Exosomes: A Cutting-Edge Theranostics Tool for Oral Cancer.

Exosomes are a subpopulation of extracellular vesicles (EVs) secreted by cells. In cancer, they are key cellular messengers during cancer development and progression. Tumor-derived exosomes (TEXs) promote cancer progression. In oral cancer, the major complication is oral squamous cell carcinoma (OSCC). Exosomes show strong participation in several OSCC-related activities such as uncontrolled cell growth, immune suppression, angiogenesis, metastasis, and drug and therapeutic resistance. It is also a potential biomarker source for oral cancer. Some therapeutic exosome sources such as stem cells, plants (it is more effective compared to others), and engineered exosomes reduce oral cancer development. This therapeutic approach is effective because of its specificity, biocompatibility, and cell-free therapy (it reduced side effects in cancer treatment). This article highlights exosome-based theranostics signatures in oral cancer, clinical trials, challenges of exosome-based oral cancer research, and future improvements. In the future, exosomes may become an effective and affordable solution for oral cancer.

Formulation of silver nanoparticles using Duabanga grandiflora leaf extract and evaluation of their versatile therapeutic applications.

The current research focused on the green synthesis of silver nanoparticles (AgNPs) using Duabanga grandiflora leaf extract. The green synthesis of AgNPs was confirmed by the surface plasmon resonance band at 453 nm in a UV-Visible analysis. The formulated AgNPs had a diameter of around 99.72 nm with a spherical shape. Fourier transform infrared (FTIR) spectrum revealed the bio-reducing potential of phytochemicals present in D. grandiflora, which fundamentally influenced the synthesis of AgNPs. Zeta potential, dynamic light scattering (DLS), scanning electron microscopic (SEM), energy-dispersive X-ray spectroscopic (EDX), X-ray diffraction (XRD), and transmission electron microscopic (TEM) analyses were executed to reveal the physicochemical attributes of the AgNPs. The AgNPs were further investigated for their antioxidant, antidiabetic, anticancer, and antibacterial potential. The DPPH free radical assay revealed the potential radical scavenging capacity (IC50 = 76.73 µg/ml) of green synthesized AgNPs. α-Amylase inhibitory assay displayed significant inhibitory potential (IC50 = 162.11 µg/ml) of this starch-breaking enzyme by AgNPs, revealing the antidiabetic potential of AgNPs. AgNPs exhibited potential cytotoxic activity (IC50 = 244.57 µg/ml) against malignant human kidney cells. In addition, AgNPs showed outstanding antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial strains. Interestingly, AgNPs showed cytotoxic and antimicrobial activities at much higher concentrations than radical scavenging and α-amylase inhibitory concentrations. Thus, our finding elaborated the scope of green synthesized AgNPs for diverse therapeutic applications (dose-dependent) for further clinical translation.

Role of Exosomes in Epithelial-Mesenchymal Transition.

Epithelial-mesenchymal transition (EMT) is a fundamental process driving cancer metastasis, transforming non-motile cells into a motile population that migrates to distant organs and forms secondary tumors. In recent years, cancer research has revealed a strong connection between exosomes and the EMT. Exosomes, a subpopulation of extracellular vesicles, facilitate cellular communication and dynamically regulate various aspects of cancer metastasis, including immune cell suppression, extracellular matrix remodeling, metastasis initiation, EMT initiation, and organ-specific metastasis. Tumor-derived exosomes (TEXs) and their molecular cargo, comprising proteins, lipids, nucleic acids, and carbohydrates, are essential components that promote EMT in cancer. TEXs miRNAs play a crucial role in reprogramming the tumor microenvironment, while TEX surface integrins contribute to organ-specific metastasis. Exosome-based cancer metastasis research offers a deeper understanding about cancer and an effective theranostic platform development. Additionally, various therapeutic sources of exosomes are paving the way for innovative cancer treatment development. In this Review, we spotlight the role of exosomes in EMT and their theranostic impact, aiming to inspire cancer researchers worldwide to explore this fascinating field in more innovative ways.

