Preclinical Animal Study and Pilot Clinical Trial of Using Enriched Peripheral Blood-Derived Mononuclear Cells for Intervertebral Disc Degeneration.

Low back pain (LBP) is a leading cause of long-term disability globally. Intervertebral disk degeneration (IVDD) is mainly responsible for discogenic pain in LBP-affected young patients. There is no effective therapy to reverse disease severity and IVDD progression. This study investigates the effect of human peripheral blood-derived mononuclear cells (PBMCs) on pain relief and life quality improvement in IVDD patients. The enriched monocytes of the PBMCs could differentiate into CD14 and CD206 double-positive M2 macrophages in vitro. Preclinical evidence in rats showed that the transplanted PBMCs exhibited anti-inflammatory and moderate tissue-repair effects on controlling IVDD progress in the rat model. The PBMCs significantly steered the aggrecan and type II collagen expressions and attenuated the pro-inflammatory cytokines in the affected disk. Based on the animal results, 36 patients with chronic low back pain (CLBP) were included in clinical trials. The control group was conservative care only, and the experimental group was platelet-rich plasma (PRP) and PBMCs intradiscal injections. We first confirmed the single lumbar disk causing the discogenic pain by provocative discography or magnetic resonance imaging (MRI). Discogenic LBP participants received one intradiscal injection of autologous PBMCs and followed for 6 months. Our clinical trial showed that patients' LBP and disability were significantly ameliorated after the PBMCs transplantation rather than PRP. These preclinical and pilot clinical studies indicate that intradiscal injection of the enriched PBMCs might be a feasible and potential cell therapy to control pain and disability in IVDD patients.

Antimicrobial Peptide Conjugated on Graphene Oxide-Containing Sulfonated Polyetheretherketone Substrate for Effective Antibacterial Activities against Staphylococcus aureus.

In the present study, the antimicrobial peptide nisin was successfully conjugated onto the surface of sulfonated polyetheretherketone (SPEEK), which was decorated with graphene oxide (GO) to investigate its biofilm resistance and antibacterial properties. The PEEK was activated with sulfuric acid, resulting in a porous structure. The GO deposition fully covered the porous SPEEK specimen. The nisin conjugation was accomplished using the crosslinker 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) through a dip-coating method. The surface micrographs of the SPEEK-GO-nisin sample indicated that nisin formed discrete islets on the flat GO surface, allowing both the GO and nisin to perform a bactericidal effect. The developed materials were tested for bactericidal efficacy against Staphylococcus aureus (S. aureus). The SPEEK-GO-nisin sample had the highest antibacterial activity with an inhibition zone diameter of 27 mm, which was larger than those of the SPEEK-nisin (19 mm) and SPEEK-GO (10 mm) samples. Conversely, no inhibitory zone was observed for the PEEK and SPEEK samples. The surface micrographs of the bacteria-loaded SPEEK-GO-nisin sample demonstrated no bacterial adhesion and no biofilm formation. The SPEEK-nisin and SPEEK-GO samples showed some bacterial attachment, whereas the pure PEEK and SPEEK samples had abundant bacterial colonies and thick biofilm formation. These results confirmed the good biofilm resistance and antibacterial efficacy of the SPEEK-GO-nisin sample, which is promising for implantable orthopedic applications.

Total intravenous anesthesia for geriatric hip fracture with severe systemic disease.

