Reducing target binding affinity improves the therapeutic index of anti-MET antibody-drug conjugate in tumor bearing animals.

Many oncology antibody-drug conjugates (ADCs) have failed to demonstrate efficacy in clinic because of dose-limiting toxicity caused by uptake into healthy tissues. We developed an approach that harnesses ADC affinity to broaden the therapeutic index (TI) using two anti-mesenchymal-epithelial transition factor (MET) monoclonal antibodies (mAbs) with high affinity (HAV) or low affinity (LAV) conjugated to monomethyl auristatin E (MMAE). The estimated TI for LAV-ADC was at least 3 times greater than the HAV-ADC. The LAV- and HAV-ADCs showed similar levels of anti-tumor activity in the xenograft model, while the 111In-DTPA studies showed similar amounts of the ADCs in HT29 tumors. Although the LAV-ADC has ~2-fold slower blood clearance than the HAV-ADC, higher liver toxicity was observed with HAV-ADC. While the SPECT/CT 111In- and 124I- DTPA findings showed HAV-ADC has higher accumulation and rapid clearance in normal tissues, intravital microscopy (IVM) studies confirmed HAV mAb accumulates within hepatic sinusoidal endothelial cells while the LAV mAb does not. These results demonstrated that lowering the MET binding affinity provides a larger TI for MET-ADC. Decreasing the affinity of the ADC reduces the target mediated drug disposition (TMDD) to MET expressed in normal tissues while maintaining uptake/delivery to the tumor. This approach can be applied to multiple ADCs to improve the clinical outcomes.

CMC Regulatory Considerations for Antibody-Drug Conjugates.

Antibody-drug conjugates unite the specificity and long circulation time of an antibody with the toxicity of a chemical cytostatic or otherwise active drug using appropriate chemical linkers to reduce systemic toxicity and increase therapeutic index. This combination of a large biological molecule and a small molecule creates an increase in complexity. Multiple production processes are required to produce the native antibody, the drug and the linker, followed by conjugation of afore mentioned entities to form the final antibody-drug conjugate. The connected processes further increase the number of points of control, resulting in necessity of additional specifications and intensified analytical characterization. By combining scientific understanding of the production processes with risk-based approaches, quality can be demonstrated at those points where control is required and redundant comparability studies, specifications or product characterization are avoided. Over the product development lifecycle, this will allow process qualification to focus on those areas critical to quality and prevent redundant studies. The structure of the module 3 common technical document for an ADC needs to reflect each of the production processes and the combined overall approach to quality. Historically, regulatory authorities have provided varied expectations on its structure. This paper provides an overview of essential information to be included and shows that multiple approaches work as long as adequate cross-referencing is included.

SlTDC1 Overexpression Promoted Photosynthesis in Tomato under Chilling Stress by Improving CO2 Assimilation and Alleviating Photoinhibition.

Chilling causes a significant decline in photosynthesis in tomato plants. Tomato tryptophan decarboxylase gene 1 (SlTDC1) is the first rate-limiting gene for melatonin (MT) biosynthesis and is involved in the regulation of photosynthesis under various abiotic stresses. However, it is not clear whether SlTDC1 participates in the photosynthesis of tomato under chilling stress. Here, we obtained SlTDC1 overexpression transgenic tomato seedlings, which showed higher SlTDC1 mRNA abundance and MT content compared with the wild type (WT). The results showed that the overexpression of SlTDC1 obviously alleviated the chilling damage to seedlings in terms of the lower electrolyte leakage rate and hydrogen peroxide content, compared with the WT after 2 d of chilling stress. Moreover, the overexpression of SlTDC1 notably increased photosynthesis under chilling stress, which was related to the higher chlorophyll content, normal chloroplast structure, and higher mRNA abundance and protein level of Rubisco and RCA, as well as the higher carbon metabolic capacity, compared to the WT. In addition, we found that SlTDC1-overexpressing seedlings showed higher Wk (damage degree of OEC on the PSII donor side), φEo (quantum yield for electron transport in the PSII reaction center), and PIABS (photosynthetic performance index) than WT seedlings after low-temperature stress, implying that the overexpression of SlTDC1 decreased the damage to the reaction center and donor-side and receptor-side electron transport of PSII and promoted PSI activity, as well as energy absorption and distribution, to relieve the photoinhibition induced by chilling stress. Our results support the notion that SlTDC1 plays a vital role in the regulation of photosynthesis under chilling stress.

