A system approach to improving guideline-directed therapy for cardio-renal-metabolic conditions: The "beyond diabetes" initiative.

Objective: Despite demonstrating improvements in cardiovascular disease, kidney disease, and survival outcomes, guideline-directed antihyperglycemic medications such as sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like-peptide-1 receptor agonists (GLP1-RA), are underutilized. Many obstacles constrain their use including lack of systematic provider and patient education, concern for medication side effects, and patient affordability. Methods: We designed a multimodality, systems-based approach to address these challenges with the goal of increasing medication utilization across the largest healthcare system in New York State. This multispecialty collaborative included provider and patient education, an electronic health record-enabled platform to identify eligible patients, and access to pharmacists for medication guidance and addressing insurance coverage barriers. Surveys were administered following grand rounds lectures and knowledge-based questionnaires were given before and after case-based sessions for housestaff, with results analyzed using a two-sided Student's t-test. Rates of first prescriptions of SGLT2i/GLP1-RA in combined and individual analyses were compared between the pre- and post-education periods (6 months prior to 3/31/2021 and 6 months post 8/19/2021), and the change in prescriptions per 100 eligible-visits was assessed using the incidence density approach. Results: Among grand rounds participants, 69.3% of respondents said they would make changes to their clinical practice. Knowledge increased by 14.7% (p-value <0.001) among housestaff following case-based sessions. An increase in SGLT2i/GLP1-RA prescribing was noted for eligible patients among internal medicine, cardiology, nephrology, and endocrinology providers, from 11.9 per 100 eligible visits in the pre-education period to 14.8 in the post-education period (absolute increase 2.9 [24.4%], incidence risk ratio 1.24 [95% CI 1.18-1.31]; p-value <0.001). Increases in prescribing rates were also seen among individual medical specialties. Conclusions: Our "Beyond Diabetes" initiative showed an improvement in provider knowledge-base and was associated with a modest, but statistically significant increase in the use of SGLT2i and GLP1-RA throughout our healthcare system.

Outcomes of Escalating Immunosuppressive Treatments for Recalcitrant Noninfectious Posterior Scleritis.

INTRODUCTION: This article aimed to summarize the outcomes of escalating immunosuppressive treatments for patients with recalcitrant noninfectious posterior scleritis (PS). METHODS: Clinical records of 16 patients diagnosed with recalcitrant noninfectious PS in the Ocular Immunity and Uveitis Department of Zhongshan Ophthalmic Center from September 2016 to December 2021 were reviewed. Patients were treated with escalating immunosuppressive regimen including corticosteroid, immunosuppressants (IMTs), and adalimumab (ADA). Demographic characteristics and clinical findings at each visit were recorded. The doses of prednisone were analyzed. Main outcomes were corticosteroid-sparing effects, control of inflammation, visual acuity, and safety profile. RESULTS: Ocular pain was the most common finding (100%), followed by the T sign on the B scan (93.8%) and associated anterior scleritis (75.0%). The average initial dose of prednisone was 25.0 mg/day, and tapered to 11.3 and 5.0 mg/day at month 1 and 3, respectively, with statistical significance (p < 0.05). The median overall periods of prednisone tapering to 10, 5, and 0 mg/day were 1.0, 3.0, and 3.0 months, respectively. There were 93.8% of patients receiving prednisone ≤ 10 mg/day and 68.8% of patients off prednisone at last visit. There were 80% of patients treated with IMT and ADA off prednisone at last visit, reaching the highest percentage compared with others. A best-corrected visual acuity of 1.0 or better at last visit was achieved in 10 eyes (62.5%). The escalating treatments showed good safety profile. CONCLUSION: Patients of recalcitrant noninfectious PS benefited from escalating immunosuppressive treatments with favorable visual outcome, in which methotrexate, ciclosporin, and ADA were preferred with good safety.

Doxycycline vs Placebo at 12 Weeks in Patients With Mild Thyroid-Associated Ophthalmopathy: A Randomized Clinical Trial.

