Clostridium perfringens gas gangrene caused by closed abdominal injury: A case report and review of the literature.

BACKGROUND: Abdominal Clostridium perfringens (C. perfringens) gas gangrene is a rare infection that has been described in the literature as most frequently occurring in postoperative patients with open trauma. Intra-abdominal gas gangrene caused by C. perfringens infection after closed abdominal injury is extremely rare, difficult to diagnose, and progresses rapidly with high mortality risk. Here, we report a case of C. perfringens infection caused by closed abdominal injury. CASE SUMMARY: A 54-year-old male suffered multiple intestinal tears and necrosis after sustaining an injury caused by falling from a high height. These injuries and the subsequent necrosis resulted in intra-abdominal C. perfringens infection. In the first operation, we removed the necrotic intestinal segment, kept the abdomen open and covered the intestine with a Bogota bag. A vacuum sealing drainage system was used to cover the outer layer of the Bogota bag, and the drainage was flushed under negative pressure. The patient was transferred to the intensive care unit for supportive care and empirical antibiotic treatment. The antibiotics were not changed until the results of bacterial culture and drug susceptibility testing were obtained. Two consecutive operations were then performed due to secondary intestinal necrosis. After three definitive operations, the patient successfully survived the perioperative period. Unfortunately, he died of complications related to Guillain-Barre syndrome 75 d after the first surgery. This paper presents this case of intra-abdominal gas gangrene infection and analyzes the diagnosis and treatment based on a review of current literature. CONCLUSION: When the intestines rupture leading to contamination of the abdominal cavity by intestinal contents, C. perfringens bacteria normally present in the intestinal tract may proliferate in large numbers and lead to intra-abdominal infection. Prompt surgical intervention, adequate drainage, appropriate antibiotic therapy, and intensive supportive care comprise the most effective treatment strategy. If the abdominal cavity is heavily contaminated, an open abdominal approach may be a beneficial treatment.

Integrated analysis of the genomic and transcriptional profile of gliomas with isocitrate dehydrogenase-1 and tumor protein 53 mutations.

Background: The gene mutation of isocitrate dehydrogenase-1 (IDH1) is commonly found in LGG and some GBM patients and usually carries tumor protein 53 (TP53) mutations. However, the underlying mechanisms on both mutations of glioma patients in IDH1 and TP53 are still unclear. Aim: To find the potential target markers in GBM and LGG patients with IDH1 and TP53 mutation.Method: A total of 1122 glioma patients from The Cancer Genome Atlas were enrolled and divided as wild-type (without IDH1 and TP53 mutations) or both mutant (both IDH1 and TP53 mutations). The data of clinicopathological characteristics, mRNA, mutations, and copy number alteration were analyzed. Results: IDH1 and TP53 mutations, not gene expression, affect the survival probability of GBM and LGG patients, which might be related to neuron function, immune function, tumor invasion, and metastasis. The effects of the selected gene (EMILIN3, SAA1, VSTM2A, HAMP, IFT80, and CHIC2) on glioma patients could be regulated by IDH1 and TP53 mutations and had a higher survival possibility in these patients. Conclusions: The selected genes in GBM and LGG patients with IDH1 and TP53 mutations could be a potential prognosis marker in the future.

Bubble-Liquid Membrane Method for Preparing Spherical Calcium Carbonate Nanoparticles.

In this work, we describe the principle and operation of a bubble-liquid membrane reactor, and use of the reactor to prepare spherical calcium carbonate nanoparticles. The products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and laser particle size analysis. The effects of additives to control crystal morphology, coating agents, and the stirring speed of the bubble-liquid membrane reactor were investigated. Spherical calcium carbonate nanoparticles with uniform dispersion and no agglomeration were obtained when a disodium hydrogen phosphate/ethylenediaminetetraacetic acid disodium salt mixture (1:1 mass ratio) was used as the additive, oleic acid was used as the coating agent (1.5 wt%), and the stirring speed was 5000-6000 r/min. The results indicate that the bubble-liquid membrane reactor may be suitable for continuous industrial production of calcium carbonate nanoparticles.

Research progress of berberine mediated photodynamic therapy.

