ACS Applied Materials & Interfaces

Red-emitting carbon quantum dots (HP-CQDs) were synthesised for the first time from aqueous leaf extracts of Hamelia patens through single-step, reagent-free microwave-assisted carbonisation (750 W). The resulting nanoparticles displayed a narrow hydrodynamic size distribution centred at 3.9 nm, consistent with atomic force microscopy measurements showing a maximum height of 2.81 nm. Under 400 nm excitation, the CQDs exhibited a characteristic red emission maximum at 675 nm, representing a rare example of long-wavelength-emitting green CQDs derived from plant biomass. UV-Vis absorption bands at 224 and 256 nm were assigned to {pi}-{pi}* transitions of aromatic carbon domains and n-{pi}* transitions associated with carbonyl-containing surface groups, respectively. X-ray photoelectron spectroscopy (XPS) indicated a carbon-rich composition (C: 67.24%, O: 31.25%, N: 1.52%) with prominent C-O (42.67%) and C-C/C=C (42.64%) contributions. ATR-FTIR further confirmed the retention of hydroxyl, ether, and aliphatic functionalities following carbonisation. The excitation-wavelength-independent emission peak position implicates discrete surface molecular states rather than a heterogeneous distribution of emitters. HP-CQDs exhibit potent DPPH radical scavenging activity (IC50 = 141.8 {micro}g mL-1), comparable to ascorbic acid (IC50 = 114.8 {micro}g mL-1), and maintain >95% cell viability in both HeLa and RPE-1 cells up to 250 {micro}g mL-1. Confocal microscopy demonstrates concentration-dependent cytoplasmic accumulation and selective perinuclear localization at 300 {micro}g mL-1. In vivo biodistribution in zebrafish larvae confirms systemic uptake with statistically significant fluorescence enhancement at 500 {micro}g mL-1 (p < 0.01), establishing HP-CQDs as biocompatible red-fluorescent probes with dual imaging-antioxidant functionality. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/724069v1_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@1dbe864org.highwire.dtl.DTLVardef@763ed0org.highwire.dtl.DTLVardef@115e9b9org.highwire.dtl.DTLVardef@1a3941e_HPS_FORMAT_FIGEXP M_FIG C_FIG

Carbon quantum dots derived from mango leaves exhibited bright red fluorescence. These negatively charged particles underwent coating with the positively charged lipid molecule N-[1-(2,3-dioleyloxy) propyl]-N,N,N-trimethylammonium chloride (DOTMA). However, the bioconjugate displayed reduced uptake compared to the standalone mQDs in cancer cells (SUM 159A), and increased uptake in the case of epithelial (RPE-1) cells. Upon in vitro testing, the bioconjugate demonstrated a mitigating effect on the individual toxicity of both DOTMA and mQDs in SUM-159A (cancerous cells) and of DOTMA in RPE-1 cells. Conversely, it exhibited a proliferative effect on RPE-1 (epithelial cells). Surface modifications of QDs with lipids thus enhances their compatibility with biological systems, reducing systemic toxicity, minimizing off-site effects, sustaining drug release, and modulating cellular viability through various mechanisms (for example, apoptosis), which is, therefore, crucial for multiple applications such as targeted therapeutics. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/587464v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1eca201org.highwire.dtl.DTLVardef@7ff0a3org.highwire.dtl.DTLVardef@18f89b2org.highwire.dtl.DTLVardef@993b42_HPS_FORMAT_FIGEXP M_FIG C_FIG Red emitting, fluorescent carbon quantum dots synthesized using mango leaves(mQDs) showed enhanced cellular uptake and reduced cell viability in the case of cancer cells when compared with lipid-coated mQDs. However, in the case of non-cancerous cells, the lipid-coated mQDs showed enhanced cellular uptake and cell viability when compared with mQDs alone.

