Nanoarchitectonics of Bactericidal Coatings Based on CaCO-Nanosilver Hybrids.

Antimicrobial coatings provide protection against microbes colonization on surfaces. This can prevent the stabilization and proliferation of microorganisms. The ever-increasing levels of microbial resistance to antimicrobials are urging the development of alternative types of compounds that are potent across broad spectra of microorganisms and target different pathways.

Comparative Characterization of Iron and Silver Nanoparticles: Extract-Stabilized and Classical Synthesis Methods.

Synthesis of silver nanoparticles using extracts from plants is an advantageous technological alternative to the traditional colloidal synthesis due to its simplicity, low cost, and the inclusion of environmentally friendly processes to obtain a new generation of antimicrobial compounds. The work describes the production of silver and iron nanoparticles using sphagnum extract as well as traditional synthesis. Dynamic light scattering (DLS) and laser doppler velocimetry methods, UV-visible spectroscopy, transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), dark-field hyperspectral microscopy, and Fourier-transform infrared spectroscopy (FT-IR) were used to study the structure and properties of synthesized nanoparticles.

How similar is the antibacterial activity of silver nanoparticles coated with different capping agents?

Silver nanoparticles (AgNPs) represent one of the most commercialised metal nanomaterials, with an extensive number of applications that span from antimicrobial products to electronics. Bare AgNPs are very susceptible to aggregation, and capping agents are required for their protection and stabilisation. The capping agents can endow new characteristics which can either improve or deteriorate AgNPs (bio)activity.

Hierarchy of hybrid materials. Part-II: The place of organics--inorganics in it, their composition and applications.

Hybrid materials or hybrids incorporating organic and inorganic constituents are emerging as a very potent and promising class of materials due to the diverse but complementary nature of their properties. This complementarity leads to a perfect synergy of properties of the desired materials and products as well as to an extensive range of their application areas. Recently, we have overviewed and classified hybrid materials describing inorganics--organics in Part-I (Saveleva, et al.

A lipid membrane supported on an artificial extracellular matrix made of polyelectrolyte multilayers: towards nanoarchitectonics at the cellular interface.

To implement a specific function, cells recognize multiple physical and chemical cues and exhibit molecular responses at their interfaces - the boundary regions between the cell lipid-based membrane and the surrounding extracellular matrix (ECM). Mimicking the cellular external microenvironment presents a big challenge in nanoarchitectonics due to the complexity of the ECM and lipid membrane fragility. This study reports an approach for the assembly of a lipid bilayer, mimicking the cellular membrane, placed on top of a polyelectrolyte multilayer cushion made of hyaluronic acid and poly-L-lysine - a nanostructured biomaterial, which represents a 3D artificial ECM.

Spontaneous shrinkage drives macromolecule encapsulation into layer-by-layer assembled biopolymer microgels.

Hypothesis: Recently, the anomalous shrinkage of surface-supported hyaluronate/poly-l-lysine (HA/PLL) microgels (µ-gels), which exceeds that reported for any other multilayer-based systems, has been reported [1]. The current study investigates the capability of these unique µ-gels for the encapsulation and retention of macromolecules, and proposes the shrinkage-driven assembly of biopolymer-based µ-gels as a novel tool for one-step surface biofunctionalization.

Experiments: A set of dextrans (DEX) and their charged derivatives - carboxymethyl (CM)-DEX and diethylaminoethyl (DEAE)-DEX - has been utilized to evaluate the effects of macromolecular mass and net charge on µ-gel shrinkage and macromolecule entrapment.

Surface Modification with Particles Coated or Made of Polymer Multilayers.

The coating of particles or decomposable cores with polyelectrolytes via Layer-by-Layer (LbL) assembly creates free-standing LbL-coated functional particles. Due to the numerous functions that their polymers can bestow, the particles are preferentially selected for a plethora of applications, including, but not limited to coatings, cargo-carriers, drug delivery vehicles and fabric enhancements. The number of publications discussing the fabrication and usage of LbL-assembled particles has consistently increased over the last vicennial.

Vaterite vectors for the protection, storage and release of silver nanoparticles.

Silver nanoparticles (AgNPs) have found widespread commercial applications due to their unique physical and chemical properties. However, their relatively poor stability remains a main problem. An ideal way to improve the stability of AgNPs is not only to endow colloidal stability to individual nanoparticles but also to protect them from environmental factors that induce their agglomeration, like variation of ionic strength and pH, presence of macromolecules, etc.

