Long-Term Prevention of Biofilm Formation by Polycatechol-Based Supramolecular Assemblies with Low Molecular Weight Polymers on Surfaces.

Achievement of a stable surface coating with long-term resistance to biofilm formation remains a challenge. Catechol-based polymerization chemistry and surface deposition are used as tools for surface modification of diverse materials. However, the control of surface deposition of the coating, surface coverage, coating properties, and long-term protection against biofilm formation remain to be solved. We report a new approach based on supramolecular assembly to generate long-acting antibiofilm coating. Here, we utilized catechol chemistry in combination with low molecular weight amphiphilic polymers for the generation of such coatings. Screening studies with diverse low molecular weight (LMW) polymers and different catechols are utilized to identify lead compositions, which resulted in a thick coating with high surface coverage, smoothness, and antibiofilm activity. We have identified that small supramolecular assemblies (∼10 nm) formed from a combination of polydopamine and LMW poly(N-vinyl caprolactam) (PVCL) resulted in relatively thick coating (∼300 nm) with excellent surface coverage in comparison to other polymers and catechol combinations. The coating properties, such as thickness (10-300 nm) and surface hydrophilicity (with water contact angle: 20-60°), are readily controlled. The optimal coating composition showed excellent antibiofilm properties with long-term (>28 days) antibiofilm activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains. We further utilized the combination of optimal binary coating with silver to generate a coating with sustained release of silver ions, resulting in killing both adhered and planktonic bacteria and preventing long-term surface bacterial colonization. The new coating method utilizing LMW polymers opens a new avenue for the development of a novel class of thick, long-acting antibiofilm coatings.

Aß42 and ROS dual-targeted multifunctional nanocomposite for combination therapy of Alzheimer's disease.

Amyloid-ß (Aß) readily misfolds into neurotoxic aggregates, generating high levels of reactive oxygen species (ROS), leading to progressive oxidative damage and ultimately cell death. Therefore, simultaneous inhibition of Aß aggregation and scavenging of ROS may be a promising therapeutic strategy to alleviate Alzheimer's disease pathology. Based on the previously developed antibody 1F12 that targets all forms of Aß42, we developed an Aß42 and ROS dual-targeting nanocomposite using biodegradable mesoporous silica nanoparticles as carriers to load ultra-small cerium oxide nanocrystals (bMSNs@Ce-1F12). By modifying the brain-targeted rabies virus glycoprotein 29 (RVG29-bMSNs@Ce-1F12), this intelligent nanocomposite can efficiently target brain Aß-rich regions. Combined with peripheral and central nervous system treatments, RVG29-bMSNs@Ce-1F12 can significantly alleviate AD symptoms by inhibiting Aß42 misfolding, accelerating Aß42 clearance, and scavenging ROS. Furthermore, this synergistic effect of ROS scavenging and Aß clearance exhibited by this Aß42 and ROS dual-targeted strategy also reduced the burden of hyperphosphorylated tau, alleviated glial cell activation, and ultimately improved cognitive function in APP/PS1 mice. Our findings indicate that RVG29-bMSNs@Ce-1F12 is a promising nanodrug that can facilitate multi-target treatment of AD.

Investigation on Adaptability and Applicability of Polymer-Mediated Cell Surface Engineering by Ligation with Transglutaminase.

Polymer-mediated cell surface engineering can be a powerful tool to modify the cell's biological behavior, but a simple ligation strategy must be identified. This manuscript assessed the use of transglutamination as a versatile and adaptable approach for cell surface engineering in various cellular models relevant to biomedical applications. This enzymatic approach was evaluated for its feasibility and potential for conjugating polymers to diverse cell surfaces and its biological effects. Transglutaminase-mediated ligation was successfully performed at temperatures ranging from 4 to 37 °C in as quickly as 30 min, while maintaining biocompatibility and preserving cell viability. This approach was successfully applied to nine different cell surfaces (including adherent cells and suspension cells) by optimizing the enzyme source (guinea pig liver vs microbial), buffer compositions, and incubation conditions. Finally, polymer-mediated cell surface engineering using transglutaminase exhibited immunocamouflage abilities for endothelial cells, T cells, and red blood cells by preventing the recognition of cell surface proteins by antibodies. Employing transglutaminase in polymer-mediated cell surface engineering is a promising approach to maximize its application in cell therapy and other biomedical applications.