Surface functionalization of biomaterials enables the immobilization of proteins and other molecules and can be utilized to direct the biological response to devices and implants. Fetuin-A is a blood plasma protein involved in numerous physiological processes, including the regulation of mineralization. Notably, many investigations of fetuin-A have explored its cellular interaction when in solution, but limited studies report the role of fetuin-A when used as a surface modifier. The present investigation explores the response elicited by fetuin-A on Saos-2 cells when it is immobilized on a model gold surface through the covalent reaction with dithiobis(succinimdyl propionate) (DSP). Comparative surface characterization using x-ray photoelectron spectroscopy (XPS), atomic force microscopy - infrared spectroscopy (AFM-IR) and surface plasmon resonance (SPR) confirmed the surface modifications but indicate partial inhomogeneity in the functionalizer surface coverage. The interaction of albumin and fetuin-A with the surface was quantified by radiolabeling, quartz crystal microbalance with dissipation (QCM-D) and SPR, demonstrating a higher mass of fetuin-A bound to the surface in comparison to serum albumin. Over 7 days, cells bound to the surfaces with immobilized fetuin-A showed significantly hindered proliferation of osteoblast-like cells compared to the positive control (fibronectin), presumably due to a decrease in cell metabolism. This study provides new insights into the role of fetuin-A in regulating Saos2 cell response and elucidates its potential use in combination with chemical functionalizers for biomedical applications requiring surface modification.

Although electrostatic modification of bacterial surfaces using polyelectrolytes (PEs) is a convenient and versatile tool for biotechnological processes, the ambiguities in toxicity of PEs between various bacteria and the insufficient understanding of the mechanism of action of cationic PEs and their nano-thick shells formed around the bacteria create a bottleneck of the approach. Here, we show how the viability of two bacterial strains, Escherichia coli and Pseudomonas stutzeri, both from the Gram-negative group differs, when the cells are exposed to cationic PEs under different conditions. Although the cell wall architecture of the strains should be structurally similar, we found that the viability of E. coli was not affected by the electrostatic deposition of polyethyleneimine (PEI) or poly(allylamine) hydrochloride (PAH), whereas for P. stutzeri the deposition resulted in high death rates. The cells of E. coli proved to be suitable templates for Layer-by-Layer (LbL) modification, while in P. stutzeri a modified protocol with mild conditions had to be used to ensure the viability of the cells. Super resolution stimulated emission depletion (STED) microscopy allowed us to clearly visualize that after PE deposition onto the surface of the cells, the PEs could penetrate inside the cells of P. stutzeri, while forming a capsule around E. coli as expected. Therefore, this knowledge will help us select the most appropriate combinations of strains and PEs, for biotechnological processes or biomedical application, preventing unwanted toxicity.

Towards the goal of developing bio-chip / lab-on-a-chip substrates capable of performing highly specific bio-chemical reactions, Neutravidin binding to mixed Biotinylated Silane Self-Assembled Monolayers were studied using Confocal Fluorescence Light Microscopy. Non-specific bindings, specifically the formations of Neutravidin clusters, were quantified. Several experiments were conducted to determine the concentrations of Neutravidin necessary to not saturate surface binding to Biotinylated Self-Assembled Monolayers, determine the effectiveness of using FBS blocking buffers to reduce non-specific binding, optimize the repeatability of Neutravidin binding to Biotinlyated mixed Self-Assembled Monolayers with Silane-PEG-Biotin compositions ranging from 0 to 15%, and quantify background Neutravidin bindings and the corresponding formations of Neutravidin clusters to Self-Assembled Monolayers as Silane-PEG-Biotin percent compositions increase from 0 to 15%. The Neutravidin, Silane-PEG-Biotin, and Silane mPEG concentrations and ratios needed to develop homogeneous Neutravidin films, without the formations of clusters, on the Self-Assembled Monolayers have been determined.

