Effect of backstroke ledge on backstroke start technique for water entry.

This study aimed to investigate how the use of a backstroke ledge (BSL) affects backstroke start performance in terms of flight distance and water entry posture in competitive backstroke swimmers. Ten male swimmers performed a maximum of 15 m in backstroke, starting with or without a BSL. Two 120 Hz and one 60 Hz video cameras were used to analyse the kinematic variables and angular momentum of the whole body. Using a BSL reduced the time to reach 5 and 15 m compared with not using a BSL (p < 0.04). Using a BSL heightened vertical position of the centre of mass (CM) at take-off, lengthened flight distance, and increased angular momentum (p < 0.02). Additionally, the lower limb entry angle was larger, and the hole entry posture angle was smaller with a BSL than without a BSL (p < 0.04). These results suggest that a high CM position at the start of the backstroke with a BSL increased the flight distance, and a large angular momentum enabled hole entry as well as improved the horizontal velocity after water entry. Hence, increases in flight distance and velocity after water entry were contributing factors in improving the start performance of the backstroke when using a BSL.

Electrical Stimuli-Responsive Decomposition of Layer-by-Layer Films Composed of Polycations and TEMPO-Modified Poly(acrylic acid).

We previously reported that layer-by-layer (LbL) film prepared by a combination of 2,2,6,6-tetramethylpiperidinyl N-oxyl (TEMPO)-modified polyacrylic acid (PAA) and polyethyleneimine (PEI) were decomposed by application of an electric potential. However, there have been no reports yet for other polycationic species. In this study, LbL films were prepared by combining various polycationics (PEI, poly(allylamine hydrochloride) (PAH), poly(diallydimethylammonium chloride) (PDDA), and polyamidoamine (PAMAM) dendrimer) and TEMPO-PAA, and the decomposition of the thin films was evaluated using cyclic voltammetry (CV) and constant potential using an electrochemical quartz crystal microbalance (eQCM). When a potential was applied to an electrode coated on an LbL thin film of polycations and TEMPO-PAA, an oxidation potential peak (Epa) was obtained around +0.6 V vs. Ag/AgCl in CV measurements. EQCM measurements showed the decomposition of the LbL films at voltages near the Epa of the TEMPO residues. Decomposition rate was 82% for the (PEI/TEMPO-PAA)5 film, 52% for the (PAH/TEMPO-PAA)5 film, and 49% for the (PDDA/TEMPO-PAA)5 film. It is considered that the oxoammonium ion has a positive charge, and the LbL films were decomposed due to electrostatic repulsion with the polycations (PEI, PAH, and PDDA). These LbL films may lead to applications in drug release by electrical stimulation. On the other hand, the CV of the (PAMAM/TEMPO-PAA)5 film did not decompose. It is possible that the decomposition of the thin film is not promoted, probably because the amount of TEMPO-PAA absorbed is small.

Physiological Responses and Stroke Variables during Arm Stroke Swimming Using Critical Stroke Rate in Competitive Swimmers.

The current study examined the physiological responses and stroke variables at critical stroke rate (CSR), 105% CSR, and 110% CSR in order to utilize CSR for prescription arm stroke swimming. Nine male national-level collegiate swimmers performed an all-out 200 m and 400 m for determining the CSR. Participants performed three sets of 6 × 100 m (with 10 s of rest between each bout), the stroke rate for each set was enforced at CSR, 105% CSR, and 110% CSR. Mean swimming velocity, heart rate, and rate of perceived exertion were found to increase with each set (p < 0.05). Blood lactate concentration did not differ between the CSR and the 105% CSR (3.3 ± 1.4 vs. 3.5 ± 1.5 mmol/L) but was higher in 110% CSR (5.1 ± 1.6 mmol/L) than in the other two sets (p < 0.05). There was no difference in the stroke rate between all bouts in each set, and the stroke length did not change from the second to sixth bout in each set. This study suggested that training intensity for CSR and 105% CSR correspond to threshold level, and 110% CSR corresponds to high-intensity training level. It was also suggested that training in the CSR−110% CSR range could be performed without regard to SL reduction.