Importance: Mild thyroid-associated ophthalmopathy (TAO) negatively impacts quality of life, yet no clinical guidelines for its treatment are available. Existing evidence supports the use of doxycycline in treating mild TAO. Objective: To evaluate the short-term (12 weeks) efficacy of doxycycline in treating mild TAO. Design, Setting, and Participants: In this placebo-controlled multicenter randomized double-masked trial, 148 patients were assessed for eligibility. After exclusions (patients who were pregnant or lactating, had an allergy to tetracyclines, or had uncontrolled systematic diseases), 100 patients with mild TAO (orbital soft tissue affected mildly) at 5 centers in China were enrolled from July 2013 to December 2019 and monitored for 12 weeks. Interventions: Participants were randomly assigned 1:1 to receive doxycycline (50 mg) or placebo once daily for 12 weeks. Main Outcomes and Measures: The primary outcome was the rate of improvement at 12 weeks compared with baseline assessed by a composite indicator of eyelid aperture (reduction ≥2 mm), proptosis (reduction ≥2 mm), ocular motility (increase ≥8°), and Graves ophthalmopathy-specific quality-of-life (GO-QOL) scale score (increase ≥6 points). Adverse events were recorded. Results: A total of 50 participants were assigned to doxycycline and 50 to placebo. The mean (SD) age was 36.7 (9.1) years; 75 participants (75.0%) were female and 100 (100.0%) were Asian. Medication compliance was checked during participant interviews and by counting excess tablets. At week 12, the improvement rate was 38.0% (19 of 50) in the doxycycline group and 16.0% (8 of 50) in the placebo group (difference, 22.0%; 95% CI, 5.0-39.0; P = .01) in the intention-to-treat population. The per-protocol sensitivity analysis showed similar results (39.6% [19 of 48] vs 16.0% [8 of 50]; difference, 23.6%; 95% CI, 6.4-40.8; P = .009). No adverse events other than 1 case of mild gastric acid regurgitation was recorded in either group. Conclusions and Relevance: The results of this study indicate that oral doxycycline, 50 mg daily, resulted in greater improvement of TAO-related symptoms at 12 weeks compared with placebo in patients with mild TAO. These findings support the consideration of doxycycline for mild TAO but should be tempered by recognizing the relatively short follow-up and the size of the cohort. Trial Registration: ClinicalTrials.gov Identifier: NCT02203682.

Self-assembly of peptide nanofibers with chirality-encoded antimicrobial activity.

The nanostructured antimicrobial agents, self-assembled by the antimicrobial peptides (AMPs), represent an intriguing platform for the treatment of pathogens. Although the structural characteristics significantly influence antimicrobial functionality, the role of chirality is usually ignored and still unclear. Herein, two homochiral AMPs (all L- or all D-amino acids), including C16-LV4LR4 (LL) and C16-DV4DR4 (DD), and a heterochiral AMP with alternating D-/L-amino acids, C16-DV4LR4 (DL), were self-assembled into left-handed, right-handed, and right-handed helical nanofibers, respectively. The valine configuration determined the supramolecular chirality of the nanofibers. However, the DL molecules exhibited a highly aggregated propensity to form more stable helical nanofibers with a lower degree of twist and a larger helical pitch. This characteristic resulted in the optimal antimicrobial activity of the DL nanofibers against both Gram-negative and Gram-positive bacteria. Furthermore, the membrane permeability assay confirmed the higher activity for damaging the cell membrane by the DL nanofibers. These results demonstrated the significance of molecular chirality in directing the self-assembly of the amphiphilic peptides, eventually affecting their antimicrobial activity. This study opens up the possibility to fabricate promising nanostructured antimicrobial materials by controlling the chirality and structure of the materials.

In situ regulation of bacterial cellulose networks by starch from different sources or amylose/amylopectin content during fermentation.