PURPOSE: Our study aimed to determine the impact of a novel technique of anesthesia administration on the clinical outcomes and complications in geriatric patients with severe systemic disease undergoing hip surgery. METHODS: We retrospectively identified patients aged > 65 years with severe systemic disease that was a constant of life [American Society of Anesthesiologists (ASA) IV] who underwent surgery for hip fracture between January 2018 and January 2020. The patients were divided into two groups: Group I [fascia iliaca compartment block plus propofol-based total intravenous anesthesia (FICB + TIVA)] and Group II [general anesthesia (GA)]. The primary outcomes were 30-day and 1-year mortality. The secondary outcomes included length of hospital stay, length of intensive care unit (ICU) stay, postoperative morbidity, Visual Analog Scale score, and consumption of analgesics. RESULTS: There was no significant difference in the 30-day mortality (5 vs. 3.8%, p = 0.85) and 1-year mortality (15 vs. 12%, p = 0.73) between the groups. Group I had significantly lower ICU requirements (p = 0.01) and shorter lengths of ICU stay (p < 0.001) and hospital stay (p < 0.001). Moreover, a smaller proportion of patients in Group I required postoperative morphine or oral opiates. CONCLUSION: Geriatric patients who underwent hip surgery under FICB + TIVA required fewer ICU admissions, shorter lengths of ICU and hospital stay, and had lesser postoperative opioid consumption than those who were under GA. Hence, we recommend the novel FICB + TIVA technique for hip fracture surgery in geriatric patients with poor general health status and high surgical risks (ASA IV).

The posterior capsule is distended in dysplastic hips, but the anterior capsule is not.

PURPOSE: In the setting of acetabular dysplasia, the increased translational motion of the femur may damage the labrum and cartilage, as well as stretch the capsule. The purpose of the study was to investigate the relationship between the acetabular coverage and the capsular stiffness by assessing the distension of anterior and posterior joint recesses on the hip computed tomography arthrography. METHODS: One hundred thirty-three patients (138 hips) with a median age of 36 years (range 18-50 years) who received the computed tomography arthrography for evaluation of nonarthritic hip pain in our institute between 2015 and 2017 were retrospectively reviewed. The maximal distance between the anterior/posterior capsule and the anterior femoral head-neck junction/posterior femoral head on the axial imaging of computed tomography arthrography was defined as the width of anterior/posterior joint recess. The width of anterior/posterior joint recess was adjusted with the diameter of the femoral head and was then compared between acetabular dysplasia (lateral center-edge angle < 25°), normal acetabulum (lateral center-edge angle between 25 and 39°), and deep acetabulum (lateral center-edge angle > 39°). In addition, the standard univariate linear regression analysis was used to investigate the relationship between the adjusted width of anterior/posterior joint recess and anterior/posterior coverage of the hip, determined by the anterior/posterior wall index. RESULTS: The adjusted width of posterior joint recess was significantly greater in the acetabular dysplasia group than the normal acetabulum and deep acetabulum groups (p < 0.01 and p = 0.02, respectively). There was no significant difference of the adjusted width of anterior joint recess between the groups (n.s.). The adjusted width of posterior joint recess had a significant but weak negative correlation with the anterior wall index (r = - 0.25, p < 0.001), and no correlation with the posterior wall index (r = - 0.0004, n.s.). There was no significant correlation between the adjusted width of anterior joint recess and the anterior/posterior wall index (r = 0.05, n.s./r = 0.07, n.s.). CONCLUSIONS: The distension of posterior capsule on the computed tomography arthrography was significantly greater in acetabular dysplasia. In addition, there was a significant but weak negative correlation between the distension of posterior capsule and the anterior coverage of the hip. It indicated a looser posterior capsule was observed in a dysplastic hip. The relevance of posterior capsular laxity to clinical outcomes warrants further investigation. Given the fact that the distension of anterior capsule was not significantly higher in acetabular dysplasia, the need of anterior capsular plication in a dysplastic hip should be carefully evaluated. LEVEL OF EVIDENCE: Level III.

Post-operative prophylactic antibiotics in aseptic revision hip and knee arthroplasty: a propensity score matching analysis.