Sensitive detection of multiple blood biomarkers via immunomagnetic exosomal PCR for the diagnosis of Alzheimer's disease.

Blood exosomes are emerging as potential biomarkers for diagnosing brain diseases such as Alzheimer's disease (AD). There is currently a lack of an ultrasensitive technology for identifying core AD biomarkers in blood exosomes to optimize the utility of biomarkers in clinical practice. Here, an immunomagnetic exosomal polymerase chain reaction (iMEP) platform was developed using DNA-conjugated antibodies for the rapid detection of amyloid-ß (Aß1-40 and Aß1-42) and phosphorylated tau (p-tau396,404 and p-tau181) in clinical blood exosomes. The toehold shift-mediated DNA affinity pulldown eliminates the high detection background, which allows the detection of biomarkers at concentrations down to 10 femtograms per milliliter. With the iMEP assay, exosomal Aß1-42 was more accurate in differentiating patients with AD from healthy individuals compared with exosomal p-tau181 and p-tau396,404, with a sensitivity of 95.0% and a specificity of 95.0%. The iMEP technique is also adept at quantifying the levels of different exosomal biomarkers associated with disease pathogenesis.

Learning based motion artifacts processing in fNIRS: a mini review.

This paper provides a concise review of learning-based motion artifacts (MA) processing methods in functional near-infrared spectroscopy (fNIRS), highlighting the challenges of maintaining optimal contact during subject movement, which can lead to MA and compromise data integrity. Traditional strategies often result in reduced reliability of the hemodynamic response and statistical power. Recognizing the limited number of studies focusing on learning-based MA removal, we examine 315 studies, identifying seven pertinent to our focus area. We discuss the current landscape of learning-based MA correction methods and highlight research gaps. Noting the absence of standard evaluation metrics for quality assessment of MA correction, we suggest a novel framework, integrating signal and model quality considerations and employing metrics like ΔSignal-to-Noise Ratio (ΔSNR), confusion matrix, and Mean Squared Error. This work aims to facilitate the application of learning-based methodologies to fNIRS and improve the accuracy and reliability of neurovascular studies.

Ultrasensitive and point-of-care detection of plasma phosphorylated tau in Alzheimer's disease using colorimetric and surface-enhanced Raman scattering dual-readout lateral flow assay.

Phosphorylation of tau at Ser (396, 404) (p-tau396,404) is one of the earliest phosphorylation events, and plasma p-tau396,404 level appears to be a potentially promising biomarker of Alzheimer's disease (AD). The low abundance and easy degradation of p-tau in the plasma make the lateral flow assay (LFA) a suitable choice for point-of-care detection of plasma p-tau396,404 levels. Herein, based on our screening of a pair of p-tau396,404-specific antibodies, we developed a colorimetric and surface-enhanced Raman scattering (SERS) dual-readout LFA for the rapid, highly sensitive, and robust detection of plasma p-tau396,404 levels. This LFA realized a detection limit of 60 pg/mL by the naked eye or 3.8 pg/mL by SERS without cross-reacting with other tau species. More importantly, LFA rapidly and accurately differentiated AD patients from healthy controls, suggesting that it has the potential for clinical point-of-care application in AD diagnosis. This dual-readout LFA has the advantages of simple operation, rapid, and ultra-sensitive detection, providing a new way for early AD diagnosis and intervention, especially in primary and community AD screening. Electronic Supplementary Material: Supplementary material (characterization of AuNPs and 4-MBA@AuNP probe; the optimal 4-MBA load for AuNPs; the optimal K2CO3 volumes for 4-MBA@AuNP-3G5 conjugates; the optimal 3G5 load for 4-MBA@AuNP conjugates; effect of NaCl concentration on 4-MBA@AuNP-3G5 stability; the linear curve of T-line color and SERS intensity versus different p-tau396,404 concentrations; the comparison of colorimetric-based LFA test results and the diagnosis results; Raman intensities and antibody activity of 4-MBA@AuNP-3G5 before and after storage; colorimetric intensity of dual-readout LFA detecting different concentrations of p-tau396,404 protein; sequence of synthesized peptides used in this study; information of the participants in this study; the information of antibodies used in this study) is available in the online version of this article at 10.1007/s12274-022-5354-4.

