Temporally Programmed Hydrogelation of a Short Peptide Charge Transfer Complex Tanushree Das, Saurav Das, Malay Kumar Baroi, Subhadeep Sen, Debapratim Das, Rumana Parveen Langmuir, 2026 Creating artificial systems that emulate the dynamic behavior of living assemblies remains a central goal in supramolecular chemistry. Here, a charge transfer-driven pH clock-regulated hydrogelation process is presented, arising from the interaction between a pyrene-lysine cysteine tripeptide (PyKC) and a phenylalanine-substituted naphthalene diimide (NDIF). Spectroscopic and structural analyses confirmed the formation of a 1:1 donor-acceptor complex organized through π-π stacking and β-sheet arrangements. The resulting hydrogel forms rapidly under alkaline conditions and exhibits reversible transitions triggered by variations in temperature and pH. Coupling the system with a Tris buffer-glucono-δ-lactone pH clock produces transient hydrogelation with lifetimes precisely tunable by the activator-deactivator ratio. The hydrogel repeatedly assembles and disassembles in synchrony with pH oscillations, maintaining its structural integrity.
Non-Plasmonic Oxidase-Like Gold Nanocatalysts on Hydrogel Beads for Broad-Spectrum Water Decontamination Tanushree Das, Maitery Yadav, Saurav Das, Gargi Mondal, Sunanda Chatterjee, Debapratim Das Langmuir, 2025 The efficient and sustainable remediation of contaminated water calls for catalytic systems that must clean broadly, endure widely, and last repeatedly. In this regard, we report the development of sulfonate-functionalized core–shell hydrogel beads embedded with in situ synthesized gold nanoparticles (AuNPs) that exhibit intrinsic oxidase-like activity without requiring external light or chemical oxidants. The sulfonate ligands modulate the surface electronic environment of the AuNPs, facilitating singlet oxygen generation via a nonplasmonic, radiationless mechanism. These AuNPs, confined to the bead surface, provide rapid substrate access, eliminating diffusion barriers and enabling efficient catalytic oxidation of a broad spectrum of contaminants. The AuNP@Beads demonstrate excellent activity toward phenolic pollutants, azo dyes, and biologically relevant catecholamines such as dopamine and epinephrine. They also exhibit potent antibacterial efficacy against both Gram-negative and Gram-positive pathogens through ROS generation. The catalytic beads are reusable, structurally stable under ionic stress, and show negligible nanoparticle leaching. Furthermore, the treated wastewater supports healthy plant growth, underscoring its environmental compatibility. This study introduces a robust, multifunctional catalytic platform for water purification that combines oxidase-like catalysis, antibacterial action, and biosensing potential. The light-independent operation and broad-spectrum efficacy make it highly promising for real-world environmental remediation applications.
Time-Encoded Information Encryption with pH Clock Guided Broad-Spectrum Emission by Dynamic Assemblies Priyam Das, Tanushree Das, Suprotim Koley, Malay Kumar Baroi, Saurav Das, Jyotirmayee Mohanty, Debapratim Das Angewandte Chemie International Edition, 2025 With growing threats from counterfeiting‐based security breaches, multi‐level and specific stimuli‐responsive anti‐counterfeiting devices and message encryption methods have attracted immense research interest. Fluorescence‐based encryption from aggregation‐induced emission (AIE)‐based materials solves the problems to a considerable extent. However, the development of smarter patterns with hierarchical security levels alongside dynamic display is still challenging. To screen out this complication, we bring forward a pH‐switchable fluorescent assembly of an AIEgen and an aliphatic acid. We later temporally direct the molecular assembly with the aid of a chemical trigger‐regulated pH clock, generating a transitory multicolor emission, including transient white light generation. The pH‐dependent emissions were further implemented in constructing smart multi‐input fluorescent chemical AND gates. Subsequently, we integrate the time‐gated emissive system to develop an advanced multi‐dimensionally secure data encryption strategy. This novel approach enhances anti‐counterfeiting measures by introducing an additional layer of security based on temporal characteristics.
pH Clock Guided Dynamic Broad Spectrum Multi-Color Fluorescence Modulation in Size-Oscillatory Vesicles Saurav Das, Tanushree Das, Shreya Debnath, Oren A. Scherman, Debapratim Das Advanced Optical Materials, 2024 Acid–base equilibria of aqueous cellular fluids play a vital role in constituting various signaling and feedback mechanisms in biological systems. To mimic the complex pH‐directed signaling mechanism in laboratory settings, a pH‐responsive vesicular assembly is presented that shows dynamic multicolor fluorescence and size alterations under the influence of a chemically driven pH cycle. The vesicular architecture is a versatile platform for establishing Förster resonance energy transfer (FRET) interactions between multiple donors and acceptor fluorophores. Spontaneously fluctuating interfacial charge of the vesicles during the pH cycle alters the donor fluorophore's emission intensity, affecting the efficiency of FRET interactions among the donor–acceptor pairs. This enables multicolor as well as transient pure white light fluorescence of the vesicles during the pH cycle. The vesicles also display significant size changes in response to varying pH conditions. Furthermore, the vesicles demonstrate excellent adaptability in terms of the lifespan of the oscillatory cycles and the tunability of the fluorescence color transitions.
