Poly(N-vinyl imidazole) Cross-Linked ß-Cyclodextrin Hydrogel for Rapid Hemostasis in Severe Renal Arterial Hemorrhagic Model.

A unique facile process has been adopted for fast assembly of a poly(N-vinyl imidazole) cross-linked ß-cyclodextrin hydrogel through microwave-assisted free radical polymerization, using N,N'-methylenebis(acrylamide) cross-linker. The copolymer possesses positive surface charge, one of the characteristic properties of an ideal hemostatic hydrogel. The functionalized imidazole-based hydrogel demonstrates rapid, superior blood coagulation kinetics under in vitro and in vivo conditions. On application to a major renal arterial hemorrhagic model, this hydrogel shows better blood clotting kinetics, leading to complete hemostasis in as few as ∼144 ± 7 s. Additionally, 350 µL of whole blood was clotted instantly, in ∼35 s, and therefore, reinforcing its hemostatic potential. The hydrogel demonstrates excellent biocompatibility, when seeded with human dermal fibroblast cells, retaining the native property of its predecessor. In addition, the hydrogel presents excellent hemocompatibility when tested with whole blood with the highest hemolytic ratio of 1.07 ± 0.05%. Moreover, it also demonstrates potential as a carrier for sustained release of an anesthetic drug, lidocaine hydrochloride monohydrate (∼83% in 24 h). The rapid hemostatic behavior of the hydrogel is coupled with its cytocompatibility and hemocompatibilty properties along with controlled drug release characteristics. These behaviors evidently demonstrate it to be an excellent alternative for a superior hemostatic material for severe hemorrhagic conditions.

Glucose-Operated Widget (GLOW) for Closed-Loop Optogenetic Glycemic Control.

Closed-loop control systems for precise control of therapeutic gene expression are promising candidates for personalized treatment of chronic ailments such as diabetes. Pancreatic iß-cells are engineered with blue-light-inducible melanopsin to drive rapid insulin release by vesicular secretion from intracellular stores. In this work, a glucose-operated widget (GLOW) is designed as a component of a closed-loop control system for diabetes treatment by employing a probe that emits blue fluorescence in a glucose-concentration-dependent manner as a real-time glucose sensor to precisely control insulin release from these iß-cells. As proof-of-concept of the complete control system, the probe is encapsulated together with iß-cells in alginate-poly-(L-lysine) hydrogel-microbeads(400 µm in diameter and containing about 500 cells) called GLOWiß (GLOW with iß-cells), are subcutaneously implanted into type-1-diabetic (T1D) mice. Illumination by UV-A light at 390 nm results in glucose-concentration-dependent blue-light emission from the probe at 445 nm that in turn induces glucose-concentration-dependent insulin release from the iß-cells in a fully reversible manner. Activation of the injected GLOWiß at 390 nm for 15 min effectively restores normoglycemia within 60-120 min in a closed-loop manner in these diabetic mice. The system is robust, as normoglycemia is well maintained by daily activation for at least 7 days.

Blood-Glucose-Powered Metabolic Fuel Cell for Self-Sufficient Bioelectronics.

Currently available bioelectronic devices consume too much power to be continuously operated on rechargeable batteries, and are often powered wirelessly, with attendant issues regarding reliability, convenience, and mobility. Thus, the availability of a robust, self-sufficient, implantable electrical power generator that works under physiological conditions would be transformative for many applications, from driving bioelectronic implants and prostheses to programing cellular behavior and patients' metabolism. Here, capitalizing on a new copper-containing, conductively tuned 3D carbon nanotube composite, an implantable blood-glucose-powered metabolic fuel cell is designed that continuously monitors blood-glucose levels, converts excess glucose into electrical power during hyperglycemia, and produces sufficient energy (0.7 mW cm-2 , 0.9 V, 50 mm glucose) to drive opto- and electro-genetic regulation of vesicular insulin release from engineered beta cells. It is shown that this integration of blood-glucose monitoring with elimination of excessive blood glucose by combined electro-metabolic conversion and insulin-release-mediated cellular consumption enables the metabolic fuel cell to restore blood-glucose homeostasis in an automatic, self-sufficient, and closed-loop manner in an experimental model of type-1 diabetes.