Impact of IgG subclass on monoclonal antibody developability.

IgG-based monoclonal antibody therapeutics, which are mainly IgG1, IgG2, and IgG4 subclasses or related variants, have dominated the biotherapeutics field for decades. Multiple laboratories have reported that the IgG subclasses possess different molecular characteristics that can affect their developability. For example, IgG1, the most popular IgG subclass for therapeutics, is known to have a characteristic degradation pathway related to its hinge fragility. However, there remains a paucity of studies that systematically evaluate the IgG subclasses on manufacturability and long-term stability. We thus conducted a systematic study of 12 mAbs derived from three sets of unrelated variable regions, each cloned into IgG1, an IgG1 variant with diminished effector functions, IgG2, and a stabilized IgG4 variant with further reduced FcγR interaction, to evaluate the impact of IgG subclass on manufacturability and high concentration stability in a common formulation buffer matrix. Our evaluation included Chinese hamster ovary cell productivity, host cell protein removal efficiency, N-linked glycan structure at the conserved N297 Fc position, solution appearance at high concentration, and aggregate growth, fragmentation, charge variant profile change, and post-translational modification upon thermal stress conditions or long-term storage at refrigerated temperature. Our results elucidated molecular attributes that are common to all IgG subclasses, as well as those that are unique to certain Fc domains, providing new insight into the effects of IgG subclass on antibody manufacturability and stability. These learnings can be used to enable a balanced decision on IgG subclass selection for therapeutic antibodies and aid in acceleration of their product development process.

Generative machine learning-based multi-objective process parameter optimization towards energy and quality of injection molding.

The high energy intensity and rigorous quality demand of injection molding have received significant interest under the background of the soaring production of global plastic industry. As multiple parts can be produced in a multi-cavity mold during one operation cycle, the weight differences of these parts have been demonstrated to reflect their quality performance. In this regard, this study incorporated this fact and developed a generative machine learning-based multi-objective optimization model. Such model can predict the qualification of parts produced under different processing variables and further optimize processing variables of injection molding for minimal energy consumption and weight difference amongst parts in one cycle. Statistical assessment via F1-score and R2 was performed to evaluate the performance of the algorithm. In addition, to validate the effectiveness of our model, we conducted physical experiments to measure the energy profile and weight difference under varying parameter settings. Permutation-based mean square error reduction was adopted to specify the importance of parameters affecting energy consumption and quality of injection molded parts. Optimization results indicated that the processing parameters optimization could reduce ~ 8% energy consumption and ~ 2% weight difference compared with the average operation practices. Maximum speed and first-stage speed were identified as the dominating factors affecting quality performance and energy consumption, respectively. This study could contribute to the quality assurance of injection molded parts and facilitate energy efficient and sustainable plastic manufacturing.

Intravital Microscopy Reveals Unforeseen Biodistribution Within the Liver and Kidney Mechanistically Connected to the Clearance of a Bifunctional Antibody.