An In Situ Study on Nanozyme Performance to Optimize Nanozyme-Strip for Aß Detection.

The nanozyme-strip is a novel POCT technology which is different from the conventional colloidal gold strip. It primarily utilizes the catalytic activity of nanozyme to achieve a high-sensitivity detection of target by amplifying the detection signal. However, previous research has chiefly focused on optimizing nanozyme-strip from the perspective of increasing nanozyme activity, little is known about other physicochemical factors. In this work, three sizes of Fe3O4 nanozyme and three sizes of CoFe2O4 nanozyme were used to investigate the key factors of nanozyme-strip for optimizing and improving its detection performance. We found that three sizes of Fe3O4 nanozyme all gather at the bottom of the nitrocellulose (NC) membrane, and three sizes of CoFe2O4 nanozyme migrate smoothly on the NC membrane, respectively. After color development, the surface of NC membranes distributed with CoFe2O4 peroxidase nanozymes had significant color change. Experimental results show that CoFe2O4 nanozymes had better dispersity than Fe3O4 nanozymes in an aqueous solution. We observed that CoFe2O4 nanozymes with smaller particle size migrated to the middle of the NC membrane with a higher number of particles. According to the results above, 55 ± 6 nm CoFe2O4 nanozyme was selected to prepare the nanozyme probe and achieved a highly sensitive detection of Aß42Os on the nanozyme-strip. These results suggest that nanozyme should be comprehensively evaluated in its dispersity, the migration on NC membrane, and the peroxidase-like activity to determine whether it can be applied to nanozyme-strip.

Smart thrombosis inhibitors without bleeding side effects via charge tunable ligand design.

Current treatments to prevent thrombosis, namely anticoagulants and platelets antagonists, remain complicated by the persistent risk of bleeding. Improved therapeutic strategies that diminish this risk would have a huge clinical impact. Antithrombotic agents that neutralize and inhibit polyphosphate (polyP) can be a powerful approach towards such a goal. Here, we report a design concept towards polyP inhibition, termed macromolecular polyanion inhibitors (MPI), with high binding affinity and specificity. Lead antithrombotic candidates are identified through a library screening of molecules which possess low charge density at physiological pH but which increase their charge upon binding to polyP, providing a smart way to enhance their activity and selectivity. The lead MPI candidates demonstrates antithrombotic activity in mouse models of thrombosis, does not give rise to bleeding, and is well tolerated in mice even at very high doses. The developed inhibitor is anticipated to open avenues in thrombosis prevention without bleeding risk, a challenge not addressed by current therapies.

Robust Nanoparticle-Derived Lubricious Antibiofilm Coating for Difficult-to-Coat Medical Devices with Intricate Geometry.

A major medical device-associated complication is the biofilm-related infection post-implantation. One promising approach to prevent this is to coat already commercialized medical devices with effective antibiofilm materials. However, developing a robust high-performance antibiofilm coating on devices with a nonflat geometry remains unmet. Here, we report the development of a facile scalable nanoparticle-based antibiofilm silver composite coating with long-term activity applicable to virtually any objects including difficult-to-coat commercially available medical devices utilizing a catecholic organic-aqueous mixture. Using a screening approach, we have identified a combination of the organic-aqueous buffer mixture which alters polycatecholamine synthesis, nanoparticle formation, and stabilization, resulting in controlled deposition of in situ formed composite silver nanoparticles in the presence of an ultra-high-molecular-weight hydrophilic polymer on diverse objects irrespective of its geometry and chemistry. Methanol-mediated synthesis of polymer-silver composite nanoparticles resulted in a biocompatible lubricious coating with high mechanical durability, long-term silver release (∼90 days), complete inhibition of bacterial adhesion, and excellent killing activity against a diverse range of bacteria over the long term. Coated catheters retained their excellent activity even after exposure to harsh mechanical challenges (rubbing, twisting, and stretching) and storage conditions (>3 months stirring in water). We confirmed its excellent bacteria-killing efficacy (>99.999%) against difficult-to-kill bacteria (Proteus mirabilis) and high biocompatibility using percutaneous catheter infection mice and subcutaneous implant rat models, respectively, in vivo. The developed coating approach opens a new avenue to transform clinically used medical devices (e.g., urinary catheters) to highly infection-resistant devices to prevent and treat implant/device-associated infections.

