Search Results (442)

The reusability of enzymes is a fundamental aspect of sustainable biotechnology and the development of biosensors. This study presents one of the first quantitative evaluations of DNA polymerase reusability by utilizing integrated quartz crystal microbalance (QCM) kinetics and real-time monitoring of exonuclease activity. The results showed that immobilized T7 DNA polymerase retained approximately 50% of its initial activity after three 90-min cycles and around 20% after five cycles. Significantly lower activities were observed for shorter, 45-min cycles. This indicates an unexpected time-dependent enhancement in stability for longer reaction times. The findings suggest a promising trend in enzyme stability and reusability, establishing a quantitative relationship between reaction duration and enzyme performance. This relationship offers a scalable pathway for the regeneration of biosensors and for sustainable enzymatic catalysis. Additionally, the work provides a transferable framework that can be applied to other DNA-processing enzymes, which supports long-term biosensor performance and industrial biocatalysis. The demonstrated approach offers a transferable and scalable methodology for the development of reusable polymerase-based biosensors and sustainable biocatalytic systems. Full article

Background: Cisplatin resistance is a major obstacle in the treatment of Hepatocellular carcinoma (HCC), characterized by reduced intracellular drug accumulation and altered DNA repair/apoptosis signaling. Methods: To address this challenge, we developed an acid-responsive nanoplatform consisting of a cisplatin-loaded CaCO₃ core with a lipid coating that enables surface adsorption of Bmi1 siRNA, termed LCa/C@B. Results: These nanoparticles are subsequently coated with positively charged phospholipids, facilitating the absorption of Bmi1 siRNA. In vitro, LCa/C@B markedly enhanced intracellular cisplatin accumulation, downregulated Bmi1 and cancer stem cell (CSC) markers, and restored chemosensitivity in HepG2/MDR cells. In vivo, LCa/C@B achieved improved tumor localization, significant Bmi1 knockdown, suppression of CSC populations, and robust inhibition of tumor growth in a primary HCC model. Importantly, the dual-targeting design produced a synergistic therapeutic effect superior to free cisplatin or single-component formulations. Conclusions: This hybrid drug delivery system, combining calcium carbonate and cisplatin with Bmi1 siRNA, presents a promising approach for overcoming chemotherapy resistance in HCC. Full article

Azobenzene-based hologram recording materials are well known for their rewritable and polarization-selective properties that enable polarization-multiplexed recording and high-density optical storage. High diffraction efficiency, longer retention time, and shorter response time are desirable for rewritable recording materials, but they always require a trade-off relationship. In this study, we show that by simply coating the Azobenzene-based film with multiple layers of a suitable material, these parameters can be improved simultaneously without compromise. Bilayer films and triple layer films were prepared by depositing a DNA–surfactant complex-based layer above and below the azobenzene-based poly(CACzE-MMA) copolymer layer. The hologram recording performance was evaluated in terms of the diffraction efficiency, photoresponse time, and retention behavior of the recorded gratings. Compared with monolayer copolymer films, the multilayer DNA–surfactant complex-based copolymer films exhibited enhanced diffraction efficiency and faster photoresponse. In particular, the bilayer and trilayer structures showed a marked improvement in retention time, indicating suppressed relaxation of refractive index modulation. This enhancement is attributed to molecular confinement at the DNA–surfactant complex and copolymer interfaces generated by the layered architecture. These results demonstrate that a DNA–surfactant complex-based layering approach is an effective strategy for improving hologram stability and highlight the potential of DNA–surfactant complex-derived matrices as effective alternatives to poly(methyl methacrylate) (PMMA) in holographic applications. Full article