Berberine (BBR) is a plant secondary metabolite that has been used in photodynamic therapy (PDT) in the last few decades. The present review aimed to discuss the research progress of BBR-mediated photodynamic actions. The following key words were searched in several databases: 'Berberine' combined with 'photodynamic therapy', 'sonodynamic therapy (SDT)', 'ultraviolet', 'reactive oxygen' and 'singlet oxygen'. The results demonstrated that both type I and type II reactions participated in the photodynamic progression of BBR derivatives. In addition, the photochemical characteristics of BBR derivatives were affected by the polarity, pH and O2 content of solvents. DNA binding increases the lifespan of the photoexcited BBR state and generation of singlet oxygen (1O2). The chemical properties of substituents in different positions of the BBR skeleton are pivotal for its photochemical properties, particularly the methylenedioxy group at the C-2 and C-3 positions. BBR is a promising agent for mediating both PDT- and SDT-treated diseases, particularly in tumors. However, further studies are required to validate their biological effects. In addition, the molecular mechanisms underlying the antitumor effects of BBR-PDT remain unclear and warrant further investigation. The structural modification and targeted delivery of BBR have made it possible to broaden its applications; however, experimental verification is required. Overall, BBR acts as a sensitizer for PDT and has promising development prospects.

Clinical characteristics and impacts of traditional Chinese medicine treatment on the convalescents of COVID-19.

Objectives: A significant proportion of discharged COVID-19 patients still have some symptoms. Traditional Chinese medicine (TCM) has played an important role in the treatment of COVID-19, but whether it is helpful for discharged patients is still unknown. The aim of this study was to retrospectively analyze the impacts of TCM treatment on the convalescents of COVID-19. Methods: A total of 372 COVID-19 convalescents from February 21 to May 3 in Shenzhen, China were retrospectively analyzed, 291 of them accepted clinically examined at least once and 191 convalescents accepted TCM. Results: After retrospective analysis of the clinical data of convalescents accepted TCM treatment or not, we found that the white blood cell count, as well as serum interleukin-6 and procalcitonin decreased in TCM group. Serum γ-glutamyl transpeptidase was significantly decreased, while prealbumin and albumin increased in TCM group. Red blood cell, hemoglobin, and platelet count increased in TCM group. The mechanisms of TCM treatment might be the overall regulations, including balanced immune response, improved hematopoiesis and coagulation systems, enhanced functions of liver and heart, increased nutrient intake and lipid metabolism. Conclusions: This study suggested that TCM treatment would be beneficial for discharged COVID-19 patients. However, long-term medical observation and further study with randomized trial should be done to confirm this result. Besides, the potential molecular mechanisms of TCM treatment should be further revealed.

Liver function recovery of COVID-19 patients after discharge, a follow-up study.

Objective: The aim of this study was to observe the liver function recovery of COVID-19 patients after discharge. Patients and Methods: A total of 253 discharged COVID-19 patients in Shenzhen city, China were selected. The clinical characteristics of these patients were assessed. A 2-month follow-up and laboratory hematology test were performed to examine the status of patients' liver function. Results: Patients combined with liver diseases, especially fatty liver, are more likely to progress to severe condition (P<0.05). Patients in severe condition and those with liver diseases have higher rates of liver injuries during hospitalization, characterized by a significant increase in alanine aminotransferase (ALT) and aspartate aminotransferase (AST, P<0.01). The ALT, AST/ALT, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), total protein (TP), albumin (ALB), and A/G levels showed significant differences in comparison with the control group (P<0.05, and P<0.001); and the outlier ratio of A/G, ALT, GGT and ALP of patients remained abnormal higher within 14 days after discharge (P<0.001). Liver injuries of COVID-19 patients may be related to the epidemiological characteristics, clinical indexes, basic diseases, symptoms, drug treatment during hospitalization and the complications. Indicators of liver function were correlated with cardiac function, renal function, thyroid function, lipid metabolism, glucose metabolism, immune index, leukocyte, erythrocyte, hemoglobin and platelet related indexes. The outlier ratio of TP, ALB and GLB remained extremely low throughout the follow-up period; the outlier ratio of ALT, AST and GGT decreased below 10% from a high level at 40 days after discharged. However, the outlier ratio of A/G, AST/ALT and ALP remained high during the follow-up period. Conclusions: Abnormal liver function might indicate worse recovery of COVID-19 patients. Changes in liver function should be emphasized during long-term follow-up of COVID-19 patients after hospital discharge; the necessity of employing appropriate interventions for liver function repair should be emphasized.