Sulfated Hyperbranched and Linear Polyglycerols Modulate HMGB1 and Morphological Plasticity in Neural Cells.

The objective of this study was to establish if polyglycerols with sulfate or sialic acid functional groups interact with high mobility group box 1 (HMGB1), and if so, which polyglycerol could prevent loss of morphological plasticity in excitatory neurons in the hippocampus. Considering that HMGB1 binds to heparan sulfate and that heparan sulfate has structural similarities with dendritic polyglycerol sulfates (dPGS), we performed the experiments to show if polyglycerols can mimic heparin functions by addressing the following questions: (1) do dendritic and linear polyglycerols interact with the alarmin molecule HMGB1? (2) Does dPGS interaction with HMGB1 influence the redox status of HMGB1? (3) Can dPGS prevent the loss of dendritic spines in organotypic cultures challenged with lipopolysaccharide (LPS)? LPS plays a critical role in infections with Gram-negative bacteria and is commonly used to test candidate therapeutic agents for inflammation and endotoxemia. Pathologically high LPS concentrations and other stressful stimuli cause HMGB1 release and post-translational modifications. We hypothesized that (i) electrostatic interactions of hyperbranched and linear polysulfated polyglycerols with HMGB1 will likely involve sites similar to those of heparan sulfate. (ii) dPGS can normalize HMGB1 compartmentalization in microglia exposed to LPS and prevent dendritic spine loss in the excitatory hippocampal neurons. We performed immunocytochemistry and biochemical analyses combined with confocal microscopy to determine cellular and extracellular locations of HMGB1 and morphological plasticity. Our results suggest that dPGS interacts with HMGB1 similarly to heparan sulfate. Hyperbranched dPGS and linear sulfated polymers prevent dendritic spine loss in hippocampal excitatory neurons. MS/MS analyses reveal that dPGS-HMGB1 interactions result in fully oxidized HMGB1 at critical cysteine residues (Cys23, Cys45, and Cys106). Triply oxidized HMGB1 leads to the loss of its pro-inflammatory action and could participate in dPGS-mediated spine loss prevention. LPG-Sia exposure to HMGB1 results in the oxidation of Cys23 and Cys106 but does not normalize spine density.

Elevated Plasma Oligomeric Amyloid ß-42 Is Associated with Cognitive Impairments in Cerebral Small Vessel Disease.

Due to the heterogeneity of amyloid ß-42 (Aß42) species, the potential correlation between plasma oligomeric Aß42 (oAß42) and cognitive impairments in cerebral small vessel disease (CSVD) remains unclear. Herein, a sandwich ELISA for the specific detection of Aß42 oligomers (oAß42) and total Aß42 (tAß42) was developed based on sequence- and conformation-specific antibody pairs for the evaluation of plasma samples from a Chinese CSVD community cohort. After age and gender matching, 3-Tesla magnetic resonance imaging and multidimensional cognitive assessment were conducted in 134 CSVD patients and equal controls. The results showed that plasma tAß42 and oAß42 levels were significantly elevated in CSVD patients. By regression analysis, these elevations were correlated with the presence of CSVD and its imaging markers (i.e., white matter hyperintensities). Plasma Aß42 tests further strengthened the predictive power of vascular risk factors for the presence of CSVD. Relative to tAß42, oAß42 showed a closer correlation with memory domains evaluated by neuropsychological tests. In conclusion, this sensitive ELISA protocol facilitated the detection of plasma Aß42; Aß42, especially its oligomeric form, can serve as a biosensor for the presence of CSVD and associated cognitive impairments represented by memory domains.