Cumulative Effect of pH and Redox Triggers on Highly Adaptive Transient Coacervates Sumit Chowdhuri, Saurav Das, Ritvika Kushwaha, Tanushree Das, Basab Kanti Das, Debapratim Das Chemistry A European Journal, 2023 An intricate synergism between multiple biochemical processes and physical conditions determines the formation and function of various biological self‐assemblies. Thus, a complex set of variables dictate the far‐from‐equilibrium nature of these biological assemblies. Mimicking such systems synthetically is a challenging task. We report multi‐stimuli responsive transient coacervation of an aldehyde‐appended polymer and a short peptide. The coacervates are formed by the disulphide linkages between the peptide molecules and the imine bond between the polymer and the peptide. Imines are susceptible to pH changes and the disulphide bonds can be tuned by oxidation/reduction processes. Thus, the coacervation is operational only under the combined effect of appropriate pH and oxidative conditions. Taking advantage of these facts, the coacervates are transiently formed under a pH cycle (urea‐urease/gluconolactone) and a non‐equilibrium redox cycle (TCEP/H2O2). Importantly, the system showed high adaptability toward environmental changes. The transient existence of the coacervates can be generated without any apparent change in size and shape within the same system through the sequential application of the above‐mentioned nonequilibrium reaction cycles. Additionally, the coacervation allows for efficient encapsulation/stabilisation of proteins. Thus, the system has the potential to be used for protein/drug delivery purposes in the future.
Mannose-Decorated Composite Peptide Hydrogel with Thixotropic and Syneresis Properties and its Application in Treatment of Leishmaniasis Payel Dowari, Shalini Roy, Saurav Das, Sumit Chowdhuri, Ritvika Kushwaha, Basab K. Das, Anindita Ukil, Debapratim Das Chemistry an Asian Journal, 2022 Leishmaniasis, caused by the intramacrophage protozoan parasite Leishmania donovani, is a life‐threatening yet neglected vector‐borne disease. Few medications for the treatment of this disease are available. However, targeted delivery of drugs to macrophages remains a significant concern. Macrophages are equipped with many receptors, and therefore putting suitable ligands in the macrophage targeting drug delivery vehicle gained a lot of attention. One such receptor is the mannose receptor, abundantly expressed by macrophages. To treat this deadly disease, in this study, a mannose containing composite hydrogel is prepared by combining a self‐aggregating short peptide (Nap‐FFGE‐NH2, Pep‐A) and a mannose containing non‐aggregating peptide (Nap‐FF‐mannosyl, Pep‐B). The self‐aggregation of the composite hydrogel is evaluated using various spectroscopic and microscopic techniques. Intermolecular hydrogen bonding and π‐π stacking lead to an antiparallel β‐sheet like arrangement of the peptides. Notably, the composite hydrogel showed shear‐thinning and syneresis properties. Moreover, the composite hydrogel was found to be stable in cell‐culture media, biodegradable and non‐toxic to the macrophages. Both control and infected macrophages showed effective cell growth and proliferation when subjected to the composite 2D and 3D hydrogel matrix. When treated with Amphotericin B loaded composite hydrogel, the drug was effectively delivered to kill the parasite in the infected macrophages. Almost 3.5 fold decrease in the parasite burden was recorded when infected cells were treated with drug‐loaded composite hydrogel. The injectability, biodegradability, non‐cytotoxicity, and efficient drug delivery properties of the mannose‐functionalized hydrogel make it a suitable candidate for the treatment of Leishmaniasis.
