly increased the activities of key enzymes, L-galactose dehydrogenase (GalDH) and L-galactono-1, 4-lactone dehydrogenase (GalLDH), for AsA synthesis pathways in naked oat leaves under salt-alkali mixed stress, as well as monodehydroascorbate reductase (MDHAR) in the AsA-GSH cycle, and decreased the activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), but did not affect the activities of ascorbate oxidase (AO) and glutathione reductase (GR). The addition of HA partially or completely relieved those aforementioned effects. Our results indicated that H2S could increase the efficiency of AsA-GSH cycle by promoting the synthesis of AsA and enhancing the activity of MDHAR, and reduce the oxidative damage of saline-alkali stress to naked oats.

Selective inhibition mechanism of nitroxoline to the BET family: Insight from molecular simulations.

Although the proteins in bromodomain and extra-terminal domain (BET) family are promising therapy drug targets for numerous human diseases, the binding effectiveness is interfered by the competition from non-BET protein BRD9. In this study, molecular docking, molecular dynamics simulations, binding free energy calculations and per-residue energy decomposition methods were employed to clarify the selective inhibition mechanism of nitroxoline. The results showed that the different cavity volume of effective embedding inhibitor and the changes in conserved residues were associated with the significant higher selectivity of inhibitor nitroxoline for BET family than non-BET protein (BRD9). In addition, the non-polar interactions occurred in Phe83, Val87 at ZA loop, and the polar interaction appeared in Met132, Asn135 at BC loop. Therefore, when designing a new inhibitor, it could better improve the inhibitor activity by introducing the heteroatom conjugated pyridine-like moiety and the strong electron-withdrawing nitro-like moiety. Overall, this study not only clarified the molecular mechanism of the selective inhibition of nitroxoline, but also provided insight into designing more effective BET inhibitors in next step.

Tailoring Crystal Facets of Metal-Organic Layers to Enhance Photocatalytic Activity for CO2 Reduction.

It is common that different crystal facets in metal and metal oxide nanocrystals display different catalytic performances, whereas such phenomena have been rarely documented in metal-organic frameworks (MOFs). Herein, we demonstrate for the first time that a nickel metal-organic layer (MOL) exposing rich (100) crystal facets (Ni-MOL-100) shows a much higher photocatalytic CO2 -to-CO activity than the one exposing rich (010) crystal facets (Ni-MOL-010) and its bulky counterpart (bulky Ni-MOF), with a catalytic activity up to 2.5 and 4.6 times more active than Ni-MOL-010 and bulky Ni-MOF, respectively. Theoretical studies reveal that the two coordinatively unsaturated NiII ions with a close distance of 3.50 Šon the surface of Ni-MOL-100 enables synergistic catalysis, leading to more favorable energetics in CO2 reduction than that of Ni-MOL-010.

Study of the controversial resveratrol that interact with the endogenous glutathione thiyl radical in cancer cells.

Found in various natural food products, many in vitro evidence indicated that resveratrol (RES) has been linked to neuroprotective and cardioprotective effects and prevent cancer development. However, human clinical trials have been conducted with varying results, making the usage of RES controversial. In this paper, we demonstrated that the drug RES could be conjugated with the high levels of endogenous GS• in cancer cells. 5,5-Dimethyl-1-Pyrroline-N-Oxide (DMPO) was employed to capture the GS•. The molecular mechanism of the reaction between RES and GS• was further studied by UV-Vis spectrometry, mass spectrometry and Density Functional Theory (DFT) calculations. Besides, the formation of the adduct GS-RES in cancer cell was obtained when RES was added during incubation. Further study indicated that over 77.6% of the RES was consumed in cancer cells. This study suggested that endogenous GS• may be one of the important factors to cause the depletion of anti-tumour drugs during chemotherapy, which should be paid special attention in clinical therapeutics and drug development.

Distinct Expression of the Two NO-Forming Nitrite Reductases in Thermus antranikianii DSM 12462T Improved Environmental Adaptability.

Hot spring ecosystems are analogous to some thermal environments on the early Earth and represent ideal models to understand life forms and element cycling on the early Earth. Denitrification, an important component of biogeochemical nitrogen cycle, is highly active in hot springs. Nitrite (NO2-) reduction to nitric oxide (NO) is the significant and rate-limiting pathway in denitrification and is catalyzed by two types of nitrite reductases, encoded by nirS and nirK genes. NirS and NirK were originally considered incompatible in most denitrifying organisms, although a few strains have been reported to possess both genes. Herein, we report the functional division of nirS and nirK in Thermus, a thermophilic genus widespread in thermal ecosystems. Transcriptional levels of nirS and nirK coexisting in Thermus antranikianii DSM 12462T were measured to assess the effects of nitrite, oxygen, and stimulation time. Thirty-nine Thermus strains were used to analyze the phylogeny and distribution of nirS and nirK; six representative strains were used to assess the denitrification phenotype. The results showed that both genes were actively transcribed and expressed independently in T. antranikianii DSM 12462T. Strains with both nirS and nirK had a wider range of nitrite adaptation and revealed nir-related physiological adaptations in Thermus: nirK facilitated adaptation to rapid changes and extended the adaptation range of nitrite under oxygen-limited conditions, while nirS expression was higher under oxic and relatively stable conditions.

