Serum Leucine Aminopeptidase Activity Patterns Across Various Disease States: Potential Implications for Bleeding and Thrombosis Risk.

BACKGROUND: Disruptions in the pathways for activating and deactivating proteases in the bloodstream can lead to thrombosis and bleeding issues. Leucine aminopeptidases (LAPs), which are exopeptidases essential for regulating protein and peptide activities, are recognized as clinical biomarkers for liver diseases. However, the relationship between serum LAP activity and the risks of bleeding or thrombosis, as well as the identification of the specific tissues or organs that control LAP levels, is not well understood. METHODS: We performed a retrospective study to evaluate serum LAP activities in 149,360 patients with 47 different diseases and 9,449 healthy individuals. The analysis was conducted using SPSS V2.6, RStudio V.1.3.1073, and libraries in Python 3.8. RESULTS: Our research revealed that 21 of the 47 diseases studied showed increased median serum LAP activities, while 26 diseases were associated with significantly lower activities, especially those related to thrombosis. Furthermore, most diseases were found to have an increased risk of bleeding and thrombosis, indicated by higher Q25 and lower Q75 LAP activities compared to the control group. ROC analysis confirmed the effectiveness of LAP activities as biomarkers for specific conditions like hepatic encephalopathy, liver cancer, pancreatitis, and pancreatic cancer. Diseases were categorized into clusters with similar bleeding or thrombotic tendencies through principal component analysis. CONCLUSION: This study highlighted regulatory influence of the liver and pancreas on LAP levels. The established link between serum LAP concentrations and the risk of bleeding or thrombosis paved the way for the development of diagnostic and preventative approaches for various medical conditions.

Strong, tough, rapid-recovery, and fatigue-resistant hydrogels made of picot peptide fibres.

Hydrogels are promising soft materials as tissue engineering scaffolds, stretchable sensors, and soft robotics. Yet, it remains challenging to develop synthetic hydrogels with mechanical stability and durability similar to those of the connective tissues. Many of the necessary mechanical properties, such as high strength, high toughness, rapid recovery, and high fatigue resistance, generally cannot be established together using conventional polymer networks. Here we present a type of hydrogels comprising hierarchical structures of picot fibres made of copper-bound self-assembling peptide strands with zipped flexible hidden length. The redundant hidden lengths allow the fibres to be extended to dissipate mechanical load without reducing network connectivity, making the hydrogels robust against damage. The hydrogels possess high strength, good toughness, high fatigue threshold, and rapid recovery, comparable to or even outperforming those of articular cartilage. Our study highlights the unique possibility of tailoring hydrogel network structures at the molecular level to improve their mechanical performance.

An efficient CRISPR-Cas12a promoter editing system for crop improvement.

Promoter editing represents an innovative approach to introduce quantitative trait variation (QTV) in crops. However, an efficient promoter editing system for QTV needs to be established. Here we develop a CRISPR-Cas12a promoter editing (CAPE) system that combines a promoter key-region estimating model and an efficient CRISPR-Cas12a-based multiplexed or singular editing system. CAPE is benchmarked in rice to produce QTV continuums for grain starch content and size by targeting OsGBSS1 and OsGS3, respectively. We then apply CAPE for promoter editing of OsD18, a gene encoding GA3ox in the gibberellin biosynthesis pathway. The resulting lines carry a QTV continuum of semidwarfism without significantly compromising grain measures. Field trials demonstrated that the OsD18 promoter editing lines have the same yield performance and antilodging phenotype as the Green Revolution OsSD1 mutants in different genetic backgrounds. Hence, promoter editing of OsD18 generates a quantitative Green Revolution trait. Together, we demonstrate a CAPE-based promoter editing and tuning pipeline for efficient production of useful QTV continuum in crops.

Coarse-grained description of monounsaturated peroxidized phospholipid bilayers.