The leading cause of post-surgical hospital readmission is the emergence of hospital-acquired infections (HAIs), where surgical site infections (SSIs) constitute a substantial negative impact on patient outcome and contribute annual direct costs estimated to range from $28.4 billion to $45 billion in the U.S. To address the need for novel antimicrobial coating strategies, previous research has demonstrated that certain microbes can degrade poly(aspartic acid) (PAA)-based coatings, suggesting potential limitations of single-compound approaches that must be considered when designing antimicrobial surfaces. In this proof-of-concept study, we investigated whether ordered sequential coatings combining thermally synthesized PAA (tPAA) and oleic acid (OleA) might produce enhanced antimicrobial effects compared to individual compounds. Despite concerns regarding PAA biodegradability, the benefits of using PAA include low cytotoxicity and an ability to chelate metals such as calcium and facilitate bone mineralization and growth post-surgery. Using simple yet effective methods of surface coating applications which utilize tPAA and OleA, we investigated the potential of these ordered coatings to attenuate planktonic and sessile (biofilm) growth and development in Pseudomonas aeruginosa and Escherichia coli in vitro. Application of these ordered coatings resulted in up to 62% reduction in bacterial carrying capacity for P. aeruginosa and up to 43% reduction in biofilm mass relative to untreated controls. Further, confocal imaging via immunohistochemical labeling revealed methods for evaluating the impact of treatments targeting biofilm development through extracellular DNA quantification. Additionally, these coatings show dose-dependent cytotoxic effects against 3T3 mouse fibroblast cells. These preliminary findings, along with results derived from cytotoxicity assessment and physicochemical characterization via dynamic light scattering, suggest that ordered tPAA-OleA coating systems warrant further investigation as potential antimicrobial strategies, though additional validation, including testing against diverse clinical isolates, mechanistic studies, and in vivo evaluation, would be required before clinical application. Full article

We demonstrate that gold nanoparticles (AuNPs) are capable of unwinding double-stranded (ds) DNA. Upon unwinding, the exposed nucleobases of the separated strands adsorb onto the nanoparticle surface, resulting in the coating of the particles. The unwinding process was characterized by Atomic Force Microscopy (AFM) and absorption spectroscopy. Our results show that AuNPs initially bind to single-stranded overhangs at the duplex termini, forming dsDNA–nanoparticle dumbbells. This binding event subsequently initiates the separation of the DNA strands. As the unwinding proceeds, the nanoparticles become progressively wrapped by the unwound DNA strands, which leads to a gradual reduction in the interparticle distance within the dumbbells. This process is driven by the strong affinity of nucleobases for the gold surface. The efficiency of DNA unwinding was found to depend strongly on both nanoparticle size and temperature. These findings provide new insights into DNA-nanoparticle interactions and may facilitate the rational design of DNA–AuNP hybrid nanostructures such as dumbbell-shaped conjugates for applications in DNA-based nanoelectronics, biosensing, and self-assembled nanomaterials. Full article

Rare-earth oxide (REO) nanoparticles (NPs)—such as cerium (CeO₂), samarium (Sm₂O₃), neodymium (Nd₂O₃), terbium (Tb₄O₇), and praseodymium (Pr₂O₃)—have demonstrated strong antimicrobial activity against multidrug-resistant bacteria. Their effectiveness is attributed to unique physicochemical properties, including oxygen vacancies and redox cycling, which facilitate the generation of reactive oxygen species (ROS) that damage microbial membranes and biomolecules. Additionally, electrostatic interactions with microbial surfaces and sustained ion release contribute to membrane disruption and long-term antimicrobial effects. REOs also inhibit bacterial enzymes, DNA, and protein synthesis, providing broad-spectrum activity against Gram-positive, Gram-negative, and fungal pathogens. However, dose-dependent cytotoxicity to mammalian cells—primarily due to excessive ROS generation—and nanoparticle aggregation in biological media remain challenges. Surface functionalization with polymers, peptides, or metal dopants (e.g., Ag, Zn, and Cu) can mitigate cytotoxicity and enhance selectivity. Scalable and sustainable synthesis remains a challenge due to high synthesis costs and scalability issues in industrial production. Green and biogenic routes using plant or microbial extracts can produce REOs at lower cost and with improved safety. Advanced continuous flow and microwave-assisted synthesis offer improved particle uniformity and production yields. Biomedical applications include antimicrobial coatings, wound dressings, and hybrid nanozyme systems for oxidative disinfection. However, comprehensive and intensive toxicological evaluations, along with regulatory frameworks, are required before clinical deployment. Full article