Advanced Age is not a Risk Factor for Mortality in Patients with Bacteremia Caused by Extended-Spectrum ß-Lactamase-Producing Organisms: a Multicenter Cohort Study.

A 5-year multicenter retrospective cohort study was conducted across six hospitals in Niigata, Japan. Patients (n = 179) with bacteremia due to extended-spectrum ß-lactamase (ESBL)producing organisms were included in the study. The rates of appropriate carbapenem prescription were 61% (n = 41) in patients aged 65-84 years and 89% (n = 31) in those aged ≥ 85 years. Patients aged ≥ 85 years were significantly more likely to receive carbapenem than their younger counterparts. After propensity score matching, 65 patients were assigned to two groups based on age (65-84 years or ≥ 85 years). Multivariate regression analysis showed that other sites of infection had a positive association with 30-day mortality (odds ratio [OR], 27.50; 95% confidence interval [CI], 2.90-260.00) and biliary tract infection tended to have a positive association with 30-day mortality (OR, 8.90; 95% CI, 0.88- 89.90) compared with urinary tract infection. However, an age ≥ 85 years was not associated with 30-day mortality. Elderly patients aged ≥ 85 years were more likely to be treated with carbapenem; however, old age was not associated with 30-day mortality when bacteremia was caused by ESBLproducing organisms. These results may help clinicians justify withholding carbapenem in patients aged ≥ 85 years.

Utilizing Video versus Direct Laryngoscopy to Intubate Simulated Newborns while Contained within the Incubator: A Randomized Crossover Study.

OBJECTIVE: The use of video laryngoscopy for intubating neonates in ergonomically challenging settings has not been studied well. We aimed to assess the usefulness of video laryngoscopy for experienced neonatologists to intubate neonatal manikins in incubators via side hand ports or head window. STUDY DESIGN: In this randomized crossover trial at three neonatal intensive care units in Japan, 27 neonatologists were randomized into two groups, namely, those intubating neonatal simulators using video laryngoscopy and then using direct laryngoscopy, or vice versa. The intubations were performed via hand ports or head window without opening top and side walls in incubators in two manikin positions (rotated 90° or unrotated). Glottis visualization (0-100%), success rate, intubation time, and ease of laryngoscopy (from 1 [very difficult] to 10 [very easy]) were compared between video laryngoscopy and direct laryngoscopy. Generalized linear models were used for the analyses. RESULTS: This study assessed 108 intubations performed by 27 neonatologists. The use of video laryngoscopy improved the glottis visualization by 14% (95% confidence interval, 7.4-20%; p < 0.01) and easiness scores of laryngoscopy by 0.8 (0.2-1.4; p < 0.01), but did not reduce the intubation time. CONCLUSION: Video laryngoscopy is useful for experienced neonatologists for intubating neonatal manikins in incubators without opening the top or side walls.

Umbilical catheterization training: Tissue hybrid versus synthetic trainer.

BACKGROUND: This study of umbilical catheterization deliberate practice training compared skill and knowledge outcomes of umbilical catheterization using a tissue-hybrid simulator (REAL) versus a synthetic simulated umbilical cord task trainer (ART). METHODS: This was a prospective randomized control study. Pediatric residents were randomized to REAL or ART umbilical catheterization deliberate practice training. Pre-post-training changes in skill performance and knowledge scores for REAL and ART groups were compared. Fidelity of REAL and ART were compared by neonatologists. RESULTS: Twenty-seven pediatric residents completed training. Post-training mean skill scores were improved compared to pre-test scores (REAL, P < 0.001; ART, P < 0.0001). Post-training skill, knowledge, and self-efficacy scores were not different between the REAL and ART groups. Fidelity of REAL was higher than ART for neonatologists (P < 0.01). CONCLUSIONS: The face validity of REAL was superior to ART, but resident umbilical cord deliberate practice training demonstrated no difference in skill, knowledge, and self-efficacy improvements between REAL and ART. Further studies on real patients are needed to evaluate the impact of using real or simulated umbilical cords for umbilical venous catheter/umbilical arterial catheter training.