Clinical characteristics and follow-up analysis of 324 discharged COVID-19 patients in Shenzhen during the recovery period.

Objectives: Research on recovering COVID-19 patients could be helpful for containing the pandemic and developing vaccines, but we still do not know much about the clinical features, recovery process, and antibody reactions during the recovery period. Methods: We retrospectively analysed the epidemiological information, discharge summaries, and laboratory results of 324 patients. Results: In all, 15 (8.62%) patients experienced chest distress/breath shortness, where 8 of the 15 were severely ill. This means severely ill patients need an extended amount of time to recover after discharge; next, 20 (11.49%) patients experienced anxiety and 21 (12.07%) had headache/insomnia and a small fraction of them complained of anosmia/ageusia, indicating that these patients need treatment for mental and psychological health issues. Regarding the re-positive patients, their CT and laboratory test results showed no obvious evidence of illness progress or infectivity but a high anti-SARS-CoV-2 antibody expression. Conclusion: Recovered COVID-19 patients need psychological and physiological care and treatment, re-positivity can occur in any person, but juveniles, females, and patients with mild/moderate existing symptoms have higher rates of re-positivity, While there is no evidence that turning re-positive has an impact on their infectivity, but it still alerted us that we need differentiate them in the following managements.

Sinoporphyrin sodium is a promising sensitizer for photodynamic and sonodynamic therapy in glioma.

The aim of the present study was to explore the antitumor effects of sinoporphyrin sodium (DVDMS)­mediated photodynamic therapy (PDT) and sonodynamic therapy (SDT) in glioma, and to reveal the underlying mechanisms. The uptake of DVDMS by U­118 MG cells was detected by flow cytometry (FCM). A 630­nm semiconductor laser and 1­MHz ultrasound were used to perform PDT and SDT, respectively. Cell proliferation and apoptosis were evaluated using the Cell Counting Kit­8 assay, FCM and Hoechst 33258 staining, respectively. Western blot analysis was used to detect protein expression and phosphorylation levels. BALB/c nude mice were used to establish a xenograft model of U­118 MG cells. DVDMS was injected intravenously and PDT and SDT were performed 24 h later. An in vivo imaging system was used to evaluate the fluorescence of DVDMS, to measure tumor sizes, and to evaluate the therapeutic effects. The uptake of DVDMS by U­118 MG cells was optimal after 4 h. PDT and SDT following DVDMS injection significantly inhibited the proliferation and increased apoptosis of glioma cells in vitro (P<0.05, P<0.01) respectively. In vivo, the fluorescence intensity of DVDMS was lower in the PDT and SDT groups compared with the DVDMS group, while tumor cell proliferation and weight were lower in the PDT and SDT groups than in the control group (P<0.05, P<0.01). However, there was no significant difference when laser, ultrasound or DVDMS were applied individually, compared with the control group. Hematoxylin and eosin staining suggested that both PDT and SDT induced significant apoptosis and vascular obstruction in cancer tissues. DVDMS­mediated PDT and SDT inhibited the expression levels of proliferating cell nuclear antigen (PCNA) and Bcl­xL, increased cleaved ­caspase 3 levels, and decreased the protein phosphorylation of the PI3K/AKT/mTOR signaling pathway. Changes in the expression of PCNA, and Bcl­xL and in the levels of cleaved­caspase 3 were partly reversed by N­acetyl­L­cysteine, a reactive oxygen species (ROS) scavenger. Similar results were obtained with FCM. DVDMS­mediated PDT and SDT inhibited glioma cell proliferation and induced cell apoptosis in vitro and in vivo, potentially by increasing the generation of ROS and affecting protein expression and phosphorylation levels.

FBW7 protects against spinal cord injury by mitigating inflammation-associated neuronal apoptosis in mice.

