Current strategies for treating bacterial infections primarily rely on antibiotics, with only limited follow-up monitoring to verify that all bacteria have been eradicated. This limitation has driven research toward the development of advanced biomaterials with dual capabilities of antibacterial activity and bacterial detection. Functionalized hydrogels, with their architecturally dynamic and stimulus-responsive frameworks, have emerged as fundamental materials in biomedicine and adaptive sensing. Herein, we report a cost-effective, one-step synthesis of an Aggregation-Induced Emission (AIE)-active hydrogel through the covalent functionalization of chitosan (Ch) with 1-pyrenecarboxaldehyde (1-PCA), forming an injectable, self-healing biomaterial (ChPCA) with inherent luminescent properties through a heat-to-cool transition. The simplicity and affordability of this technique make it highly promising for future scalability and practical applications in advanced material development. Beyond structural characterization using FTIR, PXRD, TGA, FESEM, and contact angle analyses, density functional theory (DFT) calculations elucidate critical parameters for gel stability. Furthermore, the hydrogel shows potent antibacterial activity against S. aureus (Gram-positive) and E. coli (Gram-negative) bacterial strains without requiring additional antibiotics. This activity is attributed to its membrane-targeting mechanism, which is further confirmed through SEM analysis. The inherent AIE effect facilitates real-time bacterial detection, with preferential accumulation on microbial membranes leading to cell membrane disruption and intracellular penetration. This study introduces a versatile, antibiotic-free strategy for fighting against pathogenic bacterial strains, and it also provides a scalable framework for developing next-generation biomaterials with significant potential in both bacterial detection and therapeutic applications.

Protein misfolding and aggregation are central to many protein aggregation disorders, highlighting the need for effective aggregation inhibitors. This study investigated fructose-induced aggregation of hen egg-white lysozyme (HEWL) and its modulation by the phenolic acids ferulic acid (FA), caffeic acid (CA) and chlorogenic acid (CGA) at 100 and 200 μM. Circular dichroism and ThT fluorescence assays showed that fructose promoted aggregation through increased β-sheet content and fluorescence intensity, respectively, whereas all phenolic acids suppressed β-sheet formation. CA displayed the highest aggregation inhibition activity, followed by FA and CGA. FESEM imaging confirmed fructose-induced HEWL aggregation without fibril formation and demonstrated disruption of aggregates in the presence of phenolic acids. These findings were explained by other biophysical characterisation studies. Fluorescence spectroscopy indicated a static quenching mechanism for all complexes, with FA and CA displaying atypical quenching behaviour. Binding constants suggested moderate affinity, with CA (4.11 ± 0.57 × 104 M-1 at 300 K) showing the strongest interaction. +ΔS and +ΔH indicated hydrophobic interactions as the main stabilising force for all complexes, while computational studies revealed additional H-bonding interactions within aggregation-prone regions (K-peptide) of HEWL. Together, experimental and computational findings demonstrate that these phenolic acids effectively modulate HEWL aggregation by stabilising native-like conformations and disrupting aggregate formation.

Abstract DNA, the fundamental genetic material in living organisms, is of great scientific interest due to its biological role and interactions with small molecules. Ultraviolet (UV) radiation poses a substantial environmental risk by inducing DNA damage, potentially leading to mutagenesis and skin cancers. The study investigated purpurin interaction with ct-DNA and its protective effect against UV-induced DNA damage. UV exposure caused significant DNA damage, indicated by 36% reduced absorbance; however, purpurin significantly lessened this damage to only 19%. In addition, Raman spectra showed no significant changes in purpurin-treated DNA, indicating that the DNA’s native structure was preserved, suggesting that purpurin is able to protect the DNA against UV-induced DNA damage. UV–vis and cyclic voltammetry studies indicated purpurin-ct-DNA complex formation with a binding constant of 104 M–1. Thermodynamic analysis shows negative ΔH [-(39.91 ± 0.77) kJ mol–1] and ΔS [-(51.68 ± 2.70) J mol–1], indicating hydrogen bonding and van der Waals forces, with negative ΔG confirming spontaneity. Groove binding is the preferred binding mode as evaluated by various experimental techniques. Circular dichroism (CD) and Fourier-transform infrared (FT-IR) spectra suggested that purpurin binding does not alter DNA’s structural integrity. Molecular dynamics (MD) simulation further supported the structural stability and flexibility of DNA. These findings provide mechanistic insight into the interaction of purpurin with DNA and its potential role in maintaining DNA structural integrity under UV irradiation.

