Biomarkers and diagnostic tools for detection of Helicobacter pylori

Helicobacter pylori is responsible for worldwide chronic bacterial infection in humans affecting approximately half of the world’s population. H. pylori is associated with significant morbidity and mortality including gastric cancer. The infection has both direct and indirect impacts on economic and overall well-being of patients; hence, there is a great need for diagnostic markers that could be used in the development of diagnostic kits. Here, we briefly review general aspects of H. pylori infection and the diagnostic biomarkers used in laboratory tests today with a focus on the potential role of microfluidic systems in future immunodiagnosis platforms

Biomedical and microbiological applications of bio-based porous materials: a review

Extensive employment of biomaterials in the areas of biomedical and microbiological applications is considered to be of prime importance. As expected, oil based polymer materials were gradually replaced by natural or synthetic biopolymers due to their well-known intrinsic characteristics such as biodegradability, non-toxicity and biocompatibility. Literature on this subject was found to be expanding, especially in the areas of biomedical and microbiological applications. Introduction of porosity into a biomaterial broadens the scope of applications. In addition, increased porosity can have a beneficial effect for the applications which exploit their exceptional ability of loading, retaining and releasing of fluids. Different applications require a unique set of pore characteristics in the biopolymer matrix. Various pore morphologies have different characteristics and contribute different performances to the biopolymer matrix. Fabrication methods for bio-based porous materials more related to the choice of material. By choosing the appropriate combination of fabrication technique and biomaterial employment, one can obtain tunable pore characteristic to fulfill the requirements of desired application. In our previous review, we described the literature related to biopolymers and fabrication techniques of porous materials. This paper we will focus on the biomedical and microbiological applications of bio-based porous materials

Antimicrobial Peptides: Multifunctional Drugs for Different Applications

Antimicrobial peptides (APs) are an important part of the innate immune system in epithelial and non-epithelial surfaces. So far, many different antimicrobial peptides from various families have been discovered in non-vertebrates and vertebrates. They are characterized by antibiotic, antifungal and antiviral activities against a variety of microorganisms. In addition to their role as endogenous antimicrobials, APs participate in multiple aspects of immunity. They are involved in septic and non-septic inflammation, wound repair, angiogenesis, regulation of the adaptive immune system and in maintaining homeostasis. Due to those characteristics AP could play an important role in many practical applications. Limited therapeutic efficiency of current antimicrobial agents and the emerging resistance of pathogens require alternate antimicrobial drugs. The purpose of this review is to highlight recent literature on functions and mechanisms of APs. It also shows their current practical applications as peptide therapeutics and bioactive polymers and discusses the possibilities of future clinical developments

Hybrid Microscopy: Enabling Inexpensive High-Performance Imaging through Combined Physical and Optical Magnifications

To date, much effort has been expended on making high-performance microscopes through better instrumentation. Recently, it was discovered that physical magnification of specimens was possible, through a technique called expansion microscopy (ExM), raising the question of whether physical magnification, coupled to inexpensive optics, could together match the performance of high-end optical equipment, at a tiny fraction of the price. Here we show that such “hybrid microscopy” methods—combining physical and optical magnifications—can indeed achieve high performance at low cost. By physically magnifying objects, then imaging them on cheap miniature fluorescence microscopes (“mini-microscopes”), it is possible to image at a resolution comparable to that previously attainable only with benchtop microscopes that present costs orders of magnitude higher. We believe that this unprecedented hybrid technology that combines expansion microscopy, based on physical magnification, and mini-microscopy, relying on conventional optics—a process we refer to as Expansion Mini-Microscopy (ExMM)—is a highly promising alternative method for performing cost-effective, high-resolution imaging of biological samples. With further advancement of the technology, we believe that ExMM will find widespread applications for high-resolution imaging particularly in research and healthcare scenarios in undeveloped countries or remote places

Bioinspired bactericidal surfaces with polymer nanocone arrays

Infections resulting from bacterial biofilm formation on the surface of medical devices are challenging to treat and can cause significant patient morbidity. Recently, it has become apparent that regulation of surface nanotopography can render surfaces bactericidal. In this study, poly(ethylene terephthalate) nanocone arrays are generated through a polystyrene nanosphere-mask colloidal lithographic process. It is shown that modification of the mask diameter leads to a direct modification of centre-to-centre spacing between nanocones. By altering the oxygen plasma etching time it is possible to modify the height, tip width and base diameter of the individual nanocone features. The bactericidal activity of the nanocone arrays was investigated against Escherichia coli and Klebsiella pneumoniae. It is shown that surfaces with the most densely populated nanocone arrays (center-to-center spacing of 200 nm), higher aspect ratios (>3) and tip widths <20 nm kill the highest percentage of bacteria (∼30%)

Local delivery of antimicrobial peptides from titanium surface for the prevention of implant-associated infections

Titanium (Ti) is a key biomedical material extensively used in orthopaedic implants. Prevention of implant-associated infections has been one of the main challenges in orthopaedic surgery. This challenge is further complicated by the concern over the development of antibiotic resistance as a result of using traditional antibiotics for infection prophylaxis. One of the promising alternatives is the family of antimicrobial peptides (AMPs). The present dissertation develops progressive approaches that enable the loading and local delivery of a unique group of cationic antimicrobial peptides through titanium implant surfaces. In the first technique, a thin layer of micro-porous calcium phosphate (CaP) coating was processed by electrolytic deposition onto the surface of titanium as the drug carrier. The AMP-loaded CaP coating was not cytotoxic for MG-63 osteoblast-like cells, and the implants showed high antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria with 10⁶-fold reductions of both bacterial strains within 30 min and ∼92% and ∼77% inhibition of luminescence at 4 h and 24 h, respectively. Second study investigated the in vitro AMP release, antimicrobial performance, and cytotoxicity of a modified Tet213 (HHC36), as well as the in vivo bone growth of AMP loaded into calcium phosphate coated Ti implants in a rabbit model. Burst release during the first few hours followed by a slow and steady release for 7 days was observed. In vivo bone growth study showed that loading of AMP did not impair bone growth onto the implants. In the last study multilayer thin films of titania nanotubes (NT) and CaP coatings were formulated with AMP and were topped with a thin phospholipid film similar to cell membrane. The films were shown to be non-cytotoxic, hydrophilic, with the potential of tuning loading and release kinetics of AMP. The best model describing the AMP release was first-order model. The first two approaches demonstrated a promising method for an early stage peri-implant infection treatment. The last study proposed a technique to improve the kinetics of AMP release and total loaded AMP quantity, and to increase the Ti interfacial strength while maintain the osteconductivity by applying CaP coating.Applied Science, Faculty ofGraduat