In regenerative medicine, natural protein-based polymers offer enhanced endogenous bioactivity and potential for seamless integration with tissue, yet form weak hydrogels that lack the physical robustness required for surgical manipulation, making them difficult to apply in practice. The use of higher concentrations of protein, exogenous cross-linkers, and blending synthetic polymers has all been applied to form more mechanically robust networks. Each relies on generating a smaller network mesh size, which increases the elastic modulus and robustness, but critically inhibits cell spreading and migration, hampering tissue regeneration. Here we report two unique observations; first, that colloidal suspensions, at sufficiently high volume fraction (ϕ), dynamically assemble into a fully percolated 3D network within high-concentration protein polymers. Second, cells appear capable of leveraging these unique domains for highly efficient cell migration throughout the composite construct. In contrast to porogens, the particles in our system remain embedded within the bulk polymer, creating a network of particle-filled tunnels. Whereas this would normally physically restrict cell motility, when the particulate network is created using ultralow cross-linked microgels, the colloidal suspension displays viscous behavior on the same timescale as cell spreading and migration and thus enables efficient cell infiltration of the construct through the colloidal-filled tunnels.fibrin | microgels | colloidal assemblies | porosity | cell migration D ecoupling stiffness, pore size, and cell infiltration is a critical hurdle in biomaterials design and has been previously addressed in synthetic hydrogels by enabling cell-mediated degradation via protease-specific peptide cross-linkers (1-4). However, even in these highly engineered systems, compared with native extracellular matrices (ECMs), the mesh size remains a critical limiting factor in host integration; this is because cells are incapable of nonproteolytic, i.e., degradation-independent, migration through such small mesh sizes (5), as illustrated in Fig. 1A.Protein-based biomaterials derived from native ECM represent an attractive alternative to synthetic hydrogels, offering significant benefits through their enhanced endogenous bioactivity. The native ECM and its derivatives act as growth factor/cytokine depots, thus providing a multivalent endogenous binding site for growth factor delivery (6). A classic example of this type of biomaterial is fibrin, the endogenous provisional matrix formed at sites of vascular injury as a result of blood coagulation (7,8). Clinically, to reach desirable mechanical properties for sealing tissues/wounds, fibrin is used at supraphysiological concentrations typically containing ∼10× more fibrinogen than physiological concentrations (9-12). When used at these artificially high concentrations, the characteristic mesh size of the network is unfortunately similar to that of synthetic PEG polymers, which is on the order of tens of nanometers, making i...

Although block copolymer motifs have received considerable attention as supramolecular templates for inorganic nanoparticles, experimental observations of a nanostructured diblock copolymer containing inorganic nanoparticles-supported by theoretical trends predicted from a hybrid self-consistent field/density functional theory-confirm that nanoparticle size and selectivity can likewise stabilize the copolymer nanostructure by increasing its order-disorder transition temperature.

A novel microfluidic thread/paper-based analytical device (μTPAD) to detect glucose through a colorimetric assay is described. The μTPAD was fabricated from nylon thread trifurcated into three channels terminating at analysis sites comprised of circular zones of chromatography paper, which have previously been spotted with glucose of different concentrations. A solution of glucose oxidase (GOx), horseradish peroxidase (HRP), and potassium iodide (KI) is transported via capillary action to the analysis sites where a yellow-brown color is observed indicating oxidation of iodide to iodine. The device was then dried, scanned, and analyzed yielding a correlation between yellow intensity and glucose concentrations. Both a flat platform constructed mainly of tape, and a cone platform constructed from tape and polyvinyl chloride, are described. Studies to quantitate glucose in artificial urine showed good correlation using the μTPAD.

An electrochemical sensor for the detection of glucose using thread-based electrodes and fabric is described. This device is relatively simple to fabricate and can be used for multiple readings after washing with ethanol. The fabrication of the chip consisted of two steps. First, three thread-based electrodes (reference, working, and counter) were fabricated by painting pieces of nylon thread with either layered silver ink and carbon ink or silver/silver chloride ink. The threads were then woven into a fabric chip with a beeswax barrier molded around the edges in order to prevent leaks from the tested solutions. A thread-based working electrode consisting of one layer of silver underneath two layers of carbon was selected to fabricate the final sensor system. Using the chip, a PBS solution containing glucose oxidase (GOx) (10 mg/mL), potassium ferricyanide (K [Fe(CN) ]) (10 mg/mL) as mediator, and different concentrations of glucose (0-25 mM), was measured by cyclic voltammetry (CV). It was found that the current output from the oxidation of glucose was proportional to the glucose concentrations. This thread-based electrode system is a viable sensor platform for detecting glucose in the physiological range.