Temporally Programmed Hydrogelation of a Short Peptide Charge Transfer Complex T Das, S Das, MK Baroi, S Sen, D Das, R Parveen Langmuir 42 (8), 6512-6520 , 2026 2026 Citations: 2
Non-Plasmonic Oxidase-Like Gold Nanocatalysts on Hydrogel Beads for Broad-Spectrum Water Decontamination T Das, M Yadav, S Das, G Mondal, S Chatterjee, D Das Langmuir 41 (37), 25439-25453 , 2025 2025 Citations: 2
In situ fabricated gold nanostars on hydrogel beads as photo-oxidase mimics for rapid and sustainable POCT of uric acid T Das, S Das, D Das Journal of Materials Chemistry B 13 (3), 1079-1088 , 2025 2025 Citations: 7
pH Clock Guided Dynamic Broad Spectrum Multi‐Color Fluorescence Modulation in Size‐Oscillatory Vesicles S Das, T Das, S Debnath, OA Scherman, D Das Advanced Optical Materials 12 (4), 2301422 , 2024 2024 Citations: 6
Time‐Encoded Information Encryption with pH Clock Guided Broad‐Spectrum Emission by Dynamic Assemblies D Das, P Das, T Das, S Koley, MK Baroi, S Das, J Mohanty Angewandte Chemie, e202414239 , 2024 2024 Citations: 27
Fabrication of core–shell beads, hollow capsules, and AuNP-embedded catalytic beads from an ultrasmall peptide hydrogel T Das, S Das, D Das Chemical Engineering Journal 477, 147105 , 2023 2023 Citations: 9
Cumulative Effect of pH and Redox Triggers on Highly Adaptive Transient Coacervates S Chowdhuri, S Das, R Kushwaha, T Das, BK Das, D Das Chemistry–A European Journal 29 (24), e202203820 , 2023 2023 Citations: 20
Mannose‐Decorated Composite Peptide Hydrogel with Thixotropic and Syneresis Properties and its Application in Treatment of Leishmaniasis P Dowari, S Roy, S Das, S Chowdhuri, R Kushwaha, BK Das, A Ukil, ... Chemistry–An Asian Journal 17 (18), e202200550 , 2022 2022 Citations: 11
Development of a hydrolase mimicking peptide amphiphile and its immobilization on silica surface for stereoselective and enhanced catalysis P Dowari, MK Baroi, T Das, BK Das, S Das, S Chowdhuri, A Garg, ... Journal of colloid and interface science 618, 98-110 , 2022 2022 Citations: 24
Bi-directional feedback controlled transience in Cucurbituril based tandem nanozyme S Das, P Das, P Dowari, BK Das, D Das Journal of colloid and interface science 614, 172-180 , 2022 2022 Citations: 26
Proline selective labeling via on-site construction of naphthoxazole (NapOx) SK Roy, A Purkait, R Shome, S Das, D Das, SS Ghosh, CK Jana Chemical Communications 58 (39), 5909-5912 , 2022 2022 Citations: 3
Controlling the lifetime of cucurbit [8] uril based self-abolishing nanozymes S Das, T Das, P Das, D Das Chemical Science 13 (14), 4050-4057 , 2022 2022 Citations: 23
Rational design of peptide-based smart hydrogels for therapeutic applications S Das, D Das Frontiers in Chemistry, 980 , 2021 2021 Citations: 98
Aggregation‐directed High Fidelity Sensing of Picric Acid by a Perylenediimide‐based Luminogen B Pramanik, S Das, D Das Chemistry–An Asian Journal 15 (24), 4291-4296 , 2020 2020 Citations: 23
Smart thixotropic hydrogels by disulfide-linked short peptides for effective three-dimensional cell proliferation S Chowdhuri, A Saha, B Pramanik, S Das, P Dowari, A Ukil, D Das Langmuir 36 (50), 15450-15462 , 2020 2020 Citations: 27
Ultrafast, Highly Sensitive, and Selective Detection of p -Xylene at Room Temperature by Peptide-Hydrogel-Based Composite Material N Singha, S Neogi, B Pramanik, S Das, A Dasgupta, R Ghosh, D Das ACS Applied Polymer Materials 1 (9), 2267-2272 , 2019 2019 Citations: 35
Freeze the dynamicity: charge transfer complexation assisted control over the reaction pathway N Singha, BK Das, B Pramanik, S Das, D Das Chemical Science 10 (43), 10035-10039 , 2019 2019 Citations: 23
pH clock instructed transient supramolecular peptide amphiphile and its vesicular assembly P Dowari, S Das, B Pramanik, D Das Chemical Communications 55 (94), 14119-14122 , 2019 2019 Citations: 42
Aggregation dependent fluorescence switching in benzothiazole derivative based H-bonded mesogen BB Chakraborty, S Anwar, S Das, SB Paul, G Mohiuddin, J De, ... Liquid Crystals 45 (11), 1644-1653 , 2018 2018 Citations: 24