One of the crucial requirements of quantum dots for biological applications is their surface modifications for very specific and enhanced biological recognition and uptake. Toward this, we present the green synthesis of bright, red-emitting carbon quantum dots derived from mango leaf extract (mQDs). These mQDs are conjugated electrostatically with dopamine to form mQDs-dopamine (mQDs: DOPA) bioconjugates. Bright red fluorescence of mQDs was used for bioimaging and uptake in multiple cell lines, tissues, and in vivo models like zebrafish. mQDs exhibited the highest uptake in brain tissue as compared to others. mQD:DOPA conjugate induced cellular toxicity only in cancer cells while showing increased uptake in epithelial cells and zebrafish. Additionally, the mQDs: DOPA promoted neuronal differentiation of SH-SY5Y cells to complete neurons. Both mQDs and mQDs: DOPA exhibited potential for higher collective cell migrations implicating their future potential as next-generation tools for advanced biological and biomedical applications. TOCmQDs were electrostatically conjugated with dopamine (DOPA) to form the mQDs: DOPA bioconjugate. mQDs are used to image cells, tissues, and zebrafish embryos. mQDs: DOPA kills cancer cells, differentiates neuronal cells, and increases the uptake of mQDs in zebrafish embryos. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/545347v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@f521a4org.highwire.dtl.DTLVardef@173a8f0org.highwire.dtl.DTLVardef@585271org.highwire.dtl.DTLVardef@8c959d_HPS_FORMAT_FIGEXP M_FIG C_FIG

This study had a two-fold objective: To utilize collagen hydrolysate for synthesizing a nanoscale Hydroxyapatite (HA) coating that would act as a superior osteoblast adhesion/proliferation agent compared to collagen-derived HA (C/HA) and to comprehend the significant role played by structural constraints on HA nucleation. Collagen was extracted from pacu skin with a high yield of 65.3% (w/w of tissue). It was digested by collagenase and the hydrolysate (CH) was purified with a high yield of 0.68g/g of collagen. The CH peptides had a mass of 6kDa, a predominant PP-II conformation and formed self-assembling hierarchical structures at physiological pH with dimensions of 842.2{+/-}229nm. The HA synthesized on CH (CH/HA) displayed higher yield when compared to C/HA. Structural analysis of CH/HA revealed that the PP-II peptides coiled to form mimic-helical moieties with reduced intermolecular packing distance of 0.9nm. The mimic helices cross-linked to form a vast quasi-fibrillar network that was comparatively smaller than collagen fibrils but exhibited enhanced stability and greater dynamicity. CH/HA displayed intense calcium-carboxyl interactions, sharper diffraction planes, smaller size of 48{+/-}6.2nm and a Ca/P ratio closer to 1.69 when compared to C/HA along with displaying serrated edge blooming crystals. Because of the small size, the CH/HA nanocrystals displayed significantly better osteoblast adhesion than C/HA and reduced the doubling time of cells. Overall, the results indicated that CH based nanocomposites displayed suitable morphological characteristics and cellular response for potential application as implant and bone graft coating material. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/431097v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@1b020c2org.highwire.dtl.DTLVardef@36a899org.highwire.dtl.DTLVardef@77106aorg.highwire.dtl.DTLVardef@d6b801_HPS_FORMAT_FIGEXP M_FIG C_FIG

The rapid emergence of drug-resistant bacteria and fungi poses a threat for healthcare worldwide. The development of novel effective small molecule therapeutic strategies in this space has remained challenging. An orthogonal approach, therefore, is to explore biomaterials with physical modes of action which have the potential to generate antimicrobial activity and in some cases even prevent antimicrobial resistance. Here, to this effect, we describe an approach for forming silk-based films that contain embedded selenium nanoparticles. We show that these materials exhibit both antibacterial and antifungal properties while crucially also remaining highly biocompatible and non-cytotoxic towards mammalian cells. By incorporating the nanoparticles into silk films, the protein scaffold acts in a two-fold manner; it protects the mammalian cells from the cytotoxic effects of the bare nanoparticles, while also providing a template for bacterial and fungal eradication. A range of hybrid inorganic/organic films were produced and an optimum concentration was found, which allowed for both high bacterial and fungal death while also exhibiting low mammalian cell cytotoxicity. Such films can thus pave the way for next generation antimicrobial materials for applications such as wound healing and as agents against topical infections, with the added benefit that bacteria and fungi are unlikely to develop antimicrobial resistance to these hybrid materials.

