Researchers from IISER Mohali have developed a novel approach for investigating the aggregation and patterning of nanobioconjugate in a microfluidic channel and glass slide. The study, published in ACS Nano, explores the use of diffusiophoresis in an enzyme gradient to drive the patterning and aggregation of nanoparticles.
Summary:
- IISER Mohali researchers investigate the aggregation and patterning of nanobioconjugate in a microfluidic channel and glass slide.
- The study uses diffusiophoresis in an enzyme gradient to drive the patterning and aggregation of nanoparticles.
- The researchers observed aggregation of the nanoparticles in the presence of alkaline phosphatase (ALP) enzyme and anionic nucleotides, leading to a coffee ring pattern in a droplet containing a specific GNP-ATP conjugate.
- The findings have potential applications in low-cost on-the-spot disease diagnostics.
The study demonstrates four phenomena: (i) how the aggregation of nanoparticles takes place in the presence of nucleotide and alkaline phosphatase in homogeneous conditions, (ii) the collective migratory and aggregation behavior of nanoparticles with a response to the enzyme in catalytic and noncatalytic conditions under microfluidic conditions, (iii) how this aggregation can get patterned in macroscale regimes over a glass slide, and (iv) the coffee ring pattern from an evaporating droplet, also applicable in a clinically relevant sample, blood serum.
The study showed that specific enzyme-substrate binding while the substrate also has a high binding affinity to the nanoparticle surface can lead to aggregation. In this case, ATP had a much stronger binding affinity to the nanoparticle surface as well as with enzyme and therefore led to faster aggregation compared to products (adenosine + Pi).
The research is a significant step in the development of new diagnostic tools, especially in low-resource settings. The ability to pattern and aggregate nanobioconjugates in a controlled manner could lead to the development of novel assays for detecting disease biomarkers in bodily fluids.
Outcomes:
- The study showed that a cationic surfactant-bound gold nanoparticle (GNP) surface sequesters anionic nucleotides, leading to aggregation in the presence of alkaline phosphatase (ALP) enzyme.
- The researchers also observed the formation of a coffee ring pattern from an evaporating droplet solution of aqueous buffer and blood serum containing a specific GNP-ATP conjugate, which can have applicability in low-cost on-the-spot disease diagnostics.
- The findings of this work can contribute to ongoing research on enzyme-substrate interactivity driven colloidal chemotaxis-cum-phoresis and clustering inspired by purinosome or metabolon formation and their application in forensics to diagnostics assays
Self-Regulatory Micro-and Macroscale Patterning of ATP-Mediated Nanobioconjugate
Shandilya; Maiti
Full-text link: https://doi.org/10.1021/acsnano.3c00431
What this paper is about
- The specific features and advan-tages of this strategy are that synergistic interactivity leads to coexisting assembly and patterning of both nanoparticles and enzymes in a micro-and millimeter scale region of a microfluidic channel and glass slide by a diffusiophoretic process, and modulation of the coffee ring pattern by the presence of a specific ATP-loaded nanoparticle with enzymes and translation of this effect in a drying blood serum droplet, which can have applicability in low-cost on-the-spot disease diagnostics.
- Until now, research in this area has mostly been confined to free enzyme or liposome-bound enzymes and free-substrate systems.
- Finally, a coffee ring formation pattern from an evaporating droplet solution of aqueous buffer and blood serum due the presence of a specific GNP-ATP conjugate has been explored.
What you can learn
- IISER Mohali Researchers checked this using a GNP-tagged fluorescent bead, which also showed higher aggregation only in the presence of ATP and ALP, observed clearly from the fluorescence microscope images.
- Interestingly, the zeta potential decreased to 10 2 mV in the simultaneous presence of ALP and ATP at our experimental condition after 1 h. We also checked the zeta potential of GNP in the presence of AMP and ADP in the presence of ALP in two separate experiments.
- It suggests that probably the presence of nucleotides on the surface of GNP also made the enzyme reside on the nanoparticle surface and the extent of aggregation with ALP is higher in the presence of strongly bound nucleotides.
- In the presence of only serum, we observed clear coffee ring formation as the beads deposited on the edge of the droplet.
- In presence of GNP only in blood serum, we did not observe clear coffee ring like deposition of the fluorescent beads like the previous case.
- In experiment, it has been found that specific enzymesubstrate binding while the substrate also has a high binding affinity to the nanoparticle surface can lead to aggregation.
Core Q&A related to this research
What is the main focus of this paper?
The paper investigates the aggregation and patterning of a nanobioconjugate in a microfluidic channel and glass slide by diffusiophoresis in an enzyme gradient. The authors explore how the aggregation of nanoparticles takes place in the presence of nucleotide and alkaline phosphatase in homogeneous conditions, the collective migratory and aggregation behavior of nanoparticles with a response to the enzyme in catalytic and noncatalytic conditions under microfluidic conditions, how this aggregation can get patterned in macroscale regimes over a glass slide, and the coffee ring pattern from an evaporating droplet, which can have applicability in low-cost on-the-spot disease diagnostics.