Spinal cord injury (SCI) leads to severe and long-lasting neurological disability. Presently, the lack of effective therapies for SCI is largely attributable to an incomplete understanding of its pathogenesis. F-box and WD repeat domain-containing protein 7 (FBW7, also known as FBXW7) is a type of E3 ubiquitin ligase complex, and plays essential roles in regulating different pathological and physiological processes. In this study, we attempted to explore the effects of FBW7 on SCI progression by the in vivo and in vitro experiments. SCI mice showed significantly reduced expression of FBW7 in spinal cord tissues. Promoting FBW7 expression via intrathecal injection of AAV9/FBW7 effectively improved locomotor function in SCI mice. Neuronal death in spinal cords of SCI mice was obviously ameliorated by FBW7 over-expression, along with greatly decreased expression of cleaved Caspase-3. In addition, microglial activation in spinal cord specimens was detected in SCI mice through increasing Iba-1 expression levels, which was, however, attenuated in SCI mice injected with AAV9/FBW7. Additionally, FBW7 over-expression dramatically restrained inflammatory response in spinal cord tissues of SCI mice, as evidenced by the down-regulated expression of tumor necrosis factor-α (TNF-α) and interleukin 1ß (IL-1ß) through blocking the activation of nuclear factor-κB (NF-κB) signaling. These anti-inflammatory effects of FBW7 were confirmed in LPS-stimulated mouse microglial BV2 cells. Finally, our in vitro studies showed that conditional medium (CM) collected from LPS-incubated BV2 cells markedly induced apoptosis in the isolated primary spinal neurons; However, this effect was overtly ameliorated by CM from LPS-exposed BV2 cells over-expressing FBW7. Thus, FBW7-regulated inflammation in microglial cells was involved in the amelioration of neuronal apoptosis during SCI development. Collectively, these findings illustrated that FBW7 expression was down-regulated in spinal cords of SCI mice, and promoting its expression could effectively mitigate SCI progression by repressing microglial inflammation and neuronal death.

Recurrence of positive SARS-CoV-2 viral RNA in recovered COVID-19 patients during medical isolation observation.

Recently, the recurrence of positive SARS-CoV-2 viral RNA in recovered COVID-19 patients is receiving more attention. Herein we report a cohort study on the follow-up of 182 recovered patients under medical isolation observation. Twenty (10.99%) patients out of the 182 were detected to be SARS-CoV-2 RNA positive (re-positives), although none showed any clinical symptomatic recurrence, indicating that COVID-19 responds well to treatment. Patients aged under 18 years had higher re-positive rates than average, and none of the severely ill patients re-tested positive. There were no significant differences in sex between re-positives and non-re-positives. Notably, most of the re-positives turned negative in the following tests, and all of them carried antibodies against SARS-CoV-2. This indicates that they might not be infectious, although it is still important to perform regular SARS-CoV-2 RNA testing and follow-up for assessment of infectivity. The findings of this study provide information for improving the management of recovered patients, and for differentiating the follow-up of recovered patients with different risk levels.

[Nasal resorption of prim-O-glucosylcimifugin and 5-O-methylvisammioside in rats].

In this experiment, rat nasal mucosa absorption characteristics of prim-O-glucosylcimifugin and 5-O-methylvisammioside were studied to provide a basis for drug delivery of Toutongning nasal spray. The nasal mucosa absorption test in rats was conducted with in situ nasal perfusion method after pH 6 buffer solution was used to prepare high, medium and low concentrations of prim-O-glucosylcimifugin, 5-O-methylvisammioside mixed solution as liquid circulation in nasal cavity. Then the concentrations of the circulating liquid compositions to be measured were determined by HPLC, and the absorption rates of prim-O-glucosylcimifugin and 5-O-methylvisammioside under different pH conditions were also investigated. According to the results, the absorption rate constant was (0.588±0.041)×10⁻³, (0.547±0.023)×10⁻³, (0.592±0.063)×10⁻³ min⁻¹ for prim-O-glucosylcimifugin high, middle and low concentrations, and (0.438±0.041)×10⁻³, (0.407±0.023)×10⁻³, and (0.412±0.063)×10⁻³ min⁻¹ for 5-O-methylvisammioside high, middle and low concentrations. There was no significant difference among high, middle and low concentration groups, and the absorption under pH 6 was better than that under other pH conditions. Therefore, we can get the conclusion that the main active ingredient of Toutongning nasal sprays can be absorbed through the nasal mucosa, and it is feasible to make nasal spray; in addition, pH 6 of nasal spray is scientific and reasonable.

