Universal adhesion using mussel foot protein inspired hydrogel with dynamic interpenetration for topological entanglement.

Achieving adhesion of hydrogels to universal materials with desirable strength remains a challenge despite emerging application of hydrogels. Herein we present a mussel foot protein (Mfp) inspired polyelectrolyte hydrogel of poly(ethylenimine)/poly(acrylic acid)-dopamine (PEI/PAADA) developed for universal tough adhesion. The highly-concentrated electrostatic and hydrogen-bonding interactions in PEI/PAADA hydrogel resulted in a tensile strength, strain at break, and toughness of 0.297 MPa, 2784 % and 5.440 MJ m-3, respectively. Moreover, the hydrogel can heal itself from physical damages, even can be recycled after totally dried via rehydration because of the high flexibility and reversibility of its dynamic bonds. Combining the strategies of topological stitching and direct bonding, Mfp-derived catechol and PEI/PAA backbone in PEI/PAADA corporately facilitated robust adhesion of universal materials with shear strength of up to 4.4 MPa and peeling strength of 870 J m-2, which is over 10 times greater than that of commercial fibrin gel. The adhesive also exhibited self-healing capability for at least 5 cycles, good stability in 1 M NaCl solution and characteristic debonding catalyzed by calcium. Moreover, in vitro cell behavior and in vivo wound healing assays suggested the potential of PEI/PAADA as wound dressing.

Overcoming the Dilemma of In Vivo Stable Adhesion and Sustained Degradation by the Molecular Design of Polyurethane Adhesives for Bone Fracture Repair.

Bone adhesive is a promising candidate to revolutionize the clinical treatment of bone repairs. However, several drawbacks have limited its further clinical application, such as unreliable wet adhesive performance leading to fixation failure and poor biodegradability inhibiting bone tissue growth. By incorporating catechol groups and disulfide bonds into polyurethane (PU) molecules, an injectable and porous PU adhesive is developed with both superior wet adhesion and biodegradability to facilitate the reduction and fixation of comminuted fractures and the subsequent regeneration of bone tissue. The bone adhesive can be cured within a reasonable time acceptable to a surgeon, and then the wet bone adhesive strength is near 1.30 MPa in 1 h. Finally, the wet adhesive strength to the cortical bone will achieve about 1.70 MPa, which is also five times more than nonresorbable poly(methyl methacrylate) bone cement. Besides, the cell culture experiments also indicate that the adhesives show excellent biocompatibility and osteogenic ability in vitro. Especially, it can degrade in vivo gradually and promote fracture healing in the rabbit iliac fracture model. These results demonstrate that this ingenious bone adhesive exhibits great potential in the treatment of comminuted fractures, providing fresh insights into the development of clinically applicable bone adhesives.

Mechanically Reinforced and Injectable Universal Adhesive Based on a PEI-PAA/Alg Dual-Network Hydrogel Designed by Topological Entanglement and Catechol Chemistry.

Universal adhesion of hydrogels to diverse materials is essential to their extensive applications. Unfortunately, tough adhesion of wet surfaces remains an urgent challenge so far, requiring robust cohesion strength for effective stress dissipation. In this work, a dual-network hydrogel polyethylenimine-poly(acrylic acid)/alginate (PEI-PAA/Alg) with excellent mechanical strength is realized via PEI-PAA complex and calcium alginate coordination for universal adhesion by the synergistic effort of topological entanglement and catechol chemistry. The dual networks of PEI-PAA/Alg provide mechanically reinforced cohesion strength, which is sufficient for energy dissipation during adhesion with universal materials. After the integration of mussel-inspired dopamine into PAA or Alg, the adhesive demonstrates further improved adhesion performance with a solid adherend and capability to bond cancellous bones. Notably, the dopamine-modified adhesive exhibits better instant adhesion and reversibility with wet surfaces compared with commercial fibrin. Adhesion interfaces are investigated by SEM and micro-FTIR to verify the effectiveness of strategies of topological entanglement. Furthermore, the adhesive also possesses great injectability, stability, tissue adhesion, and biocompatibility. In vivo wound healing and histological analysis indicate that the hydrogel can promote wound closure, epidermis regeneration, and tissue refunctionalization, implying its potential application for bioadhesive and wound dressing.

Ultrafast Early Warning of Heart Attacks through Plasmon-Enhanced Raman Spectroscopy using Collapsible Nanofingers and Machine Learning.