Bifunctional antibody (BfAb) therapeutics offer the potential for novel functionalities beyond those of the individual monospecific entities. However, combining these entities into a single molecule can have unpredictable effects, including changes in pharmacokinetics that limit the compound's therapeutic profile. A better understanding of how molecular modifications affect in vivo tissue interactions could help inform BfAb design. The present studies were predicated on the observation that a BfAb designed to have minimal off-target interactions cleared from the circulation twice as fast as the monoclonal antibody (mAb) from which it was derived. The present study leverages the spatial and temporal resolution of intravital microscopy (IVM) to identify cellular interactions that may explain the different pharmacokinetics of the two compounds. Disposition studies of mice demonstrated that radiolabeled compounds distributed similarly over the first 24 hours, except that BfAb accumulated approximately two- to -three times more than mAb in the liver. IVM studies of mice demonstrated that both distributed to endosomes of liver endothelia but with different kinetics. Whereas mAb accumulated rapidly within the first hour of administration, BfAb accumulated only modestly during the first hour but continued to accumulate over 24 hours, ultimately reaching levels similar to those of the mAb. Although neither compound was freely filtered by the mouse or rat kidney, BfAb, but not mAb, was found to accumulate over 24 hours in endosomes of proximal tubule cells. These studies demonstrate how IVM can be used as a tool in drug design, revealing unpredicted cellular interactions that are undetectable by conventional analyses. SIGNIFICANCE STATEMENT: Bifunctional antibodies offer novel therapeutic functionalities beyond those of the individual monospecific entities. However, combining these entities into a single molecule can have unpredictable effects, including undesirable changes in pharmacokinetics. Studies of the dynamic distribution of a bifunctional antibody and its parent monoclonal antibody presented here demonstrate how intravital microscopy can expand our understanding of the in vivo disposition of therapeutics, detecting off-target interactions that could not be detected by conventional pharmacokinetics approaches or predicted by conventional physicochemical analyses.

Abscisic Acid Mediates Salicylic Acid Induced Chilling Tolerance of Grafted Cucumber by Activating H2O2 Biosynthesis and Accumulation.

Grafting is widely applied to enhance the tolerance of some vegetables to biotic and abiotic stress. Salicylic acid (SA) is known to be involved in grafting-induced chilling tolerance in cucumber. Here, we revealed that grafting with pumpkin (Cucurbita moschata, Cm) as a rootstock improved chilling tolerance and increased the accumulation of SA, abscisic acid (ABA) and hydrogen peroxide (H2O2) in grafted cucumber (Cucumis sativus/Cucurbita moschata, Cs/Cm) leaves. Exogenous SA improved the chilling tolerance and increased the accumulation of ABA and H2O2 and the mRNA abundances of CBF1, COR47, NCED, and RBOH1. However, 2-aminoindan-2-phosphonic acid (AIP) and L-a-aminooxy-b-phenylpropionic acid (AOPP) (biosynthesis inhibitors of SA) reduced grafting-induced chilling tolerance, as well as the synthesis of ABA and H2O2, in cucumber leaves. ABA significantly increased endogenous H2O2 production and the resistance to chilling stress, as proven by the lower electrolyte leakage (EL) and chilling injury index (CI). However, application of the ABA biosynthesis inhibitors sodium tungstate (Na2WO4) and fluridone (Flu) abolished grafting or SA-induced H2O2 accumulation and chilling tolerance. SA-induced plant response to chilling stress was also eliminated by N,N'-dimethylthiourea (DMTU, an H2O2 scavenger). In addition, ABA-induced chilling tolerance was attenuated by DMTU and diphenyleneiodonium (DPI, an H2O2 inhibitor) chloride, but AIP and AOPP had little effect on the ABA-induced mitigation of chilling stress. Na2WO4 and Flu diminished grafting- or SA-induced H2O2 biosynthesis, but DMTU and DPI did not affect ABA production induced by SA under chilling stress. These results suggest that SA participated in grafting-induced chilling tolerance by stimulating the biosynthesis of ABA and H2O2. H2O2, as a downstream signaler of ABA, mediates SA-induced chilling tolerance in grafted cucumber plants.

A Cohort Study of Surgical Indexes, Postoperative Complications, Recovery Speed, and Prognosis of Stanford Type A Aortic Dissection Compared with Traditional Sun's Operation.

