scholarly journals Conjugation of Carbon Dots with β-Galactosidase Enzyme: Surface Chemistry and Use in Biosensing

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3275 ◽  
Author(s):  
Shiv K. Sharma ◽  
Miodrag Micic ◽  
Shanghao Li ◽  
Benjamin Hoar ◽  
Suraj Paudyal ◽  
...  
Keyword(s):  
Detection Limit ◽  
Surface Functionalization ◽  
Self Assembly ◽  
Carbon Dots ◽  
Response Rate ◽  
High Response Rate ◽  
High Demand ◽  
Sensing Platform ◽  
Therapy Development ◽  
Useful Lifetime

Nanoparticles have been conjugated to biological systems for numerous applications such as self-assembly, sensing, imaging, and therapy. Development of more reliable and robust biosensors that exhibit high response rate, increased detection limit, and enhanced useful lifetime is in high demand. We have developed a sensing platform by the conjugation of β-galactosidase, a crucial enzyme, with lab-synthesized gel-like carbon dots (CDs) which have high luminescence, photostability, and easy surface functionalization. We found that the conjugated enzyme exhibited higher stability towards temperature and pH changes in comparison to the native enzyme. This enriched property of the enzyme was distinctly used to develop a stable, reliable, robust biosensor. The detection limit of the biosensor was found to be 2.9 × 10−4 M, whereas its sensitivity was 0.81 µA·mmol−1·cm−2. Further, we used the Langmuir monolayer technique to understand the surface properties of the conjugated enzyme. It was found that the conjugate was highly stable at the air/subphase interface which additionally reinforces the suitability of the use of the conjugated enzyme for the biosensing applications.

scholarly journals Synthesis of aminated polystyrene and its self-assembly with nanoparticles at oil/water interface

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 317-327
Author(s):  
Chenliang Shi ◽  
Ling Lin ◽  
Yukun Yang ◽  
Wenjia Luo ◽  
Maoqing Deng ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Self Assembly ◽  
Carbon Dots ◽  
Chain Transfer ◽  
Functionalized Polymers ◽  
Amino Groups ◽  
One Dimensional ◽  
Reversible Addition ◽  
Oil Water ◽  
Chain Transfer Polymerization

AbstractThe influence of density of amino groups, nanoparticles dimension and pH on the interaction between end-functionalized polymers and nanoparticles was extensively investigated in this study. PS–NH2 and H2N–PS–NH2 were prepared using reversible addition–fragmentation chain transfer polymerization and atom transfer radical polymerization. Zero-dimensional carbon dots with sulfonate groups, one-dimensional cellulose nanocrystals with sulfate groups and two-dimensional graphene with sulfonate groups in the aqueous phase were added into the toluene phase containing the aminated PS. The results indicate that aminated PS exhibited the strongest interfacial activity after compounding with sulfonated nanoparticles at a pH of 3. PS ended with two amino groups performed better in reducing the water/toluene interfacial tension than PS ended with only one amino group. The dimension of sulfonated nanoparticles also contributed significantly to the reduction in the water/toluene interfacial tension. The minimal interfacial tension was 4.49 mN/m after compounding PS–NH2 with sulfonated zero-dimensional carbon dots.

scholarly journals Plasmonic Sensing Studies of a Gas-Phase Cystic Fibrosis Marker in Moisture Laden Air

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3776
Author(s):  
Libin Sun ◽  
Douglas Conrad ◽  
Drew A. Hall ◽  
Kurt D. Benkstein ◽  
Steve Semancik ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Detection Limit ◽  
Gas Phase ◽  
Localized Surface Plasmon ◽  
Exhaled Breath ◽  
Nanohole Array ◽  
Dry Air ◽  
Plasmonic Sensing ◽  
Sensing Platform ◽  
The Status

