In Situ Assembly of Nanomaterials and Molecules for the Signal Enhancement of Electrochemical Biosensors

The physiochemical properties of nanomaterials have a close relationship with their status in solution. As a result of its better simplicity than that of pre-assembled aggregates, the in situ assembly of nanomaterials has been integrated into the design of electrochemical biosensors for the signal output and amplification. In this review, we highlight the significant progress in the in situ assembly of nanomaterials as the nanolabels for enhancing the performances of electrochemical biosensors. The works are discussed based on the difference in the interactions for the assembly of nanomaterials, including DNA hybridization, metal ion–ligand coordination, metal–thiol and boronate ester interactions, aptamer–target binding, electrostatic attraction, and streptavidin (SA)–biotin conjugate. We further expand the range of the assembly units from nanomaterials to small organic molecules and biomolecules, which endow the signal-amplified strategies with more potential applications.

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Excretion of Urea by the Foetal Guinea Pig

Clinical Science ◽

10.1042/cs0550329 ◽

1978 ◽

Vol 55 (4) ◽

pp. 329-333

Author(s):

Jane Horn

Keyword(s):

Guinea Pig ◽

Concentration Gradient ◽

Placental Transfer ◽

Maternal Plasma ◽

Plasma Urea ◽

Foetal Circulation ◽

Close Relationship ◽

Active Transfer ◽

The Difference

1. The placental transfer of urea was studied by perfusing the guinea-pig foetal placenta in situ with dextran solutions containing various amounts of urea, and radioactively labelled urea. 2. Transfer of urea was linearly related to the difference in concentration between the maternal and the foetal sides of the placenta, but transfer in both directions across the placenta was equal when the concentration of urea in the perfusing fluid was 2.5–3.5 mmol/l less than the maternal arterial value. This suggested that urea may be transferred against a concentration gradient. 3. Foetal plasma urea concentrations were found to be 0.5 mmol/l less than the maternal, suggesting that active transfer from the foetal circulation to the maternal can occur. However, because of the close relationship between foetal and maternal plasma urea (r = 0.96), it is concluded that the major control of foetal urea concentrations is by diffusion of urea between maternal and foetal extracellular fluids.

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An In Situ Reversible Heterodimeric Nanoswitch Controlled by Metal-Ion-Ligand Coordination Regulates the Mechanosensing and Differentiation of Stem Cells

Advanced Materials ◽

10.1002/adma.201803591 ◽

2018 ◽

Vol 30 (44) ◽

pp. 1803591 ◽

Cited By ~ 15

Author(s):

Heemin Kang ◽

Kunyu Zhang ◽

Hee Joon Jung ◽

Boguang Yang ◽

Xiaoyu Chen ◽

...

Keyword(s):

Stem Cells ◽

Metal Ion ◽

Ligand Coordination

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Rational Design of Polyamine-Based Cryogels for Metal Ion Sorption

Molecules ◽

10.3390/molecules25204801 ◽

2020 ◽

Vol 25 (20) ◽

pp. 4801

Author(s):

Irina Malakhova ◽

Yuliya Privar ◽

Yuliya Parotkina ◽

Aleksandr Mironenko ◽

Marina Eliseikina ◽

...

Keyword(s):

Metal Ion ◽

Rational Design ◽

Fixed Bed ◽

Diglycidyl Ether ◽

Ex Situ ◽

Advantages And Disadvantages ◽

Ion Sorption ◽

In Situ Formation ◽

The Difference

Here we report the method of fabrication of supermacroporous monolith sorbents (cryogels) via covalent cross-linking of polyallylamine (PAA) with diglycidyl ether of 1,4-butandiol. Using comparative analysis of the permeability and sorption performance of the obtained PAA cryogels and earlier developed polyethyleneimine (PEI) cryogels, we have demonstrated the advantages and disadvantages of these polymers as sorbents of heavy metal ions (Cu(II), Zn(II), Cd(II), and Ni(II)) in fixed-bed applications and as supermacroporous matrices for the fabrication of composite cryogels containing copper ferrocyanide (CuFCN) for cesium ion sorption. Applying the rate constant distribution (RCD) model to the kinetic curves of Cu(II) ion sorption on PAA and PEI cryogels, we have elucidated the difference in sorption/desorption rates and affinity constants of these materials and showed that physical sorption contributed to the Cu(II) uptake by PAA, but not to that by PEI cryogels. It was shown that PAA cryogels had significantly higher selectivity for Cu(II) sorption in the presence of Zn(II) and Cd(II) ions in comparison with that of PEI cryogels, while irreversible sorption of Co(II) ions by PEI can be used for the separation of Ni(II) and Co(II) ions. Using IR and Mössbauer spectroscopy, we have demonstrated that strong complexation of Cu(II) ions with PEI significantly affects the in situ formation of Cu(II) ferrocyanide nanosorbents leading to their inefficiency for Cs+ ions selective uptake, whereas PAA cryogel was applicable for the fabrication of efficient monolith composites via the in situ formation of CuFCN or loading of ex situ formed CuFCN colloids.