A versatile bioelectronic interface programmed for hormone sensing.

Precision medicine requires smart, ultrasensitive, real-time profiling of bio-analytes using interconnected miniaturized devices to achieve individually optimized healthcare. Here, we report a versatile bioelectronic interface (VIBE) that senses signaling-cascade-guided receptor-ligand interactions via an electronic interface. We show that VIBE offers a low detection limit down to sub-nanomolar range characterised by an output current that decreases significantly, leading to precise profiling of these peptide hormones throughout the physiologically relevant concentration ranges. In a proof-of-concept application, we demonstrate that the VIBE platform differentiates insulin and GLP-1 levels in serum samples of wild-type mice from type-1 and type-2 diabetic mice. Evaluation of human serum samples shows that the bioelectronic device can differentiate between samples from different individuals and report differences in their metabolic states. As the target analyte can be changed simply by introducing engineered cells overexpressing the appropriate receptor, the VIBE interface has many potential applications for point-of-care diagnostics and personalized medicine via the internet of things.

pH-Responsive Copolymeric Network Gel Using Methacrylated ß-Cyclodextrin for Controlled Codelivery of Hydrophilic and Hydrophobic Drugs.

In medical science, sometimes two drugs with different solubilities are simultaneously required in combination to treat various diseases. Herein, a pH-responsive, copolymeric, antioxidant, biocompatible, and chemically crosslinked network gel is prepared to explore its capability as a matrix for controlled release of both hydrophobic [ibuprofen (IB)] and hydrophilic [tetracycline hydrochloride (TCH)] drugs, simultaneously. This three-dimensional ß-CD-Meth-cl-(PHPMA-co-PAAc) network hydrogel is synthesized via two steps: (I) methacrylation of ß-cyclodextrin and (II) grafting of poly(hydroxypropyl methacrylate) and poly(acrylic acid), followed by crosslinking of poly(ethylene glycol) diacrylate onto the backbone of methacrylated ß-cyclodextrin (ß-CD-Meth). The successful synthesis of the hydrogel is confirmed using several physiochemical characterizations. The ß-CD-Meth-cl-(PHPMA-co-PAAc) hydrogel has an excellent network-like surface morphology. The potential pH-responsive high swelling behavior and excellent shrinking features suggest the reversible nature of the synthesized gel. Besides, rheological analyses affirm its excellent viscoelastic nature. This network gel is biodegradable and its non-cytotoxic nature toward human dermal fibroblast cells is demonstrated. Moreover, the dual drug release pattern from the copolymer under both in vitro and in vivo conditions portrays that this hydrogel has superior ability to be used as a controlled release matrix for both hydrophobic and hydrophilic drugs (TCH and IB) with varying solubilities concurrently.

Metal Ion Augmented Mussel Inspired Polydopamine Immobilized 3D Printed Osteoconductive Scaffolds for Accelerated Bone Tissue Regeneration.

Critical bone defects with a sluggish rate of auto-osteoconduction and imperfect reconstruction are motivators for the development of an alternate innovative approach for the regeneration of bone. Tissue engineering for bone regeneration signifies an advanced way to overcome this problem by creating an additional bone tissue substitute. Among different fabrication techniques, the 3D printing technique is obviously the most efficient and advanced way to fabricate an osteoconductive scaffold with a controlled porous structure. In the current article, the polycarbonate and polyester diol based polyurethane-urea (P12) was synthesized and 3D porous nanohybrid scaffolds (P12/TP-nHA) were fabricated using the 3D printing technique by incorporating the osteoconductive nanomaterial titanium phosphate adorned nanohydroxyapatite (TP-nHA). To improve the bioactivity, the surface of the fabricated scaffolds was modified with the immobilized biomolecule polydopamine (PDA) at room temperature. XPS study as well as the measurement of surface wettability confirmed the higher amount of PDA immobilization on TP-nHA incorporated nanohybrid scaffolds through the dative bone formation between the vacant d orbital of the incorporated titanium ion and the lone pair electron of the catechol group of dopamine. The incorporated titanium phosphate (TP) increased the tensile strength (53.1%) and elongation at break (96.8%) of the nanohybrid composite as compared to pristine P12. Moreover, the TP incorporated nanohybrid scaffold with calcium and phosphate moieties and a higher amount of immobilized active biomolecule improved the in vitro bioactivity, including the cell viability, cell proliferation, and osteogenic gene expression using hMSCs, of the fabricated nanohybrid scaffolds. A rat tibia defect model depicted that the TP incorporated nanohybrid scaffold with immobilized PDA enhanced the in vivo bone regeneration ability compared to the control sample without revealing any organ toxicity signifying the superior osteogenic bioactivity. Thus, a TP augmented polydopamine immobilized polyurethane-urea based nanohybrid 3D printed scaffold with improved physicochemical properties and osteogenic bioactivity could be utilized as an excellent advanced material for bone regeneration substitute.