A plasmonic sensing platform was developed as a noninvasive method to monitor gas-phase biomarkers related to cystic fibrosis (CF). The nanohole array (NHA) sensing platform is based on localized surface plasmon resonance (LSPR) and offers a rapid data acquisition capability. Among the numerous gas-phase biomarkers that can be used to assess the lung health of CF patients, acetaldehyde was selected for this investigation. Previous research with diverse types of sensing platforms, with materials ranging from metal oxides to 2-D materials, detected gas-phase acetaldehyde with the lowest detection limit at the µmol/mol (parts-per-million (ppm)) level. In contrast, this work presents a plasmonic sensing platform that can approach the nmol/mol (parts-per-billion (ppb)) level, which covers the required concentration range needed to monitor the status of lung infection and find pulmonary exacerbations. During the experimental measurements made by a spectrometer and by a smartphone, the sensing examination was initially performed in a dry air background and then with high relative humidity (RH) as an interferent, which is relevant to exhaled breath. At a room temperature of 23.1 °C, the lowest detection limit for the investigated plasmonic sensing platform under dry air and 72% RH conditions are 250 nmol/mol (ppb) and 1000 nmol/mol (ppb), respectively.

Two Orders of Magnitude Improvement in the Detection Limit of Droplet-Based Micro-Magnetofluidics with Planar Hall Effect Sensors

2021 ◽  
Vol 6 (1) ◽  
pp. 47
Author(s):  
Julian Schütt ◽  
Rico Illing ◽  
Oleksii Volkov ◽  
Tobias Kosub ◽  
Pablo Nicolás Granell ◽  
...  
Keyword(s):  
Detection Limit ◽  
Hall Effect ◽  
State Of The Art ◽  
Limit Of Detection ◽  
Research Field ◽  
High Throughput Analysis ◽  
Planar Hall Effect ◽  
Biologically Relevant ◽  
Sensing Platform ◽  
Order Of Magnitude

The detection, manipulation, and tracking of magnetic nanoparticles is of major importance in the fields of biology, biotechnology, and biomedical applications as labels as well as in drug delivery, (bio-)detection, and tissue engineering. In this regard, the trend goes towards improvements of existing state-of-the-art methodologies in the spirit of timesaving, high-throughput analysis at ultra-low volumes. Here, microfluidics offers vast advantages to address these requirements, as it deals with the control and manipulation of liquids in confined microchannels. This conjunction of microfluidics and magnetism, namely micro-magnetofluidics, is a dynamic research field, which requires novel sensor solutions to boost the detection limit of tiny quantities of magnetized objects. We present a sensing strategy relying on planar Hall effect (PHE) sensors in droplet-based micro-magnetofluidics for the detection of a multiphase liquid flow, i.e., superparamagnetic aqueous droplets in an oil carrier phase. The high resolution of the sensor allows the detection of nanoliter-sized superparamagnetic droplets with a concentration of 0.58 mg cm−3, even when they are only biased in a geomagnetic field. The limit of detection can be boosted another order of magnitude, reaching 0.04 mg cm−³ (1.4 million particles in a single 100 nL droplet) when a magnetic field of 5 mT is applied to bias the droplets. With this performance, our sensing platform outperforms the state-of-the-art solutions in droplet-based micro-magnetofluidics by a factor of 100. This allows us to detect ferrofluid droplets in clinically and biologically relevant concentrations, and even in lower concentrations, without the need of externally applied magnetic fields.

A highly efficient chiral sensing platform for tryptophan isomers based on a coordination self-assembly

Talanta ◽  
2019 ◽  
Vol 195 ◽  
pp. 306-312 ◽  
Author(s):  
Peng Lei ◽  
Ying Zhou ◽  
Guomei Zhang ◽  
Yan Zhang ◽  
Caihong Zhang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Highly Efficient ◽  
Sensing Platform ◽  
Chiral Sensing

scholarly journals Paper, E-mail, or Both? Effects of Contact Mode on Participation in a Web Survey of Establishments

