Assembly of Turing-Like Patterns from Multi-Shaped Starch Nanoparticles on PDMS Films for Applications as Anti-Biofilm Coatings

This study aimed to investigate the effect of Deoxyribonuclease I (DNase I) coating on initial adhesion and biofilm formation of peri-implant bacteria. Titanium (Ti), Ti-polydopamine (Ti-PDOP), Ti-PDOP-DNase I and Ti-PDOP-inactivated DNase I samples were studied. The FE-SEM, EDS and XPS were used to confirm that DNase I was coated onto Ti. The initial adhesion and biofilm formation of Aggregatibacter actinomycetemcomitans (A.a) and Fusobacterium nucleatum (F.n) were observed by CLSM. The osteogenic induction of Ti-PDOP-DNase I on MC3T3-E1 cells was investigated by ALP activity and RT-PCR. The adhesion clearance rate of viable bacteria on the surfaces of Ti-PDOP-DNase I was 91.95% for A.a, and 96.37% for F.n, and the 24 h biofilm formation of the bacteria was significantly inhibited. In addition, on DNase I coating, the mRNA level of osteogenic marker genes (alp, opn, bsp, sp7) and the activity of ALP were both up-regulated. Therefore, DNase I coating could be an alternative approach for preventing implant-related infection.

Porous materials have become a burgeoning research interest in materials science because of their intrinsic porous characteristics, versatile chemical compositions, and abundant functionalities. Re...

Effects of DNase I coating of titanium on bacteria adhesion and biofilm formation

The accumulation of biofilms can potentially be very costly in terms of damage to mechanical systems and health impact on the human body. Space travel, especially long-term space travel, compounds the complications that arise from the accumulation of biofilms because of the lack of access to resources. This study investigates the ability of polyampholyte copolymer thin films to reduce bacteria adhesion in microgravity. Copolymer systems of [2-(acryloyloxy)ethyl] trimethylammonium chloride (TMA) and 2-carboxyethyl acrylate (CAA) and TMA and 3-sulfopropyl methacrylate potassium salt (SA) have previously shown resistance to bacteria adhesion under gravity-impacted conditions. However, their performance under microgravity conditions has never been evaluated. A self-contained payload was designed around multiple constraints to evaluate the ability of the TMA/CAA and TMA/SA thin film coatings to reduce the adhesion and biofilm formation of Staphylococcus epidermidis on aluminum test coupons in microgravity in an experiment conducted onboard the International Space Station (ISS). An Earth-based, gravity-impacted study was completed in parallel with the ISS experiment. The samples were then analyzed on the macroscale using photography and the microscale using confocal microscopy imaging to determine biofilm formation and bacteria attachment, respectively. The percentage of each sample covered by bacteria and/or biofilm was characterized and compared amongst the coating types and gravity exposure conditions. The TMA/SA coatings showed the lowest levels of bacteria adhesion and biofilm formation overall. The TMA/CAA coatings showed the largest reduction in bacteria adhesion and biofilm formation when comparing adhesion between the microgravity- and gravity-impacted samples. Therefore, both the copolymers demonstrate promise for bacteria-resistant coatings in microgravity.

Evaluation and characterization of starch nanoparticles for adsorption of urea from dialysates

BackgroundStarch is a carbohydrate polymer, made up of multiple glucose units, connected through glycosidic bonds. Starch nanoparticles (StNPs) are characterized as particles that possess at least one dimension measuring less than 1000 nm, while still being larger than a single molecule, and they have several uses in diverse technological fields. Various studies indicate that synthesizing StNPs through physical and chemical techniques is expensive, requires a lot of energy, and may harm human health and the environment. In contrast, the enzymatic synthesis of StNPs exerts milder impacts on the final products, rendering them more eco-friendly, safe, and healthier. So, amylases can produce StNPs with enhanced solubility, gelation, and viscosity characteristics by hydrolyzing soluble starches.ResultsThis study explores the production of starch nanoparticles (StNPs) by α-amylase enzyme in situ from a newly isolated bacterial strain, which was biochemically described, genetically identified, and deposited into the database of GenBank under the designation Bacillus subtilis strain-MA6 (accession number: ON840082). The production medium was adjusted by employing statistical optimization of several parameters using the Plackett-Burman design (P-BD) and Box-Behnken design (B-BD) of the response surface methodology (RSM). Optimization of medium parameters using P-BD and B-BD models caused a 14.5-fold increase in α-amylase production. The StNPs were synthesized from bulk starch using three different α-amylase activities. Based on the B-BD results, trial 5 (B-BD/T5), trial 7 (B-BD/T7), and trial 13 (B-BD/T13) were selected for the StNPs characterization using Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), and high-resolution transmission electron microscopy (HR-TEM) analysis. Trial 13 represented the highest α-amylase activity and observed high stability with an average zeta potential of about − 15.1 ± 3.2 mV. Moreover, HR-TEM showed the StNPs as spheres with an average size of about 43 nm.ConclusionStNPs were synthesized from bulk starch using the B. subtilis strain-MA6 α-amylase enzyme. The concentration of α-amylase plays a role in converting bulk starch to nanosized particles, which affects the stability of the produced nanoparticles and their size. This observation offered an optimistic technique to produce StNPs via a green and eco-friendly process.Graphical abstract