Conventional rigid electronic components often suffer from mechanical mismatch with soft biological tissues, resulting in discomfort, unstable signals, and mechanical failure under repeated deformation. To address these challenges, we present a sprayable bio-inspired hydrogel (SOPB) synthesized from okra mucilage, polyvinyl alcohol, and borax, with NaCl incorporation to enhance ionic conductivity. This hydrogel shows strong adhesion, injectability, stretchability, transparency, self-healing capability, passive thermal regulation, conductivity, and antibacterial activity against Escherichia coli and Staphylococcus aureus-a rare combination of properties within a single material platform. Its porous, water-rich network promotes efficient ion transport, while its conductivity enables stable electrochemical signaling, making it highly suitable for biosensor applications. Remarkably, the hydrogel performed comparably to commercial electrodes in surface electromyography (sEMG) and electrocardiography (ECG) measurement using Shimmer3 device. We fabricated a low-cost, multilayered hydrogel-based device (OKPVD device) capable of monitoring various human motions (finger, knee, and wrist bending, as well as tapping and walking) and detecting different emotional states, such as different facial expressions. Beyond sensing, the hydrogel's adaptability underscores its potential for wearable bioelectronics and skin-friendly E-skindevices. This work presents a facile sprayable fabrication route that integrates biomedical engineering, soft electronics, and human-machine interfaces for healthcare and rehabilitation.

Due to increase in demands of excellent optical properties, the development of blue-emitting materials for light emitting diode (LED) and sensing applications become significant. Here we have mainly reported the synthesis of blue light emitting ZnSe core and ZnSe/CdSe core-shell QDs capped with N-Acetyl-L-Cysteine (NAC) by a simple one pot hydrothermal method. The elemental composition of the ZnSe and ZnSe/CdSe QDs can be revealed by XPS (binding energy) and EDX analysis. The small sized (∼ 4.65 ± 0.25 nm) cubic core-shell QD is highly suitable for sensitive and selective detection of nitroaromatic compound picric acid with a low limit of detection (LOD) value 1.04 ± 0.15 μM via fluorescence quenching methods. The production of reliable and affordable phosphor converted blue LEDs has been made possible by the effective application of this blue light emitting ZnSe/CdSe QDs due to its better stability and color purity upto ∼77% for low-cost LED based devices in future.

This study examines the interaction between ovalbumin (OVA) and two coumarin derivatives, esculin and esculetin, using spectroscopic and computational methods. Fluorescence quenching confirmed a static mechanism, with binding constants (Kb) in the range of 1.776-3.340 × 104 M-1 for esculetin and 1.198-3.870 × 104 M-1 for esculin across 291-308 K. The binding affinity increased in the presence of Cu2+ and Zn2+ and was enhanced under acidic conditions. Thermodynamic analysis revealed that OVA-esculetin interaction is driven by hydrophobic forces and hydrogen bonding (ΔH = +31.18 kJ mol-1, ΔS = +188.06 J mol-1 K-1, ΔG = - 24.86 kJ mol-1), whereas OVA-esculin binding is dominated by hydrogen bonding and van der Waals interactions (ΔH = -53.09 kJ mol-1, ΔS = -93.21 J mol-1 K-1, ΔG = - 25.31 kJ mol-1). Spectroscopic analyses (synchronous, 3D fluorescence, CD, and FT-IR) indicated conformational and microenvironmental changes in OVA upon ligand binding. Thermal studies showed that esculetin enhanced protein stability (Tm = 72.01 °C), while esculin reduced it (Tm = 60.14 °C). ThT and Congo Red assays, supported by fluorescence microscopy, confirmed inhibition of OVA fibrillation. Molecular docking and MD simulations validated the experimental data, showing stable binding of esculin and esculetin within the OVA binding cavity.

