Short-Term HRV Detection and Human Fatigue State Analysis Based on Optical Fiber Sensing Technology.

Mental fatigue is a key cause of chronic diseases and traffic accidents, which is difficult to be quantitatively evaluated. In order to non-intrusively detect fatigue state, an optical fiber sensing system is proposed, which is non-invasive and does not require direct contact with skin. The fiber sensor was fabricated through phase mask exposure method and packaged by sensitivity-enhanced structure, which can suppress transverse force and increase signal amplitude by 5%. A fatigue-inducing experiment was carried out, and the heartbeat signals of 20 subjects under different fatigue states were collected by the proposed sensing system. A series of heart rate variability indicators were calculated from the sensing signals, and their statistical significance for fatigue was analyzed. The experiment results showed that the values of SDNN and LF/HF increased significantly with subjects' fatigue level. This study shows that the proposed fiber optic sensing system has practical value in fatigue state monitoring.

Glucose-Responsive Polyelectrolyte Complexes Based on Dendritic Mesoporous Silica for Oral Insulin Delivery.

The postprandial glycemic regulation is essential for diabetic patients to reduce the risk of long-term microvascular and macrovascular complications. Herein, we designed a glucose-responsive oral insulin delivery system based on polyelectrolyte complexes (PECs) for controlling the increasing postprandial glucose concentrations. Briefly, alginate-g-3-aminophenylboronic acid (ALG-g-APBA) and chitosan-g-3-fluoro-4-carboxyphenylboronic acid (CS-g-FPBA) were wrapped on mesoporous silica (MSN) to form the negative charged ALG-g-APBA@MSN and the positive charged CS-g-FPBA@MSN nanoparticles, with an optimum insulin loading capacity of 124 mg/g and 295 mg/g, respectively. ALG-g-APBA@MSN was further cross-linked with CS-g-FPBA@MSN to form PECs through electrostatic interaction and borate esters. The dense polyelectrolyte network wrapped on MSN was capable of preventing insulin from diffusion and regulating its release. The in vitro insulin release of PECs demonstrated an obvious glucose response profile in different glucose concentrations (0 mg/mL, 2 mg/mL, 5 mg/mL) and presented a switch "on" and "off" release regulation at hyperglycemic or normal state. The CCK-8 assay showed that none of the MSN, ALG-g-APBA@MSN, CS-g-FPBA@MSN, and PECs possessed cytotoxicity to Caco-2 cells. For in vivo tests, the oral PECs exhibited a significant hypoglycemic effect and maintained in the euglycemic levels up to approximately 12 h on diabetic rats. Overall, the PECs directly triggered by postprandial glucose in the intestine have a good potential to be applied in intelligent insulin delivery by the oral route.

Nanoscale cationic micelles of amphiphilic copolymers based on star-shaped PLGA and PEI cross-linked PEG for protein delivery application.

To enhance the bioavailability of protein therapeutants and improve the stability of storage and delivery, a series of branched amphiphilic block copolymers consisting of cholic acid (CA) initiated poly(D,L-lactide-co-glycolide) (CA-PLGA) and water-soluble polyethyleneimine cross-linked polyethylene glycol (PEI-PEG) denoted as CA-PLGA-b-(PEI-PEG) were synthesized and characterized. CA-PLGA-b-(PEI-PEG) presented low cytotoxicity by MTT and cck-8 assay. The cationic CA-PLGA-b-(PEI-PEG) micelles (diameter about 100 nm and zeta potential 34-61 mV) were prepared through self-assembly method, and complexed with insulin via electrostatic interaction to obtain nanoscale micelle/insulin complexes. The micelle/insulin complexes-loaded CA-PLGA microspheres (MIC-MS, 10.4 ± 3.85 µm) were manufactured by employing a double emulsion (W1/O/W2) method. The in vitro insulin release behavior and in vivo hypoglycaemic effect of MIC-MS on streptozotocin (STZ) induced diabetic rats were compared with those of the insulin-loaded CA-PLGA microspheres (INS-MS, 7.8 ± 2.57 µm). The initial burst in vitro release of MIC-MS was markedly lower than that of INS-MS (P < 0.01), and the pharmacological availability of MIC-MS via subcutaneous administration was 148.9% relative to INS-MS. Therefore, the cationic CA-PLGA-b-(PEI-PEG) micelles can effectively increase the bioavailability of insulin in CA-PLGA microspheres and can be considered as a potential protein carrier.