Lipid peroxides result from a reaction between cis-unsaturated lipid chains and singlet oxygen molecules leading to the addition of a peroxide OOH side group next to the acyl-chain double bond. It is now established that HP-POPC (hydroperoxidized POPC) molecules form stable, thin, and laterally expanded bilayers. The difference in the structural organization arises from the hydrophilic character of the OOH side group that has a strong affinity with the water interface region, leading to significant reorganization of the bilayer. In this article, we describe a coarse-grained (CG) model of POPC and DOPC lipid peroxides within the framework of the Martini CG force-field (v2.2), derived from experimental data. We then discuss extensively the predicted structure and the influence of hydration and show how shifting the position of the unsaturated bonds along the chain changes the structure. Finally, we provide electron and neutron scattering length density profiles of the simulated bilayers.

Efficient enumeration-selection computational strategy for adaptive chemistry.

Design problems of finding efficient patterns, adaptation of complex molecules to external environments, affinity of molecules to specific targets, dynamic adaptive behavior of chemical systems, reconstruction of 3D structures from diffraction data are examples of difficult to solve optimal design or inverse search problems. Nature inspires evolution strategies to solve design problems that are based on selection of successful adaptations and heritable traits over generations. To exploit this strategy in the creation of new materials, a concept of adaptive chemistry was proposed to provide a route for synthesis of self-adapting molecules that can fit to their environment. We propose a computational method of an efficient exhaustive search exploiting massive parallelization on modern GPUs, which finds a solution for an inverse problem by solving repetitively a direct problem in the mean field approximation. One example is the search for a composition of a copolymer that allows the polymer to translocate through a lipid membrane at a minimal time. Another example is a search of a copolymer sequence that maximizes the polymer load in the micelle defined by the radial core-shell potentials. The length and the composition of the sequence are adjusted to fit into the restricted environment. Hydrogen bonding is another pathway of adaptation to the environment through reversible links. A linear polymer that interacts with water through hydrogen bonds adjusts the position of hydrogen bonds along the chain as a function of the concentration field around monomers. In the last example, branching of the molecules is adjusted to external fields, providing molecules with annealed topology, that can be flexibly changed by changing external conditions. The method can be generalized and applied to a broad spectrum of design problems in chemistry and physics, where adaptive behavior in multi-parameter space in response to environmental conditions lead to non-trivial patterns or molecule architectures and compositions. It can further be combined with machine learning or other optimization techniques to explore more efficiently the parameter space.

CRISPR-Cas9 mediated OsMIR168a knockout reveals its pleiotropy in rice.

MicroRNA168 (MIR168) is a key miRNA that targets the main RNA-induced silencing complex component Argonaute 1 (AGO1) to regulate plant growth and environmental stress responses. However, the regulatory functions of MIR168 need to be further elucidated in rice. In this paper, we generated clean OsMIR168a deletion mutants by CRISPR-Cas9 strategy. We then phenotypically and molecularly characterized these mutants. The rice OsMIR168a mutants grew rapidly at the seedling stage, produced more tillers and matured early. Compared to the wild-type plants, the mutants were shorter at maturity and produced smaller spikelets and seeds. Analysis of gene expression showed that the transcription levels of OsMIR168a's target genes such as OsAGO1a, OsAGO1b and OsAGO1d were elevated significantly in the OsMIR168a mutants. Intriguingly, OsAGO18, a member of a new AGO clade that is conserved in monocots, was confirmed to be a target of OsMIR168a not only by informatic prediction but also by expression analysis and a cell-based cleavage assay in the OsMIR168a mutants. Many protein-coding genes and miRNAs showed differential expression in the OsMIR168a mutants, suggesting OsMIR168a exerts a major transcriptional regulatory role, likely through its potential target genes such as OsAGO1s and OsAGO18. KEGG enrichment analysis of these differentially expressed genes pointed to OsMIR168a's involvement in important processes such as plant hormone signalling transduction and plant-pathogen interaction. These data collectively support that the complex regulation module of OsMIR168a-OsAGO1/OsAGO18-miRNAs-target genes contributes to agronomically important traits, which sheds light on miRNA-mediated crop breeding.

