Stimuli-Responsive Hydrogels Overview
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Questions and Answers

What was the cumulative release percentage of spinosyn after 18 days at a pH of 6.8?

  • 89%
  • 80% (correct)
  • 64%
  • 75%

    • Which property allows the PDA@PNIPAm nanosystem to exhibit responsiveness to external stimuli?

  • pH and temperature
  • pH and pressure
  • Temperature and humidity
  • Temperature and infrared light (correct)

    • Which of the following statements is true regarding the degradation of polymer-based carriers in the environment?

  • They require special conditions for degradation.
  • They can degrade into harmful chemicals.
  • They remain unchanged over time.
  • They biodegrade into water and carbon dioxide. (correct)

    • At what temperature did the sustained release of IMI reach 64% within 5 hours?

    <p>40 °C</p> Signup and view all the answers

    What percentage of oxamidil was released from the nanocomposite at a pH of 9 within 120 hours?

    <p>65%</p> Signup and view all the answers

    How much higher was the release of IMI with NIR irradiation compared to the non-irradiated group?

    <p>10%</p> Signup and view all the answers

    What was the cumulative release percentage of oxamidil at pH 5 within 120 hours?

    <p>38%</p> Signup and view all the answers

    What aspect of long-term use of polymer-based carriers requires further investigation?

    <p>Impact on soil microbial populations and plants</p> Signup and view all the answers

    What is a primary benefit of using controlled-release fertilizers?

    <p>Increased efficiency of nutrient use</p> Signup and view all the answers

    Which of the following mechanisms is involved in the balance between abscisic acid and gibberellin in plants?

    <p>Management of seed dormancy</p> Signup and view all the answers

    What is the effect of gibberellin on the plant Jatropha curcas?

    <p>Stimulates shoot branching</p> Signup and view all the answers

    What challenges are associated with the clinical translation of stimuli-responsive polymers?

    <p>Difficulties in synthesis scalability</p> Signup and view all the answers

    Which of the following describes the use of enhanced-efficiency fertilizers?

    <p>As mitigation options for greenhouse gas emissions</p> Signup and view all the answers

    Which type of hydrogel has been employed for the extraction and determination of malachite green?

    <p>pH-sensitive hydrogel</p> Signup and view all the answers

    What is a significant outcome of using plant growth regulators such as paclobutrazol?

    <p>They selectively inhibit plant growth.</p> Signup and view all the answers

    What is the primary use of cloud point extraction with hydrogels in the context of environmental science?

    <p>Preconcentration of contaminants</p> Signup and view all the answers

    What is the effect of increasing pH on the release of pesticide in an alginate@silica carrier?

    <p>Release increases significantly with higher pH levels</p> Signup and view all the answers

    What is the primary advantage of using modified silica nanoparticles in agrochemical applications?

    <p>Excellent stability and biocompatibility</p> Signup and view all the answers

    Which fabrication method is used for preparing porous polyethyleneimine-grafted lignin microspheres?

    <p>Inverse suspension copolymerization</p> Signup and view all the answers

    At which pH level does the cumulative release of Aba insecticide significantly increase?

    <p>pH 10</p> Signup and view all the answers

    What is the adsorption capacity of porous polyethyleneimine-grafted lignin microspheres for 2,4-D?

    <p>909.09 mg/g</p> Signup and view all the answers

    What is a significant characteristic of the pH-responsive materials discussed?

    <p>They respond variably to changes in pH, enabling controlled release.</p> Signup and view all the answers

    What role does the methanol-water mixture play in the release process of the Aba insecticide?

    <p>It enhances release under alkaline conditions.</p> Signup and view all the answers

    Which of the following is NOT a characteristic of silica nanoparticles in agrochemical applications?

    <p>Poor interaction with soil components</p> Signup and view all the answers

    What primary method is utilized for the synthesis of cloud point extraction using pH-sensitive hydrogels?

    <p>Chemical crosslinking</p> Signup and view all the answers

    Which synthesis technique can enhance the efficiency of controlled-release fertilizers?

    <p>Fluidized bed coating</p> Signup and view all the answers

    In the context of plant growth regulators, what is a significant consideration during the synthesis of Paclobutrazol?