One-pot facile synthesis of CuNCs/RGO nanocomposite for the sensitive detection of heparin in human serum samples.

A simple and facile one-pot approach for the synthesis of copper nanoclusters decorated reduced graphene oxide (CuNCs/RGO) nanocomposite was proposed, in which the CuNCs attached to the surface of the reduced glutathione (GSH) functionalized RGO through ligand exchange via their thiol functionalities. The synthesized nanocomposite was verified by structural characterizations, and the further investigation of density functional theory (DFT) indicated that Cu3R2 cluster (R = C10H16O6N3S) with the lowest energy was the most stable structure in GSH-capped CuNCs. Although the CuNCs/RGO nanocomposite exhibited rather weak fluorescence, with the addition of heparin (Hep), the significant enhancement of fluorescence at 595 nm was achieved, which was developed to detect Hep in human serum samples with high selectivity and sensitivity. The mechanisms of fluorescence quenching of CuNCs/RGO nanocomposite and the sensing of Hep were discussed. The linear range was 0.1-10 µM with the detection limit of 26 nM in buffer solution containing 2% human serum sample, and satisfactory recovery in the range of 96.6%-104% was obtained, suggesting that the proposed method could applied to the detection of Hep in human serum samples.

The binding mechanism of nitroreductase fluorescent probe: Active pocket deformation and intramolecular hydrogen bonds.

Nitroreductase (NTR), a member of the flavoenzyme family, could react with nicotinamide adenine dinucleotide by reducing nitro to amino at hypoxic tumor, which can be monitored by some fluorescent probes in vivo. Here, molecular docking and molecular dynamics simulation techniques were used to explore the molecular mechanisms between NTR and probes. The results showed that formation of hydrogen bond in 1F5V-13 between A@His215 and B@Ser41 with 74.53% occupancy might be the main reason for the decrease of probe fluorescence emission in experiment. Moreover, Probe 16 was rotated by nearly 60 degrees with respect to the position of other probes in protein binding pocket, deforming the protein active pocket, changing the hydrogen bond formation, which leads to the fluorescence performance of 16 with electron donor and electron acceptor groups was superior to other probes in experiment. The deformation of protein active pocket and the formation of intramolecular hydrogen bonds revealed the difference in performance of NTR fluorescent probe at molecular level, which provide theoretical guidance for latter design of fluorescent probes with better performance.

A novel thermal Cas12b from a hot spring bacterium with high target mismatch tolerance and robust DNA cleavage efficiency.

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated proteins (Cas), such as Cas9 and Cpf1, are RNA-guided endonucleases that target and degrade nucleic acids, providing powerful genomic editing and molecular diagnostic tools. Cas12b enzymes are distinct effectors; however, their features and catalytic boundaries require further characterization. We identified BrCas12b from the thermophile bacterium Brevibacillus sp. SYSU G02855 as a novel ortholog of cas12b. Biochemical analyses revealed that BrCas12b is a dual-RNA-guided endonuclease with higher optimum reaction temperature than that of other reported members of Cas12b. The seed sequence of BrCas12b is only 4 nt in length, indicating that it has greater target mismatch tolerance than that of previously reported Cas effectors; however, it contains a compensatory effect at the position of the cleavage site. Using fluorescence-based detection method to evaluate target cleavage efficiency, we showed that BrCas12b has robust enzymatic cleavage activity (Kcat/Km (s-1 M-1) = 8.80 × 1011), which is significantly higher than that of AacCas12b (Kcat/Km (s-1 M-1) = 7.56 × 108) from Alicyclobacillus acidoterrestris. The results increase our understanding of the catalytic mechanism of Cas12b family members and suggest that BrCas12b might be useful in the application of genomic editing and molecular diagnosis.

An Ultrasound Model to Predict the Short-Term Effects of Endovascular Stent Placement in the Treatment of Carotid Artery Stenosis.