Systems biomarker characteristics of circulating alkaline phosphatase activities for 48 types of human diseases.

BACKGROUND: Most human diseases are accompanied by systems changes. Systems biomarkers should reflect such changes. The phosphorylation and dephosphorylation of biomolecules maintain human homeostasis. However, the systems biomarker characteristics of circulating alkaline phosphatase, a routine blood test conducted for many human diseases, have never been investigated. METHOD: This study retrieved the circulating alkaline phosphatase (ALP) activities from patients with 48 clinically confirmed diseases and healthy individuals from the database of our hospital during the past five years. A detailed analysis of the statistical characteristics of ALP was conducted, including quantiles, receiving operator curve (ROC), and principal component analysis. RESULTS: Among the 48 diseases, 45 had increased, and three had decreased median levels of ALP activities compared to the healthy control. Preeclampsia, hepatic encephalopathy, pancreatic cancer, and liver cancer had the highest median values, whereas nephrotic syndrome, lupus erythematosus, and nephritis had decreased median values compared to the healthy control. Further, area under curve (AUC) values were ranged between 0.61 and 0.87 for 19 diseases, and the ALP activities were the best systems biomarker for preeclampsia (AUC 0.87), hepatic encephalopathy (AUC 0.87), liver cancer (AUC 0.81), and pancreatic cancer (AUC 0.81). CONCLUSIONS: Alkaline phosphatase was a decent systems biomarker for 19 different types of human diseases. Understanding the molecular mechanisms of over-up-and-down-regulation of ALP activities might be the key to understanding the whole-body systems' reactions during specific disease progression.

Strong histamine torsion Raman spectrum enables direct, rapid, and ultrasensitive detection of allergic diseases.

Allergic diseases are closely related to degranulation and release of histamine and difficult to diagnose because non-allergic diseases also exhibit the same clinical symptoms as allergy. Here, we report direct, rapid, and ultrasensitive detection of histamine using low-frequency molecular torsion Raman spectroscopy. We show that the low-frequency (<200 cm-1) Raman spectral intensities are stronger by one order of magnitude than those of the high-frequency Raman ones. Density functional theory calculation and nuclear magnetic resonance spectroscopy identify the strong spectral feature to be from torsions of carbon-carbon single bonds, which produce large variations of the polarizability densities in the imidazole ring and ethyl amino side chain. Using an omniphobic substrate and surface plasmonic effect of Au@SiO2 nanoparticles, the detection limit (signal-noise ratio >3) of histamine reaches 10-8 g/L in water and 10-6 g/L in serum. This scheme thus opens new lines of inquiry regarding the clinical diagnosis of allergic diseases.

Ultrathin 2D Titanium Carbide MXene (Ti3 C2 Tx ) Nanoflakes Activate WNT/HIF-1α-Mediated Metabolism Reprogramming for Periodontal Regeneration.

Periodontal defect regeneration in severe periodontitis relies on the differentiation and proliferation of periodontal ligament cells (PDLCs). Recently, an emerging 2D nanomaterial, MXene (Ti3 C2 Tx ), has gained more and more attention due to the extensive antibacterial and anticancer activity, while its potential biomedical application on tissue regeneration remains unclear. Through a combination of experimental and multiscale simulation schemes, Ti3 C2 Tx has exhibited satisfactory biocompatibility and induced distinguish osteogenic differentiation of human PDLCs (hPDLCs), with upregulated osteogenesis-related genes. Ti3 C2 Tx manages to activate the Wnt/ß-catenin signaling pathway by enhancing the Wnt-Frizzled complex binding, thus stabilizing HIF-1α and altering metabolic reprogramming into glycolysis. In vivo, hPDLCs pretreated by Ti3 C2 Tx display excellent performance in new bone formation and osteoclast inhibition with enhanced RUNX2, HIF-1α, and ß-catenin in an experimental rat model of periodontal fenestration defects, indicating that this material has high efficiency of periodontal regeneration promotion. It is demonstrated in this work that Ti3 C2 Tx has highly efficient therapeutic effects in osteogenic differentiation and periodontal defect repairment.