The characterization of cancer and other diseases can be aided by the development of reusable electrochemical sensors that provide broad biomarker expression information in real time. We describe an interdigitated electrode (IDE) sensor array that can be used for rapid detection of multiple biomarkers, including human midkine (MDK), HIV gp41 peptide, mAb 7B2, and single-stranded DNA (ssDNA), using electrochemical impedance spectroscopy (EIS) with coated nanoparticles (NPs). These targets represent potential biomarkers for identifying malignant cancer, HIV infection, and DNA mutation. Targets were detected by coating NPs with an antibody, a protein, and ssDNA to capture them from solution. Interacting proteins attached to the nanoparticles were then analyzed with EIS to identify interaction on the surface. In many biological contexts, more than one partner can interact with selected targets, so the determination of the identity of the interacting component is critical for interpretation. In a controlled system, we verify impedance data clusters based on the identity of the protein coated on the surface of the NPs. Data clusters corresponding to protein identity were clearly bifurcated using the impedance spectrum and unsupervised principal component analysis (PCA). NPs clustered based on surface modification, suggesting individual proteins have unique EIS spectral characteristics that can be used for identification. Full article

Capillary electrophoresis (CE) is an effective tool for the analysis of many biocomponents, such as dsDNA, RNA, amino acids and bacteria, which are extremely important not only in research work but also in numerous practical applications. However, there are many factors that affect the separation performance, including the polymers inside the capillary, the electric field strength, the capillary coating and the effective length of the capillary. So far, various CE techniques have been developed to increase the resolution, sample volume consumption and limit of detection. To better understand the development of techniques for the separation of these biomolecules by CE, this review provides a comprehensive summary of polymers (e.g., polyvinylpyrrolidone, hydroxyethyl cellulose and polyethylene glycol), optimization methods, capillary coating methods, technological advancement of microchips for CE and the limitation of detection proposed by different groups worldwide. We also discuss the challenges and future directions associated with CE technology. Full article

The results of an experimental comparative study on absorptive nonlinear optical properties of deoxyribonucleic acid (DNA)–cetyltrimethylammonium chloride (CTMA) biopolymer functionalized with spirulina natural dye, as solutions in butanol, and on the same nonlinear optical properties of similar solutions with spirulina only, are presented. The spectroscopic characterisation of the investigated complexes is performed by Ultraviolet–Visible-Near-Infrared (UV-VIS-NIR) spectroscopy and Attenuated Total Reflection Fourier-transform Infrared (ATR-FTIR) spectroscopy. Their optical limiting functionality is experimentally demonstrated at the wavelength of 1550 nm (an important telecommunication wavelength) using ultrashort laser pulses (~120 fs). Important parameters that characterise the optical limiting (nonlinear absorption coefficient β, and saturation intensity, I_sat) are determined by the Intensity-scan (I-scan) method in the investigated materials. The results of our experimental investigation reveal, for the first time to the best of our knowledge, a significant absorptive nonlinear optical response of spirulina natural dye and its potential for optical limiting. The favourable effect of the DNA biopolymer on the nonlinear optical response of the investigated solutions, resulting in the enhancement of their nonlinear optical properties, is demonstrated. Thus, the investigated DNA–CTMA–spirulina liquid compound is a promising novel “green” material for passive optical limiting devices to protect sensitive optical and optoelectronic devices from high-intensity near-infrared laser beams. Also, from dye-doped DNA compounds as solutions it is possible to obtain, by different methods (e.g., spin-coating, drop casting), thin films as the base of all-optical solid-state limiting devices. Full article

Gold nanoparticles (AuNPs) are widely employed in biosensors; however, conventional synthesis methods require additional surface modification to confer colloidal stability and bioconjugation capability. Here, we report a facile strategy to synthesize carboxymethyl dextran (CMD)-coated AuNPs (AuNP@CMD) that simultaneously serve as a plasmonic label, a stabilizing agent, and a functional scaffold. The CMD was prepared directly via partial carboxymethylation of dextran in a one-pot reduction of HAuCl₄, enabling the synthesis of AuNP@CMD with tunable particle sizes and excellent colloidal stability for at least one month at 4 °C. The CMD coating on AuNPs can prevent nanoparticle aggregation, suppress nonspecific adsorption, and introduce surface carboxyl groups for conjugation of bioprobes. Such characteristics are important to develop plasmonic nanoparticle-linked sorbent assays as an alternative to the conventional colorimetric enzyme-linked immunosorbent assay. When applied to a fiber-optic nanogold-linked sorbent assay, AuNP@CMD enabled ultrasensitive detection of a single-stranded DNA, achieving a detection limit at the femtomolar (fM) concentration level without nucleic acid amplification. Full article

