Standard Sterilization Procedures Research Articles

Endoreduplication changes in five in-vitro-grown crops upon treatment with silver nanoparticles

Silver nanoparticles (AgNPs) are now often utilized in agriculture and horticulture. One of the common applications is to use AgNPs as antimicrobial agents in tissue cultures instead of using standard sterilization procedures. However, in addition to beneficial effects they have also cyto- and genotoxic ones, inducing DNA damage and changing cell cycle dynamics. The aim of this study was to determine the effect of AgNPs at different concentrations (50–100 ppm) on endoreduplication, DNA content, and growth of seedlings of five crops: rapeseed, white mustard, sugar beet, red clover, and alfalfa, cultivated in vitro. Flow cytometry was used to establish genome size and DNA synthesis patterns in the roots, hypocotyls, and leaves of first-leaf-pair seedlings. AgNP-treatment did not influence germination or genome size, but increased root length and endoreduplication intensity. The increases were especially pronounced in species/organs with high polysomaty. We suggest that enhanced endopolyploidization is a defense mechanism against the stress induced by AgNPs causing mitotic division disruption.

Stability of Ti3C2Tx MXene Films and Devices under Clinical Sterilization Processes.

MXenes are being heavily investigated in biomedical research, with applications ranging from regenerative medicine to bioelectronics. To enable the adoption and integration of MXenes into therapeutic platforms and devices, however, their stability under standard sterilization procedures must be established. Here, we present a comprehensive investigation of the electrical, chemical, structural, and mechanical effects of common thermal (autoclave) and chemical (ethylene oxide (EtO) and H2O2 gas plasma) sterilization protocols on both thin-film Ti3C2Tx MXene microelectrodes and mesoscale arrays made from Ti3C2Tx-infused cellulose-elastomer composites. We also evaluate the effectiveness of the sterilization processes in eliminating all pathogens from the Ti3C2Tx films and composites. Post-sterilization analysis revealed that autoclave and EtO did not alter the DC conductivity, electrochemical impedance, surface morphology, or crystallographic structure of Ti3C2Tx and were both effective at eliminating E. coli from both types of Ti3C2Tx-based devices. On the other end, exposure to H2O2 gas plasma sterilization for 45 min induced severe degradation of the structure and properties of Ti3C2Tx films and composites. The stability of the Ti3C2Tx after EtO and autoclave sterilization and the complete removal of pathogens establish the viability of both sterilization processes for Ti3C2Tx-based technologies.

Can Steam Sterilization Affect the Accuracy of Point-of-Care 3D Printed Polyetheretherketone (PEEK) Customized Cranial Implants? An Investigative Analysis.

Polyetheretherketone (PEEK) has become the biomaterial of choice for repairing craniofacial defects over time. Prospects for the point-of-care (POC) fabrication of PEEK customized implants have surfaced thanks to the developments in three-dimensional (3D) printing systems. Consequently, it has become essential to investigate the characteristics of these in-house fabricated implants so that they meet the necessary standards and eventually provide the intended clinical benefits. This study aimed to investigate the effects of the steam sterilization method on the dimensional accuracy of POC 3D-printed PEEK customized cranial implants. The objective was to assess the influence of standard sterilization procedures on material extrusion-based 3D-printed PEEK customized implants with non-destructive material testing. Fifteen PEEK customized cranial implants were fabricated using an in-house material extrusion-based 3D printer. After fabrication, the cranial implants were digitalized with a professional-grade optical scanner before and after sterilization. The dimensional changes for the 3D-printed PEEK cranial implants were analyzed using medically certified 3D image-based engineering software. The material extrusion 3D-printed PEEK customized cranial implants displayed no statistically significant dimensional difference with steam sterilization (p > 0.05). Evaluation of the cranial implants' accuracy revealed that the dimensions were within the clinically acceptable accuracy level with deviations under 1.00 mm. Steam sterilization does not significantly alter the dimensional accuracy of the in-house 3D-printed PEEK customized cranial implants.

