Tortuosity Engineering of Water Channels to Customized Water Supply for Enhancing Hydrogel Solar Evaporation.

Hydrogel as a solar evaporator shows great potential in freshwater production. However, hydrogels often lead to an imbalance between solar energy input and water supply management due to their excessively high saturated water content. Thus, achieving a stable water-energy-balance in hydrogel evaporators remains challenging. Here, by tortuosity engineering designed water transport channels, a seamless high-tortuosity/low-tortuosity/high-tortuosity structured hydrogel (SHLH structure hydrogel) evaporator is developed, which enables the hydrogel with customized water transport rate, leading to the controlled water supply at the evaporator interface. An excellent equilibrium between the photothermal conversion and water supply is established, and the maximum utilization of solar energy is realized, thereby achieving an excellent evaporation rate of 3.64 kg m-2 h-1 under one solar illumination. This tortuosity engineering controlled SHLH structured evaporator provides a novel strategy to attain water-energy-balance and expands new approaches for constructing hydrogel-based evaporators with tailored water transportation capacity.

Functionalization of Alginate Hydrogels with a Multifunctional Peptide Supports Mesenchymal Stem Cell Adhesion and Reduces Bacterial Colonization.

Hydrogels with cell adhesive moieties stand out as promising materials to enhance tissue healing and regeneration. Nonetheless, bacterial infections of the implants represent an unmet major concern. In the present work, we developed an alginate hydrogel modified with a multifunctional peptide containing the RGD cell adhesive motif in combination with an antibacterial peptide derived from the 1-11 region of lactoferrin (LF). The RGD-LF branched peptide was successfully anchored to the alginate backbone by carbodiimide chemistry, as demonstrated by 1H NMR and fluorescence measurements. The functionalized hydrogel presented desirable physicochemical properties (porosity, swelling and rheological behavior) to develop biomaterials for tissue engineering. The viability of mesenchymal stem cells (MSCs) on the peptide-functionalized hydrogels was excellent, with values higher than 85 % at day 1, and higher than 95 % after 14 days in culture. Moreover, the biological characterization demonstrated the ability of the hydrogels to significantly enhance ALP activity of MSCs as well as to decrease bacterial colonization of both Gram-positive and Gram-negative models. Such results prove the potential of the functionalized hydrogels as novel biomaterials for tissue engineering, simultaneously displaying cell adhesive activity and the capacity to prevent bacterial contamination, a dual bioactivity commonly not found for these types of hydrogels.

Carbon dots-facilitated on-demand dissolution of Ca-alginate hydrogel via site-specific mineralization for wound healing.

On-demand dissolution of hydrogels has shown much potential in easy and pain-free removal of wound dressings. This work firstly describes a type of carbon dots (CDs) for dissolving Ca-alginate hydrogel via site-specific mineralization method. The CDs were characterized by two features, which included presence of primary/secondary amine groups and generation of calcium crystals with Ca2+. Especially, the amount of primary/secondary amine groups on CDs played key role in determining whether hydrogel could be dissolved. When there were sufficient primary/secondary amine groups, the mineralization occurred on CDs rather than alginates due to the hydrogen bond between primary/secondary amine and carboxyl of alginates. Thereby, this promoted the gel-sol transition through Ca2+ capture from the hydrogels. Moreover, antibacterial test revealed Ca2+ capture from cell walls, while in vivo test revealed hypoxia relief due to porous structures of the renewed hydrogels. Overall, CDs with sufficient primary/secondary amine groups could dissolve Ca-alginate hydrogel through site-specific mineralization method, accompanying by additional functions of antibacterial and hypoxia relief.

Green NiO nanoparticle-integrated PVA-alginate hydrogel: potent nanocatalyst for efficient reduction of anthropogenic water pollutants.