Serum lactate dehydrogenase activities as systems biomarkers for 48 types of human diseases.

Most human diseases are systems diseases, and systems biomarkers are better fitted for diagnostic, prognostic, and treatment monitoring purposes. To search for systems biomarker candidates, lactate dehydrogenase (LDH), a housekeeping protein expressed in all living cells, was investigated. To this end, we analyzed the serum LDH activities from 172,933 patients with 48 clinically defined diseases and 9528 healthy individuals. Based on the median values, we found that 46 out of 48 diseases, leading by acute myocardial infarction, had significantly increased (p < 0.001), whereas gout and cerebral ischemia had significantly decreased (p < 0.001) serum LDH activities compared to the healthy control. Remarkably, hepatic encephalopathy and lung fibrosis had the highest AUCs (0.89, 0.80), sensitivities (0.73, 0.56), and specificities (0.90, 0.91) among 48 human diseases. Statistical analysis revealed that over-downregulation of serum LDH activities was associated with blood-related cancers and diseases. LDH activities were potential systems biomarker candidates (AUCs > 0.8) for hepatic encephalopathy and lung fibrosis.

Improved plant cytosine base editors with high editing activity, purity, and specificity.

Cytosine base editors (CBEs) are great additions to the expanding genome editing toolbox. To improve C-to-T base editing in plants, we first compared seven cytidine deaminases in the BE3-like configuration in rice. We found A3A/Y130F-CBE_V01 resulted in the highest C-to-T base editing efficiency in both rice and Arabidopsis. Furthermore, we demonstrated this A3A/Y130F cytidine deaminase could be used to improve iSpyMacCas9-mediated C-to-T base editing at A-rich PAMs. To showcase its applications, we first applied A3A/Y130F-CBE_V01 for multiplexed editing to generate microRNA-resistant mRNA transcripts as well as pre-mature stop codons in multiple seed trait genes. In addition, we harnessed A3A/Y130F-CBE_V01 for efficient artificial evolution of novel ALS and EPSPS alleles which conferred herbicide resistance in rice. To further improve C-to-T base editing, multiple CBE_V02, CBE_V03 and CBE_V04 systems were developed and tested in rice protoplasts. The CBE_V04 systems were found to have improved editing activity and purity with focal recruitment of more uracil DNA glycosylase inhibitors (UGIs) by the engineered single guide RNA 2.0 scaffold. Finally, we used whole-genome sequencing (WGS) to compare six CBE_V01 systems and four CBE_V04 systems for genome-wide off-target effects in rice. Different levels of cytidine deaminase-dependent and sgRNA-independent off-target effects were indeed revealed by WGS among edited lines by these CBE systems. We also investigated genome-wide sgRNA-dependent off-target effects by different CBEs in rice. This comprehensive study compared 21 different CBE systems, and benchmarked PmCDA1-CBE_V04 and A3A/Y130F-CBE_V04 as next-generation plant CBEs with high editing efficiency, purity, and specificity.

PAM-less plant genome editing using a CRISPR-SpRY toolbox.

