Cistanche deserticola polysaccharide- functionalized dendritic fibrous nano-silica -based adjuvant for H9N2 oral vaccine enhance systemic and mucosal immunity in chickens.

Avian influenza virus subtype H9N2 has the ability to infect birds and humans, further causing significant losses to the poultry industry and even posing a great threat to human health. Oral vaccine received particular interest for preventing majority infection due to its ability to elicit both mucosal and systemic immune responses, but their development is limited by the bad gastrointestinal (GI) environment, compact epithelium and mucus barrier, and the lack of effective mucosal adjuvants. Herein, we developed the dendritic fibrous nano-silica (DFNS) grafted with Cistanche deserticola polysaccharide (CDP) nanoparticles (CDP-DFNS) as an adjuvant for H9N2 vaccine. Encouragingly, CDP-DFNS facilitated the proliferation of T and B cells, and further induced the activation of T lymphocytes in vitro. Moreover, CDP-DFNS/H9N2 significantly promoted the antigen-specific antibodies levels in serum and intestinal mucosal of chickens, indicating the good ability to elicit both systemic and mucosal immunity. Additional, CDP-DFNS facilitate the activation of CD4 + and CD8 + T cells both in spleen and intestinal mucosal, and the indexes of immune organs. This study suggested that CDP-DFNS may be a new avenue for development of oral vaccine against pathogens that are transmitted via mucosal route.

Probing actin-activated ATP turnover kinetics of human cardiac myosin II by single molecule fluorescence.

Mechanistic insights into myosin II energy transduction in striated muscle in health and disease would benefit from functional studies of a wide range of point-mutants. This approach is, however, hampered by the slow turnaround of myosin II expression that usually relies on adenoviruses for gene transfer. A recently developed virus-free method is more time effective but would yield too small amounts of myosin for standard biochemical analyses. However, if the fluorescent adenosine triphosphate (ATP) and single molecule (sm) total internal reflection fluorescence microscopy previously used to analyze basal ATP turnover by myosin alone, can be expanded to actin-activated ATP turnover, it would appreciably reduce the required amount of myosin. To that end, we here describe zero-length cross-linking of human cardiac myosin II motor fragments (sub-fragment 1 long [S1L]) to surface-immobilized actin filaments in a configuration with maintained actin-activated ATP turnover. After optimizing the analysis of sm fluorescence events, we show that the amount of myosin produced from C2C12 cells in one 60 mm cell culture plate is sufficient to obtain both the basal myosin ATP turnover rate and the maximum actin-activated rate constant (kcat). Our analysis of many single binding events of fluorescent ATP to many S1L motor fragments revealed processes reflecting basal and actin-activated ATPase, but also a third exponential process consistent with non-specific ATP-binding outside the active site.

A new non-enzymatic biosensor for the determination of bisphenol-A.

In this study, a new non-enzymatic carbon paste biosensor was developed for the determination of Bisphenol-A (BPA) based on Multiwalled Carbon Nanotube (MWCNT) modified Myoglobin (Mb). The measurement principle of the biosensor was developed based on the inhibition effect of BPA on the heme group of myoglobin in the presence of hydrogen peroxide. With the designed biosensor, measurements were taken in the potential range of (-0.15 V & +0.65 V) using the differential pulse voltammetry (DPV) method in the medium containing K4[Fe(CN)6]. The linear range for BPA was determined to be 100-1000 µM. Response time was calculated as 16 s. The limit of detection was set at 89 µM. As a result, it has been proven that MWCNT modified myoglobin based biosensor is an alternative method that can be used for BPA determination, giving very sensitive and fast results.

Repair of tendons treated with peracetic acid-ethanol and gamma irradiation by EDC combined with NHS: a morphological, biochemical and biomechanical study in vitro.