Bacterial cellulose (BC) is a promising biopolymer, but its three-dimensional structure needs to be controllable to be used in multiple fields. BC has some advantages over other types of cellulose, not only in terms of purity and properties but also in terms of modification (in situ modification) during the synthesis process. Here, starches from different sources or with amylose/amylopectin content were added to the growth medium to regulate the structural properties of BC in-situ. The obtained BC membranes were further modified by superhydrophobic treatment for oil-water separation. Starches alter the viscosity of the medium, thus affecting bacterial motility and cellulose synthesis, and adhere to the microfibers, limiting their further polymerization and ultimately altering the membrane porosity, pore size, and mechanical properties perpendicular to the BC fibril layer direction. The average pore diameter of the BC/PS membrane increased by 1.94 times compared to the initial BC membrane. The chemically modified BC/PS membrane exhibited super-hydrophobicity (water contact angle 167°), high oil-water separation flux (dichloromethane, 23,205 Lm-2 h-1 MPa-1), high separation efficiency (>97%). The study provides a foundation for developing methods to regulate the network structure of BC and broaden its application.

The production of bacterial cellulose in Gluconacetobacter xylinus regulated by luxR overexpression of quorum sensing system.

Quorum sensing is a mechanism that facilitates cell-to-cell communication. Through signal molecular density for signal recognition, which leads to the regulation of some physiological and biochemical functions. Gluconacetobacter xylinus CGMCC 2955, which produces bacterial cellulose (BC), synthesizes the LuxR protein belonging to the LuxI/LuxR type QS system. Here, a luxR overexpression vector was transformed into G. xylinus CGMCC 2955. The overexpression of luxR increased the yield of BC by 15.6% after 16 days static culture and reduced the cell density by 15.5% after 120-h-agitated culture. The glucose was used up by G. xylinus-pMV24-luxR at 72-h-agitated fermentation, which 12 h earlier than the wild-type (WT). The total N-acylhomoserine lactones (AHL) content of the luxR-overexpressing strain and the WT strain attained 1367.9 ± 57.86 mg/L and 842.9 ± 54.22 mg/L, respectively. The C12-HSL and C14-HSL contents of G. xylinus-pMV24-luxR were 202 ± 21.66 mg/L and 409.6 ± 0.91 mg/L, which were significantly lower than that of WT. In contrast, C6-HSL showed opposite results. The difference of AHL content proved that overexpression of luxR improved the binding of AHL and showed preference for some specific AHL. The metabolic results demonstrated that upon glucose exhaustion, the consumption of gluconic acid was promoted by luxR overexpression, and the content of D- ( +)-trehalose, an antiretrograde metabolite, increased significantly. KEY POINTS: • The overexpression of luxR increased the yield of bacterial cellulose • The content of signal molecules was significantly different • Differential metabolites were involved in multiple metabolic pathways.

Preparation and characterization of antibacterial bacterial cellulose/chitosan hydrogels impregnated with silver sulfadiazine.

Hydrogels with pH sensitivity and stable mechanical and antibacterial properties have many desirable qualities and broad applications. A hydrogel based on bacterial cellulose and chitosan, impregnated with silver sulfadiazine (<1% w/w), was prepared using glutaraldehyde as the crosslinking agent. The presence of SSd was confirmed by Fourier transform infrared spectroscopy. Micropore size, swelling ratio, pH- sensitivity, and gram positive and negative antibacterial properties were studied by disk diffusion and colony forming unit. X-ray diffraction confirmed the presence of amorphous and crystalline regions in the hydrogel matrix following addition of SSd. The elemental composition, morphology, and mechanical properties of the hydrogels were characterized. Incorporation of SSd into bacterial cellulose-chitosan hydrogels significantly improved their mechanical and antibacterial properties. The antibacterial activity against E. coli and S. aureus was evaluated and SSd-BC/Ch hydrogels are more toxic to S. aureus than to E. coli. We use FESEM to observe bacterial morphology before and after exposure to SSd-BC/Ch hydrogels. The BacLight LIVE/DEAD membrane permeability kit is used to evaluate the membrane permeability of bacteria. These antibacterial hydrogels have many promising applications in food packaging, tissue engineering, drug delivery, clinical, biotechnological, and biomedical fields.

Sustainable, superhydrophobic membranes based on bacterial cellulose for gravity-driven oil/water separation.