Objective: The objective is to explore the surgical index, postoperative complications, recovery speed, and prognosis of Stanford type A aortic dissection (AD) compared with traditional 'Sun's operation. Methods: One hundred patients with Stanford type A AD treated from February 2018 to February 2021 were enrolled in our hospital. Patients were randomly divided into control and research group. The former group underwent traditional Sun's surgery, and the latter group underwent combined debranching surgery. The general data, surgical indexes, total amount of blood transfusion, renal function 72 hours after operation, postoperative indexes during hospitalization, and follow-up results after discharge were compared between the two groups. Results: The CPB time, ACC time, operation time, and postoperative total drainage volume of the study group were all lower than those of the control group, and the intraoperative urine volume of the study group was higher than that of the control group (P < 0.05). The total amount of RBC infused in the study group was higher than that in the control group, while the total amount of PLT, cryoprecipitate, and plasma infusion in the study group was lower than that in the control group (P < 0.05). At 72 hours after operation, BUN, Scr, and UA in the study group were significantly lower than those in the control group (P < 0.05). The number of the secondary intubation, hemodialysis, neurological complications, and deaths in the study group was significantly lower than that in the control group (P < 0.05). Conclusion: Both Sun's operation and branch removal are more effective treatment methods, and the two different surgical methods have different indications, advantages, and disadvantages, so different surgical methods can be chosen according to different conditions for Stanford AD. The possible postoperative complications should be comprehensively analyzed in the clinical work in order to reduce the occurrence of postoperative complications and improve the cure rate.

Structure and Interaction of Ceramide-Containing Liposomes with Gold Nanoparticles as Characterized by SERS and Cryo-EM.

Due to the great potential of surface-enhanced Raman scattering (SERS) as local vibrational probe of lipid-nanostructure interaction in lipid bilayers, it is important to characterize these interactions in detail. The interpretation of SERS data of lipids in living cells requires an understanding of how the molecules interact with gold nanostructures and how intermolecular interactions influence the proximity and contact between lipids and nanoparticles. Ceramide, a sphingolipid that acts as important structural component and regulator of biological function, therefore of interest to probing, lacks a phosphocholine head group that is common to many lipids used in liposome models. SERS spectra of liposomes of a mixture of ceramide, phosphatidic acid, and phosphatidylcholine, as well as of pure ceramide and of the phospholipid mixture are reported. Distinct groups of SERS spectra represent varied contributions of the choline, sphingosine, and phosphate head groups and the structures of the acyl chains. Spectral bands related to the state of order of the membrane and moreover to the amide function of the sphingosine head groups indicate that the gold nanoparticles interact with molecules involved in different intermolecular relations. While cryogenic electron microscopy shows the formation of bilayer liposomes in all preparations, pure ceramide was found to also form supramolecular, concentric stacked and densely packed lamellar, nonliposomal structures. That the formation of such supramolecular assemblies supports the intermolecular interactions of ceramide is indicated by the SERS data. The unique spectral features that are assigned to the ceramide-containing lipid model systems here enable an identification of these molecules in biological systems and allow us to obtain information on their structure and interaction by SERS.

Effect of Environmental pH on Mineralization of Anaerobic Iron-Oxidizing Bacteria.

Freshwater lakes are often polluted with various heavy metals in the Anthropocene. The iron-oxidizing microorganisms and their mineralized products can coprecipitate with many heavy metals, including Al, Zn, Cu, Cd, and Cr. As such, microbial iron oxidation can exert a profound impact on environmental remediation. The environmental pH is a key determinant regulating microbial growth and mineralization and then influences the structure of the final mineralized products of anaerobic iron-oxidizing bacteria. Freshwater lakes, in general, are neutral-pH environments. Understanding the effects of varying pH on the mineralization of iron-oxidizing bacteria under neutrophilic conditions could aid in finding out the optimal pH values that promote the coprecipitation of heavy metals. Here, two typical neutrophilic Fe(II)-oxidizing bacteria, the nitrate-reducing Acidovorax sp. strain BoFeN1 and the anoxygenic phototrophic Rhodobacter ferrooxidans strain SW2, were selected for studying how their growth and mineralization response to slight changes in circumneutral pH. By employing focused ion beam/scanning electron microscopy (FIB-SEM) and transmission electron microscopy (TEM), we examined the interplay between pH changes and anaerobic iron-oxidizing bacteria and observed that pH can significantly impact the microbial mineralization process and vice versa. Further, pH-dependent changes in the structure of mineralized products of bacterial iron oxidation were observed. Our study could provide mechanical insights into how to manipulate microbial iron oxidation for facilitating remediation of heavy metals in the environment.

