Search Results (603)

A key obstacle to the efficacy of cancer drugs is the safe delivery of the drugs to the target site of the disease. Recent advances in nanomedicine have introduced smart hydrogel nanoparticles as promising, efficient, secure, and stimulus-responsive drug carriers. Herein, a bio-safe pH-sensitive nanohydrogel (NG) made of polyaminoethyl methacrylamide (AEMA)-grafted dextran was used as a carrier for liver-targeted doxorubicin (DOX) delivery. Lactobionate (SL) residue was conjugated to the prepared NG as a targeting agent, and DOX was also conjugated via Schiff base linkage. The synthesized structure was analyzed using ¹HNMR, FT-IR, and size exclusion chromatography. DOX release was confirmed through UV-Vis spectroscopy. A pH-responsive manner in the DOX release profile was observed in a simulated medium with pH changes. In vitro toxicity assessment was performed in HepG2 and L929 cell lines, which have demonstrated the biosafety of the prepared hydrogel and its high effectiveness as an anticancer drug delivery system. Full article

We report a rapid aqueous method for synthesizing monodisperse gold nanoparticles (AuNPs), employing 2-propynylamine as both an intrinsic reducing agent and a surface-stabilizing ligand. This self-mediated process—achieved in a single step—yields spherical AuNPs with an average diameter of 4.0 ± 1.0 nm and a well-defined localized surface plasmon resonance band centered at 520 nm. Acting as a bifunctional molecule, 2-propynylamine simultaneously reduces HAuCl₄·3H₂O to elemental gold and passivates the nanoparticle surface through coordination via the amine group, while preserving a terminal alkyne (–C≡CH) functionality. This reactive moiety remains exposed and chemically accessible, enabling post-synthetic modification through Cu(I)-catalyzed azide–alkyne cycloaddition. Control experiments using alternate milling times and vial composition confirmed the essential role of 2-propynylamine in mediating both reduction and surface functionalization. The resulting alkyne-functionalized AuNPs serve as versatile “click-ready” platforms for bioconjugation, sensing, and advanced material assembly. Overall, this scalable, green approach eliminates the need for external reducing or capping agents and provides a modular route to chemically addressable nanomaterials with tunable surface reactivity. Full article

Carbon nanotubes have shown great promise in drug delivery systems as they can easily penetrate the cell membrane. Herein, carbon nanotubes functionalized with polyethylene glycol and folic acid were used to improve target specificity in breast and colon cancer cells. The functionalized carbon nanotubes were bioconjugated with bioactive compounds from plant extracts. In vitro cytotoxicity studies were conducted to demonstrate cellular uptake and apoptosis due to bioconjugate cellular internalization. The bioconjugates were able to preserve normal cells and induce cell death in cancer cells. The efficacy of the carbon nanotube bioconjugates in this study shows great potential in cancer therapy applications. Full article

Background/Objectives: Bio-produced gold nanoparticles (AuNPs) are effective carriers of short RNAs into specialized mammalian cells. Their potential application is still limited by scarce knowledge on their uptake and intracellular fate. Gold nanoparticles that are not biologically produced (NB-AuNPs) enter specialized cells primarily via clathrin-dependent endocytosis. Unlike the NB-AuNPs, the bio AuNPs possess natural surface coatings that significantly alter the AuNPs properties. Our research aimed to reveal the cellular uptake of the AuNPs with respect to delivering a functional RNA cargo. Methods: The AuNPs were conjugated with short inhibitory RNA specific to miR 135b. Mammary cancer cells 4T1 were pretreated with inhibitors of caveolin- and clathrin-mediated endocytosis and macropinocytosis. AuNPs’ uptake, fate, and miR 135b knock-down were assessed with TEM and qPCR. Results: The AuNPs-antimiR 135b conjugates entered 4T1 cells via all the tested pathways and could be seen inside the cells in early and late endosomes as well as cytoplasm. In contrast to the clathrin-dependent pathway, the caveolae-mediated endocytosis and the macropinocytosis of the AuNPs resulted in the effective targeting and reduction of the miR 135b. Conclusions: The bio-produced AuNPs can effectively enter mammalian cells simultaneously by different endocytic pathways but the delivery of functional cargo is not achieved via the clathrin-dependent endocytosis. Full article