As the leading cause of death, heart attacks result in millions of deaths annually, with no end in sight. Early intervention is the only strategy for rescuing lives threatened by heart disease. However, the detection time of the fastest heart-attack detection system is >15 min, which is too long considering the rapid passage of life. In this study, a machine learning (ML)-driven system with a simple process, low-cost, short detection time (only 10 s), and high precision is developed. By utilizing a functionalized nanofinger structure, even a trace amount of biomarker leaked before a heart attack can be captured. Additionally, enhanced Raman profiles are constructed for predictive analytics. Five ML models are developed to harness the useful characteristics of each Raman spectrum and provide early warnings of heart attacks with >98% accuracy. Through the strategic combination of nanofingers and ML algorithms, the proposed warning system accurately provides alerts on silent heart-attack attempts seconds ahead of actual attacks.

Physiologically Based Absorption Modelling to Explore the Formulation and Gastric pH Changes on the Pharmacokinetics of Acalabrutinib.

Acalabrutinib, a selective Bruton's tyrosine kinase inhibitor, is a biopharmaceutics classification system class II drug. The aim of this study was to develop a physiologically based pharmacokinetic (PBPK) model to mechanistically describe absorption of immediate release capsule formulation of acalabrutinib in humans. Integration of in vitro biorelevant measurements, dissolution studies and in silico modelling provided clinically relevant inputs for the mechanistic absorption PBPK model. The batch specific dissolution data were integrated in two ways, by fitting a diffusion layer model scalar to the drug product dissolution with integration of drug substance laser diffraction particle size data, or by fitting a product particle size distribution to the dissolution data. The latter method proved more robust and biopredictive. In both cases, the drug surface solubility was well predicted by the Simcyp simulator. The model using the product particle size distribution (P-PSD) for each clinical batch adequately captured the PK profiles of acalabrutinib and its active metabolite. Average fold errors were 0.89 for both Cmax and AUC, suggesting good agreement between predicted and observed PK values. The model also accurately predicted pH-dependent drug-drug interactions between omeprazole and acalabrutinib, which was similar across all clinical formulations. The model predicted acalabrutinib geometric mean AUC ratios (with omeprazole vs acalabrutinib alone) were 0.51 and 0.68 for 2 batches of formulations, which are close to observed values of 0.43 and 0.51~0.63, respectively. The mechanistic absorption PBPK model could be potentially used for future applications such as optimizing formulations or predicting the PK for different batches of the drug product.

Hot Electron-Driven Photocatalysis Using Sub-5 nm Gap Plasmonic Nanofinger Arrays.

Semiconductor photocatalysis has received increasing attention because of its potential to address problems related to the energy crisis and environmental issues. However, conventional semiconductor photocatalysts, such as TiO2 and ZnO, can only be activated by ultraviolet light due to their wide band gap. To extend the light absorption into the visible range, the localized surface plasmon resonance (LSPR) effect of noble metal nanoparticles (NPs) has been widely used. Noble metal NPs can couple incident visible light energy to strong LSPR, and the nonradiative decay of LSPR generates nonthermal hot carriers that can be injected into adjacent semiconductor material to enhance its photocatalytic activity. Here we demonstrate that nanoimprint-defined gap plasmonic nanofinger arrays can function as visible light-driven plasmonic photocatalysts. The sub-5 nm gaps between pairs of collapsed nanofingers can support ultra-strong plasmon resonance and thus boost the population of hot carriers. The semiconductor material is exactly placed at the hot spots, providing an efficient pathway for hot carrier injection from plasmonic metal to catalytic materials. This nanostructure thus exhibits high plasmon-enhanced photocatalytic activity under visible light. The hot carrier injection mechanism of this platform was systematically investigated. The plasmonic enhancement factor was calculated using the finite-difference time-domain (FDTD) method and was consistent with the measured improvement of the photocatalytic activity. This platform, benefiting from the precise controllable geometry, provides a deeper understanding of the mechanism of plasmonic photocatalysis.

Acalabrutinib CYP3A-mediated drug-drug interactions: Clinical evaluations and physiologically based pharmacokinetic modelling to inform dose adjustment strategy.