Influence of the argon ratio on the structure and properties of thin films prepared using PECVD in TMSAc/Ar mixtures

Capacitively coupled RF glow discharge was used to form novel coatings of SiOxCyHz using varying proportions of trimethylsilyl acetate (TMSAc) monomer and the carrier gas argon. The properties of the TMSAc-based plasma polymers produced depend significantly on the proportion of argon in TMSAc/Ar gaseous mixture, which ranged from 0 % to 75 %. Reaction mixtures containing less than 50 % Ar produced hydrophobic polymers, for which the indentation hardness values were less than 1.5 GPa. Seventy-five percent argon in the reaction mixture yielded a crosslinked carbon-rich organosilicon structure with a hardness of 6 GPa. As many applications require good stability in a liquid environment, the TMSAc-based coatings were immersed in phosphate buffered saline (PBS) for 14 days. Because any material used in a medical application must be resistant to the techniques used for sterilization, the prepared coatings were subjected to a standard sterilization procedure using UVC radiation. A degree of the structural changes induced by both environments corresponded to the argon ratio used for production of thin films. Possible degradation mechanisms were examined and discussed. Using 7.7–21.4 % Ar during the deposition process led to the TMSAc-based plasma polymers exhibiting good resistance to the prolonged immersion in PBS and UVC sterilization.

Detection of Fusarium verticillioides in maize sold at some markets in Ibadan Metropolis, Nigeria

Fusarium is a prominent fungal genus connected with maize in Africa. In this genus, there are two most common species (F. verticillioides and F. proliferatum) that have many toxigenic features and produce fumonisins. Fumonisins are a collection of economically significant mycotoxins that are widely found in maize-based foods and feeds across the globe. This preliminary study was conducted to detect the occurrence of Fusarium verticilliodes in infected maize collected from four main markets in the Ibadan metropolis. A total of ninety-five (95) maize samples were collected from three major commercial markets in Ibadan. Maize seeds were prepared following standard sterilization procedure after which, ten (10) seeds each were then plated on PDA media in triplicates and incubated at 25 oC for six days. Identification of isolates was performed using conventional cultural and morphological characteristics. Results show that the maize samples obtained from Apata market had the highest occurrence of Fusarium verticilliodes with 28.2% while the least occurrence of 22.3% was found in maize samples obtained from Bodija market. Other species of fungi, Aspergillus flavus, Aspergillus niger, and Botryodiplodia Theobroma, were also detected with a negligible count. The study also revealed that there was a significant difference at p = 0.002 in the occurrence of Fusarium verticilliodes between the yellow and white maize seeds studied. These findings call for great concern as it detected that maize and maize-based feed consumed could be infected with Fusarium and fumonisin toxin.

WALANT Hand and Upper Extremity Procedures Performed With Minor Field Sterility Are Associated With Low Infection Rates.

The use of minor field sterility in hand/upper extremity cases has been shown to improve workflow efficiency while maintaining patient safety. As this finding has been limited to specific procedures, we investigated the safety of performing a wide array of hand/upper extremity procedures outside the main operating room using minimal field sterility with Wide-Awake Local Anaesthesia No Tourniquet (WALANT) anaesthesia by evaluating superficial and deep infection rates across a diverse series of cases. This study was a case series conducted between October 2017 and June 2020. Of all, 217 patients underwent hand/upper extremity procedures performed in a minor procedure room via WALANT technique with field sterility. Primary outcome measures include superficial and deep surgical site infections within 14 days post-surgery. Of all, 217 patients were included in this study; 265 consecutive hand/upper extremity operations were performed by a single surgeon, with notable case diversity. The majority of patients (n = 215, 99.1%) did not report or present with signs of infection before or after their operation. We report 0% 14-day and 0.37% 30-day surgical site infection rates for such hand/upper extremity procedures performed in a minor procedure room with field sterility. Hand/upper extremity procedures performed via WALANT technique with field sterility in a minor procedure room are associated with low surgical site infection rates. These rates are comparable to surgical site infection rates for similar surgeries performed in main operating rooms with standard sterilization procedures. Thus, the implementation of this technique may allow for improved workflow efficiency and reduced waste, all while maintaining patient safety.