Nanoinspired Biocompatible Chemosensors: Progress toward Efficient Prognosis of Arsenic Poisoning.

Diagnosing heavy metals poisoning in human beings is of paramount importance. In this work, we present the design of a biocompatible FexNi(1-x)O hierarchical nanostructure-based sensor for ultraselective detection of arsenate (As(V)) ions in biological environments (e.g., body fluids, blood plasma, etc.). A novel iron doping technique was employed to fabricate the nanostructures rich with Fe cores to induce ultraselectivity toward arsenates. These nanostructures were used as dispersed markers and thin films deposited on Si/SiO2 substrates to support in vivo and in vitro detection of As(V) ions. The device demonstrated excellent sensitivity with a maximum response of 64.7% (for 1000 ppm As(V) ions) with a limit of detection of 1 ppb in blood plasma. The sensor's response time (τr) was 5 s with 95.48% recovery with a maximum error of ±0.549% after three washes. The device showed excellent response stability for 63 days with a maximum error of ±1.27%. The sensor devices were highly reproducible, with a maximum variation of ±0.6% in response for a batch of four devices. Due to Fe doping, the nanostructures in suspension demonstrated as arsenate markers with excellent cytocompatibility (with dosage up to 1 mg/mL) for human umbilical vein endothelial cells and 3T3 fibroblasts (LDH < 120 and cell viability ∼80%) till 48 h of incubation. The sensing mechanism suggested that the nanostructures not only detect arsenates but also prevent their substantial reduction to arsenites under anoxic environments. Thus, the sensors may show considerable progress toward early arsenate detection in living systems.

Raman spectroscopy assisted biochemical evaluation of L929 fibroblast cells on differentially crosslinked gelatin hydrogels.

Biochemical evaluation of cell-matrix interaction using conventional labelling techniques often possesses limitations due to dye entrapment. In contrast, Raman spectroscopy guided approach offers label-free determination of cell-matrix biochemistry. Herein, gelatin (Gel) matrices modified with 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/ N-Hydroxysuccinimide (EDC/NHS) and glutaraldehyde (GTA) was used as standards for comparative evaluation. Raman spectroscopy was deployed as a label-free approach to investigate interaction of cells with Gel hydrogels. Raman-based approach assisted in evaluation of cell-matrix interactions by identifying key biomolecular signatures retrospecting the fact that L929 fibroblast cells portrayed excellent growth and proliferation kinetics in crosslinked Gel as compared to its bare counterpart. EDC crosslinked hydrogels exhibited superior cell proliferation than its GTA counterparts. Cell proliferation on differentially crosslinked gel was also confirmed using standard MTT Assay and Rhodamine-DAPI staining thus corroborating the fact that Raman spectroscopy can be deployed as a superior label-free alternative towards real-time determination of cell proliferation and growth.

Direct 3D Printing of Seashell Precursor toward Engineering a Multiphasic Calcium Phosphate Bone Graft.