We successfully harnessed the potential of Artemisia pallens extracts for the eco-friendly biosynthesis of silver, gold, and silver-gold bimetallic nanoparticles, employing aqueous silver nitrate and chloroauric acid solutions. This innovative approach departs from traditional methods, often involving toxic chemical agents like hydrazine hydrate and sodium borohydride. In the quest for greener protocols, the biological route emerges as a non-toxic, straight-forward, and environmentally sound alternative, opening new avenues for translational research. This article discusses the production of silver, gold, and silver-gold nanoparticles using different species of Artemisia plants. Nanoparticle characterization was carried out using UV-visible spectrophotometry, TEM, XRD, and FTIR techniques. Microwave-assisted synthesis resulted in well-dispersed nanoparticles. In the case of silver nanoparticles, a spherical shape with a size of 6 nm was achieved using the microwave radiation-assisted method, while a size of 20 nm was obtained with UV-assisted synthesis. Gold nanoparticles exhibited diverse shapes, including spherical, triangular, prisms, trapezoids, and hexagonal, with a predominant size of 10 nm. The size range for gold nanoparticles varied from 10 nm to 400 nm.

Sustainable synthesis of photoluminescent nanomaterials with tuneable surface chemistry and defined biological activity remains a central challenge in green nanoscience. Here we show that the energy-input route used to carbonise a single bearberry (Arctostaphylos uva-ursi) extract precursor system exerts a decisive and mechanistically coherent influence over the surface chemistry, optical performance, and bioactivity of the resulting carbon quantum dots (CQDs). Hydrothermal processing (160 {degrees}C, 6 h) yields particles of 7.13 nm hydrodynamic diameter enriched in surface hydroxyl and carbonyl groups, a higher graphitic sp{superscript 2} carbon fraction (43.06%), and potent DPPH radical scavenging activity. In contrast, microwave-assisted synthesis yields 9.65 nm particles with a higher surface carboxylate content (O-C=O: 19.06%), enhanced fluorescence quantum yield, and increased intracellular uptake. Uptake is statistically significant in retinal epithelial cells at 200 {micro}g/mL (p < 0.001) and shows concentration-dependent accumulation in zebrafish larvae from 100 {micro}g/mL (p < 0.05). Combined XPS C 1s deconvolution and FTIR difference spectroscopy indicate that incomplete decarboxylation under microwave conditions underlies these distinct properties. Both formulations maintained full cytocompatibility across 10-250 {micro}g/mL in both RPE-1 and HeLa cells, with no statistically significant reduction in viability at any tested concentration. These findings define a synthesis-route-encoded structure property relationship that enables rational selection between antioxidant-optimised and imaging-optimised CQD formulations from an identical green precursor system.

We report the controlled release of an antimicrobial peptide using enzyme-activatable prodrugs to treat and detect Candida albicans and Porphyromonas gingivalis. Our motivation lies in the prevalence of these microorganisms in the subgingival area where the frequency of fungal colonization increases with periodontal disease. This work is based on an antimicrobial peptide that is both therapeutic and induces a color change in a nanoparticle reporter. This antimicrobial peptide was then built into a zwitterionic prodrug that quenches its activity until activation by a protease inherent to these pathogens of interest: SAP9 or RgpB for C. albicans and P. gingivalis, respectively. We first confirmed that the intact zwitterionic prodrug has negligible toxicity to fungal, bacterial, and mammalian cells absent a protease trigger. Next, the therapeutic impact was assessed via disk diffusion and viability assays and showed a minimum inhibitory concentration of 3.1 - 16 {micro}g/mL, which is comparable to the antimicrobial peptide alone (absent integration into prodrug). Finally, the zwitterionic design was exploited for colorimetric detection of C. albicans and P. gingivalis proteases. When the prodrugs were cleaved, the plasmonic nanoparticles aggregated causing a color change with a limit of detection of 10 nM with gold nanoparticles and 3 nM with silver nanoparticles. This approach has value as a convenient and selective protease sensing and protease-induced treatment mechanism based on bioinspired antimicrobial peptides. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/568833v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1e9cf5corg.highwire.dtl.DTLVardef@12cb36forg.highwire.dtl.DTLVardef@1b862f7org.highwire.dtl.DTLVardef@697946_HPS_FORMAT_FIGEXP M_FIG C_FIG