Does Quick Sepsis-Related Organ Failure Assessment Suggest the Use of Initial Empirical Carbapenem Therapy in Bacteremia Caused by Extended-Spectrum ß-Lactamase-Producing Bacteria? :A Multicenter Case-Control Study.

We hypothesized that quick Sequential Organ Failure Assessment (qSOFA) would be associated with 30-day mortality in bacteremia caused by extended-spectrum ß-lactamase (ESBL)-producing bacteria and might be a selection criterion for the use of carbapenem as initial empirical therapy. A multicenter retrospective study was conducted in six hospitals. All patients who had bacteremia due to ESBL-producing bacteria were included in the study. Multivariable logistic regression analysis was performed to analyze 30-day mortality as the main outcome. A total of 203 adult patients were identified with bacteremia caused by ESBL-producing Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis. In multivariate logistic regression analysis, bacteremia caused by ESBL-producing K. pneumoniae or P. mirabilis (odds ratio [OR] 5.07, 95% confidence interval [CI] 1.64-15.56), underlying liver disease (OR 3.38, 95% CI 1.09-10.00), and underlying solid cancer (OR 3.45, 95% CI 1.27-9.69) were associated with 30-day mortality. In a subgroup analysis, empirical non-carbapenem therapy was associated with 30-day mortality in bacteremia caused by ESBL-producing K. pneumoniae or P. mirabilis. Our results suggest that the qSOFA score is not a selection criterion for the use of carbapenem in initial empirical therapy.

Voltammetric Response of Alizarin Red S-Confined Film-Coated Electrodes to Diol and Polyol Compounds: Use of Phenylboronic Acid-Modified Poly(ethyleneimine) as Film Component.

Alizarin red S (ARS) was confined in layer-by-layer (LbL) films composed of phenylboronic acid-modified poly(ethyleneimine) (PBA-PEI) and carboxymethylcellulose (CMC) to study the voltammetric response to diol and polyol compounds. The LbL film-coated gold (Au) electrode and quartz slide were immersed in an ARS solution to uptake ARS into the film. UV-visible absorption spectra of ARS-confined LbL film suggested that ARS formed boronate ester (ARS-PBS) in the film. The cyclic voltammetry of the ARS-confined LbL film-coated electrodes exhibited oxidation peaks at -0.50 and -0.62 V, which were ascribed to the oxidation reactions of ARS-PBS and free ARS, respectively, in the LbL film. The peak current at -0.62 V increased upon the addition of diol or polyol compounds such as L-dopa, glucose, and sorbitol into the solution, depending on the concentration, whereas the peak current at -0.50 V decreased. The results suggest a possible use of ARS-confined PBA-PEI/CMC LbL film-coated Au electrodes for the construction of voltammetric sensors for diol and polyol compounds.

Alizarin Red S-Confined Layer-By-Layer Films as Redox-Active Coatings on Electrodes for the Voltammetric Determination of L-Dopa.

The preparation of redox-active coatings is a key step in fabricating electrochemical biosensors. To this goal, a variety of coating materials have been used in combination with redox-active compounds. In this study, alizarin red S (ARS) was confined in layer-by-layer (LbL) films composed of poly(ethyleneimine) (PEI) and carboxymethylcellulose (CMC) to study the redox properties. A gold (Au) disc electrode coated with PEI/CMC LbL film was immersed in an ARS solution to uptake ARS into the film. ARS was successfully confined in the LbL film through electrostatic interactions. The cyclic voltammogram (CV) of ARS-confined PEI/CMC film-coated electrodes thus prepared exhibited redox waves in the potential range from -0.5 to -0.7 V originating from 9,10-anthraquinone moiety in ARS, demonstrating that ARS preserves its redox activity in the LbL film. An additional oxidation peak appeared around -0.4 V in the CV recorded in the solution containing phenylboronic acid (PBA), due to the formation of a boronate ester of ARS (ARS-PBA) in the film. The oxidation peak current at -0.4 V decreased upon addition of 3,4-dihydroxyphenylalanine (L-dopa) to the solution. Thus, the results suggest a potential use of the ARS-confined PEI/CMC films for constructing voltammetric sensors for L-dopa.