The purpose of this study was to investigate whether 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) combined with n-hydroxysuccinimide (NHS) can repair tendon damage caused by peracetic acid-ethanol and gamma irradiation sterilization. The semitendinosus tendons of 15 New Zealand white rabbits were selected as experimental materials, and the tendons were sterilized in a solution containing 1% (v/w) peracetic acid and 24% (v/w) ethanol. After 15 kGy gamma irradiation sterilization, the tendons were randomly divided into three groups (n = 10). The tendons were repaired with EDCs of 0, 2.5 and 5 mM combined with 5 mM NHS for 6 h, the tendons were temporarily stored at - 80 ± °C. The arrangement and spatial structure of collagen fibers were observed by light microscopy and scanning electron microscopy, the collagen type and collagen crimp period were observed under a polarizing microscope, and the collagen fibril diameter and its distribution were measured by transmission electron microscopy, from which the collagen fibril index and mass average diameter were calculated. The resistance of collagen to enzymolysis was detected by the free hydroxyproline test, and tensile fracture and cyclic loading tests of each group of tendons were carried out, from which the elastic modulus, maximum stress, maximum strain, strain energy density and cyclic creep strain were calculated. The obtained results showed that the gap between loose collagen fibers in the 0 mM control group was wider, the parallel arrangement of tendons in the 2.5 and 5 mM groups was more uniform and regular and the fiber space decreased, the crimp period in the 5 mM group was lower than that in the 0 mM group (P < 0.05), and the concentration of hydroxyproline in the 5 mM group (711.64 ± 77.95 µg/g) was better than that in the control group (1150.57 ± 158.75 µg/g). The elastic modulus of the 5 mM group (424.73 ± 150.96 MPa) was better than that of the 0 mM group (179.09 ± 37.14 MPa). Our results show that EDC combined with NHS can repair damaged tendons after peracetic acid-ethanol and gamma radiation treatment, and 5 mM EDC has better morphological performance, anti-enzymolysis ability and biomechanical properties than 2.5 mM EDC.

Batteryless wireless magnetostrictive Fe30Co70/Ni clad plate for human coronavirus 229E detection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been garnered increasing for its rapid worldwide spread. Each country had implemented city-wide lockdowns and immigration regulations to prevent the spread of the infection, resulting in severe economic consequences. Materials and technologies that monitor environmental conditions and wirelessly communicate such information to people are thus gaining considerable attention as a countermeasure. This study investigated the dynamic characteristics of batteryless magnetostrictive alloys for energy harvesting to detect human coronavirus 229E (HCoV-229E). Light and thin magnetostrictive Fe-Co/Ni clad plate with rectification, direct current (DC) voltage storage capacitor, and wireless information transmission circuits were developed for this purpose. The power consumption was reduced by improving the energy storage circuit, and the magnetostrictive clad plate under bending vibration stored a DC voltage of 1.9 V and wirelessly transmitted a signal to a personal computer once every 5 min and 10 s under bias magnetic fields of 0 and 10 mT, respectively. Then, on the clad plate surface, a novel CD13 biorecognition layer was immobilized using a self-assembled monolayer of -COOH groups, thus forming an amide bond with -NH2 groups for the detection of HCoV-229E. A bending vibration test demonstrated the resonance frequency changes because of HCoV-229E binding. The fluorescence signal demonstrated that HCoV-229E could be successfully detected. Thus, because HCoV-229E changed the dynamic characteristics of this plate, the CD13-modified magnetostrictive clad plate could detect HCoV-229E from the interval of wireless communication time. Therefore, a monitoring system that transmits/detects the presence of human coronavirus without batteries will be realized soon.

Synthesis of Glycyrrhizic Acid Conjugates with Amino-Acid Methyl Esters and their Ability to Stimulate Antibody Genesis in Mice.

Conjugates of glycyrrhizic acid (GA) with methyl esters of L-amino acids (valine, methionine, and glutamic acid) containing the amino-acid residues in the carbohydrate moiety of the glycoside were synthesized using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The resulting GA conjugates at a dose of 2 mg/kg stimulated a primary immune response (production of antibody-forming cells, AFCs) in outbred mice by 1.6 - 3 times as compared with the control. The conjugate of GA with Glu(OMe)2 stimulated antibody genesis in outbred mice 1.7 times more efficiently than N-acetylmuramyl dipeptide and showed a stimulating effect on AFC production in the spleen of CBA mice.

[Effects of different crosslinking treatments on the properties of decellularized small intestinal submucosa porous scaffolds].

