Arid1a regulates cell cycle exit of transit-amplifying cells by inhibiting the Aurka-Cdk1 axis in mouse incisor.

Stem cells self-renew or give rise to transit-amplifying cells (TACs) that differentiate into specific functional cell types. The fate determination of stem cells to TACs and their transition to fully differentiated progeny is precisely regulated to maintain tissue homeostasis. Arid1a, a core component of the switch/sucrose nonfermentable complex, performs epigenetic regulation of stage- and tissue-specific genes that is indispensable for stem cell homeostasis and differentiation. However, the functional mechanism of Arid1a in the fate commitment of mesenchymal stem cells (MSCs) and their progeny is not clear. Using the continuously growing adult mouse incisor model, we show that Arid1a maintains tissue homeostasis through limiting proliferation, promoting cell cycle exit and differentiation of TACs by inhibiting the Aurka-Cdk1 axis. Loss of Arid1a overactivates the Aurka-Cdk1 axis, leading to expansion of the mitotic TAC population but compromising their differentiation ability. Furthermore, the defective homeostasis after loss of Arid1a ultimately leads to reduction of the MSC population. These findings reveal the functional significance of Arid1a in regulating the fate of TACs and their interaction with MSCs to maintain tissue homeostasis.

Polymer Physics behind the Gel-Spinning of UHMWPE Fibers.

Gel-spinning of ultra-high molecular weight polyethylene (UHMWPE) fibers has attracted great interest in academia and industry since its birth and commercialization in the 1980s, due to unique properties such as high modulus, low density, and excellent chemical resistance. However, the high viscosity and long relaxation time greatly complicate processing. In industry, solvents, like decalin and paraffin oil, usually disentangle the physical networks and promote final drawability. From extruding the polymer solution to post-solid-stretching, many polymer physics problems that accompany high-modulus fiber gel-spinning should be understood and addressed. In this review, by detailed discussions about the effect of entanglements and intracrystalline chain dynamics on the mechanical properties of UHMWPE, theoretical descriptions of the structure formation of disentangled UHMWPE crystals, and the origin of high modulus and strength of final fibers are provided. Several physical intrinsic key factors are also discussed, revealing why UHMWPE is an ideal material for producing high-performance fibers.

Carboxybetaine-Based Zwitterionic Polymer Nanogels with Long Blood Circulation for Cancer Therapy.

Given the advantages of antifouling capacity and good biocompatibility, zwitterionic polymers have been profoundly applied for drug delivery to improve the pharmacokinetics profile. Here, a zwitterionic polymer (poly (carboxybetaine methacrylate) (PCBMA)) nanogel was fabricated by one-step reflux precipitation polymerization for doxorubicin (DOX) loading. The obtained nanogels display favorable long blood circulation without priming immune responses as a result of the introduction of the zwitterionic group. Meanwhile, the disulfide bonds deriving from the crosslinker endow nanogels with excellent glutathione-responsive degradation and sufficient drug release under a reduction environment. The carboxylate groups originating from carboxybetaine provide modification sites to conjugate with fluorescent dye to achieve labeling and biodistribution tracking. Overall, under the significantly prolonging circulation and enhanced tumor accumulation through passive targeting, DOX-loaded PCBMA nanogels show a noticeable tumor inhibition effect in mouse colorectal cancer models, which may provide a delivery vehicle with great promise in cancer therapy.

Biomimetic Robust All-Polymer Porous Coatings for Passive Daytime Radiative Cooling.

Passive daytime radiation cooling (PDRC) has gained considerable attention as an emerging and promising cooling technology. Polymer-based porous materials are one of the important candidates for PDRC application due to their easy processing, free of inorganic particle doping, and multifunctionality. However, the mechanical properties of these porous materials, which are critical in outdoor services, have been overlooked in previous studies. Herein, a nonsolvent-induced phase separation (NIPS) method combined with ambient pressure drying to prepare polyethylene-polysilicate all-polymer porous coatings is developed. The coatings possess a Cyphochilus beetle-like skeleton structure with optimal skeleton size, laminated anisotropy, and high volume fraction (64 ± 1%). These structure features ensure a maximum skeleton density without optical crowding, thus enhancing light scattering and stress dispersion, and balancing optical and mechanical properties. The coatings exhibit significant mechanical robustness (only ≈70 µm thickness reduction after 1000 Taber abrasion cycles at a 750 g load without influencing optical performance), durability, optical properties (a solar reflectance of ≈95% and an average near-normal thermal emittance of ≈96%), and PDRC performance (realizing sub-ambient cooling of ≈3-6 °C at midday with different weather conditions). The work provides a new solution to improve the practicability of polymer-based porous coatings in PDRC outdoor services and other fields.