A Case of Fatal Pulmonary Hypoplasia with Congenital Diaphragmatic Hernia, Thoracic Myelomeningocele, and Thoracic Dysplasia.

Background Congenital diaphragmatic hernia (CDH) is fatal in severe cases of pulmonary hypoplasia. We experienced a fatal case of pulmonary hypoplasia due to CDH, thoracic myelomeningocele (MMC), and thoracic dysplasia. This constellation of anomalies has not been previously reported. Case Report A male infant with a prenatal diagnosis of thoracic MMC with severe hydrocephalus and scoliosis was born at 36 weeks of gestation. CDH was found after birth and the patient died of respiratory failure due to pulmonary hypoplasia and persistent pulmonary hypertension of the newborn at 30 hours of age despite neonatal intensive care. An autopsy revealed a left CDH without herniation of the liver or stomach into the thoracic cavity, severe hydrocephalus, Chiari malformation type II, MMC with spina bifida from Th4 to Th12, hemivertebrae, fused ribs, deformities of the thoracic cage and legs, short trunk, and agenesis of the left kidney. Conclusion We speculate that two factors may be associated with the severe pulmonary hypoplasia: decreased thoracic space due to the herniation of visceral organs caused by CDH and thoracic dysplasia due to skeletal deformity and severe scoliosis.

Development and Biosensor Applications of Novel Functional Electrodes.

Phenylboronic acid (PBA) derivatives have been used as alternatives to enzymes in the development of sugar-sensitive systems because the optical and electrochemical properties of these derivatives are significantly modulated upon sugar binding. This article reviews the voltammetric properties of sugar sensors prepared using dithiobis (4-butyrylamino-m-phenylboronic acid) (DTBA-PBA)-modified electrodes and PBA-appended layer-by-layer film-modified electrodes. In addition, the redox properties of reduced graphene oxide (rGO)-modified glassy carbon electrodes (GCEs) are discussed. The surface of a gold electrode was modified with a monolayer of DTBA-PBA to prepare sugar-sensitive electrodes. The modified electrodes exhibited attenuated cyclic voltammograms for Fe(CN)63-/4- in the presence of sugars at neutral pH as a result of their binding to DTBA-PBA on the electrode. Useful calibration curves were obtained for determining 3-300 mM D-glucose and 0.3-30 mM D-fructose. Similarly, gold electrodes coated with multilayer films composed of PBA-modified poly(allylamine hydrochloride) and carboxymethylcellulose exhibited a sugar-dependent response at neutral pH. The dynamic range of these modified electrodes was 0.1-300 mM for D-glucose and D-fructose. The surface of GCE was modified with rGO to evaluate the electrochemical response of the modified GCE to hydrogen peroxide (H2O2). The rGO-modified electrodes exhibited significantly higher responses in the redox reactions of H2O2 compared with the response of an unmodified GCE.

Evaluation of two glucose meters and interference corrections for screening neonatal hypoglycemia.

BACKGROUND: Many neonatal intensive care and maternal units still use self-monitoring of blood glucose (SMBG) devices as a tool to aid diagnosis despite the introduction of point-of-care testing (POCT) devices, which are known to have higher accuracy. We evaluated the performance of two glucose meters, the StatStrip (Nova Biomedical), a POCT device, and the Medisafe Mini (Terumo), an SMBG device, to detect hypoglycemia in neonates. In addition, we evaluated the interference of hematocrit, acetaminophen and ascorbic acid. METHODS: Whole blood samples were drawn from neonates who were at risk of hypoglycemia and analyzed with the StatStrip and Medisafe Mini. The results were further confirmed with blood gas analyzers ABL825 and BM6050. To evaluate the interference of hematocrit, acetaminophen and ascorbic acid, concentrated solutions of glucose and interfering substances were gravimetrically prepared and analyzed. RESULTS: Among the 222 blood samples analyzed, results from the StatStrip were more closely aligned to those of the ABL825 at all levels of glucose than the Medisafe Mini. CONCLUSION: StatStrip appears to be unaffected by hematocrit, ascorbic acid or acetaminophen. We recommend its use in neonates in hospital. Further studies are required to identify other interference effects.