A protein corona formed on the surface of engineered nanostructures alters their biological identity as they are introduced to body fluids. In this paper, we engineered naturally occurring polyphenol, catechin-capped bimetallic Ag-Au nanoparticles as well as their respective monometallic forms and investigated the formation of protein corona taking human serum albumin (HSA) as a model carrier protein. The comparative nature of binding, affinity of HSA toward the catechin-capped bimetallic and monometallic silver and gold nanoparticles, was analyzed with a number of photophysical experiments. The binding interaction of HSA with these polyphenol-capped NPs was driven spontaneously via electrostatic interactions, where structural conformations of HSA remained intact after complexation. Isothermal titration calorimetry and steady state fluorescence analysis revealed the higher binding efficacy of HSA toward bimetallic AgAuNPs than the monometallic Cat-AuNPs and Cat-AgNPs. The formation of the protein corona of HSA on these polyphenol-capped NPs dramatically enhanced the drug loading capacity. The HSA-coronated bimetallic AgAuNPs showed the highest loading percentage of doxorubicin (DOX) (94.64 ± 1.47%) and thereby a higher release percentage (84.37%) at pH 4.6 than that with monometallic Cat-AuNPs and Cat-AgNPs. The release kinetic analysis of doxorubicin from the HSA-coronated Cat-AgAuNPs system supported the non-Fickian diffusion mechanism, i.e., drug release via swelling, erosion, or degradation of the carrier system. The DOX-loaded HSA-coronated catechin-capped NPs showed enhanced cell cytotoxicity against the A549 lung cancer cell line, among which Cat-AgAuNPs showed the highest reduction in cell viability as revealed by the MTT assay and the cytomorphological changes visualized by optical microscopic imaging.

Oxidative damage to DNA has significant consequences for human health and is identified as one of the key contributors to the onset and advancement of several diseases. Therefore, it is crucial to prevent oxidatively driven DNA lesions in both humans and other organisms. This study investigated the potential of daphnetin to protect DNA from oxidative damage and its binding interaction with calf thymus DNA (ct-DNA) employing multispectroscopic techniques, viscosity measurements, gel electrophoresis, docking studies, and molecular dynamics (MD) simulation. The 2-thiobarbituric acid (TBA) colorimetry assay and agarose gel electrophoresis demonstrated that daphnetin acted to protect the deoxyribose sugar and the backbone of the double-stranded DNA structure from damage caused by hydroxyl radicals. Moreover, various in vitro antioxidant assays (DPPH·,·OH, and O2·-) revealed scavenging activity comparable to that of the antioxidant ascorbic acid, providing insight into the mechanism of DNA protection. UV-vis, fluorescence studies confirmed the complex formation between ct-DNA and daphnetin, with a binding constant on the order of 103 M-1, suggesting a weak binding affinity. Competitive displacement assay, thermal denaturation studies, and viscosity measurements indicated groove binding, further supported by molecular docking studies. Furthermore, MD simulation studies confirmed a stable binding of daphnetin with DNA without compromising the structural integrity of DNA.

Surface-functionalized quantum dots (QDs) have garnered significant attention in recent years for a variety of applications, including LEDs, photovoltaics, sensing, bioimaging and biomedical domains due to their distinct optical features such as strong photoluminescence behavior, high quantum yields etc. However, formation of nontoxic QDs is very challenging for the researchers because of their lower optical properties as compared to Cd based QDs. The phenomenon of doping in semiconductor QDs is an effective way to achieve high opto-electrical properties in the host QDs. We have presented a low temperature colloidal synthesis of CuS QDs using cobalt (Co2+) as a doping agent with an exceptional stability at room temperature for 30 days. The photoluminescence (PL) properties of Co2+-doped CuS QDs exhibit a deep-blue emission at 420 nm resulting in excellent optical property with an improvement of photoluminescence quantum yield. Due to remarkable CIE chromaticity coordinates, good CCT values, and high colour purity, the synthesized Co2+-doped CuS QDs could be used extensively in LEDs and prove to be useful as blue phosphors. The synthesized Co2+-doped CuS QDs also act as a fluorescence probe in the detection of ferric ion (Fe3+) with high sensitivity, good selectivity, a low limit of detection (LOD) and limit of quantification (LOQ), of (4.99 +/- 0.12) mu M and (16.67 +/- 0.40) mu M, respectively.