Comparative analysis of serum and saliva samples using Raman spectroscopy: a high-throughput investigation in patients with polycystic ovary syndrome and periodontitis.

BACKGROUND: Polycystic ovary syndrome (PCOS) and periodontitis significantly affect women's oral and systemic health worldwide, and yet increase the risk of cardiovascular-metabolic diseases like diabetes and coronary heart disease. Regarding the PCOS-periodontitis connection, whether sex hormones, metabolic and inflammatory mediators could account for the underlying linking mechanism needs to be further investigated. This case-control study evaluated the hormonal, metabolic and inflammatory profiles in PCOS and non-PCOS subjects with various periodontal conditions, via assessing serum and saliva samples by Raman spectroscopy. METHODS: A total of 66 females with PCOS and 22 systemically healthy female volunteers were recruited in a single hospital. Full-mouth periodontal examination was undertaken for identifying the subjects with periodontal health, gingivitis or periodontitis. The datasets of sex hormones and metabolic indicators were retrieved from the hospital information system. Both serum and saliva samples were collected for detecting inflammatory mediators and Raman spectroscopic assessment. The subjects were categorized into four groups according to their conditions of PCOS and periodontitis for Raman spectroscopic analysis. Partial least squares discriminant analysis was performed to examine the inter-group differences in Raman spectra. RESULTS: PCOS patients exhibited greater mean probing depth (P < 0.05) and higher serum levels of triglycerides (P < 0.05) and matrix metalloproteinase-8 (P < 0.05) than those in non-PCOS participants. Both probing depth and triglyceride level were positively correlated with PCOS (P < 0.05). There was a significant difference in mean Raman spectra of saliva samples among the four groups with different conditions of PCOS and periodontitis (P < 0.05), while no significant inter-group difference existed in serum samples. CONCLUSIONS: The present study shows that periodontal condition may affect the biomolecular profiles of Raman spectra in serum and saliva of PCOS patients. It underscores the importance of the collaborative teamwork of dentists and gynecologists for enhancing women's oral health, general wellbeing and quality of life.

Surface functionalization-dependent inflammatory potential of polystyrene nanoplastics through the activation of MAPK/ NF-κB signaling pathways in macrophage Raw 264.7.

Increasing amounts of nanoplastics (NPs) in the environment are a great threat to human health, causing intestinal inflammation when consumed through seafood and water. There is, however, still a lack of understanding of the immunomodulatory role of NPs in immune cells, especially the early signal events behind inflammation resulting from NPs ingestion. In this study, we explored the dynamic internalization of polystyrene NPs and their carboxy and amino-functionalized products (PS, PS-COOH and PS-NH2) followed by activation of ROS-MAPK/NF-κB signaling pathways in macrophage RAW 264.7. The inflammatory and cytotoxic potentials of NPs were evaluated by ELISA and apoptosis assays. Results showed that PS-COOH accumulated most in cells and induced more pronounced ROS and apoptosis than PS, PS-NH2 and PS-µm. PS-COOH and PS-NH2 showed stronger MAPK/NF-κB activation potential to at a low concentration of 10 µg/mL than unmodified PS, followed by production of IL-6 and TNF-α cytokines. Furthermore, PS-COOH induced MAPK/NF-κB activation and cytokine secretion could be inhibited by NAC, indicating that ROS was responsible for signal dysregulation and immunogenicity of PS-COOH, but not for PS-NH2. The results suggested that the MAPK and NF-κB pathways were involved in NPs-induced macrophage inflammation, which was influenced by surface functionalization of NPs, with carboxylated PS NPs exhibiting a greater pro-inflammatory and cytotoxic potential.

Original and liposome-modified indocyanine green-assisted fluorescence study with animal models.

