ACS Applied Nano Materials最新文献

The coffee-ring effect is an eye-catching circle originating from a material-suspended liquid droplet at a solid substrate after liquid evaporation, but the low speediness has restricted practical applications. When nanomaterial aqueous solutions are dropped onto porous nitrocellulose (NC), the liquid is immediately absorbed through the porous tunnels of paper fibers, and nanomaterials are rapidly enriched on the contact lines between droplets and membranes. We called this ultrafast variant of the coffee ring effect the “tunneling coffee ring” (TCR). When nanomaterial sizes are smaller than that of pores, a larger-diameter ring of nanomaterials quickly materializes. The real-time particle size-dependent TCRs and liquid diffusion rings exhibit a dual-ring pattern on the NC membrane. The tunneling speed of the capillary effect is so fast that the pattern appears within seconds. We apply the TCR effect as a size-surface affinity-particle/fluid separation sensor for bacteria. Dextran-modified Au and MoS₂ nanostructures are proposed to be antibody-free microbe kits. Our TCR effect is used to distinguish between particles of different sizes and affinities, which are highly relevant in complicated systems without electricity and equipment in resource-poor settings.

Bispecific antibodies (bsAbs) and multispecific antibodies (msAbs) represent a promising frontier in therapeutic antibody development, offering unique capabilities not achievable with traditional monoclonal antibodies. Despite their potential, significant challenges remain due to their increased molecular complexity. One prominent challenge is the correct assembly of light and heavy chains, as improper pairing leads to mispaired or incompletely assembled species that lack therapeutic efficacy and possess undesired properties, impairing the developability, manufacturability, and safety. There is a critical need for rapid, sensitive analytical tools to monitor and control these undesired species and ensure the quality assessment of bsAbs and msAbs. To address this need, we present a novel high-throughput, format-agnostic intact mass workflow that significantly enhances the efficiency of detecting and quantifying biotherapeutic products and related impurities. This workflow integrates automated sample preparation, novel high-resolution rapid mass detection powered by SampleStream-MS, and an advanced data analysis pipeline. It offers increased throughput and data quality while substantially reducing analysis turnover time and labor. This was demonstrated in a pilot program where ∼800 multispecific antibodies were processed in 10 working days. The article details the evaluation and validation of our method, demonstrating its repeatability and intermediate precision in terms of measurement accuracy and relative quantification of various product-related species. We underscore the transformative potential of this end-to-end high-throughput workflow in expediting bispecific and multispecific antibody discovery, optimizing production processes, and ensuring high-quality development and manufacturing for therapeutic antibodies.

Infrared (IR) spectroscopy is a powerful analytical technique used to identify and quantify different components within a sample. However, spectral interference from fluctuating concentrations of water vapor and CO₂ in the measurement chamber can significantly impede the extraction of quantitative information. These temporal fluctuations cause absorption variations that interfere with the sample’s spectrum, making accurate analysis challenging. While several techniques to overcome this problem exist in the literature, many are time-consuming or ineffective. We present a simple method utilizing just two sample spectra taken sequentially. The difference of these spectra, multiplied by a scaling factor, determined by minimization of the point-to-point spectral length, provides a correction spectrum. Subtracting this from the spectrum to be corrected results in a fully corrected spectrum. We demonstrate the effectiveness of this method via the improved ability to determine analyte concentration from corrected spectra over uncorrected spectra using a partial least square regression (PLSR) model. This technique therefore offers rapid, effective, and automated spectral correction, which is ideal for a nonexpert user in a clinical or industrial setting.