Sweetpotato (Ipomoea batatas) is a staple crop of strategic importance in West Africa, particularly in Côte d’Ivoire. However, its productivity is increasingly under threat due to viral diseases. Given the lack of updated epidemiological data over the past three decades, a nationwide survey was conducted in September 2023 across 94 fields in 83 locations covering seven agroecological zones of the country. A total of 221 symptomatic and asymptomatic leaf samples were analyzed using PCR for DNA viruses and RT-PCR for RNA viruses. The overall viral incidence rate calculated was 65.61%, with significant regional variations (35–97.18%, p < 0.001) and notable differences in the severity of symptoms (p = 0.0095). Agroecological zone I was the most affected, while agroecological zones IV and V were the least impacted. Four viruses were identified: cucumber mosaic virus (CMV), sweet potato leaf curl virus (SPLCV), sweet potato feathery mottle virus (SPFMV), and sweet potato chlorotic stunt virus (SPCSV). No badnaviruses were found. CMV was the most common virus found in single infections (43.44%), followed by SPLCV (5.43%). SPFMV and SPCSV were only observed in mixed infections, particularly CMV/SPLCV (14.03%) and CMV/SPFMV (1.81%). Two triple infections were also detected: SPFMV/SPCSV/CMV and SPFMV/SPLCV/CMV. In total, 34 partial coat protein sequences were obtained (28 SPLCV, 4 SPFMV, 1 CMV, 1 SPCSV). Phylogenetic analysis revealed a high similarity between SPLCV isolates characterized in Côte d’Ivoire and those from Burkina Faso, Europe (Spain, Italy), and the Americas (USA, Puerto Rico) with nucleotide identity values ranging from 98% to 100%. The Côte d’Ivoire SPCSV sequence showed 97.92% nucleotide identity with European isolates, whereas SPFMV sequences exhibited greater diversity (77–89% identity) but clustered within the West African lineage. Sweetpotato viral diseases were detected mostly in mixed-cropping fields (66.85%). This work provides the first epidemiological update on sweetpotato viral diseases since 1987 and the first molecular evidence of the nationwide presence of SPLCV and SPCSV in Côte d’Ivoire. Full article

Sugarcane streak mosaic virus (SCSMV) is one of the mosaic viruses found in mixed infection with two or more viruses. Infections of mosaic viruses show highly similar mosaic symptoms and are difficult to distinguish. This study aimed to develop a specific antibody against SCSMV that could potentially be utilized to differentiate mosaic virus infections. The cDNA encoding the coat protein (CP) of SCSMV was isolated by RT-PCR from the symptomatic sugarcane leaves. The cDNA was then used for the production of CP for the development of its polyclonal antibody. The nucleotide sequence of the cDNA showed high homology of 94.2–97.3% at the amino acid level with the CP-cDNA of SCSMV isolated from India (AM749403.1), Africa (OR195142.1), and USA (U75456.1). CP was produced as a recombinant protein with a molecular size of 36.5 kDa in Escherichia coli. The injection of recombinant CP into a rabbit resulted in the production of polyclonal antibodies, which were used for the immunodetection of SCSMV in sugarcane. Immunoblot analysis revealed a specific reaction of SCSMV-CP in symptomatic sugarcane leaves. ELISA (Enzyme-Linked Immunosorbent Assay) and IC-RT-PCR (Immunocapture-Reverse Transcription-Polymerase Chain Reaction) using the CP antibody proved successful for detecting SCSMV infection in sugarcane leaves. The results indicate that the SCSMV-CP antibody is suitable for an immunodetection system and exhibits high specificity for SCSMV infection. Full article