Calpain-Calcineurin-Nuclear Factor Signaling and the Development of Atrial Fibrillation in Patients with Valvular Heart Disease and Diabetes.

Calpain, calcineurin (CaN), and nuclear factor of activated T cell (NFAT) play a key role in the development of atrial fibrillation. Patients with valvular heart disease (VHD) are prone to develop atrial fibrillation (AF). Thus, our current study was aimed at investigating whether activation of calpain-CaN-NFAT pathway is associated with the incidence of AF in the patients with VHD and diabetes. The expressions of calpain 2 and alpha- and beta-isoforms of CaN catalytic subunit (CnA) as well as NFAT-c3 and NFAT-c4 were quantified by quantitative reverse transcription-polymerase chain reaction in atrial tissues from 77 hospitalized patients with VHD and diabetes. The relevant protein content was measured by Western blot and calpain 2 in human atrium was localized by immunohistochemistry. We found that the expressions of calpain 2, CnA alpha and CnA beta, and NFAT-c3 but not NFAT-c4 were significantly elevated in the samples from patients with AF compared to those with sinus rhythm (SR). Elevated protein levels of calpain 2 and CnA were observed in patients with AF, and so was the enhanced localization of calpain 2. We thereby concluded that CaN together with its upstream molecule, calpain 2, and its downstream effector, NFAT-c3, might contribute to the development of AF in patients with VHD and diabetes.

[Anti-tumor effect of brucine-loaded chitosan nanoparticles in vitro].

We designed two novel polymer materials N-glycyrrhetinic acid-polyethylene glycol-chitosan derivatives (NGPC) and N-quaternary ammonium-chitosan derivatives (NQC). We prepared three kinds of drug loaded chitosan nanoparticles (brucine/NGPC-NPs, brucine/NQC-NPs, brucine/MNPs) by ionic crosslinking method with brucine as a model drug and chitosan nanoparticles（brucine/NGPC-NPs, brucine/NQC-NPs） as the reference formulation. Using high content analysis, flow cytometry, immunofluorescence, transmission electron microscopy and other advanced technology, we tested the effect of 20 µg·mL(-1) concentration of brucine solution and brucine/ chitosan nanoparticles（brucine/CTS-NPs） in hepatocarcinoma (HEpG2) cells and evaluated the apoptosis induced by the treatment. The results suggested that brucine-CTS/NPs had a strongest activity in killing tumor cells, and increased the total cell apoptosis rate with a significant formation of "crescent-shaped" body, swelling mitochondria, mitochondria cristae missing, decreased mitochondrial membrane potential and release of cytochrome C. The activity was enhanced by multifunctional nanocomposite particles that increased the cumulative amount of drug in the mitochondria for the anti-tumor effect.

[Research on Biological Assessment for Panax notoginseng Quality on Real-time Cell Electronic Analysis].

OBJECTIVE: To establish the quality control and evaluation methods of Panax notoginseng on promoting blood circulation and removing blood stasis effects, by determining cell index to evaluate the quality of Panax notoginseng from different habitats. METHODS: Using the real-time cell electronic analysis technology (RTCA) to examine the biological activity of specific cell-dependent cell lines on Panax notoginseng extracts. Changing trends and laws of the samples within a certain time were analyzed, and the cell index at the optimum time was determined. RESULTS: In four batches of Panax notoginseng from different habitats, cell index of Panax notoginseng from Chuxiong of Yunnan Province at the optimal time of 38 h was the highest, and the biological activity was the strongest. Cell index of Panax notoginseng from Wenshan of Yunnan Province at the optimal time of 38 h cells was the lowest, and the biological activity was the weakest. CONCLUSION: The method based on the real-time cell electronic analysis technology can initially be used in the detection of biological activity of Panax notoginseng.

Controllable organization and high throughput production of recoverable 3D tumors using pneumatic microfluidics.