What is the significance of the coffee ring pattern mentioned in the paper?
The coffee ring pattern is generated from an evaporating droplet solution of aqueous buffer and blood serum containing a specific GNP-ATP conjugate. The authors explore how this effect can be applied in a clinically relevant sample, blood serum, and potentially used in low-cost on-the-spot disease diagnostics.
What is the relationship between ATP, ALP, and GNP?
In the experiments, it has been found that specific enzyme-substrate binding while the substrate also has a high binding affinity to the nanoparticle surface can lead to aggregation. In this case, ATP has a much stronger binding affinity to the nanoparticle surface as well as with enzyme and therefore led to faster aggregation compared to products (adenosine + Pi). The authors also suggest that the presence of nucleotides on the surface of GNP may make the enzyme reside on the nanoparticle surface and the extent of aggregation with ALP is higher in the presence of strongly bound nucleotides.
What is the contribution of this work to ongoing research in this area?
The findings of this work can contribute to the expansion of ongoing research on enzyme-substrate interactivity driven colloidal chemotaxis-cum-phoresis and clustering inspired by purinosome or metabolon formation and their application in forensics to diagnostics assays. The paper demonstrates a strategy where synergistic interactivity leads to coexisting assembly and patterning of both nanoparticles and enzymes in a micro-and millimeter scale region of a microfluidic channel and glass slide by a diffusiophoretic process. The authors suggest that until now, research in this area has mostly been confined to free enzyme or liposome-bound enzymes and free-substrate systems.
Basics Q&A related to this research
What is a microfluidic channel?
A microfluidic channel is a small-scale channel or tube, typically with dimensions on the order of micrometers, used to manipulate and study fluid flow and chemical reactions on a small scale.
What is a glass slide?
A glass slide is a flat, thin piece of glass used for viewing objects under a microscope.
What is diffusiophoresis?
Diffusiophoresis is a phenomenon in which particles in a fluid move in response to a concentration gradient of a solute, such as an enzyme, in the fluid.
What is an enzyme gradient?
An enzyme gradient is a variation in the concentration of an enzyme in a fluid, typically due to a localized source of the enzyme.
What is a cationic surfactant?
A cationic surfactant is a molecule with a positively charged functional group that is used to stabilize and modify the surface properties of nanoparticles, such as gold nanoparticles.
What is a gold nanoparticle (GNP)?
A gold nanoparticle (GNP) is a small particle made of gold atoms that is typically on the nanoscale range of size.
What are anionic nucleotides?
Anionic nucleotides are molecules containing a phosphate group with a negative charge, which are involved in cellular processes such as energy transfer and signal transduction.
What are adenosine mono/di/triphosphate (AMP/ADP/ATP)?
Adenosine mono/di/triphosphate (AMP/ADP/ATP) are types of anionic nucleotides that play important roles in cellular energy transfer and metabolism.
What is alkaline phosphatase (ALP)?
Alkaline phosphatase (ALP) is an enzyme that catalyzes the hydrolysis of phosphate esters at alkaline pH values.
What is a coffee ring pattern?
A coffee ring pattern is a circular pattern that forms when a liquid droplet containing particles or solutes evaporates on a surface.
What is an aqueous buffer?
An aqueous buffer is a solution of a weak acid and its conjugate base that is used to maintain a stable pH in a reaction or experiment.
What is blood serum?
Blood serum is the clear, liquid portion of blood that remains after blood cells and clotting factors have been removed.
What is nanoparticle aggregation?
Nanoparticle aggregation is the process by which nanoparticles come together to form clusters or aggregates.
What is enzyme-substrate interactivity?
Enzyme-substrate interactivity refers to the interaction between an enzyme and its substrate, which results in the catalysis of a chemical reaction.
What is colloidal chemotaxis?
Colloidal chemotaxis is the movement of colloidal particles, such as nanoparticles, in response to a chemical gradient.
What are purinosome and metabolon?
Purinosome and metabolon are structures that are formed when enzymes and their substrates aggregate together in specific patterns in order to carry out metabolic processes efficiently.
What is disease diagnostics?
Disease diagnostics refers to the use of various techniques and tools to diagnose the presence or absence of a disease in a patient.
What is an ATP-loaded nanoparticle?
An ATP-loaded nanoparticle is a gold nanoparticle that has been modified to bind to and carry adenosine triphosphate (ATP), a molecule that is important in cellular energy metabolism.
What is zeta potential?
Zeta potential is a measure of the electrical potential that exists at the surface of a nanoparticle or other colloidal particle, which is related to the stability and behavior of the particle in solution.