The focus of this study was to explore phage display systems employing bacteriophage lambda (λ) gene fusions to its capsid decoration protein gpD as reagent tools for tackling disease. The biological activity of gpD-fusions was examined by testing for the retained antimicrobial toxicity of cathelicidins or defensins fused to gpD. Our previous finding that only COOH fusions of either cathelicidins or defensins to gpD were toxigenic was expanded to show that only the reduced form of fused defensin antimicrobial polypeptides was found to be toxigenic. Compared in review are gene-fusion lytic display systems (where the fusion-display gene is integrated within the viral genome) with a surrogate system, employed herein, that exogenously provides the fusion-display protein for addition to phage capsid. It is easily possible to produce fully coated lambda display particles (LDP) serving as single epitope vaccines (SEV), or antimicrobials, or to produce partially coated LDP without any complex bacteriophage genetic engineering, making the system available to all. The potential to build vaccine vector phage particles (LDNAP) comprising essentially sheathed DNA vaccines encapsulated within an environmentally protective capsid is described. LDNAP are produced by introducing a cassette into the phage genome either by phage–plasmid recombination or cloning. The cassette carries a high-level eukaryotic expression promoter driving transcription of the vaccine candidate gene and is devoid of plasmid resistance elements. Full article

We report an efficient, high-yield method for synthesizing dumbbell-shaped conjugates composed of gold nanoparticles (AuNPs) connected by double-stranded (ds) DNA. The dsDNA, bearing terminal thiol groups, was covalently attached to two AuNPs to form uniform constructs comprising either 15 nm or 25 nm particles bridged by 38 base pairs (bp) or 100 bp dsDNA. The dumbbells were purified by gel electrophoresis and exhibited high stability, remaining intact for several days in pure water or buffers at ambient temperature. Deposition onto solid substrates followed by drying, however, led to their partial structural collapse. TEM imaging showed that deposition on carbon grids typically yielded dumbbell structures with interparticle gaps of only 1–2 nm, suggesting that the dsDNA bridge contracts during deposition and drying. However, deposition on polylysine-coated mica for AFM imaging preserved the native geometry, with the gaps consistent with the expected DNA length. Our results reveal that deposition significantly affects the structure and integrity of dsDNA bridges in dumbbell constructs, highlighting the importance of appropriate substrate and surface coating selection for reliable characterization of DNA properties in dried dumbbells. Full article

Egg yolk IgY antibody has significant application potential in aquaculture as a form of passive immunotherapy against various bacterial infections owing to its capacity for large-scale and cost-effective production. In this research, laying hens were immunized with live or inactivated Aeromonas hydrophila to produce IgY antibodies. Following this, experiments were carried out to assess the passive immune protection rates of the two types of IgY antibodies when used to immunize goldfish (Carassius auratus), which were then infected with A. hydrophila or Aeromonas veronii. ELISA experiments were conducted to demonstrate the interaction between the IgY antibodies and the bacteria. The kidneys of C. auratus were coated on a Luria–Bertani (LB) medium to evaluate bacterial content. The leukocyte phagocytosis was detected by a cell phagocytosis assay. The serum of C. auratus was used to assess the expression of antioxidant factors, and a qRT-PCR was conducted to evaluate the mRNA expression of inflammatory factors in visceral tissue. Furthermore, histopathology and immunofluorescence analysis were performed to evaluate the structural integrity, apoptosis, and DNA damage of visceral tissues. The results indicated that the live or inactivated A. hydrophila IgY antibodies exhibited passive immune protection rates against A. hydrophila and A. veronii and could recognize these two bacteria in vitro. Additionally, these two IgY improved the phagocytic ability of leukocytes, diminished renal bacterial concentration, and decreased the levels of antioxidant factors and mRNA expression of inflammatory factors. Meanwhile, the two IgY antibodies did not cause any pathology of the kidney, spleen, and intestine, and decreased the levels of DNA damage factor (γH2A.X) and cell apoptosis factor (p53) in renal tissue. Therefore, live and inactivated A. hydrophila IgY antibodies can resist bacterial infections, with live bacteria IgY providing greater protection than inactivated bacteria IgY. Further, A. hydrophila is an aquatic pathogen that causes minimal damage to laying hens, and the immunity of live A. hydrophila conforms to animal welfare. Altogether, live A. hydrophila IgY antibody can serve as a polyvalent passive immune vaccine candidate in aquaculture. Full article