Colorimetric and surface-enhanced Raman scattering dual-mode magnetic immunosensor for ultrasensitive detection of blood phosphorylated tau in Alzheimer's disease.

Phosphorylation of tau at Ser 396, 404 (p-tau396,404) is the earliest phosphorylation event and a promising biomarker for the early diagnosis of Alzheimer's disease (AD). However, the detection of blood p-tau is challenging because of its low abundance, easy degradation, and complex formation with various blood proteins or cells, often leading to the underestimation of p-tau levels in conventional plasma-based assays. Herein, we developed a colorimetric and surface-enhanced Raman scattering (SERS) dual-mode magnetic immunosensor for highly sensitive, specific, and robust detection of p-tau396,404 in whole blood samples. The detection assay was based on an immunoreaction between p-tau396,404 proteins, wherein antibody-modified superparamagnetic iron oxide nanoparticles act as recognition elements to capture p-tau396,404 in blood, and then horseradish peroxidase- and Raman tags label the corresponding paired antibody as a reporter to provide high signal-to-noise ratios for the immunosensor. This dual-mode immunosensor achieved identified as low as 1.5 pg/mL of p-tau396,404 in the blood in SERS mode and 24 pg/mL in colorimetric mode by the naked eye. More importantly, this immunosensor rapidly and accurately distinguished AD patients from healthy individuals based on blood p-tau396,404 levels, and also had the potential to distinguish AD patients of different severities. Therefore, the dual-mode immunosensor is promising for rapid clinical diagnosis of AD, especially in large-scale AD screening.

Dual-targeted magnetic mesoporous silica nanoparticles reduce brain amyloid-ß burden via depolymerization and intestinal metabolism.

Rationale: Active removal of excess peripheral amyloid-ß (Aß) can potentially treat Alzheimer's disease (AD). However, the peripheral clearance of Aß using an anti-Aß monoclonal antibody (mAb) cannot remove PET-detectable Aß within the brain. This may be due to the inability of mAb to cross the blood-brain barrier (BBB) to degrade insoluble brain Aß plaques and block liver dysfunction. Methods: We developed a dual-targeted magnetic mesoporous silica nanoparticle (HA-MMSN-1F12) through surface-coupled Aß42-targeting antibody 1F12 and CD44-targeting ligand hyaluronic acid (HA). Results: HA-MMSN-1F12 had a high binding affinity toward Aß42 oligomers (Kd = 1.27 ± 0.34 nM) and revealed robust degradation of Aß42 aggregates. After intravenous administration of HA-MMSN-1F12 into ten-month-old APP/PS1 mice for three weeks (4 mg/kg/week), HA-MMSN-1F12 could cross the BBB and depolymerize brain Aß plaques into soluble Aß species. In addition, it also avoided hepatic uptake and excreted captured Aß species through intestinal metabolism, thereby reducing brain Aß load and neuroinflammation and improving memory deficits of APP/PS1 mice. Furthermore, the biochemical analysis showed that HA-MMSN-1F12 did not detect any toxic side effects on the liver and kidney. Thus, the efficacy of HA-MMSN-1F12 is associated with the targeted degradation of insoluble brain Aß plaques, avoidance of non-specific hepatic uptake, and excretion of peripheral Aß through intestinal metabolism. Conclusions: The study provides a new avenue for treating brain diseases by excreting disease-causing biohazards using intestinal metabolism.

Mesoporous silica nanoparticle-encapsulated Bifidobacterium attenuates brain Aß burden and improves olfactory dysfunction of APP/PS1 mice by nasal delivery.

