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Highlights • A rapid-prototyping angle-scanning Surface plasmon resonance was presented. • FDM 3D printing technology was utilized to realize rapid prototyping and cost down manufacture. • Aptasensor was utilized to detect glycated hemoglobin (HbA1c) directly. • The linear detection response of HbA1c appeared in the range from 18 to 147 nM with a detection limit of 1 nM. Abstract Diabetes mellitus is one of the most common noncommunicable diseases in the world. Fasting blood glucose level is one of the diabetes diagnostic criteria, but it is readily affected by stress, exercise and many other factors. Glycated hemoglobin (HbA1c) is an important clinical index for diabetes and related diseases. In this study, a cheaper, rapid-prototyping, high-sensitivity angle-scanning surface plasmon resonance (SPR) was developed by fused deposition modeling (FDM) 3D printing technology for HbA1c detection. The sensor chip is based on an aptamer that has high affinity and high specificity to HbA1c. The results showed that this HbA1c-specific aptamer had high specificity for HbA1c, and the calculated K D was 6.13 × 10−8 M. The linear detection response of HbA1c appeared in the range of 18–147 nM, with a detection limit of 1 nM. This SPR HbA1c detection system could be a promising platform for developing clinical point-of-care diagnostic applications. [ABSTRACT FROM AUTHOR]

Cartilage tissue engineering involves the invention of novel implantable cartilage replacement materials to help heal cartilage injuries that do not heal themselves, aiming to overcome the shortcomings of current clinical cartilage treatments. Chitosan has been widely used in cartilage tissue engineering because of its similar structure to glycine aminoglycan, which is widely distributed in connective tissues. The molecular weight, as an important structural parameter of chitosan, affects not only the method of chitosan composite scaffold preparation but also the effect on cartilage tissue healing. Thus, this review identifies methods for the preparation of chitosan composite scaffolds with low, medium and high molecular weights, as well as a range of chitosan molecular weights appropriate for cartilage tissue repair, by summarizing the application of different molecular weights of chitosan in cartilage repair in recent years. [ABSTRACT FROM AUTHOR]

After tendon-repair surgery, adhesion between the surgical tendon and the synovial sheath is often presented resulting in poor functional repair of the tendon. This may be prevented using a commercially available mechanical barrier implant, Seprafilm, which is composed of hyaluronan (HA) and carboxymethyl cellulose hydrogels. In a rat model, prepared membranes of various compositions of gellan gum (GG), xanthan gum (XG) and HA as well as Seprafilm were wrapped around repaired tendons and the adhesion of the tendons was examined grossly and histologically after 3 weeks of healing. Certain formulations of the XG/GG/HA hydrogel membranes reduced tendon adhesion with equal efficacy but without reducing the tendon strength compared to Seprafilm. The designed membranes swelled rapidly and blanketed onto the tendon tissue more readily and closely than Seprafilm. Also they degraded slowly, which allowed the membranes to function as barriers for extended periods. [ABSTRACT FROM AUTHOR]

Volvox sphere is a bio-mimicking concept of an innovative biomaterial structure of a sphere that contains smaller microspheres which then encapsulate chemicals, drugs and/or cells. The volvox spheres were produced via a high-voltage electrostatic field system, using alginate as the primary material. Encapsulated materials tested in this study include staining dyes, nuclear fast red and trypan blue, and model drugs, bovine serum albumin (BSA) and cytochrome c (CytC). The external morphology of the volvox spheres was observed via electron microscopy whereas the internal structure of the volvox spheres was observed via an optical microscope with the aid of the staining dyes, since alginate is colorless and transparent. The diameter of the microspheres was about 200 to 300μm, whereas the diameter of the volvox spheres was about 1500μm. Volvox spheres were durable, retaining about 95% of their mass after 4weeks. Factors affecting entrapment efficiency, such as temperature and concentration of the bivalent cross-linker, were compared followed by a 7-day in vitro release study. The encapsulation efficiency of CytC within the microspheres was higher at cold (~4°C) and warm (~50°C) temperatures whereas temperature has no obvious effect on the BSA encapsulation. High crosslinking concentration (25% w/v) of calcium chloride has resulted higher entrapment efficiency for BSA but not for CytC. Furthermore, volvox spheres showed a different release pattern of BSA and CytC when compared to microspheres encapsulating BSA and CytC. Despite the fact that the mechanisms behind remain unclear and further investigation is required, this study demonstrates the potential of the volvox spheres for drug delivery. [ABSTRACT FROM AUTHOR]

