Red blood cell membrane-functionalized Nanofibrous tubes for small-diameter vascular grafts.

The off-the-shelf small-diameter vascular grafts (SDVGs) have inferior clinical efficacy. Red blood cell membrane (Rm) has easy availability and multiple bioactive components (such as phospholipids, proteins, and glycoproteins), which can improve the clinic's availability and patency of SDVGs. Here we developed a facile approach to preparing an Rm-functionalized poly-ε-caprolactone/poly-d-lysine (Rm@PCL/PDL) tube by co-incubation and single-step rolling. The integrity, stability, and bioactivity of Rm on Rm@PCL/PDL were evaluated. The revascularization of Rm@PCL/PDL tubes was studied by implantation in the carotid artery of rabbits. Rm@PCL/PDL can be quickly prepared and showed excellent bioactivity with good hemocompatibility and great anti-inflammatory. Rm@PCL/PDL tubes as the substitute for the carotid artery of rabbits had good patency and quick remodeling within 21 days. Rm, as a "self" biomaterial with high biosafety, provides a new and facile approach to developing personalized or universal SDVGs for the clinic, which is of great significance in cardiovascular regenerative medicine and organ chip.

Anticoagulant Hydrogel Tubes with Poly(ɛ-Caprolactone) Sheaths for Small-Diameter Vascular Grafts.

Small-diameter vascular grafts (inner diameter < 6 mm) are useful in treating cardiovascular diseases. The off-the-shelf small-diameter vascular grafts for clinical applications remain a great limitation owing to their thrombogenicity or intimal hyperplasia. Herein, bilayer anticoagulant hydrogel tubes with poly(ε-caprolactone) (PCL) sheaths are prepared by freeze-thawing and electrospinning, which contain nanofibrillated cellulose (NFC)/poly(vinyl alcohol) (PVA)-heparin/poly-L-lysine nanoparticles tube as an inner layer and PCL sheath as an outer layer. The structure, anticoagulant property, and biocompatibility of the inner layer are studied. The effects of thickness of the outer layer on perfusion performance and mechanical property of hydrogel tubes with PCL sheaths (PCL-NFC/PVA-NPs tubes) are investigated. The effect of compliance of PCL-NFC/PVA-NPs tubes on their blood flow is studied by numerical simulation. The tissue compatibility and the patency of PCL-NFC/PVA-NPs tubes are evaluated by implantation in subcutaneous tissue of rats and carotid artery of rabbits. PCL-NFC/PVA-NPs tubes have prominent anticoagulation, sufficient burst pressure and good compliance similar to native arteries. PCL-NFC/PVA-NPs tubes facilitate infiltration of host cells and achieve active proliferation of recruited cells, which will be a promising candidate for small-diameter vascular grafts.

Two dimensional nanosheets as immunoregulator improve HIV vaccine efficacy.

Two-dimensional (2D) nanosheets as carriers have shown promising potential for surface-displaying or loading various drugs. Nevertheless, developing sheet-like materials themselves into an immunoregulator has never been realized so far. In this study, we take advantage of the immunoregulatory effects of rare earth elements themselves and develop water-soluble erbium-dysprosium 2D nanosheets (2D NSs). Such 2D NSs can target lymph nodes and activate macrophages to improve vaccine efficacy in mice significantly. Transcriptome analysis further reveals that six critical molecules (Msr1, Ccr2, Serpinb9, Klrk1, Klrd1, Klrc1) closely correlate with 2D NS-mediated immunoregulation in vivo. For the first time, the present work realizes a proof-of-concept for designing immunoregulatory 2D NSs and shows a promising potential of 2D NSs for improving the immunoprophylaxis/immunotherapy of vaccines.

Surface-modified mesoporous nanofibers for microfluidic immunosensor with an ultra-sensitivity and high signal-to-noise ratio.

How to balance the sensitivity and signal-to-noise ratio of immunosensor remains many challenges during various diseases diagnosis. Here we develop a new microfluidic immunosensor based on surface-modified mesoporous nanofibers, and simultaneously realize an ultra-sensitivity and high signal-to-noise ratio for the detection of multiple biomarkers. In the current study, we fabricated titanium dioxide (TiO2)-based mesoporous electrospinning nanofibers, and modified nanofiber surface with both octadecylphosphonic acid (OPA) and poly(ethylene oxide)-poly(propylene oxide) triblock copolymer (PEO-PPO-PEO). Such nanofibers as solid substrate are covered on microfluidic channels. The porosity of our nanofibers dramatically increased the adsorption capability of antibodies, realizing an ultra sensitivity of biomarker detection. PEO-PPO-PEO modification can significantly block non-specific absorptions, obtaining a satisfied signal-to-noise ratio. For the detection of HIV p24 and interleukin 5 (IL-5), our immunosensor increased 6.41 and 6.93 fold in sensitivity and improved 504.66% and 512.80% in signal-to-noise ratio, in compared with gold standard immunoassay (ELISA) used in the clinic. Our immunosensor also broaden the linear range for the detection of HIV p24 (0.86-800 pg/ml) and IL-5 (0.70-800 pg/ml), in compared with ELISA which is 5.54-500 pg/ml for HIV p24 and 4.84-500 pg/ml for IL-5. Our work provided a guideline for the construction of advanced point-of-care immunosensor with an ultra-sensitivity and high signal-to-noise ratio for disease diagnosis.

Increasing the Assembly Efficacy of Peptidic ß-Sheets for a Highly-Sensitive HIV Detection.