Hydrogel nanocatalyst composed of nickel oxide (NiO) nanoparticles embedded in PVA-alginate hydrogels were potentially explored toward the reduction of anthropogenic water pollutants. The NiO nanoparticles was accomplished via green method using waste pineapple peel extract. The formation of the nanoparticles was affirmed from different analytical techniques such as UV-Vis, FTIR, XRD, TGA, FESEM, and EDS. Spherical NiO nanoparticles were obtained having an average size of 11.5 nm. The nano NiO were then integrated into PVA-alginate hydrogel matrix forming a nanocomposite hydrogel (PVALg@ NiO). The integration of nano NiO rendered an improved thermal stability to the parent hydrogel. The PVALg@ NiO hydrogel was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP), potassium hexacyanoferrate (III), rhodamine B (RhB), methyl orange (MO), and malachite green (MG) in the presence of a reducing agent, i.e., NaBH4. Under optimized conditions, the reduction reactions were completed by 4.0 min and 3.0 min for 4-NP and potassium hexacyanoferrate (III), respectively, and the rate constant was estimated to be 1.14 min-1 and 2.15 min-1. The rate of reduction was found to be faster for the dyes and the respective rate constants were be 0.17 s-1 for RhB, MG and 0.05 s-1 for MO. The PVALg@ NiO hydrogel nanocatalyst demonstrated a recyclability of four runs without any perceptible diminution in its catalytic mettle. The efficacy of the PVALg@ NiO hydrogel nanocatalyst was further examined for the reduction of dyes in real water samples collected from different sources and the results affirm its high catalytic potential. Thus, this study paves the path for the development of a sustainable hydrogel nanocatalyst for reduction of hazardous pollutants in wastewater treatment.

A Nanoparticle Ink Allowing the High Precision Visualization of Tissue Engineered Scaffolds by MRI.

Hydrogels are widely used as cell scaffolds in several biomedical applications. Once implanted in vivo, cell scaffolds must often be visualized, and monitored overtime. However, cell scaffolds appear poorly contrasted in most biomedical imaging modalities such as magnetic resonance imaging (MRI). MRI is the imaging technique of choice for high-resolution visualization of low-density, water-rich tissues. Attempts to enhance hydrogel contrast in MRI are performed with "negative" contrast agents that produce several image artifacts impeding the delineation of the implant's contours. In this study, a magnetic ink based on ultra-small iron oxide nanoparticles (USPIONs; <5 nm diameter cores) is developed and integrated into biocompatible alginate hydrogel used in cell scaffolding applications. Relaxometric properties of the magnetic hydrogel are measured, as well as biocompatibility and MR-visibility (T1 -weighted mode; in vitro and in vivo). A 2-week MR follow-up study is performed in the mouse model, demonstrating no image artifacts, and the retention of "positive" contrast overtime, which allows very precise delineation of tissue grafts with MRI. Finally, a 3D-contouring procedure developed to facilitate graft delineation and geometrical conformity assessment is applied on an inverted template alginate pore network. This proof-of-concept establishes the possibility to reveal precisely engineered hydrogel structures using this USPIONs ink high-visibility approach.

Stable hydrogel adhesion to polydimethylsiloxane enables cyclic mechanical stimulation of 3D-bioprinted smooth muscle constructs.

During normal urination, smooth muscle cells (SMCs) in the lower urinary tract (LUT) are exposed to mechanical signals that have a critical impact on tissue structure and function. Nevertheless, the mechanisms underlying the maintenance of the contractile phenotype of SMCs remain poorly understood. This is due, in part, to a lack of studies that have examined the effects of mechanical loading using three-dimensional (3D) models. In this study, surface modifications of polydimethylsiloxane (PDMS) membrane were evaluated to investigate the effects of cyclic mechanical stimulation on SMC maturation in 3D constructs. Commercially available cell stretching plates were modified with amino or methacrylate groups to promote adhesion of 3D constructs fabricated by bioprinting. After 6 days of stimulation, the effects of mechanical stimulation on the expression of contractile markers at the mRNA and protein levels were analyzed. Methacrylate-modified surfaces supported stable adhesion of the 3D constructs to the membrane and facilitated cyclic mechanical stimulation, which significantly increased the expression of contractile markers at the mRNA and protein levels. These effects were found to be mediated by activation of the p38 MAPK pathway, as inhibition of this pathway abolished the effects of stimulation in a dose-dependent manner. These results provide valuable insights into the role of mechanical signaling in maintaining the contractile phenotype of bladder SMCs, which has important implications for the development of future treatments for LUT diseases.

