Reactive protein-repellent surfaces for the straightforward attachment of small molecules up to whole cells

2012 ◽  
Vol 3 (10) ◽  
pp. 3000 ◽  
Author(s):  
Stijn F. M. van Dongen ◽  
Julie Janvore ◽  
Sander S. van Berkel ◽  
Emmanuelle Marie ◽  
Matthieu Piel ◽  
...  
Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1455
Author(s):  
Emilio Iturriaga-Goyon ◽  
Beatriz Buentello-Volante ◽  
Fátima Sofía Magaña-Guerrero ◽  
Yonathan Garfias

Aptamers are single-stranded DNA or RNA oligonucleotides that are currently used in clinical trials due to their selectivity and specificity to bind small molecules such as proteins, peptides, viral particles, vitamins, metal ions and even whole cells. Aptamers are highly specific to their targets, they are smaller than antibodies and fragment antibodies, they can be easily conjugated to multiple surfaces and ions and controllable post-production modifications can be performed. Aptamers have been therapeutically used for age-related macular degeneration, cancer, thrombosis and inflammatory diseases. The aim of this review is to highlight the therapeutic, diagnostic and prognostic possibilities associated with aptamers, focusing on eye pathological angiogenesis.


1984 ◽  
Vol 4 (2) ◽  
pp. 247-253 ◽  
Author(s):  
M A Hoosein ◽  
A S Lewin

Pulse-chase labeling in whole cells and cell-free protein synthesis were used to establish that the mitochondrial enzyme citrate synthase is made as a larger precursor in Saccharomyces cerevisiae. A 54,000 Mr precursor form appeared to be a primary translation product since it could be labeled with N-[35S]formylmethionine in vitro. The induction of citrate synthase was monitored in S. cerevisiae cells grown on fermentable (glucose) and nonfermentable (ethanol and glycerol) carbon sources. The amount of citrate synthase activity and immune-reactive protein increased more than 15-fold as S. cerevisiae cells entered the stationary growth phase on glucose-containing medium. This increase was paralleled by an increase in translatable RNA for the enzyme. When cells were grown on a nonfermentable carbon source, no increase in either citrate synthase or its mRNA was detected. The results suggest that the release of citrate synthase from catabolite repression may occur at the level of transcription.


2021 ◽  
Author(s):  
marcus pollard ◽  
Rhushabh Maugi ◽  
Angelika Holzinger ◽  
Micheal Scanlon ◽  
Mark Platt

Resistive pulse sensors have been used to characterise everything from whole cells to small molecules. Their integration into microfluidic devices have simplified sample handling whilst increasing throughput. Typically, these devices measure a limited size range or a specific analyte, making them prone to blockages in complex sample matrixes. To prolong their life and facilitate their use, samples are often filtered or prepared to match the sample with the sensor diameter. Here, we advance our tuneable flow resistive pulse sensor which utilises additively manufactured parts. The sensor allows parts to be easily changed, washed and cleaned, its simplicity and versatility allows components from existing nanopore fabrication techniques such as silicon nitride, polyurethane and glass pipettes to be integrated into a single device. This creates a multi-nanopore sensor that can simultaneously measure particles from 0.1 to 30 m in diameter. The orientation and controlled fluid flow in the device allows the sensors to be placed in series, whereby smaller particles can be measured in the presence of larger ones without the risk of being blocked. We demonstrate the device with a range of nanopore materials commonly found within the literature, the easiest to set up was the pulled glass pipette and glass nanopore membrane. However, the glass nanopore membrane was by far the most robust and reusable component tested. We illustrate the concept of a multi-pore flow resistive pulse sensor, by combining an additively manufactured tuneable sensor, termed sensor 1, with a fixed nanopore sensor, termed sensor 2. Sensor 1 measures particles 2 to 30 m in diameter, whilst sensor 2 can be used to characterise particles as small as 100 nm, depending upon its dimensions.


2019 ◽  
Vol 24 (4) ◽  
pp. 359-372
Author(s):  
Dino Di Carlo

The next generation of therapies is moving beyond the use of small molecules and proteins to using whole cells. Compared with the interactions of small-molecule drugs with biomolecules, which can largely be understood through chemistry, cell therapies act in a chemical and physical world and can actively adapt to that world, amplifying complexity but also the potential for truly breakthrough impact. Although there has been success in introducing targeting proteins into cells to achieve a therapeutic effect, for example, chimeric antigen receptor (CAR) T cells, our ability to engineer cells is generally limited to introducing proteins, but not modulating large-scale traits or structures of cellular “machines,” which play critical roles in disease. Example traits include the ability to secrete compounds, deform through tissue, adhere to surrounding cells, apply force to phagocytose targets, or move through extracellular matrix. There is an opportunity to increase the efficacy of cell therapies through the use of quantitative automation tools, to analyze, sort, and select rare cells with beneficial traits. Combined with methods of genetic or epigenetic mutagenesis to create diversity, such approaches can enable the directed cellular evolution of new therapeutically optimal populations of cells and uncover genetic underpinnings of these optimal traits.