    <p>Temperature during polymerization</p> Signup and view all the answers

    Which of the following is a challenging aspect of synthesizing stimuli-responsive polymers?

    <p>Controlling degradation rates</p> Signup and view all the answers

    What is a crucial factor in the synthesis process of enhanced-efficiency fertilizers?

    <p>Chemical stability of additives</p> Signup and view all the answers

    What type of polymerization method is commonly applied in synthesizing pH-sensitive hydrogels?

    <p>Chain-growth polymerization</p> Signup and view all the answers

    What synthesis condition is critical for enhancing the stability of hydrogels used in environmental science?

    <p>Controlled pH levels</p> Signup and view all the answers

    Which aspect is most challenging when synthesizing materials for enhanced-efficiency fertilizers?

    <p>Achieving slow-releasing properties</p> Signup and view all the answers

    What synthesis method was used for preparing porous polyethyleneimine-grafted lignin microspheres?

    <p>Reverse suspension copolymerization</p> Signup and view all the answers

    Which agent was used as a pore-forming component in the preparation of PLM?

    <p>PEG</p> Signup and view all the answers

    What reaction was utilized to graft alginate onto the silica surface?

    <p>Ugi reaction</p> Signup and view all the answers

    What type of nanoparticles has gained attention for its effective response to pH in sustained drug release?

    <p>Silica nanoparticles</p> Signup and view all the answers

    Which process is used to prepare MSNs-PDA-Cu nanoparticles?

    <p>Chemical chelation</p> Signup and view all the answers

    What is the primary purpose of modifying silica nanoparticles with alginate?

    <p>To increase pH sensitivity</p> Signup and view all the answers

    What significant change occurs when the pH is increased from 3 to 8 in the context of pesticide release?

    <p>Increase in pesticide release</p> Signup and view all the answers

    The cumulative release of Aba insecticide is significantly influenced by what environmental condition?

    <p>pH level of the environment</p> Signup and view all the answers

    What is the primary function of Fe3+ in the construction of the DACMC-CYS-Fe hydrogel?

    <p>Serving as a secondary crosslinking agent</p> Signup and view all the answers

    Which material in the synthesis of the dual-responsive nanosystem is responsible for loading oxamidil?

    <p>Graphene oxide (GO)</p> Signup and view all the answers

    What characteristic of the PDA@PNIPAm nanosystem supports its dual responsiveness to environmental stimuli?

    <p>Photoactive components</p> Signup and view all the answers

    What is the primary mechanism by which polymer-based carriers enhance the release of agrochemicals?

    <p>By facilitating ionic interactions</p> Signup and view all the answers

    What type of release pattern is exhibited by spinosyn from DACMC-CYS-Fe hydrogel at neutral and alkaline pH conditions?

    <p>Excellent sustained-release properties</p> Signup and view all the answers

    What effect does NIR irradiation have on the release of IMI from the PDA@PNIPAm nanosystem?

    <p>It increases the release rate significantly.</p> Signup and view all the answers

    How does the formulation of DACMC-CYS-Fe hydrogel respond to changes in pH?

    <p>It undergoes a sol-gel transition.</p> Signup and view all the answers

    What is a potential environmental concern regarding the long-term use of polymer-based carriers?

    <p>Unpredictable effects on the soil microenvironment</p> Signup and view all the answers