Carbon nanotubes (CNTs) have potential applications in various biomedical and biotechnological fields, importance of protein-CNTs interactions in living cells, as well as their concerns about the nanotoxicity of these CNTs, have not been well investigated. This study examines by experimentally human serum albumin (HSA) interaction with different surface functionalized multi-walled carbon nanotubes (MWCNTs). The adsorption was done on HSA onto 1,2-propanediol functionalized MWCNTs (MWCNTs-OH) and cysteamine functionalized MWCNTs (MWCNTs-SH) and estimates the corresponding adsorption parameters. During the adsorption process, pristine MWCNTs (p-MWCNTs) exhibit a higher adsorption capacity compared to MWCNTs-OH and MWCNTsSH, with the order being: p-MWCNTs > MWCNTs-SH > MWCNTs-OH. Here also Isothermal Titration Calorimetry (ITC) experiments were employed to analyze the interaction of HSA onto MWCNTs-OH and MWCNTs-SH. The possible binding parameters were indicated that HSA forms complexes with MWCNTs-OH and MWCNTsSH at specific nearby binding sites. And anti-fibrillation activity of surface functionalized MWCNTs was assessed using Thioflavin T (ThT) and Congo Red (CR) spectroscopic techniques, the secondary conformational changes were observed through circular dichroism (CD) experiments, additionally, the inhibitory role of surface functionalized MWCNTs in HSA fibril formation was confirmed through microscopic evaluations.

Engineering nanomaterials with products isolated from natural resources is attractive for targeted therapeutic applications. Prior to the biomedicinal applications, one significant facet of nanoparticles is the understanding of protein corona formation and its relative binding aspects. In this perspective, we have synthesized two different silver nanoparticles, one with the extract of the leaves of a traditional herb Clerodendrum colebrookianum, commonly known as "Nefafu", and the other with one of its major polyphenolic compounds, apigenin, and their complexations were studied with the model protein human serum albumin (HSA). The formation of the protein corona of HSA on the surface of AgNPs was revealed from the observed changes in terms of hydrodynamic size, ξ-potential, and LSPR band positions, and the gray colored layer of diameter ∼3 nm on the surface of AgNPs as visualized in the TEM micrographs. The combined multispectroscopic approaches and molecular dynamics simulation studies on the interaction process revealed the moderate binding affinities (Kb in the order of 104 M-1) of both the AgNPs toward HSA, where their complexations were found to be entropy driven with the involvement of hydrophobic association as the major driving force of interactions. Interestingly, both Nefafu-AgNPs and Apigenin-AgNPs could retain the secondary structural conformation of HSA. These polyphenol-capped NPs were able to significantly inhibit the fibrillation of HSA, where Nefafu-AgNPs with a higher number of polyhydroxy groups showed better inhibition than Apigenin-AgNPs, as revealed from the kinetic study with ThT assay, CR assay, ANS assay, circular dichroism, as well as from the morphological changes from amyloid-sheet structure to small globular units as visualized in fluorescence microscopic imaging.

