Biology subjects

Matoori, S.

Publications and source records attributed to Matoori, S..

6 recordsLinked to original sources

bioRxiv2026

Click alginate cryogel for real-time gastric pH monitoring

Gastric acidity shapes mucosal injury in reflux disease, peptic ulcer, and gastritis, yet is almost never measured. Acid-suppressive therapy, taken by approximately 40% of elderly adults, is therefore titrated on symptoms alone. A gastric sensor must hold onto its reporter in a highly acidic protease-rich environment, conditions that destabilize ionically crosslinked hydrogels and leach physically entrapped dyes. Click alginates, established in biomechanics and drug delivery but not as sensors, meet this requirement with a single chemistry: bioorthogonal tetrazine-norbornene crosslinks are inert to acid and proteases, and excess norbornene from crosslinking become the anchoring site for the pH-sensitive reporter, so network and reporter are installed by the same mechanism. Cryogelation adds macroporosity for rapid gastric fluid influx. A screen identifies IRDye 680RD as the only near-infrared dye responsive across the targeted pH 2-5. Dye release stays below 1.5% in simulated gastric and intestinal fluids, and the pH response remains active after nine months of storage. In rats, the orally administered NIR fluorescent cryogel resolves pH 2.0 from pH 5.0 transabdominally, and discriminates esomeprazole- from saline-treated animals, without plasma fluorescence. Photoacoustic imaging points toward detection at translationally relevant depths, establishing covalently functionalized cryogels as a general sensing platform for hostile physiological environments.

bioengineering↗

bioRxiv2026

Off-the-shelf NIR-I fluorophores as ready-to-use NIR-II probes: screening and in vivo validation

Fluorescence imaging in the second near-infrared window (NIR-II, 950-1700 nm) offers reduced scattering, lower autofluorescence, and deeper tissue penetration than NIR-I imaging, but its adoption is limited by the need for custom-synthesized fluorophores. Here, we identify commercially available dyes that exhibit usable NIR-II emission. Eleven visible, far-red, and NIR-I fluorophores were screened under twelve acquisition configurations combining 670, 760, and 808 nm excitation with band-pass (950 nm, 1400 nm) or long-pass (1000 nm, 1250 nm) emission filters. Output varied markedly with fluorophore identity and excitation/emission configuration. Among hydrophobic dyes, DiR exhibited strong emission across almost all excitation and emission filters. Among hydrophilic dyes, strong NIR-II fluorescence was observed for IRDye 680RD (excitation at 670 nm), sulfo-cyanine 7 (excitation at 670 nm and 760 nm), and indocyanine green (excitation at 808 nm). DiR showed a linear concentration-response under 760 nm excitation with BP1400 detection. Upon encapsulation in PEGylated liposomes, strong NIR-II fluorescence was retained. In an in vivo study in mice, NIR-II resolved vasculature that NIR-I could not consistently delineate, and enabled pharmacokinetic analysis. Both windows returned similar ex vivo organ distributions. NIR-II imaging is therefore accessible using commercial off-the-shelf fluorophores, provided the dye is matched to the intended excitation/emission configuration.

bioengineering↗

bioRxiv2026

Colorimetric Hydrogel Dressing with Smartphone Detector for Point-of-Care Wound pH Monitoring

Chronic wounds such as diabetic foot ulcers are typically more alkaline than healing wounds, making wound pH a valuable diagnostic and prognostic marker. However, point-of-care pH monitoring remains limited by the availability of point-of-care wound pH sensing systems that offer quantitative pH determination, low toxicity, and small portable detectors. Here, we report a colorimetric pH-sensing wound dressing that enables in situ pH detection using a conventional smartphone camera. The anionic pH-sensitive dye HPTS was loaded onto cationic microparticles and embedded within a calcium-crosslinked alginate hydrogel. Across the clinically relevant range of pH 6.0-9.0, increasing pH produced a progressively more intense yellow coloration, quantified through the blue channel of smartphone-acquired RGB images. The dressing displayed a strong, rapid, and reversible signal in vitro with low dye release. In a full-thickness excisional wound model in mice, wound pH changes were detected in vivo. The combination of a pH-sensitive colorimetric hydrogel with a conventional smartphone detector offers accessible wound pH monitoring at the point-of-care.

bioengineering↗

bioRxiv2024

Colorimetric detection methods of pH-sensing wound dressing for point-of-care wound diagnostics