Risk of respiratory syncytial virus infection in infants with congenital cystic lung disease.

BACKGROUND: Congenital cystic lung disease (CCLD), which includes congenital cystic adenomatoid malformation, bronchopulmonary sequestration, and congenital lobar emphysema, has been reported to increase the risk of recurrent respiratory infection. In particular, respiratory syncytial virus (RSV) causes severe lower respiratory tract disease in high-risk infants. The objective of this study was to investigate the risk of severe RSV infection in infants with CCLD. METHODS: Infants antenatally diagnosed as having CCLD and admitted to a neonatal intensive care unit at the National Center for Child Health and Development in Tokyo between September 2002 and October 2011 were included in this study. We investigated retrospectively whether the infants were hospitalized with RSV infection by 24 months of age using their medical records. RESULTS: Forty-eight infants were antenatally diagnosed as having CCLD. Of the 48 infants, four (8.3%) were hospitalized with RSV infection by 24 months of age. CONCLUSIONS: Infants with CCLD have increased risk of severe RSV infection.

Extracorporeal membrane oxygenation for congenital diaphragmatic hernia in Japan.

BACKGROUND: The aim of this study was to clarify how extracorporeal membrane oxygenation (ECMO) is used to treat congenital diaphragmatic hernia (CDH) in Japan. METHODS: We completed a nationwide survey of CDH involving 614 infants. The subjects included 43 patients who underwent ECMO. We compared the clinical data of the patients who did and did not survive ≥ 90 days, and analyzed the 24 h blood gas data in isolated CDH cases in both groups. RESULTS: Of the 43 CDH patients, non-isolated CDH associated with other life-threatening or chromosomal anomalies was diagnosed in six patients. Only one of these six patients was able to discontinue ECMO and survived, and the other five died shortly after birth. The other 37 patients all had isolated CDH. The reason for initiating ECMO in 31 of these patients was persistent pulmonary hypertension of the newborn (PPHN). In the 37 patients with isolated CDH, ECMO was initiated within 24 h after birth. Sixteen patients (37%) survived ≥ 90 days, and intact discharge was possible in eight cases. Among the isolated CDH patients, on ROC analysis of the lowest oxygenation index (OI) to predict 90 day survival, the cut-off was 15. CONCLUSIONS: ECMO is used to treat PPHN starting from an early period after birth, but the mortality and morbidity are not favorable. For lowest OI, the index used to predict survival following ECMO, the cut-off was 15.

The lung to thorax transverse area ratio has a linear correlation with the observed to expected lung area to head circumference ratio in fetuses with congenital diaphragmatic hernias.

BACKGROUND/PURPOSE: The purpose of this study was to clarify the relationship between the lung to thorax transverse area ratio (L/T ratio) and the observed to expected lung area to head circumference ratio (O/E LHR), based on the results of a nationwide Japanese survey conducted in 2011, and to evaluate the compatibility of these prognostic predictors of fetal CDH. METHODS: Two hundred and forty-two prenatally diagnosed isolated CDH patients born between 2006 and 2010 were included in the present analysis. A regression analysis was conducted to investigate the relationship between the L/T ratio and the O/E LHR based on 191 simultaneous measurements of these parameters in 120 patients. RESULTS: The linear regression equation between the L/T ratio and the O/E LHR was: L/T ratio=0.0233+(0.00222×O/E LHR), (R=0.847, p<0.0001). According to this equation, 25% of the O/E LHR, the cut-off value used in the fetal intervention for CDH, was equivalent to an L/T ratio of 0.08, a commonly accepted cut-off value for identifying the most severe cases of fetal CDH. CONCLUSIONS: As there is a positive correlation between the L/T ratio and the O/E LHR, these two parameters proved to be used interchangeably according to the linear regression equation.