Recent times have witnessed revolutionary progress in the design and development of functionalized nanomaterials as promising tools for biomedicinal applications. However, the gap in the fundamental understanding of the "biological responses" of the nanomaterials after the formation of "protein-corona" when it is exposed to the body system has drawn a thin line from its discoveries to real clinical trial. In this article we have synthesized two different silver NPs capped with the polyphenols of Psidium guajava (guava) leaf extract and the other with one of its major polyphenolic groups, morin. Then, the formation of "bio-nano interface" of these synthesized AgNPs were illustrated in detail by taking the model carrier protein hen egg white lysozyme (HEWL). The formation of protein corona of HEWL on the surface of the AgNPs was revealed by the increase in the hydrodynamic size and the negative ξ-potential values as well as from the visualization of an ∼1 nm thick light gray layer of HEWL in the TEM micrographs. The binding interaction of surface adsorbed HEWL with the AgNPs was analyzed with various photophysical and molecular dynamics simulation (MD) techniques. HEWL interacted with these polyphenol-assisted AgNPs with moderate binding affinity (Kb ∼ 104 M-1) in a spontaneous manner with the structural integrity in its native conformation. Though several covalent forces are responsible for protein-NP interaction, electrostatic and hydrophobic forces of attraction played the major role in the complexation of HEWL with Guava L.-AgNPs and Morin-AgNPs, respectively. The lysozyme protein-corona on the synthesized polyphenol-assisted AgNPs altered their biological response as revealed from the reduction of antibacterial activity against pathological Gram-positive (E. faecalis) as well as Gram-negative (E. coli) bacterial strains in vitro.

Multi-spectroscopic and computational techniques were utilized to investigate the interaction between daphnetin and pepsin, the principal gastric protease, along with daphnetin's inhibitory effect on pepsin aggregation. Fluorescence and UV-vis absorption spectral analyses indicated that daphnetin binds to pepsin via static quenching. Thermodynamic analyses revealed positive ΔH° [+(9.314 ± 1.018) kJ mol-1] and ΔS° [+(115.487 ± 3.154) J mol-1] values, indicating the presence of hydrophobic forces, while the negative ΔG° suggests the spontaneous formation of the complex. CD and FT-IR analyses demonstrated a substantial alteration in the secondary structure of pepsin upon daphnetin binding. Daphnetin can inhibit pepsin aggregation as confirmed by thioflavin T (ThT) and Congo Red (CR) binding assays, complemented by circular dichroism (CD) and fluorescence microscopic results. Computational tools (PASTA, WALTZ-DB 2.0, AggreProt 1.0, and TANGO) identified five aggregation-prone regions as key targets. The binding affinity of daphnetin was pH-dependent, highest at pH 4.2, and decreasing at pH 2.0, 7.4, and 9.0. Metal ions (Cu2+ and Zn2+) were found to increase daphnetin's binding affinity towards pepsin. The enzyme kinetic analysis revealed that daphnetin inhibited pepsin activity through a competitive inhibition mode. These experimental results were further supported by computational analysis, elucidating the dynamics of daphnetin within pepsin network.

This study focuses on synthesizing an injectable and self-healing hydrogel from an abundant serum protein (bovine serum albumin, BSA) to control antimicrobial drug delivery impeding bacterial infections. Hydrogels were synthesized through a green synthesis route without using any crosslinking agent and characterized for their cross-linking, surface morphology, self-healing, viscoelasticity, injectability, and swelling and degradation properties. The prepared hydrogel has distinctive autofluorescence properties, as observed from the wavelength-dependent steady-state fluorescence spectral measurements. When lomefloxacin and doxycycline were incorporated into the hydrogel network, it allowed the controlled release of both antibiotics over at least 24 hours, with a release rate of over 90%. Hydrogels containing lomefloxacin and doxycycline were effectively used against E. coli and E. faecalis bacterial strains; their antibacterial effects were maintained for 24 hours. The live/dead cell test indicated that the hydrogel is effective against both (Gram-positive and Gram-negative) bacteria strains. Furthermore, our studies on bacteria encapsulation, specifically using E. coli, confirmed that the hydrogel is non-toxic, and the hydrogel demonstrates biocompatibility as the bacteria successfully grow within the hydrogel matrix. To assess biocompatibility, we conducted a cell attachment experiment with HEK 293 cells, and the results suggest that this hydrogel could be used for 3D cell culturing in the future. A greener route for the synthesis of serum albumin-based self-healing, injectable and autofluorescent hydrogels for drug delivery applications and biocompatibility.