The use of extended antibiotic (EA) prophylaxis (> 24 h) remains controversial in aseptic revision arthroplasty. We sought to determine whether EA prophylaxis reduces the risk of periprosthetic joint infection (PJI) in aseptic revision hip and knee arthroplasty. A total of 2800 patients undergoing aseptic revision hip and knee arthroplasty at five institutional databases from 2008 to 2017 were evaluated. One to two nearest-neighbor propensity score matching analysis was conducted between patients who did and did not receive extended antibiotic prophylaxis. The matching elements included age, sex, body mass index, Charlson comorbidity index, hospital distribution, year of surgery, joint (hip or knee), surgical time, CRP, preoperative hemoglobin, albumin, and length of stay. The primary outcome was the development of PJI, which was assessed at 30 days, 90 days, and 1 year following revision and analyzed separately. A total of 2467 (88%) patients received EA prophylaxis, and 333 (12%) patients received standard antibiotic (SA) prophylaxis (≤ 24 h). In the propensity-matched analysis, there was no difference between patients who received EA prophylaxis and those who did not in terms of 30-day PJI (0.3% vs. 0.3%, p = 1.00), 90-day PJI (1.7% vs. 2.1%, p = 0.62) and 1- year PJI (3.8% vs. 6.0%, p = 0.109). For revision hip, the incidence of PJI was 0.2% vs 0% at 30 days (p = 0.482), 1.6% vs 1.4% at 90 days (p = 0.837), and 3.4% vs 5.1% at 1 year (p = 0.305) in the EA and SA group. For revision knee, the incidence of PJI was 0.4% vs 0.9% at 30 days (p = 0.63), 1.8% vs 3.4% at 90 days (p = 0.331), and 4.4% vs 7.8% at 1 year (p = 0.203) in the EA and SA group. A post hoc power analysis revealed an adequate sample size with a beta value of 83%. In addition, the risks of Clostridium difficile and resistant organism infection were not increased. This multi-institutional study demonstrated no difference in the rate of PJIs between patients who received extended antibiotic prophylaxis and those who did not in aseptic revision arthroplasty. The risk of C. difficile and resistant organism infection was not increased with prolonged antibiotic use.

Total hip arthroplasty has higher complication rates in stiff spine patients: a systematic review and network meta-analysis.

BACKGROUND: Ankylosing spondylitis (AS) and spinal fusion (SF) classified as stiff spines have been associated with the increased rate of complications following total hip arthroplasty (THA). However, the differences between the two cohorts have inconsistent evidence. METHODS: We searched for studies comparing complications among stiff spine patients, including SF and AS, who underwent THA in PubMed/MEDLINE, Embase, Cochrane CENTRAL, Web of Science, and Scopus until March 2021. Studies detailing rates of mechanical complications, aseptic loosening, dislocation, infection, and revisions were included. We performed network meta-analyses using frequentist random-effects models to compare differences between cohorts. We used P-score to rank the better exposure with the lowest complications. RESULTS: Fourteen studies were included in the final analysis. A total of 740,042 patients were included in the systematic review and network meta-analysis. Mechanical complications were highest among SF patients (OR 2.33, 95% CI 1.86, 2.92, p < 0.05), followed by AS patients (OR 1.18, 95% CI 0.87, 1.61, p = 0.82) compared to controls. Long Spinal Fusions had the highest aseptic loosening (OR 2.33, 95% CI 1.83, 2.95, p < 0.05), dislocations (OR 3.25, 95% CI 2.58, 4.10, p < 0.05), infections (OR 2.14, 95% CI 1.73, 2.65, p < 0.05), and revisions (OR 5.25, 95% CI 2.23, 12.32, p < 0.05) compared to AS and controls. Our results suggested that SF with longer constructs may be associated with higher complications in THA patients. CONCLUSIONS: THAs following SFs have higher mechanical complications, aseptic loosening, dislocations, and infections, especially with longer constructs. AS patients may have fewer complications compared to this cohort.

Prismatic Silver Nanoparticles Decorated on Graphene Oxide Sheets for Superior Antibacterial Activity.