Hybrid Mucin-Vaterite Microspheres for Delivery of Proteolytic Enzyme Chymotrypsin.

While the enteral delivery of proteolytic enzymes is widely established for combating many diseases as an alternative to antibiotic treatment, their local delivery only emerges as administration route enabling sustained release in a controlled manner on site. The latest requires the development of drug delivery systems suitable for encapsulation and preservation of enzymatic proteolytic activity. This study proposes hybrid microspheres made of mucin and biodegradable porous crystals of calcium carbonate (CC) as the carriers for chymotrypsin (CTR) delivery.

Biopolymer-Based Multilayer Capsules and Beads Made via Templating: Advantages, Hurdles and Perspectives.

One of the undeniable trends in modern bioengineering and nanotechnology is the use of various biomolecules, primarily of a polymeric nature, for the design and formulation of novel functional materials for controlled and targeted drug delivery, bioimaging and theranostics, tissue engineering, and other bioapplications. Biocompatibility, biodegradability, the possibility of replicating natural cellular microenvironments, and the minimal toxicity typical of biogenic polymers are features that have secured a growing interest in them as the building blocks for biomaterials of the fourth generation. Many recent studies showed the promise of the hard-templating approach for the fabrication of nano- and microparticles utilizing biopolymers.

Mesoporous One-Component Gold Microshells as 3D SERS Substrates.

Surface-enhanced Raman scattering (SERS) is a powerful analytical tool for label-free analysis that has found a broad spectrum of applications in material, chemical, and biomedical sciences. In recent years, a great interest has been witnessed in the rational design of SERS substrates to amplify Raman signals and optionally allow for the selective detection of analytes, which is especially essential and challenging for biomedical applications. In this study, hard templating of noble metals is proposed as a novel approach for the design of one-component tailor-made SERS platforms.

Pharmaceuticals Removal by Adsorption with Montmorillonite Nanoclay.

The problem of purifying domestic and hospital wastewater from pharmaceutical compounds is becoming more and more urgent every year, because of the continuous accumulation of chemical pollutants in the environment and the limited availability of freshwater resources. Clay adsorbents have been repeatedly proposed as adsorbents for treatment purposes, but natural clays are hydrophilic and can be inefficient for catching hydrophobic pharmaceuticals. In this paper, a comparison of adsorption properties of pristine montmorillonite (MMT) and montmorillonite modified with stearyl trimethyl ammonium (hydrophobic MMT-STA) towards carbamazepine, ibuprofen, and paracetamol pharmaceuticals was performed.

Which Biopolymers Are Better for the Fabrication of Multilayer Capsules? A Comparative Study Using Vaterite CaCO as Templates.

The polymer layer-by-layer assembly is accounted among the most attractive approaches for the design of advanced drug delivery platforms and biomimetic materials in 2D and 3D. The multilayer capsules can be made of synthetic or biologically relevant (, natural) polymers. The biopolymers are advantageous for bioapplications; however, the design of such "biocapsules" is more challengeable due to intrinsic complexity and lability of biopolymers.

Cooling-Triggered Release from Mesoporous Poly(-isopropylacrylamide) Microgels at Physiological Conditions.

Poly(-isopropylacrylamide) (pNIPAM) hydrogels have broad potential applications as drug delivery vehicles because of their thermoresponsive behavior. pNIPAM loading/release performances are directly affected by the gel network structure. Therefore, there is a need with the approaches for accurate design of 3D pNIPAM assemblies with the structure ordered at the nanoscale.

CaCO crystals as versatile carriers for controlled delivery of antimicrobials.

CaCO crystals have been known for a long time as naturally derived and simply fabricated nano(micro)-sized materials able to effectively host and release various molecules. This review summarises the use of CaCO crystals as versatile carriers to host, protect and release antimicrobials, offering a strong tool to tackle antimicrobial resistance, a serious global health problem. The main methods for the synthesis of CaCO crystals with different properties, as well as the approaches for the loading and release of antimicrobials are presented.

Layer-By-Layer Assemblies of Biopolymers: Build-Up, Mechanical Stability and Molecular Dynamics.

Rapid development of versatile layer-by-layer technology has resulted in important breakthroughs in the understanding of the nature of molecular interactions in multilayer assemblies made of polyelectrolytes. Nowadays, polyelectrolyte multilayers (PEM) are considered to be non-equilibrium and highly dynamic structures. High interest in biomedical applications of PEMs has attracted attention to PEMs made of biopolymers.