MOST CITED SCHOLAR PUBLICATIONS
Rational design of peptide-based smart hydrogels for therapeutic applications S Das, D Das Frontiers in Chemistry, 980 , 2021 2021 Citations: 98
pH clock instructed transient supramolecular peptide amphiphile and its vesicular assembly P Dowari, S Das, B Pramanik, D Das Chemical Communications 55 (94), 14119-14122 , 2019 2019 Citations: 42
Ultrafast, Highly Sensitive, and Selective Detection of p -Xylene at Room Temperature by Peptide-Hydrogel-Based Composite Material N Singha, S Neogi, B Pramanik, S Das, A Dasgupta, R Ghosh, D Das ACS Applied Polymer Materials 1 (9), 2267-2272 , 2019 2019 Citations: 35
Time‐Encoded Information Encryption with pH Clock Guided Broad‐Spectrum Emission by Dynamic Assemblies D Das, P Das, T Das, S Koley, MK Baroi, S Das, J Mohanty Angewandte Chemie, e202414239 , 2024 2024 Citations: 27
Smart thixotropic hydrogels by disulfide-linked short peptides for effective three-dimensional cell proliferation S Chowdhuri, A Saha, B Pramanik, S Das, P Dowari, A Ukil, D Das Langmuir 36 (50), 15450-15462 , 2020 2020 Citations: 27
Bi-directional feedback controlled transience in Cucurbituril based tandem nanozyme S Das, P Das, P Dowari, BK Das, D Das Journal of colloid and interface science 614, 172-180 , 2022 2022 Citations: 26
Development of a hydrolase mimicking peptide amphiphile and its immobilization on silica surface for stereoselective and enhanced catalysis P Dowari, MK Baroi, T Das, BK Das, S Das, S Chowdhuri, A Garg, ... Journal of colloid and interface science 618, 98-110 , 2022 2022 Citations: 24
Aggregation dependent fluorescence switching in benzothiazole derivative based H-bonded mesogen BB Chakraborty, S Anwar, S Das, SB Paul, G Mohiuddin, J De, ... Liquid Crystals 45 (11), 1644-1653 , 2018 2018 Citations: 24
Controlling the lifetime of cucurbit [8] uril based self-abolishing nanozymes S Das, T Das, P Das, D Das Chemical Science 13 (14), 4050-4057 , 2022 2022 Citations: 23
Aggregation‐directed High Fidelity Sensing of Picric Acid by a Perylenediimide‐based Luminogen B Pramanik, S Das, D Das Chemistry–An Asian Journal 15 (24), 4291-4296 , 2020 2020 Citations: 23
Freeze the dynamicity: charge transfer complexation assisted control over the reaction pathway N Singha, BK Das, B Pramanik, S Das, D Das Chemical Science 10 (43), 10035-10039 , 2019 2019 Citations: 23
Cumulative Effect of pH and Redox Triggers on Highly Adaptive Transient Coacervates S Chowdhuri, S Das, R Kushwaha, T Das, BK Das, D Das Chemistry–A European Journal 29 (24), e202203820 , 2023 2023 Citations: 20
Mannose‐Decorated Composite Peptide Hydrogel with Thixotropic and Syneresis Properties and its Application in Treatment of Leishmaniasis P Dowari, S Roy, S Das, S Chowdhuri, R Kushwaha, BK Das, A Ukil, ... Chemistry–An Asian Journal 17 (18), e202200550 , 2022 2022 Citations: 11
Fabrication of core–shell beads, hollow capsules, and AuNP-embedded catalytic beads from an ultrasmall peptide hydrogel T Das, S Das, D Das Chemical Engineering Journal 477, 147105 , 2023 2023 Citations: 9
In situ fabricated gold nanostars on hydrogel beads as photo-oxidase mimics for rapid and sustainable POCT of uric acid T Das, S Das, D Das Journal of Materials Chemistry B 13 (3), 1079-1088 , 2025 2025 Citations: 7
pH Clock Guided Dynamic Broad Spectrum Multi‐Color Fluorescence Modulation in Size‐Oscillatory Vesicles S Das, T Das, S Debnath, OA Scherman, D Das Advanced Optical Materials 12 (4), 2301422 , 2024 2024 Citations: 6
Proline selective labeling via on-site construction of naphthoxazole (NapOx) SK Roy, A Purkait, R Shome, S Das, D Das, SS Ghosh, CK Jana Chemical Communications 58 (39), 5909-5912 , 2022 2022 Citations: 3
Temporally Programmed Hydrogelation of a Short Peptide Charge Transfer Complex T Das, S Das, MK Baroi, S Sen, D Das, R Parveen Langmuir 42 (8), 6512-6520 , 2026 2026 Citations: 2
Non-Plasmonic Oxidase-Like Gold Nanocatalysts on Hydrogel Beads for Broad-Spectrum Water Decontamination T Das, M Yadav, S Das, G Mondal, S Chatterjee, D Das Langmuir 41 (37), 25439-25453 , 2025 2025 Citations: 2