Chronic lower extremity wounds like diabetic foot ulcers (DFUs) are a major complication of diabetes and the leading cause of lower limb amputations worldwide. Currently, DFUs are diagnosed through macroscopic evaluation, and molecular diagnostics are lacking for the disease staging, treatment selection, and evaluation of treatment success. There is a need for new diagnostic technologies combined with detection methods for point-of-care use. Preclinical and clinical data support the importance of wound pH as a biomarker in chronic wound healing, with DFUs typically exhibiting more alkaline pH values when compared to normal healing wounds. In a previous study, we developed a pH-sensing fluorescent bandage based on pyranine-loaded microparticles that were physically immobilized in an alginate hydrogel. Here, we present a second-generation pH-sensing bandage for colorimetric wound diagnostics. Pyranine was adsorbed at high concentrations onto microparticles to enable colorimetric signal detection. This approach leverages pyranines ability to change color in response to pH variations through proton exchange properties with the wound fluid. The colorimetric properties of our bandage enable signal detection by two methods suited for point-of-care use: a smartphone camera and a cost-effective homebuilt RGB detector. Analyzing the color intensity of the bandage with Red, Green and Blue absorbance values, it is possible to correlate the RGB absorbance to a pH value in the clinically-relevant range to 6.0 to 9.0 in vitro and ex vivo, as the B values decreased with the increase in pH levels, as associated with DFUs. These findings indicate the potential of colorimetric detection using smartphone cameras or home-built absorbance detectors for rapid wound diagnostics at the point-of-care. Graphical AbstractA pH-sensing bandage enables colorimetric detection of chronic wounds. The bandage absorbs wound exudate, triggering proton exchange with dye-loaded microparticles in an alginate matrix. Chronic wounds with high pH values induce strong fluorescence and yellow coloration. The signal is quantified through RGB colorimetry analysis using a smartphone camera or a homebuilt RGB detector, enabling point-of-care diagnostics for chronic wounds. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=141 SRC="FIGDIR/small/617850v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@19aba53org.highwire.dtl.DTLVardef@13eb582org.highwire.dtl.DTLVardef@1fe8831org.highwire.dtl.DTLVardef@19f5231_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Fluorescent pH-sensing bandage for point-of-care wound diagnostics

Diabetic foot ulcers (DFUs) are a serious and prevalent complication of diabetes. Current diagnostic options are limited to macroscopic wound analysis such as wound size, depth, and infection. Molecular diagnostics promise to improve DFU diagnosis, staging, and assessment of treatment response. Here, we developed a rapid and easy-to-use fluorescent pH-sensing bandage for wound diagnostics. In a fluorescent dye screen, we identified pyranine as the lead compound due to its suitable pH-sensing properties in the clinically relevant pH range of 6 to 9. To minimize the release of this dye into the wound bed, we screened a library of ionic microparticles and found a strong adhesion of the anionic dye to a cationic polymeric microparticle. These dye-loaded microparticles showed a strong fluorescence response in the clinically relevant pH range of 6 to 9 and a dye release below 1% after one day in biological media. The dye-loaded microparticles were subsequently encapsulated in a calcium alginate hydrogel to minimize the interaction of the microparticles with the wound tissue. This pH-sensing diagnostic wound dressing was tested on full thickness dorsal wounds of mice, and a linear fluorescence response (R2 = 0.9909) to clinically relevant pH values was observed. These findings encourage further development of this pH-sensing system for molecular diagnostics in DFUs.

pharmacology and toxicology↗

bioRxiv2019

An investigation of PS-b-PEO polymersomes for the oral treatment and diagnosis of hyperammonemia

Ammonia-scavenging transmembrane pH-gradient poly(styrene)-b-poly(ethylene oxide) polymersomes were investigated for the oral treatment and diagnosis of hyperammonemia, a condition associated with serious neurologic complications in patients with liver disease as well as in infants with urea cycle disorders. While these polymersomes were highly stable in simulated intestinal fluids at extreme bile salt and osmolality conditions, they unexpectedly did not reduce plasmatic ammonia levels in cirrhotic rats after oral dosing. Incubation in dietary fiber hydrogels mimicking the colonic environment suggested that the vesicles were probably destabilized during the dehydration of the intestinal chyme. Our findings question the relevance of commonly used simulated intestinal fluids for studying vesicular stability. With the encapsulation of a pH-sensitive dye in the polymersome core, the local pH increase upon ammonia influx could be exploited to assess the ammonia concentration in the plasma of healthy and cirrhotic rats as well as in other fluids. Due to its high sensitivity and selectivity, this novel polymersome-based assay could prove useful in the monitoring of hyperammonemic patients and in other applications such as drug screening tests.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=94 SRC=\"FIGDIR/small/631630v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (28K):\norg.highwire.dtl.DTLVardef@dd9b02org.highwire.dtl.DTLVardef@ebb129org.highwire.dtl.DTLVardef@1bc15e3org.highwire.dtl.DTLVardef@1411a28_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