The objective of this study was to investigate the epidemiology of Fasciola hepatica in Cervus elaphus kept in natural conditions in the Riaño Regional Hunting Reserve, north-west of Spain, where several species of domestic and wild animals coexist. One hundred red deer were examined and classified according to age, sex, and sampling season. After the necropsy of the animals, the liver was removed and inspected to obtain the adult parasites of F. hepatica. Faecal samples were collected and processed using the coprological sedimentation technique. The prevalence of this trematode by necropsy was 12%, with a low number of specimens per animal ($\overline{\mathrm{x}}$ = 2.7 ± 1.5; range 1–6). The young animals and the males had a higher prevalence than the adults and the females, finding statistically significant differences only according to the host age. Significant variations were also observed when considering the seasons of the year, with the highest number of infected animals in spring. The histopathological study revealed the presence of lesions compatible with a chronic fasciolosis similar to that found in domestic animals. The shedding of F. hepatica eggs was quite low in terms of prevalence (6%) and mean intensity of infection ($\overline{\mathrm{x}}$ = 27.3 ± 20.6, range 4–60 epg), being in young animals, in males, and in spring, where the greatest excretion of eggs was observed. These results suggest that the deer are suitable definitive hosts for F. hepatica in the northwest of the Iberian Peninsula, but they are unusual hosts. The serum samples were analysed using a native excretory/secretory antigen (FhES) and a 2.9 kDa recombinant protein (FhrAPS) used for diagnosis of early and current fasciolosis in livestock. A commercial kit for serodiagnosis of F. hepatica in sheep and cattle, based on a monoclonal antibody (BIO K 211), was also evaluated in red deer. The seroprevalence of seropositivity of F. hepatica by FhES-ELISA was 32%, by FhrAPS-ELISA 13%, and by BIO K 211, 9%. In the three serological tests, the seroprevalence obtained was higher in adult animals, in males, and in spring. In the three serological tests used to understand the epidemiology of F. hepatica in red deer, we have observed that the sensitivity was low, perhaps due to the use of an anti-bovine IgG1 as a conjugate, so in future immunodiagnostic tests, it would be more desirable to obtain an anti-deer IgG, probably achieving better results. Due to these results, it is essential to investigate other serological or molecular tests that allow us to know the real importance of F. hepatica in deer and other wild animals. The role of deer as a reservoir of this trematode does not appear to be very important. Full article

Sugar amino acids (SAAs) represent a privileged class of molecular chimeras that uniquely merge the structural rigidity of carbohydrates with the functional display of amino acids. These hybrid molecules have garnered significant attention as programmable conformational constraints, offering a powerful strategy to overcome the inherent limitations of peptide-based therapeutics, such as proteolytic instability and conformational ambiguity. The strategic incorporation of SAAs into peptide backbones, particularly within cyclic frameworks, allows for the rational design of peptidomimetics with pre-organized secondary structures, enhanced metabolic stability, and improved physicochemical properties. This review provides a comprehensive analysis of the synthetic methodologies developed to access the diverse structural landscape of SAAs, with a focus on modern, stereoselective strategies that yield versatile building blocks for peptide chemistry. A critical examination of the structural impact of SAA incorporation reveals their profound ability to induce and stabilize specific secondary structures, such as β- and γ-turns. Furthermore, a comparative analysis positions SAAs in the context of other widely used peptidomimetic scaffolds, highlighting their unique advantages in combining conformational control with tunable hydrophilicity. We surveyed the application of SAA-containing cyclic peptides as therapeutic agents, with a detailed case study on gramicidin S analogs that underscores the power of SAAs in elucidating complex structure–activity relationships. Finally, this review presents a forward-looking perspective on the challenges and future directions of the field, emphasizing the transformative potential of computational design, artificial intelligence, and advanced bioconjugation techniques to accelerate the development of next-generation SAA-based therapeutics. Full article

The development of low-background, facile, and robust fluorescent nanoprobes for imaging and monitoring of intracellular mRNA changes remains a great challenge. Taking advantage of the high fluorescence quenching efficiency of core-shell gold@polydopamine (Au@PDA) nanocomposites and Ca²⁺-promoting DNA adsorption stability, a simple and universal bioconjugate strategy was designed to a construct fluorescent nanoprobe for highly efficient tumor-related mRNA imaging. The fluorescence of Cy5-labeled DNA was quenched up to 92.38% by the AuNP and PDA via nanometal surface energy transfer (NSET) and photoinduced electron transfer (PET), respectively. TK1 mRNA, a biomarker of tumor growth, initiates hybridization and results in fluorescence recovery, which built the foundation for identifying the expression level changes in living cells. More importantly, three kinds of tumor-related mRNA (TK1 mRNA, GalNAc-T mRNA, and C-myc mRNA) can be detected simultaneously with different fluorophore-modified recognition sequences, which can avoid false positive signals and improve the reliability of cancer diagnostic, holding great promise for cancer diagnosis, prognosis, and therapy. Full article

Because allopregnanolone and derivatives represent biologically active molecules, in this letter, we present the synthesis of a new bioconjugate steroid pyridinium salt derived from allopregnanolone in three steps. The key steps involve the formation of the hydrazone intermediate, followed by condensation with bromoacetyl bromide and subsequent coupling with pyridine to generate the pyridinium bromide salt. The new bioconjugate steroid pyridinium salt, 4, was fully characterized by proton and carbon nuclear magnetic resonance (¹H and ¹³C NMR) spectroscopy, mass spectrometry (MS), and Fourier transform infrared spectroscopy (FTIR). ¹H-NMR analysis revealed the presence of a dynamic rotameric mixture in a 7:3 ratio of Z/E amide conformers, which were identified by a 2D NOESY experiment. Full article