AIMS: Clinical drug interaction studies with itraconazole and rifampicin have demonstrated that acalabrutinib is a sensitive substrate of CYP3A. A physiologically based pharmacokinetic (PBPK) model was developed based on the data of these studies. One of the active CYP3A metabolites, ACP-5862, was identified but never studied in a drug interaction scenario. This study aims to evaluate both parent and metabolite exposure change with coadministration of moderate CYP3A inhibitors and its impact on safety and efficacy. METHODS: In an open label, randomized, 2-period study, we investigated the effect of coadministration of fluconazole or isavuconazole on the pharmacokinetics of acalabrutinib. Bruton tyrosine kinase receptor occupancy and safety were compared between different treatments. Experimental data were compared to PBPK simulation results. RESULTS: Least square means of acalabrutinib maximum plasma concentration and area under the curve increased 1.37 (1.14-1.64) and 1.60 (1.45-1.77)-fold in the presence of isavuconazole and 1.48 (1.10-1.98) and 2.16 (1.94-2.40)-fold in the presence of fluconazole, respectively. For ACP-5862, these values are 0.72 (0.63-0.82) and 0.91 (0.86-0.97) fold for isavuconazole and 0.65 (0.49-0.87) and 0.95 (0.91-0.99) fold for fluconazole coadministration. The PBPK model was able to recover acalabrutinib and ACP-5862 PK profiles in the study. Bruton tyrosine kinase receptor occupancy change was minimal in the presence of isavuconazole. There were no deaths, serious adverse events (AEs), or subject discontinuation due to AEs in this study. Only mild (Grade 1) AEs were reported during the study, by 17% of the study population. CONCLUSION: Our results demonstrate the impact of fluconazole and isavuconazole on the pharmacokinetics of acalabrutinib and ACP-5862, and suggest that no dose adjustment is needed for concomitant administration with moderate CYP3A inhibitors. the current PBPK model can be used to propose dose adjustment for drug interactions via CYP3A.

The Craft of Color and the Chemistry of Dyes: Textile Technology in the Ryukyu Kingdom, 1700-1900.

This article explores the little-known history of bingata, a textile technology of resist dyeing developed in the Ryukyu Islands (modern-day Okinawa, Japan) during the sixteenth to eighteenth centuries and later, promoted as traditional folk craft under Japanese colonialism. Located at the center of tributary and trading networks linking Northeast and Southeast Asia and, after 1600, Europe, the Ryukyus were an integral part of the early modern world. Tracing the circulation of Prussian blue from Europe to Asia, this article shows how shared materials and techniques afforded by trade networks linked the craft work of Ryukyu craftsmen to the experimental science of European dyer-chemists. In doing so, this article challenges longstanding binaries that oppose West and non-West, science and craft knowledge, and traditional folk crafts and modern technology. It argues that the reciprocal relationship between materials and techniques underpinned the knowledge-making practices of both Ryukyu dyers and European dyer-chemists.

Mechanistic physiology-based pharmacokinetic modeling to elucidate vincristine-induced peripheral neuropathy following treatment with novel kinase inhibitors.

PURPOSE: Limited information is available regarding the drug-drug interaction (DDI) potential of molecular targeted agents and rituximab plus cyclophosphamide, doxorubicin (hydroxydaunorubicin), vincristine (Oncovin), and prednisone (R-CHOP) therapy. The addition of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib to R-CHOP therapy results in increased toxicity versus R-CHOP alone, including higher incidence of peripheral neuropathy. Vincristine is a substrate of P-glycoprotein (P-gp, ABCB1); drugs that inhibit P-gp could potentially cause increased toxicity when co-administered with vincristine through DDI. While the combination of the BTK inhibitor acalabrutinib and R-CHOP is being explored clinically, the DDI potential between these therapies is unknown. METHODS: A human mechanistic physiology-based pharmacokinetic (PBPK) model of vincristine following intravenous dosing was developed to predict potential DDI interactions with combination therapy. In vitro absorption, distribution, metabolism, and excretion and in vivo clinical PK parameters informed PBPK model development, which was verified by comparing simulated vincristine concentrations with observed clinical data. RESULTS: While simulations suggested no DDI between vincristine and ibrutinib or acalabrutinib in plasma, simulated vincristine exposure in muscle tissue was increased in the presence of ibrutinib but not acalabrutinib. Extrapolation of the vincristine mechanistic PBPK model to other P-gp substrates further suggested DDI risk when ibrutinib (area under the concentration-time curve [AUC] ratio: 1.8), but not acalabrutinib (AUC ratio: 0.92), was given orally with venetoclax or digoxin. CONCLUSION: Overall, these data suggest low DDI risk between acalabrutinib and P-gp substrates with negligible increase in the potential risk of vincristine-induced peripheral neuropathy when acalabrutinib is added to R-CHOP therapy.