OBJECTIVE: To compare the effects of three different crosslinkers on the biocompatibility, physical and chemical properties of decellularized small intestinal submucosa (SIS) porous scaffolds. METHODS: The SIS porous scaffolds were prepared by freeze-drying method and randomly divided into three groups, then crosslinked by glutaraldehyde (GA), 1-ethyl-3-(3-dimethylaminopropyl) carbodi-imide (EDC) and procyanidine (PA) respectively. To evaluate the physicochemical property of each sample in different groups, the following experiments were conducted. Macroscopic morphologies were observed and recorded. Microscopic morphologies of the scaffolds were observed using field emission scanning electron microscope (FESEM) and representative images were selected. Computer software (ImageJ) was used to calculate the pore size and porosity. The degree of crosslinking was determined by ninhydrin experiment. Collagenase degradation experiment was performed to assess the resistance of SIS scaffolds to enzyme degradation. To evaluate the mechanical properties, universal mechanical testing machine was used to determine the stress-strain curve and compression strength was calculated. Human bone marrow mesenchymal cells (hBMSCs) were cultured on the scaffolds after which cytotoxicity and cell proliferation were assessed. RESULTS: All the scaffolds remained intact after different crosslinking treatments. The FESEM images showed uniformed interconnected micro structures of scaffolds in different groups. The pore size of EDC group[(161.90±13.44) µm] was significantly higher than GA group [(149.50±14.65) µm] and PA group[(140.10±12.06) µm] (P < 0.05). The porosity of PA group (79.62%±1.14%) was significantly lower than EDC group (85.11%±1.71%) and GA group (84.83%±1.89%) (P < 0.05). PA group showed the highest degree of crosslinking whereas the lowest swelling ratio. There was a significant difference in the swelling ratio of the three groups (P < 0.05). Regarding to the collagenase degradation experiment, the scaffolds in PA group showed a significantly lower weight loss rate than the other groups after 7 days degradation. The weight loss rates of GA group were significantly higher than those of the other groups on day 15, whereas the PA group had the lowest rate after 10 days and 15 days degradation. PA group showed better mechanical properties than the other two groups. More living cells could be seen in PA and EDC groups after live/dead cell staining. Additionally, the proliferation rate of hBMCSs was faster in PA and EDC groups than in GA group. CONCLUSION: The scaffolds gained satisfying degree of crosslinking after three different crosslinking treatments. The samples after PA and EDC treatment had better physicochemical properties and biocompatibility compared with GA treatment. Crosslinking can be used as a promising and applicable method in the modification of SIS scaffolds.

Effect of type of fatty acid attached to chitosan on walnut oil-in-water Pickering emulsion properties.

The effect of fatty acid type bonded to chitosan on the emulsifying properties of chitosan-based particles was investigated. Capric acid, myristic acid, and stearic acid were attached to chitosan chains. Longer fatty acids in the structure of chitosan lead to the better and more uniform formation of chitosan nanogels. The contact angle of chitosan, chitosan-capric acid, chitosan-myristic acid and chitosan-stearic acid were found to be 52.5°, 60.0°, 65.1° and 72.5°, respectively. Different chitosan nanogels were used to stabilize walnut oil emulsions, and the emulsion stabilized with chitosan-stearic acid nanogels had the lowest creaming index (15.2%). Stabilized emulsions with chitosans attached to longer chain acids were more adapted to the mechanism of Pickering emulsions, in addition to having higher viscosity as well as more gel-like behavior. In general, this study showed that emulsifying properties of chitosan could be improved by increasing the number of fatty acid carbons bonded to chitosan.

Cross-Linking Agents for Electrospinning-Based Bone Tissue Engineering.

Electrospun nanofibers are promising bone tissue scaffolds that support bone healing due to the body's structural similarity to the extracellular matrix (ECM). However, the insufficient mechanical properties often limit their potential in bone tissue regeneration. Cross-linking agents that chemically interconnect as-spun electrospun nanofibers are a simple but effective strategy for improving electrospun nanofibers' mechanical, biological, and degradation properties. To improve the mechanical characteristic of the nanofibrous bone scaffolds, two of the most common types of cross-linking agents are used to chemically crosslink electrospun nanofibers: synthetic and natural. Glutaraldehyde (GTA) is a typical synthetic agent for electrospun nanofibers, while genipin (GP) is a natural cross-linking agent isolated from gardenia fruit extracts. GP has gradually gained attention since GP has superior biocompatibility to synthetic ones. In recent studies, much more progress has been made in utilizing crosslinking strategies, including citric acid (CA), a natural cross-linking agent. This review summarizes both cross-linking agents commonly used to improve electrospun-based scaffolds in bone tissue engineering, explains recent progress, and attempts to expand the potential of this straightforward method for electrospinning-based bone tissue engineering.

Chemo-photothermal immunotherapy for eradication of orthotopic tumors and inhibition of metastasis by intratumoral injection of polydopamine versatile hydrogels.