Medical diagnosis heavily relies on the use of bio-imaging techniques. One such technique is the use of ICG-based biological sensors for fluorescence imaging. In this study, we aimed to improve the fluorescence signals of ICG-based biological sensors by incorporating liposome-modified ICG. The results from dynamic light scattering and transmission electron microscopy showed that MLM-ICG was successfully fabricated with a liposome diameter of 100-300 nm. Fluorescence spectroscopy showed that MLM-ICG had the best properties among the three samples (Blank ICG, LM-ICG, and MLM-ICG), as samples immersed in MLM-ICG solution achieved the highest fluorescence intensity. The NIR camera imaging also showed a similar result. For the rat model, the best period for fluorescence tests was between 10 min and 4 h, where most organs reached their maximum fluorescence intensity except for the liver, which continued to rise. After 24 h, ICG was excreted from the rat's body. The study also analyzed the spectra properties of different rat organs, including peak intensity, peak wavelength, and FWHM. In conclusion, the use of liposome-modified ICG provides a safe and optimized optical agent, which is more stable and efficient than non-modified ICG. Incorporating liposome-modified ICG in fluorescence spectroscopy could be an effective way to develop novel biosensors for disease diagnosis.

Quantification of Giant Unilamellar Vesicle Fusion Products by High-Throughput Image Analysis.

Artificial cells are based on dynamic compartmentalized systems. Thus, remodeling of membrane-bound systems, such as giant unilamellar vesicles, is finding applications beyond biological studies, to engineer cell-mimicking structures. Giant unilamellar vesicle fusion is rapidly becoming an essential experimental step as artificial cells gain prominence in synthetic biology. Several techniques have been developed to accomplish this step, with varying efficiency and selectivity. To date, characterization of vesicle fusion has relied on small samples of giant vesicles, examined either manually or by fluorometric assays on suspensions of small and large unilamellar vesicles. Automation of the detection and characterization of fusion products is now necessary for the screening and optimization of these fusion protocols. To this end, we implemented a fusion assay based on fluorophore colocalization on the membranes and in the lumen of vesicles. Fluorescence colocalization was evaluated within single compartments by image segmentation with minimal user input, allowing the application of the technique to high-throughput screenings. After detection, statistical information on vesicle fluorescence and morphological properties can be summarized and visualized, assessing lipid and content transfer for each object by the correlation coefficient of different fluorescence channels. Using this tool, we report and characterize the unexpected fusogenic activity of sodium chloride on phosphatidylcholine giant vesicles. Lipid transfer in most of the vesicles could be detected after 20 h of incubation, while content exchange only occurred with additional stimuli in around 8% of vesicles.

Odontohypophosphatasia caused by a novel combination of two heterozygous variants: a case report.

Hypophosphatasia (HPP) is a rare genetic disorder mainly characterized by skeletal dysplasia that results from a deficiency in tissue-nonspecific alkaline phosphatase (TNSALP), which is encoded by the alkaline phosphatase (ALPL) gene. Odontohypophosphatasia (odonto-HPP) is a mild form of HPP characterized by oral symptoms, such as premature loss of primary teeth. This study was to describe a 4-year-old boy with premature loss of primary teeth who was diagnosed with odonto-HPP. X-ray radiography and laboratory examinations were performed for the diagnosis. Genetic etiology was revealed by whole-exome sequencing. A novel combination of two variants in the ALPL gene was identified in this case; this combination resulted in the odonto-HPP phenotype. c.346G>A (p.Ala116Thr) was inherited from the proband's father, whereas c.1563C>G (p.Ser521Arg) was inherited from the proband's mother. The proband's 8-year-old sister was a heterozygous carrier of c.346G>A (p.Ala116Thr) in the ALPL gene. Thus far, the proband's sister has been asymptomatic. Our findings indicate that c.346G>A is a pathogenic genetic alteration; c.1563C>G might cause a predisposition to the dental phenotype in combination with c.346G>A. It is important for pediatric dentists to consider a diagnosis of odonto-HPP in children with premature loss of primary teeth.

Stemness maintenance of stem cells derived from human exfoliated deciduous teeth (SHED) in 3D spheroid formation through the TGF-ß/Smad signaling pathway.

Mesenchymal stem cells (MSCs) have shown great potential as important therapeutic tools for dental pulp tissue engineering, with the maintenance and enhancement of their stemness being crucial for successful therapeutic application in vivo and three-dimensional (3D) spheroid formation considered a reliable technique for enhancing their pluripotency. Human exfoliated deciduous tooth stem cells (SHED) were cultured in a low attachment plate to form aggregates for five days. Then, the resulting spheroids were analyzed for pluripotent marker expression, paracrine secretory function, proliferation, signaling pathways involved, and distribution of key proteins within the spheroids. The results indicated that 3D spheroid formation significantly increased the activation of the transforming growth factor beta (TGF-ß)/Smad signaling pathway and upregulated the secretion and mRNA expression levels of TGF-ß, which in turn enhanced the expression of pluripotency markers in SHED spheroids. The activation of the TGF-ß/Smad signaling pathway through 3D spheroid formation was found to preserve the stemness properties of SHED. Thus, understanding the mechanisms behind pluripotency maintenance of SHED culture through 3D spheroid formation could have implications for the therapeutic application of MSCs in regenerative medicine and tissue engineering.