Spherical silver nanoparticles (Ag NPs) and silver nanoprisms (Ag NPrsms) were synthesized and decorated on graphene oxide (GO) nanosheets. The Ag contents were 29% and 23% in the GO−Ag NPs and GO−Ag NPrsms, respectively. The Ag NPrsms exhibited stronger (111) crystal signal than Ag NPs. The GO−Ag NPrsms exhibited higher Ag (I) content (75.6%) than GO-Ag NPs (69.9%). Increasing the nanomaterial concentration from 25 to 100 µg mL−1 improved the bactericidal efficiency, and the antibacterial potency was in the order: GO−Ag NPrsms > GO−Ag NPs > Ag NPrsms > Ag NPs > GO. Gram-positive Staphylococcus aureus (S. aureus) was more vulnerable than Gram-negative Escherichia coli (E. coli) upon exposure to these nanomaterials. The GO−Ag NPrsms demonstrated a complete (100%) bactericidal effect against S. aureus at a concentration of 100 µg mL−1. The GO−Ag composites outperformed those of Ag or GO due to the synergistic effect of bacteriostatic Ag particles and GO affinity toward bacteria. The levels of reactive oxygen species produced in the bacteria−nanomaterial mixtures were highly correlated to the antibacterial efficacy values. The GO−Ag NPrsms are promising as bactericidal agents to suppress biofilm formation and inhibit bacterial infection.

Antibacterial Activity Studies of 3D-Printing Polyetheretherketone Substrates with Surface Growth of 2D TiO2/ZnO Rodlike Arrays.

Heterogeneous metal implants have been applied in clinical treatments of skeletal wounds, but their low antibacterial properties and the possibility of a release of metal ions may have harmful influences on the human body. Therefore, a polymer implant with low cost, high safety, an elastic modulus similar to that of human bone, and a good antibacterial property must be produced for orthopedic treatments. In this study, the surface of a 3D-printed polyetheretherketone (PEEK) disk was grown with ZnO/TiO2 rodlike arrays using a chemical bath deposition. X-ray diffraction patterns and transmission electron microscopy images showed that TiO2/ZnO rodlike arrays were deposited onto the PEEK substrate. With the direct absorption of antibiotic agents onto the surface of TiO2/ZnO/PEEK samples, their antibacterial performances greater than the values of minimum inhibitory concentration required to inhibit the growth of 90% of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) remained for around 10 days. The concentration of Zn2+ ions in a buffer solution is reduced with the coating of a TiO2 layer on a ZnO rodlike array. The sample with absorption from a mixture containing ampicillin and vancomycin salts with a weight ratio of 1:1 had the best inhibitory effect on the growth of E. coli and S. aureus.

Preparation and Characterization of Thin-Film Solar Cells with Ag/C60/MAPbI3/CZTSe/Mo/FTO Multilayered Structures.

New solar cells with Ag/C60/MAPbI3/Cu2ZnSnSe4 (CZTSe)/Mo/FTO multilayered structures on glass substrates have been prepared and investigated in this study. The electron-transport layer, active photovoltaic layer, and hole-transport layer were made of C60, CH3NH3PbI3 (MAPbI3) perovskite, and CZTSe, respectively. The CZTSe hole-transport layers were deposited by magnetic sputtering, with the various thermal annealing temperatures at 300 °C, 400 °C, and 500 °C, and the film thickness was also varied at 50~300 nm The active photovoltaic MAPbI3 films were prepared using a two-step spin-coating method on the CZTSe hole-transport layers. It has been revealed that the crystalline structure and domain size of the MAPbI3 perovskite films could be substantially improved. Finally, n-type C60 was vacuum-evaporated to be the electronic transport layer. The 50 nm C60 thin film, in conjunction with 100 nm Ag electrode layer, provided adequate electron current transport in the multilayered structures. The solar cell current density-voltage characteristics were evaluated and compared with the thin-film microstructures. The photo-electronic power-conversion efficiency could be improved to 14.2% when the annealing temperature was 500 °C and the film thickness was 200 nm. The thin-film solar cell characteristics of open-circuit voltage, short-circuit current density, fill factor, series-resistance, and Pmax were found to be 1.07 V, 19.69 mA/cm2, 67.39%, 18.5 Ω and 1.42 mW, respectively.

Development and validation of a caregiving needs inventory for family members before their older relative's knee joint-replacement surgery.

