Hybrid Complexes of Photosensitizers with Luminescent Nanoparticles: Design of the Structure

Increasing the efficiency of the photodynamic action of the dyes used in photodynamic therapy is crucial in the field of modern biomedicine. There are two main approaches used to increase the efficiency of photosensitizers. The first one is targeted delivery to the object of photodynamic action, while the second one is increasing the absorption capacity of the molecule. Both approaches can be implemented by producing dyenanoparticle conjugates. In this review, we focus on the features of the latter approach, when nanoparticles act as a light-harvesting agent and nonradiatively transfer the electronic excitation energy to a photosensitizer molecule. We will consider the hybrid photosensitizerquantum dot complexes with energy transfer occurring according to the inductive-resonance mechanism as an example. The principle consisting in optimizing the design of hybrid complexes is proposed after an analysis of the published data; the parameters affecting the efficiency of energy transfer and the generation of reactive oxygen species in such systems are described.

Hyaluronan and Derivatives: An In Vitro Multilevel Assessment of Their Potential in Viscosupplementation

In this research work, viscosupplements based on linear, derivatized, crosslinked and complexed HA forms were extensively examined, providing data on the hydrodynamic parameters for the water-soluble-HA-fraction, rheology, sensitivity to enzymatic hydrolysis and capacity to modulate specific biomarkers’ expression in human pathological chondrocytes and synoviocytes. Soluble HA ranged from 0 to 32 mg/mL and from 150 to 1330 kDa MW. The rheological behavior spanned from purely elastic to viscoelastic, suggesting the diversity of the categories that are suitable for restoring specific/different features of the healthy synovial fluid. The rheological parameters were reduced in a diverse manner upon dilution and hyaluronidases action, indicating different durations of the viscosupplementation effect. Bioactivity was found for all the samples, increasing the expression of different matrix markers (e.g., hyaluronan-synthase); however, the hybrid cooperative complexes performed better in most of the experiments. Hybrid cooperative complexes improved COLII mRNA expression (~12-fold increase vs. CTR), proved the most effective at preserving cell phenotype. In addition, in these models, the HA samples reduced inflammation. IL-6 was down-regulated vs. CTR by linear and chemically modified HA, and especially by hybrid complexes. The results represent the first comprehensive panel of data directly comparing the diverse HA forms for intra-articular injections and provide valuable information for tailoring products’ clinical use as well as for designing new, highly performing HA-formulations that can address specific needs.

Immobilization of Phospholipase A1 Using a Protein-Inorganic Hybrid System

In this study, four kinds of phospholipase A1-metal (Al/Co/Cu/Mn) hybrid nanostructures were prepared for enhancing the stability of the free PLA1. The formed hybrid complexes were characterized by scanning electron microscope (SEM), Fourier infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The stability and substrate specificity of immobilized enzymes were subsequently determined. After immobilization, the temperature tolerance of PLA1–metal hybrid nanostructures was enhanced. The relative activity of PLA1–Al/Co/Cu hybrid nanostructures remained above 60% at 50 °C, while that of free enzyme was below 5%. The thermal transition temperature measured by differential scanning calorimetry (DSC) was found to increase from 65.59 °C (free enzyme) to 173.14 °C, 123.67 °C, 96.31 °C, and 114.79 °C, referring to PLA1–Cu/Co/Al/Mn hybrid nanostructures, respectively. Additionally, after a storage for fourteen days at 4 °C, the immobilized enzymes could exhibit approximately 60% of the initial activity, while the free PLA1 was inactivated after four days of storage. In brief, using Co2+, Cu2+, Al3+, and Mn2+ as the hybridization materials for immobilization could improve the catalytic properties and stability of the free PLA1, suggesting a promising method for a wider application of PLA1 in many fields such as food, cosmetics, and the pharmaceutical industry.

Evolution of the Hyaluronic Acid in Viscosupplementation – from Linear Particles to Hybrid Complexes

The discovery of unique properties of the hyaluronic acid and learning about the role of this aid in pathophysiology of extracellular matrices resulted in using this substance in pharmacological support in cases of tissue dysfunction due to numerous disease units. Therefore, the products containing this substance are now widely used in medicine including dermatology and aesthetic medicine, ophthalmology, facial-mandibular surgery and orthopedics, being among the most effective products used in the treatment of numerous cases of function impairment and deformation of tissues and organs. There are applied in both post-traumatic and post-inflammatory conditions as well as in symptoms due to chronic conditions. Their therapeutic effects result from joint surface moisturizing, reduction of the coefficient of friction (COF) and good bio-tolerance and biocompatibility confirmed by a low percentage of side effects and biocompatibility. The introduction of hyaluronic acid hybrid complexes with high and low molecular mass (H/L-HA) has increased the clinical usefulness of hyaluronic acid products thanks to their increased viscoelasticity, increased anti-inflammatory and chondroprotective properties and thermodynamic stabilization of the product guaranteeing its half-life. Thanks to the above mentioned pro­perties it becomes more effective in the non-surgical treatment of osteoarthritis.

Catalytic amplification by transition-state molecular switches for direct and sensitive detection of SARS-CoV-2

Despite the importance of nucleic acid testing in managing the COVID-19 pandemic, current detection approaches remain limited due to their high complexity and extensive processing. Here, we describe a molecular nanotechnology that enables direct and sensitive detection of viral RNA targets in native clinical samples. The technology, termed catalytic amplification by transition-state molecular switch (CATCH), leverages DNA-enzyme hybrid complexes to form a molecular switch. By ratiometric tuning of its constituents, the multicomponent molecular switch is prepared in a hyperresponsive state—the transition state—that can be readily activated upon the binding of sparse RNA targets to turn on substantial enzymatic activity. CATCH thus achieves superior performance (~8 RNA copies/μl), direct fluorescence detection that bypasses all steps of PCR (<1 hour at room temperature), and versatile implementation (high-throughput 96-well format and portable microfluidic assay). When applied for clinical COVID-19 diagnostics, CATCH demonstrated direct and accurate detection in minimally processed patient swab samples.

The desalting/salting pathway: a route to form metastable aggregates with tuneable morphologies and lifetimes

We investigate the formation/re-dissociation mechanisms of hybrid complexes made from negatively charged PAA2k coated γ-Fe2O3 nanoparticles (NP) and positively charged polycations (PDADMAC) in aqueous solution in the regime of very...

Symbiotic Assembly of Peptide Nano-Mosaics at Solid Interfaces

The spontaneous co-organization of distinct biomolecules at interfaces enables many of Nature’s hierarchical organizations involving both hard and soft materials. Engineering efforts to mimic such hybrid complexes rely on our...