    Study Notes

    Stimuli-Responsive Hydrogels

    • CYS, or cysteine-based hydrogels, are versatile materials used in advanced biomedical applications. They have the ability to undergo conformational changes in response to environmental stimuli, such as fluctuations in pH and oxidative conditions. This characteristic makes them highly suitable for drug delivery systems, tissue engineering, and biosensing technologies. CYS hydrogels can be further modified to enhance their properties for specific applications., a type of hydrogel, serves as a foundational material in the development of an innovative hydrogel system that responds dynamically to changes in pH levels and redox conditions.
    • DACMC-CYS-Fe hydrogel represents a sophisticated advancement in biomaterials, integrating the properties of both carboxymethyl chitosan (CYS) and specific metal ions like iron (Fe3+). This hybrid structure not only enhances mechanical strength and stability but also introduces unique functionalities due to the ionic interactions formed with Fe3+. These interactions play a critical role in the hydrogel's ability to undergo reversible sol-gel transitions, enabling the hydrogel to react dynamically to environmental stimuli such as variations in pH and redox conditions. Consequently, the DACMC-CYS-Fe hydrogel can be effectively utilized in applications ranging from targeted drug delivery, where controlled release is essential, to tissue engineering, where responsiveness to physiological changes can promote cell growth and integration.hydrogel in presence of Fe3+ as a secondary crosslinking agent through ionic interactions
    • DACMC-CYS-Fe hydrogel exhibits a reversible sol–gel transition when exposed to pH and/or redox changes
    • DACMC-CYS-Fe shows excellent sustained-release properties under neutral and alkaline conditions (pH 6.8 or 7.4). Approximately 80% of spinosyn released after 18 days.
    • The release of Spinosyn is a naturally occurring compound that is derived from the fermentation of the bacterium Saccharopolyspora spinosa. It is widely known for its insecticidal properties and is utilized in agriculture as a biopesticide due to its effectiveness against a variety of pests while being minimally harmful to non-target organisms. Spinosyn acts on the nervous system of insects, disrupting their normal functioning and leading to paralysis or death. Its unique mechanism of action involves the interaction with nicotinic acetylcholine receptors, which is distinct from conventional insecticides, thus making it an important tool in integrated pest management strategies. Additionally, spinosyn is increasingly being investigated for its potential applications in veterinary medicine and for the control of certain agricultural pests, highlighting its versatility and the growing interest in sustainable agriculture practices.increases slightly with increasing temperature
    • At 50°C (pH = 6.8) the cumulative release of spinosyn after 18 days was approximately 89%.
    • Poly(N-isopropylacrylamide) with polydopamine (PDA) components nanosystem loaded with IMI exhibits good dual responsiveness to temperature and infrared light
    • At 25°C, 20% of Insecticide Mode of Action was released within 5 hours, while at 40°C, the sustained release was as high as 64% within 5 hours.
    • After 30 minutes of NIR irradiation, the cumulative release of IMI was 16%, almost 3 times that of no light irradiation (5.2%)
    • An l-infrared light and pH dual-responsive nanocomposite was prepared using graphene oxide (GO) and polydopamine (PDA) as carriers for loading oxamidil
    • Approximately 38%, 48% and 65% of oxamidil was released from the nanocomposite within 120 hours at pH 5, 7 and 9, respectively.
    • The release of oxamidil in the NIR irradiation was 10% higher than that in the non-irradiated group.
    • Polymer-based carriers can considerably enhance the use of agrochemicals
    • Silica nanoparticles have the advantages of easy synthesis and modification, excellent stability, and biocompatibility
    • Modified silica nanoparticles can effectively respond to pH, ionic strength, enzymes and redox reactions
    • The grafting of alginate (Alg) onto the silica surface via Ugi reaction makes the modified silica more sensitive to pH.
    • By increasing the pH from 3 to 8, the release of loaded pesticide (λ-cyhalothrin) in the alginate@silica carrier in 25% methanol–water mixture was sensitive to pH, and in alkaline environment, Aba@HMS@P(GMA-AA) swelled and resulted in a significant increase in the release.
    • At pH 10, the cumulative release of Aba increased to 87% on the 15th day under methanol–water mixture, about 6.5 times higher than the release at pH 5–7 under the same condition.
    • Porous polyethyleneimine-grafted lignin microspheres (PLM) were prepared by grafting polyethyleneimine onto lignin using PEG as a pore-forming agent through a reverse suspension copolymerization method
    • PLM, which stands for porous layered material, features a highly porous structure that is specifically designed to maximize surface area and enhance interaction with various substances. Coupled with its abundant functional groups, PLM exhibits remarkable adsorption capabilities that make it particularly effective for loading a range of agrochemicals. It has been reported to have an impressive adsorption capacity of 909.09 mg/g for the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), a common synthetic plant growth regulator. This high adsorption rate underscores the potential of PLM for applications in agriculture and environmental remediation.
    • PLM was used for the pH-responsive controlled release of 2,4-D.
    • MSNs-PDA-Cu nanoparticles were synthesized through a chemical chelation process that involved the interaction of copper ions (Cu2+) with mesoporous silica nanoparticles (MSNs) using dopamine as a ligand, facilitating the formation of stable nanocomposites with unique properties.
    • Aba@HMS@P(GMA-AA) is a specialized formulation that has been meticulously prepared for the efficient loading and subsequent release of the Aba insecticide. This process is crucial for ensuring that the insecticide is effectively deployed to combat pest populations, thereby enhancing agricultural productivity and promoting sustainable farming practices.
    • efficient loading and subsequent release of Aba insecticide, a vital component in pest management. This process involves careful handling and adherence to safety protocols to maximize the effectiveness of the insecticide while minimizing any potential environmental impact or risks to human health.
    • PLM (polymer-lipid microparticles) were prepared through the process of inverse suspension copolymerization, which involves forming tiny droplets of monomer in a continuous phase, allowing for controlled polymerization.