Bacterial cellulose (BC) is a substrate material with high purity and robust mechanical strength, but due to its small pore size and relatively expensive price, it is restricted as an oil-/water separation membrane. In this study, cheaper plant cellulose needle-leaf bleached kraft pulp (NBKP) was added to BC to increase the pore size of the composite membrane, and a superhydrophobic/superoleophilic membrane was prepared for oil-/water separation. The modified membrane surface displayed a petal-like micro-structure and a water contact angle (WCA) of 162.3°, while the oil contact angle was decreased to 0°. What's more, the membrane exhibited excellent oil-/water separation under gravity, recyclability, and a separation efficiency (>95 %), and it was both pH and salt resistant. The membrane also remained durably hydrophobic after 10 separation cycles. And the separation methodology is expected to be highly energy-efficient.

[Expression of Adenovirus-mediated Human Clotting Factor IX Gene in Mouse Adipose-derived Stem Cells].

OBJECTIVE: To investigate the adenovirus-mediated expression of human clotting factor IX (hFIX) gene in mouse adipose-derived stem cells(ADSC). METHODS: The mouse ADSC were isolated and cultured in vitro, the morphology of cells was observed and its growth viability was detected by using CCK-8. Cell surface markers CD29,CD90,CD45 were identified by flow cytometry, and its diferentiation ability was identified by adipogenic and osteogenic induction. Morphological changes was observed and the growth curve should be drawn after transfecting ADSC with adenovirus containing hFIX gene. The expression of hFIX gene was detected by RT-PCR. The expression of hFIX protein in ADSC or in culture supernatant was detected by Western blot. hFIX protein in the supernatant was measured by ELISA, and the clotting factor activity of hFIX in culture supernatant was measured by one-stage method. RESULTS: The in vitro cultured mouse ADSC displayed microspherical shape and strong refractive property. Anchoring growth was lasted for 4-6 hours after planting into culture flask. After cultured for 72 hours, the cells showed long spindle-shaped fibrous and swirling arrangement. The overall growth trend of the third generation ADSC cultured in vitro was S-shaped. The formation of lipid droplets could be observed in the induced cells with Oil red O staining by inverted microscope. After alizarin red staining, the orange-red calcified bone nodes were observed in the induced cells under inverted phase contrast microscope. CD29 (99.91%) and CD90 (99.02%) highly expressed in the third generation of ADSC, but CD45 (0.94%) almost not expressed. RT-PCR showed the hFIX gene could expressed in mouse ADSC. Western blot showed that hFIX protein expressed in both ADSC and culture supernatant. FIX:Ag in cell supernatant was 21.33±3.93 ng/(106 cells.24 h) on the first day, 12.63±0.86 ng/(106 cells.24 h) on the third day and 12.63±2.36 ng/(106 cells.24 h) on the ninth day. FIX:C in culture supernatant was 8.5%. CONCLUSION: Adenovirus-carried hFIX gene can effectively transfect ADSC. ADSC modified by hFIX gene can secrete hFIX protein with coagulation activity.

A Lambda Red and FLP/FRT-Mediated Site-Specific Recombination System in Komagataeibacter xylinus and Its Application to Enhance the Productivity of Bacterial Cellulose.

Komagataeibacter xylinus has received increasing attention as an important microorganism for the conversion of several carbon sources to bacterial cellulose (BC). However, BC productivity has been impeded by the lack of efficient genetic engineering techniques. In this study, a lambda Red and FLP/FRT-mediated site-specific recombination system was successfully established in Komagataeibacter xylinus. Using this system, the membrane bound gene gcd, a gene that encodes glucose dehydrogenase, was knocked out to reduce the modification of glucose to gluconic acid. The engineered strain could not produce any gluconic acid and presented a decreased bacterial cellulose (BC) production due to its restricted glucose utilization. To address this problem, the gene of glucose facilitator protein (glf; ZMO0366) was introduced into the knockout strain coupled with the overexpression of the endogenous glucokinase gene (glk). The BC yield of the resultant strain increased by 63.63-173.68%, thus reducing the production cost.

Application of double circular suturing technique (DCST) in repair of giant incision hernias.