Cancer remains one of the leading causes of death globally and metastasis always leads to treatment failure. Here, we develop a versatile hydrogel loading photothermal agents, chemotherapeutics, and immune-adjuvants to eradicate orthotopic tumors and inhibit metastasis by combinational therapy. Hydrogel networks were synthesized via the thiol-Michael addition of polydopamine (PDA) with thiolated hyaluronic acid. PDA acted as a cross-linking agent and endowed the hydrogel with excellent photothermal property. Meanwhile, a chemotherapeutic agent, doxorubicin (DOX), was loaded in the hydrogel via π‒π stacking with PDA and an immune-adjuvant, CpG-ODN, was loaded via electrostatic interaction. The release of DOX from the hydrogel was initially slow but accelerated due to near infrared light irradiation. The hydrogels showed remarkably synergistic effect against 4T1 cancer cells and stimulated plenty of cytokines secreting from RAW264.7 cells. Moreover, the hydrogels eradicated orthotopic murine breast cancer xenografts and strongly inhibited metastasis after intratumoral injection and light irradiation. The high anticancer efficiency of this chemo-photothermal immunotherapy resulted from the strong synergistic effect of the versatile hydrogels, including the evoked host immune response. The combinational strategy of chemo-photothermal immunotherapy is promising for highly effective treatment of breast cancer.

Delivery of acetogenin-enriched Annona muricata Linn leaf extract by folic acid-conjugated and triphenylphosphonium-conjugated poly(glycerol adipate) nanoparticles to enhance toxicity against ovarian cancer cells.

The study demonstrated the fabrication of new poly(glycerol adipate) (PGA) nanoparticles decorated with folic acid (FOL-PGA) and triphenylphosphonium (TPP-PGA) and the potential on the delivery of acetogenin-enriched Annona muricata Linn leaf extract to ovarian cancer cells. FOL-PGA and TPP-PGA were successfully synthesized and used to fabricate FOL-decorated nanoparticles (FOL-NPs) and FOL-/TPP- decorated nanoparticles (FOL/TPP-NPs) by blending two polymers at a mass ratio of 1:1. All nanoparticles had small size of around 100 nm, narrow size distribution and high negative surface charge about -30 mV. The stable FOL/TPP-NPs showed highest drug loading of 14.9 ± 1.9% at 1:5 ratio of extract to polymer and reached to 35.8 ± 2.1% at higher ratio. Both nanoparticles released the extract in a biphasic sustained release manner over 5 days. The toxicity of the extract to SKOV3 cells was potentiated by FOL-NPs and FOL/TPP-NPs by 2.0 - 2.6 fold through induction of cell apoptosis. FOL/TPP-NPs showed lower IC50 and higher cellular uptake as compared to FOL-NPs. FOL-NPs exhibited folate receptor-mediated endocytosis. FOL/TPP-NPs provided more advantages than FOL-NPs in terms of stability in physiological fluid, uptake efficiency and targeting ability to mitochondria and showed a promising potential PGA platform for targeted delivery of herbal cytotoxic extracts.

Gold nanorods-mediated efficient synergistic immunotherapy for detection and inhibition of postoperative tumor recurrence.

Tumor recurrence after surgery is the main cause of treatment failure. However, the initial stage of recurrence is not easy to detect, and it is difficult to cure in the late stage. In order to improve the life quality of postoperative patients, an efficient synergistic immunotherapy was developed to achieve early diagnosis and treatment of post-surgical tumor recurrence, simultaneously. In this paper, two kinds of theranostic agents based on gold nanorods (AuNRs) platform were prepared. AuNRs and quantum dots (QDs) in one agent was used for the detection of carcinoembryonic antigen (CEA), using fluorescence resonance energy transfer (FRET) technology to indicate the occurrence of in situ recurrence, while AuNRs in the other agent was used for photothermal therapy (PTT), together with anti-PDL1 mediated immunotherapy to alleviate the process of tumor metastasis. A series of assays indicated that this synergistic immunotherapy could induce tumor cell death and the increased generation of CD3+/CD4+ T-lymphocytes and CD3+/CD8+ T-lymphocytes. Besides, more immune factors (IL-2, IL-6, and IFN-γ) produced by synergistic immunotherapy were secreted than mono-immunotherapy. This cooperative immunotherapy strategy could be utilized for diagnosis and treatment of postoperative tumor recurrence at the same time, providing a new perspective for basic and clinical research.

An insect acetylcholinesterase biosensor utilizing WO3/g-C3N4 nanocomposite modified pencil graphite electrode for phosmet detection in stored grains.