BACKGROUND: Dysbiosis or imbalance of gut microbiota in Alzheimer's disease (AD) affects the production of short-chain fatty acids (SCFAs), whereas exogenous SCFAs supplementation exacerbates brain Aß burden in APP/PS1 mice. Bifidobacterium is the main producer of SCFAs in the gut flora, but oral administration of Bifidobacterium is ineffective due to strong acids and bile salts in the gastrointestinal tract. Therefore, regulating the levels of SCFAs in the gut is of great significance for AD treatment. METHODS: We investigated the feasibility of intranasal delivery of MSNs-Bifidobacterium (MSNs-Bi) to the gut and their effect on behavior and brain pathology in APP/PS1 mice. RESULTS: Mesoporous silica nanospheres (MSNs) were efficiently immobilized on the surface of Bifidobacterium. After intranasal administration, fluorescence imaging of MSNs-Bi in the abdominal cavity and gastrointestinal tract revealed that intranasally delivered MSNs-Bi could be transported through the brain to the peripheral intestine. Intranasal administration of MSNs-Bi not only inhibited intestinal inflammation and reduced brain Aß burden but also improved olfactory sensitivity in APP/PS1 mice. CONCLUSIONS: These findings suggested that restoring the balance of the gut microbiome contributes to ameliorating cognitive impairment in AD, and that intranasal administration of MSNs-Bi may be an effective therapeutic strategy for the prevention of AD and intestinal disease.

Durable Surfaces from Film-Forming Silver Assemblies for Long-Term Zero Bacterial Adhesion without Toxicity.

The long-term prevention of biofilm formation on the surface of indwelling medical devices remains a challenge. Silver has been reutilized in recent years for combating biofilm formation due to its indisputable bactericidal potency; however, the toxicity, low stability, and short-term activity of the current silver coatings have limited their use. Here, we report the development of silver-based film-forming antibacterial engineered (SAFE) assemblies for the generation of durable lubricous antibiofilm surface long-term activity without silver toxicity that was applicable to diverse materials via a highly scalable dip/spray/solution-skinning process. The SAFE coating was obtained through a large-scale screening, resulting in effective incorporation of silver nanoparticles (∼10 nm) into a stable nonsticky coating with high surface hierarchy and coverage, which guaranteed sustained silver release. The lead coating showed zero bacterial adhesion over a 1 month experiment in the presence of a high load of diverse bacteria, including difficult-to-kill and stone-forming strains. The SAFE coating showed high biocompatibility and excellent antibiofilm activity in vivo.

Current trends in blood biomarker detection and imaging for Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disease that causes cognitive impairments in areas such as memory, language, and reasoning. Currently, a definitive diagnosis of AD is based on histological examination of brain specimens. Hence, it is imperative to develop practical AD detection and diagnostic tools. Blood tests are less invasive, more accessible than lumbar puncture for cerebrospinal fluid collection, and are an ideal source of biomarkers. Various detection techniques related to AD biomarkers have emerged, and have been used in the detection of AD blood samples. However, to improve the diagnostic accuracy of AD blood testing in clinical practice, basic research needs more detailed guidelines to determine how to implement the use of biomarkers in diagnostic procedures. Therefore, combining blood biomarker detection with imaging markers may help improve the accuracy of AD diagnosis. In this review, we discuss the development trend of AD-related blood biomarker detection technologies including optoelectrical analysis platforms, and look forward to the development prospects of joint detection with optoelectronic and imaging technologies in clinical diagnosis.

Effect of low-dose esketamine on pain control and postpartum depression after cesarean section: a retrospective cohort study.