Self-assembly pH-sensitive chitosan/alginate coated polyelectrolyte complexes for oral delivery of insulin.

Polyelectrolyte complexes (PEC) provide new opportunities for controlled release system of drugs, and have potentials to address challenges on the way to effective oral insulin delivery. Here, an innovative pH-sensitive PEC for insulin oral administration was developed, which was formed by self-assembly of two oppositely charged nanoparticles (chitosan-coated nanoparticles and alginate-coated nanoparticles) through electrostatic interaction via optimised double emulsion method. The encapsulation efficiency of insulin-loaded alginate-coated and chitosan-coated nanoparticles were 81.5 ± 7.4% and 55.2 ± 7.0%, respectively, and the particle size of these nanoparticles were in 200-300 nm range. The pH-dependent morphology of PEC was observed by transmission electron microscopy. The PEC exhibited insulin release profile triggered by pH in vitro and was non-cytotoxicity against Caco-2 cell. The insulin-loaded PEC could decrease blood glucose levels effectively and prolong insulin release after oral administration to diabetic rats. The results illustrated that the as-prepared PEC may be employed as a potential oral insulin delivery system.

Multifunctional and multimodality theranostic nanomedicine for enhanced phototherapy.

Photodynamic therapy (PDT) has attracted much attention in recent years for its favorable therapeutic efficacy in cancer therapy. However, PDT alone is insufficient to improve the therapeutic efficiency mainly due to the limited penetration depth of light, the insufficient O2 supply in the hypoxic microenvironment, and the high level of reducing substances in cancer cells. To overcome these limitations, a multifunctional MnO2 nanoparticle was constructed with honeycomb MnO2 which was loaded with the photosensitizer Ce6 and modified with polydopamine on its surface (HMnO2/C&P) to achieve efficient PDT/mild photothermal treatment (PTT) combination therapy. HMnO2/C&P had high drug loading contents (11.2% Ce6) and can be responsive to the tumor microenvironment (TME), supply O2 to alleviate the hypoxic microenvironment, and clear GSH to reduce the consumption of ROS, thus enhancing the PDT effect. The introduction of PDA can improve the stability of HMnO2/C&P, and further give the ability of PTT to act as nanomedicine. The results of in vitro and in vivo experiments show that HMnO2/C&P based PDT/mild PTT combination therapy has an excellent inhibitory effect on tumor growth. Meanwhile, HMnO2/C&P can act as a fluorescence imaging reagent and a TME triggerable magnetic resonance imaging (MRI) contrast agent, thus having excellent multimodal self-tracking abilities. Collectively, this study provides a new perspective on the design of multifunctional theranostic nanomedicine to maximize the efficacy of cancer phototherapy.

Chemoselective modification of turnip yellow mosaic virus by Cu(I) catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction and its application in cell binding.

Turnip yellow mosaic virus (TYMV) is an icosahedral plant virus with a diameter of 28-30 nm that can be isolated in gram quantities from turnip or Chinese cabbage inexpensively. In this study, TYMV combined with spatially addressable surface chemistries was selected as a prototype bionanoparticle for modulating patterns of cell adhesion, morphology, and proliferation. We exploited the chemical reactivity of TYMV using the mild conditions of Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction, the best example of "click" chemistry. Oligo-ethylene glycol (OEG) short chain, coumarintriazole, and RGD-containing peptide were grafted on the surface of TYMV via carbodiimide activation and CuAAC reaction. The bioconjugation to intact viral particles was confirmed by MS, TEM, FPLC, and SDS-PAGE with fluorescence visualization analysis. Therefore, this method is a generally useful means of incorporating various types of functionalities onto the TYMV surface. Further studies were done to learn the behavior of NIH-3T3 fibroblast cells on the modified or unmodified TYMV surfaces. OEG-modified TYMV surfaces retarded cell attachment and growth, while cell adhesion, spreading, and proliferation were dramatically enhanced on RGD-modified TYMV surfaces. Compared with RGD immobilized 3-aminopropyltriethoxysilane-coated glass surface, the cells are more ready to spread fully and proliferate on TYMV-RGD coated surface, which thus provides a more cell-friendly environment with nanometer-scale surface features. This illustrates the potential application of plant virus based materials in tissue engineering, drug delivery, and biosensing.

Fabrication and characterization of a novel semi-interpenetrating network hydrogel based on sodium carboxymethyl cellulose and poly(methacrylic acid) for oral insulin delivery.