BACKGROUND: Our study aims to explore the feasibility and safety of a double circular suturing technique (DCST) in the repair of giant incision hernias. METHODS: The clinical data of 221 patients (95 men and 126 women; the average age was 61.6 years) receiving DCST in the repair of giant incision hernia between January 2010 and December 2018 was analyzed retrospectively. One hundred and five primary and 16 recurrent patients underwent herniorrhaphy with anti-adhesion underlay mesh repair using DCST. RESULTS: All the 221 operations were performed successfully. The average preparation time before the operation and hospital stays were 3.7 days (range, 1-6 days) and 7.5 days (range, 2-16 days), respectively. The average diameter of the hernia ring defect observed intraoperatively was 16.4 cm (range, 12-22 cm). The average time of operation was 83.6 min (range, 43-195 min). There were 2 cases of intestinal fistula, 4 cases of wound infection, 2 cases of mesh infection, 7 cases of serum tumescence, 3 cases of pulmonary infection, and 2 cases of wound dehiscence occurred. One hundred and ninety-five patients were followed up for 6.7 years (range, 0.8-9.5 years) postoperatively. Of them, 9 patients recurred; 14 patients had chronic pain whose visual analog scale (VAS) was 2-4 cm (average 2.7 cm). CONCLUSIONS: With limited preparation time before operations, few postoperative complications, and recurrence rate, DCST in the repair of giant incision hernia is safe and possible clinically.

[Adenovirus-mediated Expression of B-domain-Deleted Human Coagulation Factor â § in ADSC of SD Rats].

OBJECTIVE: To transinfect SD adipose tissue-derived stem cell (ADSC) in vitro with a recombinant adenoviral vector containing human B-domain-deleted FVIII (BDDhFⅧ), so as to lay the foundation for the treatment of hemophilia A by using ADSC combined with BDDhFⅧ gene. METHODS: ADSCs were isolated from the inguinal adipose tissue of SD rats and passed to third passage for identification. Third passage ADSCs were transfected in vitro with recombinant adenovirus vector Ad-BDDhFⅧ-GFP. The experiments were divided into Ad-BDDhFⅧ-GFP-transfected ADSCs group (A), Ad-GFP-transfected ADSC group (B), and untransfected ADSC group (C). CCK-8 method was used to detect the proliferation of transfected cells in three groups, and the expression level of hFⅧ antigen in cell supernatant was detected by ELISA. RT-PCR and Western blot respectively were used to detect the mRNA and protein expression of BDDhFⅧ in the three groups after transfection. RESULTS: The growth curve of third passage cells isolated and cultured showed an inverted "S" shap; the flow cytometry detection showed the positive expression of CD29, CD90, CD44, and the negative expression of CD45 in third passage cells. After the adipogenic and osteogenic induction, the cells could transformed to adipogenic and osteogenic directions. CCK-8 detection showed that the proliferation of cells in 3 groups not was influenced. ELISA showed that the expression of hFⅧAg in group A was significantly higher than that in group B and C (P＜0.05). RT-PCR showed that compared with group A, there was no target band in B and C groups, and BDDhFⅧ gene was not expressed. The results in group A were consistent with the length of amplified fragments, and BDDhFⅧ target gene was expressed. Western blot analysis showed that the expression of hFⅧ protein in group A was significantly higher than that in group B and C. (P＜0.05). CONCLUSION: Recombinant adenovirus Ad-BDDhFⅧ-GFP can effectively transfect rat ADSC in vitro, which lays an experimental foundation for gene therapy of hemophilia A.

Application of double circular suturing technique (DCST) in the repair of large abdominal wall defects after resection of abdominal wall tumor.