Melatonin Promotes the Chilling Tolerance of Cucumber Seedlings by Regulating Antioxidant System and Relieving Photoinhibition.

Chilling adversely affects the photosynthesis of thermophilic plants, which further leads to a decline in growth and yield. The role of melatonin (MT) in the stress response of plants has been investigated, while the mechanisms by which MT regulates the chilling tolerance of chilling-sensitive cucumber remain unclear. This study demonstrated that MT positively regulated the chilling tolerance of cucumber seedlings and that 1.0 µmol⋅L-1 was the optimum concentration, of which the chilling injury index, electrolyte leakage (EL), and malondialdehyde (MDA) were the lowest, while growth was the highest among all treatments. MT triggered the activity and expression of antioxidant enzymes, which in turn decreased hydrogen peroxide (H2O2) and superoxide anion (O2 ⋅-) accumulation caused by chilling stress. Meanwhile, MT attenuated the chilling-induced decrease, in the net photosynthetic rate (Pn) and promoted photoprotection for both photosystem II (PSII) and photosystem I (PSI), regarding the higher maximum quantum efficiency of PSII (Fv/Fm), actual photochemical efficiency (ΦPSII), the content of active P700 (ΔI/I0), and photosynthetic electron transport. The proteome analysis and western blot data revealed that MT upregulated the protein levels of PSI reaction center subunits (PsaD, PsaE, PsaF, PsaH, and PsaN), PSII-associated protein PsbA (D1), and ribulose-1,5-bisphosphate carboxylase or oxygenase large subunit (RBCL) and Rubisco activase (RCA). These results suggest that MT enhances the chilling tolerance of cucumber through the activation of antioxidant enzymes and the induction of key PSI-, PSII-related and carbon assimilation genes, which finally alleviates damage to the photosynthetic apparatus and decreases oxidative damage to cucumber seedlings under chilling stress.

Impact of IgG subclass on molecular properties of monoclonal antibodies.

Immunoglobulin G-based monoclonal antibodies (mAbs) have become a dominant class of biotherapeutics in recent decades. Approved antibodies are mainly of the subclasses IgG1, IgG2, and IgG4, as well as their derivatives. Over the decades, the selection of IgG subclass has frequently been based on the needs of Fc gamma receptor engagement and effector functions for the desired mechanism of action, while the effect on drug product developability has been less thoroughly characterized. One of the major reasons is the lack of systematic understanding of the impact of IgG subclass on the molecular properties. Several efforts have been made recently to compare molecular property differences among these IgG subclasses, but the conclusions from these studies are sometimes obscured by the interference from variable regions. To further establish mechanistic understandings, we conducted a systematic study by grafting three independent variable regions onto human IgG1, an IgG1 variant, IgG2, and an IgG4 variant constant domains and evaluating the impact of subclass and variable regions on their molecular properties. Structural and computational analysis revealed specific molecular features that potentially account for the differential behavior of the IgG subclasses observed experimentally. Our data indicate that IgG subclass plays a significant role on molecular properties, either through direct effects or via the interplay with the variable region, the IgG1 mAbs tend to have higher solubility than either IgG2 or IgG4 mAbs in a common pH 6 buffer matrix, and solution behavior relies heavily on the charge status of the antibody at the desirable pH.

