ACS Central Science最新文献

This outlook explores how two different molecular imaging approaches might be combined to gain insight into dynamic, subcellular metabolic processes. Specifically, we discuss how matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) and stimulated Raman scattering (SRS) microscopy, which have significantly pushed the boundaries of imaging metabolic and metabolomic analyses in their own right, could be combined to create comprehensive molecular images. We first briefly summarize the recent advances for each technique. We then explore how one might overcome the inherent limitations of each individual method, by envisioning orthogonal and interchangeable workflows. Additionally, we delve into the potential benefits of adopting a complementary approach that combines both MSI and SRS spectro-microscopy for informing on specific chemical structures through functional-group-specific targets. Ultimately, by integrating the strengths of both imaging modalities, researchers can achieve a more comprehensive understanding of biological and chemical systems, enabling precise metabolic investigations. This synergistic approach holds substantial promise to expand our toolkit for studying metabolites in complex environments.

Integrating SRS microscopy and MALDI MSI offers a powerful imaging approach to investigate metabolites at the subcellular level in biological systems.

Innovating the design of chimeric antigen receptors (CARs) beyond conventional structures would be necessary to address the challenges of efficacy, safety, and applicability in T cell-based cancer therapy, whereas excessive genetic modification might complicate CAR design and manufacturing, and increase gene editing risks. In this work, we used aptamers as the antigen-recognition unit to develop a nongenetic CAR engineering strategy for programming the antitumor activity and specificity of CAR T cells. Our results demonstrated that aptamer-functionalized CAR (Apt-CAR) T cells could be directly activated by recognizing target antigens on cancer cells, and then impart a cytotoxic effect for cancer elimination in vitro and in vivo. The designable antigen recognition capability of Apt-CAR T cells allows for easy modulation of their efficacy and specificity. Additionally, multiple features, e.g., tunable antigen-binding avidity and the tumor microenvironment responsiveness, could be readily integrated into Apt-CAR design without T cell re-engineering, offering a new paradigm for developing adaptable immunotherapeutics.

We used aptamers as the antigen-targeting unit and developed a nongenetic CAR reprograming platform for customized modulation of T cell-based cancer immunotherapy. Based on the excellent programmability of DNA nanotechnology and the designable recognition capability of aptamers, the cancer targeting avidity and specificity of aptamer-functionalized CAR (Apt-CAR) T cells can be readily modulated, offering a new paradigm for the development of modulable immunotherapeutics.

Proton exchange membrane water electrolysis (PEMWE) is a promising solution for the conversion and storage of fluctuating renewable energy sources. Although tremendously efficient materials have been developed, commercial PEMWE products still cannot fulfill industrial demands regarding efficiency and stability. In this work, we demonstrate that the stress distribution, a purely mechanical parameter in electrolyzer assembly, plays a critical role in overall efficiency and stability. The conventional cell structure, which usually adopts a serpentine flow channel (S-FC) to deliver and distribute reactants and products, resulted in highly uneven stress distribution. Consequently, the anode catalyst layer (ACL) under the high stress region was severely deformed, whereas the low stress region was not as active due to poor electrical contact. To address these issues, we proposed a Ti mesh flow channel (TM-FC) with gradient pores to reduce the stress inhomogeneity. Consequently, the ACL with TM-FC exhibited 27 mV lower voltage initially and an 8-fold reduction in voltage degradation rate compared to that with S-FC at 2.0 A/cm². Additionally, the applicability of the TM-FC was demonstrated in cross-scale electrolyzers up to 100 kW, showing a voltage increase of only 20 mV (accounting for less than 2% of overall voltage) after three orders of magnitude scaleup.

A homogeneously distributed stress distribution in a gradient titanium mesh flow channel significantly enhances performance and stability of PEM water electrolysis compared to a serpentine flow channel.

Degenerative diseases are closely related to the changes of protein conformation beyond the steady state. The development of feasible tools for quantitative detection of changes in the cellular environment is crucial for investigating the process of protein conformational variations. Here, we have developed a near-infrared AIE probe based on the rhodamine fluorophore, which exhibits dual responses of fluorescence intensity and lifetime to local viscosity changes. Notably, computational analysis reveals that NRhFluors fluorescence activation is due to inhibition of the RACI mechanism in viscous environment. In the chemical regulation of rhodamine fluorophores, we found that variations of electron density distribution can effectively regulate CI states and achieve fluorescence sensitivity of NRhFluors. In addition, combined with the AggTag method, the lifetime of probe A9-Halo exhibits a positive correlation with viscosity changes. This analytical capacity allows us to quantitatively monitor protein conformational changes using fluorescence lifetime imaging (FLIM) and demonstrate that mitochondrial dysfunction leads to reduced protein expression in HEK293 cells. In summary, this work developed a set of near-infrared AIE probes activated by the RACI mechanism, which can quantitatively detect cell viscosity and protein aggregation formation, providing a versatile tool for exploring disease-related biological processes and therapeutic approaches.

A series of near-infrared AIE probes activated by the RACI mechanism based on rhodamine fluorophores, which can quantitatively reveal viscosity changes in protein aggregate under mitochondrial damage.