Improving the Translation of Organic Anion Transporting Polypeptide Substrates using HEK293 Cell Data in the Presence and Absence of Human Plasma via Physiologically Based Pharmacokinetic Modeling.

Accurately predicting the pharmacokinetics of compounds that are transporter substrates has been notoriously challenging using traditional in vitro systems and physiologically based pharmacokinetic (PBPK) modeling. The objective of this study was to use PBPK modeling to understand the translational accuracy of data generated with human embryonic kidney 293 (HEK293) cells overexpressing the hepatic uptake transporters organic anion transporting polypeptide (OATP) 1B1/3 with and without plasma while accounting for transporter expression. Models of four OATP substrates, two with low protein binding (pravastatin and rosuvastatin) and two with high protein binding (repaglinide and pitavastatin) were explored, and the OATP in vitro data generated in plasma incubations were used for a plasma model, and in buffer incubations for a buffer model. The pharmacokinetic parameters and concentration-time profiles of pravastatin and rosuvastatin were similar and well predicted (within 2-fold of observed values) using the plasma and buffer models without needing an empirical scaling factor, whereas the dispositions of the highly protein bound repaglinide and pitavastatin were more accurately simulated with the plasma models than the buffer models. This work suggests that data from HEK293 overexpressing transporter cells corrected for transporter expression represent a valid approach to improve bottom-up PBPK modeling for highly protein bound OATP substrates with plasma incubations and low protein binding OATP substrates with or without plasma incubations. SIGNIFICANCE STATEMENT: This work demonstrates the bottom-up approach of using in vitro data directly without employing empirical scaling factors to predict the intravenous pharmacokinetic (PK) profiles reasonably well for four organic anion transporting polypeptide (OATP) substrates. Based on these results, using HEK293 overexpressing cells, examining the impact of plasma for highly bound compounds, and incorporating transporter quantitation for the lot in which the in vitro data were generated represents a valid approach to achieve more accurate prospective PK predictions for OATP substrates.

A Tantalum Disulfide Charge-Density-Wave Stochastic Artificial Neuron for Emulating Neural Statistical Properties.

Artificial neuronal devices that functionally resemble biological neurons are important toward realizing advanced brain emulation and for building bioinspired electronic systems. In this Communication, the stochastic behaviors of a neuronal oscillator based on the charge-density-wave (CDW) phase transition of a 1T-TaS2 thin film are reported, and the capability of this neuronal oscillator to generate spike trains with statistical features closely matching those of biological neurons is demonstrated. The stochastic behaviors of the neuronal device result from the melt-quench-induced reconfiguration of CDW domains during each oscillation cycle. Owing to the stochasticity, numerous key features of the Hodgkin-Huxley description of neurons can be realized in this compact two-terminal neuronal oscillator. A statistical analysis of the spike train generated by the artificial neuron indicates that it resembles the neurons in the superior olivary complex of a mammalian nervous system, in terms of its interspike interval distribution, the time-correlation of spiking behavior, and its response to acoustic stimuli.

Ocular phenotypes in a mouse model of impaired glucocerebrosidase activity.

Mutations in the GBA1 gene encoding glucocerebrosidase (GCase) are linked to Gaucher (GD) and Parkinson's Disease (PD). Since some GD and PD patients develop ocular phenotypes, we determined whether ocular phenotypes might result from impaired GCase activity and the corresponding accumulation of glucosylceramide (GluCer) and glucosylsphingosine (GluSph) in the Gba1D409V/D409V knock-in (Gba KI/KI; "KI") mouse. Gba KI mice developed age-dependent pupil dilation deficits to an anti-muscarinic agent; histologically, the iris covered the anterior part of the lens with adhesions between the iris and the anterior surface of the lens (posterior synechia). This may prevent pupil dilation in general, beyond an un-responsiveness of the iris to anti-muscarinics. Gba KI mice displayed atrophy and pigment dispersion of the iris, and occlusion of the iridocorneal angle by pigment-laden cells, reminiscent of secondary open angle glaucoma. Gba KI mice showed progressive thinning of the retina consistent with retinal degeneration. GluSph levels were increased in the anterior and posterior segments of the eye, suggesting that accumulation of lipids in the eye may contribute to degeneration in this compartment. We conclude that the Gba KI model provides robust and reproducible eye phenotypes which may be used to test for efficacy and establish biomarkers for GBA1-related therapies.