BACKGROUND: The aim of this study was to investigate the clinical effects of repairing large defects using the double circular suturing technique (DCST) after resection of abdominal wall tumor. METHODS: The clinical data of 62 patients (25 men, 37 women; average age 41.7±22.4 years) who underwent DCST between October 2010 and November 2018 for the repair of large abdominal wall defects with anti-adhesion underlay mesh after resection of abdominal wall tumor were retrospectively analyzed. The maximum diameter of abdominal wall defect after resection of abdominal wall tumor was 10.4±5.6 cm. The course of disease was 1-341 months, and the average was 32.4 months. Operative time, postoperative hospitalization time, perioperative complications, tumor recurrence in situ, incidence of postoperative chronic pain, and hernia were recorded. RESULTS: All 62 operations were completed successfully. The operative time was 73.2±31.4 minutes, and the mean postoperative hospitalization time was 9.6 days (range, 2-20 days). In total, 54 patients were followed up postoperatively for a median 6.7 years (range, 0.9-9.0 years). Partial splitting of incisions occurred in 2 patients, fat liquefaction of incisions occurred in 3 patients, and chronic pain occurred in 4 patients. No tumor in situ recurrence, hernia, or other complications were found in any cases in the follow-up. Tumor metastasis occurred in 9 patients with 6 of these patients dying of tumour progression. CONCLUSIONS: With simple operations, short procedure time, few complications, low tumor recurrence rate, and low incidence of postoperative chronic pain, application of DCST in the repair of large abdominal wall defects is effective after resection of abdominal wall tumor.

Structure-Dependent Antibacterial Activity of Amino Acid-Based Supramolecular Hydrogels.

Bacterial infections are currently a major concern to human health. Amino acid-based supramolecular polymer hydrogels, which boast intrinsic antibacterial activity, are an important solution due to their good biocompatibility, cost effectiveness, and tunable structural properties. Herein, we reported three types of transparent supramolecular hydrogel with intrinsic antibacterial activity from self-assembly of commercially available Fmoc-tryptophan (Fmoc-W), Fmoc-methionine (Fmoc-M), and Fmoc-tyrosine (Fmoc-Y). The resulting hydrogels selectively inhibited the growth of Gram-positive bacteria. Moreover, the order of antibacterial activity was Fmoc-W hydrogel > Fmoc-M hydrogel > Fmoc-Y hydrogel. The critical aggregation concentration (CAC) values were found at concentrations of approximately 0.0293, 0.1172, and 0.4688 mM for Fmoc-W, Fmoc-M, and Fmoc-Y, respectively. Transmission electron microscope (TEM) images revealed rigid and aligned nanofibers for Fmoc-W hydrogel, while flexible nanofibers for Fmoc-M hydrogel and Fmoc-Y hydrogel. The results indicated that stronger aggregation capability of the gelator and the synergistic nanostructural morphology with more rigid and aligned nanofibers can lead to higher antibacterial activity of its corresponding hydrogel. In addition, the molecular arrangements of Fmoc-amino acids in the hydrogels may also contribute to their antibacterial activity. These results can guide the rational design, fabrication, and future application of other self-assembled amino acid-based hydrogels with excellent antibacterial activity.

Tailoring bacterial cellulose structure through CRISPR interference-mediated downregulation of galU in Komagataeibacter xylinus CGMCC 2955.

Diverse applications of bacterial cellulose (BC) have different requirements in terms of its structural characteristics. culturing Komagataeibacter xylinus CGMCC 2955, BC structure changes with alterations in oxygen tension. Here, the K. xylinus CGMCC 2955 transcriptome was analyzed under different oxygen tensions. Transcriptome and genome analysis indicated that BC structure is related to the rate of BC synthesis and cell growth, and galU is an essential gene that controls the carbon metabolic flux between the BC synthesis pathway and the pentose phosphate (PP) pathway. The CRISPR interference (CRISPRi) system was utilized in K. xylinus CGMCC 2955 to control the expression levels of galU. By overexpressing galU and interfering with different sites of galU sequences using CRISPRi, we obtained strains with varying expression levels of galU (3.20-3014.84%). By testing the characteristics of BC, we found that the porosity of BC (range: 62.99-90.66%) was negative with galU expression levels. However, the crystallinity of BC (range: 56.25-85.99%) was positive with galU expression levels; galU expression levels in engineered strains were lower than those in the control strains. Herein, we propose a new method for regulating the structure of BC to provide a theoretical basis for its application in different fields.

Permeation of Silver Sulfadiazine Into TEMPO-Oxidized Bacterial Cellulose as an Antibacterial Agent.

