Collagen Nanoparticles in Drug Delivery Systems and Tissue Engineering

The versatile natural polymer, collagen, has gained vast attention in biomedicine. Due to its biocompatibility, biodegradability, weak antigenicity, biomimetics and well-known safety profile, it is widely used as a drug, protein and gene carrier, and as a scaffold matrix in tissue engineering. Nanoparticles develop favorable chemical and physical properties such as increased drug half-life, improved hydrophobic drug solubility and controlled and targeted drug release. Their reduced toxicity, controllable characteristics of scaffolds and stimuli-responsive behavior make them suitable in regenerative medicine and tissue engineering. Collagen associates and absorbs nanoparticles leading to significant impacts on their biological functioning in any biofluid. This review will discuss collagen nanoparticle preparation methods and their applications and developments in drug delivery systems and tissue engineering.

Distinct endocytosis and immune activation of poly(lactic-co-glycolic) acid nanoparticles prepared by single- and double-emulsion evaporation

Background: Poly(lactic-co-glycolic) acid (PLGA) nanoparticles can be prepared by emulsion-solvent-evaporation from o/w and w1/o/w2 emulsions. Aims: To elaborate similarities and differences regarding mechanical, morphological and physicochemical properties, as well as endocytosis and dose-dependent immune responses by primary human leukocytes between nanoparticles prepared by these two methods. Methods: Fluorescently labeled as well as TLR agonist (R848)-loaded PLGA nanoparticles were prepared via both single- and double-emulsion solvent evaporation. Results: Particles prepared by both methods were similar in chemical composition and surface charge but exhibited slight differences in size and morphology. Pronounced differences were found for loading, dissolution and mechanical properties. The particles were differently endocytosed by monocytes and induced qualitatively and quantitatively different immune responses. Conclusions: Variations in nanoparticle preparation can affect particle-derived immunological characteristics.

Natural synthesis of silver nanoparticles from grape fruit juice and estimation of antimicrobial activity

Silver has been known for its antimicrobial activity for a very long time. Formulation of silver particles that range from 1-100nm in size makes it even more potent to induce antimicrobial effect. Green chemistry has started to become more frequent in the field of biochemical research. Silver nanoparticles synthesized from green synthesis method provide a cheap and environmental friendly method of nanoparticle preparation. The aim of the current study is green synthesis of silver nanoparticles using tomato juice as reducing and capping agent and evaluation of its antimicrobial activity. The stability and conformation of SNPs was determined by UV-visible spectroscopy. The antimicrobial activity of synthesized SNPs was determined against E.coli DH5α. Ultraviolet spectroscopic analysis offered peak at 400 nm that indicate the production of SNPs of adequate size. E.coli DH5α showed considerable decrease upon introduction of SNPs to the bacterial inoculum. Upon increasing the concentration of silver nanoparticles an increase in zone of inhibition was recorded. For 70µg/ml of SNPs, the zone of inhibition was 0.5 cm, while 0.6 cm, 0.7 cm and 0.7cm was recorded for 100µg/ml, 150µg/ml and 200µg/ml of SNPs respectively. The efficacy of antimicrobial activity of SNPs derived from tomato juice proves its potential use in pharmaceutical and medicinal industries for synthesis of nanomedicine.

Nanomedicine-based antimicrobial peptide delivery for bacterial infections: recent advances and future prospects

Background Antimicrobial peptides (AMPs) have gained wide interest as viable alternatives to antibiotics owing to their potent antimicrobial effects and the low propensity of resistance development. However, their physicochemical properties (solubility, charge, hydrophobicity/hydrophilicity), stability issues (proteolytic or enzymatic degradation, aggregation, chemical degradation), and toxicities (interactions with blood components or cellular toxicities) limit their therapeutic applications. Area covered Nanomedicine-based therapeutic delivery is an emerging concept. The AMP loaded nanoparticles have been prepared and investigated for their antimicrobial effects. In this review, we will discuss different nanomedicine-based AMP delivery systems including metallic nanoparticles, lipid nanoparticles, polymeric nanoparticles, and their hybrid systems along with their future prospects for potent antimicrobial efficacy. Expert opinion Nanomedicine-based AMP delivery is a recent approach to the treatment of bacterial infections. The advantageous properties of nanoparticles including the enhancement of AMP stability, controlled release, and targetability make them suitable for the augmentation of AMP activity. Modifications in the nanomedicine-based approach are required to overcome the problems of nanoparticle instability, shorter residence time, and toxicity. Future rigorous studies for both the AMP loaded nanoparticle preparation and characterization, and detailed evaluations of their in vitro and in vivo antimicrobial effects and toxicities, are essential.