In this research, pH-sensitive semi-interpenetrating polymer network hydrogels based on sodium carboxymethyl cellulose and poly(methacrylic acid) were synthesized using free radical polymerization and semi-interpenetrating polymer network approach for oral administration of insulin. The chemical structure and thermal stability of the hydrogels were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis measurements. The interior morphology was observed by scanning electron microscopy and the inner structure exhibited a porous honeycomb-like shape. The investigations on the swelling properties of hydrogels revealed their ability to response to pH value change. The in vitro release behavior of insulin was pH dependent and the release of insulin was much lower at pH 1.2 compared to pH 6.8. In vitro cytotoxicity assay indicated that the hydrogels were noncytotoxic to HeLa cells. A sustained reduction in blood glucose level was observed after oral administration of insulin-loaded hydrogel to diabetic rats at 75 IU/kg. These results indicated that the hydrogel would be a promising vehicle for oral insulin delivery systems.

Characterization of horse spleen apoferritin reactive lysines by MALDI-TOF mass spectrometry combined with enzymatic digestion.

Ferritins are a class of iron storage protein spheres found mainly in the liver and spleen, which have attracted many research interests due to their unique structural features and biological properties. Recently, ferritin and apoferritin (ferritin devoid of the iron core), have been employed as chemically addressable nanoscale building blocks for functional materials development. However, the reactive residues of apoferritin or ferritin have never been specified and it is still unclear about the chemoselectivity of apoferritin towards different kinds of bioconjugation reagents. In this work, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry combined with enzymatic digestion analysis was used to identify the reactive lysine residues of horse spleen apoferritin when conjugated with N-hydroxysuccinimide reagents. The result demonstrated that among all the lysine residues, K97, K83, K104, K67 and K143 are the reactive ones that can be addressed.

[Synthesis of amphiphilic block copolymer of PLGA-b-(PEI-co-PEG) and characterization of the self-assembled cationic micelles].

OBJECTIVE: To synthesize a biodegradable and minimally cytotoxic amphiphilic block copolymer of PLGA-b-(PEI-co- PEG) and study its micellization behavior. METHODS: PLGA was synthesized by ring-opening polymerization. The cross-linked copolymer of PEI-co-PEG was synthesized from the low-molecular-weight polyethyleneimine (PEI, 1800 D) and hydrophilic poly(ethylene glycol) (PEG, 2000 D). PLGA-b-(PEI-co-PEG) was synthesized by dehydration condensation reaction of PLGA and water soluble PEI-co-PEG. The biodegradability of PEI-co-PEG was evaluated according to the molecular weight change after incubation at 37 ℃ for different time. The cytotoxicity of PLGA- b-(PEI-co-PEG) and PEI-co-PEG in MCF-7 cells was determined by MTT assay. The cationic PLGA-b-(PEI-co-PEG) micelles were prepared by standard dialysis method. The particle size and Zeta potential of the micelles were measured by a Malvern laser particle size analyzer. Micelle/insulin complexes were prepared by simple mixing method and their morphology were characterized by transmission electron microscopy (TEM). The fluorescence quenching method was used to determine the stability of the micelle/insulin complexes at different salt concentrations. RESULTS: Amphiphilic block copolymer of PLGA-b-(PEI-co-PEG) was successfully synthesized. The half-life of PEI-co-PEG degradation in PBS at 37 ℃ was about 48 h. The 50% cell inhibiting concentration (IC50) of PLGA-b-(PEIco- PEG) and PEI-co-PEG in MCF-7 cells were 1375.7 µg/mL and 425.1 µg/mL, respectively. The micelles of PLGA-b-(PEI-co- PEG) (particle size: 99.5±2.61 nm, Zeta potential: 52.9±2.38 mV) were complexed with insulin via electrostatic interaction and formed nanoscale micelle/insulin complexes. The dissociation rate of micelle/insulin complexes in 150 mmol/L NaCl solution was 27.6%. CONCLUSIONS: The synthesized PEI-co-PEG shows good degradability in vitro. The cytotoxicity of PLGA-b-(PEI-co- PEG) is significantly lower than PEI-co-PEG, and PLGA-b-(PEI-co-PEG) micelle/insulin complexes have good salt- resistant stability in physiological condition.

Chemoselective derivatization of a bionanoparticle by click reaction and ATRP reaction.