Multiphasic calcium phosphate (Ca-P) has widely been explored for bone graft replacement. This study represents a simple method of developing osteoinductive scaffolds by direct printing of seashell resources. The process demonstrates a coagulation-assisted extrusion-based three-dimensional (3D) printing process for rapid fabrication of multiphasic calcium phosphate-incorporated 3D scaffolds. These scaffolds demonstrated an interconnected open porous architecture with improved compressive strength and higher surface area. Multiphasic calcium phosphate (Ca-P) and hydroxyapatite present in the multi-scalar naturally resourced scaffold displayed differential protein adsorption, thus facilitating cell adhesion, migration, and differentiation, resulting in enhanced deposition of the extracellular matrix. The microstructural and physicochemical attributes of the scaffolds also lead to enhanced stem cell differentiation as witnessed from gene and protein expression analysis. Furthermore, the histological study of subcutaneous implantation evidently portrays promising biocompatibility without foreign body reaction. Neo-tissue in-growth was manifested with abundant blood vessels, thus indicative of excellent vascularization. Notably, cartilaginous and proteoglycan-rich tissue deposition indicated ectopic bone formation via an endochondral ossification pathway. The hierarchical interconnected porous architectural tribology accompanied with multiphasic calcium phosphate composition manifests its successful implication in enhancing stem cell differentiation and promoting excellent tissue in-growth, thus making it a plausible alternative in bone tissue engineering applications.

Tailorable hydrogel of gelatin with silk fibroin and its activation/crosslinking for enhanced proliferation of fibroblast cells.

Gelatin based hydrogel (Gel) possess remarkable cytocompatibility profile rendering it appropriate for tissue engineering applications. Herein, the questionable mechanical property of Gel was tuned by tailoring with different loading concentrations of silk fibroin (SF). The as tailored matrix was reconnoitred for its physico-mechanical, chemical and biological properties in order to investigate the effect of SF loading. Ethanol treatment lead to enhance ß-sheet formation of silk and subsequently, carbodiimide coupling was deployed to covalently crosslink the matrix. Substantial increase in cohesive energy with amplifying concentration of SF in the Gel matrix. As evidenced by Raman spectroscopy, right shift of the Amide I peak and stretching of COO- confirms activation of fibroin moiety along with crosslinking of gelatin, respectively. Moreover, with addition of SF, surface properties were tuned to attain maximum cell adhesion and proliferation. Further, MTT assay corroborated the same with definite increase in mitochondrial activities of L929 fibroblast cells for SF containing matrix as compared to its bare counterfeit while enhanced proliferation was confirmed by Rhodamine-DAPI staining. The alteration in mechanical and textural tribology of SF tailored Gel matrix certainly portrayed improved stability along with excellent cytocompatibility thus making it a plausible alternative in regenerative medicine.

Surface Modification of Eggshell Membrane with Electrospun Chitosan/Polycaprolactone Nanofibers for Enhanced Dermal Wound Healing.

Eggshell membrane (ESM), a naturally occurring microfibrous biopolymer network comprising collagen I, V, and X, GAGs, and other significant proteins, is responsible for guided tissue regeneration. The extraction methodology of ESM and surface topography of the microfibers impede its extensive usage in skin tissue engineering. Herein we deploy a unique route of ESM surface modification utilizing chitosan/polycaprolactone (CS/PCL) nanofibers to fabricate a bilayered scaffold for wound healing application. Microstructural and surface topographic analysis of the construct confirms the bilayered structure of the composite with smooth nanofibers of CS/PCL decorated on ESM. The two layers were cross-linked by carbodiimide chemistry as confirmed by XPS and FTIR analysis. Cytocompatibility of the scaffolds was evaluated with human dermal fibroblast (HDF) cells culture study. The biomimetic architecture and composition of modified ESM facilitated extensive cell adhesion, migration, and proliferation while an impeded cell adhesion was observed on the natural tissue. Moreover, owing to the presence of ESM, the scaffolds adhered naturally to the wound bed while implanted on a full-thickness wound in a rat model. Further, the nanofiber modified ESM group showed extensive host cell migration and proliferation thus leading to faster re-epithelization and dermal regeneration with high collagen deposition in comparison to natural ESM. The above in vitro and in vivo results substantiate the effect of nanofiber functionalization on the ESM surface thus making the bilayered construct a potential dermal substitute.