Screening a novel electrochemiluminescence (ECL) system and lowering the ECL triggering potential are essential to ECL evolution. Herein, the near-infrared (NIR) ECL system with low-triggering potential ECL was constructed with weakly reductive tert-butylamine borane as coreactant and mercaptosuccinic acid/citrate (MSA/Cit)-capped Au (MSA/Cit@AuNCs) as luminophores. Toxic-element-free and dual-ligand MSA/Cit@AuNCs were prepared via ligand exchange and utilized as a model for developing unary metal NCs-based luminophores with more enhanced ECL performance than monoligand Au nanocrystals (AuNCs), which exhibited a two hole-injected process at around 0.48 and 0.80 V, respectively. Beneficial to the intrinsic low hole-injected potential of AuNCs, MSA/Cit@AuNCs exhibited similar low-triggering ECL potential at around 0.57 V with the participation of series coreactants or not, originating from the recombination of an internal prestored electron within the conduction band (CB) and electroinjected holes at around 0.25 V. Furthermore, the enhanced low-triggering potential around 0.57 V and NIR ECL around 835 nm of MSA/Cit@AuNCs was eventually obtained with the reductive tert-butylamine borane or N₂H₄·H₂O containing a −C–N single-bond structure merely as coreactant. The low-triggering potential ECL of MSA/Cit@AuNCs/tert-butylamine borane system at 0.57 V can be harnessed to selectively determine a carcinoembryonic antigen (CEA) with one linear range spanning from 2 to 20000 fg/mL and a limit of detection of 0.33 fg/mL (S/N = 3). This study will contribute to a more comprehensive understanding of the ECL mechanism in terms of both regulating NCs and selecting coreactants.

Bees produce honey through the collection and transformation of nectar, whose botanical origin impacts the taste, nutritional value, and, therefore, the market price of the resulting honey. This phenomenon has led some to mislabel their honey so that it can be sold at a higher price. Metabolomics has been gaining popularity in food authentication, but rapid data mining algorithms are needed to facilitate the discovery of new authenticity markers. A nontargeted high-resolution liquid chromatography–mass spectrometry (HR/LC–MS) analysis of 262 monofloral honey samples, of which 50 were blueberry honey, was performed. Data mining methods were demonstrated for the discovery of binary single-markers (compound was only detected in blueberry honey), threshold single-markers (compound had the highest concentration in blueberry honey), and interval ratio-markers (the ratio of two compounds was within a unique interval in blueberry honey). A novel convolutional algorithm was developed for the discovery of interval ratio-markers, which trained 14× faster and achieved a 0.2 Matthews correlation coefficient (MCC) units higher classification score than existing open-source implementations. The convolutional algorithm also had classification performance similar to that of a brute-force search but trained 1521× faster. A pipeline for shortlisting candidate authenticity markers from the LC-MS spectra that may be suitable for chemical structure identification was also demonstrated and led to the identification of niacin as a blueberry honey threshold single-marker. This work demonstrates an end-to-end approach to mine the honey metabolome for novel authenticity markers and can readily be applied to other types of food and analytical chemistry instruments.

Escherichia coli O157:H7 (E. coli O157:H7) is a prominent pathogenic bacterium that poses serious risks to food safety and public health. Rapid and accurate detection of live E. coli O157:H7 is of great importance in food quality monitoring and clinical diagnosis. Here, we report a propidium monoazide-assisted nonamplification digital CRISPR/Cas12a assay for sensitive and rapid detection of live E. coli O157:H7. The incorporation of propidium monoazide into the method enables the selective detection of live bacteria by eliminating 98% of interference from the dead bacterial nucleic acid. Implemented on microfluidic digital chips, this method can achieve absolute quantification of nonamplified nucleic acid. The entire detection process of live bacteria can be completed within 120 min without the need for establishing a standard curve, and the sensitivity of the method reaches 1.2 × 10³ CFU/mL. The method was validated using various samples, yielding results consistent with the plate counting method (Pearson’s r = 0.9490). Consequently, this method holds significant potential for applications in fields requiring live bacterial detection.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer (BC). Thus, early detection and accurate diagnosis of this cancer are crucial for improving the survival rate of patients. Specific microRNAs (miRNAs) have been implicated in the occurrence, proliferation, and metastasis of TNBC. Addressing this need, our study developed a biosensor platform for early and accurate TNBC diagnosis by integrating electrochemiluminescence (ECL) technology with a DNA sensing strategy. Specifically, synthesized positively charged carbon dots (CDs) were used to neutralize the electrostatic repulsion between DNA strands and facilitate the assembly of DNA triangular prisms (DNA TP-CDs). Hairpins were then incorporated into the DNA TP-CDs to form the final DNA crown structure. The early TNBC biomarker, microRNA-93–3p (miR-93–3p), allowed for the binding between the DNA Crown and the DNA track on the electrode and initiated the ECL signal. Subsequently, microRNA-210 (miR-210) unlocked the DNA tripedal walker, and its movement on the DNA Crown eventually quenched the ECL signal, enabling accurate TNBC diagnosis and tumor stage assessment. Our proposed biosensor had satisfactory sensing efficiency due to the ordered DNA track and rapid-moving DNA walker. The data revealed a good linear relationship between the ECL signals and the logarithm of miRNA concentrations, with miR-93–3p having a detection limit of 31.04 aM and miR-210 having a detection limit of 7.69 aM. The biosensor also showed satisfactory performance in serum samples and cells. Taken together, this study hopes to provide ideas and applications for clinical diagnosis as well as the personalized treatment of TNBC.