Green sago starch nanoparticles as reinforcing material for green composites

This work investigated the potential of curcumin (CCM) and (-)-epigallocatechin gallate (EGCG) to inhibit N-acyl homoserine lactone (AHL)-mediated biofilm formation in gramnegative bacteria from membrane bioreactor (MBR) activated sludge. The minimum inhibitory concentrations (MICs) of CCM alone against all the tested bacteria were 200-350 μg/ml, whereas those for EGCG were 300-600 μg/ml. Biofilm formation at one-half MICs indicated that CCM and EGCG alone respectively inhibited 52-68% and 59-78% of biofilm formation among all the tested bacteria. However, their combination resulted in 95-99% of biofilm reduction. Quorum sensing inhibition (QSI) assay with known biosensor strains demonstrated that CCM inhibited the expression of C4 and C6 homoserine lactones (HSLs)-mediated phenotypes, whereas EGCG inhibited C4, C6, and C10 HSLs-based phenotypes. The Center for Disease Control biofilm reactor containing a multispecies culture of nine bacteria with onehalf MIC of CCM (150 μg/ml) and EGCG (275 μg/ml) showed 17 and 14 μg/cm(2) of extracellular polymeric substances (EPS) on polyvinylidene fluoride membrane surface, whereas their combination (100 μg/ml of each) exhibited much lower EPS content (3 μg/cm(2)). Confocal laser scanning microscopy observations also illustrated that the combination of compounds tremendously reduced the biofilm thickness. The combined effect of CCM with EGCG clearly reveals for the first time the enhanced inhibition of AHL-mediated biofilm formation in bacteria from activated sludge. Thus, such combined natural QSI approach could be used for the inhibition of membrane biofouling in MBRs treating wastewaters.

Brazilian green propolis-loaded starch nanoparticles: Influence of extraction conditions on bioactivity and kinetic stability under thermal and pH stress.

Eco-friendly and superhydrophobic nano-starch based coatings for self-cleaning application and oil-water separation

Extracellular DNA (eDNA) plays a significant role in bacterial biofilm formation and aggregation. Here, for the first time, we present a physico-chemical analysis of the DNA-mediated aggregation for three bacterial strains (Streptococcus mutansLT11, Pseudomonas aeruginosaPAO1 and Staphylococcus epidermidis 1457). Adsorption of DNA on bacterial cell surfaces increased with increasing DNA concentration, reaching a level of around 4–6 × 10−9 μg DNA per bacterium, concurrent with maximal bacterial aggregation. Further increase in DNA adsorption caused a decrease in aggregation. Water contact angles on bacterial lawns increased upon adsorption of DNA and were highest at the DNA concentration, where maximal bacterial aggregation of the three strains occurred. Bacterial ζ-potentials became more negative with increasing DNA adsorption and were the most negative at the DNA concentrations yielding maximal bacterial aggregation. Extended DLVO-calculations of bacterial aggregation energies for the three bacterial strains indicated that DNA-mediated aggregation was caused by an interplay of attractive Lifshitz–van der Waals and acid–base interactions. For the streptococcal strain, AFM retract force–distance curves indicated stronger adhesion forces in the presence of naturally occurring eDNA than in its absence. Subsequent Poisson analysis of retract force–distance curves confirmed that acid–base interactions dictate DNA-mediated bacterial aggregation. The distance over which adhesion forces could be detected in the presence of eDNA was approximately 200 nm larger than in its absence, suggesting eDNA is present as loops with a length of about 400 nm, corresponding with 1.2 kb of DNA in a fully extended state.

Rheology, stability, antioxidant properties, and curcumin release of oil-in-water Pickering emulsions stabilized by rice starch nanoparticles

Fabrication of non-woven composite membrane by chitosan coating for resisting the adsorption of proteins and the adhesion of bacteria

Recent advances in anti-adhesion mechanism of natural antimicrobial agents on fresh produce

Quorum sensing molecules regulate epithelial cytokine response and biofilm-related virulence of three Prevotella species