PURPOSE: This study had two purposes: to develop an instrument for assessing family members' caregiving needs before their older relative's knee joint-replacement surgery and to determine instrument psychometrics. METHODS: In phase 1 of this validation study, we generated 34 items based on previous interviews with 138 family caregivers of patients with knee osteoarthritis (OA), an intensive literature review, and the authors' clinical experiences. In phase 2, we examined the content and face validities of the 34-item Family Members' Caring Needs Inventory (inventory) to develop a 32-item inventory. In phase 3, 150 family members of outpatients with knee OA were recruited from three hospitals in northern Taiwan and surveyed with the inventory to determine its internal consistency reliability and test-retest reliability. RESULTS: The final 30-item inventory had excellent content and face validities. Its factor analysis yielded a five-factor solution, accounting for 82.9% of the variance. The inventory had Cronbach's α = 0.97 and intraclass correlation coefficient = 0.93, indicating very high internal consistency reliability and test-retest reliability. CONCLUSIONS: The inventory was perceived as easy to complete and yielded highly acceptable validity and reliability levels. After cross-cultural adaptation, this tool may be used to assess family members' caregiving needs before their relative's knee-replacement surgery.IMPLICATIONS FOR REHABILITATIONThe role of family members and spouses in supporting patients with osteoarthritis (OA) is crucial.After cross-cultural adaptation, the Family Members' Caring Needs Inventory may be used by health care providers to assess and provide relevant information to meet the needs of family members caring for an older relative with knee OA.This assessment and specific caregiving information for family members of older knee OA patients may promote patients' quality of life and decrease their OA-related burden.

Facilitating GL13K Peptide Grafting on Polyetheretherketone via 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide: Surface Properties and Antibacterial Activity.

In the present work, the antimicrobial peptide (AMP) of GL13K was successfully coated onto a polyetheretherketone (PEEK) substrate to investigate its antibacterial activities against Staphylococcus aureus (S. aureus) bacteria. To improve the coating efficiency, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was mixed with a GL13K solution and coated on the PEEK surface for comparison. Both energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) data confirmed 30% greater peptide coating on PEEK/GL13K-EDC than PEEK without EDC treatment. The GL13K graft levels are depicted in the micrograms per square centimeter range. The PEEK/GL13K-EDC sample showed a smoother and lower roughness (Rq of 0.530 µm) than the PEEK/GL13K (0.634 µm) and PEEK (0.697 µm) samples. The surface of the PEEK/GL13K-EDC was more hydrophilic (with a water contact angle of 24°) than the PEEK/GL13K (40°) and pure PEEK (89°) samples. The pure PEEK disc did not exhibit any inhibition zone against S. aureus. After peptide coating, the samples demonstrated significant zones of inhibition: 28 mm and 25 mm for the PEEK/GL13K-EDC and PEEK/GL13K samples, respectively. The bacteria-challenged PEEK sample showed numerous bacteria clusters, whereas PEEK/GL13K contained a little bacteria and PEEK/GL13K-EDC had no bacterial attachment. The results confirm that the GL13K peptide coating was able to induce antibacterial and biofilm-inhibitory effects. To the best of our knowledge, this is the first report of successful GL13K peptide grafting on a PEEK substrate via EDC coupling. The present work illustrates a facile and promising coating technique for a polymeric surface to provide bactericidal activity and biofilm resistance to medical implantable devices.

The impact of systemic lupus erythematosus on the risk of infection after total hip arthroplasty: a nationwide population-based matched cohort study.