Low-Cost, High-Strength Cellulose-based Quasi-Solid Polymer Electrolyte for Solid-State Lithium-Metal Batteries.

Solid-state lithium-metal batteries are considered as the next generation of high-energy-density batteries. However, their solid electrolytes suffer from low ionic conductivity, poor interface performance, and high production costs, restricting their commercial application. Herein, a low-cost cellulose acetate-based quasi-solid composite polymer electrolyte (C-CLA QPE) was developed with a high Li+ transference number ( t L i + ${{t}_{{{\rm L}{\rm i}}^{+}}}$ ) of 0.85 and excellent interface stability. The prepared LiFePO4 (LFP)|C-CLA QPE|Li batteries exhibited excellent cycle performance with a capacity retention of 97.7 % after 1200 cycles at 1 C and 25 °C. The experimental results and Density Function Theory (DFT) simulation revealed that the partially esterified side groups in the CLA matrix contribute to the migration of Li+ and enhance electrochemical stability. This work provides a promising strategy for fabricating cost-effective, stable polymer electrolytes for solid-state lithium batteries.

Meta-Apo improves accuracy of 16S-amplicon-based prediction of microbiome function.

BACKGROUND: Due to their much lower costs in experiment and computation than metagenomic whole-genome sequencing (WGS), 16S rRNA gene amplicons have been widely used for predicting the functional profiles of microbiome, via software tools such as PICRUSt 2. However, due to the potential PCR bias and gene profile variation among phylogenetically related genomes, functional profiles predicted from 16S amplicons may deviate from WGS-derived ones, resulting in misleading results. RESULTS: Here we present Meta-Apo, which greatly reduces or even eliminates such deviation, thus deduces much more consistent diversity patterns between the two approaches. Tests of Meta-Apo on > 5000 16S-rRNA amplicon human microbiome samples from 4 body sites showed the deviation between the two strategies is significantly reduced by using only 15 WGS-amplicon training sample pairs. Moreover, Meta-Apo enables cross-platform functional comparison between WGS and amplicon samples, thus greatly improve 16S-based microbiome diagnosis, e.g. accuracy of gingivitis diagnosis via 16S-derived functional profiles was elevated from 65 to 95% by WGS-based classification. Therefore, with the low cost of 16S-amplicon sequencing, Meta-Apo can produce a reliable, high-resolution view of microbiome function equivalent to that offered by shotgun WGS. CONCLUSIONS: This suggests that large-scale, function-oriented microbiome sequencing projects can probably benefit from the lower cost of 16S-amplicon strategy, without sacrificing the precision in functional reconstruction that otherwise requires WGS. An optimized C++ implementation of Meta-Apo is available on GitHub ( https://github.com/qibebt-bioinfo/meta-apo ) under a GNU GPL license. It takes the functional profiles of a few paired WGS:16S-amplicon samples as training, and outputs the calibrated functional profiles for the much larger number of 16S-amplicon samples.

A randomized, controlled comparison of a stannous-containing dentifrice for reducing gingival bleeding and balancing the oral microbiome relative to a positive control.

PURPOSE: To evaluate the effect of a stannous-containing fluoride dentifrice on gingival health and on the composition of the oral microbiome versus a positive control dentifrice over 2 weeks, in a population of healthy adults with self-reported sub-optimal oral health at baseline. METHODS: This was a randomized, controlled, double-blind clinical study. 87 subjects with self-reported sub-optimal oral health at enrollment were randomized to brush twice daily with either an experimental dentifrice (n= 43) or a marketed positive control dentifrice (n= 43), both containing stannous chloride and 0.321% sodium fluoride. All subjects used a soft, manual toothbrush that was provided. The Mazza modification of gingival papillary bleeding Index (Mazza GI) was used to assess gingivitis at baseline and at Week 2. Supragingival plaque was collected for microbiome composition analyses at baseline, Week 1, and Week 2. RESULTS: 83 subjects completed the study. Baseline means were balanced between the treatment groups (P> 0.34). At Week 2, the positive control dentifrice demonstrated a 63.8% statistically significant (P< 0.0001) reduction relative to baseline for Mazza number of gingival bleeding sites. The experimental stannous containing dentifrice provided a comparable 63.5% gingival bleeding reduction versus baseline. There was no significant (P= 0.96) difference between the two dentifrices for either Mazza GI score or number of bleeding sites measured. The microbiome composition analysis at Week 1 found that 28 gingivitis-associated bacterial genera, including Porphyromonas, Tannerella, and Fusobacterium, were significantly inhibited in both dentifrice groups when compared to baseline, while the relative abundance of genera associated with oral health, such as Rothia, Streptococcus, Haemophilus, and Lautropia, was significantly elevated after treatment. These improvements in the oral ecosystem were sustained at Week 2. CLINICAL SIGNIFICANCE: An experimental stannous-containing sodium fluoride dentifrice significantly reduced gingival bleeding comparable to a positive control, and both dentifrices promoted a shift in the oral microbiome towards those genera associated with oral health in a subject population with self-reported sub-optimal oral health at baseline.