Strong infiltrative HHC36 antimicrobial peptide/silver nanoparticles-loaded carboxymethyl chitosan/sodium alginate hydrogel for acne vulgaris therapy.

Acne is a common chronic skin inflammatory disease closely related toCutibacterium acnes(C. acnes), which affects the life quality of patients worldwide, especially adolescents and young adults. However, the physical barrier of the skin makes drugs difficult to infiltrate effectively into infected site, causing acne hard to cure and easy to recur. Herein, we developed an antibacterial skin dressing with strong infiltration of antibacterial agents which can co-delivery small-molecular antimicrobial agents through stratum corneum deeply into dermis, achieving high antimicrobial efficacy. The antibacterial dressings were constructed with carboxymethyl chitosan/sodium alginate (CMCS/SA) hydrogel loading with HHC36 (an antimicrobial peptide) and silver nanoparticles (AgNPs) conjugates (Ag-H2/CMCS/SA hydrogel). The released Ag-H2from Ag-H2/CMCS/SA hydrogel can early infiltrate into dermis, co-delivery HHC36 and AgNPs due to the infiltration and targeting of HHC36, presenting the superior antibacterial effect compared to HHC36 or AgNPs alone and killing 100%C. acnesand 100%Staphylococcus epidermidis(S. epidermidis) at a very low concentration of Ag-H2(15µg ml-1A g with 7.1µg ml-1HHC36). Meanwhile, Ag-H2/CMCS/SA hydrogel was biocompatible due to the natural polysaccharides carboxymethyl chitosan and sodium alginate. The HaCaT cells spread well in Ag-H2/CMCS/SA hydrogel. These results indicate that the co-delivery small-molecular antimicrobial agents is a promising strategy and Ag-H2/CMCS/SA hydrogel has a great potential in the therapy of acne.

Characterization and optimization of bioluminescent bacterial cells immobilization process in calcium alginate hydrogel tablets.

AIMS: Whole-cell biosensors are increasingly utilized in various applications. These platforms integrate cells with a signal measurement device. One of the main challenges in the development of such platforms is the immobilization matrix that is used to keep the cells stable, which also affects the portability of the device. In this study, a portable and simple immobilization of bioluminescent bacterial cells in calcium alginate hydrogel was examined. METHODS AND RESULTS: The effects of several physical parameters were investigated (e.g. calcium alginate solution volume, drying, incubation time, mixing procedure, bacterial concentration, and tablet location within the cylinder). An alginate solution volume of 3 ml was preferred as well as the addition of 400 µl solution after the 15 min of compressing step and before the polymerization step. Also, a stirring mixing mode is favored over vortexing due to the creation of better homogenized tablets, as well as a bacterial concentration of 0.15 OD600nm that produced a high light response while maintaining a lower variance. Lastly, the findings showed a significantly higher response [induction factor (IF)] in the tablets using the optimized immobilization protocol (IF = 8.814) than the old one (IF = 1.979). CONCLUSIONS: To conclude, bacterial cells immobilization in calcium alginate tablets provides improved sensitivity and storability.

Gold-nanoparticle-embedded hydrogel droplets with enhanced fluorescence for imaging and quantification of proteins in cells.