The biosynthetic capability of the bacterial ribosome motivates efforts to understand and harness sequence-optimized versions for synthetic biology. However, functional differences between natively occurring ribosomal RNA (rRNA) operon sequences remain poorly characterized. Here, we use an in vitro ribosome synthesis and translation platform to measure protein production capabilities of ribosomes derived from all unique combinations of 16S and 23S rRNAs from seven distinct Escherichia coli rRNA operon sequences. We observe that polymorphisms that distinguish native E. coli rRNA operons lead to significant functional changes in the resulting ribosomes, ranging from negligible or low gene expression to matching the protein production activity of the standard rRNA operon B sequence. We go on to generate strains expressing single rRNA operons and show that not only do some purified in vivo expressed homogeneous ribosome pools outperform the wild-type, heterogeneous ribosome pool but also that a crude cell lysate made from the strain expressing only operon A ribosomes shows significant yield increases for a panel of medically and industrially relevant proteins. We anticipate that ribosome pool engineering can be applied as a tool to increase yields across many protein biomanufacturing systems, as well as improve basic understanding of ribosome heterogeneity and evolution.

Unique rRNA operons existing in the Escherichia coli genome yield functionally distinct ribosomes with varying recombinant protein synthesis capabilities in cell-free systems.

A metal-free organic cathode material is described that has high energy storage capacity, can be charged quickly, and has excellent cycle life.

Immunosuppressants are clinically approved drugs to treat the potential rejection of transplanted organs and require frequent monitoring due to their narrow therapeutic window. Immunophilins are small proteins that bind immunosuppressants with high affinity, yet there are no examples of fluorogenic immunophilins and their potential application as optical biosensors for immunosuppressive drugs in clinical biosamples. In the present work, we designed novel diazonium BODIPY salts for the site-specific labeling of tyrosine residues in peptides via solid-phase synthesis as well as for late-stage functionalization of whole recombinant proteins. After the optimization of a straightforward one-step labeling procedure for immunophilins PPIA and FKBP12, we demonstrated the application of a fluorogenic analogue of FKBP12 for the selective detection of the immunosuppressant drug tacrolimus, including experiments in urine samples from patients with functioning renal transplants. This chemical methodology opens new avenues to rationally design wash-free immunophilin-based biosensors for rapid therapeutic drug monitoring.

We describe diazonium BODIPYs for the straightforward labeling of Tyr-containing peptides and whole proteins and the first fluorogenic analogue of immunophilin FKBP12 for the wash-free detection of tacrolimus in clinical biosamples.

Efficient prioritization of bioactive compounds from high throughput screening campaigns is a fundamental challenge for accelerating drug development efforts. In this study, we present the first data-driven approach to simultaneously detect assay interferents and prioritize true bioactive compounds. By analyzing the learning dynamics during training of a gradient boosting model on noisy high throughput screening data using a novel formulation of sample influence, we are able to distinguish between compounds exhibiting the desired biological response and those producing assay artifacts. Therefore, our method enables false positive and true positive detection without relying on prior screens or assay interference mechanisms, making it applicable to any high throughput screening campaign. We demonstrate that our approach consistently excludes assay interferents with different mechanisms and prioritizes biologically relevant compounds more efficiently than all tested baselines, including a retrospective case study simulating its use in a real drug discovery campaign. Finally, our tool is extremely computationally efficient, requiring less than 30 s per assay on low-resource hardware. As such, our findings show that our method is an ideal addition to existing false positive detection tools and can be used to guide further pharmacological optimization after high throughput screening campaigns.

Minimum variance sampling analysis (MVS-A) is a fast machine-learning approach enabling the identification of both true bioactive compounds and false positives in high throughput screening data.

In this issue of ACS Central Science, Jeremy Baskin and his team showcase their latest feat of phospholipase D (PLD) engineering, by adding blue light-dependent activation to their growing toolbox of PLD-based membrane editing techniques.

We have discovered that hard, electrical conductors (e.g., metals or graphite) can be adhered to soft, aqueous materials (e.g., hydrogels, fruit, or animal tissue) without the use of an adhesive. The adhesion is induced by a low DC electric field. As an example, when 5 V DC is applied to graphite slabs spanning a tall cylindrical gel of acrylamide (AAm), a strong adhesion develops between the anode (+) and the gel in about 3 min. This adhesion endures after the field is removed, and we term it as hard–soft electroadhesion or EA^[HS]. Depending on the material, adhesion occurs at the anode (+), cathode (−), or both electrodes. In many cases, EA^[HS] can be reversed by reapplying the field with reversed polarity. Adhesion via EA^[HS] to AAm gels follows the electrochemical series: e.g., it occurs with copper, lead, and tin but not nickel, iron, or zinc. We show that EA^[HS] arises via electrochemical reactions that generate chemical bonds between the electrode and the polymers in the gel. EA^[HS] can create new hybrid materials, thus enabling applications in robotics, energy storage, and biomedical implants. Interestingly, EA^[HS] can even be achieved underwater, where typical adhesives cannot be used.

A DC electric field can be used to stick metals or graphite to soft materials including gels, animal tissues, fruits, and vegetables. Such electroadhesion is reversible and even works underwater.