A memristor-based hybrid analog-digital computing platform for mobile robotics.

Algorithms for mobile robotic systems are generally implemented on purely digital computing platforms. Developing alternative computational platforms may lead to more energy-efficient and responsive mobile robotics. Here, we report a hybrid analog-digital computing platform enabled by memristors on a mobile inverted pendulum robot. Our mobile robotic system can tune the conductance states of memristors adaptively using a model-free optimization method to achieve optimal control performance. We implement sensor fusion and the motion control algorithms on our hybrid analog-digital computing platform and demonstrate more than one order of magnitude enhancement of speed and energy efficiency over traditional digital platforms.

Probing the Mechanisms of Strong Fluorescence Enhancement in Plasmonic Nanogaps with Sub-nanometer Precision.

Plasmon-enhanced fluorescence is demonstrated in the vicinity of metal surfaces due to strong local field enhancement. Meanwhile, fluorescence quenching is observed as the spacing between fluorophore molecules and the adjacent metal is reduced below a threshold of a few nanometers. Here, we introduce a technology, placing the fluorophore molecules in plasmonic hotspots between pairs of collapsible nanofingers with tunable gap sizes at sub-nanometer precision. Optimal gap sizes with maximum plasmon enhanced fluorescence are experimentally identified for different dielectric spacer materials. The ultrastrong local field enhancement enables simultaneous detection and characterization of sharp Raman fingerprints in the fluorescence spectra. This platform thus enables in situ monitoring of competing excitation enhancement and emission quenching processes. We systematically investigate the mechanisms behind fluorescence quenching. A quantum mechanical model is developed which explains the experimental data and will guide the future design of plasmon enhanced spectroscopy applications.

Quantitation of DNA by nuclease P1 digestion and UPLC-MS/MS to assess binding efficiency of pyrrolobenzodiazepine.

Accurate DNA quantitation is a prerequisite in many biomedical and pharmaceutical studies. Here we established a new DNA quantitation method by nuclease P1 digestion and UPLC-MS/MS analysis. DNA fragments can be efficiently hydrolyzed to single deoxyribonucleotides by nuclease P1 in a short time. The decent stabilities of all the four deoxyribonucleotides were confirmed under different conditions. Deoxyadenosine monophosphate (dAMP) was selected as the surrogate for DNA quantitation because dAMP showed the highest sensitivity among the four deoxyribonucleotides in the UPLC-MS/MS analysis. The linear range in DNA quantitation by this method is 1.2-5000 ng/mL. In the validation, the inter-day and intra-day accuracies were within 90%-110%, and the inter-day and intra-day precision were acceptable (RSD < 10%). The validated method was successfully applied to quantitate DNA isolated from tumors and organs of a mouse xenograft model. Compared to the quantitation methods using UV absorbance, the reported method provides an enhanced sensitivity, and it allows for the accurate quantitation of isolated DNA with contamination of RNA and ribonucleotide.

Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling.

The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination of palladium and a chiral phosphoric acid was investigated by a combined experimental and statistical modeling approach. Experiments to probe nonlinear effects, the reactivity of deuterium-labeled substrates, and control experiments revealed that nucleophilic attack to the π-allylpalladium intermediate is the enantio-determining step, in which the chiral phosphate anion is involved in stereoinduction. Using multivariable linear regression analysis, we determined that multiple noncovalent interactions with the chiral environment of the phosphate anion are integral to enantiocontrol in the transition state. The synthetic protocol to form chiral pyrrolidines was further applied to the asymmetric construction of C-O bonds at fully substituted carbon centers in the synthesis of chiral 2,2-disubstituted benzomorpholines.

GDC-0810 Pharmacokinetics and Transporter-Mediated Drug Interaction Evaluation with an Endogenous Biomarker in the First-in-Human, Dose Escalation Study.