Conventional cellular protein detection techniques such as immunocytochemistry and flow cytometry require abundant cells, posing multiple challenges, including difficulty and cost for obtaining enough cells and the potential for clogging the instrument when using flow cytometry. Also, it is challenging to conduct cellular protein imaging and quantification simultaneously from a single experiment. We present a novel 3D platform, which integrates highly biocompatible cell-entrapped alginate hydrogel droplet array with gold-nanoparticle (AuNP)-based metal enhanced fluorescence (MEF), to achieve simultaneous imaging and quantification of proteins in intact cells in a sensitive manner. Compared to 2D immunocytochemistry, this 3D system allows for a higher cell loading capacity per unit area; together with the MEF-based signal enhancement from the embedded AuNPs, sensitive protein quantification was realized. Furthermore, compared to flow cytometry, this platform allows for protein imaging from individual cells. Taking the detection of EpCAM protein in ovarian cancer cells as a model, we optimized the AuNP size and concentration for optimal fluorescent signals. The 5 nm AuNPs at 6.54 × 1013 particles/mL proved to be the most effective in signal enhancement, providing 2.4-fold higher signals compared to that without AuNPs and 6.4-fold higher signals than that of 2D immunocytochemistry. The number of cells required in our technology is 1-3 orders of magnitude smaller than that of conventional methods. This AuNP-embedded hydrogel platform combines the benefits of immunocytochemistry and flow cytometry, providing increased assay sensitivity while also allowing for qualitative analysis through imaging, suitable for protein determination in a variety of cells.

Ions-Induced Alginate Gelation According to Elemental Analysis and a Combinatorial Approach.

This study considers the potential of elemental analysis of polysaccharide ionotropic gels in elucidating the junction zones for different divalent cations. The developed algorithm ensures the correct separation of contributions from physically adsorbed and structure-forming ionic compounds, with the obtained results scaled to alginate C12 block. Possible versions of chain association into dimers and their subsequent integration into flat junction zones were analyzed within the framework of the "egg-box" model. The application of combinatorial analysis made it possible to derive theoretical relations to find the probability of various types of egg-box cell occurrences for alginate chains with arbitrary monomeric units ratio µ = M/G, which makes it possible to compare experimental data for alginates of different origins. Based on literature data and obtained chemical formulas, the possible correspondence of concrete biopolymer cells to those most preferable for filling by alkaline earth cations was established. The identified features of elemental composition suggest the formation of composite hydrated complexes with the participation of transition metal cations. The possibility of quantitatively assessing ordered secondary structures formed due to the physical sorption of ions and molecules from environment, correlating with the sorption capabilities of Me2+ alginate, was established.

Flexible Curcumin-Loaded Zn-MOF Hydrogel for Long-Term Drug Release and Antibacterial Activities.

Management of chronic inflammation and wounds has always been a key issue in the pharmaceutical and healthcare sectors. Curcumin (CCM) is an active ingredient extracted from turmeric rhizomes with antioxidant, anti-inflammatory, and antibacterial activities, thus showing significant effectiveness toward wound healing. However, its shortcomings, such as poor water solubility, poor chemical stability, and fast metabolic rate, limit its bioavailability and long-term use. In this context, hydrogels appear to be a versatile matrix for carrying and stabilizing drugs due to their biomimetic structure, soft porous microarchitecture, and favorable biomechanical properties. The drug loading/releasing efficiencies can also be controlled via using highly crystalline and porous metal-organic frameworks (MOFs). Herein, a flexible hydrogel composed of a sodium alginate (SA) matrix and CCM-loaded MOFs was constructed for long-term drug release and antibacterial activity. The morphology and physicochemical properties of composite hydrogels were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, and mechanical property tests. The results showed that the composite hydrogel was highly twistable and bendable to comply with human skin mechanically. The as-prepared hydrogel could capture efficient CCM for slow drug release and effectively kill bacteria. Therefore, such composite hydrogel is expected to provide a new management system for chronic wound dressings.

Hydrogel loaded with exosomes from Wharton's Jelly-derived mesenchymal stem cells enhances wound healing in mice. / 负载Wharton's Jelly源间å è´¨å¹²ç»†èƒžæ¥æºå¤–æ³Œä½“çš„æ°´å‡èƒ¶å¯ä¿ƒè¿›å°é¼ åˆ›é¢ä¿®å¤.