Nitric Oxide Functions as a Downstream Signal for Melatonin-Induced Cold Tolerance in Cucumber Seedlings.

Melatonin (MT) and nitric oxide (NO) are two multifunctional signaling molecules that are involved in the response of plants to abiotic stresses. However, how MT and NO synergize in response to cold stress affecting plants is still not clear. In this study, we found that endogenous MT accumulation under cold stress was positively correlated with cold tolerance in different varieties of cucumber seedlings. The data presented here also provide evidence that endogenous NO is involved in the response to cold stress. About 100 µM MT significantly increased the nitrate reductase (NR) activity, NR-relative messenger RNA (mRNA) expression, and endogenous NO accumulation in cucumber seedlings. However, 75 µM sodium nitroprusside (SNP, a NO donor) showed no significant effect on the relative mRNA expression of tryptophan decarboxylase (TDC), tryptamine-5-hydroxylase (T5H), serotonin-N-acetyltransferase (SNAT), or acetylserotonin O-methyltransferase (ASMT), the key genes for MT synthesis and endogenous MT levels. Compared with H2O treatment, both MT and SNP decreased electrolyte leakage (EL), malondialdehyde (MDA), and reactive oxygen species (ROS) accumulation by activating the antioxidant system and consequently mitigated cold damage in cucumber seedlings. MT and SNP also enhanced photosynthetic carbon assimilation, which was mainly attributed to an increase in the activity and mRNA expression of the key enzymes in the Calvin-Benson cycle. Simultaneously, MT- and SNP-induced photoprotection for both photosystem II (PSII) and photosystem I (PSI) in cucumber seedlings, by stimulating the PsbA (D1) protein repair pathway and ferredoxin-mediated NADP+ photoreduction, respectively. Moreover, exogenous MT and SNP markedly upregulated the expression of chilling response genes, such as inducer of CBF expression (ICE1), C-repeat-binding factor (CBF1), and cold-responsive (COR47). MT-induced cold tolerance was suppressed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO, a specific scavenger of NO). However, p-chlorophenylalanine (p-CPA, a MT synthesis inhibitor) did not affect NO-induced cold tolerance. Thus, novel results suggest that NO acts as a downstream signal in the MT-induced plant tolerance to cold stress.

Salicylic Acid Is Involved in Rootstock-Scion Communication in Improving the Chilling Tolerance of Grafted Cucumber.

Salicylic acid (SA) has been proven to be a multifunctional signaling molecule that participates in the response of plants to abiotic stresses. In this study, we used cold-sensitive cucumber and cold-tolerant pumpkin as experimental materials to examine the roles of SA in root-shoot communication responses to aerial or/and root-zone chilling stress in own-root and hetero-root grafted cucumber and pumpkin plants. The results showed that pumpkin (Cm) rootstock enhanced the chilling tolerance of grafted cucumber, as evidenced by the observed lower levels of electrolyte leakage (EL), malondialdehyde (MDA), and higher photosynthetic rate (Pn) and gene expression of Rubisco activase (RCA). However, cucumber (Cs) rootstock decreased the chilling tolerance of grafted pumpkins. Cs/Cm plants showed an increase in the mRNA expression of C-repeat-binding factor (CBF1), an inducer of CBF expression (ICE1), and cold-responsive (COR47) genes and CBF1 protein levels in leaves under 5/25 and 5/5°C stresses, or in roots under 25/5 and 5/5°C stresses, respectively, compared with the Cs/Cs. Chilling stress increased the endogenous SA content and the activity of phenylalanine ammonia-lyase (PAL), and the increase in SA content and activity of PAL in Cs/Cm plants was much higher than in Cs/Cs plants. Transcription profiling analysis revealed the key genes of SA biosynthesis, PAL, ICS, and SABP2 were upregulated, while SAMT, the key gene of SA degradation, was downregulated in Cs/Cm leaves, compared with Cs/Cs leaves under chilling stress. The accumulation of SA in the Cs/Cm leaves was mainly attributed to an increase in SA biosynthesis in leaves and that in transport from roots under aerial and root-zone chilling stress, respectively. In addition, exogenous SA significantly upregulated the expression level of cold-responsive (COR) genes, enhanced actual photochemical efficiency (Φ PSII), maximum photochemical efficiency (F v/F m), and Pn, while decreased EL, MDA, and CI in grafted cucumber. These results suggest that SA is involved in rootstock-scion communication and grafting-induced chilling tolerance by upregulating the expression of COR genes in cucumber plants under chilling stress.