The rapid development of the CRISPR-Cas9, -Cas12a and -Cas12b genome editing systems has greatly fuelled basic and translational plant research1-6. DNA targeting by these Cas nucleases is restricted by their preferred protospacer adjacent motifs (PAMs). The PAM requirement for the most popular Streptococcus pyogenes Cas9 (SpCas9) is NGG (N = A, T, C, G)7, limiting its targeting scope to GC-rich regions. Here, we demonstrate genome editing at relaxed PAM sites in rice (a monocot) and the Dahurian larch (a coniferous tree), using an engineered SpRY Cas9 variant8. Highly efficient targeted mutagenesis can be readily achieved by SpRY at relaxed PAM sites in the Dahurian larch protoplasts and in rice transgenic lines through non-homologous end joining (NHEJ). Furthermore, an SpRY-based cytosine base editor was developed and demonstrated by directed evolution of new herbicide resistant OsALS alleles in rice. Similarly, a highly active SpRY adenine base editor was developed based on ABE8e (ref. 9) and SpRY-ABE8e was able to target relaxed PAM sites in rice plants, achieving up to 79% editing efficiency with high product purity. Thus, the SpRY toolbox breaks a PAM restriction barrier in plant genome engineering by enabling DNA editing in a PAM-less fashion. Evidence was also provided for secondary off-target effects by de novo generated single guide RNAs (sgRNAs) due to SpRY-mediated transfer DNA self-editing, which calls for more sophisticated programmes for designing highly specific sgRNAs when implementing the SpRY genome editing toolbox.

Beyond Risk: Bacterial Biofilms and Their Regulating Approaches.

Bacterial biofilms are complex surface attached communities of bacteria held together by self-produced polymer matrixs mainly composed of polysaccharides, secreted proteins, and extracellular DNAs. Bacterial biofilm formation is a complex process and can be described in five main phases: (i) reversible attachment phase, where bacteria non-specifically attach to surfaces; (ii) irreversible attachment phase, which involves interaction between bacterial cells and a surface using bacterial adhesins such as fimbriae and lipopolysaccharide (LPS); (iii) production of extracellular polymeric substances (EPS) by the resident bacterial cells; (iv) biofilm maturation phase, in which bacterial cells synthesize and release signaling molecules to sense the presence of each other, conducing to the formation of microcolony and maturation of biofilms; and (v) dispersal/detachment phase, where the bacterial cells depart biofilms and comeback to independent planktonic lifestyle. Biofilm formation is detrimental in healthcare, drinking water distribution systems, food, and marine industries, etc. As a result, current studies have been focused toward control and prevention of biofilms. In an effort to get rid of harmful biofilms, various techniques and approaches have been employed that interfere with bacterial attachment, bacterial communication systems (quorum sensing, QS), and biofilm matrixs. Biofilms, however, also offer beneficial roles in a variety of fields including applications in plant protection, bioremediation, wastewater treatment, and corrosion inhibition amongst others. Development of beneficial biofilms can be promoted through manipulation of adhesion surfaces, QS and environmental conditions. This review describes the events involved in bacterial biofilm formation, lists the negative and positive aspects associated with bacterial biofilms, elaborates the main strategies currently used to regulate establishment of harmful bacterial biofilms as well as certain strategies employed to encourage formation of beneficial bacterial biofilms, and highlights the future perspectives of bacterial biofilms.

Ecologically controlling insect and mite pests of tea plants with microbial pesticides: a review.

Insect and mite pests are damaging stressors that are threatening the cultivation of tea plants, which result in enormous crop loss. Over the years, the effectiveness of synthetic pesticides has allowed for its prominent application as a control strategy. However, the adverse effects of synthetic pesticides in terms of pesticide residue, environmental contamination and insect pest resistance have necessitated the need for alternative strategies. Meanwhile, microbial pesticides have been applied to tackle the damaging activities of the insect and mite pests of tea plants, and their performances were scientifically adjudged appreciable and environmental friendly. Herein, entomopathogenic microbes that were effective against tea geometrid (Ectropis obliqua Prout), tea green leafhopper (Empoasca onukii Matsuda), paraguay tea ampul (Gyropsylla spegazziniana), tea mosquito bug (Helopeltis theivora Waterhouse) and red spider mite (Oligonychus coffea Nietner) have been reviewed. The current findings revealed that microbial pesticides were effective and showed promising performances against these pests. Overall, this review has provided the basic and integrative information on the integrated pest management (IPM) tool(s) that can be utilized towards successful control of the aforementioned insect and mite pests.