OBJECTIVES: To explore the effect of hydrogel loaded with exosomes from Wharton's Jelly-derived mesenchymal stem cell (WJMSC) on wound healing. METHODS: Exosomes were extracted from WJMSC, and the morphology and size of WJMSC-derived exosomes (WEX) were analyzed by transmission electron microscopy and nanoparticle size analyzer, respectively. The surface markers CD9, CD81, and Calnexin of WEX were detected by Western blotting. Exosome-loaded alginate hydrogel (WEX-gel) was prepared; its morphology was studied by scanning electron microscope, and its rheological behavior was examined by a rheometer. The in vitro drug release performance of WEX-gel was investigated by BCA method. RAW264.7 cells were treated with alginate hydrogel, WEX and WEX-gel, respectively; and the expression of CD86 and CD206 in macrophages was detected by flow cytometry. A full-thickness skin wound model was established in mice; the model mice were randomly divided into blank control group, WEX control group and WEX-gel group, and PBS, WEX and WEX-gel were applied to the wound area of mice, respectively. On day 3, the skin tissue of mice was excised, and the antibacterial effect of WEX hydrogel was evaluated by plate counting. On day 15, the mice were euthanized and the percentage of residual wounds was calculated. The histological changes of the skin wound were observed after hematoxylin and eosin (HE) and Masson stainings. The expression of CD86, CD206, CD31 and vascular endothelial growth factor (VEGF) in the skin wound tissue was detected by immunohistochemistry. RESULTS: Exosomes were successfully extracted from WJMSC. WEX-gel presented a regular three-dimensional network structure, good rheology and controlled drug release performance. WEX-gel promoted the polarization of RAW264.7 cells from the M1 phenotype to M2 phenotype in vitro. The residual wound percentage in blank control group, WEX control group and WEX-gel group were (27.5±3.4)%, (15.3±1.2)% and (7.6±1.1)%, respectively (P<0.05). The antibacterial property of WEX-gel is better than that of WEX (P<0.05). The dermis thickness, the number of new hair follicles, and the rate of collagen deposition in the WEX-gel group were significantly higher than those in the other two groups (all P<0.05). The expression of CD206, CD31 and VEGF in skin wound tissue was higher and the expression of CD86 was lower in WEX-gel group than those in other two groups (all P<0.05). CONCLUSIONS: WEX-gel can significantly promote wound healing in mice by regulating the polarization of macrophages.

Afterglow Implant for Arterial Embolization and Intraoperative Imaging.

Transcatheter arterial embolization (TAE) is wildly used in clinical treatments. However, the online monitoring of the thrombosis formation is limited due to the challenges of the direct visualization of embolic agents and the real-time monitoring of dynamic blood flow. Thus, we developed a photochemical afterglow implant with strong afterglow intensity and a long lifetime for embolization and imaging. The liquid pre-implant injected into the abdominal aorta of mice was rapidly transformed into a hydrogel in situ to embolize the blood vessel. The vascular embolism position can be observed by the enhanced afterglow of the fixed implant, and the long lifetime of afterglow can also be used to monitor the effect of embolization. This provides an excellent candidate in bio-imaging to avoid the autofluorescence interference from continuous light excitation. The study suggests the potential usefulness of the implant as an embolic agent in TAE and artery imaging during a surgical procedure.

Use of alginate hydrogel to improve long-term 3D culture of spermatogonial stem cells: stemness gene expression and structural features.

The quality and quantity of a spermatogonial stem-cell (SSC) culture can be measured in less time using a 3D culture in a scaffold. The present study investigated stemness gene expression and the morphological and structural characterization of SSCs encapsulated in alginate. SSCs were harvested from BALB/c neonatal mice testes through two-step mechanical and enzymatic digestion. The spermatogonial populations were separated using magnetic-activated cell sorting (MACS) using an anti-Thy1 antibody and c-Kit. The SSCs then were encapsulated in alginate hydrogel. After 2 months of SSC culturing, the alginate microbeads were extracted and stained to evaluate their histological properties. Real-time polymerase chain reaction (PCR) was performed to determine the stemness gene expression. Scanning electron microscopy (SEM) was performed to evaluate the SSC morphology, density and scaffold structure. The results showed that encapsulated SSCs had decreased expression of Oct4, Sox2 and Nanos2 genes, but the expression of Nanog, Bcl6b and Plzf genes was not significantly altered. Histological examination showed that SSCs with pale nuclei and numerous nucleolus formed colonies. SEM evaluation revealed that the alginate scaffold structure preserved the SSC morphology and density for more than 60 days. Cultivation of SSCs on alginate hydrogel can affect Oct4, Sox2 and Nanos2 expression.