Cancer cell membrane coated biomimetic nanoparticles have been shown to be highly efficient in cellular uptake, homotypic tumour targeting, and the ability to suppress tumour growth compared to uncoated nanoparticles. Long duration anti-cancer treatment regimens require highly stable cancer cell membrane coated biomimetic nanoparticle. To manufacture such highly stable cancer cell membrane coated biomimetic nanoparticle, we used "Click-chemistry" to encapsulate cancer cell membrane on nanoparticles. In situ characterization was done to confirm the functionality of the novel Click-chemistry based formulation to encapsulate cancer cell membrane on nanoparticles. Gold nanoparticles were encapsulated with the cell membranes of cell lines of lung adenocarcinoma, malignant melanoma, high-grade serous epithelial ovarian cancer, colorectal cancer, oral cancer, esophageal adenocarcinoma, adenoid cystic carcinoma of salivary gland, and breast cancer. Functional group analysis, size, morphology, and surface charge confirmed long-stability of the biomimetic nanoparticles after incubating in complete growth medium for 12-months.

Photo-crosslinkable hydrogels are widely employed in biofabrication and tissue engineering as they provide spatiotemporal control over gelation. Most conventional photo-curing hydrogel systems rely upon small-molecule photoinitiators which, upon activation by (ultra)violet irradiation, generate free radicals to initiate polymerization. Such an approach can induce oxidative stress and DNA damage, significantly limiting their use in sensitive biological applications. Here, we present a photoinitiator-free, gelatin-based hydrogel system functionalized with acrylamidylpyrene groups (Gel-Pyr), which undergoes photocrosslinking via a visible-light-induced [2+2] cycloaddition reaction. Gel-Pyr exhibits rapid gelation kinetics, tuneable mechanical properties, facile temporal control over photocrosslinking, and long-term structural stability (>30 days) in cell culture conditions. Rheological analyses reveal pronounced shear-thinning behaviour at room temperature, enabling extrusion-based 3D bioprinting of multilayered constructs with high structural fidelity. Fine strand resolution (<400 {micro}m) is achieved in bioprinted crosshatch structures, enabling sufficient nutrient diffusion for cell support. Encapsulation of human mesenchymal stem cells (hMSCs) within both bulk and printed constructs maintains >80% viability over 7 days, demonstrating robust cytocompatibility. By eliminating UV exposure and free radicals, this visible-light-responsive hydrogel platform offers a facile and cytoprotective alternative to other hydrogel systems. Table of ContentA visible light-crosslinkable, initiator-free gelatin-based hydrogel (Gel-Pyr) is developed using acrylamidylpyrene functionalization. This radical-free system enables rapid crosslinking under cytocompatible reaction conditions and offers excellent printability, tuneable mechanics, and long-term stability. Gel-Pyr supports high cell viability and precision bioprinting, positioning it as a promising platform for tissue engineering and in vitro biofabrication. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/691472v1_ufig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@168fbd5org.highwire.dtl.DTLVardef@16d7e7forg.highwire.dtl.DTLVardef@18beea3org.highwire.dtl.DTLVardef@1e02cd9_HPS_FORMAT_FIGEXP M_FIG C_FIG