GDC-0810 (Cheeti et al., 2018) is an orally bioavailable, selective estrogen receptor (ER) degrader developed to treat ER-positive breast cancer. A first-in-human (FIH) dose escalation phase I study (n = 41) was conducted to characterize the pharmacokinetics (PK) of GDC-0810 and its two major metabolites. GDC-0810 demonstrated linear PK from 100 to 600 mg given once daily. The mean terminal half-life following a single 600 mg dose was approximately 8 hours. Since GDC-0810 is a potent in vitro inhibitor of organic anion transporting polypeptide (OATP) 1B1/3, the kinetic profile of coproporphyrin I (CPI), a promising endogenous biomarker for OATP1B1/3, was analyzed retrospectively in a subset of the plasma samples collected in the same FIH study. CPI exhibited a GDC-0810 dose-dependent increase, suggesting in vivo inhibition of OATP1B transporters. To quantitatively predict the magnitude of OATP1B-mediated drug-drug interactions (DDIs) with pravastatin (a known OATP1B substrate), the in vivo unbound inhibition constant was first estimated using a one-compartment model, and then incorporated to a physiologically based pharmacokinetic model. The model showed some underestimation of the magnitude of the DDI when compared with a clinical DDI study result, while prediction had a relatively large uncertainty due to the small effect size, limited sample size, and variability in CPI kinetics. In conclusion, this study characterized the pharmacokinetic profiles of GDC-0810 in breast cancer patients and demonstrated the utility of CPI in detecting OATP1B-mediated DDIs of a new molecular entity as early as FIH study. SIGNIFICANCE STATEMENT: Endogenous biomarkers of transporters have recently been shown to be promising tools in evaluating the risk of clinical transporter-mediated DDIs. This is the first study to report a pharmacokinetic interaction between an investigational molecule and a transporter biomarker in a first-in-human study. The observed interaction and model-based analysis and the prediction provide important insights on the novel approach to quantitatively predict transporter-mediated DDIs as early as FIH studies in the clinical development.

Needham, Matter, Form, and Us.

Joseph Needham offered a vision of history that united his understanding of the physical world with his interpretation of social process, in which the material, social, and ideal realms were reciprocally constituted. This essay explores Needham's ideas about matter and form to show how he developed a systematic theory of materialism in his early writings on science and social change. Shifting the ground of discourse in Needham's project from "science" to "materialism," the essay brings him into conversation with new materialists to reflect on the ongoing challenges in theorizing the relationship between social and material phenomena. Calling into question an all-encompassing materiality that sacrifices the role of determinate structures and histories in the production of the world, the essay asks: How can we formulate a framework of material/-ity/-ism that does not dispense with or occlude the already embedded politics of culture, social relations of production, and historical contingency?

A Novel Depurination Methodology to Assess DNA Alkylation of Chloro-Bis-Seco-Cyclopropylbenzoindoles Allowed for Comparison of Minor-Groove Reactivity.

Duocarmycins [including cyclopropyl pyrroloindole (CPI) or cyclopropyl benzoindole (CBI)] are a class of DNA minor-groove alkylators and seco-CPI/CBIs are synthetic pro-forms that can spirocyclize to CPI/CBI. Bis-CPI/CBIs are potential drug candidates because of their enhanced cytotoxicity from DNA crosslinking, but it is difficult to analyze them for structure-activity correlation because of their DNA reactivity. To study their DNA alkylation, neutral thermal hydrolysis has been frequently applied to process depurination. However, unwanted side reactions under this condition have been reported, which could lead to poor correlation of DNA alkylation data with efficacy results, especially for bis-CPI/CBIs. In this study, an acidic depurination method was developed and applied for analysis of DNA alkylation and shown to be an easier and milder method than the traditional neutral thermal hydrolysis. DNA alkylation and stability of three bis-seco-CBIs were characterized in comparison with two mono-seco-CPIs. The results suggested that: 1) The acidic depurination method was capable of capturing a more representative population, sometimes a different population, of DNA adducts as they existed on DNA compared with the heat depurination method. 2) Di-adenine adducts were captured as expected for the CBI dimers, although the major type of adduct was still mono-adenine adducts. 3) The rate of DNA alkylation, DNA adduct profile, and relative amounts of di-adduct versus mono-adduct were significantly affected by the size, and possibly lipophilicity, of the nonalkylating part of the molecules. 4) Spirocyclization and amide hydrolysis represented two major pathways of degradation. Overall, by applying acidic depurination analyses, this study has illustrated DNA adduct characteristics of novel bis-seco-CBIs with dominating mono-alkylation and provides an alternative method for evaluating DNA minor-groove alkylators. These findings provide an effective analytical tool to evaluate DNA alkylators and to study the DNA alkylation that is a disposition mechanism of these compounds.