Evaluation of co-cultured spermatogonial stem cells encapsulated in alginate hydrogel with Sertoli cells and their transplantation into azoospermic mice.

An in vitro spermatogonial stem cell (SSC) culture can serve as an effective technique to study spermatogenesis and treatment for male infertility. In this research, we compared the effect of a three-dimensional alginate hydrogel with Sertoli cells in a 3D culture and co-cultured Sertoli cells. After harvest of SSCs from neonatal mice testes, the SSCs were divided into two groups: SSCs on a 3D alginate hydrogel with Sertoli cells and a co-culture of SSCs with Sertoli cells for 1 month. The samples were evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays and bromodeoxyuridine (BrdU) tracing, haematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining after transplantation into an azoospermic testis mouse. The 3D group showed rapid cell proliferation and numerous colonies compared with the co-culture group. Molecular assessment showed significantly increased integrin alpha-6, integrin beta-1, Nanog, Plzf, Thy-1, Oct4 and Bcl2 expression levels in the 3D group and decreased expression levels of P53, Fas, and Bax. BrdU tracing, and H&E and PAS staining results indicated that the hydrogel alginate improved spermatogenesis after transplantation in vivo. This finding suggested that cultivation of SSCs on alginate hydrogel with Sertoli cells in a 3D culture can lead to efficient proliferation and maintenance of SSC stemness and enhance the efficiency of SSC transplantation.

The Design of Rapid Self-Healing Alginate Hydrogel with Dendritic Crosslinking Network.

Self-healing alginate hydrogels play important roles in the biological field due to their biocompatibility and ability to recover after cracking. One of the primary targets for researchers in this field is to increase the self-healing speed. Sodium alginate was oxidized, generating aldehyde groups on the chains, which were then crosslinked by poly(amino) amine (PAMAM) via Schiff base reaction. The dendritic structure was introduced to the alginate hydrogel in this work, which was supposed to promote intermolecular interactions and accelerate the self-healing process. Results showed that the hydrogel (ADA-PAMAM) formed a gel within 2.5 min with stable rheological properties. Within 25 min, the hydrogel recovered under room temperature. Furthermore, the aldehyde degree of alginate dialdehyde with a different oxidation degree was characterized through gel permeation chromatograph aligned with multi-angle laser light scattering and ultraviolet (UV) absorption. The chemical structure of the hydrogel was characterized through Fourier transform infrared spectroscopy and UV-vis spectra. The SEM and laser scanning confocal microscope (CLSM) presented the antibiotic ability of ADA-PAMAM against both S. aureus and E. coli when incubated with 10-7 CFU microorganism under room temperature for 2 h. This work presented a strategy to promote the self-healing of hydrogel through forming a dendritic dynamic crosslinking network.

Engineered cell-laden alginate microparticles for 3D culture.

Advanced microfabrication technologies and biocompatible hydrogel materials facilitate the modeling of 3D tissue microenvironment. Encapsulation of cells in hydrogel microparticles offers an excellent high-throughput platform for investigating multicellular interaction with their surrounding microenvironment. Compartmentalized microparticles support formation of various unique cellular structures. Alginate has emerged as one of the most dominant hydrogel materials for cell encapsulation owing to its cytocompatibility, ease of gelation, and biocompatibility. Alginate hydrogel provides a permeable physical boundary to the encapsulated cells and develops an easily manageable 3D cellular structure. The interior structure of alginate hydrogel can further regulate the spatiotemporal distribution of the embedded cells. This review provides a specific overview of the representative engineering approaches to generate various structures of cell-laden alginate microparticles in a uniform and reproducible manner. Capillary nozzle systems, microfluidic droplet systems, and non-chip based high-throughput microfluidic systems are highlighted for developing well-regulated cellular structure in alginate microparticles to realize potential drug screening platform and cell-based therapy. We conclude with the discussion of current limitations and future directions for realizing the translation of this technology to the clinic.