The articular cartilage disorder at the junction mainly results from constantly repeated dynamic tension/compression effects with ageing and lack of intrinsic defect repairability. Therefore, the degradable piezoelectric scaffolds are very essential, which mimics the dynamic mechanical loading and optimizes the chondrocyte differentiation during the degradation. Here, a degradable aligned electrospun poly- L -lactic acid (PLLA) modified with graphene (rGO) and polydopamine (PDA) fibrous scaffolds with different orientations (0°, 90°) and surface morphologies (wrinkled and porous) was developed as a biocompatible and degradable piezoelectric scaffold with the self-powered tunable piezoelectricity to modulate cell behaviour and cell differentiation by tuning the degradation effect. The results show that the electrical output and mechanical properties of the composite fibrous scaffold can be improved by adding rGO and applying mechanical force along with the 90° orientation. With changing the degradation behavior, dynamic mechanical loading on the porous PLLA/rGO/PDA fibrous scaffold exhibits a significant increase in cell proliferation and secretion of extracellular matrix (ECM). More surprisingly, as extending the degradation periods to 21 days, a higher glycosaminoglycans (GAGs) synthesis was detected in prechondrogenic ATDC5 cells cultured on the degraded porous scaffold compared with that after 7 days' culture. This indicated that long-term degradation favoured promoting cell differentiation of ATDC5 towards a chondrogenic phenotype due to dynamic mechanical loading, low-intensity electrical stimulation, and interconnected porous structural morphology. In contrast, on the wrinkled PLLA/rGO/PDA fibre with a high-intensity electrical stimulation, the ALP activity significantly increased after 21 days, inducing mineralization with the differentiation of ATDC5 into osteocytes. The modulation of the degraded environment and electrical stimulation of the piezoelectric scaffold offers an effective alternative to influence cell functions, significantly improving the ECM secretion and cell differentiation. [Display omitted] • The modulation of cell functions has been demonstrated by the biocompatible and biodegradable PLLA/rGO/PDA scaffold. • The piezoelectricity generated from the bending of the scaffold can help to increase the secretion of extracellular matrix. • Structure orientation, surface morphology and degradation effect of the scaffold on cell behaviors have been Investigated. • The piezoelectric and mechanical properties of the scaffold control the cell proliferation and differentiation progresses. • The scaffold can provide self-powered electrical stimulation from human motions to recover the damaged cartilage. [ABSTRACT FROM AUTHOR]

Abstract: The insertion of dental filling into the dental cavity is a common method of maintaining the space and shape of dental cavities after dental extractions. To develop novel dental fillings meeting clinical requirements, gellan gum (GG) is selected in this study to prepare fillings with specific characteristics by modulating gellan gum concentrations (denoted as GG-DF). The results indicate that the microstructure, porosity, and compression modulus of 1.5% and 1.75% GG-DF are similar to a commercially product (Teruplug®) and with good blood absorption capacity. The degradation ratio of Teruplug® in an amylase/phosphate buffer solution after 4weeks is 80% whereas that of 1.5% and 1.75% GG-DF is 65%. Cell migration studies confirmed that the migration ability of fibroblast was significantly inhibited by gellan gum. These results demonstrate that 1.5% and 1.75% GG-DF are potentially viable for developing into dental fillings. [Copyright &y& Elsevier]

Abstract: The aim of this study was to prepare and evaluate chitosan dressings treated with sodium hydroxide (NaOH) and/or sodium tripolyphosphate (Na5P3O10) for haemostatic use. The pure sodium hydroxide-gelled chitosan dressing (CS-B) had water contents (about 95%) and porosities (about 85%) which were similar to those of commercially available chitosan-based products. The CS-B dressing also exhibited homogeneously sized and penetrating pores throughout, whereas the commercially available Clo-Sur PAD showed porous lamellar structures inside and Instant Clot Pad exhibited a heterogeneous pore size distribution. Additionally, the CS-B dressing was flexible and resilient, free of odour and able to recover completely after compression in a hydrated state. Finally, the CS-B sponge absorbed blood quickly, accelerating blood clotting, enhancing red blood cell adhesion and maintaining its original shape after haemostatic testing. [Copyright &y& Elsevier]