This study was undertaken to assess the potential of Tribolium castaneum (Red flour beetle) acetylcholinesterase (Tc-AChE) based electrochemical biosensor integrating WO3/g-C3N4 nanocomposite modified Pencil graphite electrode to detect an organophosphate insecticide, Phosmet. The WO3/g-C3N4 nanocomposite provides a non-toxic, biocompatible surface for binding the enzyme on the electrode surface, attributed to its large surface area, high conductivity, and low ohmic resistance. The proposed biosensor shows a very good analytical performance with LOD 3.6 nM for Phosmet and effectively determined Phosmet in wheat with a 99% recovery rate. Furthermore, molecular docking deciphers the binding interactions of Phosmet with Tc-AChE using a modified AutoDock LGA algorithm and an AMBER03 force field in YASARA. The kinetic parameters strongly suggest the high potency of inhibitor with the enzyme. This study presents an adaptable, rapid, and straightforward approach that opens ways towards real progress in developing commercial biosensors for pesticide detection.

Biomimetic glycosaminoglycan-based scaffolds improve skeletal muscle regeneration in a Murine volumetric muscle loss model.

Volumetric muscle loss (VML) injuries characterized by critical loss of skeletal muscle tissues result in severe functional impairment. Current treatments involving use of muscle grafts are limited by tissue availability and donor site morbidity. In this study, we designed and synthesized an implantable glycosaminoglycan-based hydrogel system consisting of thiolated hyaluronic acid (HA) and thiolated chondroitin sulfate (CS) cross-linked with poly(ethylene glycol) diacrylate to promote skeletal muscle regeneration of VML injuries in mice. The HA-CS hydrogels were optimized with suitable biophysical properties by fine-tuning degree of thiol group substitution to support C2C12 myoblast proliferation, myogenic differentiation and expression of myogenic markers MyoD, MyoG and MYH8. Furthermore, in vivo studies using a murine quadriceps VML model demonstrated that the HA-CS hydrogels supported integration of implants with the surrounding host tissue and facilitated migration of Pax7+ satellite cells, de novo myofiber formation, angiogenesis, and innervation with minimized scar tissue formation during 4-week implantation. The hydrogel-treated and autograft-treated mice showed similar functional improvements in treadmill performance as early as 1-week post-implantation compared to the untreated groups. Taken together, our results demonstrate the promise of HA-CS hydrogels as regenerative engineering matrices to accelerate healing of skeletal muscle injuries.

Evaluation of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide Cross-Linked Collagen Membranes for Guided Bone Regeneration in Beagle Dogs.

The purpose of this study was to evaluate the bone regeneration efficacy of an 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-cross-linked collagen membrane for guided bone regeneration (GBR). A non-cross-linked collagen membrane (Control group), and an EDC-cross-linked collagen membrane (Test group) were used in this study. In vitro, mechanical, and degradation testing and cell studies were performed. In the animal study, 36 artificial bone defects were formed in the mandibles of six beagles. Implants were inserted at the time of bone grafting, and membranes were assigned randomly. Eight weeks later, animals were sacrificed, micro-computed tomography was performed, and hematoxylin-eosin stained specimens were prepared. Physical properties (tensile strength and enzymatic degradation rate) were better in the Test group than in the Control group. No inflammation or membrane collapse was observed in either group, and bone volumes (%) in defects around implants were similar in the two groups (p > 0.05). The results of new bone areas (%) analysis also showed similar values in the two groups (p > 0.05). Therefore, it can be concluded that cross-linking the collagen membranes with EDC is the method of enhancing the physical properties (tensile strength and enzymatic degradation) of the collagen membranes without risk of toxicity.

Effects of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide on adhesion of posts in teeth obturated with different sealers

Abstract The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.

Resumo O objetivo deste estudo foi avaliar o efeito da 1-etil-3- (3-dimetilaminopropil) carbodiimida (EDC) na resistência de união de pinos de fibra de vidro em canais radiculares obturados com diferentes cimentos endodônticos. Setenta e oito pré-molares inferiores foram obturados com três cimentos endodônticos (n=26): Endofill (END), AH Plus (AHP) e Endosequence BC Sealer (EBS). Após o preparo do espaço para pino, dois subgrupos formaram-se conforme a cimentação dos pinos (n=13): com EDC e sem EDC (controle - CON). Os espécimes foram submetidos ao teste pull-out, classificação do modo de falha e avaliação da superfície do canal radicular por microscopia eletrônica de varredura após o deslocamento. Quanto à força de resistência de união, uma diferença estatisticamente significativa ocorreu entre os subgrupos EDC e CON apenas no END (p=0,001). Não foi detectada diferença entre os subgrupos CON (p=0,339). Contudo, no subgrupo EDC, o AHP apresentou maiores valores (END versus AHP: p=0,001; AHP versus EBS: p=0,016). Acerca da classificação dos modos de falha, o escore 1 (≥50% de cimento) foi o mais comumente observado, exceto para END + EDC. Restos de cimentos endodônticos e cimentos resinosos foram encontrados no terço cervical, mas sem diferença estatística (p=0,269), enquanto no terço médio, houve diferença (p=0,004). Em conclusão, o EDC diminui a resistência de união quando associado ao cimento END, sem alterar o modo de falha entre o cimento resinoso e o pino de fibra de vidro. O melhor desempenho foi observado quanto o EDC foi usado com o cimento AHP.