3D printed alginate bead generator for high-throughput cell culture.

Alginate hydrogel beads are a common platform for generating 3D cell cultures in biomedical research. Simple methods for bead generation using a manual pipettor or syringe are low-throughput and produce beads showing high variability in size and shape. To address these challenges, we designed a 3D printed bead generator that uses an airflow to cleave beads from a stream of hydrogel solution. The performance of the proposed alginate bead generator was evaluated by changing the volume flow rates of alginate (QAlg) and air (QA), the diameter of device nozzle (d) and the concentration of alginate gel solution (C). We identified that the diameter of beads (D = 0.9 -2.8 mm) can be precisely controlled by changing QA and d. Also the bead generation frequency (f) can be tuned by changing QAlg. Finally, we demonstrated that viability and biological function (pericellular matrix deposition) of chondrocytes were not adversely affected by high f using this bead generator. Because 3D printing is becoming a more accessible technique, our unique design will allow greater access to average biomedical research laboratories, STEM education and industries in cost- and time-effective manner.

Parametric Optimization of 3D Printed Hydrogel-Based Cardiovascular Stent.

PURPOSE: This study aimed to develop personalized biodegradable stent (BDS) for the treatment of coronary heart disease. Three-dimensional (3D) printing technique has offered easy and fast fabrication of BDS with enhanced reproducibility and efficacy. METHODS: A variety of BDS were printed with 3 types of hydrogel (~5 ml) resources (10%w/v sodium alginate (SA), 10%w/v cysteine-sodium alginate (SA-CYS), and 10%w/v cysteine-sodium alginate with 0.4%w/v PLA-nanofibers (SA-CYS-NF)) dispersed from an 22G print head nozzle attached to the BD-syringe. The printability of hydrogels into 3D structures was examined based on such variables as hydrogel's viscosity, printing distance, printing speed and the nozzle size. RESULTS: It was demonstrated that alginate composition (10%w/v) offered BDS with sufficient viscosity that defined the thickness and swelling ratio of the stent struts. The thickness of the strut was found to be 338.7 ± 29.3 µm, 262.5 ± 14.7 µm and 237.1 ± 14.7 µm for stents made of SA, SA-CYS and SA-CYS-NF, respectively. SA-CYS-NF stent displayed the highest swelling ratio of 38.8 ± 2.9% at the initial 30 min, whereas stents made of SA and SA-CYS had 23.1 ± 2.4% and 22.0 ± 2.4%, respectively. CONCLUSION: The printed stents had sufficient mechanical strength and were stable against pseudo-physiological wall shear stress. An addition of nanofibers to alginate hydrogel significantly enhanced the biodegradation rates of the stents. In vitro cell culture studies revealed that stents had no cytotoxic effects on human umbilical vein endothelial cells (HUVECs) and Raw 264.7 cells (i.e., Monocyte/macrophage-like cells), supporting that stents are biocompatible and can be explored for future clinical applications.

Alginate hydrogels: Sustained release system to analyze the effect of traditional excipients on curcumin availability.

Curcumin, a molecule of immense pharmacological significance is also known to exhibit poor aqueous solubility and low bioavailability. Different strategies have been adopted to enhance the aqueous solubility of curcumin, but report on the effect of traditional excipients on curcumin solubility still stand in need of. Here, we presented the significance of different traditional excipients used in anti-inflammatory formulations on curcumin solubility. The endeavor has been undertaken with the hypothesis that "traditional formulation used since ages have a scientific basis". To meet the quest we encapsulated 28 different formulations containing varying concentrations of milk, sugar, cow milk fat, and black pepper in alginate hydrogels. After the characterization of formulations through FT-IR, solubility studies were conducted. Milk was found to be an essential component for improved curcumin availability. Individually, cow milk fat and piperine exhibited lesser effect but their synergistic effect was observed in the presence of milk. Dual behavior of sugar has been observed. Traditionally used excipients greatly enhanced the solubility of curcumin. The results have also been validated through anti-oxidant activities of different formulations. Intermolecular interactions have been explained using Molecular modeling studies.