BMP signaling orchestrates a transcriptional network to control the fate of mesenchymal stem cells in mice.

Signaling pathways are used reiteratively in different developmental processes yet produce distinct cell fates through specific downstream transcription factors. In this study, we used tooth root development as a model with which to investigate how the BMP signaling pathway regulates transcriptional complexes to direct the fate determination of multipotent mesenchymal stem cells (MSCs). We first identified the MSC population supporting mouse molar root growth as Gli1+ cells. Using a Gli1-driven Cre-mediated recombination system, our results provide the first in vivo evidence that BMP signaling activity is required for the odontogenic differentiation of MSCs. Specifically, we identified the transcription factors Pax9, Klf4, Satb2 and Lhx8 as being downstream of BMP signaling and expressed in a spatially restricted pattern that is potentially involved in determining distinct cellular identities within the dental mesenchyme. Finally, we found that overactivation of one key transcription factor, Klf4, which is associated with the odontogenic region, promotes odontogenic differentiation of MSCs. Collectively, our results demonstrate the functional significance of BMP signaling in regulating MSC fate during root development and shed light on how BMP signaling can achieve functional specificity in regulating diverse organ development.

Beltrania sinensis sp. nov., an endophytic fungus from China and a key to species of the genus.

During a survey of endophytic fungi in plant roots in secondary forests in Yunnan, China, a novel ascomyceteous taxon, Beltrania sinensis, was isolated from Quercus cocciferoides Hand.-Mazz. and Fraxinus malacophylla Hemsl. This novel species is characterized by having oval or obovoid conidiogenous cells with several apical, flat-tipped denticles, and biconic, aseptate, smooth, pale brown conidia with a hyaline to subhyaline equatorial transverse band and apical tubular appendage. Phylogenetic analysis of the combined sequences of the internal transcribed spacer and the LSU rRNA gene confirmed its novel species status within the genus Beltrania. Here, the novel species is described and illustrated, and a taxonomic key to species in the genus Beltrania is provided.

Constitutive activation of hedgehog signaling adversely affects epithelial cell fate during palatal fusion.

Cleft palate is one of the most common craniofacial congenital defects in humans. It is associated with multiple genetic and environmental risk factors, including mutations in the genes encoding signaling molecules in the sonic hedgehog (Shh) pathway, which are risk factors for cleft palate in both humans and mice. However, the function of Shh signaling in the palatal epithelium during palatal fusion remains largely unknown. Although components of the Shh pathway are localized in the palatal epithelium, specific inhibition of Shh signaling in palatal epithelium does not affect palatogenesis. We therefore utilized a hedgehog (Hh) signaling gain-of-function mouse model, K14-Cre;R26SmoM2, to uncover the role of Shh signaling in the palatal epithelium during palatal fusion. In this study, we discovered that constitutive activation of Hh signaling in the palatal epithelium results in submucous cleft palate and persistence of the medial edge epithelium (MEE). Further investigation revealed that precise downregulation of Shh signaling is required at a specific time point in the MEE during palatal fusion. Upregulation of Hh signaling in the palatal epithelium maintains the proliferation of MEE cells. This may be due to a dysfunctional p63/Irf6 regulatory loop. The resistance of MEE cells to apoptosis is likely conferred by enhancement of a cell adhesion network through the maintenance of p63 expression. Collectively, our data illustrate that persistent Hh signaling in the palatal epithelium contributes to the etiology and pathogenesis of submucous cleft palate through its interaction with a p63/Irf6-dependent biological regulatory loop and through a p63-induced cell adhesion network.