Ultrasound-boosted selectivity of CO in CO2 electrochemical reduction.

Among the possible products of CO2 electrochemical reduction, CO plays a unique and vital role, which can be an ideal feedstock for further reduction to C2+ products, and also the important component of syngas that can be used as feedstock for value-added chemicals and fuels. However, it is still a challenge to tune the CO selectivity on Cu electrode. Here we newly construct an ultrasound-assisted electrochemical method for CO2 reduction, which can tune the selectivity of CO2 to CO from less than 10% to >80% at -1.18 V versus (vs.) reversible hydrogen electrode (RHE). The partial current density of CO production is significantly improved by 15 times. By in-situ Raman study, the dominating factor for the improved CO production is attributed to the accelerated desorption of *CO intermediate. This work provides a facile method to tune the product selectivity in CO2 electrochemical reduction.

Pharmacokinetic Developability and Disposition Profiles of Bispecific Antibodies: A Case Study with Two Molecules.

Bispecific antibodies (BsAb) that engage multiple pathways are a promising therapeutic strategy to improve and prolong the efficacy of biologics in complex diseases. In the early stages of discovery, BsAbs often exhibit a broad range of pharmacokinetic (PK) behavior. Optimization of the neonatal Fc receptor (FcRn) interactions and removal of undesirable physiochemical properties have been used to improve the 'pharmacokinetic developability' for various monoclonal antibody (mAb) therapeutics, yet there is a sparsity of such information for BsAbs. The present work evaluated the influence of FcRn interactions and inherent physiochemical properties on the PK of two related single chain variable fragment (scFv)-based BsAbs. Despite their close relation, the two BsAbs exhibit disparate PK in cynomolgus monkeys with BsAb-1 having an aberrant clearance of ~2 mL/h/kg and BsAb-2 displaying a an ~10-fold slower clearance (~0.2 mL/h/kg). Evaluation of the physiochemical characteristics of the molecules, including charge, non-specific binding, thermal stability, and hydrophobic properties, as well as FcRn interactions showed some differences. In-depth drug disposition results revealed that a substantial disparity in the complete release from FcRn at a neutral pH is a primary factor contributing to the rapid clearance of the BsAb-1 while other biophysical characteristics were largely comparable between molecules.

Au nanoring arrays as surface enhanced Raman spectroscopy substrate for chemical component study of individual atmospheric aerosol particle.

Monolayer-ordered gold nanoring arrays were prepared by ion-sputtering method and used as surface enhanced Raman spectroscopy (SERS) substrates to test the individual atmospheric aerosols particle. Compared to other methods used for testing atmospheric aerosols particles, the collection and subsequent detection in our work is performed directly on the gold nanoring SERS substrate without any treatment of the analyte. The SERS performance can be tuned by changing the depth of the gold nanoring cavity as originating from coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field exhibits uniform enhancement and polarization in the ordered Au nanoring substrate, which can improve the accuracy for detecting atmospheric aerosol particles. Combined with Raman mapping, the information about chemical composition of individual atmospheric aerosols particle and distribution of specific components can be presented visually. The results show the potential of SERS in enabling improved analysis of aerosol particle chemical composition, mixing state, and other related physicochemical properties.

Photochemical Oxidation of Water-Soluble Organic Carbon (WSOC) on Mineral Dust and Enhanced Organic Ammonium Formation.