In this study, we investigated the complexation of bioactive isoflavones, specifically biochanin A (BCA) and genistein (GEN), with hen egg white lysozyme (HEWL) and explored their inhibitory effects on HEWL modification using a combination of multi-spectroscopic and computational methods. The observed binding affinity was of a moderate nature (on the order of 104 M-1), and a static quenching mechanism was identified in the fluorescence quenching process. Notably, the binding constant (Kb) for GEN (4.449 +/- 0.262 x 104 M-1) was found to be higher than that for BCA (3.707 +/- 0.108 x 104 M-1) towards HEWL. Our spectroscopic measurements, complemented by molecular docking calculations, suggested the involvement of Trp62 in the binding site of the isoflavones within the geometry of HEWL. The micro-environment surrounding the Trp-residues exhibited an increase in hydrophilicity, as indicated by Synchronous fluorescence (SFS) and three-dimensional fluorescence (3D) studies. Interestingly, circular dichroism (CD) studies revealed no marked alteration in the secondary structure of HEWL upon binding with the isoflavones. Furthermore, our investigation into the interaction patterns, employing FTIR and molecular docking studies, revealed a predominance of hydrogen bonding and hydrophobic interactions. Beyond the binding study, the isoflavones demonstrated a promising inhibitory effect on the D-ribose-mediated glycation of HEWL, as well as on HEWL fibrillation, as evidenced by fluorescence emission studies. Our findings not only exhibited an excellent correlation with experimental observations but also provided precise insights into the location and dynamics of isoflavones within the binding site through detailed analyses of molecular docking and molecular dynamics simulation data.

In recent decades, Cd-based quantum dots (QDs) have gained tremendous interest as luminescence tags for numerous biological applications. However, chemical synthesis using organic molecules to encapsulate the QDs surface is a highly complex process, high-cost and aggressive fabrication, and less aqueous and biocompatible, which leads to restricted biological applications. In this paper, we have reported the biogenic synthesis of CdSe-HSA core and CdSe@ZnSe-HSA core-shell QDs for the first time using human serum albumin protein as a surface engineering molecule. The biosynthesized QDs were found to be smaller in size (2-3.5 nm) and highly aqueous compatible (stable for up to 150 days). The biosynthesized QDs act as ultrasensitive fluorescence probes for label-free sensing of Hg2+ with enhanced efficiency, and an LOD value of 1.3 nM for CdSe@ZnSe-HSA QDs (concentration range: 0-2 mu M) was obtained and were also able to detect with the naked eye. A dynamic quenching mechanism was observed for the fluorescence quenching of the biosynthesized QDs by Hg2+ ions, and affinity toward the formation of Hg-Se or Hg-SH with the QDs provided the unique selectivity. Moreover, the smaller size and unique surface properties of the biosynthesized QDs contributed to the enhanced antibacterial properties against Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria and found more effective against Gram-negative bacteria. This work implies the biogenic aqueous compatible synthesis of core and core-shell QDs for biological and environmental monitoring analytical methods for the development of bionanotechnology.

Flavonoids are significant dietary components and have ability to coordinate with metal ions to produce novel drug discovery leads that are superior to those of the parent flavonoids. Here, in this report, we have synthesized chrysin-Cu(II) complex (as per reported article) and characterized it further with different analytical techniques. The synthesized complex was evaluated for radical scavenging and cell cytotoxicity studies where it exhibited enhanced activity as compared to bare chrysin. The interaction studies of the complex with ct-DNA (Kb ⁓ 105 M-1), human serum albumin (HSA) and ovalbumin (Kb ⁓ 104 M-1) were evaluated using multi-spectroscopic and molecular docking studies. Groove binding mode with ct-DNA was observed as confirmed from competitive displacement studies, viscosity measurement, melting temperature estimation and docking analyses. The complex exhibited comparatively higher affinity towards ct-DNA which indicated it efficient transportation by the carrier proteins and controlled release in the target DNA.