Theranostic Contact Lens for Ocular Cystinosis Utilizing Gold Nanoparticles.

Ocular cystinosis is a disease in which accumulated cystine crystals cause damage to the eyes, necessitating timely treatment and ongoing monitoring of cystine levels. The current treatment involves frequent administration of cysteamine eye drops, which suffer from low bioavailability and can lead to drug toxicity, making it essential to prescribe an appropriate dosage based on the patient's condition. Additionally, cystine crystal levels are typically assessed subjectively via slit-lamp examination, requiring frequent clinical visits and causing discomfort for the patient.

Signal Amplification by Spatial Concentration for Immunoassay on Cellulose Media.

Immunoassay is one of the most common bioanalytical techniques from lab-based to point-of-care settings. Over time, various approaches have been developed to amplify signals for greater sensitivity. However, the need for effective, versatile, and simple signal amplification methods persists yet.

Advancements in Nanogels for Enhanced Ocular Drug Delivery: Cutting-Edge Strategies to Overcome Eye Barriers.

Nanomedicine in gel or particle formation holds considerable potential for enhancing passive and active targeting within ocular drug delivery systems. The complex barriers of the eye, exemplified by the intricate network of closely connected tissue structures, pose significant challenges for drug administration. Leveraging the capability of engineered nanomedicine offers a promising approach to enhance drug penetration, particularly through active targeting agents such as protein peptides and aptamers, which facilitate targeted release and heightened bioavailability.

Paper-Based Substrate for a Surface-Enhanced Raman Spectroscopy Biosensing Platform-A Silver/Chitosan Nanocomposite Approach.

Paper is a popular platform material in all areas of sensor research due to its porosity, large surface area, and biodegradability, to name but a few. Many paper-based nanocomposites have been reported in the last decade as novel substrates for surface-enhanced Raman spectroscopy (SERS). However, there are still limiting factors, like the low density of hot spots or loss of wettability.

Paper-Based Diagnostic System Facilitating Assessments by Duplex Coloration.

Laboratory support for low-resource regions is a rising global issue. As microbiological contamination is closely associated with other issues like food safety, water supply sustainability, and public health, bacterial assessments in this setting need to be improved. Herein, we demonstrate a paper-based diagnostic device for point-of-need testing, in which fecal-indicating and highly pathogenic are detected by duplex coloration.

Probabilistic ecological risk assessment of heavy metals using the sensitivity of resident organisms in four Korean rivers.

The environment has been continuously exposed to heavy metals by various routes, from both natural and artificial sources. In particular, heavy metals in water can affect aquatic organisms adversely, even at very low concentrations, and can lead to the disturbance of the ecosystem balance and biodiversity. Ecological risk assessments are conducted to protect the environment from such situations, primarily by deriving the predicted no-effect concentration (PNEC) from the species sensitivity distribution (SSD).

One-step sensing of foodborne pathogenic bacteria using a 3D paper-based device.

Managing food contamination from bacteria has been an ongoing issue in the public health and industrial fields. Enzymatic substrates possessing optical properties, e.g.

Size and Surface Charge of Engineered Poly(amidoamine) Dendrimers Modulate Tumor Accumulation and Penetration: A Model Study Using Multicellular Tumor Spheroids.

An enormous effort has been put into designing nanoparticles (NPs) with controlled biodistributions, prolonged plasma circulation times, and/or enhanced tissue targeting. However, little is known about how to design NPs with precise distributions in the target tissues. In particular, understanding NP tumor penetration and accumulation characteristics is crucial to maximizing the therapeutic potential of drug molecules carried by the NPs.

Hazard Classification of Household Chemical Products in Korea according to the Globally Harmonized System of Classification and labeling of Chemicals.

Objectives: This study was conducted to review the validity of the need for the application of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) to household chemical products in Korea. The study also aimed to assess the severity of health and environmental hazards of household chemical products using the GHS.