2018 ◽  
Vol 37 (6) ◽  
pp. 750-765 ◽  
Author(s):  
Joseph W. Sakshaug ◽  
Basha Vicari ◽  
Mick P. Couper
Keyword(s):  
Response Rate ◽  
Population Based ◽  
High Response Rate ◽  
Nonresponse Bias ◽  
Web Survey ◽  
Participation Rates ◽  
Web Surveys ◽  
Contact Mode ◽  
Mail Address ◽  
E Mail

Identifying strategies that maximize participation rates in population-based web surveys is of critical interest to survey researchers. While much of this interest has focused on surveys of persons and households, there is a growing interest in surveys of establishments. However, there is a lack of experimental evidence on strategies for optimizing participation rates in web surveys of establishments. To address this research gap, we conducted a contact mode experiment in which establishments selected to participate in a web survey were randomized to receive the survey invitation with login details and subsequent reminder using a fully crossed sequence of paper and e-mail contacts. We find that a paper invitation followed by a paper reminder achieves the highest response rate and smallest aggregate nonresponse bias across all-possible paper/e-mail contact sequences, but a close runner-up was the e-mail invitation and paper reminder sequence which achieved a similarly high response rate and low aggregate nonresponse bias at about half the per-respondent cost. Following up undeliverable e-mail invitations with supplementary paper contacts yielded further reductions in nonresponse bias and costs. Finally, for establishments without an available e-mail address, we show that enclosing an e-mail address request form with a prenotification letter is not effective from a response rate, nonresponse bias, and cost perspective.

scholarly journals Characteristics and treatment outcomes of patients with primary ocular adnexal lymphoma in Northern Thailand

2020 ◽  
Vol 17 (1) ◽  
pp. 86-97
Author(s):  
Kasem Seresirikachorn ◽  
Sakarin Ausayakhun ◽  
Damrong Wiwatwongwana ◽  
Ponsak Mahanupab ◽  
Teerada Daroontum ◽  
...  
Keyword(s):  
Treatment Outcomes ◽  
Response Rate ◽  
Stage Iv ◽  
High Response Rate ◽  
University Hospital ◽  
Treatment Modalities ◽  
Low Grade ◽  
Northern Thailand ◽  
Ocular Adnexal Lymphoma ◽  
Operative Notes

Purpose: To assess the characteristics and treatment outcomes of patients with primary ocular adnexal lymphoma (OAL) in Northern Thailand. Design: Retrospective cohort study. Methods: Data was collected from electronic medical records and operative notes from Chiang Mai University Hospital between January 2009 and December 2014. All available tissue biopsies of 54 patients were reviewed by agreement of two pathologists. The clinical characteristics and treatment outcomes were collected and analyzed. Results: A total number of 54 patients were identified of which 57.4% were female. The median age was 61.0 years (range, 4-86). The most common subtype of lymphoma was extranodal marginal zone lymphoma (ENMZL) of mucosa-associated lymphoid tissue (MALT) (n = 46, 85.2%). Seventy-five percent of the patients presented with a mass at the ocular adnexa, while 14.8% of the patients presented with proptosis. The sites of origin were as follows: lacrimal (46.3%), orbit (31.5%), conjunctiva (13%) and eyelid (7.4%). Two-thirds of the patients had Ann-Arbor Stage I, while 22% of patients had Stage IV. The majority of the patients (68.1%) had a low-risk international prognosis index (IPI). Treatment modalities involved field radiation (IFRT, 50%), chemotherapy (31.6%), combined chemoradiotherapy (7.9%) and surgical resection (10.5%). The overall response rate was 100% with a complete response rate of 77.8%. In patients with low-grade lymphoma, including MALT lymphoma, the 3-year progression-free survival (PFS) and overall survival were 69.9% and 92.5%, respectively. Conclusion: ENMZL of MALT was the major subtype of primary OAL. Radiotherapy was an effective treatment for the lower stages of disease providing a high response rate and encouraging survival outcomes.

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