Overexpression of αvβ3 integrin is found in a diverse group of tumors originating from glial cells in the brain, making this transmembrane receptor a promising biomarker for molecular MRI diagnosis. In the study, we conjugated a monoclonal antibody against the β3 subunit (CD61) of the αvβ3 integrin receptor with carbon-encapsulated iron nanoparticles to yield Fe@C-(CH₂)₂-CONH-anti-CD61 bioconjugates that were used in dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Wistar rats bearing C6 gliomas were injected as a single bolus (0.5 mL) through the tail vain with a suspension of Fe@C-(CH₂)₂-CONH-anti-CD61 nanoparticles (200 μg mL⁻¹) and the animals were imaged using the T2*-weighted echo planar imaging (T2* EPI) technique. Results showed that intravenously infused nanoparticles targeting αvβ3 integrin receptors provide strong contrast in rat glioma tissues. No such effects were observed in other rat organs, although some post-contrast effects were also noted in the liver and kidney. The study shows that the as-developed nanoparticles decorated with anti-CD61 monoclonal antibodies might be considered as a novel contrast candidate for noninvasive DSC-MRI diagnosis in CD61-positive gliomas. Full article

We report herein the development of a polyclonal antibody against ochratoxin A (OTA) using a specially designed synthetic OTA derivative as the immunizing hapten. This OTA derivative contains a tetrapeptide linker (glycyl-glycyl-glycyl-lysine, GGGK), through which it can be linked to a carrier protein and form an immunogenic conjugate. The OTA derivative (OTA-glycyl-glycyl-glycyl-lysine, OTA-GGGK) has been synthesized on a commercially available resin via the well-established Fmoc-based solid-phase peptide synthesis (Fmoc-SPPS) strategy; overall, this approach has allowed us to avoid tedious liquid-phase synthesis protocols, which are often characterized by multiple steps, several intermediate products and low overall yield. Subsequently, OTA-GGGK was conjugated to bovine thyroglobulin through glutaraldehyde, and the conjugate was used in an immunization protocol. The antiserum obtained was evaluated with a simple-format ELISA in terms of its titer and capability of recognizing the natural free hapten; the anti-OTA antibody, as a whole IgG fragment, was successfully applied to three different immunoanalytical systems for determining OTA in various food materials and wine samples, i.e., a multi-mycotoxin microarray bio-platform, an optical immunosensor, and a biotin–streptavidin ELISA, which has proved the analytical effectiveness and versatility of the anti-OTA antibody developed. The same approach may be followed for developing antibodies against other low-molecular-weight toxins and hazardous substances. Full article

Background/Objectives: Extracellular vesicles (EVs) are involved in cell-to-cell communication and delivery of signaling molecules and represent an interesting approach in targeted therapy. This project focused on EV-mediated facilitation and cell-specific delivery of effector antimiR molecules carried by biologically produced gold nanoparticles (AuNPs). Methods: First, we loaded EVs derived from cancer cells 4T1 with AuNPs-antimiR. The AuNPs were also decorated with or without transferrin (Tf) molecules. We examined parental cell-specific delivery of the AuNPs-Tf-antimiR within monocultures as well as co-cultures in vitro. Subsequently, we used autologous EVs containing AuNPs-Tf-antimiR to target tumor cells in a xenograft tumor model in vivo. Efficacy of the antimir transfer was assessed by qPCR and apoptosis assessment. Results: In vitro, EVs loaded with AuNPs-antimiR were internalized only by the parental cells and the AuNPs-antimiR transfer was successful and effective only in EVs that were decorated with Tf. We achieved effective delivery of the antimiR molecule into cancer cells in vivo, which was proved by specific silencing of the target oncogenic miRNA as well as induction of cancer cells apoptosis. Conclusions: EVs represent an interesting and potent way for targeted cargo delivery and personalized medicine. On the other hand, there are various safety and efficacy challenges that remain to be addressed. Full article

Oral administration remains the preferred drug delivery route but faces formidable gastrointestinal barriers, including enzymatic degradation, solubility limitations, and poor epithelial absorption. Zein-based nanocarriers (ZBNs), derived from maize prolamin, provide a transformative platform to address these challenges. This review synthesizes recent advances in ZBNs’ design, highlighting their intrinsic advantages: structural stability across pH gradients, self-assembly versatility, and a surface functionalization capacity. Critically, we detail how engineered ZBNs overcome key barriers, such as enzymatic/chemical protection via hydrophobic encapsulation, the enhanced mucus penetration or adhesion through surface engineering, and improved epithelial transport via ligand conjugation. Applications demonstrate their efficacy in stabilizing labile therapeutics, enhancing the solubility of BCS Class II/IV drugs, enabling pH-responsive release, and significantly boosting oral bioavailability. Remaining challenges in scalability and translational predictability warrant future efforts toward multifunctional systems, bio-interfacial modeling, and continuous manufacturing. This work positions ZBNs as a potential platform for the oral delivery of BCS Class II–IV drugs’ in the biopharmaceutics classification system. Full article

