Computational Simulation of Colorectal Cancer Biomarker Particle Mobility in a 3D Model.

Even though some methods for the detection of colorectal cancer have been used clinically, most of the techniques used do not consider the in situ detection of colorectal cancer (CRC) biomarkers, which would favor in vivo real-time monitoring of the carcinogenesis process and consequent studies of the disease. In order to give a scientific and computational framework ideal for the evaluation of diagnosis techniques based on the early detection of biomarker molecules modeled as spherical particles from the computational point of view, a computational representation of the rectum, stool and biomarker particles was developed. As consequence of the transport of stool, there was a displacement of CRC biomarker particles that entered the system as a result of the cellular apoptosis processes in polyps with a length lower than 1 cm, reaching a maximum velocity of 3.47×10-3 m/s. The biomarkers studied showed trajectories distant to regions of the polyp of origin in 1 min of simulation. The research results show that the biomarker particles for CRC respond to the variations in the movements of the stool with trajectories and speeds that depend on the location of the injury, which will allow locating the regions with the highest possibilities of catching particles through in situ measurement instruments in the future.

Short Antimicrobial Peptide Derived from the Venom Gland Transcriptome of Pamphobeteus verdolaga Increases Gentamicin Susceptibility of Multidrug-Resistant Klebsiella pneumoniae.

Infectious diseases account for nine percent of annual human deaths, and the widespread emergence of antimicrobial resistances threatens to significantly increase this number in the coming decades. The prospect of antimicrobial peptides (AMPs) derived from venomous animals presents an interesting alternative for developing novel active pharmaceutical ingredients (APIs). Small, cationic and amphiphilic peptides were predicted from the venom gland transcriptome of Pamphobeteus verdolaga using a custom database of the arthropod's AMPs. Ninety-four candidates were chemically synthesized and screened against ATCC® strains of Escherichia coli and Staphylococcus aureus. Among them, one AMP, named PvAMP66, showed broad-spectrum antimicrobial properties with selectivity towards Gram-negative bacteria. It also exhibited activity against Pseudomonas aeruginosa, as well as both an ATCC® and a clinically isolated multidrug-resistant (MDR) strain of K. pneumoniae. The scanning electron microscopy analysis revealed that PvAMP66 induced morphological changes of the MDR K. pneumoniae strain suggesting a potential "carpet model" mechanism of action. The isobologram analysis showed an additive interaction between PvAMP66 and gentamicin in inhibiting the growth of MDR K. pneumoniae, leading to a ten-fold reduction in gentamicin's effective concentration. A cytotoxicity against erythrocytes or peripheral blood mononuclear cells was observed at concentrations three to thirteen-fold higher than those exhibited against the evaluated bacterial strains. This evidence suggests that PvAMP66 can serve as a template for the development of AMPs with enhanced activity and deserves further pre-clinical studies as an API in combination therapy.

Cytotoxicity and Genotoxicity of Azobenzene-Based Polymeric Nanocarriers for Phototriggered Drug Release and Biomedical Applications.

Drug nanoencapsulation increases the availability, pharmacokinetics, and concentration efficiency for therapeutic regimes. Azobenzene light-responsive molecules experience a hydrophobicity change from a polar to an apolar tendency by trans-cis photoisomerization upon UV irradiation. Polymeric photoresponse nanoparticles (PPNPs) based on azobenzene compounds and biopolymers such as chitosan derivatives show prospects of photodelivering drugs into cells with accelerated kinetics, enhancing their therapeutic effect. PPNP biocompatibility studies detect the safe concentrations for their administration and reduce the chance of side effects, improving the effectiveness of a potential treatment. Here, we report on a PPNP biocompatibility evaluation of viability and the first genotoxicity study of azobenzene-based PPNPs. Cell line models from human ventricular cardiomyocytes (RL14), as well as mouse fibroblasts (NIH3T3) as proof of concept, were exposed to different concentrations of azobenzene-based PPNPs and their precursors to evaluate the consequences on mitochondrial metabolism (MTT assay), the number of viable cells (trypan blue exclusion test), and deoxyribonucleic acid (DNA) damage (comet assay). Lethal concentrations of 50 (LC50) of the PPNPs and their precursors were higher than the required drug release and synthesis concentrations. The PPNPs affected the cell membrane at concentrations higher than 2 mg/mL, and lower concentrations exhibited lesser damage to cellular genetic material. An azobenzene derivative functionalized with a biopolymer to assemble PPNPs demonstrated biocompatibility with the evaluated cell lines. The PPNPs encapsulated Nile red and dofetilide separately as model and antiarrhythmic drugs, respectively, and delivered upon UV irradiation, proving the phototriggered drug release concept. Biocompatible PPNPs are a promising technology for fast drug release with high cell interaction opening new opportunities for azobenzene biomedical applications.

Photosensitive nanocarriers for specific delivery of cargo into cells.

Nanoencapsulation is a rapidly expanding technology to enclose cargo into inert material at the nanoscale size, which protects cargo from degradation, improves bioavailability and allows for controlled release. Encapsulation of drugs into functional nanocarriers enhances their specificity, targeting ability, efficiency, and effectiveness. Functionality may come from cell targeting biomolecules that direct nanocarriers to a specific cell or tissue. Delivery is usually mediated by diffusion and erosion mechanisms, but in some cases, this is not sufficient to reach the expected therapeutic effects. This work reports on the development of a new photoresponsive polymeric nanocarrier (PNc)-based nanobioconjugate (NBc) for specific photo-delivery of cargo into target cells. We readily synthesized the PNcs by modification of chitosan with ultraviolet (UV)-photosensitive azobenzene molecules, with Nile red and dofetilide as cargo models to prove the encapsulation/release concept. The PNcs were further functionalized with the cardiac targeting transmembrane peptide and efficiently internalized into cardiomyocytes, as a cell line model. Intracellular cargo-release was dramatically accelerated upon a very short UV-light irradiation time. Delivering cargo in a time-space controlled fashion by means of NBcs is a promising strategy to increase the intracellular cargo concentration, to decrease dose and cargo side effects, thereby improving the effectiveness of a therapeutic regime.