Water-soluble organic carbon (WSOC), which is closely related to biogenic emissions, is of great importance in the atmosphere for its ubiquitous existence and rich abundance. Levoglucosan, a typical WSOC, is usually considered to be stable and thus used as a tracer of biomass burning. However, we found that levoglucosan can be photo-oxidized on mineral dust, with formic acid, oxalic acid, glyoxylic acid, 2,3-dioxopropanoic acid, dicarbonic acid, performic acid, mesoxalaldehyde, 2-hydroxymalonaldehyde, carbonic formic anhydride, and 1,3-dioxolane-2,4-dione detected as main products. Further, we observed the heterogeneous uptake of NH3 promoted by the carboxylic acids stemming from the photocatalytic oxidation (PCO) of levoglucosan. The mineral-dust-initiated PCO of levoglucosan and enhanced heterogeneous uptake of NH3, which are highly influenced by irradiation and moisture conditions, were for the first time revealed. The reaction mechanisms and pathways were studied in detail by diffuse reflection infrared Fourier transform spectroscopy (DRIFTS), high-pressure photon ionization time-of-flight mass spectrometry (HPPI-ToF-MS) and flow reactor systems. Diverse WSOC constituents were studied as well, and the reactivity toward NH3 is related to the number of hydroxyl groups of the WSOC molecules. This work reveals a new precursor of secondary organic aerosols and provides experimental evidence of the existence of organic ammonium salts in atmospheric particles.

Surface-Enhanced Raman Spectroscopy Facilitates the Detection of Microplastics <1 µm in the Environment.

Micro- and nanoplastics are considered one of the top pollutants that threaten the environment, aquatic life, and mammalian (including human) health. Unfortunately, the development of uncomplicated but reliable analytical methods that are sensitive to individual microplastic particles, with sizes smaller than 1 µm, remains incomplete. Here, we demonstrate the detection and identification of (single) micro- and nanoplastics by using surface-enhanced Raman spectroscopy (SERS) with Klarite substrates. Klarite is an exceptional SERS substrate; it is shaped as a dense grid of inverted pyramidal cavities made of gold. Numerical simulations demonstrate that these cavities (or pits) strongly focus incident light into intense hotspots. We show that Klarite has the potential to facilitate the detection and identification of synthesized and atmospheric/aquatic microplastic (single) particles, with sizes down to 360 nm. We find enhancement factors of up to 2 orders of magnitude for polystyrene analytes. In addition, we detect and identify microplastics with sizes down to 450 nm on Klarite, with samples extracted from ambient, airborne particles. Moreover, we demonstrate Raman mapping as a fast detection technique for submicron microplastic particles. The results show that SERS with Klarite is a facile technique that has the potential to detect and systematically measure nanoplastics in the environment. This research is an important step toward detecting nanoscale plastic particles that may cause toxic effects to mammalian and aquatic life when present in high concentrations.

Complete Photocatalytic Mineralization of Microplastic on TiO2 Nanoparticle Film.

Recently, the environmental impacts of microplastics have received extensive attention owing to their accumulation in the environment. However, developing efficient technology for the control and purification of microplastics is still a big challenge. Herein, we investigated the photocatalytic degradation of typical microplastics such as polystyrene (PS) microspheres and polyethylene (PE) over TiO2 nanoparticle films under UV light irradiation. TiO2 nanoparticle film made with Triton X-100 showed complete mineralization (98.40%) of 400-nm PS in 12 h, while degradation for varying sizes of PS was also studied. PE degradation experiment presented a high photodegradation rate after 36 h. CO2 was found as the main end product. The degradation mechanism and intermediates were studied by in situ DRIFTS and HPPI-TOFMS, showing the generation of hydroxyl, carbonyl, and carbon-hydrogen groups during the photodegradation of PS. This study provides a green and cost-efficient strategy for the control of microplastics contamination in the environment.