Electron-beam modification of DLC coatings for biomedical applications

The interest in diamond like carbon (DLC) coatings and their modification for biomedical applications is strongly increasing during the last years. Improvement of surface resistance to scratching and biocompatibility are the main goals of recent developments. Moreover, different capabilities of adjacent areas on surfaces are often required by complex applications.In this study, different deposition methods for diamond-like carbon (DLC) coatings were compared for their suitability in biomedical applications. In addition, DLC coatings modified by non-thermal electron-beams were investigated with regard to their biological interactions. The DLC coatings were deposited using four different methods (plasma-activated chemical vapor deposition, physical vapor deposition by magnetron sputtering, and physical vapor deposition via cathodic arc – both unfiltered and filtered). The different DLC coatings were characterized with regard to their wettability, morphology, roughness, and coating adhesion. The ability of coatings to withstand repeated sterilization cycles was investigated using a specialized test protocol parallel to standard sterilization procedures for medical devices. Biological evaluation was performed using human fibroblasts by assessing metabolic activity and cell counts. Electron-beam modification of the coatings was performed under ambient conditions using a low-energy electron-beam facility (150kV acceleration voltage).All DLC coatings investigated were found to be biocompatible, with the coating deposited by magnetron sputtering showing the best results. In general, electron-beam modification resulted in the hydrophilicity of the different DLC coatings increasing, but no changes in surface morphology or roughness were observed. The cell adhesion to electron-beam-modified DLC coatings was reduced to 30% of the untreated DLC coatings, what can be attributed to changes in the surface chemistry. The long-term stability of the modified DLC coatings was also confirmed. Therefore, electron-beam treatment represents a promising tool for modifying and functionalizing DLC coatings, especially if varying requirements concerning biomedical functionality and cell adhesion are involved.

The influence of triangular silver nanoplates on antimicrobial activity and color of cotton fabrics pretreated with chitosan

The effect of cotton fabric pretreatment with biopolymer chitosan (CHT) on deposition of colloidal triangular silver nanoplates was studied. Also, the influence of deposited silver nanoparticles on color and antimicrobial activity of cotton fabrics was evaluated. Characterization of colloidal silver nanoparticles as well as silver nanoparticles deposited on cotton fabrics was performed using electron microscopy (TEM and FESEM), XRD analysis, atomic absorption spectroscopy, UV–Vis absorption, and reflectance spectroscopy. The cotton fabric turned from white to blue color upon deposition of triangular silver nanoplates. Antimicrobial activity of CHT pretreated cotton fabric impregnated with silver nanoparticles was tested against Gram-negative bacteria Escherichia coli, Gram-positive bacteria Staphylococcus aureus, and fungi Candida albicans. Deposited silver nanoparticles imparted excellent antimicrobial properties to cotton fabric. The standard sterilization procedure of cotton fabric for antimicrobial activity testing resulted in color change of the fabric from blue to yellow. This color change is most likely consequence of transformation of triangular silver nanoplates into nanodiscs and/or their agglomeration into spheroids.

Assembly of Standardized Test Specimen for Microbial Quantification of Plasma Sterilization Processes of Fine PTFE Tubes as Used in Thermo Sensitive Medical Devices Like Flexible Endoscopes

AbstractFine PTFE tubes are used in high‐end and high cost devices like flexible Endoscopes where no standard sterilization procedure like autoclaving applies due to material properties. The study of innovative decontamination processes like plasma sterilization request appropriate analysis methods in order to verify the process functionality. In a related research project the IGB‐cycle‐method for contamination and recovery of indicator organisms like Bacillus atrophaeus spores was developed. It was possible to proof the IGB‐cycle‐method to be reproducible and reliable using round robin tests between three laboratories that compared their results in reference to a relevant level of contamination and recovery. Of a relevant contamination more than 7 log10 steps of cfu/specimen could be recovered from the tube surface. magnified image

Scanning Electron Microscopy study of the standard sterilization procedure applied to dental instruments

Scanning Electron Microscopy study of the standard sterilization procedure applied to dental instruments

A micro-perfusion chamber for single-cell fluorescence measurements

A versatile closed micro-perfusion chamber designed for single-cell fluorescence measurements under maximum microscopic magnification is described. Glass coverslips with adherent cells can be attached to the top or bottom of the chamber, depending on whether an inverted or an upright microscope is used. Eight conical holes drilled in the side of the chamber serve for the insertion of plugs with attachments for perfusion, rapid injection of small amounts of reagents, temperature measurements or for heating the interior of the chamber. Materials used in the construction of the chamber are non-toxic and resistant to standard sterilization procedures. Perfusion and temperature properties of the chamber are described. Single cell fluorescence measurements are presented in human monocyte-derived macrophages in which NAD(P)H and intracellular calcium are measured.