Unlocking Exosome-Based Theragnostic Signatures: Deciphering Secrets of Ovarian Cancer Metastasis.

Ovarian cancer (OC) is a common gynecological cancer worldwide. Unfortunately, the lack of early detection methods translates into a substantial cohort of women grappling with the pressing health crisis. The discovery of extracellular vesicles (EVs) (their major subpopulation exosomes, microvesicles, and apoptotic bodies) has provided new insights into the understanding of cancer. Exosomes, a subpopulation of EVs, play a crucial role in cellular communication and reflect the cellular status under both healthy and pathological conditions. Tumor-derived exosomes (TEXs) dynamically influence ovarian cancer progression by regulating uncontrolled cell growth, immune suppression, angiogenesis, metastasis, and the development of drug and therapeutic resistance. In the field of OC diagnostics, TEXs offer potential biomarkers in various body fluids. On the other hand, exosomes have also shown promising abilities to cure ovarian cancer. In this review, we address the interlink between exosomes and ovarian cancer and explore their theragnostic signature. Finally, we highlight future directions of exosome-based ovarian cancer research.

Preparation of silver nanoparticles by Osbeckia stellata aqueous extract via green synthesis approach: Characterization and assessment of their antioxidant, antidiabetic, cytotoxicity, and antibacterial properties.

Silver nanoparticles (Ag NPs) via green synthesis using medicinal plants have been widely used in natural product research due to the economical and eco-friendly properties of NPs. The plant-derived Ag NPs biosynthesis comprises the interaction between silver nitrate (precursor) and bioactive components of plant extract (reducing agents). In this work, Ag NPs were biosynthesized using Osbeckia stellata leaves aqueous extract. Characterization of Ag NPs was done by using ultraviolet-visible absorption (UV-Vis) spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray analysis (EDX). Further, antioxidant, antidiabetic, cytotoxicity, and antimicrobial activities were evaluated to establish the pharmacological properties of Ag NPs. UV-Vis spectroscopy and FTIR showed an absorption peak of Ag NPs due to the surface plasmonic resonance. In contrast, the particle size in the nanometer range was analyzed by XRD and DLS. The size of the particle was confirmed by the SEM, TEM, and EDX in the nanometer range. This study showed the spherical shape and crystalline nature of NPs. Zeta potential was used to determine the stability of Ag NPs. Biosynthesized Ag NPs showed significantly potent antioxidant, antidiabetic, and cytotoxicity activity. Ag NPs also showed effectiveness against gram-positive (Escherichia coli) and gram-negative (Staphylococcus aureus) bacteria in the antimicrobial activity study. The result concluded that these Ag NPs might be used in biomedical and pharmacological fields.

Clinical Impact of Exosomes in Colorectal Cancer Metastasis.

Cancer is a complex deadly disease that has caused a global health crisis in recent epochs. Colorectal cancer (CRC) is the third most common malignant gastrointestinal disease. It has led to high mortality due to early diagnostic failure. Extracellular vesicles (EVs) come with promising solutions for CRC. Exosomes (a subpopulation of EVs) play a vital role as signaling molecules in CRC tumor microenvironment. It is secreted from all active cells. Exosome-based molecular transport (DNA, RNA, proteins, lipids, etc.) transforms the recipient cell's nature. In CRC, tumor cell-derived exosomes (TEXs) regulate multiple events of CRC development and progression such as immunogenic suppression, angiogenesis, epithelial-mesenchymal transitions (EMT), physical changes in the extracellular matrix (ECM), and metastasis. Biofluid-circulated tumor-derived exosomes (TEXs) are a potential tool for CRC liquid biopsy. Exosome-based colorectal cancer detection creates a great impact in CRC biomarker research. The exosome-associated CRC theranostics approach is a state-of-the-art method. In this review, we address the CRC and exosomes complex associated with cancer development and progression, the impact of exosomes on CRC screening (diagnostic and prognostic biomarkers), and also highlight several exosomes with CRC clinical trials, as well as future directions of exosome-based CRC research. Hopefully, it will encourage several researchers to develop a potential exosome-based theranostic tool to fight CRC.