Synthesis of Densely Immobilized Gold-Assembled Silica Nanostructures

In this study, dense gold-assembled SiO2 nanostructure (SiO2@Au) was successfully developed using the Au seed-mediated growth. First, SiO2 (150 nm) was prepared, modified by amino groups, and incubated by gold nanoparticles (ca. 3 nm Au metal nanoparticles (NPs)) to immobilize Au NPs to SiO2 surface. Then, Au NPs were grown on the prepared SiO2@Au seed by reducing chloroauric acid (HAuCl4) by ascorbic acid (AA) in the presence of polyvinylpyrrolidone (PVP). The presence of bigger (ca. 20 nm) Au NPs on the SiO2 surface was confirmed by transmittance electronic microscopy (TEM) images, color changes to dark blue, and UV-vis spectra broadening in the range of 450 to 750 nm. The SiO2@Au nanostructure showed several advantages compared to the hydrofluoric acid (HF)-treated SiO2@Au, such as easy separation, surface modification stability by 11-mercaptopundecanoic acid (R-COOH), 11-mercapto-1-undecanol (R-OH), and 1-undecanethiol (R-CH3), and a better peroxidase-like catalysis activity for 5,5′-Tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) reaction. The catalytic activity of SiO2@Au was two times better than that of HF-treated SiO2@Au. When SiO2@Au nanostructure was used as a surface enhanced Raman scattering (SERS) substrate, the signal of 4-aminophenol (4-ATP) on the surface of SiO2@Au was also stronger than that of HF-treated SiO2@Au. This study provides a potential method for nanoparticle preparation which can be replaced for Au NPs in further research and development.

Fabrication and Applications of Microfluidic Devices: A Review

Microfluidics is a relatively newly emerged field based on the combined principles of physics, chemistry, biology, fluid dynamics, microelectronics, and material science. Various materials can be processed into miniaturized chips containing channels and chambers in the microscale range. A diverse repertoire of methods can be chosen to manufacture such platforms of desired size, shape, and geometry. Whether they are used alone or in combination with other devices, microfluidic chips can be employed in nanoparticle preparation, drug encapsulation, delivery, and targeting, cell analysis, diagnosis, and cell culture. This paper presents microfluidic technology in terms of the available platform materials and fabrication techniques, also focusing on the biomedical applications of these remarkable devices.

Comparative Study of Anti Microbial Activity of Dose Dependent Silver Nanoparticle Preparation, Iodophor and Chlorhexidine against Extended Spectrum Beta Lactamase Strains

Iodophor, chlorhexidine and silver nanoparticle preparation were tested against Extended spectrum beta lactamase strains (ESBL strains) in this study. This was done in order to compare the antibacterial activities of 5% iodophor, 4% chlorhexidine and silver nanoparticle preparation. A major problem for chemotherapy of bacterial agents in today’s world is the development of multi drug resistance. ESBL is one of the most common problematic multidrug resistant pathogens. Beta lactamase are enzymes which are produced by certain kinds of bacteria. They have the ability to breakdown the active ingredient in certain common antibiotics and thus making them ineffective. Iodophor and chlorhexidine are chemical disinfectants which show antimicrobial activity. Iodine is said to be one of the most lethal agents that enters the cell and inhibits synthesis of proteins. Iodophors are less toxic and they do not irritate the skin when used for disinfection. Chlorhexidine is also a commonly used antiseptic and they are very commonly used as a disinfectant before surgical procedures and for sterilisation procedures. Silver nanoparticle, another component tested against ESBL strain in this study is a biological preparation. Many studies have described the antimicrobial properties of silver and it is proven to be a powerful bactericidal agent as it can effectively cross biological membranes. Although considered to be toxic at high concentrations in human beings, less than 1% concentration of silver nanoparticle preparation is used for controlling bacteria in dental therapies, wounds, burns and catheters.