Horse spleen apoferritin, the hollow protein shell derived from ferritin, a special biological nanoparticle, can be chemoselectively modified at the lysine residues, which affords a robust scaffold for further chemical reactions including Cu(i)-catalyzed azide-alkyne cycloaddition reaction and atom transfer radical polymerization reaction.

[Preparation of nanoparticles for sustained insulin release using poly (ethylene glycol) -poly (ε-caprolactone)-poly (N, N-diethylamino-2-ethylmethaerylate)].

OBJECTIVE: To prepare an insulin-loaded nanoparticle assembled using pH-sensitive poly(ethylene glycol)-poly(ε-caprolactone)-poly(N,N-diethylamino-2-ethylmethaerylate) (mPEG-PCL-PDEAEMA) and investigate its performance of sustained insulin release in vitro and its hypoglycemic effects in diabetic rats. METHDOS: mPEG-PCL-PDEAEMA triblock copolymers with different hydrophobic lengths were synthesized by ring opening polymerization (ROP) combined with atom transfer radical polymerization (ATRP). The copolymers were characterized using Fourier-transform Infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance spectroscopy (1H-NMR). Insulin-loaded nanoparticles were prepared by nanoprecipitation technique, in which the reversible swelling of the pH-sensitive material was used for insulin loading and release. The obtained nanoparticles were further confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The entrapment efficiency (EE%), drug loading (DL%) and in vitro release characteristics of the insulin- loaded nanoparticles were assessed using BCA protein assay kit. The hypoglycemic effects of the nanoparticles were evaluated by monitoring the glucose levels. RESULTS: The size of the nanoparticles decreased as pH value increased within the range of 1.2 to 7.4. Using copolymers mPEG5k-PCL13k- PDEAEMA10k and mPEG5k-PCL10k-PDEAEMA10k as the drug carriers, the nanoparticles prepared with an optimal insulin-coplymer mass ratio of 90% had an average size of 181.9∓6.67 nm and 169∓7.1 nm, maximal EE% of (81.99∓1.77)% and (53.12∓0.62)%, and maximal DL% of (42.46∓0.53)% and (32.34∓0.26)%, respectively. Compared with free insulin, the insulin-loaded nanoparticles was capable of sustained insulin release and the release rate was lowered as the hydrophobic length increases. In diabetic rats, the insulin-loaded nanoparticles based on mPEG5k-PCL13k- PDEAEMA10k maintained a sustained hypoglycemic effect for 48 h, which was significantly longer than the time of free insulin. CONCLUSION: The pH-sensitive triblock copolymer mPEG-PCL-PDEAEMA can serve as a promising candidate of carrier for sustained release of insulin.

Delivery of curcumin by directed self-assembled micelles enhances therapeutic treatment of non-small-cell lung cancer.

BACKGROUND: It has been widely reported that curcumin (CUR) exhibits anticancer activity and triggers the apoptosis of human A549 non-small-cell lung cancer (NSCLC) cells. However, its application is limited owing to its poor solubility and bioavailability. Therefore, there is an urgent need to develop a new CUR formulation with higher water solubility and better biocompatibility for clinical application in the future. MATERIALS AND METHODS: In this study, CUR-loaded methoxy polyethylene glycol-polylactide (CUR/mPEG-PLA) polymeric micelles were prepared by a thin-film hydration method. Their characteristics and antitumor effects were evaluated subsequently. RESULTS: The average size of CUR/mPEG-PLA micelles was 34.9±2.1 nm with its polydispersity index (PDI) in the range of 0.067-0.168. The encapsulation efficiency and drug loading were 90.2%±0.78% and 9.1%±0.07%, respectively. CUR was constantly released from the CUR/mPEG-PLA micelles, and its cellular uptake in A549 cells was significantly increased. It was also found that CUR/mPEG-PLA micelles inhibited A549 cell proliferation, increased the cell cytotoxicity, induced G2/M stage arrest and promoted cell apoptosis. Moreover, the CUR/mPEG-PLA micelles suppressed the migration and invasion of A549 cells more obviously than free CUR. Additionally, CUR/mPEG-PLA micelles inhibited human umbilical vein endothelial cells migration, invasion and corresponding tube formation, implying the antiangiogenesis ability. Its enhanced antitumor mechanism may be related to the reduced expression of vascular endothelial growth factor, matrix metalloproteinase (MMP)-2, MMP-9 and Bcl-2 as well as the increased expression of Bax. CONCLUSION: The mPEG-PLA copolymer micelles can serve as an efficient carrier for CUR. The CUR/mPEG-PLA micelles have promising clinical potential in treating NSCLC.