Glucose oxidase-copper hybrid nanoflowers embedded with magnetic nanoparticles as an effective antibacterial agent.

Bacterial contamination causes various problems ranging from bacterial infection to biofouling. As an effective and non-toxic agent for bacterial de-contamination, glucose oxidase (GOx)-copper hybrid nanoflowers embedded with amine-functionalized magnetic nanoparticles (NH2-MNPs), called 'MNP-GOx NFs', are developed. Positively-charged NH2-MNPs and negatively-charged GOx molecules are first interacted via electrostatic attraction which can be controlled by changing the buffer pH, and the follow-up addition of copper(II) sulfate leads to blooming of nanoflowers (MNP-GOx NFs) after incubation at room temperature for 3 days. MNP-GOx NFs show effective antibacterial activity by generating H2O2 from GOx-catalyzed glucose oxidation. For example, 99.9% killings of Staphylococcus aureus and Escherichia coli are achieved after 3 h treatment of 106/mL cells with 0.2 and 3.0 mg/mL MNP-GOx NFs, respectively, revealing that Gram-positive S. aureus with mono-layer membrane system is more vulnerable to the treatment of MNP-GOx NFs than Gram-negative E. coli with two-layer membrane system. MNP-GOx NFs can maintain 97% of bactericidal activity even after recycled uses by magnetic separation for eight times iterative bacterial killings. Finally, MNP-GOx NFs are employed for the fabrication of antibacterial gauzes. MNP-GOx NFs have also opened up a great potential for their applications in biosensors, biofuel cells and bioconversion as well as bacterial de-contamination.

Enzyme-Immobilized Chitosan Nanoparticles as Environmentally Friendly and Highly Effective Antimicrobial Agents.

Highly effective and minimally toxic antimicrobial agents have been prepared by immobilizing glucose oxidase (GOx) onto biocompatible chitosan nanoparticles (CS-NPs). CS-NPs were prepared via ionotropic gelation and used for the immobilization of GOx via approaches of covalent attachment (CA), enzyme coating (EC), enzyme precipitate coating (EPC), and magnetic nanoparticle-incorporated EPC (Mag-EPC). EPC represents an approach consisting of enzyme covalent attachment, precipitation, and cross-linking, with CA and EC being control samples while Mag-EPC was prepared by mixing magnetic nanoparticles (Mag) with enzymes during the preparation of EPC. The GOx activities of CA, EC, EPC, and Mag-EPC were 8.57, 17.7, 219, and 247 units/mg CS-NPs, respectively, representing 26 and 12 times higher activity of EPC than those of CA and EC, respectively. EPC improved the activity and stability of GOx and led to good dispersion of CS-NPs, while Mag-EPC enabled facile magnetic separation. To demonstrate the expandability of the EPC approach to other enzymes, bovine carbonic anhydrase was also employed to prepare EPC and Mag-EPC samples for their characterizations. In the presence of glucose, EPC of GOx generated H2O2 in situ, which effectively inhibited the proliferation of Staphylococcus aureus in both suspended cultures and biofilms, thereby demonstrating the potential of EPC-GOx as environmentally friendly and highly effective antimicrobial materials.

Magnetic Nanoparticles-Embedded Enzyme-Inorganic Hybrid Nanoflowers with Enhanced Peroxidase-Like Activity and Substrate Channeling for Glucose Biosensing.