Inter-protein interactions govern protein loading into porous vaterite CaCO crystals.

The fast development of protein therapeutics has resulted in a high demand for advanced delivery carriers that can effectively host therapeutic proteins, preserve their bioactivity and release them on demand. Accordingly, vaterite CaCO crystals have attracted special attention as sacrificial templates for protein encapsulation in micro- and nanoparticles (capsules and beads, respectively) under mild biofriendly conditions. This study aimed to better understand the mechanism of protein loading into crystals as a primary step for protein encapsulation.

Editorial for the Special Issue on Self-Assembly of Polymers.

The self-assembly of polymers is a powerful tool for producing various functional materials with a high precision from nano- to macroscale [...

Bio-friendly encapsulation of superoxide dismutase into vaterite CaCO crystals. Enzyme activity, release mechanism, and perspectives for ophthalmology.

Mesoporous vaterite CaCO crystals are nowadays one of the most popular vectors for loading of fragile biomolecules like proteins due to biocompatibility, high loading capacity, cost effective and simple loading procedures. However, recent studies reported the reduction of bioactivity for protein encapsulation into the crystals in water due to rather high alkaline pH of about 10.3 caused by the crystal hydrolysis.

Porous Alginate Scaffolds Assembled Using Vaterite CaCO Crystals.

Formulation of multifunctional biopolymer-based scaffolds is one of the major focuses in modern tissue engineering and regenerative medicine. Besides proper mechanical/chemical properties, an ideal scaffold should: (i) possess a well-tuned porous internal structure for cell seeding/growth and (ii) host bioactive molecules to be protected against biodegradation and presented to cells when required. Alginate hydrogels were extensively developed to serve as scaffolds, and recent advances in the hydrogel formulation demonstrate their applicability as "ideal" soft scaffolds.

Mucin adsorption on vaterite CaCO microcrystals for the prediction of mucoadhesive properties.

Porous vaterite CaCO crystals are widely used as containers for drug loading and as sacrificial templates to assemble polymer-based nano- and micro-particles at mild conditions. Special attention is paid nowadays to mucosal delivery where the glycoprotein mucin plays a crucial role as a main component of a mucous. In this work mucoadhesive properties of vaterite crystals have been tested by investigation of mucin binding to the crystals as a function of (i) time, (ii) glycoprotein concentration, (iii) adsorption conditions and (iv) degree of mucin desialization.

Internal Structure of Matrix-Type Multilayer Capsules Templated on Porous Vaterite CaCO₃ Crystals as Probed by Staining with a Fluorescence Dye.

Multilayer capsules templated on decomposable vaterite CaCO₃ crystals are widely used as vehicles for drug delivery. The capsule represents typically not a hollow but matrix-like structure due to polymer diffusion into the porous crystals during multilayer deposition. The capsule formation mechanism is not well-studied but its understanding is crucial to tune capsule structure for a proper drug release performance.

Self-Assembled Mucin-Containing Microcarriers via Hard Templating on CaCO₃ Crystals.

Porous vaterite crystals of CaCO₃ are extensively used for the fabrication of self-assembled polymer-based microparticles (capsules, beads, etc.) utilized for drug delivery and controlled release. The nature of the polymer used plays a crucial role and discovery of new perspective biopolymers is essential to assemble microparticles with desired characteristics, such as biocompatibility, drug loading efficiency/capacity, release rate, and stability.

A "Cell-Friendly" Window for the Interaction of Cells with Hyaluronic Acid/Poly-l-Lysine Multilayers.

Polyelectrolyte multilayers assembled from hyaluronic acid (HA) and poly-l-lysine (PLL) are most widely studied showing excellent reservoir characteristics to host molecules of diverse nature; however, thick (HA/PLL) films are often found cell repellent. By a systematic study of the adhesion and proliferation of various cells as a function of bilayer number "n" a correlation with the mechanical and chemical properties of films is developed. The following cell lines have been studied: mouse 3T3 and L929 fibroblasts, human foreskin primary fibroblasts VH-Fib, human embryonic kidney HEK-293, human bone cell line U-2-OS, Chinese hamster ovary CHO-K and mouse embryonic stem cells.

Binding Mechanism of the Model Charged Dye Carboxyfluorescein to Hyaluronan/Polylysine Multilayers.

Biopolymer-based multilayers become more and more attractive due to the vast span of biological application they can be used for, e.g., implant coatings, cell culture supports, scaffolds.