Towards Efficient Nonenzymatic DNA Ligation: Comparing Key Parameters for Maximizing Ligation Rates and Yields with Carbodiimide Activation*.

Chemical ligation is an important tool for the generation of synthetic DNA structures, which are used for a wide range of applications. Surprisingly, reported chemical ligation yields can range from 30 to 95 % for the same chemical activating agent and comparable DNA structures. We report a systematic study of DNA ligation by using a well-defined bimolecular test system and a water-soluble carbodiimide (EDC) as a phosphate-activating agent. Our results emphasize the interplay between template-substrate complex stability and the rates of the chemical steps of ligation, with 3' phosphate substrates providing yields near 100 % after 24 hours for particularly favorable reaction conditions. Ligation rates are also shown to be sensitive to the identity of the base pairs flanking a nick site, with as much as threefold variation. Finally, the observation that DNA substrates are modified by EDC at rates that can be comparable with ligation rates emphasizes the importance of considering side reactions when designing protocols to maximize ligation yields.

Heparin-conjugated collagen as a potent growth factor-localizing and stabilizing scaffold for regenerative medicine.

INTRODUCTION: Growth factors are crucial bioactive molecules in vitro and in vivo. Among them, basic fibroblast growth factor (bFGF) has been used widely for various applications such as cell culture and regenerative medicine. However, bFGF has extremely poor stability in aqueous solution; thus, it is difficult to maintain its high local concentration. Heparin-conjugated materials have been studied recently as promising scaffold-immobilizing growth factors for biological and medical applications. The previous studies have focused on the local concentration maintenance and sustained release of the growth factors from the scaffold. METHODS: In this paper, we focused on the biological stability of bFGF immobilized on the heparin-conjugated collagen (hep-col) scaffold. The stability of the immobilized bFGF was quantitatively evaluated at physiological temperature (37 °C) using cell culture and ELISA. RESULTS: The immobilized bFGF had twice higher stability than the bFGF solution. Furthermore, the hep-col scaffold was able to immobilize not only bFGF but also other growth factors (i.e., vascular endothelial growth factor and hepatocyte growth factor) at high efficiency. CONCLUSIONS: The hep-col scaffold can localize several kinds of growth factors as well as stabilize bFGF under physiological temperature and is a promising potent scaffold for regenerative medicine.

Targeted imaging of breast cancer cells using two different kinds of aptamers -functionalized nanoparticles.

Breast cancer which is the most commonly diagnosed cancer among women; have been known as a serious threat for health and life around the world. So development of an approach for early-stage diagnosis of breast cancer is vital. In this study, we designed a double aptamer-nanoparticle conjugates-based (DANP) complex for specific detection and visualization of MCF-7 cells using Mucin 1 (MUC 1) aptamer-conjugated gold nanoparticles (MUC1 apt - GNPs) and adenosine triphosphate (ATP) aptamer-conjugated CdTe quantum dots (ATP apt-QDs). The ATP apt-QDs was attached onto MUC1 apt - GNPs surface through Van der Waals forces and electrostatic interactions between ATP aptamer and GNPs leading to the formation of DANP complex. Atomic force microscopy asserted DANP complex formation. The imaging process was based on the recognition of MUC1 protein on the surface of MCF-7 cells by MUC1 aptamer and specific internalization of DANP complex into target cells (MCF-7). Existence of abundant amounts of ATP in lysosome led to release of ATP apt-QDs from the MUC1 apt-GNPs surface resulting in strong fluorescence emission. The flow cytometry analysis and fluorescence microscopy confirmed significant internalization of DANP complex into MCF-7 cells (target) in comparison with CHO cells (non-target). Based on the obtained results, the DANP complex possesses high potency for efficient detection and monitoring of breast cancer cells (MCF-7).