It is reported that glucose oxidase (GOx)-copper hybrid nanoflowers embedded with Fe3 O4 magnetic nanoparticles (MNPs) exhibit superior peroxidase-mimicking activity as well as substrate channeling for glucose detection. This is due to the synergistic integration of GOx, crystalline copper phosphates and MNPs being in close proximity within the nanoflowers. The preparation of MNP-embedded GOx-copper hybrid nanoflowers (MNPs-GOx NFs) begins with the facile conjugation of amine-functionalized MNPs with GOx molecules via electrostatic attraction, followed by the addition of copper sulfate that leads to full blooming of the hybrid nanoflowers. In the presence of glucose, the catalytic action of GOx entrapped in the nanoflowers generates H2 O2 , which is subsequently used by peroxidase-mimicking MNPs and copper phosphate crystals, located close to GOx molecules, to convert Amplex UltraRed substrate into a highly fluorescent product. Using this strategy, the target glucose is successfully determined with excellent selectivity, stability, and magnetic reusability. This biosensor based on hybrid nanoflowers also exhibits a high degree of precision and reproducibility when applied to real human blood samples. Such novel MNP-embedded enzyme-inorganic hybrid nanoflowers have a great potential to be expanded to any oxidases, which will be highly beneficial for the detection of various other clinically important target molecules.

Magnetic nanoparticles for selective capture and purification of an antimicrobial peptide secreted by food-grade lactic acid bacteria.

Biocompatible iron oxide nanoparticles (IONPs) were utilized for charge-based selective capture of the cationic bacteriocin pediocin secreted by food-grade lactic acid bacteria (LAB), resulting in the generation of a nanocomposite, which could be readily separated from other secreted metabolites. Interestingly, pediocin activity was conserved and a membrane-directed antibacterial activity typically associated with pediocin was manifested in the nanocomposite. Efficient sequestration of pediocin was also achieved through facile magnetic separation of IONP-pediocin composites and following desorption at pH 2.0, the recovered IONPs could be recycled for a subsequent round of pediocin adsorption. The steady state adsorption isotherm of pediocin with IONPs followed a Langmuir isotherm model. Following the reversible adsorption-desorption process with IONPs, 16-fold purification of pediocin could be achieved. The HPLC profile of the desorbed pediocin revealed a similar retention time to pediocin purified by an established cell-adsorption method and the HPLC eluted fraction also displayed the signature membrane-directed pediocin activity. The facile capture of pediocin, magnetic separation and the possibility of salvaging IONPs for reuse, accompanied by high retention of pediocin activity during the purification process, enhance the merit of IONPs as robust and effective purification tools for a potentially therapeutic antimicrobial peptide.

Amphiphile-mediated enhanced antibiotic efficacy and development of a payload nanocarrier for effective killing of pathogenic bacteria.

Synthetic amphiphiles have emerged as potent bactericidal scaffolds owing to their high propensity to interact with bacterial cells and a membrane-directed mode of action, which is likely to overcome resistance development in pathogenic bacteria. In this study, we highlighted a membrane-acting quinolinium-based cationic amphiphile (compound 1) as an adjuvant for antibiotic-mediated eradication of pathogenic bacteria and demonstrated the generation of an amphiphile-loaded nanocarrier for potential antibacterial therapy. Treatment of Gram-negative pathogenic bacteria E. coli MTCC 433 and P. aeruginosa MTCC 2488 with 1 resulted in significant augmentation of the activity of erythromycin and a decrease in the minimum inhibitory concentration of the antibiotic. Interestingly, 1 promoted large-scale eradication of P. aeruginosa MTCC 2488 biofilm and could also enhance the anti-biofilm activity of tobramycin in combination. For potential therapeutic applications, a 1-loaded bovine serum albumin-based nanocarrier was developed, which exhibited sustained release of 1 both in physiological and acidic pH and the released amphiphile displayed antibacterial as well as anti-biofilm activities. Interestingly, the nanocarrier also displayed the signature membrane-directed activity of 1 against tested pathogenic bacteria. The high bactericidal and anti-biofilm activities in conjunction with a lack of cytotoxic effect on HT-29 human cell lines enhance the merit of the amphiphile-loaded nanocarrier as a potentially therapeutic antibacterial against clinically relevant drug-resistant pathogenic bacteria.