BACKGROUND: We aimed to assess the impact of systemic lupus erythematosus (SLE) on the risk of infection after total hip arthroplasty (THA). METHODS: We identified patients undergoing primary THA (1996-2013) in Taiwan National Health Insurance Research Database (NHIRD). Patients were then divided into the SLE and control groups according to the diagnosis of SLE. We used 1:1 propensity score to match the control to the SLE group by age, sex, and comorbidities. The primary outcome was infection, including early and late superficial wound infection and periprosthetic joint infection (PJI). The secondary outcome was in-hospital complications. RESULTS: We enrolled 325 patients in each group. In the primary outcome, the incidence of early superficial wound infection and PJI was comparable between the SLE and matched-control group. However, the incidence of late superficial wound infection and PJI in the SLE group was higher than that in matched-control group (11.4% vs. 5.5%, P = 0.01; 5.2% vs 2.2%, P = 0.04, respectively). Furthermore, the SLE group had a higher risk for late superficial wound infection and PJI (hazard ratio = 2.37, 95% confidence interval (CI) 1.35-4.16; HR = 2.74, 95% CI 1.14-6.64, respectively) than the matched-control. Complications other than infection and in-hospital mortality cannot be compared because of very low incidence. CONCLUSIONS: SLE is a risk factor for developing late superficial wound infection and PJI, but not for early postoperative complications following THA. Clinical presentations should be monitored to avoid misdiagnosis of PJI in SLE patients after THA.

Increased incidence, morbidity, and mortality in cirrhotic patients with hip fractures: A nationwide population-based study.

OBJECTIVES: Hip fractures mostly require surgical treatment and are associated with increased health-care costs and mortality rates. Patients with cirrhosis have low bone marrow density and inferior immune status which contribute to a higher fracture rate and higher surgical complication rate. This population-based study evaluated the prevalence, complication, and mortality rates due to hip fractures in cirrhotic patients. METHODS: Taiwan National Health Insurance Research Database data were used. The study group included 117,129 patients with hip fractures diagnosed from 2004 to 2010, including 4048 patients with cirrhosis. The overall prevalence, morbidity, and mortality rates of the cirrhosis group with hip fractures were compared with the rates of a general group with hip fractures. RESULTS: The cirrhosis group patients were younger than the general group patients (71.2 vs. 73.96 years, p < 0.001). The annual incidence of hip fractures in the cirrhosis and general groups was 46-54 and 7-7.5 per 10,000 person-years, respectively, with an incidence rate ratio of 6.95 (95% confidence interval 6.74-7.18). The rates of infection, urinary tract infection, and peptic ulcer disease were higher in the cirrhosis group (3.46% vs. 1.91%, 9.56% vs. 9.11%, and 8.05% vs. 3.55%, respectively; all p < 0.001). The mortality rate after hip fracture was also higher in the cirrhosis group than in the general group (within 3 months: 8.76-12.64% vs. 4.96-5.30% and within 1 year: 29.72-37.99% vs. 12.84-14.57%). Conclusion: Cirrhotic patients with hip fractures were relatively younger; had a seven times higher annual hip fracture incidence; had higher complication rates of infection, urinary tract infection, and peptic ulcer disease; and had two to three times higher a mortality rate at 3 months and 1 year. Clinicians should pay particular attention to the possibility of osteoporosis and hip fractures in patients with liver cirrhosis. LEVEL OF EVIDENCE: Level III, case-control study.

Weight control in older adults with knee osteoarthritis: a qualitative study.

BACKGROUND: Knee osteoarthritis (OA) affects mostly older adults and its primary risk factor is obesity. This study sought to understand weight-control strategies, facilitators of and barriers toward weight control in older adults with knee OA who preferred not to undergo physician-recommended total knee arthroplasty. METHODS: For this qualitative descriptive study, older outpatients (N = 118) were recruited from orthopedic clinics at three hospitals. Data were collected through face-to face, individual in-depth interviews using a semi-structured interview guide and analyzed using content analysis. RESULTS: Among participants, only 25.4% had body weight in the normal range and 55.9% reported having controlled their weight. Their most common weight-control strategies were to control diet and to exercise and control diet together. Weight control was facilitated by desiring good health, wanting to improve walking or movement, perceiving that they had gained weight, wanting to look good, and advice from healthcare providers. Common barriers to participants' weight control were perceiving that dietary control was not needed, controlling appetite was difficult, dietary control was difficult, and not eating was physically uncomfortable. CONCLUSIONS: Our findings help healthcare providers understand how older adults with knee OA perceive weight control and serve as a reference for developing weight-control programs. Health care providers can integrate these identified facilitators and barriers into a weight-control intervention program. The importance of weighing oneself every day, the meaning of body mass index, consulting with a dietician regularly to control weight, and providing appropriate knowledge about aging and weight control should also be included in any weight-control intervention program.

