Modeling and characterization of glucose-sensitive hydrogel: Effect of Young's modulus

Hydrolysis effects on the water uptake of starch-g-glycidyl methacrylate (GMASt)/dimethylacrylamide (DMAAm)-based hydrogels for potential agricultural purposes

This work assessed the effect of different hydrolysis periods on the properties of hydrogels based on 75 % w w-1 of N,N'-dimethyl acrylamide (DMAAm) and 25 % w w-1 of starch-g-(glycidyl methacrylate) (GMASt). FTIR results confirmed the conversion of ester groups into carboxylic acids and carboxylates, besides forming a keto-enol tautomer due to the peeling reaction of starch. For DMAAm, the hydrolysis mostly converted amide into carboxylate groups. The morphology, thermal stability, and the mechanical properties of the predominantly amorphous matrices (as confirmed by XRD results) did not drastically change even after 10 days of hydrolysis in alkali media. However, the thermogravimetric analysis results suggested that DMAAm partially protected GMASt from the hydrolysis. The swelling degree of the matrix increased from (10.1 ± 2.1) g g-1 to (61.9 ± 2.6) g g-1 after 1 day of hydrolysis, but no statistical differences (at 95 % of significance) were observed for the matrices hydrolyzed for longer periods, confirming that the maximum hydrolysis occurred within 24 h. The results confirmed that the hydrolysis increased the water uptake of the GMASt/DMAAm-based matrices, making appealing for uses as a water retentor for agricultural purposes.

Glucose Oxidase-Based Glucose-Sensitive Drug Delivery for Diabetes Treatment

The glucose-sensitive drug delivery systems based on glucose oxidase (GOD), which exhibit highly promising applications in diabetes therapy, have attracted much more interest in recent years. The self-regulated drug delivery systems regulate drug release by glucose concentration automatically and continuously to control the blood glucose level (BGL) in normoglycemic state. This review covers the recent advances at the developments of GOD-based glucose-sensitive drug delivery systems and their in vivo applications for diabetes treatment. The applications of GOD-immobilized platforms, such as self-assembly layer-by-layer (LbL) films and polymer vesicles, cross-linking hydrogels and microgels, hybrid mesoporous silica nanoparticles, and microdevices fabricated with insulin reservoirs have been surveyed. The glucose-sensitive drug delivery systems based on GOD are expected to be a typical candidate for smart platforms for potential applications in diabetes therapy.

Preparation of conductive composite hydrogels from carboxymethyl cellulose and polyaniline with a nontoxic crosslinking agent

A cellulose based conductive composite hydrogel was prepared with a non-toxic crosslinking agent for application in biomedical materials.

CMOS image sensors as an efficient platform for glucose monitoring

Complementary metal oxide semiconductor (CMOS) image sensors have been used previously in the analysis of biological samples. In the present study, a CMOS image sensor was used to monitor the concentration of oxidized mouse plasma glucose (86-322 mg dL(-1)) based on photon count variation. Measurement of the concentration of oxidized glucose was dependent on changes in color intensity; color intensity increased with increasing glucose concentration. The high color density of glucose highly prevented photons from passing through the polydimethylsiloxane (PDMS) chip, which suggests that the photon count was altered by color intensity. Photons were detected by a photodiode in the CMOS image sensor and converted to digital numbers by an analog to digital converter (ADC). Additionally, UV-spectral analysis and time-dependent photon analysis proved the efficiency of the detection system. This simple, effective, and consistent method for glucose measurement shows that CMOS image sensors are efficient devices for monitoring glucose in point-of-care applications.

Real-time clinical monitoring of biomolecules

Continuous monitoring of clinical biomarkers offers the exciting possibility of new therapies that use biomarker levels to guide treatment in real time. This review explores recent progress toward this goal. We initially consider measurements in body fluids by a range of analytical methods. We then discuss direct tissue measurements performed by implanted sensors; sampling techniques, including microdialysis and ultrafiltration; and noninvasive methods. A future directions section considers analytical methods at the cusp of clinical use.