Methods: 135 products were classified as 'cleaning agents and polishing agents' and 98 products were classified as 'bleaches, disinfectants, and germicides.

Electrophoretic implementation of the solution-depletion method for measuring protein adsorption, adsorption kinetics, and adsorption competition among multiple proteins in solution.

The venerable solution-depletion method is perhaps the most unambiguous method of measuring solute adsorption from solution to solid particles, requiring neither complex instrumentation nor associated interpretive theory. We describe herein an SDS-gel electrophoresis implementation of the solution--depletion method for measuring protein adsorption and protein-adsorption kinetics. Silanized-glass particles with different surface chemistry/energy and hydrophobic sepharose-based chromatographic media are used as example adsorbents.

Volumetric interpretation of protein adsorption: interfacial packing of protein adsorbed to hydrophobic surfaces from surface-saturating solution concentrations.

The maximum capacity of a hydrophobic adsorbent is interpreted in terms of square or hexagonal (cubic and face-centered-cubic, FCC) interfacial packing models of adsorbed blood proteins in a way that accommodates experimental measurements by the solution-depletion method and quartz-crystal-microbalance (QCM) for the human proteins serum albumin (HSA, 66 kDa), immunoglobulin G (IgG, 160 kDa), fibrinogen (Fib, 341 kDa), and immunoglobulin M (IgM, 1000 kDa). A simple analysis shows that adsorbent capacity is capped by a fixed mass/volume (e.g.

Fluidic timers for time-dependent, point-of-care assays on paper.

This article describes an integrated approach to tracking the end point of a time-based assay that is conducted on an analytical device made out of paper. The timing mechanism is built directly into a paper-based analytical device and does not require starting, stopping, reset buttons, batteries, or maintenance; the timer simply starts once the sample is added to the device. These "fluidic timers" are composed of paraffin wax and a signaling feature (e.

Metering the capillary-driven flow of fluids in paper-based microfluidic devices.

This article describes an exceedingly simple and low-cost method for metering the capillary-driven flow rate of fluids within three-dimensional (3D) microfluidic, paper-based analytical devices (microPADs). Initial prototypes of 3D microPADs control the spatial distribution of fluids within a device, but they provide little control over how quickly (or slowly) fluids move within the device. The methods described in this article provide control over when and how quickly a fluid is distributed into detection zones.

Volumetric interpretation of protein adsorption: capacity scaling with adsorbate molecular weight and adsorbent surface energy.

Silanized-glass-particle adsorbent capacities are extracted from adsorption isotherms of human serum albumin (HSA, 66 kDa), immunoglobulin G (IgG, 160 kDa), fibrinogen (Fib, 341 kDa), and immunoglobulin M (IgM, 1000 kDa) for adsorbent surface energies sampling the observable range of water wettability. Adsorbent capacity expressed as either mass-or-moles per-unit-adsorbent-area increases with protein molecular weight (MW) in a manner that is quantitatively inconsistent with the idea that proteins adsorb as a monolayer at the solution-material interface in any physically-realizable configuration or state of denaturation. Capacity decreases monotonically with increasing adsorbent hydrophilicity to the limit-of-detection (LOD) near tau(o) = 30 dyne/cm (theta approximately 65 degrees) for all protein/surface combinations studied (where tau(o) identical with gamma(lv)(o) costheta is the water adhesion tension, gamma(lv)(o) is the interfacial tension of pure-buffer solution, and theta is the buffer advancing contact angle).

Volumetric interpretation of protein adsorption: kinetic consequences of a slowly-concentrating interphase.