Purpose: The present study aimed to explore the predictive ability of an ultrasound linear regression equation in patients undergoing endovascular stent placement (ESP) to treat carotid artery stenosis-induced ischemic stroke. Methods: Pearson's correlation coefficient of actual improvement rate (IR) and 10 preoperative ultrasound indices in the carotid arteries of 64 patients who underwent ESP were retrospectively analyzed. A predictive ultrasound model for the fitted IR after ESP was established. Results: Of the 10 preoperative ultrasound indices, peak systolic velocity (PSV) at stenosis was strongly correlated with postoperative actual IR (r = 0.622; P < 0.01). The unstable plaque index (UPI; r = 0.447), peak eccentricity ratio (r = 0.431), and plaque stiffness index (ß; r = 0.512) moderately correlated with actual IR (P < 0.01). Furthermore, the resistance index (r = 0.325) and the dilation coefficient (r = 0.311) weakly correlated with actual IR (P < 0.05). There was no significant correlation between actual IR and the number of unstable plaques, area narrowing, pulsatility index, and compliance coefficient. In combination, morphological, hemodynamic, and physiological ultrasound indices can predict 62.39% of neurological deficits after ESP: fitted IR = 0.9816 - 0.1293ß + 0.0504UPI - 0.1137PSV. Conclusion: Certain carotid ultrasound indices correlate with ESP outcomes. The multi-index predictive model can be used to evaluate the effects of ESP before surgery.

Study on Biocompatibility of AuNPs and Theoretical Design of a Multi-CDR-Functional Nanobody.

The investigation on proteinlike specific functions of nanoparticles (NPs) has been a huge challenge. Here, the biocompatibility of Au nanoparticles (AuNPs) to antigens hen egg white lysozyme and epidermal growth factor receptor was studied first by molecular dynamics (MD) simulations and the research results revealed that antigens could form quickly a stable binding with the AuNPs and kept the structural integrity of the protein, which demonstrated better biocompatibility of AuNPs. Then, two types of complementary-determining regions (CDRs) were grafted onto the AuNPs to design a novel multi-CDR-functional nanobody. By means of MD simulations under physiological conditions, we found that the bindings of the designed nanobody and the antigens were stable and safe. Compared with the results of antigens interacting with the natural antibody, the redundant CDRs on AuNPs bound with the nonactive site in the antigens to form a stable conformation, which leaded to the powerful binding capacity of the designed nanobody than that of the natural antibody. This study provided available insights into the biocompatibility of AuNPs and important theoretical proofs to the multi-CDR-functional nanobody applied in biological systems, which were expected to help in design of novel multifunctional nanobodies.

Molecular mechanism study of several inhibitors binding to BRD9 bromodomain based on molecular simulations.

Bromodomain-containing protein 9 (BRD9) has been employed as a potential target for anticancer drugs in recent years. In this work, molecular docking, molecular dynamics (MD) simulations, binding free energy calculations, and per residue energy decomposition approaches were performed to elucidate the different binding modes between four pyridinone-like scaffold inhibitors and BRD9 bromodomain. Analysis results indicate that non-polar contribution mainly deriving from van der Waals energy is a critical impact on binding affinity of inhibitors against BRD9. Some key residues Phe44, Phe47, Val49, and Ile53 (at ZA loop) enhance the binding energy of inhibitors in BRD9 by means of providing hydrophobic interactions. Moreover, it is observed that BRD9 is anchored by the formation of a stable hydrogen bond between the carbonyl of the inhibitors and the residue Asn100 (at BC loop), and a strong π-π stacking interaction formed between the residue Tyr106 (at BC loop) and the inhibitors. The existence of dimethoxyphenyl structure and the aromatic ring merged to pyridinone scaffold are useful to enhance the BRD9 binding affinity. These findings should guide the rational design of more prospective inhibitors targeting BRD9. Communicated by Ramaswamy H. Sarma.

Molecular inhibitory mechanism study on the potent inhibitor brigatinib against four crizotinib-resistant ALK mutations.

As a potent and selective drug, brigatinib exhibits high efficacy against wild-type and mutant anaplastic lymphoma kinase (ALK) proteins to treat non-small cell lung cancer. In this work, the mechanisms of brigatinib binding to wild type and four mutant ALKs were investigated to gain insight into the dynamic energetic and structural information with respect to the design of novel inhibitors. Comparison between ALK-brigatinib and ALK-crizotinib suggests that the scaffold of brigatinib is well anchored to the residue Met1199 of hinge region by two hydrogen bonds, and the residue Lys1150 has the strong electrostatic interaction with the dimethylphosphine oxide moiety in brigatinib. These ALK mutations have significant influences on the flexibility of P-loop region and DFG sequences, but do not impair the hydrogen bonds between brigatinib and the residue Met1199 of hinge region. And mutations (L1196M, G1269A, F1174L, and R1275Q) induce diverse conformational changes of brigatinib and the obvious energy variation of residues Glu1167, Arg1209, Asp1270, and Asp1203. Together, the detailed explanation of mechanisms of those mutations with brigatinib further provide several guidelines for the development of more effective ALK inhibitors.