[Evaluation of in vitro insulin release from nanoparticles assembled by polyethylene glycol, polycaprolactone and polyethyleneimine].

OBJECTIVE: To prepare insulin-loaded polymeric nanoparticles based on polyethyleneimine-polycaprolactone- polyethylene glycol-polycaprolactone-polyethyleneimine pentablock copolymers and evaluate its in vitro release of insulin. METHODS: Polycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) triblock copolymer was synthesized by ring-opening polymerization method, and the pentablock copolymer was prepared by Michael addition reaction. The copolymers obtained were characterized by Fourier-transform infrared (FT-IR) spectroscopy and (1)H-NMR and their critical aggregation concentration (CAC) was measured by fluorescence technique with pyrene as the probe. Insulin-loaded polymeric nanoparticles based on the pentablock copolymers were prepared by solvent evaporation method that exploited the cationic nature of PEI-PCL-PEG-PCL-PEI to allow the formation of ionic complexes with anionic biomolecules such as insulin. The prepared nanoparticles were further characterized by Malvern laser particle sizer and transmittion electron microscopy (TEM). The drug loading, encapsulation efficiency and in vitro release profile of the nanoparticles were analyzed using Bradford method. RESULTS: Using copolymer PEI10K-PCL4K-PEG2K-PCL4K-PEI10K as the drug carrier, the spherical nanoparticles prepared with an optimal insulin-coplymer mass ratio of 40% allowed the maximum insulin loading of (18.63∓0.07)% and had an average particle size of 175.30∓19.51 nm. The prepared nanoparticles was capable of sustained release of insulin for as long as 48 h in vitro, and the burst release could be minimized by incorporation of PEI in the triblock copolymer. CONCLUSION: The insulin-loaded polymeric nanoparticles based on the pentablock copolymers allow sustained release of insulin in vitro, and PEI can enhance sustained drug release and reduce burst drug release.

Properties of several glycidyl methacrylate-triallyl isocyanurate based affinity adsorbents for removing circulating immune complexes.

Biocompatible affinity adsorbents prepared from macroporous glycidyl methacrylate-triallyl isocyanurate copolymer (GT) has been used for removing circulating immune complexes (CICs). In this work, adsorption of circulating immune complexes on GT-based affinity adsorbents has been studied by using batch and hemoperfusion studies. In batch mode, the equilibrium adsorption level was determined to be a function of the contact time, temperature, initial CIC concentration and adsorbent dosage. In animal hemoperfusion trials, removal of CICs is efficient and rapid. IgG, IgM and complement C3, C4 are minimally affected. There are negligible decreases in RBC, WBC, PLT and HB. Acid-base equilibrium, electrolytes and plasma proteins also are minimally affected.

Cucumber mosaic virus as drug delivery vehicle for doxorubicin.

Taking advantage of the unique structure feature of cucumber mosaic virus (CMV), we have anchored folic acid (FA) as targeting moiety on the rigid CMV capsid and loaded significant amount of doxorubicin (Dox) into the interior cavity of CMV through the formation of Dox-RNA conjugate to provide a nanosized control delivery system for cancer therapy. The FA-CMV-Dox assemblies were characterized using transmission electron microscopy and size exclusion chromatography, which disclose that they have comparable size and morphology to the native CMV particles. The Dox-loaded viral particles exhibit sustained in vitro Dox release profile over 5 days at physiological pH but can be liberated from the conjugates with the presence of elevated level of RNase. The in vitro effects of folate receptor (FR)-targeted CMV-Dox nanoconjugates on cellular internalization and cell proliferation were evaluated by live-cell imaging, MTT and TUNEL assay, respectively, in mouse cardiomyocytes and FR over expression OVCAR-3 tumor cells. The in vivo efficacy was also investigated in the OVCAR-3 BALB/c nude mouse xenograft model through histological alterations and TUNEL assessment. The FA-CMV-Dox particles significantly decrease the accumulation of Dox in the nuclei of mouse myocardial cells and improve the uptake of Dox in the ovarian cancer, leading to less cardiotoxicity and enhanced antitumor effect. We believe that CMV offers a new way to fabricate nanosized drug delivery vehicles.