Poly(lactic acid) microparticles coated with insulin-containing layer-by-layer films and their pH-dependent insulin release.

Poly(lactic acid) (PLA) microparticles were coated with layer-by-layer (LbL) films containing insulin and the pH-dependent release of insulin was studied. The LbL films were prepared on the surface of PLA microparticles by the alternate deposition of insulin and poly(allylamine hydrochloride) (PAH) through the electrostatic attraction between insulin and PAH. The insulin loading on the PLA microparticles depended on the film thickness, which corresponded to the number of insulin layers, and on the pH of the solution used to deposit insulin. The insulin loading increased with the film thickness and when the film was prepared at pH 7.4. The LbL films decomposed upon exposure to acidic solutions because the electrostatic attraction between the insulin and the PAH in the films disappeared when the charge on insulin changed from negative to positive at an acidic pH, which resulted in the release of insulin. The temperature and salt concentration did not affect the pH stability of the LbL films. The pH threshold for insulin release was pH 5.0-6.0, which corresponds to isoelectric point of insulin, 5.4. The release of insulin from the microparticles was rapid, and was almost complete within a few minutes. The circular dichroism spectra showed that the released insulin retained its original secondary structure. Our insulin-loaded PLA microparticles may be useful for the controlled release of insulin.

Outcome of congenital diaphragmatic hernia with indication for Fontan procedure.

BACKGROUND: The aim of this study was to clarify the outcome of patients with cardiovascular malformation (CVM) among those with congenital diaphragmatic hernia (CDH) who are indicated for the Fontan procedure. METHODS: The subjects included 76 CDH patients with CVM recruited from a national survey of 614 CDH patients. The outcomes were evaluated between two groups divided according to indication for the Fontan procedure. Patients with functional univentricular disease were considered to be candidates for the Fontan procedure. RESULTS: Sixteen (21.1%) of the 76 patients were candidates for the Fontan procedure, accounting for 2.6% of all 614 patients with CDH. None of these patients, however, underwent the Fontan procedure. Among the 16 patients, the absence of obstruction of the left ventricular outflow tract (LVOTO) was significantly associated with better 90 day survival (71.4%, 5/7, for those without LVOTO vs 0.0%, 0/9, for those with LVOTO, P = 0.0007). After excluding 22 patients with chromosomal and/or genetic abnormalities or syndromes, the 90 day survival rate was significantly better in neonates without than with indication for the Fontan procedure (62.5%, 25/40 vs 28.6%, 4/14, P = 0.0271). CONCLUSIONS: Patients with indications for the Fontan procedure are rare, and the outcome of patients with LVOTO among those with CDH is especially poor.

Pneumothoraces as a fatal complication of congenital diaphragmatic hernia in the era of gentle ventilation.