Three-dimensional tumor culture methods offer a high degree of biological and clinical relevance to in vitro models as well as cancer therapy. However, a straightforward, dynamic, and high-throughput method for micro-manipulation of 3D tumors is not yet well established. In this study, we present a novel and simple strategy for producing biomimetic 3D tumors in a controllable, high throughput manner based on an integrated microfluidic system with well-established pneumatic microstructures. Serial manipulations, including one-step cell localization, array-like self-assembly, and real-time analysis of 3D tumors, are accomplished smoothly in the microfluidic device. The recovery of tumor products from the chip is performed by dynamic off-switch of the pneumatic microstructures. In addition, this microfluidic platform is demonstrated to be capable of producing multiple types of 3D tumors and performing the evaluation of tumor targeting by nanomedicine. The pneumatic microfluidic-based 3D tumor production shows potential for research on tumor biology, tissue engineering, and drug delivery.

High throughput and multiplex localization of proteins and cells for in situ micropatterning using pneumatic microfluidics.

Micropatterning technologies are emerging as an enabling tool for various microfluidic-based applications in life sciences. However, the high throughput and multiplex localization of multiple bio-components in a microfluidic device has not yet been well established. In this paper, we describe a simple and in situ micropatterning method using an integrated microfluidic device with pneumatic microstructures (PµSs) for highly controllable immobilization of both proteins and cells in a high throughput, geometry-dynamic, and multi-patterning way. The precise Pluronic F127 passivation of a microchamber surface except the PµS-blocked regions was performed and characterized, and the spatial dynamics and consistency of both the PµSs and protein/cell micropatterning were optically evaluated and quantitatively demonstrated too. Furthermore, a systematic investigation of PµS-assisted micropatterning in microfluidics was carried out. The feature of high throughput and spatial control of micropatterning can be simply realized by using the well-designed PµS arrays. Meanwhile, the co-micropatterning of different proteins (bovine serum albumin and chicken egg albumin) and cells (human umbilical vein endothelial cells and human hepatocellular carcinoma cells) in a microfluidic device was successfully accomplished with the orderly serial manipulation of PµS groups. We demonstrate that PµS-assisted micropatterning can be applied as a convenient microfluidic component for large-scale and diversified protein/cell patterning and manipulation, which could be useful for cell-based tissue organization, high-throughput imaging, protein-related interactions and immunoassays.

Preparation and pharmacokinetics in beagle dogs of ganershu sustained-release pellets.

BACKGROUND: The active ingredients of Ganershu compound recipe, which are effective for hepatitis treatment in liver protection and transaminase reduction. However, the active ingredients of Ganershu compound recipe are poor absorption, which conduct it has a low oral bioavailability. OBJECTIVE: We prepared Ganershu sustained-release pellets (GSPs) by fluidized-bed on central composite design-response surface methodology and increase its bioavailability in beagle dogs. MATERIALS AND METHODS: In this study, GSPs were successfully prepared. The Drug-loaded pellets and sustained-release coated were carried out in fluidized-bed machine. GSP was optimized for fitting release, roundness, and the overall desirability by central composite design-response surface methodology. RESULTS: To optimize cumulative release profile, the outermost ethyl cellulose coating layer and the hydroxypropyl methyl cellulose (HPMC) swelling layer were employed, which were respectively given coating levels in terms of weight gain of 22% and 6%, the concentration of HPMC is 4.5% (g/ml). The pharmacokinetics of Ganershu normal pellets (GNPs) and GSP was studied in beagle dogs after oral administration. The naringenin as an index, the area under the curve0-∞ of naringenin in GSP was 1.38 times greater than that of GNP. Meanwhile, Tmax of GSP was prolonged for about 74%. CONCLUSION: This study can clearly indicate that we enhanced the oral bioavailability of Ganershu by preparing the GSP, which had the sustained dissolution and improved the potential of it for clinical application.

High-throughput rare cell separation from blood samples using steric hindrance and inertial microfluidics.