NIR- and FRET-based sensing of Cu2+ and S2- in physiological conditions and in live cells.

We have synthesized a new indole functionalized rhodamine derivative L(1) which specifically binds to Cu(2+) in the presence of large excess of other competing ions with visually observable changes in their electronic and fluorescence spectral behavior. These spectral changes are significant enough in the NIR and visible region of the spectrum and thus enable naked eye detection. The receptor, L(1), could be employed as a resonance energy transfer (RET) based sensor for detection of Cu(2+) based on the process involving the donor indole and the acceptor Cu(2+) bound xanthene fragment. Studies reveal that L(1)-Cu complex is selectively and fully reversible in presence of sulfide anions. Further, fluorescence microscopic studies confirmed that the reagent L(1) could also be used as an imaging probe for detection of uptake of these ions in HeLa cells.

Quantitative Appraisal of the Probiotic Attributes and In Vitro Adhesion Potential of Anti-listerial Bacteriocin-producing Lactic Acid Bacteria.

Estimation of bile tolerance, endurance to gastric and intestinal environment and adhesion potential to intestinal cells are significant selection criteria for probiotic lactic acid bacteria (LAB). In this paper, the probiotic potential of native bacteriocin-producing LAB isolated previously from indigenous source has been determined through quantitative approaches. Among fifteen anti-listerial bacteriocin-producing native LAB, ten strains were found to be bile tolerant. The presence of bile salt hydrolase (bsh) gene in native Lactobacillus plantarum strains was detected by PCR and confirmed by nucleic acid sequencing of a representative amplicon. Interestingly, three native LAB strains exhibited significant viability in simulated gastric fluid, analogous to the standard LAB Lactobacillus rhamnosus GG, while an overwhelming majority of the native LAB strains demonstrated the ability to survive and remain viable in simulated intestinal fluid. Quantitative adhesion assays based on conventional plating method and a fluorescence-based method revealed that the LAB isolates obtained from dried fish displayed significant in vitro adhesion potential to human adenocarcinoma HT-29 cells, and the adhesion level was comparable to some of the standard probiotic LAB strains. The present study unravels putative probiotic attributes in certain bacteriocin-producing LAB strains of non-human origin, which on further in vivo characterization could find specific applications in probiotic food formulations targeted for health benefits.

Synthetic amphiphiles as therapeutic antibacterials: lessons on bactericidal efficacy and cytotoxicity and potential application as an adjuvant in antimicrobial chemotherapy.

In this paper, we present a critical assessment of the therapeutic potential of low molecular weight pyridine-based synthetic amphiphiles based on structure-guided bactericidal activity and a rational evaluation of their cytotoxic potential. Fluorescence-based structure-function studies revealed that the amphiphiles were membrane-acting and displayed a hierarchical pattern of bactericidal activity, which could be correlated with their charge density and hydrophobicity. The membrane-targeting activity of the most potent cationic amphiphile (compound 6) was vindicated as it induced extensive membrane-disruption and dissipation of the transmembrane potential (ΔΨ) in pathogenic bacteria. At concentrations equivalent to the minimum inhibitory concentration (MIC) against the Gram-positive pathogen S. aureus MTCC 96, none of the amphiphiles exerted any cytotoxic effect on model human cell lines (HeLa, MCF-7 and HT-29). However, at elevated concentrations, a distinct gradation in the cytotoxic effect was manifested, which is probably accounted by the charge density and conformational flexibility of the amphiphiles. A viable therapeutic application of compound 6 is demonstrated in combinatorial assays, wherein the proclivity of the amphiphile to disrupt bacterial membranes at very low concentration is exploited to enhance the uptake and bactericidal efficacy of erythromycin against Gram-negative pathogenic bacteria.