Abstract: Collagen II and hyaluronan are the two major components of the native extracellular matrix (ECM). Both biopolymers are responsible for providing the associated tissues with tensile strength, and also serve as a structural scaffold for cell adhesion and growth. Over the years, many researchers have focused on the preparation and evaluation of man-made ECM comprising the two polymers in the form of a membrane for chondrocyte culture applications. Here, a simple and in situ method, involving the injection of the hyaluronan/collagen II (HA/Col II) mixture solution through a pair of hollow-centered parallel disc electrodes (HCPDEs) of a high-voltage electrostatic field system, was developed and employed to prepare HA/Col II microspheres in watery phase. The HA/Col II microspheres were firmed up by a two-step cross-linking treatment (first by FeCl3 and then by 1-ethyl-3-(3-dimethyl aminopropyl) carbodimide, EDC) to secure the spherical structure shape. Then, at 37°C, reconstitution treatment of the Col II molecules was conducted to further strengthen the microspheres. Depending on treatment conditions, the resulting series of HA/Col II microspheres all exhibited good sphericity in the range of 486±43 to 679±24μm in diameter. Furthermore, the ratio and amount of HA/Col II in the mixture solutions would affect the morphological structure and basic characteristics, including mechanical strength, thermal properties and water content. In the preliminary study, the HA/Col II microspheres have shown to provide favorable ECM characteristics, with appropriate mechanical strength, and exhibited a 3D inclination. [Copyright &y& Elsevier]

Wearable glucose sensors have attracted significant attention for enabling non-invasive blood glucose measurement without discomfort and risk of infection. However, it is a challenge to simultaneously realize wearable adaptability, biodegradability, and excellent sensing performance. Herein, a cellulose paper-based non-invasive biosensor relying on reverse iontophoresis was designed to detect glucose in interstitial fluid (ISF), and two different enzyme immobilization strategies have been compared. The results showed inkjet-printed cellulose paper-based biosensor (IPB) performances better than the drop-coated cellulose paper-based biosensor (DPB). IPB has twice response current more than DPB in detection range (0–10 mM). In sensitivity, IPB is 1.170 μA/mM three times higher than the DPB (0.376 μA/mM). Besides, IPB's electron-transfer resistance (Rct) is 7.27 kΩ smaller than DPB (Rct = 10.51 kΩ) about 30 %. More importantly, IPB exhibited a good reproducibility (RSD, 4.82 %), which was much less than DPB (RSD, 18.35 %). Furthermore, the IPB realizes noninvasive continuous glucose monitoring over 6 h in volunteer experiments with great analytical performance comparable to commercial devices (Pearson correlation 0.732). Cellulose paper-based glucose sensors with inkjet printing provide non-invasive access to statistically significant diagnostic information, simple and cost-effective, which promotes the application of flexible, wearable, degradable bioelectrodes in continuous glucose monitoring at home, providing a concept for full integration in a compact and portable way in the future. • A cellulose paper-based wearable glucose sensor exhibits outstanding performance in non-invasive glucose monitoring over 6 h. [ABSTRACT FROM AUTHOR]

• Anti HCT interference blood glucose sensors based on fiber paper-based screen-printed carbon electrode were demonstrated. • The paper-based glucose sensor can reduce HCT interference significantly with HCT range 20% to 70%. • In consensus error grid, 95% of the data points lie within zones A and B. As the number of diabetic patients increases year by year, the demand for a self-monitoring blood glucose test also increases. Additionally, more in-depth studies of blood glucose biosensors have led to increasing accuracy requirements. However, at present, most enzyme glucose sensors have difficulty solving issues related to hematocrit (HCT) interference. Most studies on anti-HCT interference in blood glucose sensing have mainly focused on correction factors, such as glucose correction, and electrical impedance or resistivity characteristics to correct the impact of HCT. In this work, we developed an anti-HCT-interference blood glucose sensor based on a fiber paper-based screen-printed carbon electrode with a mediator (potassium ferricyanide) and glucose oxidase (GOD), which were fixed through inkjet printing. When testing whole blood samples with HCT levels of 20%–70% and a fluid dropping method, the results of a consensus error grid analysis showed that 91% of the data points lied within zones A and B. The glucose sensor was exclusively designed with a 16 μL chamber in the working area of the sensor. When the testing fluid was taken in by capillary sucking, the effect of HCT was further reduced, and 95% of the data points lied within zones A and B in the consensus error grid. [ABSTRACT FROM AUTHOR]