Surface oxidation of bacterial cellulose (BC) was done with the TEMPO-mediated oxidation mechanism system. After that, TEMPO-oxidized bacterial cellulose (TOBC) was impregnated with silver sulfadiazine (AgSD) to prepare nanocomposite membranes. Fourier transform infrared spectroscopy (FTIR) was carried out to determine the existence of aldehyde groups on BC nanofibers and X-ray diffraction (XRD) demonstrated the degree of crystallinity. FESEM analysis revealed the impregnation of AgSD nanoparticles at TOBC nanocomposites with the average diameter size ranging from 11 nm to 17.5 nm. The sample OBCS3 showed higher antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli by the disc diffusion method. The results showed AgSD content, dependent antibacterial activity against all tested bacteria, and degree of crystallinity increases with TOBC and AgSD. The main advantage of the applications of TEMPO-mediated oxidation to BC nanofibers is that the crystallinity of BC nanofibers is unchanged and increased after the oxidation. Also enhanced the reactivity of BC as it is one of the most promising method for cellulose fabrication and functionalization. We believe that the novel composite membrane could be a potential candidate for biomedical applications like wound dressing, BC scaffold, and tissue engineering.

Development and antibacterial activities of bacterial cellulose/graphene oxide-CuO nanocomposite films.

The absence of antibacterial activity of bacterial cellulose (BC) restricts its applications in the biomedical field. To introduce antimicrobial properties into BC, we studied the synthesis, structure, and antimicrobial properties of a novel nanocomposite film comprising BC, graphene oxide (GO), and copper-oxide (CuO) nanosheets. The nanocomposite film was synthesized by incorporating GO-CuO nanohybrids into BC matrix through homogenized blending. The CuO nanosheets, with a length range of 50 nm-200 nm and width range of 20 nm-50 nm, which were uniformly grown on the GO along with even distribution of GO-CuO nanohybrids on the surface of the cellulose fibers. The nanocomposites displayed better antibacterial activity against gram-positive than gram-negative bacteria. BC/GO-CuO nanocomposites showed higher antibacterial activity than BC/CuO. We also elucidated the mechanism of antibacterial activity of the nanocomposites. Further, the nanocomposites exhibited biocompatibility towards mice fibroblast cells. The nanocomposites might serve as an excellent source for development of antibacterial materials.

Reusable ternary PVA films containing bacterial cellulose fibers and ε-polylysine with improved mechanical and antibacterial properties.

The combination of high mechanical properties, antibacterial activity and a green synthesis of the polyvinyl alcohol (PVA) based films remains challenging. This study presents a ternary system of PVA films containing bacterial cellulose (BC) and epsilon-polylysine (ε-PL) by a green solution casting method. The prepared composite films showed more than 99% antibacterial properties against both Staphylococcus aureus and Escherichia coli bacteria. Moreover, the films were collected after a single use and were reused twice, which still exhibited strong antibacterial activity. The films showed thermal stability and higher mechanical properties as compared to pure PVA films. In addition, the cytotoxicity of the films was evaluated by MTT assay against NIH 3T3 mouse fibroblast cells. The results showed no toxicity of the films towards tested cells. We believe that these antibacterial films may find applications in active food packaging and biomedical fields.

Identification of Quorum-Sensing Molecules of N-Acyl-Homoserine Lactone in Gluconacetobacter Strains by Liquid Chromatography-Tandem Mass Spectrometry.

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using N-acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. N-acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, Gluconacetobacter xylinus CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. Gluconacetobacter sp. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.

Applications of cellulose and chitin/chitosan derivatives and composites as antibacterial materials: current state and perspectives.

The bacterial infections have always a serious problem to public health. Scientists are developing new antibacterial materials to overcome this problem. Polysaccharides are promising biopolymers due to their diverse biological functions, low toxicity, and high biodegradability. Chitin and chitosan have antibacterial properties due to their cationic nature, while cellulose/bacterial cellulose does not possess any antibacterial activity. Moreover, the insolubility of chitin in common solvents, the poor solubility of chitosan in water, and the low mechanical properties of chitosan have restricted their biomedical applications. In order to solve these problems, chemical modifications such as quaternization, carboxymethylation, cationization, or surface modification of these polymers with different antimicrobial agents, including metal and metal oxide nanoparticles, are carried out to obtain new materials with improved physiochemical and biological properties. This mini review describes the recent progress in such derivatives and composites with potential antibacterial applications.