Unexpected Cholesterol-Induced Destabilization of Lipid Membranes near Transmembrane Carbon Nanotubes.

Cholesterol is a crucial component of mammalian cell membranes that takes part in many vital processes. It is generally accepted that cholesterol stabilizes the membrane and induces transitions into ordered states. In contrast to expectations, we demonstrate that cholesterol can destabilize the membrane by creating a nanodomain around a perpendicularly embedded ultrashort carbon nanotube (CNT), and we show that cholesterol triggers the translocation of an ultrashort CNT through the cell membrane. Using atomistic simulations, we report the existence of a nanoscale domain around an ultrashort carbon nanotube within a crossover distance of 0.9 nm from the surface of the nanotube, where the properties of the bilayer are different from the bulk: the domain is characterized by increased fluctuations, increased thickness, and increased order of the lipids with respect to the bulk. Cholesterol decreases the thickness and order of lipids and increases the fluctuations with respect to a pure lipid bilayer. Experimentally, we confirm that cholesterol nanodomains provoke spontaneous translocation of nanotubes through a lipid bilayer even for low membrane tensions. A specially designed microfluidic device allows us to trace the kinetic pathway of the translocation process and establish the threshold cholesterol concentration of 20% for translocation. The reported nanoscale cholesterol-induced membrane restructuring near the ultrashort CNT in lipid membranes enables precise control and specific targeting of a membrane using cholesterol. As an example, it may allow for specific targeting between cholesterol-rich mammalian cells and cholesterol-poor bacterial cells.

Identification and partial purification of thuricin 4AJ1 produced by Bacillus thuringiensis.

Thuricin 4AJ1, produced by Bacillus thuringiensis strain 4AJ1, showed inhibition activity against Bacillus cereus 0938 and ATCC 10987. It began to appear in the stationary phase and reached its maximum activity level of 209.958 U at 18 h against B. cereus 0938 and 285.689 U at 24 h against B. cereus ATCC 10987. Tricine-SDS-PAGE results showed that the partly purified thuricin 4AJ1 was about 6.5 kDa. The molecular weights of the known B. thuringiensis bacteriocins and the ones obtained by the two mainstream websites for predicting bacteriocins were inconsistent with the size of the thuricin 4AJ1, indicating that the bacteriocin obtained in this study may have a novel structure. Based on the biochemical properties, the thuricin 4AJ1 activities increased after treatment with proteinase K and lipase II, and were not affected by a-amylase, catalase, α-chymotrypsin VII and α-chymotrypsin II. It was heat tolerant, being active up to 90º C. In the pH 3-10 range, it maintained most of its activity. Finally, the sensitivity of the strain 4AJ1 to commonly used antibiotics was tested. In view of its stability and antibacterial activity, thuricin 4AJ1 may be applied as a food biopreservative.

Tension-Induced Translocation of an Ultrashort Carbon Nanotube through a Phospholipid Bilayer.

Increasing awareness of bioeffects and toxicity of nanomaterials interacting with cells puts in focus the mechanisms by which nanomaterials can cross lipid membranes. Apart from well-discussed energy-dependent endocytosis for large objects and passive diffusion through membranes by solute molecules, other translocation mechanisms based on physical principles can exist. We show the importance of membrane tension on the translocation through lipid bilayers of ultrashort carbon nanotubes (USCNTs). By using a combination of a microfluidic setup and single chain mean field (SCMF) theory, we observed that, under membrane tension, USCNT inserted into a lipid bilayer may spontaneously nucleate an unstable local pore, allowing it to escape from the bilayer. We demonstrated that stretching of the membrane is essential for triggering this mechanism of translocation, and no translocation is observed at low membrane tension. For this purpose, a quantitative analysis of the kinetic pathway associated with USCNT translocation induced by tension was performed in a specially designed microfluidic device, simultaneously combining optical fluorescence microscopy and electrophysiological measurements. An important outcome of these findings is the identification of the way to control the nanomaterial translocation through the lipid bilayer by membrane tension that can be useful in many practical applications.