The presence and quantity of rare cells in the bloodstream of cancer patients provide a potentially accessible source for the early detection of invasive cancer and for monitoring the treatment of advanced diseases. The separation of rare cells from peripheral blood, as a "virtual and real-time liquid biopsy", is expected to replace conventional tissue biopsies of metastatic tumors for therapy guidance. However, technical obstacles, similar to looking for a needle in a haystack, have hindered the broad clinical utility of this method. In this study, we developed a multistage microfluidic device for continuous label-free separation and enrichment of rare cells from blood samples based on cell size and deformability. We successfully separated tumor cells (MCF-7 and HeLa cells) and leukemic (K562) cells spiked in diluted whole blood using a unique complementary combination of inertial microfluidics and steric hindrance in a microfluidic system. The processing parameters of the inertial focusing and steric hindrance regions were optimized to achieve high-throughput and high-efficiency separation, significant advantages compared with existing rare cell isolation technologies. The results from experiments with rare cells spiked in 1% hematocrit blood indicated >90% cell recovery at a throughput of 2.24 × 10(7) cells min(-1). The enrichment of rare cells was >2.02 × 10(5)-fold. Thus, this microfluidic system driven by purely hydrodynamic forces has practical potential to be applied either alone or as a sample preparation platform for fundamental studies and clinical applications.

Click synthesis of neutral, cationic, and zwitterionic poly(propargyl glycolide)-co-poly(ɛ-caprolactone)-based aliphatic polyesters as antifouling biomaterials.

With the development of polymer-based biomaterials, aliphatic polyesters have attracted considerable interest because of their non-toxicity, non-allergenic property, and good biocompatibility. However, the hydrophobic nature and the lack of side chain functionalities of aliphatic polyesters limit their biomedical applications. In this study, we prepared four new polyesters: poly(sulfobetaine methacrylate)-, poly(2-methacryloyloxyethyl phosphotidylcholine)-, poly(ethylene glycol)-, and quaternized poly[(2-dimethylamino)ethyl methacrylate]-grafted poly(propargyl glycolide)-co-poly(ɛ-caprolactone). Their synthesis was conducted through ring-opening polymerization of acetylene-functionalized lactones and subsequent graft of bioactive units using click chemistry. The chemical structures of the polyesters were characterized through nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. For studies on their hydrophilicity, stability, and anti-bioadhesive property, a series of polymeric surfaces of these polyesters was prepared by coating them onto glass substrates. The hydrophilicity and stability of these polyester surfaces were examined by contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy. Their anti-bioadhesive property was investigated through protein adsorption, as well as cellular and bacterial adhesion assays. The prepared polyesters showed good hydrophilicity and long-lasting stability, as well as significant anti-fouling property. The newly prepared polyesters could be developed as promising anti-fouling materials with extensive biomedical applications.

Antifouling properties of poly(dimethylsiloxane) surfaces modified with quaternized poly(dimethylaminoethyl methacrylate).

A quaternized poly(dimethylaminoethyl methacrylate)-grafted poly(dimethylsiloxane) (PDMS) surface (PDMS-QPDMAEMA) was successfully prepared in this study via solution-phase oxidation reaction and surface-initiated atom transfer radical polymerization (SI-ATRP) using dimethylaminoethyl methacrylate (DMAEMA) as initial monomer. PDMS substrates were first oxidized in H(2)SO(4)/H(2)O(2) solution to transform the SiCH(3) groups on their surfaces into SiOH groups. Subsequently, a surface initiator for ATRP was immobilized onto the PDMS surface, and DMAEMA was then grafted onto the PDMS surface via copper-mediated ATRP. Finally, the tertiary amino groups of PolyDMAEMA (PDMAEMA) were quaternized by ethyl bromide to provide a cationic polymer brush-modified PDMS surface. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy, were used to ascertain the successful grafting of the quaternized PDMAEMA brush onto the PDMS surface. Furthermore, the wettability and stability of the PDMS-QPDMAEMA surface were examined by contact angle measurements. Antifouling properties were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the PDMS-QPDMAEMA surface exhibited durable wettability and stability, as well as significant antifouling properties, compared with the native PDMS and PDMS-PDMAEMA surfaces. In addition, our results present possible uses for the PDMS-QPDMAEMA surface as adhesion barriers and antifouling or functional surfaces in PDMS microfluidics-based biomedical applications.