INTRODUCTION: Pneumothorax remains a life-threatening complication that occurs in congenital diaphragmatic hernia (CDH), even under respiratory management with gentle ventilation. The aim of this study was to evaluate the prevalence of pneumothoraces as a fatal complication during the management of CDH based on the results of a nationwide Japanese survey conducted in the era of gentle ventilation. MATERIALS AND METHODS: A retrospective cohort study was performed as part of a nationwide Japanese survey of CDH. A total of 510 neonates with isolated CDH born between 2006 and 2010 were included in this study. The patients were divided into four groups according to operative findings related to the diaphragmatic defect size and operability, which represents the disease severity: defects less than 25%, defects more than 25% but less than 75%, defects more than 75%, and a patient group that was unable to undergo surgery. The prevalence of pneumothorax and the survival rate were compared with respect to each disease severity group. Each case was evaluated to determine whether the development of a pneumothorax was the primary cause of death. RESULTS: Of the 510 neonates with isolated CDH, 69 patients developed a pneumothorax before and/or after surgical intervention. Of the 69 patients 38 patients died, and only 26 patients were discharged from the hospital without any major morbidity that requires home treatment ("intact discharge"). The prevalence of pneumothorax increased and the survival rate and intact discharge rate decreased as the severity of the disease worsened. The number of patients whose pneumothorax was presumed to be the primary cause of death also increased as the severity of the disease worsened. The survival rate of the patients with pneumothorax was significantly lower than that of the patients without pneumothorax among the groups with 25 to 75% defects and 75% or more defects. CONCLUSIONS: Pneumothoraces was found to more likely occur in neonates with CDH associated with a large defect of the diaphragm. The survival rate and intact discharge rate decreased as the severity of the disease worsened, especially among the patients who developed pneumothorax accompanied by large diaphragmatic defects. No other risk factors related to pneumothorax occurrence were found, except for the severity of the disease itself, thus suggesting that pneumothorax was associated with a lethal outcome in neonates with CDH associated with a large defect of the diaphragm.

Electrochemical biosensors based on ferroceneboronic Acid and its derivatives: a review.

We review recent progress in the development of electrochemical biosensors based on ferroceneboronic acid (FcBA) and ferrocene (Fc)-modified boronic acids. These compounds can be used to construct electrochemical biosensors because they consist of a binding site (i.e., a boronic acid moiety) and an electrochemically active part (i.e., an Fc residue). By taking advantage of the unique properties of FcBA and its derivatives, electrochemical sensors sensitive to sugars, glycated hemoglobin (HbA1c), fluoride (F(-)) ions, and so forth have been widely studied. FcBA-based sugar sensors rely on the selective binding of FcBA to 1,2- or 1,3-diol residues of sugars through the formation of cyclic boronate ester bonds. The redox properties of FcBA-sugar adduct differ from those of free FcBA, which forms the basis of the electrochemical determination of sugars. Thus, non-enzymatic glucose sensors are now being actively studied using FcBA and Fc-modified boronic acids as redox markers. Using a similar principle, HbA1c can be detected by FcBA-based electrochemical systems because it contains hydrocarbon chains on the polypeptide chain. HbA1c sensors are useful for monitoring blood glucose levels over the preceding 8-12 weeks. In addition, FcBA and Fc-modified boronic acids have been used for the detection of F(-) ions due to the selective binding of boronic acid to F(-) ions. F(-)-ion sensors may be useful alternatives to conventional ion-selective electrodes sensitive to F(-) ion. Furthermore, FcBA derivatives have been studied to construct lectin; steroids; nucleotides; salicylic acid; and bacteria sensors. One of the limitations of FcBA-based sensors comes from the fact that FcBA derivatives are added in sample solutions as reagents. FcBA derivatives should be immobilized on the surface of electrodes for developing reagentless sensors.

Layer-by-layer deposited nano- and micro-assemblies for insulin delivery: a review.

We present an overview of the recent progress in the development of layer-by-layer (LbL) assembled thin films and microcapsules for insulin delivery. The LbL deposition of insulin-containing thin films on the surfaces of flat substrates or microparticles has been investigated for orally administered insulin formulations. The amount of insulin in the LbL films can be precisely controlled by altering the number of layers in the films. As-prepared LbL films and microcapsules can be loaded with insulin by exposing the films and microcapsules to an insulin solution. The insulin can be released by pH-induced decomposition or permeability changes in the LbL films and microcapsules. Closed-loop insulin delivery systems that can release insulin in response to changes in glucose concentration have also been constructed with LbL films and microcapsules. Glucose-sensitive materials, such as glucose oxidase, concanavalin A, and phenylboronic acid, have been incorporated into insulin-containing LbL assemblies. In addition, LbL film-coated pancreatic islet cells have recently been developed as a bio-artificial pancreas, in which the islet cells are isolated from the recipient's immune system by the LbL coatings. Thus, LbL films and microcapsules could make a significant contribution to the further development of patient-friendly insulin delivery systems.