"Green nanotechnologies have emerged as environmentally friendly alternatives against microbial multidrug-resistant biofilms. In this study, bactericidal "green" nanolayers (NL) were developed on Ti surfaces using two isomeric phytocompounds, carvacrol (Carv-Ti-NL) and thymol (TOH-Ti-NL). These NLs were fabricated using a one-step immersion treatment method based on a simple and spontaneous self-assembly process. Both NLs revealed strong antimicrobial activity, displaying anti-biofilm and biocidal effects. Notably, TOH-Ti-NL exhibited superior osteogenic performance compared to Carv-Ti-NL, as evidenced by enhanced pre-osteoblast cell attachment and growth, and the production of ALP, collagen type I and Ca2+ deposition. In contrast, fibroblastic cells exhibited reduced attachment on TOH-Ti-NL and enhanced proliferation on Carv-Ti-NL. Considering the biological differential effects, the physicochemical properties of these conformational isomers NLs were studied to elucidate potential differences that could impact on cell response. Although the ATR-FTIR spectra of the NLs were similar and indicated the spontaneous oxidation of Carv and TOH leading to ketonic structures, distinct contributions were observed after the electrooxidation of each NL. Slight differences in hydrophilicity were found for both nanostructures, but higher roughness was found for TOH-Ti-NL. Furthermore, the release curves of Carv and TOH from the NLs revealed distinct profiles over time. Overall, Carv and TOH formed self-assembled layers on Ti able to eradicate Staphylococcus aureus biofilms. Their different physical and chemical characteristics induced distinct responses from eukaryotic cells attached to the NLs. Given these characteristics one might envisage the use of either Carv-Ti-NL or TOH-Ti-NL in order to fine-tune specific chemical physical properties of Ti-based implants. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/610464v1_ufig1.gif" ALT="Figure 1"> View larger version (66K): org.highwire.dtl.DTLVardef@1c288f5org.highwire.dtl.DTLVardef@adc72corg.highwire.dtl.DTLVardef@ef2763org.highwire.dtl.DTLVardef@102d823_HPS_FORMAT_FIGEXP M_FIG C_FIG

Red-emitting carbon nanoparticles (CNPs) were synthesized by the refluxed green synthesis method using ethanolic extract of neem leaves (Azadirachta indica). These nanoparticles were called as nQDs (neem quantum dots). The nQDs exhibited excellent photoluminescence properties with a maximum emission at 672nm, and the average size of nQDs was around 47nm. In the in-vitro study, Retinal Pigment epithelial (RPE1) cells and SUM159A cells showed enhanced cellular uptake. In RPE1 cells, the cellular uptake was higher than in SUM159A cells. In the biocompatibility assay, SUM159A cell viability declined with the increasing nQDs concentration. The results show that red-emissive CNPs can be synthesized from Azadirachta indica (neem) leaves using a simple method with a possible application in bioimaging and therapeutics. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/582094v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@30da5aorg.highwire.dtl.DTLVardef@14f6fbcorg.highwire.dtl.DTLVardef@30e0f0org.highwire.dtl.DTLVardef@ffc962_HPS_FORMAT_FIGEXP M_FIG C_FIG

This study investigates the synthesis of pH-responsive, reversible nanocomposites comprising polystyrene sulfonate (PSS)-coated gold nanorods and poly(allylamine hydrochloride) (PAH)-coated gold nanorods, along with their optical properties. We observed a pH-dependent swelling/shrinking of the nanocomposites and a dramatic red-shift ([~] 60 nm) of the surface plasmon resonance (SPR) peaks as the pH changed from around 5.4 to 7.2 due to the increased side-by-side interactions of adjacent gold nanorods. These pH-responsive nanocomposites, with tunable SPR peaks, hold potential for use as contrast agents in optical molecular imaging. GRAPHICAL ABSTRACTpH-Sensitive Polymer-Coated Gold Nanorods for Reversible SPR Shifts and Applications in pH Sensing as Optical Materials. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC="FIGDIR/small/646487v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@1bb05bforg.highwire.dtl.DTLVardef@1767c02org.highwire.dtl.DTLVardef@1c77356org.highwire.dtl.DTLVardef@1654647_HPS_FORMAT_FIGEXP M_FIG C_FIG