Our recent publication illustrates the critical role of phenylalanine-mediated aromatic-aromatic interactions in determining the assembly of peptidic ß-sheets. However, the effect of phenylalanine number on regulating the assembly efficacy of peptidic ß-sheets remains poorly understood. We herein evaluate the assembly efficacy of ß-sheets of a series of oligopeptides which contain 0, 1, 2, or 3 phenylalanine in their molecular backbones. In our assembly system, two phenylalanine (2F) is the minimum number for driving the assembly of ß-sheets of oligopeptides. Oligopeptides with three phenylalanine (3F) show significantly increased assembly efficacy of ß-sheets compared to that with 2F. These results suggest a positive correlation between the phenylalanine number and assembly efficacy of ß-sheets. By improving the assembly efficacy of ß-sheets, we further develop a highly sensitive HIV analytical system in which the specific binding of ß-sheets with Congo Red induces enhanced fluorescence. For HIV p24 detection, the 3F-based analytical system (0.61 pg/mL) shows a significantly lower limit of detection (LOD) than the 2F-based analytical system (2.44 pg/mL), both of which are more sensitive than commercial ELISA (5 pg/mL) used in the clinic. This work not only illustrates the effect of phenylalanine number on regulating the assembly efficacy of ß-sheets but also provides a guideline for the construction of a highly sensitive analytical system of disease diagnosis.

Hierarchically structured microchip for point-of-care immunoassays with dynamic detection ranges.

Point-of-care (POC) medical assays provide critical information to guide clinical therapy for a broad range of medical scenarios, such as resource-poor settings and specialty departments in hospitals. Even though many types of POC assays can be done in automated devices, these POC assays typically cannot well accommodate the multiplexed detection of biomarkers where a large dynamic range is needed. Here, we report a POC assay, which is both automated and suitable for detecting multiple biomarkers with dynamic detection ranges. We call it a dynamic multiplexed immunoassay (DMI). We control the concentrations of capture antibodies and the intensity of the readout signal to dynamically modulate the detection range of immunoassays (pg mL-1 to µg mL-1), leading to the multiplexed detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin 6 (IL-6) simultaneously in undiluted human serum samples. The POC assay allows the rapid and accurate detection of infection in patients.

Capillary-based chemiluminescence immunoassay for C-reactive protein with portable imaging device.

A capillary-based chemiluminescence immunoassay system using a charge-coupled device (CCD) camera as detector was established in this paper. The fused quartz capillary was easily activated in one step for immobilizing capture antibody, and the chemiluminescence immunoassay was carried out in the capillary in double-antibody sandwich format. Chemiluminescence signals were recorded by the portable imaging device which was installed with the CCD camera and the results were analyzed through gray intensity. The total cost time, which included not only the time for test but also the time for the preparation of experimental materials, was only 2 h. The immunoassay was performed without any complicated or expensive instruments. The consumption of the sample was only 0.8 µL in one test, which was significantly less than other methods. In this work, C-reactive protein (CRP), as a target, was quantitatively detected from 0.3 to 160.0 µg mL-1 with high specificity and low sample volume. The reproducibility and accuracy were tested in clinic human serum samples and shown good results. Thus, this rapid, easy preparation and using, portable immunoassay system indicated its usefulness as a novel technology platform. Graphical abstract ᅟ.

[Effects of extracellular calcium concentration on platelets aggregation, coagulation indices and thromboelastography].

OBJECTIVE: To detect the effect of extracellular Ca2+ concentrations on test results of coagulation-related parameters. METHODS: Blood samples of outpatient medical volunteers were collected and then different doses of calcium chloride added. The rate of platelet aggregation (n = 42), prothrombin time (PT), thrombin time (TT) and activated partial thromboplastin time (APTT) (n = 21) and parameters of thromboelastography (n = 30) were detected according to the standard protocols by plasma turbidimetry, coagulation and recalcification respectively. RESULTS: When the plasma Ca2+ concentration was in the range of 0.1 - 33.7 mmol/L, the rate of platelet aggregation gradually increased with a increasing concentration of Ca2+. And the rates induced by adenosine diphosphate (ADP) and arachidonic acid (AA) were (51.8 +/- 9.6)% - (94.7 +/- 4.8)% and (64.4 +/- 12.2)% - (93.2 +/- 5.5)% respectively. When the Ca2+ concentration was 39.0 mmol/L, the rate decreased markedly [ADP (9.1 +/- 5.3)%, AA (11.1 +/- 4.5)%, both P < 0.01]. When the Ca2+ concentration was in the range of 0.1 - 33.7 mmol/L, the values of PT gradually increased with a increasing concentration of Ca2+. The values of TT changed in "V"-type and became minimum when the calcium concentration was 4.4 mmol/L. The values of APTT decreased with higher calcium concentrations and could not be determined when the concentration increased above 0.5 mmol/L. When the Ca2+ concentration was in the range of 0.4 - 27.3 mmol/L, the values of reaction time and coagulation time of thromboelastography changed in "V"-type and became nearly minimal at the Ca2+ concentration of about 2.1 mmol/L. The values of alpha angle and maximum amplitude changed in "V"-type and became maximal at the Ca2+ concentration of 2.1 mmol/L. CONCLUSIONS: The effect of Ca2+ concentration on the testing results of coagulation-related parameters is significant. A high calcium ( > or = 39 mmol/L) can inhibit the platelet aggregation, coagulation factor activity and blood coagulation. The Ca2+ concentration of 2.1 mmol/L seems to be the optimal concentration for thromboelastography by recalcification method.