Preferential Tumor Accumulation of Polyglycerol Functionalized Nanodiamond Conjugated with Cyanine Dye Leading to Near-Infrared Fluorescence In Vivo Tumor Imaging.

Preferential accumulation of nanoparticles in a tumor is realized commonly by combined effects of active and passive targeting. However, passive targeting based on an enhanced permeation and retention (EPR) effect is not sufficient to observe clear tumor fluorescence images in most of the in vivo experiments using tumor-bearing mice. Herein, polyglycerol-functionalized nanodiamonds (ND-PG) conjugated with cyanine dye (Cy7) are synthesized and it is found that the resulting ND-PG-Cy7 is preferentially accumulated in the tumor, giving clear fluorescence in in vivo and ex vivo fluorescence images. One of the plausible reasons is the longer in vivo blood circulation time of ND-PG-Cy7 (half-life: 58 h determined by the pharmacokinetic analysis) than that of other nanoparticles (half-life: <20 h in most of the previous reports). In a typical example, the fluorescence intensity of tumors increases due to continuous tumor accumulation of ND-PG-Cy7, even more than one week postinjection. This may be owing to the stealth effect of PG that was reported previously, avoiding recognition and excretion by reticuloendothelial cells, which are abundant in liver and spleen. In fact, the fluorescence intensities from the liver and spleen is similar to those from other organs, while the tumor exhibits much stronger fluorescence in the ex vivo image.

A protocell with fusion and division.

A protocell is a synthetic form of cellular life that is constructed from phospholipid vesicles and used to understand the emergence of life from a nonliving chemical network. To be considered 'living', a protocell should be capable of self-proliferation, which includes successive growth and division processes. The growth of protocells can be achieved via vesicle fusion approaches. In this review, we provide a brief overview of recent research on the formation of a protocell, fusion and division processes of the protocell, and encapsulation of a defined chemical network such as the genetic material. We also provide some perspectives on the challenges and future developments of synthetic protocell research.

Characterization of a novel polyvinyl alcohol/chitosan porous hydrogel combined with bone marrow mesenchymal stem cells and its application in articular cartilage repair.

BACKGROUND: Different substances are combined to compensate for each other's drawbacks and create an appropriate biomaterial. A novel Polyvinyl alcohol (PVA)/chitosan (CS) porous hydrogel was designed and applied to the treatment of osteochondral defects. METHODS: Hydrogels of various PVA/CS ratios were tested for physiochemical and mechanical properties in addition to cytotoxicity and biocompatibility. The hydrogels with the best PVA/CS ratio were used in the animal study. Osteochondral defects were created at the articular cartilage of 18 rabbits. They were assigned to different groups randomly (n = 6 per group): the osteochondral defect only group (control group), the osteochondral defect treated with hydrogel group (HG group), and the osteochondral defect treated with hydrogel loaded with bone marrow mesenchymal stem cells (BMSCs) group (HG-BMSCs group). The cartilage was collected for macro-observation and histological evaluation at 12 weeks after surgery. RESULTS: The Hydrogel with PVA/CS ratio of 6:4 exhibited the best mechanical properties; it also showed stable physical and chemical properties with porosity and over 90% water content. Furthermore, it demonstrated no cytotoxicity and was able to promote cell proliferation. The HG-BMSCs group achieved the best cartilage healing. CONCLUSIONS: The novel PVA/CS porous composite hydrogel could be a good candidate for a tissue engineering material in cartilage repair.

A novel general and efficient technique for dissociating antigen in circulating immune complexes.

Circulating immune complexes (CICs) are produced during the immune response. It is more clinically important to establish a general and efficient CICs dissociation technique for the detection of antigens for CICs other than the detection of free antigens in the serum. Polyethylene glycol (PEG) two-precipitation separation and glycine-HCl as a buffer system were employed to develop a general and efficient buffer dissociation technique to separate CICs from serum and dissociate antigens from CICs. The measurement value of new PEG two-precipitation separation technique was higher than traditional PEG precipitation separation technique. There were slight differences in the dissociation conditions of HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC as compared to HBsAg-IC. The detection of antigens in HBsAg-IC, HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC with this technique was superior to that with HCl Dissociation, Trypsin Digestion or Immune Complex Transfer technique. PEG two-precipitation dissociation technique may reduce macromolecular protein and the adhesion of free antigens during the co-precipitation, which increases the efficiency of separation and precipitation of CICs. This technique also avoids the damage of reagents to antigens, assuring the repeatability, reliability and validity. Thus, this technique is application in samples negative or positive for free antigens.