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An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010648x ◽

1988 ◽

Vol 46 ◽

pp. 884-885

Author(s):

D. Loretto ◽

J. M. Gibson ◽

S. M. Yalisove ◽

R. T. Tung

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Defect Density ◽

High Vacuum ◽

Ultra High Vacuum ◽

Ex Situ ◽

Metal Base ◽

In Situ Experiments ◽

Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

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Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651402 ◽

1975 ◽

Vol 34 (02) ◽

pp. 426-444 ◽

Cited By ~ 3

Author(s):

J Kahan ◽

I Nohén

Keyword(s):

Oral Anticoagulant Therapy ◽

Repeated Measurements ◽

Test Procedures ◽

Coagulation Activity ◽

Close Relationship ◽

Measured Activity ◽

Test Materials ◽

The Difference ◽

The Stability ◽

The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

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Metal ion-directed synthesis of two mixed-ligand coordination polymers: protective activity on acute kidney injury by reducing Nagl content in urine

Журнал структурной химии ◽

10.26902/jsc_id66767 ◽

2021 ◽

Vol 62 (1) ◽

Keyword(s):

Acute Kidney Injury ◽

Coordination Polymers ◽

Metal Ion ◽

Kidney Injury ◽

Mixed Ligand ◽

Protective Activity ◽

Directed Synthesis ◽

Ligand Coordination

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DNA-Electrochemical Biosensors: AFM Surface Characterisation and Application to Detection of In Situ Oxidative Damage to DNA

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207311004070628 ◽

2010 ◽

Vol 13 (7) ◽

pp. 628-640 ◽

Cited By ~ 29

Author(s):

S. Carlos B. Oliveira ◽

Ana Maria Oliveira-Brett

Keyword(s):

Oxidative Damage ◽

Electrochemical Biosensors ◽

Surface Characterisation ◽

Oxidative Damage To Dna

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Comparison of Mammography and Ultrasonography for Tumor Size of DCIS of Breast Cancer

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405614666180131163321 ◽

2019 ◽

Vol 15 (2) ◽

pp. 209-213

Author(s):

Yu Wang ◽

Jiantao Wang ◽

Haiping Wang ◽

Xinyu Yang ◽

Liming Chang ◽

...

Keyword(s):

Breast Cancer ◽

Correlation Coefficient ◽

Tumor Size ◽

Ductal Carcinoma ◽

Pearson Correlation ◽

Dense Breast ◽

Pathological Examination ◽

Negative Group ◽

The Difference

Objective: Accurate assessment of breast tumor size preoperatively is important for the initial decision-making in surgical approach. Therefore, we aimed to compare efficacy of mammography and ultrasonography in ductal carcinoma in situ (DCIS) of breast cancer. Methods: Preoperative mammography and ultrasonography were performed on 104 women with DCIS of breast cancer. We compared the accuracy of each of the imaging modalities with pathological size by Pearson correlation. For each modality, it was considered concordant if the difference between imaging assessment and pathological measurement is less than 0.5cm. Results: At pathological examination tumor size ranged from 0.4cm to 7.2cm in largest diameter. For mammographically determined size versus pathological size, correlation coefficient of r was 0.786 and for ultrasonography it was 0.651. Grouped by breast composition, in almost entirely fatty and scattered areas of fibroglandular dense breast, correlation coefficient of r was 0.790 for mammography and 0.678 for ultrasonography; in heterogeneously dense and extremely dense breast, correlation coefficient of r was 0.770 for mammography and 0.548 for ultrasonography. In microcalcification positive group, coeffient of r was 0.772 for mammography and 0.570 for ultrasonography. In microcalcification negative group, coeffient of r was 0.806 for mammography and 0.783 for ultrasonography. Conclusion: Mammography was more accurate than ultrasonography in measuring the largest cancer diameter in DCIS of breast cancer. The correlation coefficient improved in the group of almost entirely fatty/ scattered areas of fibroglandular dense breast or in microcalcification negative group.

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Influence of protein (human galectin-3) design on aspects of lectin activity

Histochemistry and Cell Biology ◽

10.1007/s00418-020-01859-9 ◽

2020 ◽

Vol 154 (2) ◽

pp. 135-153 ◽

Cited By ~ 1

Author(s):

Gabriel García Caballero ◽

Donella Beckwith ◽

Nadezhda V. Shilova ◽

Adele Gabba ◽

Tanja J. Kutzner ◽

...

Keyword(s):

Protein Design ◽

Full Range ◽

Biological Information ◽

The Novel ◽

Modular Assembly ◽

Binding Partners ◽

Galectin 3 ◽

Potential Applications ◽

Similar Affinity

Abstract The concept of biomedical significance of the functional pairing between tissue lectins and their glycoconjugate counterreceptors has reached the mainstream of research on the flow of biological information. A major challenge now is to identify the principles of structure–activity relationships that underlie specificity of recognition and the ensuing post-binding processes. Toward this end, we focus on a distinct feature on the side of the lectin, i.e. its architecture to present the carbohydrate recognition domain (CRD). Working with a multifunctional human lectin, i.e. galectin-3, as model, its CRD is used in protein engineering to build variants with different modular assembly. Hereby, it becomes possible to compare activity features of the natural design, i.e. CRD attached to an N-terminal tail, with those of homo- and heterodimers and the tail-free protein. Thermodynamics of binding disaccharides proved full activity of all proteins at very similar affinity. The following glycan array testing revealed maintained preferential contact formation with N-acetyllactosamine oligomers and histo-blood group ABH epitopes irrespective of variant design. The study of carbohydrate-inhibitable binding of the test panel disclosed up to qualitative cell-type-dependent differences in sections of fixed murine epididymis and especially jejunum. By probing topological aspects of binding, the susceptibility to inhibition by a tetravalent glycocluster was markedly different for the wild-type vs the homodimeric variant proteins. The results teach the salient lesson that protein design matters: the type of CRD presentation can have a profound bearing on whether basically suited oligosaccharides, which for example tested positively in an array, will become binding partners in situ. When lectin-glycoconjugate aggregates (lattices) are formed, their structural organization will depend on this parameter. Further testing (ga)lectin variants will thus be instrumental (i) to define the full range of impact of altering protein assembly and (ii) to explain why certain types of design have been favored during the course of evolution, besides opening biomedical perspectives for potential applications of the novel galectin forms.

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