    Environmental Considerations

    • Polymer-based carriers are biodegradable when exposed to natural ultraviolet rays
    • Carriers can easily degrade into water and carbon dioxide under the action of soil microorganisms
    • The impact of the long-term use of polymer-based carriers needs to be considered
    • Unpredictable long-term consequences on the structure of soil microbial populations and the effects on plants and their microenvironment should be taken into account
    • The potential for scaling up the application of carriers in farm lands still needs to be further elaborated
    • The content of organic acids, phenolic acids and other substances in the soil change which results in pH changes in the surrounding environment of crops
    • This can be used to release agrochemicals to promote crop growth

    References and Outlook

    • Stimuli-responsive polymers: Biomedical applications and challenges for clinical translation, Adv. Drug Deliv. 65 (2013) 10–16.
    • Plant Growth Regulators: Backgrounds and Uses in Plant Production, J. Plant Growth Regul. 34 (4) (2015) 845–872.
    • Gibberellin Promotes Shoot Branching in the Perennial Woody Plant Jatropha curcas, Plant Cell Physiol. 56 (8) (2015) 1655–1666.
    • Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals, Front. Plant Sci. 9 (2018) 668.
    • Dissipation and Enantioselective Degradation of Plant Growth Retardants Paclobutrazol and Uniconazole in Open Field, Technol. 16 (10) (2019) 6135–6144.

    Controlled Release Systems

    • Spinosyn release from a hydrogel is sustained in neutral and alkaline environments (pH 6.8 and 7.4).
    • The spinosyn release rate increases with temperature.
    • Imidacloprid (IMI) release is triggered by temperature and infrared light.
    • Oxamidil release from a nanocomposite is pH- and infrared light-responsive.
    • Silica nanoparticles modified with alginate are pH-sensitive, releasing lambda-cyhalothrin upon pH changes.
    • Abscisic acid (Aba)-loaded silica nanoparticles are pH-sensitive, releasing more Aba at higher pH.
    • Polyethyleneimine-grafted lignin microspheres (PLM) are designed for controlled release of 2,4-dichlorophenoxyacetic acid (2,4-D).

    Environmental Considerations

    • Polymer-based carriers can degrade under natural UV light and be broken down by soil microorganisms.
    • The long-term impact of polymer-based carrier use on soil microbial populations and plants needs further analysis.

    Promising Applications

    • Stimuli-responsive polymers have biomedical applications and potential in clinical translation.
    • Plant growth regulators have a variety of applications in plant production.
    • Gibberellin promotes branching in plants.
    • Abscisic acid/gibberellin balance influences seed dormancy and germination.
    • Plant growth retardants (e.g., paclobutrazol, uniconazole) dissipate and degrade in the field.
    • Agrochemicals can be released using pH-sensitive systems to promote crop growth.

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    Description

    This quiz explores the properties and applications of stimuli-responsive hydrogels, focusing on the DACMC-CYS-Fe and PDA@P-NIPAm nanosystems. It covers their responsiveness to pH, temperature, and infrared light in drug release mechanisms. Test your understanding of these advanced materials and their functional capabilities.

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