Allostery is a phenomenon where the binding of a ligand at one allosteric site influences the affinity for another ligand at an active site. Different from orthosteric regulation, it allows for more precise control of biomolecular activity and enhances the stability of the molecules. Inspired by allosteric regulation of natural molecules, we present a Y-shaped allosteric DNA nanodevice, termed YssAP, that was pH-responsive and functionalized with the AS1411 aptamer for accurate fluorescence imaging of human apurinic/apyrimidinic endonuclease (APE1) activity in tumor cells. With rational design, YssAP could not be cut by APE1, and Cy5 was in the proximity of BHQ2, leading to suppressed signal emission. In contrast, since acidic pH acted as an allosteric effector, YssAP underwent a conformational change into an activated DNA probe (YdsAP) at acidic extracellular pH. After entering the tumor cell via the specific recognition of AS1411 aptamer, the overexpressed APE1 in the tumor cell cut the AP site on YdsAP. Cy5 moved far away from BHQ2, resulting in a strong signal output. Compared with the direct construction of the APE1 substrate, allosteric DNA nanodevices have more accurate imaging effects, which can be precisely adjusted by changing the switching state. We anticipate that this strategy will be applied in the screening of APE1 inhibitors and precise tumor diagnosis.

Chemical interface damping (CID) is a newly proposed plasmon damping pathway based on interfacial hot-electron transfer from metal to adsorbate molecules. However, achieving in situ tunability of CID in single gold nanorods (AuNRs) remains a considerable challenge. Here, we present the CID effect induced by benzene 1,2-dithiol (BDT) molecule adsorption on single AuNRs and the effective electrochemical tunability of CID in BDT-adsorbed AuNRs immobilized on an indium tin oxide (ITO) surface. Manipulations of the electrochemical potential alter the electron density of AuNRs, thereby influencing and tuning the localized surface plasmon resonance (LSPR) spectrum, with cathodic potential blueshifting and anodic potential redshifting. The strong adsorption of BDT on Au induced CID in single AuNRs. The potential-induced LSPR scattering spectra of BDT-adsorbed AuNRs for linear potential sweep showed a stable LSPR spectral response, irrespective of the concentrations of BDT molecules. Due to the involvement of two Au–S bonds, BDT molecules have a higher free adsorption energy and a lower desorption rate on the Au surface. This resulted in a stable LSPR spectral response for a linear electrochemical potential sweep. Furthermore, a constant anodic and cathodic potential application showed the tunability of the CID at the BDT-Au interface.

Many chiral carboxylic acids with α-amino, α-hydroxyl, and α-methyl groups are concurrently present in mammals establishing unique molecular phenotypes and multiple biological functions, especially host-microbiota symbiotic interactions. Their chirality-resolved simultaneous quantification is essential to reveal the biochemical details of physiology and pathophysiology, though challenging with their low abundances in some biological matrices and difficulty in enantiomer resolution. Here, we developed a method of the chirality-resolved metabolomics with sensitivity-enhanced quantitation via probe-promotion (Met-SeqPro) for analyzing these chiral carboxylic acids. We designed and synthesized a hydrazide-based novel chiral probe, (S)-benzoyl-proline-hydrazide (SBPH), to convert carboxylic acids into amide diastereomers to enhance their retention and chiral resolution on common C₁₈ columns. Using the d₅-SBPH-labeled enantiomers as internal standards, we then developed an optimized ultrahigh-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous quantification of 60 enantiomers of 30 chiral carboxylic acids in one run. This enantiomer-resolved method showed excellent sensitivity (LOD < 4 fmol-on-column), linearity (R² > 0.992), precision (CV < 15%), accuracy (|RE| < 20%), and recovery (80−120%) in multiple biological matrices. With the method, we then quantified 60 chiral carboxylic acids in human urine, plasma, feces, and A549 cells to define their metabolomic phenotypes. This provides basic data for human phenomics and a promising tool for investigating the mammal-microbiome symbiotic interactions.