Time-dependent energetics of blood-protein adsorption are interpreted in terms of a slowly-concentrating three-dimensional interphase volume initially formed by rapid diffusion of protein molecules into an interfacial region spontaneously formed by bringing a protein solution into contact with a physical surface. This modification of standard adsorption theory is motivated by the experimental observation that interfacial tensions of protein-containing solutions decrease slowly over the first hour to a steady-state value while, over this same period, the total adsorbed protein mass is constant (for lysozyme, 15 kDa; alpha-amylase, 51 KDa; albumin, 66 kDa; prothrombin, 72 kDa; IgG, 160 kDa; fibrinogen, 341 kDa studied in this work). These seemingly divergent observations are rationalized by the fact that interfacial energetics (tensions) are explicit functions of solute chemical potential (concentration), not adsorbed mass.

Volumetric interpretation of protein adsorption: ion-exchange adsorbent capacity, protein pI, and interaction energetics.

Adsorption of lysozyme (Lys), human serum albumin (HSA), and immunoglobulin G (IgG) to anion- and cation-exchange resins is dominated by electrostatic interactions between protein and adsorbent. The solution-depletion method of measuring adsorption shows, however, that these proteins do not irreversibly adsorb to ion-exchange surfaces, even when the charge disparity between adsorbent and protein inferred from protein pI is large. Net-positively-charged Lys (pI=11) and net-negatively-charged HSA (pI=5.

Surface energy effects on osteoblast spatial growth and mineralization.

While short-term surface energy effects on cell adhesion are relatively well known, little is revealed as regards its later stage effects on cell behavior. We examined surface energy effects on osteoblastic cell growth and mineralization by using human fetal osteoblastic (hFOB) cells cultured on plasma-treated quartz (contact angle, theta=0 degrees) and octadecyltrichlorosilane (OTS)-treated quartz (theta=113 degrees). hFOB cells formed a homogeneous cell layer on plasma-treated quartz, while those cultured on OTS-treated quartz produced randomly distributed clump-like structures that were filled with cells (confirmed by confocal microscopy).

Volumetric interpretation of protein adsorption: competition from mixtures and the Vroman effect.

A Vroman-like exchange of different proteins adsorbing from a concentrated mixture to the same hydrophobic adsorbent surface is shown to arise naturally from the selective pressure imposed by a fixed interfacial-concentration capacity (w/v, mg/mL) for which protein molecules compete. A size (molecular weight, MW) discrimination results because fewer large proteins are required to accumulate an interfacial w/v concentration equal to smaller proteins. Hence, the surface region becomes dominated by smaller proteins on a number-or-mole basis through a purely physical process that is essentially unrelated to protein biochemistry.

Volumetric interpretation of protein adsorption: mass and energy balance for albumin adsorption to particulate adsorbents with incrementally increasing hydrophilicity.

The solution-depletion method of measuring human serum albumin (HSA) adsorption to surface-modified glass-particle adsorbents with incrementally increasing hydrophilicity is implemented using SDS gel electrophoresis as a separation and quantification tool. It is shown that adsorbent capacity for albumin measured in interfacial-concentration units (mg/mL) decreases monotonically with increasing surface energy (water wettability) to detection limits near an adsorbent-particle water adhesion tension tau(0)=30 dyne/cm (nominal water contact angle theta=65( composite function)) and that albumin does not adsorb to (concentrate within the surface region of) more hydrophilic adsorbents. These adsorbed-mass measurements corroborate predictions based on interfacial energetics and are consistent with AFM measurement of protein-surface adhesion.

Volumetric interpretation of protein adsorption: Partition coefficients, interphase volumes, and free energies of adsorption to hydrophobic surfaces.

The solution-depletion method of measuring protein adsorption is implemented using SDS gel electrophoresis as a separation and quantification tool. Experimental method is demonstrated using lysozyme (15kDa), alpha-amylase (51kDa), human serum albumin (66kDa), prothrombin (72kDa), immunoglobulin G (160kDa), and fibrinogen (341kDa) adsorption from aqueous-buffer solution to hydrophobic octyl-sepharose and silanized-glass particles. Interpretive mass-balance equations are derived from a model premised on the idea that protein reversibly partitions from bulk solution into a three-dimensional (3D) interphase volume separating the physical-adsorbent surface from bulk solution.