Size-Dependent Antibacterial Activity of Silver Nanoparticle-Loaded Graphene Oxide Nanosheets.

A series of graphene oxide (GO) suspensions with different particle sizes (<100 nm, ~100 nm, ~1 µm and >1 µm) were successfully fabricated after 0, 30, 60 and 120 min of sonication, respectively. The antibacterial properties of GO suspensions showed that >1 µm GO size resulted in a loss of nearly 50% of bacterial viability, which was higher than treatment by ~100 nm GO size (25%) towards Escherichia coli (E. coli). Complete entrapment of bacteria by the larger GO was observed in transmission electron microscopy (TEM). Silver nanoparticles (Ag NPs) were doped onto GO samples with different lateral sizes to form GO-Ag NP composites. Resulting larger GO-Ag NPs showed higher antibacterial activity than smaller GO-Ag NPs. As observed by Fourier transform infrared spectroscopy (FTIR), the interaction between E. coli and GO occurred mainly at the outer membrane, where membrane amino acids interact with hydroxyl and epoxy groups. The reactive oxygen species (ROS) and the considerable penetration of released Ag+ into the inner bacterial cell membrane result in loss of membrane integrity and damaged morphology. The present work improves the combined action of GO size effect with constant Ag loadings for potential antibacterial activity.

Effects of Annealing on Characteristics of Cu2ZnSnSe4/CH3NH3PbI3/ZnS/IZO Nanostructures for Enhanced Photovoltaic Solar Cells.

This paper presents new photovoltaic solar cells with Cu2ZnSnSe4/CH3NH3PbI3(MAPbI3)/ZnS/IZO/Ag nanostructures on bi-layer Mo/FTO (fluorine-doped tin oxide) glasssubstrates. The hole-transporting layer, active absorber layer, electron-transporting layer, transparent-conductive oxide layer, and top electrode-metal contact layer, were made of Cu2ZnSnSe4, MAPbI3 perovskite, zincsulfide, indium-doped zinc oxide, and silver, respectively. The active absorber MAPbI3 perovskite film was deposited on Cu2ZnSnSe4 hole-transporting layer that has been annealed at different temperatures. TheseCu2ZnSnSe4 filmsexhibitedthe morphology with increased crystal grain sizesand reduced pinholes, following the increased annealing temperature. When the perovskitefilm thickness was designed at 700 nm, the Cu2ZnSnSe4 hole-transporting layer was 160 nm, and the IZO (indium-zinc oxide) at 100 nm, and annealed at 650 °C, the experimental results showed significant improvements in the solar cell characteristics. The open-circuit voltage was increased to 1.1 V, the short-circuit current was improved to 20.8 mA/cm2, and the device fill factor was elevated to 76.3%. In addition, the device power-conversion efficiency has been improved to 17.4%. The output power Pmax was as good as 1.74 mW and the device series-resistance was 17.1 Ω.

Synergistic Antibacterial Activity of Silver-Loaded Graphene Oxide towards Staphylococcus Aureus and Escherichia Coli.

In this study, the physicochemical and surface properties of the GO-Ag composite promote a synergistic antibacterial effect towards both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. Aureus) bacteria. GO-Ag NPs have a better bactericidal effect on E. coli (73%) and S. Aureus (98.5%) than pristine samples (pure Ag or GO). Transmission electron microscopy (TEM) confirms that the GO layers folded entire bacteria by attaching to the membrane through functional groups, while the Ag NPs penetrated the inner cell, thus damaging the cell membrane and leading to cell death. Cyclic voltammetry (CV) tests showed significant redox activity in GO-Ag NPs, enabling good catalytic performance towards H2O2 reduction. Strong reactive oxygen species (ROS) in GO-Ag NPs suggests that ROS might be associated with bactericidal activity. Therefore, the synergy between the physicochemical effect and ROS production of this material is proposed as the mechanism of its antibacterial activity.