Bactericidal activity of self-assembled palmitic and stearic fatty acid crystals on highly ordered pyrolytic graphite.

The wings of insects such as cicadas and dragonflies have been found to possess nanostructure arrays that are assembled from fatty acids. These arrays can physically interact with the bacterial cell membranes, leading to the death of the cell. Such mechanobactericidal surfaces are of significant interest, as they can kill bacteria without the need for antibacterial chemicals. Here, we report on the bactericidal effect of two of the main lipid components of the insect wing epicuticle, palmitic (C16) and stearic (C18) fatty acids. Films of these fatty acids were re-crystallised on the surface of highly ordered pyrolytic graphite. It appeared that the presence of two additional CH2 groups in the alkyl chain resulted in the formation of different surface structures. Scanning electron microscopy and atomic force microscopy showed that the palmitic acid microcrystallites were more asymmetric than those of the stearic acid, where the palmitic acid microcrystallites were observed to be an angular abutment in the scanning electron micrographs. The principal differences between the two types of long-chain saturated fatty acid crystallites were the larger density of peaks in the upper contact plane of the palmitic acid crystallites, as well as their greater proportion of asymmetrical shapes, in comparison to that of the stearic acid film. These two parameters might contribute to higher bactericidal activity on surfaces derived from palmitic acid. Both the palmitic and stearic acid crystallite surfaces displayed activity against Gram-negative, rod-shaped Pseudomonas aeruginosa and Gram-positive, spherical Staphylococcus aureus cells. These microcrystallite interfaces might be a useful tool in the fabrication of effective bactericidal nanocoatings. STATEMENT OF SIGNIFICANCE: Nanostructured cicada and dragonfly wing surfaces have been discovered to be able physically kill bacterial cells. Here, we report on the successful fabrication of bactericidal three-dimensional structures of two main lipid components of the epicuticle of insect wings, palmitic (C16) and stearic (C18) acids. After crystallisation onto highly ordered pyrolytic graphite, both the palmitic and stearic acid films displayed bactericidal activity against both Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus cells. The simplicity of the production of these microcrystallite interfaces suggests that a fabrication technique, based on solution deposition, could be an effective technique for the application of bactericidal nanocoatings.

Apatite nanoparticles strongly improve red blood cell cryopreservation by mediating trehalose delivery via enhanced membrane permeation.

Cryopreservation of red blood cells (RBC) is an important method for maintaining an inventory of rare RBC units and managing special transfusion circumstances. Currently, in a clinical setting, glycerol is used as cryoprotectant against freezing damage. After thawing and before transfusion, glycerol must however be removed to avoid intravascular hemolysis, via a complex and time-consuming deglycerolization process which requires specialized equipment. Improved cryopreservation methods using non-toxic agents are required to increase biocompatibility and decrease processing time. Biocompatible cryoprotectants (e.g. trehalose) were proposed, but their low permeation through RBC membranes limits their cryoprotection efficacy. Herein, we report for the first time a glycerol-free cryopreservation approach, using colloidal bioinspired apatite nanoparticles (NP) as bioactive promoters of RBC cryopreservation mediated by trehalose. Addition of apatite NP in the medium tremendously increases RBC cryosurvival, up to 91% (42% improvement compared to a control without NP) which is comparable to FDA-approved cryoprotection protocol employing glycerol. NP concentration and incubation conditions strongly modulate the NP bioactivity. Complementary experimental and computational analyses of the interaction between apatite NP and model lipid bilayers revealed complex events occurring at the NP-bilayer interface. Apatite NP do not cross the bilayer but momentarily modulate its physical status. These changes affect the membrane behavior, and promote the permeation of trehalose and a model fluorescent molecule (FITC). This approach is a new alternative to using toxic glycerol for cells cryopreservation, and the identification of this enhancing no-pore permeation mechanism of apatite NP appears as an original delivery pathway for cryoprotectant agents and beyond.