Molecular mechanisms of tetrahydropyrrolo[1,2-c]pyrimidines as HBV capsid assembly inhibitors.

As an attractive therapeutic strategy for chronic hepatitis B virus (HBV), HBV capsid assembly inhibitors have got increased attention, which induce aberrant capsid assembly and thereby affect viral replication. In this work, molecular docking, molecular dynamics simulations, binding free energy calculations and per-residue energy decomposition were implemented to investigate the binding mechanism between tetrahydropyrrolopyrimidines scaffold inhibitors and HBV capsid protein. The obtained results displayed that the non-polar interaction, hydrogen bond interaction, polar interaction and π-π stacking interaction together help to stabilize the conformation of inhibitors in the interface of HBV core proteins, and residues Pro25, Thr33, Trp102, Ile105, Tyr118, Ile139, Leu140 (chain B), and Val124, Trp125, Thr128, Arg133 (chain C) were important participants during binding process. The replacement of the electronegative groups F, Cl and sulphonamide in inhibitor 28a would alter the major inhibitory effects of binding and activation. The models established by three-dimensional quantitative structure-activity relationship could be used to predict the anti-HBV activities of the tetrahydropyrrolopyrimidines molecules. This study will help understanding the molecular mechanisms and novel designed small molecules could act as better inhibitors.

Extraction of nickel from NiFe-LDH into Ni2P@NiFe hydroxide as a bifunctional electrocatalyst for efficient overall water splitting.

The development of highly efficient, low-cost and stable electrocatalysts for overall water splitting is highly desirable for the storage of intermittent solar energy and wind energy sources. Herein, we show for the first time that nickel can be extracted from NiFe-layered double hydroxide (NiFe-LDH) to generate an Ni2P@FePO x heterostructure. The Ni2P@FePO x heterostructure was converted to an Ni2P@NiFe hydroxide heterostructure (P-NiFe) during water splitting, which displays high electrocatalytic performance for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1.0 M KOH solution, with an overpotential of 75 mV at 10 mA cm-2 for HER, and overpotentials of 205, 230 and 430 mV at 10, 100 and 1000 mA cm-2 for OER, respectively. Moreover, it could afford a stable current density of 10 mA cm-2 for overall water splitting at 1.51 V in 1.0 M KOH with long-term durability (100 h). This cell voltage is among the best reported values for bifunctional electrocatalysts. The results of theoretical calculations demonstrate that P-NiFe displays optimized adsorption energies for both HER and OER intermediates at the nickel active sites, thus dramatically enhancing its electrocatalytic activity.

Antiferromagnetic Interfacial Coupling and Giant Magnetic Hysteresis in La0.5Ca0.5MnO3-SrRuO3 Superlattices.

Superlattices are of great importance due to their potential as new materials genome to synthesize new functional materials. Thus, tuning of the ground state of superlattices is crucial to further control their physical properties. In this study, superlattices (SLs) consisting of alternating layers of SrRuO3 (SRO) (5 nm) and La0.5Ca0.5MnO3 (LCMO) (5 nm) are epitaxially grown on SrTiO3 (STO) and LaAlO3 (LAO) substrates with 10-unit-cell periods. A variation in the substrate-induced-strain for this choice of SLs triggers observation of remarkable properties, such as magnetic anisotropy and large magnetic hysteresis. The strain states experienced by LCMO and SRO in these SLs result in strong ferromagnetic interlayer coupling and weak antiferromagnetic interlayer coupling at low temperatures in SLs of LCMO-SRO/STO and a strong antiferromagnetic interlayer coupling in SLs of LCMO-SRO/LAO. Besides, a large magnetic hysteresis resulting from the predominant magnetic anisotropy of SRO together with the strength of magnetic coupling is observed in SLs of LCMO-SRO/LAO along the out-of-plane direction of the LAO substrate. These four different magnetic behaviors along four different directions of substrate orientations are interpreted in terms of preferential orbital occupation and competing magnetic exchange coupling together with magnetic anisotropy. This study demonstrates the subtleties in controlling the strength of magnetic coupling at the interface and stands as a model system to realize fascinating magnetic phenomena in layer-by-layer hetero-epitaxial oxide films.

Anti-proteolytic capacity and bonding durability of proanthocyanidin-biomodified demineralized dentin matrix.

Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin (PA) for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin-dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.