Membrane-directed high bactericidal activity of (gold nanoparticle)-polythiophene composite for niche applications against pathogenic bacteria.

The use of nanoscale materials as bactericidal agents represents a novel paradigm in the development of therapeutics against drug-resistant pathogenic bacteria. In this paper the antimicrobial activity of a water soluble (gold nanoparticle)-polythiophene (AuNP-PTh) composite against common bacterial pathogens is reported. The nanocomposite is broad-spectrum in its bactericidal activity and exhibits a membrane-directed mode of action on target pathogens. The therapeutic potency of AuNP-PTh is demonstrated by experiments which reveal that the nanocomposite can breach the outer membrane defense barrier of Gram-negative pathogens for subsequent killing by a hydrophobic antibiotic, inhibit the growth of model gastrointestinal pathogens in simulated gastric fluid, and significantly eradicate bacterial biofilms. The high bacterial selectivity and lack of cytotoxicity on human cells augers well for future therapeutic application of the nanocomposite against clinically relevant pathogenic bacteria.

Retention of nisin activity at elevated pH in an organic acid complex and gold nanoparticle composite.

Biocompatible organic acids and citrate-stabilized gold nanoparticles were interacted with nisin to generate robust antimicrobial agents, which display archetypical nisin activity even at elevated pH.

Fluorescence-Based Comparative Evaluation of Bactericidal Potency and Food Application Potential of Anti-listerial Bacteriocin Produced by Lactic Acid Bacteria Isolated from Indigenous Samples.

The aim of the present study was to ascertain the potency of anti-listerial bacteriocin produced by lactic acid bacteria (LAB) isolated from indigenous samples of dahi, dried fish, and salt-fermented cucumber. A total of 231 LAB isolates were obtained from the samples, of which 51 isolates displayed anti-listerial activity. The anti-listerial LAB were identified by PCR as Lactobacillus sp., Pediococcus sp., Enterococcus sp., and Lactococcus sp. PCR also enabled the detection of Class IIa bacteriocin-encoding genes such as enterocin A, pediocin, and plantaricin A in some of the LAB isolates. The culture filtrate from anti-listerial LAB isolates demonstrated bacteriocin-like inhibitory substance (BLIS) against common Gram-positive pathogenic bacteria such as Staphylococcus aureus, Enterococcus faecalis, and Bacillus cereus, and partial characterization of BLIS confirmed the production of bacteriocin by the LAB isolates. Sensitive fluorescence-based assays employing specific probes indicated the comparative potencies of the bacteriocin and clearly revealed the membrane-targeted anti-listerial activity of the purified bacteriocin produced by selected LAB isolates. The food application potential of plantaricin A produced by a native isolate Lactobacillus plantarum CRA52 was evidenced as the bacteriocin suppressed the growth of Listeria monocytogenes Scott A inoculated in paneer samples that were stored at 8 °C for 5 days.

2-Alkylmalonic acid: amphiphilic chelator and a potent inhibitor of metalloenzyme.

The present investigation demonstrates the potential of 2-alkylmalonic acid amphiphile as inhibitor of metalloenzymes like Taq DNA polymerase and alpha-amylase. A dose-dependent inhibition of Taq DNA polymerase was observed when a polymerase chain reaction (PCR) was performed in the presence of amphiphiles while in the case of alpha-amylase the inhibition was found to be independent of the inhibitor concentration. Control experiments revealed that both the chelating as well as the amphiphilic nature of the inhibitor was essential for enzyme inhibition. The fluorescence intensity and lifetime of alpha-amylase were also found to decrease in the presence of the amphiphiles. Steady-state fluorescence quenching studies suggested that removal of the metal ion from the enzyme leads to a decrease in the solvent accessibility of tryptophans, indicating change in the tertiary structure of the protein. It is proposed that removal of metal ion from the active sites of the enzyme by the amphiphilic compound possibly leads to disruption of the native conformation of the enzyme which is responsible for loss of its activity.