Volvox sphere is a bio-mimicking concept of a biomaterial structure design able to encapsulate chemicals, drugs and/or cells. The aim of this study was to prepare Volvox spheres encapsulating AML12 liver cells and mesenchymal stem cells (MSCs) via a high voltage electrostatic field system. The results demonstrated that AML12 liver cells and MSCs could be successfully encapsulated into the inner spheres and the outer sphere of the Volvox spheres. The improved cell viability of MSCs was achieved by the addition of collagen and polyethylene glycol into the preparation components of the Volvox spheres. Collagen material potentially provides extracellular matrix-like structure for cell adhesion while polyethylene glycol provides a void/loose space for permeability of metabolites. The encapsulated MSCs were able to differentiate into hepatocytes or hepatocyte-like cells and express liver cell markers including albumin, alpha feto-protein and cytokeratin 18. The encapsulated cells secreted albumin to about 140 ng on day 14. Based on these observations, we conclude that Volvox spheres can be used as an alternative approach to encapsulate multiple types of cells, here AML12 hepatocyte cell line and MSCs. Nevertheless, efforts are still needed to improve the viability of the encapsulated cells and increase the differentiation of MSCs into functional liver cells. [ABSTRACT FROM AUTHOR]

Abstract: Using excitation polarization-resolved second harmonic generation (SHG) microscopy, we measured SHG intensity as a function of the excitation polarization angle for type I and type II collagens. We determined the second order susceptibility (χ(2)) tensor ratios of type I and II collagens at each pixel, and displayed the results as images. We found that the χ(2) tensor ratios can be used to distinguish the two types of collagen. In particular, we obtained χ zzz/χ zxx = 1.40 ± 0.04 and χ xzx/χ zxx = 0.53 ± 0.10 for type I collagen from rat tail tendon, and χ zzz/χ zxx = 1.14 ± 0.09 and χ xzx/χ zxx = 0.29 ± 0.11 for type II collagen from rat trachea cartilage. We also applied this methodology on the label-free imaging of engineered cartilage tissue which produces type I and II collagen simultaneously. By displaying the χ(2) tensor ratios in the image format, the variation in the χ(2) tensor ratios can be used as a contrast mechanism for distinguishing type I and II collagens. [Copyright &y& Elsevier]

Although traditional 3D scaffolds or biomimetic hydrogels have been used for tissue engineering and regenerative medicine, soft tissue microenvironment usually has a highly anisotropic structure and a dynamically controllable deformation with various biomolecule distribution. In this study, we developed a hierarchical hybrid gelatin methacrylate-microcapsule hydrogel (HGMH) with Neurotrophin-3(NT-3)-loaded PLGA microcapsules to fabricate anisotropic structure with patterned NT-3 distribution (demonstrated as striped and triangular patterns) by dielectrophoresis (DEP). The HGMH provides a dynamic biomimetic sinuate-microwrinkles change with NT-3 spatial gradient and 2-stage time-dependent distribution, which was further simulated using a 3D finite element model. As demonstrated, in comparison with striped-patterned hydrogel, the triangular-patterned HGMH with highly anisotropic array of microcapsules exhibits remarkably spatial NT-3 gradient distributions that can not only guide neural stem cells (NSCs) migration but also facilitate spinal cord injury regeneration. This approach to construct hierarchical 4D hydrogel system via an electromicrofluidic platform demonstrates the potential for building various biomimetic soft scaffolds in vitro tailed to real soft tissues. [Display omitted] [ABSTRACT FROM AUTHOR]