2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
Cindy Meyer ◽  
Ulrich Hahn ◽  
Andrea Rentmeister

Aptamers are short nucleic acids that bind to defined targets with high affinity and specificity. The first aptamers have been selected about two decades ago by anin vitroprocess named SELEX (systematic evolution of ligands by exponential enrichment). Since then, numerous aptamers with specificities for a variety of targets from small molecules to proteins or even whole cells have been selected. Their applications range from biosensing and diagnostics to therapy and target-oriented drug delivery. More recently, selections using complex targets such as live cells have become feasible. This paper summarizes progress in cell-SELEX techniques and highlights recent developments, particularly in the field of medically relevant aptamers with a focus on therapeutic and drug-delivery applications.


1984 ◽  
Vol 4 (2) ◽  
pp. 247-253
Author(s):  
M A Hoosein ◽  
A S Lewin

Pulse-chase labeling in whole cells and cell-free protein synthesis were used to establish that the mitochondrial enzyme citrate synthase is made as a larger precursor in Saccharomyces cerevisiae. A 54,000 Mr precursor form appeared to be a primary translation product since it could be labeled with N-[35S]formylmethionine in vitro. The induction of citrate synthase was monitored in S. cerevisiae cells grown on fermentable (glucose) and nonfermentable (ethanol and glycerol) carbon sources. The amount of citrate synthase activity and immune-reactive protein increased more than 15-fold as S. cerevisiae cells entered the stationary growth phase on glucose-containing medium. This increase was paralleled by an increase in translatable RNA for the enzyme. When cells were grown on a nonfermentable carbon source, no increase in either citrate synthase or its mRNA was detected. The results suggest that the release of citrate synthase from catabolite repression may occur at the level of transcription.


2021 ◽  
Author(s):  
Ann-Kathrin Kissmann ◽  
Jakob Andersson ◽  
Heinz Fabian Raber ◽  
Markus Krämer ◽  
Hu Xing ◽  
...  

Oligonucleotide DNA aptamers represent an emergently important class of binding entities towards as different analytes as small molecules or even whole cells. Without the canonical isolation of individual aptamers following the SELEX process already the focused polyclonal libraries prepared by this in vitro evolution and selection can directly be used to label their dedicated analytes and to serve as binding molecules on surfaces. Here we report the first instance of a sensor able to discriminate between loaded and unloaded retinol binding protein 4 (RBP4), an important biomarker for the prediction of diabetes and kidney disease. The sensor relies purely on two aptamer libraries tuned such, that they discriminate between the protein isoforms, requiring no further sample labelling to detect RBP4 in both state. The evolution, binding properties of the libraries and the functionalization of graphene FET sensor chips are presented as well as the functionality of the resulting biosensor.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 724
Author(s):  
Robert Ziółkowski ◽  
Marta Jarczewska ◽  
Łukasz Górski ◽  
Elżbieta Malinowska

This paper focuses on the current state of art as well as on future trends in electrochemical aptasensors application in medical diagnostics. The origin of aptamers is presented along with the description of the process known as SELEX. This is followed by the description of the broad spectrum of aptamer-based sensors for the electrochemical detection of various diagnostically relevant analytes, including metal cations, abused drugs, neurotransmitters, cancer, cardiac and coagulation biomarkers, circulating tumor cells, and viruses. We described also possible future perspectives of aptasensors development. This concerns (i) the approaches to lowering the detection limit and improvement of the electrochemical aptasensors selectivity by application of the hybrid aptamer–antibody receptor layers and/or nanomaterials; and (ii) electrochemical aptasensors integration with more advanced microfluidic devices as user-friendly medical instruments for medical diagnostic of the future.


Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.


Author(s):  
W. E. Rigsby ◽  
D. M. Hinton ◽  
V. J. Hurst ◽  
P. C. McCaskey

Crystalline intracellular inclusions are rarely seen in mammalian tissues and are often difficult to positively identify. Lymph node and liver tissue samples were obtained from two cows which had been rejected at the slaughter house due to the abnormal appearance of these organs in the animals. The samples were fixed in formaldehyde and some of the fixed material was embedded in paraffin. Examination of the paraffin sections with polarized light microscopy revealed the presence of numerous crystals in both hepatic and lymph tissue sections. Tissue sections were then deparaffinized in xylene, mounted, carbon coated, and examined in a Phillips 505T SEM equipped with a Tracor Northern X-ray Energy Dispersive Spectroscopy (EDS) system. Crystals were obscured by cellular components and membranes so that EDS spectra were only obtainable from whole cells. Tissue samples which had been fixed but not paraffin-embedded were dehydrated, embedded in Spurrs plastic, and sectioned.


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