Study of High Performance Sulfonated Polyether Ether Ketone Composite Electrolyte Membranes.

In this study, high performance composite electrolyte membranes were prepared from polyether ether ketone polymeric material. An initial sulfonation reaction improved the membrane hydrophilicity and its water absorbability and thus enhanced the ionic conductivity in electrochemical cells. Protonic conductivity was improved from 10-4 to 10-2 S cm-1 with an increasing sulfonation time from 72 to 175 h. The effects of blending nano SiO2 into the composite membranes were devoted to improve thermal and mechanical properties, as well as methanol permeability. Methanol permeability was reduced to 3.1 × 10-7 cm2 s-1. Finally, a further improvement in ionic conductivity was carried out by a supercritical carbon dioxide treatment under 20 MPa at 40°C for 30 min with an optimum SiO2 blend ratio of 10 wt-%. The plasticizing effect by the Lewis acid-base interaction between CO2 and electron donor species on polymer chains decreased the glass transition and melting temperatures. The results show that sulfonated composite membranes blended with SiO2 and using a supercritical carbon dioxide treatment exhibit a lower glass transition temperature, higher ionic conductivity, lower methanol permeability, good thermal stability, and strong mechanical properties. Ionic conductivity was improved to 1.55 × 10-2 S cm-1. The ion exchange capacity and the degree of sulfonation were also investigated.

Osteoblast Biocompatibility and Antibacterial Effects Using 2-Methacryloyloxyethyl Phosphocholine-Grafted Stainless-Steel Composite for Implant Applications.

Poor osteogenesis and bacterial infections lead to an implant failure, so the enhanced osteogenic and antimicrobial activity of the implantable device is of great importance in orthopedic applications. In this study, 2-methacryloyloxyethyl phosphocholine (MPC) was grafted onto 316L stainless steel (SS) using a facile photo-induced radical graft polymerization method via a benzophenone (BP) photo initiator. Atomic force microscopy (AFM) was employed to determine the nanoscale morphological changes on the surface. The grafted BP-MPC layer was estimated to be tens of nanometers thick. The SS-BP-MPC composite was more hydrophilic and smoother than the untreated and BP-treated SS samples. Staphylococcus aureus (S. aureus) bacteria binding onto the SS-BP-MPC composite film surface was significantly reduced compared with the pristine SS and SS-BP samples. Mouse pre-osteoblast (MC3T3-E1) cells showed good adhesion on the MPC-modified samples and better proliferation and metabolic activity (73% higher) than the pristine SS sample. Biological studies revealed that grafting MPC onto the SS substrate enhanced the antibacterial efficiency and also retained osteoblast biocompatibility. This proposed procedure is promising for use with other implant materials.

Antibacterial Application on Staphylococcus aureus Using Antibiotic Agent/Zinc Oxide Nanorod Arrays/Polyethylethylketone Composite Samples.

In this study, zinc oxide (ZnO) nanorod arrays as antibiotic agent carriers were grown on polyetheretherketone (PEEK) substrates using a chemical synthesis method. With the concentration of ammonium hydroxide in the precursor solution kept at 4 M, ZnO nanorod arrays with diameters in the range of 100-400 nm and a loading density of 1.7 mg/cm2 were grown onto the PEEK substrates. Their drug release profiles and the antibacterial properties of the antibiotic agent/ZnO/PEEK samples in the buffer solution were investigated. The results showed that the concentrations of antibiotic agents (ampicillin or vancomycin) released from the samples into the buffer solution were higher than the value of minimum inhibitory concentration of 90% for Staphylococcus aureus within the 96 h test. The bioactivities of ampicillin and vancomycin on substrates also showed around 40% and 80% on the Staphylococcus aureus, respectively. In the antibacterial activity test, sample with the suitable loading amount of antibiotic agent had a good inhibitory effect on the growth of Staphylococcus aureus.