The biosynthesis of silver nanoparticles has recently emerged as a promising approach in nanomedicine, particularly for targeted therapeutic applications. Green synthesized (plant-based) nanoparticles have been shown to offer enhanced reduction efficiency, greater bioavailability, and improved stability compared to synthetic nanoparticles. Here, we report the green synthesis of silver nanoparticles (AgNPs) using Magnolia alba leaf extract. The formation of these Magnolia-derived silver nanoparticles (MAgNPs) was verified through UV-Vis spectroscopy and further characterized by scanning electron microscopy (SEM) which showed that the MAgNPs have a mean diameter of 40 nm and a spherical morphology. The antibacterial efficacy of MAgNPs, evaluated by the well diffusion method, showed significant activity against E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis, and strains of methicillin-resistant and -sensitive Staphylococcus aureus. Disc diffusion and plaque assays demonstrated notable antifungal activity against Candida albicans and antiviral activity against bacteriophage T7. In vitro studies with HCT-116 human colon cancer cells, MAgNPs exhibited significant bi-phasic inhibition of cancer cell growth. These effects were greater than that of the magnolia leaf extracts alone, confirming the green synthesized nanoparticles bioactive efficacy. These findings suggest that MAgNPs possess significant antimicrobial and anticancer activities, indicating their potential as therapeutic agents for certain infections and cancers. Antioxidant assays indicated that MAgNPs exhibit greater antioxidant activity than magnolia leaf extract alone. Results suggest that MAgNPs may have promise as antioxidants for treating free radical-induced disorders. Additionally, MAgNPs showed efficient photocatalytic degradation of the azo bond in methyl orange within 30 minutes, suggesting they may provide a sustainable approach to certain types of environmental pollution. To our knowledge, this is the first report of the biosynthesis of silver nanoparticles using Magnolia alba and examination of their antioxidant and photocatalytic properties, their killing and inhibitory effects on various bacteria, fungi, bacteriophages, and colon cancer.

We present a new class of nitrogen-doped yellow fluorescent carbon dots, synthesized using a one-step hydrothermal method. These bright fluorescent nanoparticles have excitation and emission spectra near the red region of the visible light spectrum that are quite useful for bioimaging applications. Using organic molecules like ortho- phenylenediamine (OPDA), L-ascorbic acid and urea, yellow fluorescent carbon dots (CDs) were synthesized. We obtained a scalable number of CDs having an average size of 3 nm. The CDs show significant emission spectra in the yellow fluorescence region ({lambda}em= 557 nm). The CDs show remarkable stability in their fluorescence in different pH conditions, ionic stability, photostability as well as thermal stability. These CDs are efficiently uptaken by mammalian cells through clathrin-mediated pathway. Apart from in vitro studies we have also used zebrafish larvae as a 3D in vivo model, and showed that CDs were uptaken efficiently by larvae showing maximum accumulation and fluorescence in the yolk sac region and the notochord region. The CDs also offer enhancement in cell proliferation, hence showing the application in wound healing. The fluorescence of CDs is quite robust and is not affected by most external stimuli, hence can be explored as a promising bioimaging tool for targeted bioimaging and biomedical applications.

As the world recovers from the lockdown imposed by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic, returning to shared indoor spaces is considered a formidable risk. It is now clear that transmission of SARS-CoV-2 is driven by respiratory microdroplets expelled by infected persons, which can become suspended in the air. Several layering technologies are being explored to mitigate indoor transmission in the hopes of re-opening business, schools and transportation systems. Here we coupled the water adsorptive and photocatalytic capacity of novel Metal Organic Frameworks (MOFs) to demonstrate the capture and inactivation of SARS-CoV-2. Discussion is given on the methods of analysis and the differences between the photocatalytic activity of several MOFs, and the difference between MOF induced photocatalysis and ultra violet photolysis of SARS-CoV-2. Our results are intended to provide support to industry looking for alternative methods secure indoor spaces.

1Self-assembled monolayers (SAMs) have been widely utilized as a way of tailoring surface chemistry through the adsorption of organic molecules to different materials. SAMs are easy to prepare and offer a wide variety of organic molecules that afford additional or improved properties to the coated material. Spatial control of SAM placement has been achieved over many length-scales, even at the nanoscale. However, nanopatterned SAMs are usually prepared through serial processes utilizing atomic scanning probes or soft-lithography utilizing elastomeric masters. These techniques are expensive or not repeatable. Here we present the use of nanospheres for the creation of nanopatterned Au:Cu films which spatially control the grafting of a thermoresponsive SAM made from poly(N-isopropyl acrylamide) (PNIPAM). Chemical characterization validates the presence of PNIPAM and environmental atomic force microscopy showed its response to temperature which was evidenced by a change in stiffness. Our approach represents an affordable large area methodology for repeatable spatial control of SAMs at the nanoscale.