Background: Hydrogels are 3D networks of hydrophilic polymers with various biomedical applications, including tissue regeneration, wound healing, and localized drug delivery. Hydrogel conjugation links therapeutic agents to a hydrogel network, creating a delivery system with adjustable and flexible hydrogel properties and drug activity, allowing for controlled release and enhanced drug stability. Conjugating therapeutic agents to hydrogels provides innovative delivery formats, including injectable and sprayable dosage forms, which facilitate localized and long-lasting delivery. This approach enables non-viral therapeutic methods, such as insertional mutagenesis, and minimally invasive drug administration. Scope and Objectives: While numerous reviews have analyzed advancements in hydrogel synthesis, characterization, properties, and hydrogels as a drug delivery vehicle, this review focuses on hydrogel conjugation, which enables the precise functionalization of hydrogels with small molecules and macromolecules. Subsequently, a description and discussion of several bio-conjugated hydrogel systems, as well as binding motifs (e.g., “click” chemistry, functional group coupling, enzymatic ligation, etc.) and their potential for clinical translation, are provided. In addition, the integration of therapeutic agents with nucleic acid-based hydrogels can be leveraged for sequence-specific binding, representing a leap forward in biomaterials. Key findings: Special attention was given to the latest conjugation approaches and binding motifs that are useful for designing hydrogel-based drug delivery systems. The review systematically categorizes hydrogel conjugates for drug delivery, focusing on conjugating hydrogels with major classes of therapeutic agents, including small-molecule drugs, nucleic acids, proteins, etc., each with distinct conjugation challenges. The design principles were discussed along with their properties and drug release profiles. Finally, future opportunities and current limitations of conjugated hydrogel systems are addressed. Full article

Glycoconjugate vaccines, consisting of a protein component covalently linked to a glycan antigen, have led to a significant reduction in the global occurrence of bacterial meningitis and pneumonia. They provide robust, lasting immunity in all age groups. However, their production by traditional chemical conjugation approaches has drawbacks in terms of complexity, cost, and lack of flexibility in design, which explains their limited application to a few pathogenic bacteria in the past four decades. Protein glycan coupling technology (PGCT) or bioconjugation, where glycoconjugates are produced in purpose-engineered bacterial cells, is a useful alternative to chemical conjugation and promises an array of low-cost custom-made glycoconjugate vaccines with vast protein glycan combinations. The technology has undergone significant development since its inception, and new advances and refinements continually drive the field forward. Several bioconjugate vaccines are currently in clinical trials, demonstrating the potential of the technology. We will review the wide applicability of bioconjugation and recent developments in each of the components of the technology, namely, glycan expression, protein selection, and the coupling of selected glycan with proteins, all within custom-designed E. coli cells. These advances promise to deliver effective glycoconjugate vaccines for multiple unmet medical needs. Full article

Background/Objectives: Rapid development of vaccines against SARS-CoV-2 was pivotal to controlling the COVID-19 pandemic. The emergency also provided a rare opportunity to test novel vaccine platforms such as mRNA in large clinical trials. Most of the early vaccines used SARS-CoV-2 Spike protein as the target antigen. Nevertheless, subsequent studies have shown that Receptor Binding Domain (RBD) of Spike also can yield efficacious vaccines, and we previously demonstrated that chemical conjugation of RBD to a carrier protein, EcoCRM^®, enhanced antibody responses and induced strong virus neutralization activity in mice. Methods: Here, we compared the immunogenicity of this conjugate to that of an approved mRNA vaccine from Pfizer/BioNTech in rhesus macaques over a period of nine months. Results: AS01-adjuvanted RBD conjugate induced a similar or better antibody response, receptor binding inhibition, and virus neutralization activity against different variants of SARS-CoV-2, compared to mRNA. IgG subclass profiles induced by conjugate and mRNA vaccines were initially dominated by IgG1 and IgG3 then switched to IgG2 and IgG4 dominant profiles during the subsequent six-month period. Polyclonal immune sera from the conjugate and mRNA had similar antibody avidity at multiple time points. Conclusions: In summary, antibody responses in rhesus macaques induced by the RBD-EcoCRM conjugate and the Spike mRNA vaccine are very similar. These results demonstrate the potential for the RBD-EcoCRM conjugate as a vaccine against SARS-CoV-2. Full article