BACKGROUND: Esketamine is used to control postoperative pain and reduce postoperative depression in surgical patients. This study was performed to determine the effects of esketamine on pain control as well as postpartum depression (PPD) in pregnant women who underwent cesarean section (CS). METHODS: Pregnant women who underwent CS between March 2018 and February 2020 at our hospital were retrospectively reviewed. Parturients in the control group received 50 µg sufentanil citrate and 0.25 mg palonosetron hydrochloride, while those in the experimental group received additional 0.2-0.5 mg/kg esketamine. The primary outcomes included postoperative pain control according to the numeric rating scale (NRS) and the incidence of PPD according to the Edinburgh postnatal depression scale (EPDS). Multivariable linear regression analysis was performed to determine the relationship between the use of esketamine, pain control, and the incidence of PPD after CS. RESULTS: There were 132 parturients in the control group and 108 parturients in the esketamine group in this study. All NRS scores at rest at any time point were much lower in the esketamine group than those in the control group. Besides, NRS scores when coughing were also lower in the esketamine group within 24 hours. EPDS scores were lower in the esketamine group than those in the control group within 3 months postpartum. Esketamine acted as a protector of pain control and was confirmed to improve the incidence of PPD using multivariable linear regression. Parturients had dramatically better sleep quality within 1 week postpartum (P=0.044), and morphine consumption within 24 hours postpartum was lower in the esketamine group than in the control group (P<0.001). The quality of recovery within 3 months postpartum was also better in the esketamine group (P=0.001). A subgroup analysis of 2 subgroups divided according to the dose of esketamine was then performed, indicating no significant difference between the low-dose group and high-dose group in most included outcomes. CONCLUSIONS: This study confirmed the effects of esketamine on pain control and the incidence of PPD in pregnant women who underwent CS. Considering the potential adverse events, low-dose esketamine may be more suitable for pregnant women who have undergone CS.

Visualizing dynamic changes in PD-L1 expression in non-small cell lung carcinoma with radiolabeled recombinant human PD-1.

PURPOSE: Tumor heterogeneity limits the predictive value of PD-L1 expression and influences the outcomes of the immunohistochemical assay for therapy-induced changes in PD-L1 levels. This study aimed to determine the predictive value of PD-L1 for non-small cell lung carcinoma (NSCLC), thereby developing imaging agents to non-invasively image and examine the effect of the therapeutic response to PD-L1 blockade therapy. METHODS: A cohort of 102 patients with lung cancer was analyzed, and the prognostic significance of PD-L1 expression level was investigated. Recombinant human PD-1 ECD protein (rhPD1) was expressed, purified, and labeled with 64Cu for the evaluation of PD-L1 status in tumors. Mice subcutaneously bearing PD-L1 high-expressing tumor HCC827 and PD-L1 low-expressing tumor A549 were used to determine tracer-target specificity and examine the effect of therapeutic response to PD-L1 blockade therapy. RESULTS: PD-L1 was proved to be a good prognosis marker for NSCLC, and its expression was correlated with the histology of NSCLC. PET imaging revealed high tumor accumulation of 64Cu-NOTA-rhPD1 in HCC827 tumors (9.0 ± 0.5%ID/g), whereas it was 3.2 ± 0.4%ID/g in A549 tumors at 3 h post-injection. The lower tumor uptake (3.1 ± 0.3%ID/g) of 64Cu-labeled denatured rhPD1 in HCC827 tumors at 3 h post-injection (p < 0.001) demonstrated the target specificity of 64Cu-NOTA-rhPD1. Furthermore, PET showed that 64Cu-NOTA-rhPD1 sensitively monitored treatment-related changes in PD-L1 expression, and seemed to be superior to [18F]FDG. CONCLUSION: We identified PD-L1 as a good prognosis marker for surgically resected NSCLC and developed the PET tracer 64Cu-NOTA-rhPD1 with high target specificity for PD-L1.

Nanozyme sensor array based on manganese dioxide for the distinction between multiple amyloid ß peptides and their dynamic aggregation process.

The determination of the amyloid ß (Aß) peptide and its aggregation intermediates helps to understand the pathological mechanism of Alzheimer's disease (AD) caused by toxic amyloid fragments. Because of the transient and heterogeneous properties of Aß aggregates, it is very difficult to dynamically detect Aß and its aggregation intermediates. Herein, we successfully constructed a two-dimensional manganese dioxide (MnO2) nanozyme sensor array by modulating the peroxidase-mimicking activity using various Aß species and accurately distinguished among six types of Aß within 1 h through linear discriminant analysis (LDA), with a dynamic detection range of 0.01-500 nmol/L and a detection limit of 0.44 pmol/L. Subsequently, 30 unknown blind samples were used to verify the practicability of the sensor array, and all unknown samples were identified with 100% accuracy. It is worth noting that the sensor array successfully distinguished healthy individuals from AD patients using clinical blood samples. This study provides a convenient and reliable nanozyme biosensing system for detecting Aß species and their related aggregation processes.